a mineralogical study of the hemo-ilmenite ore …
TRANSCRIPT
GM 35775A MINERALOGICAL STUDY OF THE HEMO-ILMENITE ORE FROM LAC TIO
A MINERALOGICAL STUDY OF THE HEMO—ILMENITE ORE
FROM LAC TIO, QUEBEC
by
Michel Bergeron
Ministère de l'Énergie et des Ressources Gouvernement du Québec Documentation Technique QUE: 1980 MAPS 0 5
No. QM: 36/1S
Feb. 73
I
A MINERALOGICAL STUDY OF HEMO-ILMENITE ORE FROM LAC TIO, OUEBEC
ABSTRACT
The Lac Tio orebody consista of a large deposit of massive
hemo-ilmenite within andesine anorthosite rocks. The deposit has been
mined continuously since 1951 by the Quebec Iron and Titanium Corporation.
It is located some 22 miles north of Havre St-Pierre, a small sea port on
the north coast of the St.Lawrence River.
The purpose of this work has been to study in detail the
mineralogy and chemistry of the hemo-ilmenite ore in order to detect
possible chemical and mineralogical variations within the orebody. The
work involved the systematic study of 135 specimens cif ore by X-ray
diffraction, the complete chemical analyses of 48 high purity hemo-
ilmenite concentrates, and the microscopic and electron probe exam-
ination of some 40 polished sections.
Our study shows that the Fe-Ti ore is almost entirely made up
of hemo-ilmenite, of average composition 70% ilmenite and 30% hematite,
unmixed to a regular intergrowth of hematite and ilmenite. Microprobe
analyses and crystal chemical considerations indicate that the average
composition of the unmixed phases is : (144.11814n. 00.4Fe .873C1.004)Ti°3
14A1 012Cr.004)203. Other minerals identified in the ore and (Fe,971y.0
consist of accessory amounts of plagioclase (An46, commonly antiperthitic),
pleonaste spinel, and pyrite, as well as minor or trace quantities of
magnetite, chlorite, hypersthene, zalcite, zircon, corundum, apatite,
chalcopyrite, millerite, pyrrhotite, Co-Ni sulphides (linaeite series),
II
rutile and anatase. rrimary magnetite is almost absent in the ore;
the most common magnetite is secondary in origin and together with
anatase and rutile has formed at the expense of hemo-ilmenite during the
subsolidus stage. The study of the variation of the hemp-ilme:.tite chemistry
throughout the orebody indicates that the mineral deviates little from
the average composition. All attempts to find regular or stratigraphic
variations of the minor elements (Mg, Mn, Cr, Al, V) of the hemo-ilmenite
were unsuccessful.
The geology End origin of the deposit is reviewed in the light
of our data. It is suggested that the ore crystallized from an oxide melt
that separated by liquid immiscibility early in the evolution of the
regional anorthosit:e mass{,f. From textural evidence it is concluded
that b emo-ilmenite accumulated by crystal settling. The lack of fraction-
ation trends in the ore is attributed to repeated injections of oxide
magmas and to a slow rate of crystallization which favored adcumslus
growth of the hemo-ilmenite crystals.
ETUDE MINERALOGIQUE D;: MINERAI D'HEMO-ILMENITE DU LAC TIO QUEBEC
Résumé
Le gisement du Lac Tio est constitué d'un amas massif d'hémo-
ilménite â l'intérieur d'un complexe anorthositique de type anorthosite
A and.ésine. Ce dépôt, exploité depuis 1951 par la société Fer et Titane
du Québec, est situés environ 22 milles au nord de Havre St-Pierre,
petit port de mer sur la rive nord du fleuve St-Laurent.
L"objectif de ce travail était de déceler d'éventuelles varia-
tions minéralogiques et chimiques dans le gisement par une étude détail-
lée de la composition du minerai. Le travail est basé sur l'é,ude systé-
matique de 135 échantillons de minerai par diffraction des rayons-X,
sur l'analyse chimique de 48 concentrés d'hémo-ilménite de très grande
pureté et sur l'examen au microscope et à la microsonde d'environ 40
sections polies.
Nous avons montré que le minerai de fer et de titane est com-
posé presqu'exclusivement d'hémo-ilménite qui se présente sous forme
d'une intercroissance lamellaire régulière formée d'environ 70% d'ilmé-
nite et de 30% d'hématite. Les analyses à la microsonde et les données
ct'istallochimiques in-liguent que la composition moyenne de chacune des
phases exsudeés est la suivante (Mg.118M.004Fe.873Ca.W4)TiO3 et
(Fe.0.,1V.014M .012G1 .004)203. Les minéraux. . - c.essoires identifiés dans
le minerai sont le plagioclase (An46, communément an~::lperthitique), le
spinelle de type pléonaste et la pyrite. De petites quantités, voire des
traces, de magnétite, chalcopyrite, chlorite ;, rutile, hyperathène, pyrrho-
IV
tine, anatase, zircon, corindon, apatite, willerite,calci:e et des sul-
fures de cobalt et de nickel (série linaeite) sont aussi 1résentes. La
magnétite primaire est presque inexistante dans le minerai, la magnétite
la plus commune dans le minerai est d'origine secondaire: islle s'est
formée, tout comme le rutile et l'anatase, à varti.r d'hémo-iiménite lors
du stade subsolidus. L'étude des vari itior i. de la compositaio. chimique
de l'hémo-ilménite dans le gisement montre qu'elle s'écarte p:u de la
composition moyenne. Tous nos efforts visant à prouver l'existence de
variations régulières ou stratigraphiques dans les éléments mi•aeurs (Mg,
Mn, Cr, Al, V) d:~ i'hémo-ilménite ont été infructueux.
Une étude de la genèse et de l'histoire du gisement à la lumière
de nos résultats, nous amène à considérer que le minerai a cristallisé à
partir d'un fondu d'oxydes ("ore magma") qui ze serait formé par immisci-
bilit:é au tout début de l'évolution du massif anorthositique régional.
Les données texturales du minerai n7us portent à conclure que le liquide
magmatique injecté dans l'anorthosite solidifiée a cristallisé par cris-
tallisat-`.on fractionnée sous l'influence de la gravité. L'absence de
variations stratigraphiques dans le minerai est attribuée à des injections
répétées de magma et à un taux de cristallisation plutôt lent favorisant
ainsi une croissance "adcumulus" des cristaux d'hémo-ilménite.
m'Ans a matneaao:visxawmimmaimasianfiauaAial
,dHUM~~es~►~~~e~~ ri~wa~s■oo~
V
TABLE OF CONTENTS
2241
ABSTRACT
INTRODUCTION 1
Chapter I
GEOLOGY OF THE LAC ALLARD AREA 3
1.1 Introduction 3 1.2 Location 3 1.3 Previous Work and History of the Area 6 1.4 Physical Geography 8 1.5 General Geology . .. 10
1.5.1 "Grenville Series" of Retty (1944) ....... 12
1.5.1.1 Quartzite 12 1.5.1.2 Hornblende Gneiss and Biotite Gneiss 12 1.5.1.3 Garnetiferous Gneiss 12 1.5.1.4 Less Common Rocks of the "Grenville
Series" in the Area 12
1.5.2 "Morin Series" of Retty (1944)
1.5.2.1 Anorthosite ., 1.5.2.2 Anorthosite with Coarse Pyroxene
Crystals 1.5 ,.2.3 Ilmenite Rich Anorthosite 1.5.2.4 Anorthosite Dykes
1.5.3 Granitic Rocks 15 1.5.4 Diorite, Gabbro and Metagabbro 4,1 15
1.5.5 Pleistocene and Recent 15
1.6 Structural Geology 17 1.7 Economic Geology 18
1.7.1 Introduction 18 1.7.2 The Lac Tio Deposit 19
1.7.2.1 General Mineralogy and Chemistry
of the Lac Tio Deposit ........... 22
1.7.2.2 Faulting of the Lac Tic Oreboc1r .. 26 1.7.2.3 Magnetic Property of the Lac Tio
Hemo--Ilmenite ....."..........w.... 32
13
13
14 114 15
__
Chapter II
Yaffe
MINERALOGY OF THE LAC TIO HEMO-I_LMENITE DEPOSIT 35
2.1 Introduction 35 2.2 Description of Minerals 35
2.2.1 Hemo-Ilmenite 35
2.2.1.1 General Megascopic and Microscopic Characteristics 35.
2.2.1.2 Chemical Composition of Hlmo-I2menite 39 2.2.1.3 Minor Element Distribution in Unmixed
Ilmenite and Hematite ... 47 2.2.1.4 Lattice Parameters and Composition of
Unmixed Hematite and Ilmenite 44 2.2.1.5 Distribution and Variation of ilmenite
and Hematite in the Ore7lody 49
2.2.2 Plagiaiciase . .... 51
2.2.3 Sulphides . 54
2.2.3.1 General Distribution . .. 54 2.2.3.2 Chemistry of the Sulphides ......... 56
2.2.1+ Spinel 5T 2.2.5 Magnetite 61 2.2.6 Rutile and Anatase 65 2.2.7 Chlorite and Biotite 68 2.2.8 Apatite, Corundum and Zircon 71 2.2.9 Hypersthene and Calcite 75
2.3 Mineralogical Summary 75
Chapter III
GEOCHEMISTRY OF HEMO-ILMENITES FROM THE LAC TIO DEPOSIT 8o
3.1 Introduction 80 3.2 Selection and Preparation of Material for Study 80 3.3 Analytical Methods and Preparation of an Hemo-
Ilmenite Standard 83 3.4 Chemistry of Hemo-Ilmenites in the Deposit 85 3.5 Chemical Variations of Hemo-Ilmenite in the Orebody 87 3.6 Inter-element Correlations in Hemo-Ilmenites 94 3.7 Synopsis of Hemo-Ilmeni.se Chemistry 103
romaimummiummull
VII
CERTAIN ASPECTS OF THE PETROLOGY AND ORIGIN OF THE LAC TIO DEPOSIT 106
4.1 Introduction 106 4.2 Metallogenic Traits of the Lac Tio Deposit ' 106 4.3 Crystallization and Evolution of the Hemo-ilmenite
Magma 109 4.4 Subsolidus Evolution of the Hemo•-Ilmenite 114 4.5 Concluding Statement 118
BIBLIOGRAPHY
119
ACKNOWLEDGEMENTS . 124
APPENDICE:
I Preparation and Chemical Analysis of 48 Lac Tio Hemo- Ilmenite Concentrates 125
II Preparation and Chemical Analysis of a Hemo-Ilmenite Standard 132
III Distribution of FeO, Fe203, A1203 and Cr203 in the Lac Tio Orebody 136
Page
Chapter IV
1MOSN®~i "i "i I~HCMMOAIOMMIEL
VIII
TABLE DES MATIERES
RESUME
INTRODUCTION
Chapitre I
GEOLOGIE DE LA REGION DU LAC ALLARD
Page
III
1
3
1.1 1.2 1.3 1.14 1.5
Introduction, ...,, Situation .. Travaux antérierars et histoire de la région Géographie physique Géologie généra:.e DO
3 3 6 8 10
1.5.1 "Série de Grenville" d'apras Retty(1944). 12
1.5.1.1 Quartzite 12 1.5.1.2 Gneiss â hornblende et gneiss â
biotite 12 1.5.1..; Gneiss grenatifére 12 1.5.1.4 Roches de la "Série de Grenville"
peu communes dans la region 12
1.5.2 "Série: de Morin" d'après Retty (1944) 13
1.5.2.1 Anorthosite 13 1.5.2:.2 Anorthosite renfermant de gros
cristaux de pyroxène 14 1.5.2.3 Anorthosite riche en ilménite 14 1.5.2.1+ Dykes d'anorthosite 15
1.5.3 Roches granitiques 15 1.5.11 Diorite, gabbro et métagabbro 15 1.5.5 Pleistocéne et Récent 15
1.6 Géologie utructurale 17 1.7 Géologie 4concmique 18
1.7.1 Introduction 18 1.7.2 Le gisement du Lac Tio 19
1.7.2.1 Minéralogie et chimie générale du gisement %
x..7.2.2 Failles associées au gisement du 22
Lac Tic 26 1.i'.2.3 Prcpri cté magnétique de l'hémo-
ilménite du Lac Tio 32
~ b .sesIVIMPIENotnaar011a!IieMIBINr^*434kF/draEidiffilliaâiliilG maintammugatimorstniummeS101LL~Yl+M ismisiminisompammanscon
Ix
Page
Chapitre II
MINERALOGIE DU GISEMENT D'HEMO-ILMENITE DU LAC TIO 35
2.1 Introduction . 35 2.2 Description des minéraux 35
2.2.1 Hémo-ilménite 35
2,.2.1.1 Caractères mégascopiques et micro- scopiques généraux 35
2.2.1.2 Composition chimique de l'hémo- ilménite 39
2.2.1.3 Répartition des éléments mineurs dans les phases ilménite et hématite 41
2.2.1.4 Paramètres et composition de l'ilmc- nite et de l'hématite 44
2.2.1.5 Répartition et variation de l'ilménite et de l'hématite dans le gisement 49
2.2.2 Plagioclase 51 2.2.3 Sulfures 54
2.2.3.1 Distribution générale 54 2.2.3.2 Chimie des sulfures 56
2.2.4 Spinelle 57 2.2.5 Magnétite 61 2.2.6 Rutile et anatase . 6' 2.2.7 Chlorite et biotit(1 6ti 2.2.8 Apatite, corindon et zircon 71 2.2.9 Hypersthéae et calcite 75
2.3 Résumé minéralogique 75
Chapitre III
GÉOCHIMIE DES HEMO-ILMENIT.ES DU GISEMENT DU LAC TIO 80
3.]. Introduction ... 80 3.2 Choix et préparation des échantillons 80 3.3 méthodes d'analyse et préparation d'un étalon
d'hémo-ilménite 83 3.4 Chimie des hémo-ilménites dans le gisement 85 3.5 Variations chimiques de l'némo-ilménite dans le
gisement s .... , x17 3.6 Correlations entre les éléments des hémo-ilménites 94 3.7 Synopsis de .a chimie de l'hémo-ilménite 103
Chapitre IV
DIVERS ASPECTS DE LA PETROLOGIE ET DE L'ORIGINE DU GISEMENT
X
Page
DU LAC TIC) 106
4.1 Introduction 106 4.2 Traits métailogéniques du gisement du Lac Tio 106 4.3 Cristallisation et évolution du magma d'hémo-
ilménite 109 4.4 Evolution subsolidus de l'hémo-ilménite 114 4.5 Conclusion 118
BIBLIOGRAPHIE 119
REMERCIEMENTS 124
APPENDICES
I Préparation et analyse de 48 concentrés d'hémo- ilménite
II Préparation et analyse d'un échantillon type d'hémo-ilménite
III Répartition du FeO, Fe203, A1203 et Cr203. dans le gisement
132
136
LIST OF FIGURES
Page
Chapter I
Fi,. 1.1 Windex map showing the location of Lac Allard Area in relation to other anorthosite-gabbro masses in Quebec 14
Fig. 1.2 Aerial photograph showing the open pit workings on the Lac Tio hemo-ilmenite deposit 5
Fig. 1.3 Map indicating the locality of some of the various ilmenite occurrences discovered by Retty in 1941
7
Fig. 1.4 Topographic map of Lac Allard Area
9
Pig. 1.5 Geological map of the Allard Lake Arr3 (in pocket)
Fig. 1.6 Surface outline of Lac Tio mine (Bourret, 19+9) 20
Fig. 1.7 Photographs of hand specimens from the Lac (a,b) Tio hemo-ilmenite deposit 23
Fig. 1.8 .graph relating specific gravity and grade of Lac Tio ore 25
Fig. 1.9 Graph relating the grade of hemo-ilmenite ore with the amount of Si02 and A1203 27
Fig. 1.10 Surface outline of Lac Tio orebody showing the drill holes and the drill sections 28
Fig. 1.11. Strike section of Lac Tio orebody
Fig. 1.12 Dip section of Lac Tio orebody
Fig. 1.:13 Aeronagnetic mup of. Lac Tio mine
Fig. 1.14 Aeromagnetic profile of Lac Tio hemo-ilmenite orebody
Chapter II •
Fig. 2.1 Polished section of an hemo-ilmenite crystal cut parallel to its c-axis 37
XI
291
30
33
34
XII
Fig. 2.2 Polished section of an hemo-ilmenite crystal' tut perpendicular to its c-axis .... .......
Fig. 2.3 Microphotographs of twinned hemo-ilmenite (a to d) crystals
Fig. 2.4 Qualitative electron Probe traverse across an hemo-ilmenite grain
Page
38
40
43
Fig. 2.5 Electron probe traverse across an hematite lamella., showing the relative distribution of Fe and Ti in the two main phases of the Lac Tio hemo-ilmenite
145
Fig. 2.6 Lindsley's curves relating 20 (116) and 20 (024) FeKal with the composition of hematite- ilmenite solid solutions
46
Fig. 2„7 Trigonal cracking in exsolved hematite phase
49
Fig. 2.8 Molecular percent of ilmenite dissolved in Lac Tio hematite phase
50
Fig„ 2.9 Pyrite and chalcopyrite in Lac Tio ore
55
Fig. 2.10 Photomicrograph showing pleonaste spinel adjoining hemo-ilmenite
59
Fig. 2.11 Grain of green pleonaste as seen in trans- mitted light
59
Fig. 2.12 Photomicrograph showing spinel invading (a)
ilmenite along hematite lamellae
6o
Fig. 2.12 Electron probe "X-ray pictures” showing the (b to d) distribution ,f Al, Ti and Fe in (a)
6o
Spinel of the third variety adjoining an hemo-ilmenite crystal 62
Spinel adjoining hemo-ilmenite. The presence of rutile in the hematite free rim may be seen 62
Typical microphotograph showing magnetite replacing hematite lamellae in demo-ilmenite
64
Secondary magnetite replacing hematite 64
Fig. 2.13
Fig. 2.111
Fig. 2.15 (a)
Fig. 2.15 (b)
a s
Fig. 2.21 Microphotograph showing brown biotite in anorthosite
Fig. 2.22 Euhedral corundum included in an hemo- ilmenite crystal
Fig. 2.23 (a,b)
Fig. 2.24
Microphotographs of b persthene in plagioclase
Microphotograph showing calcite inclusions in a plagioclase grain
Fig.
Fig.
3.1 Dip section of Lac. Tio orebody
3.2 Strike section of Lac Tio orebody
88 Fig. 3.3 Percent TiO2 in hemo-ilmenite concentrates
of geological section LM (Dip section) ..
Fig. 3.5 Percent Fe in hemo-ilmenite concentrates of geological sect%on LM (Dip section)
Fig. 3.6 Percent Fe in demo--ilmenite concentrates of geological section JK (Strike section) .. 91
',Iy , , ~J~Î
Chapter III
Fig. 3.4 Percent TiO2 in hemo-ilmenite concentrates of geological section JK (Strike section)
PP'
XIIï
nage
64
66
67
69
70
72
73
714
76
77
Primary magnetite adjacent to a pyrite grain
Inclusions of rutile in plagioclase
Distribution of rutile in hemo-ilmenite
Distribution k>f anatase in hemo-ilmenite
Alteration of ilmenite to anatase. Electron probe pictures
Microphotograph showing chlorite separating hemo-ilmenite and plagioclase
81
82
89
90
Fig. 2.15 (c)
Fig. 2.16
Fig. 2.17 (a to d)
Fig. 2.18 (a,b)
Fig. 2.19 (a to d)
Fig. 2.20
4iv
Eat
Fig. 3.7 Percent Mg0 in hemo-ilmenite concentrates of geological section LM ;Dip section)
Fig. 3.8 Percent Mg0 in hemo-ilmenite concentrates of geological section JK (Strike section) 93
Fig. 3.9 Correlation of Fe/Tî02 with Fe203/Fe0 in analyzed hemo-ilmeni.te concentrates
Fig. 3.10 Correlation of Fe0 with Fe203 in analyzed hemo-ilmenite concentrates
Fig. 3.11 Correlation of Fe0 with TiO2 in analyzed hemo-ilmenite concentrates 97
Pig. 3.12 Correlation of Fe with Fe203 in analyzed hemo-ilmenite concentrates 98
Fig. 3.13 Correlation of Fe with Fe0 in analyzed hemo-ilmenite concentrates 99
Fig. 3.14 Correlation of Fe203 with TiO2 in analyzed hemo-ilmenite concentrates
Fig. 3.15 (104) hematite and ilmenite reflections for samples containing respectively 31.9 and 26.2 percent Fe203 ...
Chapter N
Fig. 4.1 Solvus curve .for ilmenite-hematite solid (a) solution series
Fig. 4.1 Schematic diagram showing the extent of (b) solid solution in the MgTiO3 -, FeTï03 -
Fe203 system
92
95
96
100
102
115
115
Table 2.1 Chemical Composition of Hemo-Ilmenite
Table 2.2
Table 2.3
Table 2.4
Table 2.5
Table 2.6
Table 2.7 Partial Chemical Analysis of Spinel from Lac Tio Ore
Electron Probe Analysis and HematSte Phases
Unit Cell Parameters of Unmixed Hematite and Ilmenite :..,
(116) Reflections cf Unmixed Hematite and Il.nenite
Chemical ComperAtion of Ai orthosi w a from Lac Tio
Distribution of Cu, Ni and Co ir. the Minerals of the Lac Tio Ore
Average.Lac Tio
of Unmixed Ilmenite
41
42
47
48
52
57
58
LIST OF TABLES
Page
Chapter I
Table ?..l Rock Vormations in the Lac Allard Area 11
Tabla 1.2 Chemical Analysis of Brmzite Crystals ...., 14
Table 1.3 Analyses of Ilmenite from the Lac Allard Area 19
Table 1.4 Chemical Analysis of Lac Tio Ore (87% grade) 21e
Chapter II
ÂV
Chapter III
Table 3.1 Major Element Composition of Hemo-Ilaenite. Standard 81e
Table 3.2 Minor Element Composition of Hemo-Ilmenite Standard
85
Table 3.3 Chemistry of Lac Tio Hemo-Ilmenite 36
® . WA +. ~~ ~.~~
- 1 -
A MINERALOGICAL STUDY OF THE HEMO-ILMENITE ORE FROM LAC TIO , OUEBEC
IPITROI;UCTIO:I
The Lac Tic hemo-ilmenite deposit (Fig. 1.1, 1.2) is located about
25 miles north of Havre St Pierre on the North shore of the St.Lawrence
river and represents the largest body of titanium ore of its type now known
in the world. Since its discovery in 1946, several reports and studies have
been made on the geology, mining and metallurgy of the hemo-ilmenite ore.
During this period however, there has been very little systematic work done
on the mineralogy and geochemistry of the ore.
The present work consists of a detailed study of the mineralogy
and chemistry of the hemo-ilmenite ore with the aim to characterize as accura-
tely as possible the chemical and mineralogical variations within the orebody
and to provide fundamental data on the crystal chemistry of the ore.
A diamond drilling program comprising 56 holes and totalling
33,027 feet was carried out on the Lac Tio hemo-ilmenite deposit during 1966
and 1967. The drilling defined the vertical and horizontal limits of the
mineralization and enabled the Quebec Iron and Titanium Corporation (Q.I.T.)
to evaluate ore reserves amounting to arproximately 231+ million tons at a
cut-off grade of 70 percent and an average grade of about 86.6 percent.
The geological and chemical logs from the 1966 - 1967 drilling also provided
general information on the nature of the orebody.
The Lac Tio deposit is presently being mined by the Q.I.T. at a
rate of 2.:3 million tons a year. In the past few years, the mining rate
has been increasing rapidly and it has become important to know as accurate-
ay as possible the nature and chemical variations of the ore through the
entire deposit.. Changes in the composition of the ore would have a direct
bearing on the composition of the two final products, iron and slag.
Should important chemical or mineralogical variations occur in some parts
of the orebod7, their discovery would most likely influence future mining
development programs. For these reasons, a detailed study of the chemistry
and mineralogy of 'a group of diamond drill core samples representing the
orebody k?as initiated in order to provide basic data on the mineralogy
and chemistry of the ore.
The contents of the thesis is presented into four chapters.
Chapter one is a summary of the geology of the Lac Allard Area. It is
based essentially on all published information to date, as well as various
unpublished reports in company's file. The second chapter deals with the
systematic mineralogy of the hemo-ilmeni•te ore, and constitutes an inventory
of the characteristics, mode of occurrence and association of all the
various minerals encountered to date in the ore. The third chapter is
oncerned with the detailed geochemistry of the hemo-ilmenite and is based
on the results obtained frcm the chemical analyses of some 48 high purity hemo-
1..menite concentrates. The fourth chapter attempts to discuss the genesis
;' the ore in the light of available data on the Lac Tio deposit. The
Piy,tnois used to prepare the hemo-ilmenite concentrates and the chemical'
p.:FAIts obtained on each of these concentrates are given in Appendices I
t :rn at the end of the thesis;.
-3 -
CHAPTER I
GEOLOGY OF THE LAC ALLARD AREA
1.1 Introduction .
During the past 30 years, many reports have been published on
the geology of the Lac Allard Area and in particular of the Lac Tio hemo-
ilmenite deposit. These reports are reviewed in this chapter which aims
to summarize the information avai3 ble on the Lac Tio orebody.
More than half of the reports consulted are unpublished and were
obtained from the files of Kennco Explorations Ltd., the New Jersey
Zinc Co. and the Quebec Iron and Titanium Corporation (Q.I.T.). The
remaining published information was obtained from a survey of the lite-
rature (1).
1.2 Location
The region known as the Lac Allard Area is located in the town-
ship of Parker on the north shore of the St.Lawrence River, some 130 miles
east of Sept-Iles, Quebec. Its general location is shown in Figure 1.1.
The principal deposit of the area, Lac Tio mine (Fig. 1.2), is connected
tc the St . L.=..•wrence seaport, of Havre St-Pierre by a 27-mile railroad.
(1) The bibliographic sources principally consulted are the Bibliography of North American Geology, the Anotated Bibliography of Economic Geology and the Bibliography and Index Exclusive of North America.
RE . PIERRE
Fi Vi LAC. ALLARD
AREA r
100 MI.
NEW YORK 200 KM
SORÉL
MONTREA~~
~Pc
•
Figure 1.1 Index map showing the location of Lac
Allard Area in relation to other
anorthosite-gabbro masses in Quebec.
imeat iliG IINgliali
Figure 1.2 Aerial photograph showing the open, pit workings
on the Lac Tio hemo-ilmenite deposit. The hemo-
ilmenite ore is presently being mined at the rate
of 2.3 million tons a year. After primary crushing
the ore is brought by railroad to the port of
Havre St-Pierre where it is loaded in boats and
shipped to the Sorel Plant.
5
_6
1.3 Previous Work and History of the Area
The presence of hemo-ilmenite in the Lac Allard Area was first
reported by J.A. Retty for the Quebec Department of Mines following a
reconnaissance shore-line geological survey in 1941. The ensuing report
(Retty, 1944) describes the occurrence of a number of small hemo-ilmenite
deposit3 along the shores of lac Allard, lac Petit Pas, lac Puyjalon and
lac Bat du Diable (Fig. 1.3). Lac Bat du Diable which does not appear
in Figure 1.3 is located approximately 4 miles southwest of lac Allard.
The showings discovered by Retty were subseçuently staked by
Toronto and Montreal interests and a certain amount of exploration work
was carried out. Kennco Explorations Limited (subsidiary of Kennecott
Copper) optioned the claim groups in 1945 and initiated in the summer of
1946 a detailed exploration program in the vicinity of the occurrences
described by Retty in the hope of finding larger orebodies. This work
resulted in the discovery of a num`fer of hemo-ilmenite deposits, among
which was the large orebody of Lac Tio'11 (Hammond, 1952).
(1) The Lac Tio deposit was actually discovered on June 10, 1946, by two students from Laval University employed on the Kennco exploration party. Traversing from lac Petit Pas southward towards lac Puyjalon, the two stu-dents recorded strong negative dip needles readings at a point approximate-ly mile from the origin of their traverse. Outcrops of massive hemo-ilmenite were observed a short distance from this magnetically anomalous area. Going further south they reached a stream which had cut through the overburden. The stream bed was underlain by glistering black massive hemo-ilmenite. Further south on their traverse they came upon a small lake approximately 1,300 feet long and 100 feet wide. This lake was later named Lac Tio. A very steep cliff rises on the west side of Lac Tio. Traveling along the east shore of this lake, the students were confronted scarcely 100 feet across on the opposite shore, with a virtual mountain ofmassive hemo-ilmenite.
v1} L. ALLAR D
L.PETIT PAS ~
f
a 0 1LMENÎTE OCCURtNCES
SCALE: 2 MILES TO I INCH OR 1:126,720 0 I 2 3 4 5 6 iom~u~------iki
MILES
L . PUYJALON
vommisiessaimommlininilEXIMENIERIENIMINI
Figure 1.3 Map indicating the locality of some of the
various ilmeni:te occurrences discovered by
Retty in 1941 (Retty, 1944) .
8
Fo'.lowing this exploration program and the successful discovery
of the Lac Tio the remaining anorthoaite area west of Lac Allard
was explored ?n 1947 using an airborne magnetometer survey. This survey
did not reveal new deposits; however,st:.ong anomalies were recorded over
all known majcr déposits (Bourret, 1949).
'While exploration was being carried out, the New Jersey Zinc
Co. vas experimenting on a process for producing iron and titanium bearing
:lag from hemo-ilmenite ore by electric smelting. The Quebec Iron and
Titanium Cn poration (Q.I.T.) was incorporated in 1948 for developing and
operating the mine and erecting a smelter to prodess the ore.
The 27 mile long railway that links the Lac Tic deposit to the
port of Havre St-Pierre, the dock facilities at Havre St-Pierre, the
Smelting Plant and receiving dock facilities at Sorel were built in 1948
and 1949.
The mining started in 1950 at the Grader orebody, now idle, but
from which over 200,000 tons of ore was extracted. Sine:. then Q.I.T. has
been ^fining the Lac Tio hemo-ilrrsenite deposit.
( 1.4 rlyalaa. GGee°. ai,fly
Along the coast, and north of tue westwa: d flowing portion of
the Romaine River, is a flat coastal plain known as the lowlands (Fig. 1.4).
The lowlands are underlain by flat-lying Paleozoic limestones and consist
of open muskeg dotted with many shallow lakes and ponds. The ground between
the Romaine and Puyjaton Rivers is flat and sandy and represents parts of
an old marine terrace.
-9-
uin Chan 'ii; ~~/• iaure St-Pierre
r-t • 'Havre- St-Pierre v~ . ••••••, EsWmo ~ .
Island /
Fright I Gr n, !~ 1
ee
Gult i
~
:• --•...~._ . . - ~: rilobit: t:~j:::?'.;; ;`;~_,,,._.7i.. •a•~;~~ Bav
f{[ty. • ..• ~ • . t~~..
t P 'K
,I/t
1T3 .Fi ay: .
• I < B~ • s
,,.,t a ,~LISt•Chgrlr— s - '~ msannarsomonninggi amennsis on
\, Sea Cow Island
Wnlrus I
0 5 1G _~asll^n • 5=14 r78giFar _~_...p
MILES
Figure 1.4 Topographic map cf Lac Allard Area.
(Map 12 L, Mines and Technical Surveys, Ottawa.)
-10 -
Approximately 3 miles from the coast, the terrain rises rapidly
to form the uplands. Viewed in a general way, the surface has the appear-
ance of an ancient peneplain with the horizon presenting a general uniform-
ity of summits in all directions. In detail, however, the surface is a
much dissected platen with precipitous cliff faces and well entrenched
valleys. At Lac Allard, the highest summits reach 1,300 feet above sea
level. The maximum relief is approximately 800 feet; the average relief
is between 200 and 300 feet. The uplands are underlain by igneous and
metamorphic rocks of the Grenvflle Province.
Glacial erosion has been an important factor in shaping the
present topography. The larger lakes occupy north-south depressions
approximately parallel to the direction of ice movement. Many small lakes
lie perched in irregular depref,sions at higher elevations and the second-
ary drainage sy.-gem has been disorganized to a large extent.
The area is drained by the Romaine River system which head
lies near the Quebec Labrador boundary. The Romaine flows in a well en-
trenched valley, with numerous rapids and falls.
Throughout the uplands, a thin cover of boulders and soil rests
on bedrock and supports a stunted growth of spruce, balsas and pine. Many
large glacial erratic., most of granitic in nature lie strewn about the
surface.
1.5 General Geoloçy
The consolidated rocks of the Lac Allard Area are of Precambrian
age and comprise a series cf metamorphic and igneous rocks that belong
to the Grenville Province (Fig. 1.5, in pocket). The formations that
underlie the area are summarized in Table 1.1.
Table 1.1
Rock Formations in the Lac Allard Area (Retty. 1941 )
Pleistocene and Recent
Clay, sand, gravel
Precambrian Grenville Province
Intrusive rocks
•
Diabase Lamprophyre Gabbro, metagabbro Porphyritic granite, horn- blende granite, pegmatite
"Morin Series" of Retty, 1944
Arcrthozitic dykes Anorthosite with coarse pyroxene crystals (Hargraves, 1962) Anorthosite, anorthositic gabbro, £ _narthnsite rich in ilmenite.
Metasedimen- tary rocks
"Grenville Series" of Retty, 1944
G;uartzito. quartz-biotin. F ;aes, quartz-hornolende rne .ss, garnetiferous gneiss, amphibolite, garnetiferc;ur: graphite schist, injection gneiss
12
1.5.1 "Grenville Series" of Retty (1944
Rocks of the "Grenville Series" are represented by quartzites,
quartz-biotite gneiss, quartz-hornblende gneiss, garnetiferous gneiss,
and small patches o: amphibolite and garnetiferous graphite schist. These
rocks occur abundantly along the Romaine River between the First East
branch and the Second East branch. Numerous outcrops are also found on the
shores of Forget lake and in the adjoining area to the east.
1.5.1.1 Quartzite
The quartzites are common in the region of Lac Allard. The rock
is ordinarily composed of small white and vitreous grains of quartz and
small proportions of biotite, magnetite, and in some places disseminated
garnet.
1.5.1.2 Hornblende Gneiss and Biotite Gneiss
Well banded hornblende gneiss and biotite gneiss are also abundant
in the region of Lac Allard. They are composed principally of quartz, horn-
blende, biotite, orthoclase and plagioclase in varying proportions.
Apatite, zircon, magnetite and graphite are the usual accessory minerals
found in the gneisses.
1.5.1.3 Garnetiferous Gneir
A large part of the "Grenville gneiss" in the Lac Allard region
contains in afiditiou to quartz, some 15 to 20 percent garnet with small
quantities of albite, graphite and biotite. This variety of gneiss is
also rich in hornblende.
1.5.1.4 Less Common Rocks of the "Grenville Series" in the Area
Among the less common rocks observed by Rates 5-n the region,
are graphitic garnetiferous schists, greywackes, amphibolites, migma-
tites and injection gneisses.
13
1.5.2 "Morin Series" of Retty (1944),
The most important lithological unit in the Lac Allard region
(Fig. 1.5, in pocket) is anorthosite and related rocks. They were grouped
as "Morin Series" by Retty op. cit. and comprise anorthosite and associated •
rocks such as anorthositic gabbros and anorthositic dykes. As shown in
Fig. 1.5 (in pocket) in the Lac Allard Area, these rocks extend for more
than 70 miles in the southwest direction and form a zone approxim.tely
20 to 30 miles wide.
1.5.2.1 Anorthosite
Anorthosite is the major rock type in the vicinity of Lac AL:lard.
As a rule, it is massive, coarse-grained and contains 95 percent or more
plagioclase. In fresh exposure, it varies in color from pale gray to pink
to somewhat resinous green whei:it contains more than 5 percent ferro-
magnesian minerals. In weathered outcrops, the anorthosite is usually
gray to chalky white. The equig:aniiar varieties of anorthosite have grains
sizes that range from 3 to 6 mm and is characterized by sporadic coarse
plagioclase phenocrysts 2 to 35 cm long. The phenocrysts are similar in
composition to plagioclase of the enclosing matrix (Hargraves, 1962).
In thin section, the texture of the anorthosite varies from
hypidiomorphic to allotriomorphic'granular, and the plagioclase grains
(An 40-52) range from 3mm to 12mn in size. Approximately half the 25
thin sections examined by Hargraves (1962) showed evidence of cataclasis
as indicated by scattered relics of larger crystals exhibiting undulatory
extinctions, bent twin lamellae and fractured margins. The finer-grained
material surrounding the deformed fragments and locally constituting the
entire rock, is anhedral and displays intricately sutured grain bound-
aries, suggesting recrystallization of crushed material.
-11+-
1.5.2.2 Anoruhosite with Coarse Pyroxene Crystals
Hargraves (1962) noted in several locations,zones of anorthosite
characterized by coarse crystals or cloth of crystals of greenish bronzite.
A chemical analysis of typical pure bronzite, separated from samples col-
lected at Lac Tio is given in Table 1.2
Table 1.2
Chemical Analysis of Bronzite Crystals
(Hargraves. 1962),
SiO2 51.81 Na20 0.01
A120 2.80 K20 0.00
Fe203 2.09 H0♦ ~ 0.07
Fe0 17.27 H20 0.03
MgQ 21+.18 TiO2 0.52
CaO 0.83 Mn0 0.29
Total 99.90 Calculated formula En 69 Fs 31
1.5.2.3 Ilmenite Rich Anorthosite
The ilmenite rich anorthosite (oxide rich norite of Hargraves,
1962) is medium-grained seed slightly foliated or gneissic. Tie essential
constituents of the rock, in paragenetic order, are plagioclase, pyroxene,
a, atite and oxide. Despite variation in the relative proportion of these
constituents, the mafic fraction rarely constitutes less than 50 percent
by weight of the, rock. Sulfide, largely pyrite with minor pyrrhotite are
constant accessories, and secondary biotite is sporadically distributed.
A study of thin and polished sections of the oxide rich noriti.c
anorthosite (Hargrave, 1962) reveals that it contains the follovbug
15
mineralogy :
Magnetite 10% Hemo-ilmenite 10% Pyrite with minor pyrrhotite
2%
Plagioclase 30-40% Hypersthene 20% Augite 5-10% Biotite 2-3% Spinel Traces Apatite 5-10%
/1
1.5.2.4 Anorthosite Dykes
Retty (1944) describes the occurrence of three anorthositic
dykes cutting the anorthosite massif. These dykes generally have a
composition identical to that of the anortht.site itself.
1.5.3 Granitic Rocks
The rocks are usually coarse-grained and exhibit a porphyritic
/1 texture. In those rocks, the quartz is ordinarily opalescent and the
mafic minerals, hornblende and biotite, are visible to the naked eye.
In thin section, apatite, zircon and magnetite can be recognized as
accessory minerals.
Retty (1944) has noticed that the rock is locally poor in quartz
and could be more appropriately named syenite.
1.5.'4Dio r ite,, Gabbro and Metagabbro,
Diorite, gabbro and metagabbro have also been noted in the Lac
Allard Area (Betty, 1944). Since these rocks are not very common in the
re:pion, they will not be discussed furti:er in the thesis.
1.5.5 Pleistocene and Recent
In the lowlands, the traces left by the glaciation have been
washed by the invarion of the Champlain Sea and covered by sediments.
Sand, cls;y and gravel are the win constituents of the marine deposit.
- 16 -
In the Lac Allard region, the U-shaped valley of the Northeast
Romaine River constitutes the main evidence of glaciation. The sand and
gravel deposits along that river are considered to be of glacial origin.
Some glacial striations along the shores of Forget Lake indicate
that the movement of the ice sheet was from north to south. However, in
the vicinity of the Bernard and Northeast Romaine Rivers the striations
seem to indicate a south-west movement.
1.6 Structural Geol
There is much evidence that the area has been subjected
to large scale structural disturbances over long periods, as indicated
by the highly contorted and metamorphosed nature of the Grenville type
rocks and the strong fault and joint systems developed within the
aaorthosites (Bourret, 1949). In the vicinity of Lac Allard, the anortho-
site is text by numerous steeply dipping to vertical joints and faults.
They strike north or northeast and represent faulting of the normal
type in which the hanging wall block has moved down relative to the
footwall block. These features are everywhere apparent in the topography,
giving rise to preèipitous cliff faces. In many instances, they appear
as a series of steplike structures along the hill slopes.
Some of the major faults have been traced for several miles,
and Borne continue without appreciable change in strike beyond the
anortt.osite body and into the surrounding granite. These fractures are
open and obviously younger than all of the Precambrian rocks of the
area.
It is usually impossible to determine the relative displa-
cement in an intrusive rock of uniform composition such as anorteosite.
However, one major fault has been studied in detail in the vicie ity
of the Lac Tio deposit, where it appears to have been an important factor
in the preservation of the main orebody. Detailed exploration has shown
that the erebody is in the form of a large, tabular, relatively flat-
lying mass. It can oe reasonably ass',.med that the attitude of the ore
was the same at the time of deposition. A north-south fault, with a „teep
dip to the east, cuts through the middle of the deposit and has moved
the east side of the orebody downward, a vertical distance of approximately
300 .feet.
There is no apparent horizontal movement. As a result of this
fault, the ore in the east part of the deposit was preserved from erosion
and Pleistocene glaciation.
1.7 Economic Geology
1.7.1 Introduction
The economic interest of the Lac Allard region is primarily
centered on the deposits of ilmenite it contains. Although Retty (1944)
noted the occurrence of chalcopyrite mineralization in paragneisses in
at least six localities, he principally emphasized the potential of the
region for possible ilmenite deposits. His discovery of several ilmenite
deposits along the shores of Lac Bat-du-Diable, Lac Allard, Lac Petit Pas'
and Lac Puyjalon (Fig. 1.3) was a key factor that initiated the subsequent
development of the region. The largest deposit of the area, the Lac Tio
deposit was discovered in 1746 following exploration work undertaken by
Kennco Exploration Ltd. Other deposits of less importance were also out-
lined by this work; such is for instance the Grader Lake deposit from
wh:+.r 1 200,000 tons of ore were extracted in the period of 1950-51.
"11 of the ilmenite deposits of the area are associated with
anotthositic rocks and probably have closely related origins. They may
be classified structurally (Hammond, 1952) into thr:e types on the basis
of attitude and shape of the oxide masses; these are, flat'-lying tabular
bodies of large areal extent (Lac Tio deposits and satellites), steeply
dipping dyke-like bodies (Puyjalon deposit) and lenticular masses irre-
gular in shape. There ere in the Lac Allard area six ilmenite deposits
which respectively contain a million tons or mc.r
-. 19 -
largest and most important is the Lac Tio deposit which is presently
mined at a ratc of 2.3 million tons per year. The deposits of the Lac
Allard region contain ilmenites of similar composition. The original
analyses of the ilmenite phase of the ore from six deposits discovered
by Retty in 1941 are presented in Table 1.3. Their high iron content relative
to TiO2, similar to that of the Lac Tio deposit, indicates that they are
ilmenite-hematite exsolution mixtures and are appropriately referred to
as hemo-ilmenites (Buddington and Lirisley, 1964).
Table 1.3
palyse:, of Ilmenite from the Lac Allard Area
(after Rett- . 1944)
(5)* (1) (2) (3) (4) (6)
Fe 45.01 41.18 45.08 43.33 43.41 43.64 TiO2 32.24 36.00 35.98 35.89 38.14 37.79 Si02 1.36 2.57 1.78 0.96 0.87 1.42 P - - - - 0.05 - S 0.14 0.47 0.16 0.16 0.16 0.11 V 0.02 0.08 0.03 0.03 0.03 0.19
1.7.2 Me Lac Tic Dep o it
The Lac Tio deposit is an extensive body of hemo-ilmenite lying
roughly half way between Lac Puyjalon and Lac Allard (Fig. 1.5, in pocket)
approximately 23 miles northeast of Havre St-Pierre on the; north shore of
theSt.Lawrence River. As determined from surface exposures and diamond
drilling, the depo,it is 3600 feet long and 3400 feet wide and occupies
an area of 134 acres (Fig. 1.6). The maximum elongation of the deposit
' These numbers refer to the original locality number in Retty (1910:;
(See Fig. 1.3).
LAC GRONDIN
NORTHWEST ORE BODY
:. GISEMENT NORD-OUEST
.. MAIN ORE BODY
GISEMEN'i' PRINCIPAL „
LAC TIO
CLIFF ORE BODY
GISEMENT CLIFF
0 500 10~0 1500 F E DS
~ i 1 0 250 500 M
LAC ANO
- 20 -
Fig. 1.6 Surface outiille of Lac Tic) mine (Bour•~et, 1912)
- 21 -
lies almost due north, however, its plan expression is irregular with
large lobes of ore extending east and west. Thr:re are also wide variations
of elevation in the area underlain by massive hemo-ilmenite. A compara-
tively level valley occupies the central part of the deposit and extends
to the snithern end of Lac Tio. On the west side of this valley the terrain
rises rapidly and reaches an elevation as high as 140 feet above the
valley floor.
For convenience the Lac Tio deposit is generally considered by
the Mine personnel as consisting; of three parts (Fig. 1.6); the Main orebody,
the Northwest and the Cliff orebodies. Although the Cliff orebody is
separated from the Northwest orebody by a large block of barren anortho-
site, it is undoubtedly closely related to it in origin.
The Main orebody is by far the most important part of the
deposit with respect to size and thickness. South of Lac Grondin it
occupies a large crudely recta:irular area from which a smaller triangular
portion protrudes and extends south along the east side of Lac Tic). The
western edge of the Main orebody abuts against a north-south trending
and steeply dipping fault along which the eastern block has moved down-
ward relative to the western block.
The Northwest or:-oody which lies on the west side of this fault
is a thin flat-lying body from 25 ;o 200 feet thick and dips gently to
the east.
The Cliff orebody (Fig. 1.6) is a broad, flat-lying, tabular
mass of hemo-ilmenite that rises sharply above the western shore of Lac
Tio. It is crudely elliptical in plan expression and measures 1240 feet
in a north-south direction and 740 feet in the east-west direction. The
-22-
average thickness of the crebody is approximately 200 feet. The eastern
part of the orebody is well exposed along the shore of Lac Tio. The ore-
body has a relatively uniform floor in sharp contact with the underlying
anorthosite and dips gently to the east. Drilling,on the west side of Lac
Tio,indicates that the ore extends flatly under the anorthosite wherA it
thins rapidly and pinches out.
The larger part of the ore of the Lac Tio deposit is concen-
trated in the Main orebody. Blocks and/or inclusions of anorthosite, as
well as zones of disseminated hemo-ilmenite are present throughout the
deposit. The blocks of anorthosite vary greatly in size, shape and orien-
tation. They are presumed to represent blocks of country rock engulfed or
included in the ore during its emplacement. The zones of disbeminated hemo-
ilmenite commonly occur as subhorizontal bands within the massive hemo
ilmenite.
1.7.2.1 General Mineralo•. and Chemist of the Lac Tio Deposit
Although the Lac Tio or more commonly the Lac Allard ore is
usually referred to as ilmenite in the literature,it actually consists of
a microscopic intergrowth of hematite in ilmenite. Such ilmenites are
called hemo-ilmenites (Buddington and Lindsley, 1964). The ore is a
dense, black, mostly coarse-grained aggregate of thick tabular crystals
of hemo-ilmenite (Fig. 1.7a, b). The specific gravity of the material
classified as ore ranges from 4.46 to 4.9. The relation between grade(1)
and specific gravity of the ore is shown in Fig. 1.8. Plagioclase in
(1) Grade is defined as t'le sum of FeO, Fe2C3 and Ti02.
-23-
(a)
Pia- 1-7P-- t Photographs of band specimens from the Lac °iic hemo-ilmenite deposit : (a) X 1/2 (b) X 1.
- 21. -
amounts varying from 3 to 12% and accessory amounts of pyrite, sninel,
biotite, magnetite and hypersthene are generally found in the ore. Chalco-
pyrite, millerite, rutile, zircon, chlorite, corundum and anatase are
also present in very small amounts. Detailed information on the nature
and occurrence of these minerals are given in Chapter II.
The ore generally mined by G.I.T. has a grade of 87%. A
typical analysis of this ore is given in Table 1.4.
Table 1.4
Cheniiccal Anal of Trac Tio Ore (87'4 Grade)
?re i Rht `'1 ...~~~
Ti02 34.2 Idn0 0.16 Fe0 27.5 S 0.3 Fe203 25.2 PIa20 and K20 0.35 Si02 4.3 P205 0.015 A1203 3.5 Cu 0.006 CaO 0.0 Ni 0.026 i+iRO 3.1 Ga 0.003 Cr203 0.10 Co 0.015 V205 0.41
Lister (1066) has studied the chemical variations in the Lac
Tio orebody. The results of his work indicate that there is no regular va-
riation in the Fe/Ti02 ratio in the orebody. However, localized chemical
variations were observed. In the .massive hemo-ilmenite portion of the
deposit, the amount of Cr and V decreases upwards while that of Mg increases.
These trends would not seem to be present in the eastern or layered sections
of the ore sheet. The Mn content cf the entire deposit is unusually low.
The chemical composition of the ;i*ero-ilmenite crystals corresponds arrnro-
ximately to 30 percent hematite acid 70 Percent magnesian ilmenite.
lowest amounts of Mg and the highest amounts of (Fe 4* Ti) were found in
ar.B IAt.ta.e..lmmo wn ..wlwa. c.alw a.l alv ~s~ aua
The
• ••
•
•
• • ~• —, 4.6
•~
• 4.4
42
4.0
3.8
5.0 •
4.8 • •
42
4.0 M
U II 3.6 &6 V w a N 3.4 --' 3.4
3.2 3.2
à0 3Si
I 1 . i ~ .._.~,.._~ . ! ~ i 1 ~ ___~__ 50 60 70 80 90 100
GRADE •0'' ORE ( % Fe203 + % Fe0 + T102 )
Fig. 1.R Graph relating s(cific gravity And grade of liac Tic) ore (New :Jersey Zinc) .
iiiimminiormimammumium umummeimaxr.ans•sr. ~~•. ~~~~m~• tlp~arr.~
-26-
hemo-ilmenites from the upper part of the layered section of the sheet
(Lister, op. cit.).
Compared with the hemo-ilmenite from the deposit, the hemo-
ilmenite from the anorthosite host rock has a lower minor element content
with the exception of manganese.
The relations between grade and the amoun'. of Si02 and A1203 in
Lac Tio ore is shown in Fig. 1.9. It is interesting to note that the trend
for the SiO2 values extrapolates to zero at the maximum grade ore while
the alumina values extrapolate to about one percent. This is interpreted
as indicating that the pla?ioclase (silicate) content of high grade ore
may approach zero but its spinel (aluminate) content may be as high as 2%.
Figure 1.10 shows a plan view of the Lac Tio orebody where the
diamond drill holes and sections are indicated. The numbers (e.g. T-91-6)
correspond to the locations of the holes drilled in the summers of 1966
and 1967. Figure 1.11 is a strike section corresponding to the line J-K
on Figure 1.10. Figure 1.12 is a dip section corresponding to the line
L-M on Figure 1.10. These sections are from Lister (1968).
1.7.2.2 Faulting of the Lac Tio Orebody
Three faults trarsect the orebody in the mine area (Lister,
1968). The most important fault forms the boundary between the Main and
the Northwest orebodies (Fig.l.6).Scissor-like movement along this plane
would appear to have raised the west block approximately 300 feet at the
north end of the orebody (Hammond, 1952). The displacement along this
fault decreases towards the south and the fault seems to terminate within
the Cliff orebody.
20
18
16
14
n) 12 o
10
o M 8 0
N
4
2
60 70 80 90 100
412 03
- 27-
GRADE OF ORE
Fig. 1.9 Graph relating the grade of hemo-ilmenite ore with the amount of SiO2 and Al20. (New Jersey Zinc).
000N
~
LEGEND
MORE THAN 70% ILMENITE
ILMENITE ( 30-70 %)
DDH Pt1 AN SCALE I = 600'
k•: : .;: •ï : :~. 4 "'I+ (' 0,000 N f::::::: ; : ~ I ~::: T- 99-8 ~' :.a~ 1 LAC
1Q.§7-9• '• ?~ ~~.:' A .~~` .....17.,.....-. , ~
97 '+: %::; : ~.. _ ~:: •: • ~. T- ~'• T 97-1 ••T-97-2,.T-97- 'Y-9y-5: :; ' • •~;. ::. g~ ::. • F:~'•: ..~~ I.;:::• \ •:4~..::::::•:.
/1-95-6 ••:•:-».....:::. %XT-95.3 T-95-1 T-95-2
--+6rtir%• --- • - - • - 0
T-92-8 `
%z S \
i:::::::: .....\.... ST.-9 1-1 T-91~ ~ _ _ i:::::,;:: ~• • - ... • >~ • 9 Oo~ NORTHWEST ~ st.......... i
' OREBODY T- 87-11 T- 87-10 i
\ I 0 0 T-87-9 T-87-5
. •T•-- • r----,. ~ •
S .......\ / a. a.
1-43 -7 :....*:•:::•:•:•;:?::;::. •:'
0 ---s~;~ --~ _...2.;.:. ,` ~••--
~_::~:• I
~•/'•T~~~
\°•' ; 9-5 —Q—. ~
~ ..~
-~f ~•• ••
F'' CLIFF • ~~ 1+ '~~y:!!•T `:•'~ OREBODY •~'~~ ~~
'••~•:~ TI-13;~. T-71-7 ;;r; •..r,^..~'i~~
e
~~• - ••~•e_1:1i1 I:,;r
' ~ •;:; •
': îr~ T:~::::, • ~'~:_:.E• ~~••• :; .,~,..::',.
• . Y,.. ~•i;~r ~ T-67-2:: ~~e~h-6 T1
• . • ~ ~:: : ~
... • . . ~ 64-1 T
•
0 DRILL HOLE ( 1967) • DRILL HOLE( 1966)
DRILL SECTION
!~_• L•~/
i>1- 6 1-79-7 - T-79-2 ~
T-75-1 T-75-3 0
:: : :•: r ..1.:.:::.:::,.. ~ MA I N ~ ji v'' ::.
~'' T 8.3-2.... _ T-83-I T- Q 3'~• `<`='' ~~k•
`
'f'•,L ~ ` •'~' \:~S
T-79-3 T-79-1 •
T
T-75-2 . T-75-5
h•-9T ï~ ~~ :9 T-95••4
--- T-95-5 -•- - n--0 - .~N~
`,~'i1 r.r.` !:'••]Y•~:~,~' 15;4:? '~•'-T91 T-9~-6 'i;~~r91-5 T- 901-7
; ~:v};,- • — ,~ ,~ f:u a~..~e •,~ ~ ;:~.~. ; .1_~r~~ .ti.'
.~1F6.. {i~P
T-87-6~~:r,T-87a T-87-3 ~*~`T-87-1 ._ • ;,,~ • — - _— • _
....,,....4...v57:„....______.
-~st±3~- 0 •~-,i,Wr . .. rr~~
OR :Et•;?B~O~~~// ~~;-~`43 -%!;:7~
,'~~'`% T-83- 4;~;;J
O T ',
GRONDÎN
Fig.. 1.10 Surface outline of Lac Tiso orebody showing the drill holes and the drill sections (Lister, 19(3).
11111E111111=1121111111111111
~
~ I
T-64-I
..
' _: — / .~ ~I ;;v`•
~ i • ï
: v
1
7. i 1 1 I
/ ~~
.
.,.~~
., -.:~ : i % • ; f / t / / -""..14::.
•. .- a+ ,.'-: :. / t / .. ti\'\i ~
1 ~ \
1 / ,I t'/ \ ~ • / - \ ~~ i. ~t
/ t ! ~ /. / / \ t \ _ ' 1 ~ \ ; ; f / I , f ~ 1;~:;
1 , e l. t it / 1 t ~ / 1 • • / 1 ~
/ I I 1' \/ 1 ti t/ `/ 1
/ 1 1 ....
~ -- —? ••••~ ~ •V•••.. —.,_---- T~7
---<:::: 2 T-71-8 t--.r r •~ ~ —..-3 ~1
—. c :::: — -- ..... ► --T•75-2 T-79 fi 7.313-1 --., .~
~k i~, _•~ :I'„•~PRESENT SURFACÉ T-67—E
. . . . : .t•. . . . . ... . _ . . .LS - _ •`itYi . •.T r7'i Vû~.-Ji•
• /.
p I - 1 / 1 . t •~ 1 t . / 1
1--.4.':'."' :;{•: / ✓! i~ /
tl; ~ /
. t v.~`L•ü ~~' .t:iYé~'~' ~'Ÿ / t \ / \.~1~ / . I \_ '' t I ' I
'/ / 1~ J/ , I/ I \~ 1 1 ! J I~ ~
.-
t ~ / - \•1 . ~ ~ ` !V 1 / ~ — i f \ f ♦ / . I 1 1 —• t• .. ~ ~ — 1 ~ I
~ I I ..t 1-500
'~— T--91 4—.. F95-9 —.,_ _..
• 1..GRON 1N
~ . 500 500
LEGEND
> 70 % HEMO-ILMENITE
30-70 % HEMO- ILMENITE
ANORTHOSITE
LAKES
LAC TIO ILMENITE DEPOSIT
SCALE 1"= 600' DATA BY G.E. LISTER
rig. 1-11 Strike ;lecr' ,ion of Lac Tio orebody (Lis G r, 1968).
intanaminmenseartilimmilimill111101111MIAMMILMOMEIBRAMMEISIIIIIIIIII0111k INEVNIIIMENE
M
T797 PRESENT SURFACE T79-6
T-87-9 T-833 T-83-4
I %RESEN.F. .- ^ ^ T-92-8
SEA LEVEL
1. r x iv::;:: :~::;: , , S(/RFACE ~ v ,~:.; ::::;: :Tw:~t::::;::: v~~` ..:•:•:•:::"...‘
r• 7 ( < 7 V• r
500 > v V V % V
< ç -7 1 < - ^ L A
L
^ ~_
RISEN V . < '
L.< '::::~ : _a..~•~,;~ :;;::~~:: ~ , ~;,• , ~~:y~~:: ~ A n ~.
~`;•,';•ri:r`, . SEA LEVEL
500
500
„..:~..::~ •: .~ . :Ï Î`. •~s.►,. +: :s .:~+.+: R d
L ‘,0 T• G t , J J J
., n
LEGEND
C:1 > 70 % HEMO-ILMENITE
30'70 % HEMO' I LMENÎTE LAC TÎ0 ILMENITE DEPOSIT
am ANORTHOSITE SCALE I": 6001 DATA BY B.F. LISTER
Fig. 1.12 Dip section of Lac Tio orebody (Lister. 1968).
r'9>sv>IisRismiF3misi i~~~ lint=Îi1111 :1?:
11111111111111111101111111111111111W111111111WMANIEMENIMEW
- 31 -
Another fault extends southward from the southern tip of Lac
Grondin. At Lac Grondin, scissor-like movement along this plane has
raised the east block less than 100 feet above the west block. Displace-
ment along this fault decreases further to the south; no displacement is
apparent at a distance o2' approximately 1000 feet from Lac Grondin.
*The third fault was mapped in the pit, where it extends north-
ward from the west side of Lac Tio. Displacement of the base of the ore-
body along this fault seems to be minor. The southern extension of this
fault is thought to separate the Cliff orebody from the Main orebody
(Lister, op. cit.).
Chloritization over widths of a few inches is generally evident
where steep faults cut the orebody. The feldspar and faulted anorthosite
has been bleached, reddenet., saussuritized or chloritized. In very few
cases, minor hydrothermal leaching of iron from hemo-ilmenite along the
faults, has given rise to zones of brown, r>>tilized hemo-ilmenite for
width: of a few inches (Lister, 1968).
These faults are part of strong north and northeast trending
linear features, that are evident in the field and on aerial photograrns
of the area (Lister, 1966).
Topographic offsets along these lineaments suggest that these
are faults with relatively minor vertical displacement, probably less
than 50 feet in most cases (Lister, 1968). These faults together with
the three faults described, would appear to be àensional features related
to post-ore• intrusion relaxation and por.Fibly related in part to the cooling
of the hemo-ilmenite body (M.ster, 1968) .
1.7.2.3 A'I netic Pronert of the Lac Tio Hemo-Ilmenite
The "magnetic expression" of the Lac Tio orebody soon attracted
the interest of geophysicists. Contrary to magnetite-ilmenite orebocli es
common to anorthositic terrains which characteristically give rise to
strong positive magnetic anomalies, the Lac Tio hemo-ilmenite appears on
aero-magnetic nap as a conspicuous "magnetic low".
Figure 1.13 is an aeromagnetic map that ewers the Lac Tio area;
the surface outline of the orebody has been superimposed on the magnetic
data (Hammond, 1952). A magnetic profile (Fig. 1.14) illustrates the
strong negative anomaly associated with the Lac Tio orebody. The massive
hemo-ilmenite deposit gives rise to sharply defined negative anoaal4es.
Their magnetic intensity lies some 3500 gammas below the average magnetic
intensity of the surrounding rocks. The strong negative anomalies are
believed to be the result of negative polarization of the orebody itself
(Carmichael, 1961). A detailed study cf some hemo-ilmenite specimens by
Carmichael (1959) has shown that the remanent magnetization is mainly due
to the hematite lamellae.
GRONDIN LAKE
-'C
50~ ~
Ip00 1,5J+u~E~.m 'om.
ANO LAKE FEET
LEGEND :
o o oo , o SURFACE OUTLINE OF LAC TiO MINE.
AEROMAGNETIC CONTOUR—INTERVAL 500 GAMMAS.
Fig. 1.13 Aeromagnetic map of Lac Tio Mine (Hammond, 1952).
gammas
1500
1000
—500
—1000
—1500
2000— 1200 FT
liMENITE-HEMATITE
ANORTHOSITE
1 • 411/••••••.• ••••••P
4•11111••
500
o
An
400 FT
2 0 1 I
0 2 3 4 5 KM
3 MI. 1
Fig. 1.14 Aeromgmetic profile of Lac Tio hemo-ilmenite oreboilz (Botrret, 1949).
- 35 -
CHAPTER II
MINERALOGY OF THE LAC TLO 1iEMO-IL ENITE DEPOSIT
2.1 Introduction
The Princiral minerals identified to date in the Lac Tio hemo-
ilmenite ore-are hemo-ilmenite and gangue minerals mainly represented by
plagioclase and accessory or trace quantities of sulphides, sninel,
magnetite, rutile, anatase, chlorite, biotite, apatite, corundum, zircon,
hynersthene and calcite. T'ne aim of this chapter is to describe these
minerals, placing special emphasis on their composition, occurrence and
association.
This part of the study is based principally on the results of
microscopic examination of polished sections and polished thin sections
obtained from approximately 40 snecimens. X-Ray diffraction, X-Ray
fluorescence and electron microprobe analyses were used to identify
the minerals and determine their compositions. The occurrence and charac-
teristics of the various minerals are illustrated with the hein of micro-
rhotograrhs. Electron microprobe traverses and "X-ray Pictures" are
also used for illustrating the distribution of elements within particular
mineral chases.
2.2 Description of Minerais
2.2.1 Heuo-ilrnenitr,
2.2.1.1 General Megascoric and Microscopic Characteristics
Typical Lac Tio ore consists of a dense aggregate of coarse-
grained black hemo-ilmenite (Fir. 1.7a, b). Monomineralic specimens have
- 3E -
a specific gravity of 4.8. The hemo-ilmenite crystals are tabular or
pellet shape and lie oriented roughly parallel to the attitude of the
ore sheet (Hargraves, 1959). Some hemo-ilmenite is also found dissemi-
nated in the surrounding anorthosite rock. A large mass of disseminated
hemo-ilmenite in anorthosite occupies the northeastern part of the
deposit'.
Under the microscope,the mineral is seen to consist of a regular
microscopic lamellar intergrowth of ilmenite and hematite. Two group,3
of hematite lamellae may be seen in all crystals examined. Figure 2.1
is a typical microphotograph of an hemo-ilmezaite crystal cut parallel
to its c-axis. This photograph shows clearly the hematite lamellae in the
ilmenite host. The hematite lamellae fall into two distinct size ranges,
one of large and some intermediate lamellae, and the other of very
small lamellae. The large and intermediate lamellae range in length
from 1 to 10 mm and in thickness from 0.005 to 0.02 mm. The larger
hematite lamellae are seen to host minute lamellae of ilmenite. The
small hematite lamellae are roughly 5 to 10 microns long, 1 micron
wide and 0.2 micron thick (Carmichael, 1961).
The hematite phase appears as small circular pods or discs in
sections cut perpendicular to the c-axis of hemo-ilmenite crystals
(Fig. 2.2). It is evident from microscopic observations that the hema-
tite phase is intergxown in the (001) basal plane of the hemo-ilmenite
host crystal. Such a rely:.onship is expected on structural grounds
for ilmenite and hematiae are isostructurai compounds (Gruner, 191,9).
Intergrewth of this type appears to be the result of unmixing from a
hemo-ilmenite solid solution because the crystal may be rendered homo-
geneous by heating to high temperature (Carmichael, 1961).
-37-
Figure 2.1 Polished section of an herno- ~ilrnerite crystal cut parallel to its c•-axis (X.00).
white : hematite phase gray : ilmenite phase
.;Figure 22 . Polished section of an'hemô-::lmenite crystal cut perperdswule,r, to its (X100).
white : hematite phase
gray : ilmenite phase
-39 -
Twinning of the hemo-ilmenite crystals wt.s observed in all the
specimens examined. In general twinning is not abundantly developed and
the samples do not contain many twins. However, a few specimens display
excellent (1010) twinning. The best examples of twinning encountered
during the microscopic examination of Lac Tio hemo-ilmenite samvles
are shown in Figures 2.3 a to d. The distortion of hematite lamellae
by twinning is particularly evident in Figure 2.3a; it indicates that
the exsolution of the hematite lamcilae is older than the twinning.
None of the crystals examined showed major distortion of their twin
Manes. This suggests that the Ln.c Tio deposit was not subjected to any
major deformation after its.emnlacement and consolidation.
2.2.1.2 Chamica7.Composition of H,mo-Ti menite
Although the chemistry of the hemo-ilmenite is dealt with in
detail in Chapter III, it is arrronriate at this point to present the
average chemical composition of the Lac Tio hemo-ilmenite (Table 2.11.
These results (Table 2.1) were obtained from the chemical analysis of
48 hemo-ilmenite concentrates which have been prepared from samples that
lie within cross-sections ?K ana LM (Fig. 3.1 and 3.2) of the ore deposit.
(a)
(b) white : hem, gray : ilm. dark : hem. light : ilm.
(c) (d) w4lïte hem. gray ilm. white hem. gray . ilm.
Figure 2.3 Mic,ophotograOs of twinnétg _iiemo-ilmenite cr;vstPls. 2.3a) Disto.r4 ~on of hemat,ite, lamellae due to twinning. 2.3b) Twinn51-1,7 5.n one direction. On that samnlP ~he hematite
was etche :' in LoncPntrai:ed HC1 in the presence of copper.
2.3c) e=lidc. ..twinning and twinnirj in two directions. 2.3d) Twinning in three directions. The sezticn shown was
cut perpendicular ..o the c-axis of the crystal.
Table 2.1 NNW
Chemical Composition of Averape LaTio Hemo-Ilmenite
Wt.%
Mol. Prop.
TiO2 37.9 .4743
FeO 29.1 .4035 MgO 2.21 .0548 Mn0 0.16 .0022 .4623
CaO 0.10 .0018
Fe203 29.2 .18271
V205 0.40 .0026 A1203 0.23 .0022 Cr203 0.10 .0006J
Wt.% of ilmenite phase 70.03 Atomic formula of ilmenite phase (Fe o 87 frig, u8.004 Ca.004) U.
Ti02
Wt.% of hematite phase 29.97 Atomic formula of hematite phase (Fe.971V.014A.012 ÿr.003)203
Excess TiO2 : 0.96% (Wt).
.1881
These results indicate that the Lac Tio average hemo-ilmenite
contains 30 per cent by weight of the hematite, the remainder being
ilmenite. Whereas tie calculated formula of the hematite is practically
pure Fe203, the ilmenite contains appreciable MgO (11.8% Mol.) substi-
tuting for FeO. The average heLno- 1Jneaite, like most hemo-ilmenite from
lac Tïo,yielck on analysis a slight excess of TiO2. The excess TiO2
can probably be accounted for tj the small amounts of anatase and/or
rutile found in most samples. This LsTect is further discussed in
section 2.2.6.
2.2.1.3 Minor Element Distribution i n Unmixed Ilmenite and Hematite
Electron microprobe work was carried in order to determine
the distribution of Ti, FP, Cr, Mg, V anf Al(I) amongst the unmixed
ilmenite and hematite phases of Lac Tio ore. Using a crystal cut parallel .
to its c-axis, an electron probe traverse at right angle to the hematite
lamellae was first oùt€fined. The intensities recorded for Ti, Fe, Cr and
Zig are shown in Figure 2.4. A anantitative analysis was next obtained
for the above mentioned six elements in the respective unmixed phases.
The results obtained are summarized in Table 2.2.
Table 2.2
Electron Probe Analysis of Unmixed Ilmenite and iieratite A1~
Fe Ti Cr V Mg Al
Ilmenite gro....mass 36.5 32.7 N.D. 0.10 1.7 N.D.
Large hematite lamellae 53.3 8.1 0.10 0.50 N.D. 0.14
N.D.: Not detected
Although the data of Table 2.2 were obtained from spot analysis,
it should berointed out that, because very minute ilmenite lamellae
are nresent in the larger hematite lamellae and vice versa, it is not
possible to obtain intensities that are free from the contributions
of minute lnmellae. Dermite these' limitations, the data of Table 2.2
indicate that Mg is preferentially concentrated in the ilmenite phase;,
whereas Al, Cr and V are held in the hematite phase.
No attempt was -jade tn determine the composition of ti.;.
lamellae since the size of tee lamellae :gis too small for meara:f Igful
probe analysis.
(1) The microlvrobe work yes carried out at the Kenrecott Conner Laboratory in Lexington. ;Massachusetts. Iron, titanivaa, chromium, aluminum and magnesium intensities were collected uei.ng routine instrumental condi-tions. licwever, vanadium intensities were collected using a LiF crystal and slits permitting the resolution of the VKA neak • from the Ti's( peak.
200 300 MICRON
•
Mg
ILMENITE Ii.n"ENiTE
Fe
INT
EN
SI T
Y
Fig. 2.4 Qualitative electron probe traverse across an hemo-ilmenite grain. Detailed explanation is presented in the text.
-44 -
Similar work involving iron and titanium only was also carried
out at the Mines Department in Ottawa. Figure 2.5 shows the relative
distribution of these two elements in an hemo-ilmenite grain, The tra-
verse which covers 70 microns distinctly shows the presence of minute
ilmenite lamellae (A) in the hematite and vice versa, the presence of
minute hematite lamellae (B) in the ilmenite groundmass.
2.2.1.4 ,Lattice Parameters and. Composition of Unmixed Hematite and. AMMO 11. 11M,M=1,
Ilmenite
Powder patterns of hemo-ilmenite show the presence of both
the hematite and ilmenite diffraction snectra and therefore confirm
the microscoric examination. Since hematite and ilmenite are isostructural
compounds, they have snectra that are closely similar. Only a slight
displacement of corresponding; necks is observed as a result of the
small difference in the axial parameters of the wlo minerals.
Hematite and ilmenite form at high temperature an homogeneôus
solid solution series with ensuing continuous variation in lattice
parameters and other physical properties. Lindsle:r (1962) provided
a graph relating 20 (024) and 20 (116) of hematite-ilmenite solid
solutions to composition expressed in mole % of the end members (Fig.
2.6). This graph enables to determine the composition of hematite-
ilmenite soliô. s^utions by measuring 20 (FeK 1) of the (024) and
(116) reflections.
The (116) reflection of some 150 specimens of Lac Tio hemo-
ilmenite was carefully measured using a Guinier-De Wolff multiple powder
camera and a Nonius-Guinier viewer. Silicon was used as an internal.
10 20
. ~
r
0
'RE
LA
TIV
E
a~ ~
INT
EN
SIT
Y
B
HEMATITE
A
INIONMEMBERENAMIIMMEIMMEM 411MMN ~ III ~
r ►
30 40 50 60 MiCRON
r
ILMENITE
4 A,r. i1.1,,t~,^r'i
~ ~
Fig. 2.5 Electron probe trPverse across an hematite lamella, showing the relative distrtibution of Fe and Ti in the two main phases of the Lac Tïo hemo-ilm.enite•
fL1111j1111111 WHIT It11 ► 1 ► 1111►► I111111 ► III 11111 ► n1j11►► f:1► 1111 ► 1j ►. 1n1r11 ► 11 ► 1 ►► 1 ► 1~111j1 ► 1~~ 63.50
I r AVERAGE 2a OF LAC T10 HEMATITE PHASE. I
AVERAGE 28 OF LAC T10 ILMENITE PHASE-->>y 69.501= . ■ I
1 1 I C = 1 6300 i
I 1 1 ~D I
® N o
62.50
1 i
11_111111111111111111111111 111111 t 11111111111,t.L1111111111111111 i 11;y1,11
8
.111
ô
69.00
N 0
68.50
~
0
20 40 60
80 100 o - Fe203 M OL. PER CENT
FeT103
HnlATIT£
ILMENETE
Fig. 2.,6 Liw 37.e.r'a curvetrelating 20 (116) and 20 (021+) - Fe.Kva., with the composition of hema:.ite-ilmenite solid solutions (Lindsle7, 1962). The average 20 anglzs fcr the hematite and ilmenite phase from Lac Tio are indicated by dotted vertical lines. Points (C) and (D) are 20 angles for giekie].ite (M TiO3.ASTI4). Points (A) and (B) are calculated 20 positions for an ilmenite of composition (fr>;.12Fe.38)Ti0 , corres-ponding with the composition of the average. ilmenite phase from Lac Tin. (See te:ct for exv lanai i n.- ) .
-47-
standard. The average 29 FeKat obtained are summarized in Table 2.3;
refering to Figure 2.6sthe data would indicate that the average
hematite phase contains 14% mole or ilmenite in solid solution whereas
the ilmenite phase would contain osa average 8% hematite in solid solu-
tion. However, va discussed earlier, microprobe analysis indicates
that most of the magnesium is held in the ilmenite structure. The
substitution of Mgt + (ionic radius .65) for Fe/4 (ionic radius .76)
should reduce the cell dimensions of the ilmenite.
The atomic formula for the average ilmenite was discussed
in section 2.1.1.2. Neglecting Mn and Ca which occur only as traces
(Table 2.].)s the average ilmenite formula would be (Mg.12Fe.88) 0.Ti02.
Assuming linear re].ationshipc between lattice spacings and composition,
the 28 of the (116) reflection may be calculated using the pure end-
members diffraction data(1). Such calculations for (Mg.12Fe.88) 0.Ti02
yields : 20 (116)=68.390. When compared to the data of Table 2.3,
these results suggest that Mg,substituting for iron in the ilmcnite,
is almost alone responsible for the variation in the reflection (116)
of the unmixed ilmenite phase. The ilmenite phase would accordingly
contain little or no hematite in solid solution.
Table 2.3
(116) Reflections of Unmixed Hematite and Ilmenite
Unmixed Lac Tio hematite (Average) Unmixed Lac Tio i.1 s ni.te (Average) Pure hematite (synthetic) Pure ilmenite (synthetic)
28 (116 ) Fei;oll
69.54 68.43 69.68 68.29
11) Géikielite (77O.Ti02), sl(116) = 1.708A°(A.S.T.M.)
Ilmenite (FeO.Ti02),d(116) s- 1.7244 A°(Lindsley, 1962)
iminsizsgammEmEMEIEFWEIW211111111MEMORMINEMERIONEYAMEI'0►
The average hematite calculated from the average hemo-
ilmen:ite from Lac Tic (Table 2.1) contains only very minor amounts
of Al, Cr and V, the presence of which should not alter significantly
its lattice spacings. In spite of this, the (116) spacing of the unmixed
hematite is significantly larger than that of pure hematite (Table 2.3).
It thus-seems relatively certain, referring to Figure 2.6 that the
unmixed hematite in Lac Tio hemo-ilmenite holds in the order of 14 Mol.
% FeTiO3 in solid solution.
Table 2.4 lists the results of unit cell parameter determina-
tion;for unmixed ilmenites and hematites from Lac. Tio and for various
other ilmenites and hematites. The determinations were made wing the
diffractometer with silicon as an internal standard. Reflectiox.s (104)
and (110) were used for the calculations. The unmixed hematite i.. seen
to have axial parameters slightly larger than those of synthetic hema-
tite whereas the axial parameters of the unmixed ilmenite are slightly
smaller than those of synthetic ilmenite.
Table 2.4
Unit Cell Parameters of Unmixed Hematite and Ilmenite
Cell Paramete.~ta (hex.sys.)A°
s.o co
Cell Parameters (rh.sys.) A°
arh a4
Synthetic ilmenite (prepared at Q.I.T.)
5.085 14.075 5.534 54°42'
Norway ilmenite 5.084 14.062 5.530 54°44'
Synthetic hematite 5.035 13.755 5.42 55°16' (Fisher Reagent)
Isle of Elba hematite 5.038 13.756 5.405 55°33'
Lac Tio hematite phase
5.047 13.762 5.435 55°20'
Lac Tie ilmenite phase
5.081 14.041 5.523 .54°46'
Precision ±.001 .003 t.001 t 1'
.ainiJmlimm EAMIN .. ;L`•=427, ~!"~.
-1+9 -
During the microscopic examination of sections cut perpen-
dicular to the c axis of the crystals, several hematite "discs" or
blebs were noted to display trigonal cracks reflecting the symetr;r of
hematite. A good example of this feature is shown in Figure 2.7.
These cracks probably developed from tensional stresses resulting from
the fact that the hematite "guest" has smaller cell dimensions and
volume than the ilmenite host (Table 2.4e).
Fig. 2.7 Trigonal cracking in exsolved hematite phase. The hemo-ilmenite crystal was cut Perpendicular to its c-ax5.s. (X200).
2.2.1.5 Di tribution and Variation of Ilmenite and Hematite in the G e
The distribution and variation of the ilmenite and hematite
unmixed phases. in the orebody was investigated by measuring the (116)
reflection of the minerals in some 150 samples representing the entire
deposit. This work was done with a Guinier-De Wolff X-ray diffraction
camera and monochromatized CoKpt radiation. Although this work did not
reveal major variations in the orebody, a small difference in the compo-
sition of the ilmenite-hematite solid solutions has been observed in
samples from the low grade part cf the deposit. Figure 2.8 which
represents an east-vest cross section of the orebody shows the molecular
T79 T r ,rnT
-~. .e
) M
~,~ 1 i 1 1
/ •
ow v
. _~ .._----
Su! ~3.r 7. ~ T ' -ri
Sap
♦ ?•- ' I •
•\ •..-, :L;f
•• ~'~ ``J-,~
,.
-
• •
; \
i a
~-
'~
1~:
8.0,:
,=. ♦ ~ . . _,._,~.,, -•.- ,•]j
%
a•/ .:::.:
, I / ~-,v: •
‘ ~---- 725A;~ =
' • : ':~'', 13.0~ • g •
70%
~.cGEn.J
^ ! 7 I~w~V~~L~yi4T`
30-70 % la: •v.o -tLnaEhIY&
R.":anYMO.:ITZ
DIP SECTION
OF LAC TIO ILMENITE DEPOSIT
SCALE 1"=eco'
Figure 2.8 Molecular percent of ilmenitc dissolved in Lac Tio hematite phase.
L
• ' ,•, + , y'~~, zf~.,, i
1 : : . : . . • T ~R r:~, : : : : . • - ~• n A ♦ - ' 1 /l'a ;j.:;:.::'•:•... ~ ~:~i=~i ..7:•:•:::::•".. ÿ ~ ~ ;• : •
''...•• ± . _ .. s ~..T-~' `+` ^ _ ~ _
•..
• I •- a • ♦ . • \ l' •♦ • •, ,. ~ ~.. ~ ~~ ~. . .• ~ •.. { ~ ~ : - • ~ L_ T.':7.5 "r-e4 ‘, ♦ • ' ' \ # • / • ~
, 07,......::,, • ... ....
-. - • • - • #1 - ~ • • ♦ 7 .r..: ~-
► 7
~~;:ï::; : ♦ ♦ / • i I ,~ - ♦_ I • 1 7• _ 1 ♦~" i7.
/ - v 1 r• ♦• ~ n~\•.,~;•
24,
•• I • a
.. ,••:~: -a •` ♦
-.4
-s . -%O. :,~
?i ♦ • • e • -
.'t: ;'' 93.0 \• . •, '•' • : ♦ ' - ~~::~: c ~ : ~•~.~:•:: ' ;£' • :~ • . . ; tt
;• a .1- a .
~;.~~~>.~13ip?,;;•:r :,. ~• •~•-♦•,••• ~:..~ 13. ~:: : . . • : 1
.7:4•4.? _ - ' ~
~. S - ,.c:; '••~.~: :~ • ~~ ~• - • , t
.;•~ :^,••;::•:::• .••'.• 411; !,~ . ' ~ ~ :r•~~i 1.7~,5 `:•: r:~,'; .%: 'r ~: ;
.:-
.t...7
+ •.' v~ .;::::•;•:. r ' •. •'l',.,',-.
r_ • i
:\i~•.~1 ••+~ :~~•~ ;L..ti••':`.:~ • r ,+ ~v • .•
.~/~~- 1 .•cl~••.. \:
1:~• y.y . ~~;~•: •.~;:Yt ?5~~~?i. ; '?•, • ~• , `- ~ i ~~ ' :': ~" 1 F.A. ~ .•: : :•. . . • . • • '
3:.::<‘..)...Z.:114 ~~ .-~ =`'`''' 4.0:.:.::::t~ " Q~':
.•<':~, r . . c 5 ~:~..~;:_:~ ;-:.: ` .
`•!fi: •^:'+~''~`::~vT.~` '
~ • ~~~~i%1 ; -
• t+,
: :•t'l3 0 ~` ~~ "~ :•: ; ....:•.,:: Ji • • ti,~ • • ' ~ 1 ~ :~~: ~::~: 1, •'. , • . :•:•:...:.';' • . / • - - 12.0` • ~
?. ..`.....::•••••:•0: `; ~ 11 1
~ _i
~ •- ..‘,.....1...... ~ ~ ::: r•;: ~~ / • ~ I - a ~L•::;;,•: •: .~ ~:•• . •::044.0-4...4%.:
♦ ♦ ♦
....•••••••••••
= • 'e••',.'
.z........4.
::i+~
.# 2...44
~:"•'i - ♦ •- i •~ ~ ♦
,- 1-• ; / ` ,~;
: a • 1 1 • , -
°
- /
0 , , - / ~ • 0'1 , • ~ I.
~
tr. -. a, • - a - 1 1, . I I t
I • •
I•• . ~~• •~
A;• • - • •,•
qt
~ O 0
-51 -
amount of ilmenite dissolved in the hematite lamellae. From Figure 2.8,
one notes that in the low grade part of the deposit (east+.rn limit),the
hematite phase of the hemo-ilmenite contains slightly higher amounts
of dissolved ilmenite than elsewhere in the deposit.
2.2.2 Plagioclase
Plagioclase constitutes the larger part of the waste discarded
at the beneficiation plant. The mineral is generally coarse-grained and
has a specific gravity of 2.7. The feldspar is derived from the anor-
thosite rocks that enclose the orebody and also form layers or isolated
blocks within the hemo-ilmenite mass. In some parts of the orebody
the plagioclase is also found disseminated within the hemo-ilmenite ore.
However, this type of disseminated material generally occurs as large
zones which can usually be avoided dvxing the mining operations. The
disseminated plagioclase-hemo-ilmenite rock probably constitutes less
than 10% of the volume of the deposit.
From determinations made using the Rittmann zone method (Emmons,
1943) and from refractive index of fused plagioclase glasses (Foster,
1954), the plagioclase found in the deposit is usually a caleic
anIesine (An46Ab54).
Chemical analyses of anorthosites surrounding thee orebody
are presented in Table 2.5. Sample no. 1 is located in the anorthosite
overlying the deposit, sample no. 3 is from anorthosite that underlies
the deposit, whereas sample no. 2 is from the country rock adjoining
the deposit to the east. The three samples are closely similar chemi-
cally and mineralogically. Under the microscope the rock is seen to
-52-
AO.
Table 2.5
Chemical Composition of Anorthosite from Lac Tio(1)
. Sample No. 1 Sample No. 2 Sample IJo. 3 J.D.H.87-13;6.5ft D.D.H.87-13;635 ft. D.D.H.87-1;1193 ft
Si02 54•8 55.6 55.4 A1203 27.55 26.05 27.12 CaO 10.1 9.5 9•4 Na20 5.68 5.57 6.51 K20 o.68 0.96 0.80
Fe0 0.37 0.41 0.30 Fe203 0.43 0.76 0.34 TiO2 0.20 0.15 0.15 MgO 0.24 ., 0.31 0.17 MnO 0.007 0.011 0.007
/ Cale. ap
r1t.~o.Comp. An4~Ab47,30r3.7 An47Ab470r5'7 An43.6Ab51.80r4.6
Comp. Tsuboi's An47 An47 An44 Method
_.._.~.....~
(1) Analysed at "Laboratoire de Géochimie Analytique, Ecole Polytechnique".
~ ~..... ~
~
a~.
- 53 -
consist principally of coarse subhedral plagioclase crystals and small
amounts(less than 3%) of mafic minerals, mainly interstitial augite
and lesser opaque minerals, rimmed with biotite.
The plagioclase of all three samples is antine='th;itic and
contains needle•like inclusions of rutile (Figure 2.16) and minute
hematite platelets. The orthocla:;.e is distributed as minute blebs and
lamellae in the plagioclase crystals. Commonly the orthoclase blebs
are aligned along clivage or twin planes. The plagioclase in all three
samples is calcic andesine (An44-47) as determined by refractive index
using Tsuboi's method (Morse, 1968). These determinations agree well
with the compositions calculated from the data of Table 2.5, when all
CaO, Na20 and K20 are assumed to represent the plagioclase.
On the basis of composition, mineralogy, petrography, structure,
environment of occurrence and in some cases, age, Anderson and Morin
(19691 have recognized two types of anorthosite massifs; the labradorite-
ty a massifs are irregular in shape and are composed predominently of
gabbroic anorthosite. These massifs contain magnetite, ilmenite and
plagioclase of composition An63-45
Or2_3. Contrasting with the lsbra-
dorite-type massifs, the andesine-type massifs are domical and are
composed mainly of anorthositic rocks. Minerals such as hemo-ilmenite
and antiaerthitic andesine 4th a composition of An48_23 Or6_25 are
also characteristic of the andesine-type massifs. On the basis of these
criteria, the Allard Lake anorthusite massif can be classified as an
andesine-type anorthosite massif.
- 5'+ -
2.23 Sulphides~
2.2.3.1 General Distribution
Pyrite is by far the principal sulphide minral in Lac Tio
hemo-ilmenite oie. ; ;owever, chalcopyrite and traces of pyrrhotite,
millerite and Co-Ni sulphides of the linnaeite series have also been
!.dentified in the present investigation. The sulphide minerals generally
constitute approximately 0.5% of the ore and occur as one to two milli-
meter anhedral crystals interstitial to the hemo-ilmenite grains.
Figure 2.9 shows the typical association of chalcopyrite with pyrite
in Lac Tio ore.
The distribution of sulphides in the orebody was investigated
by analyzing the sulphur content of the ore. For this, a series of 55
samples each representing 10 feet of core were selected in two sections
of the upper portion of the orebody and analyzed using the Leco analyzer.
The sulphur content was found to range from 0.03 to 0.95 with a mean
value of 0.28 percent. This work showed that there is no apparent trend
or pattern in the distribution of sulphur in the two sections investi-
gated; also, no correlation could be established between the grade and
the sulphur content of the ore. For example, values of 0.05% and 0.95%
sulphur have been obtained for samples which have a grade of 94.0% and
93.4+% respectively. The investigation also showed that wide variations
in the sulphur content are found in the same drill hc1e. For example,
in hole 87-5 (Figure 1..12) where eight core lengths representing 80
feet of continuous ore have been analyzed, values of 0.95, 0.11, 0.12,
0.06, 0.05, 0.28, 0.25 and 0.08% sulphur were obtained. Variations from
-55-.
Fig. 2.9 Pyrite (P) and chalcopyrite (Cp) in Lac Tio ore (X120).
-56 -
hole to hole were also found in this study. For example in hole 87-6
(Figure 1.11) none of the samples in the 70 feet analyzed contained
less than 0.36% sulphur, while in hole 37-5 (Figure 1.22) only one
sample contained more than 0.28% sulphur in 80 feet of ore. In hole
87-5, the average sulphur content was 0.20% while in hole 87-6 the
average was 0.50%. The results obtained in this investigation seem to
indicate that the sulphides are unevenly distributed throughout the
Lac 'iio orebody.
2.2.3.2 Chemistry of the Vulphides
A preliminary study by Dr. A.N. Mariano(1) has shown that the
sulphides associated with the Lac Tio ore contain some copper, nickel
and cobalt. In his study, Mariano et al (1970) determined the cell edge of
pyrite to be 5.4191A°.This value is slightly large than the cell edge
of pure pyrite (5.14171A°)and may, according to Mariano indicate that
some nickel and cobalt are in solid solution in the pyrite structure.
Pursuing this work, the author has studied the distribution of Cu, Ni
and Co amongst the principal mineral phases present in the ore. For
this, concentrates of hemo-ilmenie, magnetite, spinel and sulphides
were prepared and analyzed for Ni, Co and Cu at the Kennecott Labora-
tories. The results of this work are presented in Table 2.6.
nIMIKIMININIMPr 11101•=1,
(1) Kennecott Laboratory, Lexington, MLss.
Table 2.6
^istr. ibution of Cu, Ni .and Co in the al
of the Lac Tio Ore ~~..
% Co Dist. j Cu Dist.. % Ni Diq;
Hemo-Ilmenite 0.009 59% 0.003 50% 0.022 85%
Spinel 0.084 5 N.D. 1 0.078 3
Magnetite 0.015 1 0.061 10 0.107 3
Sulphides 1.1 35 0.5 40 -242-----2
Total in Ore 0.0155 100 0.006 100 0.026 100
The results of Table 2.6 indicate that for an average ore
containing 0.25% sulphur (equivalent to 0.5% pyrite), 35% of the cobalt,
40% of the copner and 10% of the nickel are found with the sulphides;
the remaining amounts are located mainly as solid solution in the hemo-
ilmenite and cannot be eliminated or recovered by physical means.
2.2.4 Sninel
Spinel is present in amou:its vzhying from one to three percent
in the ore. In this study, a sample of spinel vas concentrated by
leaching a typical hemo-ilmenite sample with hydrofluoric acid. The
spinel was found to ::onstitute 1.1 percent of that particular sample
of ore.
The mineral occurs in Lac Tio ore in three different forme.
By far the most common spinel occurs as one to five millimeters anhedral
grans interstitial to the hemo-ilmenite crystals. However, although
interstitial spinal is the most common relationship observed, some
spinel appears as if included by hemo-ilmenite. It is not sure yet,
..58_
whether the "included" spinel are really included in the hemo-ilmenite
or if they are projection from interstitial aggregates from above or
below the section. This spinel is pitch black in hand specimen and bottle
green in thin section (Figures 2.10, 2.11, 2.20),has a specific gravity
of 3.8 and a retractive index of 1.77. Cell edge determination of the
spnel using a 114.6 mm. camera yielded an axial parameter of 8.1197±
.00051 . This value agrees remarkably well with a previous determination
on anothe: sample, which gave 8.1188 ± .0005A° (1). A partial chemical
analysis of a spinel concentrate is given in Table 2.7.
Table 2.7 ,..----
Partial Chemical Analysis of Sninel from Lac T o -Qrs.
w 4 . t
Mg0 19.33
FeO 13.23 Calculated formula
Fe203 4.12 (M.172Fe.28)(A1.96Fe.04)20
1 Al203 65.08
'I Analyst : Laboratoire de géochimie analytique, Ecole Polytechnique.
The chemistry and physical properties of the mineral indicate it is
pleonaste, a spinel commonly associated with titaniferous ores (Deer,
Howie, Zussman, 1964).
Another variety of spinel is also found in the Lac Tio ore
:here it occurs replacing the hematite lamellae in the hemo-ilmenite
(Figure 2.12a). However, the concentration of this type of spinel is
much lower than that of pleonaste. Figure 2,12b to 2.12d are electron
probe "X-ray pictures" corresponding to Figure 2.12a; the high alumina,
low iron and absence of titanium identify the spinel on the photographs.
(1) Value determined by A.N. Mariano.
- 59 -
Fig. 2.10 Photomicrograph showing the most common spine]. adjoining hemo-ilmenite hematite, (i)?menite,
pleonaste spinel, in the ore, : (h) etched (s) spinel (X400)
Fig. 2.11 Grain of green pleonaste as seen in transmitted light (X120).
- 60 •-
(a) (b) Al
(c)mTi
(d) - FF
Fig. 2.12 Replacement of hematite by spinel.
(a) Fhotomicrorranh showing spinel invading ilmenite along hematite lamellae. (X400)
(b,c,d) Are electron probe "X-ray pictures" showing the distribution of Al, Ti any. Fe in region (X240).
(a).
-61-
A third and much rarer variety of spinel is also found in
the ore. It usually occurs close to the boundary of hemo-ilmenite
crystals. Characteristically, the ilmenite adjoining this spinel has a
border zone devoid of hematite lamellae and often contains rutile
(Fig. 2.13 and 2.l1). Electron probe traverses across a spinel grain
and the. bordering ilmenite rim has shown that Fe, Mg and Al decrease
regularly from the center to the edge of the grain. From the edge of
the spinel grain outward across the ilmenite border zone, the relative
amount of iron increases while that of titanium decreases. No signifi-
cant variation could be recorded for Al and Mg in the border zone of
the hemo-ilmenite crystal.
Mariano (1970) has reported the presence of gallium in the
spinel of Lac Tio ore. Persuing Mariano's work, a concentrate of
spinel was prepared and analysed for gallium. The results showed
that 0.1% gallium is contained in the spinel where it typically substi-
tutes for Al. This amount represents one third of the total gallium
content of the ore. Although gallium occurs in trace amount in the
plagioclase, the remaining two third mainly occur as a solid solution
within the hemo-ilmenite.
2.2.5 Magnetite
Magnetite generally constitutes less than one percent of
the ore. In a group of 48 samples taken from sections JK and LM (Fig.
3.1 and 3.2) of the orebody, only two samples contained as much as
3 percent magnetite. The mineral occurs in three different forms in
the Lac Tio orebody. The most common magnetite is found replacing the
~ ~,~, :~•~~~ ~`
-.62-
• ` ~•..~~ t ,
~,, . ~..'~ .,. ..~
~s° \ •~' ,~~:\` \ ~~i.•,. •`~ . . . ' ~~,~.` ~ . ; ~~ `ç ~
• • .
ti `~. .'\``e `~•, ,.f~µ •
•
Fig. 2.13 Spinel (s) of the third variety adjoining an hemo-ilmenite crystal. Note the hematite free rim adjacent to the sDinel (X400) .
Fig. 2.14 Spinel (s) adjoining hemo-ilmenite. The presence of rutile (r) in the hematite free rim may be seen (X450).
-63-
exsolved hematite lamella (Fig. 2.15a). This type of magnetite occurs
principally along cracks in the hemo-ilmenite crystal and seems to
be responsible for the variation in magnetite content observed in
the orebody. In many instances this type of magnetite has been found
associated withhsecondary anatase (Fig. 2.15b). Indeed, microscopic
observations of selected ore samples commonly show the alteration of
ilmenite to anatase together with the magnetite which has replaced
the hematite lamellae.
A second type of anhedral magnetite is present in small
amounts in most ore specimens where it is found associated with the
sulphides. A typical example of this magnetite which probably repre-
sents less than 0.5 percent of the ore is shown in Fig. 2.15c. The
lack of alteration products and the well defined grain boundaries
seem to indicate that this type of magnetite is primary. Attempts to
concentrate this magnetite for chemical analysis were not successful.
However, it was possible to analyse (1) some magnetite grains using
the electron microprobe. The results showed that the primary magnetite
is almost pure. Indeed, except for titanium which is present in the
amount of 0.20 percent, no other elements could be detected with the
microprobe. On the basis of these results, a content of approximately
1 percent ulvospinel in solid solution, has been calculated for the
Lac Tio primary magnetite.
A thin, type of magnetite is occasionally found along the
main faults of the orebody. This type of magnetite is not very abundant;
(1) The analysis was carried out at the Kennecott Laborator.es,
Ledgemont, Mass.
-64-
(a)
(b)
(c)
Fig. 2.15 Photomicrographs illustrating textti.,xal relationships of magnetite.
a) Typical microphotograph showing magnetite (m) replacing hematite (h) lamellae in hemo-ilmenite (X200).
b) Secondary magnetite (m) replacing hematite (h) (X400). Note the association of anatase (a).
c) Primary magnetite (m) adjacent to a pyrite (p) grain (X400).
-65 -
it occurs in zones a few inches thick and is usually associated
with chlorite and rutile. This type of magnetite was not studied
further for it is clearly post ore in origin and probably results
from special physico-chemical conditions developed during the faulting.
The oxygen fugacity and temperature of formation deduced from this
magnetite would not represent conditions prevailing during the
formation of the deposit.
To summarize, the Lac Tio hemo-ilmenite ore contains very
little primary magnetite. As explained in section 2.2.5, the varia-
tions in the magnetite content. of the ore is probably largely due to
the varying concentration of the secondary magnetite that replaces
the hematite lamellae. Due to Lh,, rarity of primary magnetite
in the orebody, it is almow, i::possible to determine satisfactorily
the conditions of temperature and oxygen fugacity prevailing during
the formation of the deposit.
2.2.6 Rutile and ;natase
Rutile is found only in very small quantities in the Lac
Tio orebody. One of the main occurrence of the mineral is near the
main faults where it is sometimes present together with magnetite in
widths of a few inches. Rutile needles are also commonly observed
in plagioclase (Fig. 2.16 and 2.17a) of the anorthoeite where it pro-
bably accounts for part of the small quantities (0.20 of TiO2 in
the analysis of anorthosite (Table 2.5). In polished sections of ore,
rutile may be seen to invade the hemo-ilmenite crystal, in the border
zone of spinel grains (Fig. 2.14). The rutile distribution is well
shown by the Ti electron probe scan (Fig. 2.17x).
-66 -
Fig. 2.16 Inclusions of rutile in plagioclase. Polarized light. (X200).
- 67 -
(a)
(b) - Al
(c) -Ti
(d) - Fe
Fig. 2.17 Distribution of rutile in hemo-ilmenite
a) Rutile (r) invading ilmenite (i) near a spine' (s) grain (X400).
b) Distribution of spinel in region (a) as indicated by electron probe "X-ray picture" of Al.. (X400).
c) Distribution of rutile in ilmenite as indicated by electron probe "X-ray picture" of Ti. (X400)
d) Distribution of Fe in region (a) as indicated by electron probe "X-ray picture". (X1600).
- 68 -
Similar to rutile, anatase is present only in trace amounts
in the orebody. In a group of 133 ore samples studied by diffraction,
only three samples contained enough anatase to be detected. Microscopic
examination of these three specimens has shown that anatase is a product
of alteration of ilmenite and forms preferentially along cracks and
twin planes. Figures 2.18a and 2.13b show the typical association of
anatase in the ore. The mineral is often found with secondary magnetite
and is always surrounded by a rim rich in iron. The phase that forms
the rim has not been identified; however, electron microprobe analysis
shows distinctly that the iron concentration is higher in that region
(Fig. 2.19a to d) than elsewhere in the crystal. In Figure 2.18b it
is interesting to note that the small hematite lamellae inside the
anatase grains have remained untouched during the alteration of
ilmenite.
In the course .af thi.a study no important local concentration
of rutile or anatase have been found in the orebody. The quantities
present in the ore are too small to influence appreciably the TiO2
content.
2.2.7 Chlorite and Biotic
Chlorite is not distributed evenly in the orebody and it is
difficult to evaluate its concentration. The mineral is mainly found
near the faults and in the heavily fractured areas of the deposit.
Although magnetite is commonly associated with chlorite in fault
zones, the. relationship between the concentration of chlorite and
magnetite has not been studied in detail. However, examination of the
geological log of the drill holes, seems to indicate that the amount
of magnetite is. highest in the vicinity•of chlorite. Small.amounts of
-69-
(a)
Fig. 2.18 Distribution of anatase in hemo-ilmenite.
a) Microphotograph showing the alteration of ilmenite (i) to anatase (a) along cracks (X200).
b) Microphotograph showing the alteration of ilmenite (i) to anatase (a) along twin planes. Note the unaltered hematite lamellae within the anatase and the iron rich rim bordering the grain (X400).
- 69 -
(a)
(b)
Fig. 2.18 Distribution of anatase in hemo-ilmenite.
a) Microphotograph showing the alteration of. ilmenite (i) to anatase (a) along cracks (X200) .
h) Microphotograph showing the alteration of ilmenite (i) to anatase (a) along twin planes. Note the unaltered hematite lamellae within the anatase and the iron rich rim bordering the grain (X400).
- 70 -
(a)
(b)
(e) - Ti
(d) - Fe
Fig. 2.19 Alteration of ilmenite to anatase.
a) Microphotograph showing the alteration of ilmenite (i) to anatase (a) in an hemo-ilmenite crystal (X200).
b) Absorbed electron image of region (a) (X400).
c) Distribution of anatase in region (a) as shown by Ti electron probe "X-ray picture" (X450).
d) Unalte;^ed hematite within anatase and the iron ri.:h rim bordering the grain (X400).
71
chlorite also occur as a reaction product separating hemo-ilmenice
and plagioclase or as an alteration product of biotite (Fig. 2.20).
Minor amounts of biotite are found in the Lac Tio deposit.
Unlike the concentration of spinel, which decreases proportionally
with decreasing`ore•grade, the biotite content probably increases as
the grade of the ore diminishes. However, even in low grade material
(80%), the mineral does not constitutes more than one percent of the
ore. The mineral is brown in thin section and commonly occurs as
rim separating hemo-ilmenite and plagioclase (Fig. 2.21 and 2.211).
2.2.8 Apatite, Corundum and Zircon
Apatite, corundum and zircon have been found in small quanti-
ties by the author. The minerals were identified in a concentrate of
sulphides prepared from high grade hemo-ilmenite ore. These minerals
are rare and constitute only a very small proportion of the ore. For
this reason, they were not studied further as they are not susceptible
to alter significantly the composition of the smelter feed.
Figure 2.22 shows a corundum crystal included within an hemo-
ilmenite grain (1). A similar occurrence of Lpatite crystal was also
observed in one of the several polished sections examined by the
author. The particular crystal was identified using the electron
microprobe.
(1) Microphotograph taken by A.N. Mariano, Kennecott Copper Laboratory,
Ledgemont, Mass.
-72 -
Fig. 2.20 Microphotograph showing chlorite (c) separating hemo-ilmenite and plagioclase (pi. One also notes the presence of spine! (s) and the replacement of biotite (b) by chlorite (c) (X35).
Fig. 2.21 M.crophotograph showing(brown)biotite in anorthosite. Note the rim of biotite bordering the hemo-ilmenite (X35).
Fig. 2`.22 Euhedral corundum (brown) included in an laemarilmenite crystal (X600).
2.2.9 Hynersthene and Calcite
Although hypersthene is a common ccsnstituenu of the anorthosite
country rock, the mineral occurs in only very small quantities in the
ore. The amount of magnesium contributed to the ore by this mineral is
negligible for the mineral generally constitutes less than half a ner--
cent of the ore. Figure 2.23a and b show hypersthene grains associated
with plagioclase in anorthosite. The conaosition of the hynersthene
mineral determined by Hargraves (1962) is given in section 1.5.2.2•
Calcite constitutes only an infinitesimal portion of the
ore. The mineral is observed in rare specimens as inclusions in
plagioclase (Fig. 2.24).
2.3 i•IineralorTical Summary
The iron and titanium ore at Lac Tio is made up almost entirely
of hemo-ilmenite of average composition Fe203 (30f) FeO.T102 (700
The original high temnereture solid solution of hematite and ilnenite
has unmixed to a regular lamellar intergrowth of hematite and ilmenite.
Chemical analyses together with microprobe analyses and crystal chemical
considerations indicate that the unmixed Phases have an average comno-
sition as follows :
hematite : (re .071V 014Al.01?_Cr.004)203
ilmenite : (;4r,118t1n.004Fe.873Ca.004)O.TiO2
Pssocigted with the hr•:mo-ilmenite are small amounts of Pri-
mary minerals, the principal one being,.nlagioclase An46Ab54, commonly
•antinerthitic, pleonaste spinel and. pyrite. Others such as magnetite,
zircon, hiotite, corundum, auatite, chalcorvrite, millerite, nyrrhotite,
Co-Ni sulphide of the linleite series and hypersthene have also been
-76-
(b)
Fig. 2.23 Microphotographs of hypershenP in plegioclase
a) Hypersthene grain in nlag:.oclase. Note the biotite inclusions in the crystal. Polarized light (X32).
b) Hypersthene (brown yellow) surrounded by plagio-clase ;.z-ystals. Polarized light (X35).
.- 77 -
Fig. 2.24 Microphotograph showing calcite i;clrsions in a plagioclase grain. Note the biotite rim separating plagioclase and hemo-ilmenite (black) (X100).
- 78 -
found in Lac Tio ore but all of these are present in only very small
amounts.
In our mineralogical investigation, a number of secondary
gangue minerals have also been observed with the hemo-ilmenite of
Lac Tio. These minerals are, chlorite, magnetite, rutile and anatase.
Chlorite, magnetite and rutile are commonly found together along
faults and in heavily fr3etured zones of the orebudy. Similarly,
anatase and magnetite commonly occur together. Indeed, whenever a
major concentration of anatase is observed in the hemo-ilmenite,
secondary magnetite can be found.
This study has shown that, in general, the Lac Tio hemo-
ilmenite deposit may be considered as mineralogically homogeneous.
A few exceptions to this are given below :
1•. The sulphide minerals seem to be unevenly distributed in the
orebody. However, the present work could not establish any trend
or pattern of. distribution for sulphides in the depoLit.
2. The amount of ilmenite in solid solution in the hematite phase
of the Lac Tio hemo-ilmenite is slightly higher in the low grade
part of the orebody than in the higher grade portions.
3. No important concentrations of rutile or magnetite can be found
in the Lac Tio deposit.
4. In rare cases, the ilmenite phase in Lac Tio ore is altered to
anatase. This transformation which occurs preferentially along
cracks in hemo-ilmenite is•often accompanied by secondary magne-
tite. Similar to rutile, no major concentration of anatase exists
in the deposit.
s
-79 -
These observrtions would suggest that, except for grade
itself, there are no mineralogical factors susceptible to alter the
future mining operations. In the light of present data, nothing could
be gained by selectively mining the Lac Tio deposit.
Our study of the crystal chemistry of the various minerals
of Lac Tio ore gave the following results :
1. Most of the magnesium in the ore is found it the ilmenite
phase of the hemo-ilmenite minerai.. As expected, the magnesium
ions (M i) replace preferentially the ferrous ions (Fe:") in
the crystals.
2. The sulphides in the average Lac Tio ore contain 35% of the
cobalt, 4O% cf the copper and 10% of the nickel. The remaining
cmounts are mainly found in solid solution in the hemo-ilmenite.
3. Pleonaste spinel contains one third of the total gallium
content of the ore. Again, the remaining amounts are in
solid solution in the hemo--ilmenite.
The above results show that most of the magnesium and a large
part of the Cu, Co, Ni and Ga are present as solid solutions in the
hemo-ilmenite of Lac Tio and therefore cannot be recovered by physical
means. These crystal-chemical considerations and the low concentrations
involved suggest that at present time, no minor elements are worth
recovering from the Lac Tio deposit.
CHAPTER III
GEOCHEMISTRY OF HEMO-ILMENITE FROM THE LAC TIO DEPOSIT
3.1 Introduction.
The purpose of this chapter is to describe the chemistry
and the chemical variations of hemo-ilmenites in the Lac Tio deposit.
For this, concentrates of hemo-ilmenite of high mineralogical purity
were prepared and analysed chemically for Fe, FeO, Ti02, MgO, V205,
Cr203, A1203, MnO, Ca0 and Si02. Because great care was taken to
prepare concentrates containing on average more than 99% hemo-ilmenite,
the data reported in this chapter provide a detailed and fairly complete
view of the chemical variationP to be expected throughout the
orebody.
3,2 Selection and Preparation of Material for Study
In order to insure adequate representation of the orebody,
the'samples were obtained from diamond drill holes contained in two
sections that are approximately perpendicular to each other. Section
JK (Fig. 1.11 and 3.2) intersects the oval shaped orebody along its
length and is referred to as a strike section; section LM (Fig. 1.12
and 3.1 is referred to as a dip section.
A suite of 48 samples, 22 from section JK and 26 from section
LM, were selected for study. The samples were selected irrespective
of grade and attempts were made to choose samples which represented
ten feet of core. Figures 3.1 and 3.2 illustrate the specimen locations
in sections JK and LM respectively.
80
T.77 •. T7) 7 Aresa
•t Surfaee ~
T8â•9 • ,, .
8 ~.~• ; ~ •••`.•. ••= • : ~ • • . . ... ••
3~.
1164 . ~L•••~ • ~ •i •° : ~: :•: :; v . • : . • • • • , . • . , ~ ~ • .~ ~ , ~
911'17
1l II` ~ 117r~?,: ~ •~.= ~s _ `• • = • '` • ~ ~• • 2oi9 + • • •~ wt2^~?` ••`
IOD6 :_1:~r.'~ .~;::?•, ~~rr•~ .~•;•~` • ~'~. .:::.'~;. .. ~~'r • j~^\ =
. •~'<':,.: r ~• _,;• . ;
1 r~ •
~tt6~~`?•:'>;,• 0 •' 7wie~;•:i.l,._. ~~!' .•z~ ,', •
e+:r~~? ;•~/• r • '1•,
••, ,` •/, • r; .. \ •
\ . . .;:; :;: 1 / 1 . ~
~Dh~
~~ . ~ •. • • • ~ '• :;: : ::~ •• • . • • ~ •
1 - ~ •Ÿ V - •:•:: •: : :'. '^ , I • • ' .
am,
w
•
'1'.. rr'
st siiisSc.ri~~ ^.
, /° ~ •~:: ::% ;~`:a~:(~:•::~Ÿ; i ~ ~~~~.. % • •• • •. - i •• ~.
' • 1 1 •. ~ ° • • • ,.:::• . ``' './` c.:: /•``~''' ./~ • -, -:
.. : .,, •.i' ~. ~^ '~ i
I . , t • ~ ~ ~ ~%~? ~ •" :. _ ., /. ° ,? ,_1::~ 7aS ::
I
e •.
y
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:- ,. •. ': ~:
~ • -~'â
91.j`, ♦• ~ i. • . • :
or ~ %~ l ;•• t.% i~ ~ .
~~:~~ ÿ ‘ ~..~ 7~5 1 : .. :.; ~ . ... ( • •~ .v:v. :
• ~ • -~ , ..%:•:••••• ~
• s..., 1 . . - • ;ï•~: ..~ ~ . ; •~~„_•. • . ~ • ~ • s
.v•~,. .. ~ ~ ;~~•% ,.0
I f • / •
0 f `
C•0 ~L.
7-,37.5%"' -c:
\~ \ ~~~.:ti~•iV✓••~ , ` • ~ ~ .• t t . I, ♦ ~ • • , ~ \ • ••' , i / ~ ~. 1 , 1 t ‘ . ,•„ • • .. 1
I ' • ° ,~ ~ ••~„ ! • % •. , . ~ • ~ . I- • t •:.•%•% 1„. I ~ , ••
t I • •
..r
dalr
~ 500
~ M
° -- -- A
LEGEND
~ 70% /4.1M3-ILP.;~r1tTE
30.70% ki•10-EI.AtENiTfi
APJoRTK6ZlY~
DIP SECTION OF
LAC TIO ILIVIENITE DEPOSIT SCALE :"_Lno°
~
•\\i
Fig. 3.1 Dip section: o`' Lac Tio orebody. The numbers are those of the diamond drill core samples.
7-64-!
67
T-67-2 T-78.
Sio
• ,..O? .71"93'"; ^ --
? 7 0 —8..—~ +~ ~, - - - ~ •~ .r
.... e5.en :.r~. 6 9C:"~.:•:'• ~.. , r Svtr.,.r T-87--~
2a7 -% .c`v - _.:.•::::::::: .::. • 3a ~"• .... .... ... . .........:.~:•.~.:.~..;~^ ..~~.::r'•:''{~:•'}253 ....- . .. _
O
K
LEGE:~D
> 70% HEMO-1LMEAlITE
30 :TO % c15it70.• 11.MEw1TE
ANqRYKGtTE
LAKES
STRIKE SECTION
LAC Y10 iLMEN6TE DEPOSIT
Sghtz i"a âCo'
• ,.
Fig. 3.2 Strike section of Lac Tio orebody. The numbers are those of the diamond drill core samples.
-83-
The hemo-ilmenite ore samples were then subjected to
careful mineral separation treatments in order to obtain concentrates
of hemo-ilmenite. The details of the mineral separation procedures
are given in Appendix I. The average concentrate obtained after these
procedures consisted of a black -150 +200 mesh powder containing more
than 99.hemo-ilmenite, the principal impurities being odd grains of
spinel, F;.Tite, plagioclase and pyroxene.
3.3 Analytical Methods and Preparation of an Hemo-Ilmenite Standard
All of the chemical analyses required for this study were
done at the Q.I.T. Research Center at Tracy, Quebec. The major consti-
tuents, Fe, FeO, TiO2 and Si02 were analyzed using wet methods whereas
14gO, V205, Cr203, CaO, Mn0 and A1203 were analyzed by atomic absorption.
The analytical procedures were controlled by using a specially prepared
hemo-ilmenite standard. A concentrate (approx. 5 lbs) of high purity,
hemo-ilmenite was prepared and samples of this standard were inter-
calated at random with the samples to be ana2.yszed. The preparation of
the hemo-ilmenite standard is described in Appendix II together with the
results of twelve replicate analyses of the standard. The mean compo-
sition of the hemo-ilmenite standard, the standard deviation and the
analytical variation attached to the various determinations are given
in Table 3.1.
84
Table 3.1 441111.
Ma.ior Element Composition of Hemo-ilmenite Standard
Element Standard Deviation Analytical Variation(3)
Fe 43.1 0.2 0.48% FeG 28.2 0.2 0.71% Fe203* 30.3 0.3 1.0% TiO2 37.6 0.2 0.53% MgO 2.42 0.03 1.2% V205 0.42 0.03 7.1% Cr203 43101° o, (S 0.01 10.0% A1203 Si02
44 P- ®; 35. 0.15
0.01 0.04
. 5.0% 26.6%
CaO o.o / o.J1 10.8% Mn0 0.16 0.01 6.3%
Total 99
* Calculated
Wt.% of hematite phase : 31.04%
Atomic formula of hematite (Fe.97A10.013V0.014 0.003203
Wt.% of ilmenite phase : 68.63%
Atomic formula of ilmenite (Fe.86Mgwi3Mn0.005Ca0 003)0.TiC2
Excess TiO2 : 1.92%
The minor elements in the standard hemo-ilmerite are presented
in Table 3.2. Of these, P205 was determined by the wet method,sulphur
with the Leco analyzer, potassium, sodium, cobalt, nickel and copper
were analyzed by atomic absorption methods and gallium was analyzed by
X-ray spectrometry using Ge02 as internal standard and Ga203 as a spike.
1) Also known as the coefficient of variation.
-85-
Table 3.2
Minor Element Composition of Hemo-Ilmenite Standard
Element .~.... Analytical Error
S 0.01 ± 0.002 K 0.004 ± 0.002 Na 0.011 ± 0.002 Co 0.009 ± 0-0011: Ni 0.022 ± 0.002 Cu 0.003 ± 0.002 Ga203 0.002 t 0.001 P205 0.009 t C.003
Total 0.070%
From microprobe results discussed in Chapter II and from
tl'e results of careful microscopic examination of the standard hemo-
ilmenite concentrate, it would appear that the crystal chemist ^f
the hemo-ilmenite involves principally Fe, Ti, Mg, V, Cr, Mn, Al, Co,
Ni, Cu and Ga; the minor amounts of Si, S, K, Na, Ca and P reported
in the analysis are most likely due to rare mineralogical impurities
such as pyroxene, plagioclase, pyrite and apatite.
3.4 Chemistry of Homo-Ilmenite in the Deposit
The results of the chemical analyses of 48 hemo-ilmenite
concentrates obtained from sections JK and LM are contained in Appendix
I. These data are summarized in Table 3.3 where the range, the mean
and the coefficient of variation of each constituent are given together
with the gracie, the Fe/Ti02 and the Fe203/Fe0 ratios.
- 86 _
Table 3.3
... Chemistry of Lac Tio Hemo-il.menite (1)
Oxides Hirsh Low Mean S.D. Coeff. of Var.(2) Anal.Var.
TiO2 39.6 36.7 37.9 0.65 1.71$ 0.53% Fe0 30.7 27.5 29.1 0.77 2.68 0.71 Fe203 32.2 25.7 29.2 1.39 4.79 1.0 V205 0.47 ' 0.35 0.41 0.03 7.32 7.1 Cr203 0.24 0.06 0..1 is 0.04 34.0 10.0 A1203 0.35 0.17 g2403a0.04 16.9 5.0 Mg0 2.48 1.50 2.21 '0.23 10.4 1.2 CaO 0.14 0.07 0.Cî0 0.01 9.7 10 Mn0 0.20 0.15 0.17 0.01 6.o 6.3 Si02 0.53 0.10 0.23 0.13 - -
Grade 97.3 94.8 96.2 Fe/Ti02 1.202 1.058 1.135 Fe203/Fe0 1.160 0.837 1.004
(1) See Appendix I for complete data
'-•-•=, standard deviation x100
(2) Coefficient of variation
A glance at Table 3.3 indicates that the largest and most
significant variations are recorded in Fe203, MgO, A1203, Cr203
whereas TiO2 and FeO, althouth ^ignificant, vary much
less. The variations for CaO, MnO, V20, are of the same order as their
respective analytical variations and therefore must be regarded as
unsi&,nificant. Likewise, the data of Table 3.3 show that for the
average specimen, the maximum prade obtainable following a nearly
complete mineral :separation is Q6.2$ and its content of Mg0 is 2.21%.
Also, on average, V205, Cr203, MnO, Si02, A1203 and Ca0
cannot be decreased below 0.41, 0.11, 0.17, 0.23, 0.23 and 0.10$
respectively. The average Fe/Ti02 ratio to be expected for an hemo-
il:nenite concentrate from Lac Tio ore is 1.135 and that of Fe203/Fe0
is 1.004.
mean
-87-
'the results obtained on the 48 hemo-ilmenite concentrates
(Apnendix I) were used to investigate the cheoical variations in the
orebody and to define the inter-element correlations within the hemo-
ilmenites.
3.5 Chemical Variations of flemr-ilmenite in the:Ors
In the hone of discerning trends or patterns of variation
within the Lac Tio orebody, the results of Appendix I were plotted
on the cross-sections JK and Lfl.
Figures 3.3 to 3.8 ill_ustr-sjt;e the distribution of TiO2,
Fe and MgO in the deposit. Similar diagrams constructed for Fe0,
Fe203, A1203 and Cr203 are given in Apnendix III. The distribution
of CaO, NnO and V2 05 were not studied since they cannot be differ-
entiated from the analytical error.
Our investigation shows that the hemo-ilmenite is largely
homogeneous in composition throughout the Lac Tio orebody. A few
excefitions occur in regions of ?.ow grade ore (30 to 70% hemo-ilmenite)
where the levels of FeO, Cr203 and SiO2 are higher and those cf MgO
and A1203 are lower. No other compositional trends or patterns could
be detected in the orebody.
Lister (196 6) has rennrted a trend in the concentrations
of MgO, Cr203 and V205 from the ton to the bottom of the massive
part of the Lac Tio deposit. However, our study which involves a large
number of samples, shows that no such stratigraphie variation exists
in the orebody.
In the light of present data on hemo-ilmenites of Lac Tic,
Fai
LEGEND
% 70% Kzte.D-I:t+4zN.TE
/s
~~ ~o
1~-7
e1+~t~ %
u
1 , hë.
rr
►~:o -II.M.Er: IVE
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DiP SECTION OF
LAC TIO ILMENITE DEPOSIT SCALE 1"=C,00'
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S-0. l.evni
C~• +-• .. Ilia O.
T-37.5 ••• T•Zq.3 • . f . ...%., 1 • , 1 • •
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1• 1 • ~ ~ ~ ;:::.iitiil
...::::..:21.;&
' , • • ,, / i •: •♦ • •~ , - 1• • a ~ / , •; 11 • 1 1 • - • • ~ • I
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g3•, r~ï-93-9 •
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1 ~ •~. •, ` - 2l
• s , • • , \. • \ . • „♦ ~ e• • ~~ Ai♦
1.
~ ~I.• ~ 1 .1....
\
.-.
Fig. 3.3 Percent Tin_ in hemo-ilmenite concentrates of geological `section LM.
~
1,000
rjOO
~
a
o .a o d 7
-1 T-71- 8 'C--- •.—• •. ~ a
1 l•' a~`•~ ~:::;: 37;g
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v`. : :•: L . ♦
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r t • . / 1 ► •
••••mtriowto•••anr..
E:1
LEGEND
> 70% t;:N0•1Li\.Et31T~
30-70% HEW- ILMZNITE
ANOFtTI:OS! T F
LAKES
STRIKE: SZOTiONk OF
LAC 1710 iL.MEbdITE ©EPOSr s $Cqi.O? INs 6O0'
•
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Fig. 3.1 Percent TiO2 in hemo-ilmenite concentrates of geological section JK.
1-64-1 T-67-2 -•- .~
41.1.• `
ft. `~ ~ ~ ~
? -- ... ~
.. T-7a-2 Y-79-5 T-83-1 ~, •.- � ti
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DIP SECTION OF
LAC TIO ILlV1ER1 T t DEPOSIT sCAi,:: i -6o01
Fig, 3.5 Percent Pe in hemo-ilmenite concentrates of geological section LM.
1
K
~ 1.000
500
.1500
•••. .1•11••• Mim, `- -- -- •••!fi•91-4 ` ~....~ 7-83-i ..
~ÇQ►T SV%Q l~ ^•r-g7-1Q4 V
T-67-2 .., .c
o o 0
o o 0
LE:L~D
> 70°fo KEMQ-1L1AENITE
30-70% MEMO-1LMENITE
p,NOR T aOSiTE
LAKES
STRIKE SECTION
LAC a4'
LAC T dO ii L€ta x ra DEPOSIT
seAt.E, 1~~ zoo'
Fig. 3.6 Percent Fe in hemo-ilrneni.te concentrates of geological section JK.
- 2
` •• I I ~ . ( S^ ~ C' ^ J..frj 712 • • ~ •~ • :~.:•: ...: .+~~f r•:-: ~•~: ,i . r '-• Z I.~
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•~ `y. .. .~
• ~ . ~'~L'Z.~~
.I. • • r t I ...`. • ~ / • \ \ --~ ~ ;~;~. • / - + / ~ ~ ~ _ • $4,............4...:4:::::::&•~ . • . ~ l \ •i I ~ - • ,
\ i - y \ . / a / / • ~ .•
el \ ~ 1 • - • . + ' ~ • +
, • I • \ • • ; / 1 • ♦ • l , a L. • • ir / 1/ • . 1 .1 1• .. 1 •• •
1 • 1 r • .
•
T79:7 P,-ese~~ Sur 4ce_
•
\•-•••''." •• \•` • i 1 /" I •
M
_-
LEGEND ~ 7• 70% ~.a~0-!LF ;_a:sTE
DIP SECTION OF
LAC. T IG ILMENITE DEPOSIT SCALE t': Goo'
s'viv io ~;;.4?O-il Q2El4 iYF
.:.~ A.glciliiO~:TIS-
-Fig. 3,.7 Percent PTO in hemo-ilmenite concentrates of geological section LM.
Fig. 3.8 Percent 11g0 in demo-ilrienite concentrates of geological .?ection Jr.
mm....,- .a•z*.iMMWMMMsMsa+wMM.rr
A.1
~ i 0 0 0
~
o o o Ô
7 1,000
-. . - ? ~ Cv
~..**1`
` _ ••• ~- .....—.
T-54-1 T-67-2 ~ ......
7 71- 8 ~s ~ 75 .2J ~T-7 -5 ~ ~ i-,1-4 ~ g T fl3-1
. — 4 -- ~ ; sr...:.: a •n.C^nT Gable n•r.97 F 22p . —..~.~,,.—..:.:.... Lÿô1::.......:-:.•
: ... '2.42 `` `.t.i)t•0$tl-`~-r~ .~;~•.•::. ... :C` .
t.-- '' b, —._ . .~• zr--l~ .:::;'•':*:::::"::::•1:~.4.+4.::.•:.
i 'i. l .~
. ~ t w ♦ ~ t t
e I I - t • % } -
-'500
LEGEND
STRIKE SECTION 4F
LAC TIO ILMENITE DEPOSIT
> 70°fo F1EMC.-11.MEN!rfE
SO?O % HEf:SO-ILM:ENITE
A :oRYKOStTE
LAKES
.• -♦ .
SCALE I~s 60'6.
~\ • ~ ~ '
r t ~ :_ :'.~_1_
\ ~ d I~t- I _'~ ~_:. 2.35~7:
\ • / ` / -,l' ~ / • 1 ~'~~~ ® ',of
~ ;e i ~t• ,ti,~.J ....:.: za~1.. ..... e 1 i 1 i I \ f / - \ . ~ -f• \ 1• ' ! r %•• ::
: ~2:::. ~ 1 ` ' •;::: . :
: ~~ : ~•: : : .; :•: :•.; ;.::::: y ~fi f - t
' / \ # 1 ' +.'f ~ # 1 ! •% ~ # # ~ • • ••':.~.::.: ~:. .:::• • i+ ~
~ / ~l . , / 1 ; ;n1:1'7,.•-• •~ ~2+~ï`~1.!..
-, t
...%, . ~ ! 1 i ~ i ~ , i ~ \ \ .
II ~ $
. t.,
~ ! 1• = I ~ `~ o - ~ . . . ~ 1~
. I — / / / r.• I .. /
I +- I 1 • ► / ~ ~ • - t' \ • N.
/ ~
t .=..~•_.~,~~v.L~~-.r.
"1'6... j; •:♦:•' ••` ~ S
~ am! ,....r ~ .... _
r ~Y~~/ 7-7L. t~nn+iA
r47'2
~~-
+ •
.L 1 1 • ~ 1
1 "'s •
Sno
94
*re can conclude that the variations of hemo-ilmenite chemistry are
small and do not appear to vary systematically with depth or laterally.
The genetic implications of this conclusion are discussed in chapter IV.
3.6 Inter-elemenrt Correlations in Hemo-ilmenite
The formula of ilmenite may be more accurately expressed as
(FeMgMn) Tî03 with only limited amounts of Mg and Mn (Deer et al, 1964).
Chemical analyses of most ilmenites generally 'eveal variable amounts
of Fe203; this is due to hematite which forms above 1050°C a complete
solid solution with ilmenite (Pons.iack and Barth, 1934; Nichols, 1955).
The mineral from Lac Tio contains on average 30% by weight of hematite
and is appropriately described 6.s hemo-ilmenite following the classi-
fication of Buddington et al (1963). Small amourts of A1203, Cr203
and V203 ,are found in the hemo-ilmenite of Lac Tio; crystal chemical
considerations and microprobe analyses indicate that these oxides occur
principally as substitution in hematite where they replace ferric
iron. Similar considerations lead to conclude that Mg and Mn occur
as substitution for ferrous iron and are principally located in the
ilmenite host.
Because the chemistry of the Lac Tio hemo-ilmenite is almost
totally defined by the relation re203
+ (FeMg)TiO3 = 100%, strong
correlations are mathematically imposed on all mnjor constituants
such as Fe, Fe0 and Ti02. Examples of such correlations are shown
in Figures 3.9 to 3.'--':; ".where i.t is evident that, as the concentra-
tion of lee 0 increases, the amounts of Fe0 and/or TiO2 must decrease.
This negative bias is a consequence of the "olosed array of variables"
(Chayes, 1971). A priori, this correlation may be realize:. minera-
2 3
O
- 2.04 x -1.30
Corr. Coeff. 0.81
Syx = 0.04
0 0
00 0 0
0 CO
1.150
O 0 O O 0
0
0 0
o O
O
0.850
0.950 0
0
--1_,.., 1 1 1 1_.=1.••••_... ! __J
1.07 1.09 1.11 1.13 1.15 . .:7
Fe /T102
Fig. 3.9 Corre2ation f Fe/TiO2 With Fe~p03, Fe:.i in menite concentrates,
zwasniminaw;timmissmistr F.
` ~~~+~._~~~li
-96-
31.0
30.0
29.0
M 0 N N u-
8-9 28.0
27.0
26.0
28.0
29.0
30.0
31.0
% Fe()
Fig. 3.10 Correlation of Fe0 with Fe203 in analyzed hemo-ilmenite concentrates.
O
V Q
37.5 0 6
0 00 0
0
37.0 - 0 0
-97-
39.0
38.5
0
i i ---1 -~_ --- 28.0 28.5 29.0 29.5 30.0
% FeO
Fig. 3,11 Correlation of FeO ;pith TiO2 in aaal'zed homo-i1menite conctentrates.
38.0
CJ o
0
~0
0 0
y = 0.53 x 4-22.44 Corr. Co. : f. : 0.64 Syx = 0.49
o o
0 0 0
0
0 O
0 O 0 O 0
0 0 0
~
42.0 42.5 43.0 43.5 44.0 % Fe
Fig. 3.12 Correlation of Fe with Fe203 in analyzed hemo-il.menite concentrates.
0
G
30.5 O
42.0 42.5 43.0
% Fe
435 44.0
y = - I.Oi x+75.38
COrr. Coeff = 0.175 Syx = ,).58
30.0
29.5
0 d ~
e> 29.0
28.5
28.0
Fig. 3.13 Correlation of Fe and Fe0 in analyzed hemo-ilmenite concentrates.
-99-
O
O
- 100 -
y -0,34x447.90
Corr. Coeff = 0.73
0 0 Syx = 0.44
39.0
38.5 O
38.0
O ! O
O O O
37.5
37.0
O O O
O 0
O O O
O O 00 O
0
O
CO
I I I 26 27 28 29
% Fe203
Fig. 3.14 Correlation of Fe203 with TiO2 in analyzed hehia-ilmenite concentrates.
30 31
- 101 -
logically by a change involving principally the amount of hematite
in the hero-ilmenite. X-ray diffraction analyses of concentrates having
respectively the largest and smallest amounts of Fe203 indicate that
they respectively contain larger and smaller amounts of hematite
phase (Fig. 3.15). It thus annears that the variation of the amounts
of hematite anu ilmenite in the hemo-ilmenite concentrates is the
Principal factor responsible for the negative correlations amongst
the major constituents.
In order to circumvent the strong mathematical correlations
imposed by the variation of the amounts of ilmenite and hematite in
the concentrates, Fe203 was normalized to 30% and the concentrations
of all the other constituents were recalculated. In doing so, the
correlation between Fe0 and TiO2 was greatly improved. Indeed the
coefficient of correlation has Passed from an initial value of 0.61
to 0.97.
Attempts to correlate Mg0 with Fe0 using the analytical
data as given in Appendix I were not si:ccessful. Likewise, correlations
attempted using the calculated values for 11g0 and Fe0 after normalizing
Fe203 to 30.05 yielded no significant interdependence (correlation
coefficient of 0.15), indicating that in hemo-ilmenite of fixed Fe203
content, the i,1rr0 content of ilmenite is not simply related to its
content in Fe0 as the formula (FeMg)TiO3 would seem to imply. Pursuing
the study of the correlation of 1'1r;0 and Fe0. the amount of TiO2 in
the hemo--xlmenite which carries a much smaller analytical error than
Fe203 (Table 3.3), was normalized to 37.9 and the calculated values
for I•Ig0 and Fe0 platted. This process yielded a correlation coeffi-
cient of 0.50, suggesting a weak correlation, between MPG and Fen.
31.9%Q Fex03
'Or
Fig. 3.15 (104) hematite a,id .imenite reflections for samples containing respectively 31.9 ani 26.2 percent Fe203.
Continuing this study on the distribution of NgC., the author construc-
ted diagrams correlating the WO content of hemc.ilmenite with the
amount of gangue minerals in the originel samrle. This work indicated
that MgO increases nronortiona]ly with the grade of the ore.
In summary of this work, it may be said that the :-1g0 content
of hemo-ilmenite has a weak negative correlation with the amount of
Fe0 in the mineral and also, is positively co'relate,d with the grade
of the ore. These findings agree with an observation we described
earlier, namely, that hemo-ilmenites from the lower grade portion
of the orebody contain lower M ;0 and higher Fe0 than her,-•ilmenites
from the higher grade or massive portions o' the orebody (Fig. 3.7,
see also Annendix III).
It is evident from this study that MgO and Fe0 in hemo-
ilmenite are not conditioned only by the availability of these
constituents. A factor that most likely played a vital role in the
distribution of Mg0 and Fe0 in the ore is the nartitioning ^f these
oxides between hemo-ilmenites and nleonaste. sninels. Because both
these minerals contain varying amounts of Fe0 and Fe201, oxygen
fugacity in the melt undoubtedly was an important parameter control-
ling the r. artitioning of Fe0 and Mg0 in hemo-ilmenites . It appears
probable at this stage, that a study of the cleonaste soinel in the
samples :studied would shed more light on the distribution of MgO
in hemo-ilmenite; however, such work is not in the scope of this
thesis.
3.7 Synopsis of Hemo-ilmenite Chemistry
The chemical analysis a_ 48 hemo-ilmenite eo .centrates,
~~~!OnigiMUMININIMIC ieuriomasannumemrimminriarminirMilltarlffill11111M
MIIIIIWAIMEMEREIEMENIMMINMINIIIIMINNIssueseivaitaimimustinea
representing the entire Lac Tio orebody, has shown that the average
hemo-ilmenite contains : TiO2' 37.9%; FeO, 29.1%; Fe203, 29.2%;
MgO, 2.21% and V205, 0.410. Other oxides such as Cr203, .4nO, CaO,
Al203 and SiO2 are found in the concentrate, but together they.cons-
titute less than one per cent of the concentrate. Traces of S, K, Na,
Co, Ni, Cu, P and Ga have also been detected in the hemo-ilmenite
concentrates analyzed in this investigation.
The principal conclusions frac this geochemical study are
as follows :
1. Hemo-ilmenite from Lac Tio is largely homogeneous in composition
throughout the orebody. A few exceptions occur in regions of low
grade ore (30-70% hemo-ilmenite) waiere the contents of FeO, Cr203,
knO and. Si02 are higher and those of Mg0 and A1203 are lower.
No other compositional trends coula ue detected within the orebody.
2. The local variations of the Fe/'Tî02 ratio in the deposit can
probably; be attributed mainly to the varying amounts of ilmenite
and hematite n1-ases in the ore.
3. In general, Lac Tio ore cannot be ungraded above 96.2% by physical
means, since c.omoonertts such as MgO, V205, Cr203 and several others
are held as solid solutions in the hemo-ilmenite structure.
4. Generally, the Mg0 content of Lac TiJ ore cannot be lowered below
2.21% by physical means.
5. Comparing the analysis of the hemo-ilmenite standard prepared
(Table 3.2), with the analysis of an 87% grade ore (Table 1.4),
one notes that at lcest 4/5 of the Ni, 3/5 of the Co and 1/2 of
the Cu occur as atonic substitution in the hemo-ilmenite structure.
The remaining amour is are most likely located in the small amounts
II
- 105 -
of sulphides present in the ore.
6. it is interesting to note that 2/3 of the gallium occur as a solid
solution in the hemo-ilmenite. The remaining 1/3 is mainly associated
with the pleonast_ apinel where it constitutes anaroximately 0.1%.
7. Most of the Si, Ca, K, Na and S revealed by the chemical, analysis
of the concentrates is associated with small amounts of minera-
logical impurities such as antiperthitic plagioclase, tyroxene
and pyrite. These elements are thought not to Participate in the
crystal chemistry of the I,ac Tire hemo-ilmenite.
8. Considerations on the partitioning, of MgO and re0 in the ore,
leads us to believe that Le conditions of crystallization of
hemo-ilmenite, principally the oxygen fugacity :in the melt, varied
locally during the formation of the orebody.
wiltakeNEREMEMOMPAIII~1~;'~
io6
CHAPTER IV
CERTAIN ASPECTS OF THE PETEOLOGi AND ORIGIN OF THE LAC TIO DEPOSIT
4.1 Introduction
This last chapter proposes to review briefly the various
theories advanced by previous investigators on the origin of the Lac
Tio deposit and to discuss, in the light of our study, the implications
of certain mineralogical and chemical features on the genesis of Tthe
ore.
4.2 Metallogenic Traits of the Lac Tio Deposit
All of the economically important deposits of Fe-Ti oxides
in the general Lac Allard area occur in close association with gabbro
and anorthosite rocks. Such an association is but one example of several
similar associations throughout the world. In fact, the common associa-
tion of Fe-Ti oxide deposits with rocks of the anorthosite kindred
(anorthosite, gabbro, gabbroic anorthosite, etc.) has led most geologists
to postulate a close genetic relationship between the oxides deposits
and the anorthositic rocks enclosing them.
Much research and data on anorthosite and associated Fe-Ti
oxide deposits has been done in the last decade. As a result of this,
geologists tend to consider anorthosite and related rocks as a result
of igneous differentiation; there is still however, much controversy
on the nature of the parent magma, the process of anorthosite derivation
and on the mode of origin of the oxide ores associated with them
(Isarksen, 1.968).
107
,V„
Most workers on anorthosite generally accept the view that
Fe-Ti oxides ores are magmatic in origin as opposed say, to hydrothermal
or metasomatic origin. Hammond (1952) considered the Lac Tio deposit
as having formed from an ore magma and that hydrothermal activity played
no important role in the formation of the deposit. His conclusions were
based on the following observations :
(1) The presence of sharp contact!; between massive
ilmenite and unaltered pure anorthosite.
(2) The presence of unsupported inclusions of unaltered
anorthosite within the massive ilmenite.
(3) The general absence of minerals such as muscovite.,
garnet, tremolite-actinolite which are commonly
associated with hydrothermal deposits.
(4) The uniformity of mineralization which suggests
an approach to equilibrium conditions.
(5) The orientation of platy ilmenite crystals
parallel to the e_,titude of the ore sheet,
suggesting crystal settling in a liquid.
The Lac Tio deposit displays striking similarity to certain hemo-ilmenite
deposits in the Province of Quebec and in particular to the Brulé Lake
hemo-ilmenite depo:lit in the Labrieville anorthosite massif (Anderson,
1963, 1966). Both deposits occur as gently dipp::ng tabular bodies of
nearly massive hemo-ilmenite in anorthosite. The anorthosite host rock
of the Lac Tio deposit (cf. section 2.2.2) and that of Brulé Lake
deposit consist of antiper,hitic andesine (An45Ab600r5) with accessory
amounts of hemo-ilmenite platelets and minor ferromagnesian minerals.
AI:: AINUMEr MIIIIIIKOMMIMMOI
108
Such an anorthosite is classified by Anderson and Morin (1969) as an
andesine type anorthosite as opposed to a labradorite type anorthosite.
Both deposits display field relationships suggesting that the material
making up the deposits was injected into the anorthosite, and thus
would appear paragenetically late with regards to the anorthosite
itself. At Lac Tio, the injected nature of the hemo-ilmenite mass is
mainly shown by the presence of unsupported large blocks of anortho ite
in massive hemo-ilmenite, the sharpness of the contacts between the
ore sheet and the anorthosite, and in the upper part or layered portion
of the sheet, by the ;presence of numerous small anorthosite inclusions
in the hemo-ilmenite rich layers and the presence of crushed and bent
plagioclase crystals in the disseminated ilmenite layers (Lister, 1966).
These features have led Hammond (1952) and Lister (ibid) to consider
the Lac Tio deposits as having crystallized from a Fe-Ti oxide magma
injected into a gently dipping shear zone in hot anorthosite. Although
Lister (ibid) does not specify the mode of origin of the ore magma he
emphasized that the magma was not derived by filter pressing of the
anorthosite. As evidence for this he cites the much lower V, Cr and Al
contents and higher Mn amounts in the host rock hemo-ilmenite as compared
to the hemo-ilmenite in the ore sheet.
The trend of trace element variation in ilmenite and magnetite
with progressing crystallization of igneous magma is presently fairly
well established. The ctudieE of Vincent and Phillips (19510, Schwelluus
and Willemse (191+3), Caty (1970), Lister (1966) and Anderson (1966)
show that the V, Cr, Al and Mg contents of magnetite and ilmenite
decrease with progressing crystallization differentiation whereas their
•~.
109
Mn content increases. In light of these data, tbs lce er V, Cr and Al
content and higher Mn content of hemo-ilmenite in the anorthosite host
rock, compared to hemo-ilmenite from the ore sheet would indicate that
the hemo-ilmenite in the anorthosite host rock formed from a liquid
that characterized a more adver.zeit stage :f differentiat - than that
of the liquid from which crystallized the hemo-ilmenite the ore
sheet. Indeed, the high Mg and Al contents and the uniformly low Mn
content in hemo-ilmenite from the Lac Tio orebody may be considered as
a good indication that the oxide magma that formed the orebody exited
fairly early in the crystallization sequence that gave rise to the
anorthosite kindred rocks that underlie the general Lac Allard area.
Concerning the origin of the Lac Tio deposit we therefore
concurred with the views expressed by Anderson (1966) on the origin of
the Brulé Lake deposit, namely that, although the Lac Tio deposit
appears paragenetically late from field relationships, its chemistry
supports the idea that the oxide magma formed early in the paragenesis
and subsequently was emplaced or injected in relatively younger andesine
anorthosite rocks. Considering the growing amounts of field and labo-
ratory evidr;nces in support of the immiscibility of Fe-Ti oxides
liquids and silicate liquids (see in particular, Philpotts, 1967),
we visua'.ize the oxide magma that formed the Lac Tio orebody as having
separatsd early from the silicate liquid by liquid immiscibility. The
oxide Liquid may have settled at the floor of the magma chamber to be
later injected into overlying andesine anorthosite. From this liquid,
crystallized hemo-iimenite, pleonaste spinel, and small amounts of
apalite, iron sulphides and corundum.
110
,4.3 Crystallization and Evolution of the Hemo-Ilmenite Magma
Concerning the crystallization of the ore magma, Hammond (1952)
and Lister (1966) considered that the orientation of the homo-?lmerite
crystals subparallel to the walls of the ore sheet indicates that crystal
settling took place during; crystallization. Indeed, the discoidal out-
line of the hemo-ilmenite, their subparallel orientation and the "inter-
cumulus" texture shown 'ny the accessory minerals, in particular the
pleonaste spinel, are strong indication that crystal settling took
place during the crystallization of the oxide magma. By analogy to
minerals in stratiform or layered complexes, the hemo-ilmenite crystals
may conveniently be described as a cumulus crystal, and the ore as a
cumulite.
Contrary to Lister (1966? *whose analytical data suggested
a trend of decreasing V and Cr content and increasing Mg content in
hemo-ilmenite upward in the massive section of the ore sheet, our study
indicates that there is no systematic variation of trace element across,
the overall section of the deposit. Indeed, all attempts to correlate
the stratigraphic position of the samples studied with their trace
element content failed to reveal any systematic trend. The absence of
a trend in the trace element content of hemo-ilmenite that have largely
accumulated by crystal settling from the oxide magma may appear some-
what contradictory. A possible explanation for the lack of systematic
trace element fractionation over the entire stratigraphic height of
the deposit may be that the consolidation of the deposit did not proceed
through the simple and continuous crystal settling of hemo-ilmenite
from a single volume of oxide magma approximating the present volume
111
of the deposit. Rather, to explain the homogeneous composition of the
deposit and the absence of large scale variation in the distribution
of Mg, Mn, Al and Cr, we suggest that the Lac Tio deposit was formed
by the crystallization of repeated injections of essentially identical
oxide magma into a zone of dilation iii hot anorthosite. The occurrence
of other hemo-il.menite deposits in the Lac Allard area may add some
support to this hypothesis.
The injection of new magma into the zone of dilation would,
by intermixing with the crystallizing magma, dilute or homogenize the
liquid and mask the fractionation trends which might have existed
between the settling hemo-ilmenite crystals and the liquid. According
to this model, fractionation trends may be present over short sections
of the deposit, however, no regular trend would be apparent, when trace
elements are studied over the entire section of the deposit.
Except perhaps for small amounts of volatiles, mainly water,
which might have escaped or diffused into the country rocks during
the crystallization of the oxide melt, we envisage, similar to Hammond
(1952) and Lister (1966), that the oxide magma had a composition identical
with that of the present ore. From this liquid crystallized hemo-ilmenite
crystals and accessory amounts of pleonaste spinels, iron sulphides, and
rarer primary magnetite, corundum and apatite.
The lack of data, on the specific gravity and viscosity of
the oxide magma and on the rate of growth of hemo-ilmenite necessary
for the crystal to reach a size where crystal settling would commence,
renders highly qualitative the aescription of the crystallization of
hemo-ilmenite from the melt. It would appear probable however, in view
of the rather low viscosity of molten Lac Tio ore (1) that relatively
small crystals, possibly millimeter size, could grow from the liquid
and settled to the floor of the chamber. Under slow crystallization,
the precepitated hemo-ilmenite crystals could continue their growth
by interchange with the interstitial liquid and with the overlying
magma. This process of "adcumulus" growth (Wager, 1963) resulted in
centimeter-grained hemo-ilmenite crystals, having the characteristic
discoidal or pellet outline and interlocking boundary shown by the
Lac Tio hemo-ilmenite. Adcumulus growth of precipitated hemo-ilmenite
crystals was probably an important factor in reducing the fraction-
ation between crystals and the overlying liquid. The extent to which
this process could operate cannot be evaluated at this time because of
the lack of data on stratigraphically closely spaced samples. It would
appear improbable, however, that the homogeneity of the entire deposit
could be explained by adcumulus processes alone.
The distribution of accessory minerals in the ore, mostly
interstitial to the hemo-ilmenite crystals, suggests that these crys-
tallized last from trapped or "pore space" interstitial liquids. The
fact that the sulphide minerals are more or less randomly distributed
in the ore tends to support the idea that their abundance was largely
controlled by the amount of trapped interstitial liquid.
The relatively narrow compositional range of hemo-ilmenite
(1) Research carried out at the Q.I.T. research center at Tracy, Que. on the viscosities of ore and slags indicates that molten 90% grade hemo-ilmenite ore from Lac Tio has a viscosity of 15 ceutipoises at a temperature cf 1440°C. Although the viscosity of a natural oxide magma at temperatures 8f 1000 to 1100°C is probably much higher than that determined at 1440 C, this research suggests that visco-sities of oxide magmas are considerably less than that of silicate £)agmas.
113
in the Lac Tio deposit suggests that the conditions of crystallization
remained fairly uniform throughout the crystallization of the entire
deposit. The oxygen fugacity of the ore magma was probably the principal
factor that influenced the composition of the hemo-il;anite. We believe
that local variations in oxygen fugacity, principally due to gradients
established during the adcumulus growth of the settled hemo-ilmenite
crystals, controlled the partition of Fein and Fe203 between the hemo-
ilmenite crystals and the interstitial liquid from which principally
crystallized pleonaste spinel. As discussed, earlier in this study.,
the variable Fe0 and Mg0 contents of the hemo-ilmenite are probably
related to such variations in oxygen fugacity.
Our study has shown that primary magnetite is almost absent
from the Lac Tio ore. Indeed only one of the samples studied contained
accessory amounts of primary magnetite. This suggests that the crystal-
lization of the oxide melt proceeded under uniform and fairly oxydizing
condition. The crystallization of small amounts of primary magnetite
probably arose through fluctuations of oxygen fugacity in the inter-
stitial liquid during the adeumulus growth of the settled hemo-ilmenite
crystals. Primary magnetites appear to contain very low amounts of
TiO2 in solid solution. Microprobe analyses of some magnetite grains
indicate a content of approximately 0.2% Ti (equivalent to 1% ulvo-
spinel) in the magnetite. Hargraves (1962) also reported a content of
0.5% TiO2 in magnetite from Lac Tio. Lister (1966) also reported low
TiO2 contents in magnetite from other deposits in the Lac Allard Area
from which he inferred equilibrium temperatures of 550°C and oxygen
fugacity (Logf02) less 10-17. We believe that these data do not define
accurately the original conditions of formation of the deposit but
114
indicate certain intermediate conditions that prevailed during the
cooling of the oxide mass. It is considered probable that the very
slow cooling of the hemo-ilmenite body favored the migration of the
ilmenite out of the magnetite, thus leading to a low estimate of the
temperature and oxygen fugacity of the oxide assemblage.
4.4 Subsolidus Evolution of the Hemo-Ilmenite
Upon cooling of the oxide mass, the original high temperature
hematite-ilmenite solid solution intersected the solvus of the Fe203-
FeTiO. system. According to Carmichael's (1961) data on the hematite-
ilmenite solvus (Fig. 4.1a) the unset of exsolution for the Lac Tio
hemo-ilmenite took place at temperatures in the neighborhood of 800°C.
With continuing decrease in temperature, the composition of the unmixed
ilmen-hematite and ferrian ilmenite phases changed composition along
the limbs of the solvus, becoming respectively poorer in ilmenite and
hematite.
The composition of the unmixed phases of the Lac Tio hemo-
ilmenite was discussed in section 2.2,1.4. X-ray diffraction analyses
and crystal chemical considerations indicate that the xematite phase
retained approximat,ly 14% ilmenite in solid solution whereas the
ilmenite phase would appear to have retained very little hematite in
solid solution. Indeed, the smaller lattice spacing of Lac Tio unmixed
ilmenite compared to pure ilmenite may be explained as almost entirely
caused by the effect magnesium in solid solution in the ilmenite. The
composition of the hematite phase of the intergrowth agrees fairly well
with the composition to be expected from Carmichael's (1961) solvus
(Fig. 4.1a).However, Carmichael did not take into consideration the
Amato Loc Tio
HFmo - Il menite
Nei
Tem
pera
ture
1°C
)
200
LO 0.8 0.8 0,4
IMOMNINERIMMINIMENIMINEMBAVIIIIIIMINEMEIRMIRMEMLIERIEWIRIBMIIIIta~.®
115
FeT103, Mole fraction Fe203
•
Fig. 4.1 (a) — Solvus curve for the hematite-i meriite system (modified from Carmichael, 1961).
A
Fe203 FeTiOa
Fig. 4.1 (b) — Schematic diagram showing the extent of solid solution at low temperature in the NgTiO3 —
FeTiO3 — Fe203 sy stf i1. Line AB represents the
Lac TiO binary system.
u6
effect of Mg on the solvus; our data suggest that the effect of Mg
decreases the solubility of hematite in ilmenite. For an ilmenite
corresponding to (Mg12Fe88)(TiO3), our data suggest that the solvus
lies close to the ilmenite side of the system. A schematic diagram
showing the possible subsolidus relationships at low temperature in
the ternary system MgTiO3 FeTiO3 Fe203 is shown in Fig. 4.1b. The
field of solid solution is shown as stippled in the diagram.
Subsequent to the exsolution of the hemo-i.lmenite,subsolidus
reactions produced small amounts of secondary magnetite (Cf. Fig. 2.15a,
b) and secondary anatase (Fig. 2.19a, Although the strongest diffraction
lines of rutile Piave been identified in some powder diagrams from con-
centrate enriched in secondary magnetite, the commonest form of TiO2
associated with secondary magnetite is anatase. The nearly constant
association of anatase with secondary magnetite (Cf. Fig. 2.15b) strongly
indicates that the two minerals originated through a reaction involving
hematite and ilmenite.
Textural observations suggest that secondary magnetite and
anatase may be related through a reaction,'as follows :
(a) 6Fe203 = 4Fe304 +02
(b) 4FeTiO3 + 02 2Fe203 + 4Tî02
Combined reaction : 3Fe203 + 2FeTiO3 = 2Fe30 + 2TiO2 + Fe203
This reaction would lead us to conclude that the unidentified iron-rich
Am surrounding anatase (Fig. 2.19a) may be secondary hematite. The
common development of secondary magnetite and anatase along fissures
and cracks in the hemo-ilmenite suggests that circulating fluida Q probably
water, induced the breakdown of hematite to magnetite. Similar observa-
tions have been made by Kretschmar (1971). The oxygen liberated in this
INIMENM ME
117
reaction in turn oxydized the ilmenite to anataae and hematite. We
believe that the secondary magnetite and anatase were formed at rela-
tively low temperature. Experiments on the oxydation of Lac Tio hemo-
ilmenite at room pressure indicate that rutile and hematite are reaction
products at 900°C; at higher temperatures, rutile and hematite react
to form pseudobrookite (Archambeault, .1953).
4.5 Conciudirg Statement
This investigation has shown that the Lac Tio hemo-ilmenite
deposit is, in general, mineralogically and chemically fairly homogeneous
(Chapter II and III). A review of the literature on some Fe-Ti oxide
deposits together with the results obtained in this study has enabled
us to consider a model which attempts to explain the principal features
displayed by the Lac Tio deposits. The principal conclusions concerning
the origin and evolution of the deposit are presented below in para-
genetic order.
1. The oxide magma which gave rise to the Lac Tio deposit formed
by liquid immiscibility at an early stage of differentiation
and was subsequently emplaced by repeated injections into younger
solidified anorthositic rocks.
2. Upon emplacement and during the influx of new oxide melt, the oxide
magma was subjected to crystal fractionation whereby htmo-ilmenite
crystals sank to the base of the zone. Slow cooling is believed
to have favored conditions for pronounced adcumulus growth of
the precipitated crystals.
3. The conditions of crystallization remained fairly uniform
throughout the solidification of the entire deposit. However,
local variations in oxygen fugacity probably controlled the
partition of FeO and Fe203 between the hemo-ilmenite and the
interstitial liquid which principally crystallized pleonaste
spinel. Only locally did small amounts of primary magnetite
crystallized from the interstitial liquid.
4. After solidification and at temperatures in the neighborhood
of 800°C, the high temperature hematite-ilmenite solid solution
intersected the solves of the Fe203 FeTiO3 system and unmixed
to ferrian ilmenite and iimen-hematite. The hematite phase
retained some 14% Mol. of ilmenite in solid solution whereas
the ilmenite phase exsolved most of its hematite. Subsequent
to the exsolution of the hemo-ilmenite, local subsolidus
reactions involving hematite and ilmenite produced small amounts
of secondary magnetite and anatase.
- 119 -
BIBLIOGRAPHY
Anderson A.T., 1963; A contribution to the mineralogy and petrology of the Brulé Lake anorthosite massif, Quebec; Unpub.Ph.D. thesis, Prin.eton Univ. 1963.
Anderson A,T., 1966; The mineralogy of the Labrieville anorthosite,Quebec; Am. Miner. 51, pp. 1671-1711.
Anderson A.T. and Morin M., 1969; Two types of massif anorthosites and their implications regarding the thermal history of the crust; New York State Museum and Science Service, Mem. 18.
Archambeault M., Ci.aisse F. and East F., 1953; Hématitisation de 1'ilménite; Dépt.Mines Qué. R.P. associa avec le projet de recherche no.59.
Bergeron. M. and Rigaud M., 1968; Allard Lake ore and the Fe-Ti-O system; Q.I.T., Inter.Rept. 38-68.
Bergeron M.; 1971;Gallium in Allard Lake ore; Q.I.T., Res.Rept. 33-71.
Bergeron M., 1971; Review of published literature on Lac Tio ilmenite deposit; Q.I.T. Res.Rept. 25-71.
Bergeron M., 1971; Sulphur variations in Allard Lake orebody; Q.I.T., Res.Rept. 19-71.
Bosschart P..A., 1966; Report on a gravity survey, Tio Mine property, Allard Lake District Quebec; Q.I.T. file.
Bourret W., 1949; Aeromagnetic survey of the Allard Lake District,Quebec; Econ. Geo1.44, pp.732-740.
Buddington A.F., Fahey J. and Vlisidis A., 1963; Degree of oxidation of Adirondack iron oxide and iron titanium oxide minerals in relation to petrogeny; J.Petrol., 4, pp. 138-169.
Buddington A.F. and Lindsley D.H., 1964; Iron-titanium oxide minerals and their synthetic equivalent; J.Petrol., 5, pp. 310-357.
Carmichael.C.M., 1959; Remanent magnetism of the Allard Lake ilmenites; Nature, 183, pp. 1239-1241.
J
-120 -
Carmichael C.M., 1961; The magnetic properties of ilmenite-hematite crystals, Proc.Roy.Soc.Lond. 263, Ser.A,pp., 508-530.
Caty J.L., 1970; Pétrologie et pétrographie du flanc sud-est du complexe du Lac au Doré. Thèse de maîtrise, non éditée, Dépt.Géologie, Univ.de Montréal.
Chayes F., 1971; Ratio correlation, a manual for students of petrology and geochemistry, Univ. of Chicago Press, 1971.
Deer W.J., Howie R.A. and 7usisman J., 1964; Rock forming minerals, Vol.V, The non silicates; Longmans, Green and Co.Ltd., London (1962)
Dearden E.O., 1958; Compilation of Lac Tio geological data; Kennco Explorations Limited, Inter.Rept.
. Bearden.E.O., 1961; An evaluation of Q.I.T.'s non-contiguous claim groups; Kennco Explorations Limited, Inter.Rept.
Emmons R.C., 1943; The universal stage, Geol.Soc.Am. Mem. no. 8
Fleming H.W., 1961; A preliminary geophysical assessment of portions of Q.I.T.'s properties; Kennco Explorations Limited, Inter.Rept.
Fleming H.W., 1966; Report on the gravity survey, Lac Tio ilmenite deposit, District of Saguenay; Kennco Explorations Limited, Inter.Rept.
Foster W.R., 1955; Simple method for the determination of the plagioclase feldspars; Am.Mineralog. 40,pp. 179-185.
Ceode J.D., 1958; Field trip to Lac Ellen and Lac Grader; Q.I.T., file.
Gruner J.W., 1929; Structural reasons for oriented intergrowth in some minerals; Am. Mineralog. pp. 227-237.
Guimond R., 1964; Titanium and Q.I.T.; Can.Min.Jour. 11.
Hammond P., 1949; Petrology of Allard Lake ilmenite depo3its; Bull.Can.Inst.Min.Met., March 1949.
Hammond P., 19.52; Allard Lake ilmenite deposits; Econ.Ceol. 47,pp. 634-649.
- 121 -
Hargraves R.B., 1959; Petrology paleomagnetism of the Unpubl. Ph.D. thesis,
Hargraves R.B., 1962; Petrology Quebec; in Petrologic Studies
of the Allard Lake anorthosite suite awl ilmenite deposits; Princeton Univ.
of the Allard Lake anorthosite suite,
(Buddington Volume), Geol.Sac.Am.
Hughson M.R. and Kalman S., 1961; A mineralogical report on ilmenite hematite ore from Q.I.T., Allard Lake, Ouebec; Mines Branch, Investigation Rept. IR 61-60.
Isacksen Y.W., 1968; Origin of anorthosite and related rocks; Y.W. Isacksen ed., N.Y.State Museum and Sci.Serv. Mem.l.Z
Kretschmar U.H., 1971; A study of the Fe-Ti oxides in the Whites+to:;e anorthosite, Dunchurch, Ontario; Can. J.Earth Sci. 8, pp. 947-960.
Lindsley D.H., 1959; Magnetic anisotropy and remanent magnetism in hemo-ilmenite from ore deposits at Allard Lake, Quebec; J. Geophys.Res. 64,pp. 1565-1578.
Lindsley D.H., 1962; Fe-Ti oxides in rocks as thermometers and oxygen barometers; Carnegie Inst.Wash., Yearb. 62,pp. 60-66.
Lister G.F., 1966; The composition and origin of selected iron-titanium deposits; Econ.Geol. 61,pp. 275-310.
Lister G.F., 1968; Lac Tio 1966-67 drilling program, Tio Mine, Parker Tarp Quebec; Kennco Explorations Limited, Inter.Rept.
Longley W.W., 1944; North shore of the St.Lawrence, Mingan to Aguanish; Que. Dept.Mines, Prel.Rept. 184.
Mariano A.N., Pojasek W.J., White P.F., 1970; Some mineralogical analyses of Allard Lake ilmenite-hematite ore; Kennecott Copper Corporation, Inter.Rept.
Mines Branch, Ottawa, 1955; Sulphur elimination and beneficiation tests on the ilmenite-hematite ore and minus 14 mesh fines from the Quebec Iron and Titanium Corporation, Sorel, Ouebec; Dep.Mia.Tech.Sur.Can. Investigation Rept. MD3024.
Morse S.A., 1968; Revised dispersion method for low plagioclase; Am.Mineralog. 53,pp.105.
Nicholls G.D., 1955; The mineralogy of rock magnetism; Adv. in Physics (Suppl.to Phil.Mag.) vol.4, p.113.
•-, Osborne F.F., 1944; The microtexttüres of certain Quebec iron ores; Quebec Bur.Min.Prel.Rept. 186.
U Philpotts A.R.,1967;Origin of certain iron-titanium oxide and apatite rocks;
Econ.Geol. 62, pp. 303-315.
Ponsjack E. and Barth T.F.W., 1934; Notes on some structures of the ilmenite type; Zeit. Krist. 88, p. 271.
Quebec Department of Mines, 1959; Granularity differences in titanium ore from Allard Lake; Mineral Sc.Div. Test Rept. M-59-3.
Retty J.A., 1942; Lower Romaine River Area, Saguenay County; Qie.Dept.Mines, rrel.Rept. 171.
Retty :%A., 1944; Region de la -iviére Romaine inférieure; Que.Dept.Mines, Geol.Rept. 19.
Rodda J.L., 1945; Magnetic properties of some samples of Allard Lake type titanium ores; New Jersey Zinc, Memo M-435.
Ronda J.L., 1947; Chemical and mineralogical composition of Petit Pas ore, New Jersey Zinc, Rept. 1298.
Rodda J.L., 1947; Grade of ore in the Cliff orebody, Petit Pas area; New Jersey Zinc, Memo. M-514.
Rodda J.L., 1947; Specific gravity of Petit Pas drill cores; New Jersey Zinc, Rept. 1232.
Rodda J.L., 1947; Petit Pas ore beueficia.tion; New Jersey Zinc, Rept. 1268.
Rodda J.L., 1948; Beneficiation of Petit Pas iron-titanium ore by milling; New Jersey Zinc, Rept. 1338.
Rodda J.L., 1948; Distribution of copper, nickel, cobalt and sulphur in magnetically separated Petit Pas titanium ore; New Jersey Zinc, Rept. 1434.
Rodda J.L., 1948; Copper content of Petit Pas ore; New Jersey Zinc, Memo. M-558.
Rodda J.L., 1949; Gallium content of Petit Pas titanium ore; New Jersey Zinc, Memo. 679.
Rodda J.L. and Tennant C.B., 1952; Magnetic estimation of gangue iu 89Z and 93% grade Allard ores; New Jersey Zinc, Rept. 1840.
- 123 -
Schwellnu' C.M. and Willemse J., 1943; Titanium and vanadium in the magnetic iron ores of the Bushveld complex; Geol. Soc.S.Africa Trans. 46, pp. 32-38.
Vincent E.A. and Phillips R., 1954; Iron-titanium oxide minerals in the layered gabbros of the Skaergaard intrusion, East Greenland; Geoch.Cosmoch.Acta,.6, pp.1-26.
Wager L.R.,,1963; The mechanism of adcumulus growth in the layered series of the Skaergaard intrusion; Min.Soc.Am.Spec. paper no. 1, pp. 1-9.
The author sincerely appreciates the advice and assistance
given by Professor Gaston Pouliot of the Department of Geological
Engineering who directed this study.
The author wishes to express his thanks and appreciation
to the directing personel of the Quebec Iron and Titanium Corporation
for authorizing this study and making available all departmental
facilities. In particular, the writer would like to thank Dr. G.G.
Charette for his assistance in reviewing chapters I and IIIof this
work. The author also acknowledges with gratitude the help received
from Dr. F.D. Leipziger, Head of the analytical section at the
Kennecott Laboratories in Lexington, Mass. Special thanks are also
extended to J.J. Hill for his care and skill in providing the elec-
tron-probe analyses required in this study.
Sincere thanks and appreciation are expressed to Dr. A.N.
Mariano for his helpful suggestions in the study of the sulphides and
spinet and for ,droviding all of the color microphotographs contained
in this thesis.
Parts, of this research were rendered possible through grant
no. CR-251-71 of the Geological Survey of Canada.
A P P E N D I X 1
preparation and Chemical Analyses of Hemo-Ilmenite Concentrates
from Lac Tio Ore
Analyst : Quebec Iron and Titanium Corp.
Research Center,
Tracy, Quebec, Canada.
- 126 -
Preparation of Hemo-Ilmenite Concentrates
A total of 48 samples were selected from a group of 2100 core
samples obtained from the 1966-1967 drilling survey. The sampling proce-
dure in use at that time consisted in cutting the cores in lengths of
10 feet, splitting the cores longitudinally in half and crushing one
half of the core to -6 mesh and storing the crushed material into one
pint cans.
The procedure used to prepare the concentrates of hemo-ilmenite
required in this study is as follows :
1. For each of the 48 samples selected, a representative sample was
obtained by splitting the material stored in the one pint cans.
In each case, enough sample ':a.s taken to fill an 8 oz. bottle.
2. Each sample was ground between 150 and 250 mesh, in a cast iron ball
mill. Screening was carried out with Tyler screens.
3. The -150 +250 mesh fraction was washed and dried at 150cF for
12 hours.
k. Similarly to the procedure used in preparing the standard hemo-
ilmenite sample (Appendix II),each sample was treated with tetra-
bromoethane to separate the fel:dspers and - me of the micas. The
samples were washed with methyl alcohol.
5. The highly magnetic fraction of each sample was removed with a
hand magnet. The remaining minerals were separated using a Stearns
high intensity magnetic separator.
6. Each concentrate was ground under acetone to -325 mesh in a shatter
box, and stored in k oz. bottles. Sample weights varied between 30
and 300 grar,.s .
-127-
The 48 concentrates were divided into twelve groups of four
samples for chemical analysis. As a control, a sample of the hemo-
ilmenite standard (cf. Appendix II) •gas inserted in each group to be
analyzed.
l
Chemical Analy^es of Remo-ï]menites
Sample no. 2127 2199 839 1139 2150 98 119 139 280 392 221 588 554 609
r ~
TiO2 37.7 37.6 38.1 3 8.6 37.4 37.5 36,7 37.0 37.2 ( ~
37.5 " 37.7 38.4 39.4 37.9
Fe0 30.1 27.,5 28.8 30.1 29.4 28.0 28.9 27.9 28.0 29.2 28.7 30.1 . 30.6
r...._.. 29.8
Fe203 c alc
28.2 .
31.9 29.3 27.2 28.0 30.7 .27.6 30.6
----,---
30.5 28.9 29.3 26.9 26.2 28.2
A1203 J 0.18 0.20 0.17 0.33 0.21 0.19 0.21 0.25 1 0.23 0.24 0.23 0.24 0.20 0.21
! 3/205 , 0.41 0.41 0.41 0.42 0.38
i 0.37 0.41 0.40 0.41 0.41 0.41 0.40 0.40 0.40
. ._..._. . .
Cr203 0.24 0.10 0.10 • 0.09 0.17 0.08 0.06
- Mg0
0.11 0.10 0.10 0.14 0.08 0.13 0.06
~ 11.58 2.24 2.43 2.22 2.02 2.35 2.43 2.01. 2.42 2.12 2.35 2.16 2.20 1 2.08
Mn0 0.20 0.16 0.16 0.16 0.17 _
0.17 ' 0.17 0.16
_,_.r._._,_.,,.. 0.16 0.15 0,16
•__..._ 0.16 0.17 0.17
CaO 0.10 0.10 0.10 0.10 0.12 0.11 0.12 0.10 0.10 0.10 0.10 0.10 0.10 0.11
r Si07 -0.53 0.17 0.15 0.18
i_
-- 0.51 0.12 0.29 0.26 -- -- -- •- .
--
~~
~
Chemical Anal,'scs of Iiemo-1lmenites
sample no. 674 620 366 292 259 231 207 522 867 510 452 253 569 531
Ti02 37.4 37.9 37.4 37.5 37.6 38.2 37.8 38.0 37.9 37.9
I
37.6 38.2 37.8 '37.3
..,
Fe0 27.9 28.8 29.3 29.8 28.3 29.1 28.4 29.2 28.2 29.2 28.5 28.5 28.9 28.8
Fea 03 calc.
31.0 29.3 28.6 28.0 29.9 28.9 30.0 29.0 30.5 29.3 29.7 29.5 29.0 30.2
A1203 0.21 0.21 ~ 0.~.4 0.24 0.32 0.23 2 0.19 0.35 0.23 0.28 0.22 0.21 0.28 0.2?
V205 0.41 0.43 0.39 0.46 0.47 0.44 0.41 0.40 0.41 0.37 0.41 0.45 0.46 0.45
Cr203 0.09 0.09 0.10 0.08 G.08 0.10 0.15 0.08 0.08 0.09 0.09 0.10 0.10 0.13
Mg0 2.22 2.27 2.33 2.25 1.78 2.46 2.42 2.21 2.47 1.98 2.30 2.48 2.28 2.19
Mn0 0.16 0.16 0.17 0.17 0.18 0.17 0.17 0.17 0.17 0.17 0.16 0.16 0.16 0.16
Ca0 0.11 0.11 , 0.10 0.11 0.11 0.10 0.10 0.11 0.13. ,
0.11 0.10 0.10 0.1G 0.09 j !
.--
____ ____ ____ --- -- --- Sica -_-_
)
Chemical Anal7ses of Hemo-Tlmenites
Sample no. L498 504 687 705 911 11006 1072 :1164 1173 1242 1289 1350 1199
s.
1228
37.0 36.9 38.7 37.4 37.7 36.7 38.3 39.2
------
38.0 37.8 38.6 TiOz 1-39.2 38.0 38.1
Fe0 30.5 28.8 28.9 28.4 28.2 28.7 29.3 28.3 27.8 29.1 29.6 28.7 28.0 29.4
Fe 03 ca~c.
26.9 29.2 29.0 30.7 31.3 29.5 28.6 30.3 32.2 28.3 27.6 30.0 30.7 28.5
Ala 03 0.21 0.22 0.24 0.26 0.25 0.25 0.33 0.23 0.23 0.26 0.22 0.25 0.26 0.32
V2 05 0.41 0.40
L-
0.39 0.37 0.39 0.38 ' 0.41 0.38 0.36 0.41 0.44 0.44 0.37 0.48
Cra 03 0.07 0.10 0.09 0.11 0.08 0.10 0.09 0.09 0.09 0.17 0.09 0.10 0 09 0.15
Mg0 2.32 2.29 2.29 1.78 2.23 2.17 2.26 2.37 12.19 2.40 2.46 2.23 12.44 2.16
MnO 0.17 0.16 0.16 0.17 0,16 0.16 0.17 0.16 10.18 0.16 0.16 0.16 I 0.16 0.16
CaO 0.10 0.10 0.10 0.14 0.11 0.12 0.10 0.12 0.11 0.11 0.10 0.10 0.08 0.08
Si02 0.19 0.44 0.13 0.28 0.18 0.16 0.10 0.16 0.14 0.1.A 0.19
0.11
Chemical Analyses of Hemo-Ilme:.ites
27.13 2052 2023 / 2172
37.4 38.4 37.4 39.6
28.7 29.2 30.0 30.7
30.5 28.7 28.2 25.?
0.23 0.23 0.21 0.17
0.38 0.37 0.40 0.35
0.08 0.12 0.12 0.23
2.33 2.31 1.70 1.50
0.19 0.20 0.16 0.16
0.11 0.09 0.09 0.07
0.17 0.14 0.52
rxn0
i
MgO
Ca0
Si;
0.18
28.7
0.37
0.09 0.10
i
29.3
29.5
0.25
0.41
0.11
2.33
0.16
0.13
calc. Fe2 03
1313
2.07
0.20
38.6
29.8
1348
38.5
Kennecott Corner Laboratory,
Lexington, Massachusetts, U.S.A.
-qansssermm. IIIIINIIIIL ~®
132 -
. .A,PPFNI)IY. II
Prenaration and Chemical Analysis of
an Hemo-Ilrienite Standard
Analysts : Quebec Iron and Titanium Corn.
Research Center,
Tracy, Quebec, Canada
and
- 133 -
Preparation of an Hemo-Ilmenite Standard
The nrocedure used to nrenare a standard hemo-ilmenite sample
from Lac Tio is as follows :
1. A 40 lb. sample of hemo-ilmenite ore was hand-picked on the Q.I.T.
ore pile. The material was selected in such a wary as to avoid the
gangue and host rock minerals.
2. All the rocks susceptible of containing important amounts of
magnetite (Fe304) were re,iected. This selection was done by
using a hand magnet.
3. The material was crushed to -1/4 inch using a jaw crusher and was
farther reduced to -6 mesh in a cast iron mortar.
4. Tne sample was ground between 150 and 250 mesh in a cast iron
ball mill. Screening was carried out with Tyler screens.
5. The material was washed and dried at 150°F for 18 hours.
6. Most of the feldspars and some micas were separated using tetra-
bromoethane which has a specific gravity of 2.97. The heavy fraction
which contained mainly the hemo-ilmenite was washed several times
with acetone.
7. The highly magnetic fraction of the sample was removed with a
hand magnet.
8. All gangue minerals were separated from the hemo-ilmenite with a
Frantz isodynainic separator and a Stearns high intensity magnetic
separator.
9. The hemo-ilmenite concentrate was f;round in acetone to -325 mesh
in a shatter box and rendered homogeneous by mixing in a ball mill
container for 36 hours.
The concentrate thus prepared contained less than l% of
mineralogical impurities. Microscopic examination under immersion oil
showed that the principal impurities were rare grains of suinels,
nyroxene and feldspars. The low amounts of SiO2' Ca0 and PJa20 and K20
reported in the analysis (section 3.3 ) are most likely due to
these impurities. We believe that these elements do not narticioate to
the crystal chemistry of Lac Tio hemo-ilmenite.
~
Replicate Analyses of Standard Hemo-Ilmenite Concentrate
)7
Analysi8 1 2 3 4 5
no. 6 7 8
~
9 10 11 12
,
lverage
Ti02 37.4 37.4 37.6 37.6 37.7 37.6 37.6 38.0 37.6 37.3
~
37.6 37.4 .37 6
FeO 28.3 28.2 28.0 28.4
'
28.3 : 28.0 28.2 28.2 28.0 28.3
--~-----.----^-~--
28.4 28.3 28.2
Fe2 03 30.2 30.3 30.3 calc.
29.7 30.2 30.7 30.6 30 2 30.6 30.3 30.2 30.7 30.3
A1203 ' 0.22 0.23 0.21 0.21 0.23 0.21
-..-=
0.23 0.23
~.~.-
0.26 0.22
- 1
0.24 0.25
•
0.22
•
Y205
t
0.43 0.41 0.41 0.43 0.43 0.39
.........~...
0.37 C.43
.-~ -
0.41 0.44 0.36 0.42
{~~
0.42
Cr203 0.10 0.10 0.10
~.~...+~
0.10 0.10 0.09 0.10 0.10 0.10 0.10 0.09 0.09 0.10
Mg0 2.42 2.47 2.40 2.46 2.44 2.39 2.37 2.41 2.4'2 2.43 2.36 2.38 2.42
Mn0 0.16 0.16 0.16 0.16 0.16 0.17 0.16 0.15 0.16 0.16 0.17 0.16 0.16
Cao 0.10 0.10 0.10 0.11 '0.10 0.10 0.]0 0.11 0.10 0.10 0.08 0.08 0.10
~ - - - - - ---- '
APPF,NDIX III
Cross-section Diagrams Illustrating the
Distribution of FeO, Fe203, A1203 and Cr20,
in the Lac Tio Orebody
Note: The location of the sections with respect to the orebody
is shown on Fig. 1.10 p. 28.
M
. ~
T-~7-9 ~ ~ ~~~ ~,.,•,—...,s~ T83s •,
~ T-,3-9
T-87.S-~♦ f.ga ~ ~ 1~~ :12$•9 j.• ._1N,
_ ' • ~ • . A ; ~,. •: ~.'- ;~; •, ;;,: ;• ;_:, •••5;1 - :7• ( 'Ji •.:~: :17:1J 1'
a,/ • : I • `i :ti'' '~~• ] V~ r1•r r• A o ~ 'i::•2T.9
~ ~
5Qq
•
LEGEND
~ 70% n;.'-.ht174LA;âWiTk
30 -70 % 6i F.p.: O• i L.t4 E N ITE
AN ohi ii031TE
DIP SECTION
OF
LAC TIO ILMENITE DEPOSIT SCALE 1/=600'
Percent FIFO in hcmo-ilmenite concentrate: of r eolocricai section T'- .
A
*. I 1 • /
• 21• r • •
• ; \ ~` 1 ~ • •
••` %`1;1I . .~•..„%•
1: 1 : ; .~::• / 1 1V•
.id•— 72:5 • =>>~e .; .~ :... 3ô
• g je.
1 ;1~ÿ ~+.•.
' 1 ♦` •♦ ~ ~~h~Î . / •/ '• ~~ ~+~ti
Ar •r~11 I
J. ♦ • ♦ • .
•• ,", .' • , • ~1~' • ~ ; 50
•..?!.._•.2. .. • • r• Q
`_-' ♦I r • •-- • • ~ ~ 3ô.1 ~??,.'a•~. 11 . '
--' • •jJ~ ~v•.'`~•JI. ~ar ~g..~~i~ n ' ~~i 1
111 I ~ •. 29.y~ `?:~• • / 1~
.Y.11..... ~; ~ Ir'1•
130.=?•' %•• . / •
_ ; 1.~••;::: 1: ,~1 I
2•~-_:,' ~I,1r . 1 ~
N • ~}; '::; .:~:'t }~•~ , I ••: 1 I
~= ? •v':;.;';•: :~:.::: ~ ~ ! 54^
, I. . v ~f 11`.::.4:%.:".....•.4..:..
• :~~•::$ ~.•.ti•::~:*:~.: 1 •./~ a •• r 11 I I I i ~'". •:i::~: •: ;: :•:.:':.•.: •.1 , r• ~ I1 ~ 1 A 1 ♦ ~ • w I ;r.; :; : : -.4:,:-..L w ..V.:? 1 r
I~ r ♦ '• .... .
,„•• •
, I ~~•‘ ; / ` ♦ •~ ~ 1 • 1 1 ♦ o ` 1 r • r i I I I• 1 I• r ► I• ., 1
1•• i~ •11, • i, • 1 11 . .p A • 1 • •
T797 iPresert Sur
I--
.x o o 0
r o o a d
~ 1.000
C ? ~"
T-64-1 T-67•2 T-71- g C+• ? ~. v 7 7...•••• ~ .~ 'ammo ..•T-gJ-4 ~ T-7g-5 T-83 _
~!!2 ,,~..,;':: 30.6 Gvrt T 871
1:-•r 2• ~ c
. ~:1• 91 ~;
-+* 19. ~ _ _~: : r: : : : ~ : . t -_ ••
'~ -L.~• . r~-. i.~i~v::::::~
.•5• '•Y.ti•.. wû~~••_?+:. •ji~ •l.•:. • 1r.Ÿ
t~~• ._ •~{•...___•t Fi_ _ __..._-._'^~'r,~•1~+.::_~':••~':~ ~'.•.~..~:•,~~~.~:~ :•yJj~%Î:
T4:-9 ...R. ert-^:. ch.t .+i;.
500 _ ~ ♦ ~
4..4:";;;.:C
• r r Y \ \
11e% ~ ~ ~ , ♦ i 1 ~ . s I % I.- \ . ♦ 1 i
\
' 1~~~•:~27•9i+'I 10 \ ~
1 # \ ♦ ♦ ' ~ \ 1 i ~/ ~ ~ / . •~\- / . ~ r ~ ~♦ I ~ I
~ I \ ~ . ~ / ~ , ~ .; ~ I 1 ~ •e1 r / 1 I : • / 1 ~
• \ / .7"1 "..7.=% - / % / ,
.I?_~
~~`' 2 •y.:~i ia .:•:•::~ i,[_i_.
/ - ~~ : : • ~:::•: :: : :: ® : :::: •,;'%
t ;t;~:~„ :.,••.;~~ . , , \ ~ / ` \ ► - ' ~ / .
~ r ~ . I .
► . / !
~ / ♦ I I ' I ♦ ~ •I r ~ \ .• I .• 1 _ - • i % -
-
•
I ~ ~. I \ I ♦ / . I 1 J I r _ / 1 ..
.. / 1 - ' .___s_ 1400
LEGEND
> 70% ~.cPAO.ILME11tTS
30-70 % H.r••It"~G •• 1L~/,E hllëE
AR1ORTitOS1TE
LAKES
STRwNEE SECTION O~ r
LAC 110 Il.4lPENI T E DEPOSIT SCALE 1~s SsO®`
•,\ . \,
EE
Percent I'eO in hemo-ilmenite concentrates of ;;eolopi.ca1. section JK.
11121EIMINBINSIRFAMIR
4L
......____-----A .~/•• ' Y'"5rn`I:92•6 •
; •I• i.;:::: :C: ~~ svf~n~ 1 — u / % ~:ti• :;:: :;::~-'r. ,~f:ii'~':Jÿ. :~.~~r+~?~►••~ <••• •••
, ~ ~<'~ :j ` :j%i ~ I , ~::•r +'
..: i t w ;64:...%
' .t • •• • w • • •T• ~7 ~ •••.,... `` 1 r 1 1 • .• .+,• 1 • • • • 9 ` ..~ .. —c:
. 1 ; It•. ._~..5..•_ T-E7-5 ~ 7-e3-3
•, L
.r ~ • ••1 ' '♦ • , I .
• • ♦ I ' ü•: "::: : t-
I 11 I • , , ~::•:~29.5 ~ I~._,. ?25.12::••••:.:::.
.~ : 1. , _,1, ,.,
•~. 506
POND
0•
w /+ ~• ~ ~/ i` ' • / ~ , / 7..•..:•ti, Fq7 • I • ~ .. • ~ I • + .:• ' .• • -.4—. \ ~ ~''1~••~,',•:
/• 1 ~ •.1 ~'v~'t30 _.T }:: 1 .. r I • i • ~ i , ~ ~ ~ ~•~:
r . ~,.?Z `+ !' •.1~~•..;:: :IZ7.6~; • ~ 1 • • ~'~ ::r~~.: :~ ~ 33.'s ' . r • ~' '•sâ0.6f: ` .
••
• % r ~ % I ♦ ✓ . ,
T.g3•5 T-33.9 T.79 4.•
T-79-7 Preset Sur~ee
I . •
, O I a ~ . .~ -.~.~ -.-.: -.. . •. I , ~' v, ~• • ~ ~ ~ • ~ i ~ •~1'• I A I • • • •
I ♦ • • ; / w , •; 1, • 1 I • • I I ~ , • • ~ • , 0 . 1 • + • • , • • • •
I. i 1• •• 1 I I /, • I • • t 1 • •
• • 1' • • •;,:y. — 'wtr-Z~• 1 • , •,• ~ - •=..• 1 1 , • , • I
..._•• • .. •••
• ~ ~
v .~~;• ~/ .
••A I . ~• • 1 • 1 , 5a0 • • ~r. C •• . i
9a • •
J.~••.1~ • • 1 r •
• . , ..~ +; • ~ Ib`s1.1-41 5\: I 4.~„• . . ~ • ' .•.' ',. ~ ~ r~ ~:'" "•
/ • ~ ~L'~
~'•~•''~~~•~'~''~•~'~~'••''~''•~'~
LEGEND
70% Nanr.0-144041TE
30•70% NEMO•II.MEtsPa
ANoRTW05117,
DIP SECTION OF
LAC TIO ILMENITE DEPOSIT SCALE 1 6001
Percent of î"e203 in hero-iltaenite enncentrntes of reolc+ric.ù section
~:~... .
,♦ ♦,
LEGEND
2> 70% H:iAO.ILMENi7E
3070% KEI.90-ILMEN{TE
ANORTNOSSTC
LAKES
STRIKE SECTION OF
LAC i10 ILtVlENI d E DEPOSIT âCALF 1"e 60O'
K
z O o O Ô
7 1.000
.-. ? .~ ~ ~ ~~ ow, 7-6"
44.
.. ~ - ...men. ... ..•7-9~-c, T-64-i T-67.2~ -- T-71-e Ca T-75-2J T-79-5. ~ ►
r .—• '~
• Z Z ~ 261) , fla~pcn-r S~•p~~.~.~~T-87-fo•I•:. :•r
► ~ ~ 30.5' 0.:;3:-.•;:::;: d• {~ ~' ~ ~:::•:•:;;'~~ 30: ~ '
:..:•^ ......
~~ .44;44.;." :.`.' .'~•_~__'--M ~~•—_, " •~•,
.• j~'!<; •:r~~~c:.:.;...
:290 ....:::
~ ► i. ~ ~ - I ~~ •~ ~ ~ •: •: : .. :•: . ï : : : s ~
- ~-♦~Lx " : •:::.;
•
/~►
% ► +, ~ ► ► I •~~•~,;~'•: ~•ïry4er ' ~ :ti•:•::•: ~ 30.â i'~•~ ~é;;~ =~~•e sr
..... •
~ / ~ ~ ~• ~ ~ + ~
~ ~ ~ ~ ••• I \ ~
~. ♦ I .. [y e, % ~
. erei///- S. ,,e i r`, :
0
..y00
..
, i
a,'::i • 1 ••% r
_ ►- .. • , f ~ ` - -• ." /`
►
► ~ •_
~ , , ► ►
+.~"_ ► , i. • . ~~ , 1 r . / 1 -.. / ~
.:...: :•::• i •
► 1 r r~: ~
::Jw:i~Ï ::;:'•: i , ► .
l / ♦ I ♦ ! • ~ ► .I ~rÿ • •~ ► i ►I\ ~
♦ ~ ~ i
~_ f;— /.•
J ► '♦r,I
.4.I►
•I 0. •
/ -
► •
/' I.• -
44 r .4.1
.
44.
I* % / ♦ / r. )I I' I
,/I . •• I / ..,/ ► o•'
.. / 1 ~ — • ,k,
... -.., IRM. ... .... !r O.»
•r
Valk/V.74.'7L.
L,~ , ► .-c.~~
►,! , 1
SOO
Percent of Fe203 in hemo-ilmenite concentrate, of gcolo;tical section •TK.
i
L t~t
~
__ .. ▪ ,._ _3
:•••(':a
S- ai~\.^~
.;< •• v. / v . : .,.,; * • ~7:: : . ~ ~ / / :C~ • ~' !.~ 1 /• ~ •~wL:_iÎ 1-~ ;r~T ' / ~ ‘ • / I l ♦ - ,•,a 1 ...♦ • ♦ ♦ . '
t `♦''`,♦ / ' , ♦ I ,':.~:
♦ % 1 % / =•- ~ -) \ i `. /• ♦ • • ,~.
/ / .\ / . 1 ••••.1.:. •. 1 • \I~ • • ~ •~,~'~'~ ...'': ::: '•: ♦ ~%
•;'1 Î~♦ ';Ï ~.`: •
Z \ • ♦ • ' \ I• ` • ~• ; '::
• ~ ~ ; % • I ;~~ . l • ,l~ i
.• _ ..n~~ :"% ~
" r = ~c~ +..! ♦
-~%-9 + `~~ ~. ~ .• •.. ~ 7-33.5 T ,S3 -9 : T-;I?•5~~ ~ T-E'-s
••• ••• sm.
Y
. I• / ♦ .~•.; . ï
t 7,/• /~.~ ' • • ••• t • 4•.~ , ,` ~ ; :`;.`.
• ~ ' , / •~~ .• v~ •:: ,t ♦♦ ~~ 1 rÿi~i ~• •
% / . / /
/ /♦ ' - `,
;
n.ÿ :/^~':~{:• :.1~~~~ '~: ,:w:ÿ ‘~' 1_ / •: ai'^
~~.0•., , ~~ti~ v.• .` •. —/. • •• \ . •
• /. • ~ ` ~ • •'• '•
•'• '' =K'' ti`Nj. 1 .f t • 1 / • I I •• 1 ••\ `'4 :ï ~ • :• •''' •' •'• \ •• / / • 1 • i~ 1• • _/ . ±••` .
~ww•~4•'a / I ♦ • ♦ .•
4 / ~ / • •. •• •♦ ♦ t • ♦• _ • I • 1 ♦ I 1 \ - • • ~ • / • / 7 • , , ~ I • • 1 • 4 • • • ♦ •0
• 1
4 • • • • r • 1 • l 1, . 1 •• . ♦ t I • ♦
.• 0
• •
•
/ A . / ` ♦ •♦ \ 4 ' ~ .•• . ♦~ /, / / / • / ♦ ♦ 1 /
%~r /♦ • ♦ ♦•: ♦ • ', ' $O0 • 4♦ 1 • / , . - . • ♦ -
,'..
• r'. •3 . • ••♦•• •♦.. ' .. . •
Otl. .. 0.18 • t :~. • • 4
•. ti z
ti..`~' : ..:'i.:.. :/ J^,
:•.
f:•
1.7.Vi . ' 1 • % '•~, .•. • üüv • . `. \ 1 '.
• • : ~ ..d• . •": .r.~ •w %
• • . •
r~ _.....^ „-_ . . • O.it ~,t..~• ~ ~ 1 ..:î.)• ' • . çnrkll!;r•;
``^~ `•• `•• • jr.17 ...•
T-Tj./, 7%97
Pre,rr z Surface.
••„ • / \/• , I ♦
♦
MIA
'e.-.•`•.•/
LEGEND.
~ !O% kbNI -1:.W;_WRE
30,70% NE::30-iLr4dtutTC
AltiOttTKOstri:
DIP SECTION
OF
LAC 110 1LMENITE DEPOSIT SCALE t"=6001
Y Y
Percent Al203 in hemo-ilmcllite concentrator of reoln ~•ical section I.,. 1
J
~ ✓ O 0
~ é
2 o o o o
ta boo
e~~? r -,, ? ~ ..▪ lb ✓
` "."4"...".% ~ ,~ .......m• .._ ~.. ~. ~ "T.1.91."4 T-64-1 T-67-2 r 7=• 8 ~ :1 ~ ~ ~ ...T-78-'Z _ 79-5 T-83-1 .► ...
.♦ `~ ~
~..t.,-.. 1. .r..► Dvl•S.CryT $at•On.-^i.-g_•-r .:.:~.... 8: t • ,‘",„0.2 p . i..-...,........,..,, O. IO~~: .
-,- r ` ~~ 2g
ri e.21~; ;=~ .~.: . ::::. •::: •ti,
..• ...:,..-:-:•.•:•::•.•:-..:r.':'•:•:•••••' '~• Ÿ • ' -~ . . ~ ' . ~_ • •_ __.. _ _. , ~~~~.~^ • . I0. •~•::...••~.;- ..••~• ~. ~ 'L ,I• +'.` .. ..i~...•'.•~. •,'^•`~y~;•:Ï::•::::•:::;.
ç / 1 .. 1 r~ 1 ~,:i ~~~ 0.23 ~:; . . .::1:1:141 •- .• + _ . . .e e a _. . . . _. . . 0.3â.f'_'"~i L~i •: :~ ,~ •
. t . 1 ~ ! \ 1 /
, t . ~ ..1....% . t t. ' / t
r / ; • 1 ' 0 .e1 1 ' 1 t ~ / tl'•a I / ~~•' :•::.:::: :: :::.~ ... • - ~ :'~L:.„_:~: :._:--1- , . ~ ti ' /. / i 1 s ♦
, ~ r ♦ a 1~ ~ % ~ ' ~ -/ ~ t ' t 4 t ` _ ',. /~ j t / // 1 ~ 1.. I ` I t - /
/ • ~~ • 1 1 ~ r t - `' ~ . . .. t- • " t ~ ~ - ♦ / 1 ` -'~ 1 ♦ / r 1
I _ / t r - . t - / .. I ~ 1 r • ♦
1 ~,`
4...d......1.;;; M = ♦ l t 1 ., 1‘ ...•
•Z; :.... / r ' ~ t 'r .•1r 1 / ` / ..r;-
/ ,I - 1\/~ ~ 1 r t
C00
-500
1 ~+;i. .~ .•~r ~ ~
97-7t,~ .;.
> 7o% 142140.1WtwVlTF
7.0-70% r.arf,0-11.MEwIz&
ANORTKOSI T E
lAX~S
S T P4.KE SE=C T IOM O~
LAC ~i 6G tLMEN9 ô•L: DEPOSIT SCALE t~• 6oe'
Percent A1203
in riemo-il.mnnit:e concentrates of r:eolo~ical section .TK.
~~♦ ~ res•..,-~ ~i•ô ~ ♦ • I r ;:,
: . ..: . _ ~ Vh%I ♦ / • le.:
r
S0f)
•
♦ i \II
\ . ~
• • :i%•:::::: I I
',1~7GV• i I ~•.°♦
_______ _~
.. ~ ? /' / ~ ? `. ~. ; r~•: : . ~ r; I ~~ ~ .. ~ ? ...... ~ ~ ~ ~ •.. /• ♦ iL'i•~ïr•'••.•~;i: ~ - ~ = Î~• 1 `;t?'•
• ••• •. I r .L ~. ♦ ~
~ ~• ,• a`ÿ. :::~:'... Q9 •••
• I I ~ l. ~ .~ . ~ .; •. .
I - •44: I / • .• I •r` ♦ I•
• 7‘,„~ • / • 1 - .
r - • - ~ • .. - \ • I
t \ \ • •
LEGEND ~ 7o% 1+-m3at:-wITE
Jd-To% 14E.u0-iLc4ENrcE
`• IoRT•tovrrE
T797 P4eS~•hZ Sv
• .••~~,..• •':': • •
r~~•j,• T~~ •~♦ • I•! '1 `
'•~~5=. • ?
~.~ •
I' • n`-•,:•.~n
• • ,~ • ~• • • ...t.i ~/.,^.
y• ~,~ ~~• t . •.{ ~.. .- :-•=~ • c •• • ♦ • I •
,r~4~J' • f ~I r•' •::•• ~ i r i • I •• ,....: . ....... .. -- • - • ~ I •
~.~t I • . ~ •t t ~! i
• i r •~!t••~" {: :~`i • •~-':~:~ • ~1 / - ~.Q
~, ~« ~ 1~•.ID .Tr-r
~• i •: i • .I. •. r ~~ ~•~~~'•':~:::; :Vt~:~ 1N t I• • 1 I
~ •\IIv ~•sr/ •: .~ ::•:'::•::•::iJ•~• ~ ♦r i 1
'44;
I - 1 ~ ••• ..60""b6., Ii I•I I. •- •• • i / / • •• I • • ~ i • • •• -•- • ~•
� 1 •
~ ~ - 1 i • -• ~ ~ • - Ir i' •• • r • I • 11. 1~ .I I ..
• • •• •
DIP SECTION OF
LAC TIC ILIIIIENITE DEPOSIT SCALE Ii1=40o°
~
!i ri7
• I I 1 l , •; • i ~
5 r • / / •
/ • ~ ♦! I• I \ 1 • I • • I ; I
! o J i ♦
2t ♦
h$7-4 ^~~~ C.• .,.•.._~ ~T.g35 •• T•83-3
nee.
I_ I • -'•
~"r • I ♦ - •M•r r -•• •
"•••.?~ -• I ! •
• t~~ ! .• -•:: I• '•C:~: •• • - • 5% • f ~ ~ ^• ~
Percent Cr2O1 in memo-'.Lmeni ;e concentrate of reolor ica1 section LM.
dome WWII Ole 0.1. 01,0 OM.
•••••
1741. (TPP:.P'ih
•
. , ••• •••:e
• • • „ •
, • ,• ,
• • •
/ 1‘. " $ I • • •
•• I •
T-79-5
".N our, ona. alma
Sp 83.1 %.:74. "t T•• 67.4*
• 1 s -• • % /
I I ...• • # ga.
" / I
• % %
•••
•••
% 1 / / 1 ' 0 lc 1 1 *
• / a%/1%
t -400
, • %,
Effi > 70% HEMO.ILMENITE
30-70 % 1.150:0-ILMENITE
MontdoSITE
LAKES
• STRIKE: SECTIONI OF
LAC TIO ILMENITE DTEPOSiT
scALE: Çaoo
11111111MMEMENIIMINIBMEWRIONEM
K !•S
o 0 o
7 Lboo
LEGEND
Percent Cr201 in hemo-ilmenite concentrates of 7eolcwica1 Lection JK.
'1AC PUYJALON
94- ,-
/ $7 — 60 ',•• -•.'s
• tZ-7-II WJre,..,4
Ir. '
O••./ ‘41-%•%-•;1.. •••‘/.."-•-;
„..1,1•1 :„‘• %••• • -‘0‘ e•:1•••:•;"- iN' ""' •
• e !.-,"•.•)%'•- • iv•Vi s',700 C•• • f••• ••• • Ci> 1, - '
e " • 'g
'.1•••‘‘' ‘f••7'--‘1•/'4‘.../ ..1.•17'..7"si•.:1•••11".
\%/"../ \**%, il -..‘"•'/'*) s' :r• "••%
, •••• - /rkt4••t`t tt,"(::'/srttf \-V;
-" ''-v•i.11/-*,1-/is,‘,•."\--r.";••„;••1 e v;.•:-;;;••0'.\-7/":/-v.•
I:.
CARTE GEOLOGIQUE DE LA REGION DU LAC ALLARD, COMTE DE SAGUENAY, QUEBEC (HARGRAVES, 19(32).
0 1 2 3 Km 1111 -3111111111---imm---J
0 1 2 MI. rauffinc--7111111Er
8 •
• • .
52 •..1 ,
Strike and dip of foliation
Strike and dip of contacts
Inferred fault
Railroad
Cents:10s, known or inferred
Anorthosite
Oxide-rich norite
Pyroxene syenite elneiss
Massive ilmenites
Direction et pendage de la foliation
Direction et pendage des contacts
Faille supposée
Voie ferrée
Contacts, connus ou supposés
Anorthosite
Norite riche en oxide
Gneiss sye'nitique à pyroxène
440 gmenite mussive
1•1.1.1••••••••••••••••=1.
GEOLOGICAL MAP OF THE ALLARD LAKE AREA, SAGUENAY COUNTY, QUEBEC (HARGRAVES, 1962).
"1.