I B T I M B A R I Aley carbonatite, British Columbia, Canada D.A.R....
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Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral exploration: Aley carbonatite, British Columbia, Canada 1 1, 2 3 2 3 3 3 4 D.A.R. Mackay , G.J. Simandl , B. Grcic , P. Luck , C. Li , W. Ma , M. Redfearn , and J. Gravel 1 University of Victoria, School of Earth and Ocean Sciences, Victoria, BC 2 British Columbia Ministry of Energy and Mines, Victoria, BC 3 Bureau Veritas Canada Ltd., Inspectorate Metallurgical Division, Richmond, BC 4 Bureau Veritas Canada Ltd., Upstream Minerals Group, Vancouver, BC Also available as British Columbia Geological Survey Geofile 2015-07 Mackay, D.A.R., Simandl, G.J., Grcic, B., Luck, P., Li, C, Ma, W., Redfearn, M., and Gravel, J. 2015. Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral exploration: Aley carbonatite, British Columbia, Canada. British Columbia Ministry of Energy and Mines, British Columbia Geological Survey, Geofile 2015-07. Ore Systems TG 4 Natural Resources Canada Ressources naturelles Canada University of Victoria Ministry of Energy and Mines G Y E E O V L R O U G S I C A L C O L H U S M I T B I I R A B Conclusions - Mozley C800 Laboratory Mineral Separator is a compact, simple instrument with operating conditions that can be optimized for drainage-, deposit-, or commodity-specific conditions. - Mozley C800 increased concentrations of Nb (average factor of 4.3), Ta (average factor of 3.1), and LREE (average factor of 3.1) from stream-sediment samples. - Pyrochlore, columbite-Fe, monazite and REE-bearing fluorocarbonates were consistently concentrated. - Based on chemical analyses, a predictable relationship between indicator mineral counts in raw stream-sediment samples and concentrates should be expected. - These findings justify stage 3 of this project which involves microscopic, SEM (QEMSCAN), and electron microprobe methodology to reduce or eliminate the need for hand- picking indicator minerals. The Aley Carbonatite (290 km north of Prince George, BC; inset map) outcrops over a 3-3.5 km diameter area. Measured+indicated resources are 286 million tonnes at 0.37% Nb O (Taseko Mines Limited, 2013). The Aley Carbonatite 2 5 intruded into platformal carbonate and siliciclastic rocks of the Kechika Formation, Skoki Formation and Road River Group. Twelve stream-sediment samples (locations denoted by red circles) were collected from the stream draining the Aley carbonatite. ; modified after Mäder (1986), Massey et al. From Mackay et al. 2015 (2005), McLeish (2013) and Mackay and Simandl (2014). ( ) A sample being poured Left onto a Mozley C800. Water is supplied to the v-profile tray by the wash water pipe and the irrigation pipes. Arrows denote the direction of water flow. Duration of processing varied during operating condition optimization to suit deposit characteristics and sample size. Other operating parameters were kept constant for all samples. From Mackay et al. 2015. ( ) Separated concentrate Below (high density), middlings (medium density), and tailings (low density). Concentrate narrows to where the middlings start. Separation of middlings from tailings is marked by a decrease in the spatial density of grains. From Mackay et al. 2015. Synthetic standards (75g) were used to test operating parameters. They were made predominantly of quartz with 0.33 to 10 wt. % each of magnetite, garnet, and fluorite. The excellent correlation 2 (R =0.98) between magnetite in synthetic standards and in Mozley C800 concentrates indicates consistent concentration. Magnetite concentration increased by 5.5 to 228.2 times. From Mackay et al. 2015. ( ) Excellent correlation, based on high coefficients of determination Above 2 2 2 2 (R ), of ) Nb (R =0.94), ) LREE (R =0.80), Fe (R =0.86) and moderate ( ( a b 2 correlation of ) Y (R =0.77) in raw samples and Mozley C800 (c concentrates indicates consistent and effective concentration of pyrochlore, columbite-(Fe), magnetite, monazite, and REE- 2 fluorcarbonates. The low coefficient of determination ( R =0.23) d; between Ta concentrations in raw samples and Mozley C800 concentrates is likely due to concentrations near the detection limit. From Mackay et al. 2015. The proportion of concentrate for five identical sub-samples (~75g) of AL-13-16 decreased with increasing processing time. All other parameters were kept constant. The 15 minute time interval was selected for the remaining samples; this time is a compromise which ensures adequate concentration of heavy minerals, minimizing loss to tailings. From Mackay et al. 2015. Acknowledgements: This project received funding and support from Targeted Geoscience Initiative 4 (2010-2015), a Natural Resources Canada program carried out under the auspices of the Geological Survey of Canada. Inspectorate Exploration & Mining Services Ltd. and ACME Analytical Laboratories are thanked for their generous support of this project. Logistical and helicopter support by Taseko Mines Limited and the scholarship from Geoscience BC to the first author are also greatly appreciated. Pearce Luck (British Columbia Geological Survey) and Cheng Li (Bureau Veritas Canada Ltd., Inspectorate Metallurgical Division) are thanked for their assistance and expertise during laboratory work. References: Mackay, D.A.R. and Simandl, G.J. 2014. Portable X-ray fl uorescence to optimize stream sediment chemistry and indicator mineral surveys, case 1: Carbonatite-hosted Nb deposits, Aley carbonatite, British Columbia, Canada; In: Geological Fieldwork 2013, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2014-1, pp. 183-194. Mackay, D.A.R., Simandl, G.J., Grcic, B., Li, C., Luck, P., Redfearn, M. and Gravel, J., 2015. Evaluation of Mozley C800 laboratory mineral separator for heavy mineral concentration of stream sediments in exploration for carbonatite- related specialty metal deposits: case study at the Aley carbonatite, British Columbia (NTS 094B); In: Geoscience BC Summary of Activities 2014, Geoscience BC, Report 2015-1, p. 111-122. Mäder, U. K., 1986. The Aley Carbonatite Complex. Master of Science thesis, University of British Columbia, 176 p. Massey, J.W.H., McIntyre, D.G., Dejardins, P.J., and Cooney, R.T., 2005. Digital geology map of British Columbia. British Columbia Ministry of Energy, Mines and Petroleum Resources, British Columbia Geological Survey Open File 2005-2, DVD. McLeish, D.F., 2013. Structure, stratigraphy, and U-Pb ziron-titanite geochronology of the Aley carbonatite complex, Northeast British Columbia: Evidence for Antler-aged orogenesis in the foreland belt of the Canadian cordillera. Master of Science thesis, University of Victoria, 131 p. Study Area, Local Geology, and Stream Sediment Sample Locations Project Outline Concentration of potential carbonatite pathfinder elements for each size fraction of stream-sediment samples from the Aley area. The 125-250μm size fraction was selected for stage 2 and 3 geochemical and indicator mineral studies based on the distribution of material in the different size fractions and elemental concentrations (Nb, Ta, and LREE; La, Ce, Pr, Nd). Time permitting, the 63-125μm and 250-500μm size fractions would also be worthwhile for testing. From Mackay et al. 2015; modified from Mackay and Simandl 2014. Potential Indicator Minerals ( ) Mozley C800 heavy Left mineral concentrate (sample AL- 13-16) containing apatite (Ap), pyrochlore (Pcl), columbite-(Fe) (Cmb), and magnetite (Mag). Lithic fragments (Lit), and grain aggregates (Agg) are also present. Pyrochlore is identified by its distinctive octahedral crystal habit. Optical identification can be difficult in highly weathered grains. A magnet can be used to separate magnetite from columbite-(Fe) and other non-magnetic minerals. Limited exploration budgets and deposit andcommodity specific exploration necessitates a more focussed, customized approach. Stage 1 (previous work) involved characterising the Aley carbonatite, stream-sediment sample collection, and orientation survey. This involved chemical analyses of the sediments and selection of an optimal size fraction for indicator mineral studies (Luck and Simandl 2014; Mackay and Simandl 2014). Stage 2 ( ) involves evaluation of inexpensive and current study rapid methods to produce heavy-mineral concentrates for specialty metal-targeted exploration. An initial assessment of the Mozley C800 Laboratory Mineral Separator (referred to from here on as Mozley C800) is presented using synthetic standards (prepared for this purpose) and stream-sediments collected from the Aley carbonatite drainage area. Minerals with high densities and constituent Nb, Ta, and light rare earth elements (LREE; La, Ce, Pr, and Nd) were selected as potential indicator mineral candidates. Stage 3 (proceeding concurrently with stage 2) will address customization of microscopic, SEM, QEMSCAN, and electron microprobe methods in advanced mineralogical studies. ( ) Most stream-sediment samples (~75g) show 24.7-32.0% of Above material retained in concentrate, consistent with the natural sample used during optimization. Sample AL-13-09 (sampled upstream of the carbonatite) shows noticeably lower proportions of retained concentrate (3.8%). ( ) Mozley C800 concentrates show large average increases Below in the concentration of Nb (4.3 times), Ta (3.1 times), and LREE (3.1 times) relative to raw (unprocessed) samples. Samples are ordered by their geographic location from west to east (see map). The decreasing carbonatite signature with increasing distance downstream is preserved. From Mackay et al. 2015. Main Objectives: - To refine customized indicator mineral and geochemical methodologies to explore for poorly exposed specialty metal deposits in the Canadian Cordillera. - Assess heavy mineral separation by Mozley C800 Laboratory Mineral Separator with an emphasis on recovering Nb-bearing (pyrochlore and columbite-[Fe]) and rare earth element (REE)-bearing (monazite and REE-fluorocarbonates) minerals. - Evaluate the advantages of automated methods (QEMSCAN) over hand picking for advanced mineralogical studies. - The results of this study will form the basis to optimize indicator mineral methodologies to explore for carbonatite-hosted specialty metal deposits world-wide. Processing Procedure Stream Sediment Orientation Survey Optimization of Operating Conditions Results and Discussion a) Euhedral columbite- (Fe) partially surrounded by apatite (polished grain mount in plane polarized light; ppl). The b) columbite-(Fe) grain shows irregular texture characteristic for the Aley carbonatite (back scatter electron; BSE). Composite grains containing two or more mineral phases are common. c) Euhedral pyrochlore grain (ppl). The d) pyrochlore is highly fractured and contains dolomite (Dol) and minor monazite (Mnz) inclusions (BSE). The grain also has a minor weathered rim of Nb and Fe oxide material. e) An anhedral apatite grain (ppl image) with f) subhedral pyrochlore and hematite inclusions. The apatite has an alteration (weathered) rim of hematite (Hem), magnetite and minor chlorite (Cl) (BSE). a) Fresh (unweathered) euhedral, dark brown and b) subhedral, strongly weathered pyrochlore grains from stream sediments sampled directly over the deposit (sample AL-13-04). c) Subhedral, slightly weathered and strongly weathered d) pyrochlore grains from downstream (8.8km; sample AL- 13-16) of the Aley carbonatite. 3 3 Potential indicator minerals for carbonatite-hosted specialty metal desposits include pyrochlore (4.20-6.40 g/cm ), columbite-(Fe) (5.30-7.30 g/cm ), fersmite (4.69-4.79 3 3 3 3 g/cm ), monazite (4.80-5.50 g/cm ) and REE-fluorocarbonates such as bastnaesite (4.95-5.00 g/cm ) and synchysite (3.90-4.15 g/cm ). These minerals have similar or 3 higher densities than magnetite (5.10-5.20 g/cm ) in the synthetic standards used for initial optimization of Mozley C800 operating conditions. AL-13-01 AL-13-01 AL-13-01 AL-13-04 AL-13-04 AL-13-04 AL-13-05 AL-13-05 AL-13-05 AL-13-06 AL-13-06 AL-13-06 AL-13-07 AL-13-07 AL-13-07 AL-13-08 AL-13-08 AL-13-08 AL-13-09 AL-13-09 AL-13-09 AL-13-16 AL-13-16 AL-13-16 AL-13-18 AL-13-18 AL-13-18B AL-13-18B AL-13-18 AL-13-18B AL-13-10 AL-13-10 AL-13-10 AL-13-02 AL-13-02 AL-13-02 Lithological Contact River Normal Fault Thrust Fault Stream Sediment Samples Elevation Contour ORI ORI ORI Osk Osk Osk CmOK CmOK CmOK Lower to Upper Ordovician-Silurian Road River Group. Cherty dolostone, shale, argillaceous limestone, and rare quartzite and quartz pebble conglomerate Cambiran-Ordovician Kechika Formation. argillaceous limestone, calcareous siltstone, and dolostone. Aley Carbonatite Lower to Middle Ordovician Skoki Formation. Dolomite carbonate rocks. Massive Carbonatite Related Fenitization Ospika Diatreme REE-Bearing Carbonatite Dykes 6256000 6256000 6256000 6258000 6258000 6258000 455000 455000 455000 453000 453000 453000 451000 451000 451000 449000 449000 449000 447000 447000 447000 Aley Carbonatite and Intrusive Rocks Cambrian and Ordovician Al Creek Al Creek Al Creek 6254000 6254000 6254000 6252000 6252000 6252000 ORI ORI ORI ORI ORI ORI ORI ORI ORI Osk Osk Osk Osk Osk Osk CmOK CmOK CmOK CmOK CmOK CmOK CmOK CmOK CmOK Osk Osk Osk Osk Osk Osk CmOK CmOK CmOK ORI ORI ORI Ospika Diatreme Ospika Diatreme Ospika Diatreme Aley Carbonatite Aley Carbonatite Aley Carbonatite Ordovician and Silurian Ordovician British Columbia Yukon Northwest Territories Alberta USA Alaska Kamloops Vancouver Prince George Pacific Ocean Aley Carbonatite Complex 0 400 km 0 5000 10000 0 125 250 0 1000 2000 0 1000 2000 3000 0 250 500 750 0 500 1000 0 500 1000 1500 0 250 500 750 0 100 200 0 5000 10000 0 50 100 0 25 Sieve Opening Size 0 500 1000 1500 Nb (ppm) Ta (ppm) Y (ppm) La (ppm) Ce (ppm) Pr (ppm) Nd (ppm) Ba (ppm) Sr (ppm) P (ppm) U (ppm) Th (ppm) Size Fraction (wt. %) >4mm 2-4mm 1-2mm 500μm-1mm 250-500μm 125-250μm 63-125μm <63μm Sieve Opening Size >4mm 2-4mm 1-2mm 500μm-1mm 250-500μm 125-250μm 63-125μm <63μm AL-13-02 AL-13-18 Tailings Tailings Tailings Middlings Middlings Middlings Concentrate Concentrate Concentrate Water flow Water flow Water flow Water flow Water flow Water flow Irrigation Pipes Irrigation Pipes Irrigation Pipes Wash Water Pipe Wash Water Pipe Wash Water Pipe Starting Mass of Magnetite in Synthtic Standards (g) Mass of Magnetite in Mozley C800 Concentrates (g) Duration of processing by Mozley C800 (min) Proportion of material retained Tailings Middlings Concentrate Sample number Proporon of material retained Tailings Middlings Concentrate Nb (ppm) 0 50 100 150 200 250 300 350 Ta (ppm) LREE ( ΣLa, Ce, Pr, Nd) (ppm) Sample ID 15000 20000 25000 10000 5000 0 Tailings Raw Concentrate R² = 0.94 0 2000 4000 6000 8000 10000 12000 0 5000 10000 15000 20000 25000 30000 Nb in Concentrate (ppm) Nb in Raw Samples (ppm) a AL-13-16 AL-13-18 AL-13-18B AL-13-01 AL-13-10 AL-13-09 AL-13-05 AL-13-07 AL-13-08 AL-13-04 AL-13-02 AL-13-06 R² = 0.23 0 20 40 60 80 100 120 140 160 180 0 50 100 150 200 250 300 350 400 Ta in Concentrate (ppm) Ta in Raw Samples (ppm) d AL-13-16 AL-13-18 AL-13-18B AL-13-01 AL-13-10 AL-13-09 AL-13-05 AL-13-07 AL-13-08 AL-13-04 AL-13-02 AL-13-06 R² = 0.77 0 20 40 60 80 100 120 140 160 180 200 0 50 100 150 200 250 300 350 400 Y in Concentrate (ppm) Y in Raw Samples (ppm) c AL-13-16 AL-13-18 AL-13-18B AL-13-01 AL-13-10 AL-13-09 AL-13-05 AL-13-07 AL-13-08 AL-13-04 AL-13-02 AL-13-06 LREE (Σ La, Ce, Pr, Nd) in Concentrate (ppm) LREE (Σ La, Ce, Pr, Nd) in Raw Samples (ppm) b R² = 0.80 0 2000 3000 4000 5000 6000 7000 8000 9000 0 5000 10000 15000 20000 25000 1000 AL-13-16 AL-13-18 AL-13-18B AL-13-01 AL-13-10 AL-13-09 AL-13-05 AL-13-07 AL-13-08 AL-13-04 AL-13-02 AL-13-06 Pcl Pcl Pcl Cmb Cmb Cmb Mag Mag Mag Mag Mag Mag Ap Ap Ap 0.5 mm 0.5 mm 0.5 mm Agg Agg Agg Lit Lit Lit Pcl Pcl Pcl Dol Dol Dol Ap Ap Ap Pcl Pcl Pcl Hem Hem Hem Ap Ap Ap Cmb Cmb Cmb 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm 100μm a a b b c c d d e e f f Mnz Mnz Mnz Rim Rim Rim Mag Mag Mag Cl Cl Cl 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm 0.25 mm a a b b d d c c 0.25 mm 0.25 mm 0.25 mm
Transcript of I B T I M B A R I Aley carbonatite, British Columbia, Canada D.A.R....
Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral exploration: Aley carbonatite, British Columbia, Canada
1 1, 2 3 2 3 3 3 4D.A.R. Mackay , G.J. Simandl , B. Grcic , P. Luck , C. Li , W. Ma , M. Redfearn , and J. Gravel
1University of Victoria, School of Earth and Ocean Sciences, Victoria, BC
2British Columbia Ministry of Energy and Mines, Victoria, BC
3Bureau Veritas Canada Ltd., Inspectorate Metallurgical Division, Richmond, BC
4Bureau Veritas Canada Ltd., Upstream Minerals Group, Vancouver, BC
Also available as British Columbia Geological Survey Geofile 2015-07Mackay, D.A.R., Simandl, G.J., Grcic, B., Luck, P., Li, C, Ma, W., Redfearn, M., and Gravel, J. 2015. Assessment of Mozley C800 laboratory mineral separator for specialty metal indicator mineral exploration: Aley carbonatite, British Columbia, Canada. British Columbia Ministry of Energy and Mines, British Columbia Geological Survey, Geofile 2015-07.
Ore SystemsTG
4Natural ResourcesCanadaRessources naturellesCanada
Universityof VictoriaMinistry of
Energy and Mines
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COLH US MIT BI IR A
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Conclusions
- Mozley C800 Laboratory Mineral Separator is a compact, simple instrument with operating conditions that can be optimized for drainage-, deposit-, or commodity-specific conditions.
- Mozley C800 increased concentrations of Nb (average factor of 4.3), Ta (average factor of 3.1), and LREE (average factor of 3.1) from stream-sediment samples.
- Pyrochlore, columbite-Fe, monazite and REE-bearing fluorocarbonates were consistently concentrated.
- Based on chemical analyses, a predictable relationship between indicator mineral counts in raw stream-sediment samples and concentrates should be expected.
- These findings justify stage 3 of this project which involves microscopic, SEM (QEMSCAN), and electron microprobe methodology to reduce or eliminate the need for hand-picking indicator minerals.
The Aley Carbonatite (290 km north of Prince George, BC; inset map) outcrops over a 3-3.5 km diameter area. Measured+indicated resources are 286 million tonnes at 0.37% Nb O (Taseko Mines Limited, 2013). The Aley Carbonatite 2 5
intruded into platformal carbonate and siliciclastic rocks of the Kechika Formation, Skoki Formation and Road River Group. Twelve stream-sediment samples (locations denoted by red circles) were collected from the stream draining the Aley carbonatite. ; modified after Mäder (1986), Massey et al. From Mackay et al. 2015(2005), McLeish (2013) and Mackay and Simandl (2014).
( ) A sample being poured Leftonto a Mozley C800. Water is supplied to the v-profile tray by the wash water pipe and the irrigation pipes. Arrows denote the direction of water flow. Duration of processing varied during operating condition optimization to suit deposit characteristics and sample size. Other operating parameters were kept constant for all samples. From Mackay et al. 2015.( ) Separated concentrate Below(high density), middl ings (medium density), and tailings (low density). Concentrate narrows to where the middlings start. Separation of middlings from tailings is marked by a decrease in the spatial density of grains. From Mackay et al. 2015.
Synthetic standards (75g) w e r e u s e d t o t e s t operating parameters. T h e y w e r e m a d e predominantly of quartz with 0.33 to 10 wt. % each o f magnet i te , garnet, and fluorite. The excel lent correlat ion
2( R = 0 . 9 8 ) b e t w e e n magnetite in synthetic standards and in Mozley C 8 0 0 c o n c e n t r a t e s indicates consistent concentration. Magnetite concentration increased by 5.5 to 228.2 times. From Mackay et al. 2015.
( ) Excellent correlation, based on high coefficients of determination Above2 2 2 2(R ), of ) Nb (R =0.94), ) LREE (R =0.80), Fe (R =0.86) and moderate ( (a b
2correlation of ) Y (R =0.77) in raw samples and Mozley C800 (cconcentrates indicates consistent and effective concentration of pyrochlore, columbite-(Fe), magnetite, monazite, and REE-
2fluorcarbonates. The low coefficient of determination ( R =0.23) d; between Ta concentrations in raw samples and Mozley C800 concentrates is likely due to concentrations near the detection limit. From Mackay et al. 2015.
T h e p r o p o r t i o n o f concentrate for f ive identical sub-samples (~75g) o f AL-13-16 d e c r e a s e d w i t h increasing processing time. All other parameters were kept constant. The 15 minute time interval was selected for the remaining samples; this time is a compromise which ensures adequate concentration of heavy minerals, minimizing loss to tailings. From Mackay et al. 2015.
Acknowledgements:This project received funding and support from Targeted Geoscience Initiative 4 (2010-2015), a Natural Resources Canada program carried out under the auspices of the Geological Survey of Canada. Inspectorate Exploration & Mining Services Ltd. and ACME Analytical Laboratories are thanked for their generous support of this project. Logistical and helicopter support by Taseko Mines Limited and the scholarship from Geoscience BC to the first author are also greatly appreciated. Pearce Luck (British Columbia Geological Survey) and Cheng Li (Bureau Veritas Canada Ltd., Inspectorate Metallurgical Division) are thanked for their assistance and expertise during laboratory work.
References:
Mackay, D.A.R. and Simandl, G.J. 2014. Portable X-ray fl uorescence to optimize stream sediment chemistry and
indicator mineral surveys, case 1: Carbonatite-hosted Nb deposits, Aley carbonatite, British Columbia, Canada; In:
Geological Fieldwork 2013, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey
Paper 2014-1, pp. 183-194.
Mackay, D.A.R., Simandl, G.J., Grcic, B., Li, C., Luck, P., Redfearn, M. and Gravel, J., 2015. Evaluation of Mozley C800
laboratory mineral separator for heavy mineral concentration of stream sediments in exploration for carbonatite-
related specialty metal deposits: case study at the Aley carbonatite, British Columbia (NTS 094B); In: Geoscience
BC Summary of Activities 2014, Geoscience BC, Report 2015-1, p. 111-122.
Mäder, U. K., 1986. The Aley Carbonatite Complex. Master of Science thesis, University of British Columbia, 176 p.
Massey, J.W.H., McIntyre, D.G., Dejardins, P.J., and Cooney, R.T., 2005. Digital geology map of British Columbia. British
Columbia Ministry of Energy, Mines and Petroleum Resources, British Columbia Geological Survey Open File
2005-2, DVD.
McLeish, D.F., 2013. Structure, stratigraphy, and U-Pb ziron-titanite geochronology of the Aley carbonatite complex,
Northeast British Columbia: Evidence for Antler-aged orogenesis in the foreland belt of the Canadian cordillera.
Master of Science thesis, University of Victoria, 131 p.
Study Area, Local Geology, and Stream Sediment Sample Locations
Project Outline
Concentration of potential carbonat i te pathf inder elements for each size fraction of stream-sediment samples from the Aley area. The 125 -250μm s i ze fraction was selected for stage 2 and 3 geochemical and indicator mineral studies based on the distribution of material in the different size fractions and elemental concentrations (Nb, Ta, and LREE; La, Ce, Pr, Nd). Time permitting, the 63-125μm and 250-500μm size fractions would also be worthwhile for testing. From Mackay e t a l . 2015 ; modified from Mackay and Simandl 2014.
Potential Indicator Minerals
( ) Mozley C800 heavy Leftmineral concentrate (sample AL-13-16) containing apatite (Ap), pyrochlore (Pcl), columbite-(Fe) (Cmb), and magnetite (Mag). Lithic fragments (Lit), and grain aggregates (Agg) are also present. Pyrochlore is identified by its distinctive octahedral c r y s t a l h a b i t . O p t i c a l identification can be difficult in highly weathered grains. A magnet can be used to separate magnetite from columbite-(Fe) a n d o t h e r n o n - m a g n e t i c minerals.
Limited exploration budgets and deposit andcommodity specific exploration necessitates a more focussed, customized approach.
Stage 1 (previous work) involved characterising the Aley carbonatite, stream-sediment sample collection, and orientation survey. This involved chemical analyses of the sediments and selection of an optimal size fraction for indicator mineral studies (Luck and Simandl 2014; Mackay and Simandl 2014).
Stage 2 ( ) involves evaluation of inexpensive and current studyrapid methods to produce heavy-mineral concentrates for specialty metal-targeted exploration. An initial assessment of the Mozley C800 Laboratory Mineral Separator (referred to from here on as Mozley C800) is presented using synthetic standards (prepared for this purpose) and stream-sediments collected from the Aley carbonatite drainage area. Minerals with high densities and constituent Nb, Ta, and light rare earth elements (LREE; La, Ce, Pr, and Nd) were selected as potential indicator mineral candidates.
Stage 3 (proceeding concurrently with stage 2) will address customization of microscopic, SEM, QEMSCAN, and electron microprobe methods in advanced mineralogical studies.
( ) Most stream-sediment samples (~75g) show 24.7-32.0% of Abovematerial retained in concentrate, consistent with the natural sample used during optimization. Sample AL-13-09 (sampled upstream of the carbonatite) shows noticeably lower proportions of retained concentrate (3.8%). ( ) Mozley C800 concentrates show large average increases Belowin the concentration of Nb (4.3 times), Ta (3.1 times), and LREE (3.1 times) relative to raw (unprocessed) samples. Samples are ordered by their geographic location from west to east (see map). The decreasing carbonatite signature with increasing distance downstream is preserved. From Mackay et al. 2015.
Main Objectives:
- To refine customized indicator mineral and geochemical methodologies to explore for poorly exposed specialty metal deposits in the Canadian Cordillera.
- Assess heavy mineral separation by Mozley C800 Laboratory Mineral Separator with an emphasis on recovering Nb-bearing (pyrochlore and columbite-[Fe]) and rare earth element (REE)-bearing (monazite and REE-fluorocarbonates) minerals.
- Evaluate the advantages of automated methods (QEMSCAN) over hand picking for advanced mineralogical studies.
- The results of this study will form the basis to optimize indicator mineral methodologies to explore for carbonatite-hosted specialty metal deposits world-wide.
Processing ProcedureStream Sediment Orientation Survey
Optimization of Operating Conditions
Results and Discussion
a) Euhedral columbite-(Fe) partially surrounded by apatite (polished grain mount in plane polarized l igh t ; pp l ) . The b)columbite-(Fe) grain shows irregular texture characteristic for the Aley carbonatite (back scatter e l e c t r o n ; B S E ) . C o m p o s i t e g r a i n s containing two or more mineral phases are common. c) Euhedral pyrochlore grain (ppl). The d)pyrochlore is highly fractured and contains dolomite (Dol) and minor m o n a z i t e ( M n z ) inclusions (BSE). The grain also has a minor weathered rim of Nb and Fe oxide material.e) An anhedral apatite grain (ppl image) with f)subhedral pyrochlore and hematite inclusions. The apatite has an alteration (weathered) rim of hematite (Hem), magnetite and minor chlorite (Cl) (BSE).
a ) F r e s h ( u n w e a t h e r e d ) euhedral, dark brown and b)subhedral, strongly weathered pyrochlore grains from stream sediments sampled directly over the deposit (sample AL-13-04). c)Subhedral, slightly weathered and strongly weathered d) p y r o c h l o r e g r a i n s f r o m downstream (8.8km; sample AL-13-16) of the Aley carbonatite.
3 3Potential indicator minerals for carbonatite-hosted specialty metal desposits include pyrochlore (4.20-6.40 g/cm ), columbite-(Fe) (5.30-7.30 g/cm ), fersmite (4.69-4.79 3 3 3 3g/cm ), monazite (4.80-5.50 g/cm ) and REE-fluorocarbonates such as bastnaesite (4.95-5.00 g/cm ) and synchysite (3.90-4.15 g/cm ). These minerals have similar or
3higher densities than magnetite (5.10-5.20 g/cm ) in the synthetic standards used for initial optimization of Mozley C800 operating conditions.
AL-13-01AL-13-01AL-13-01
AL-13-04AL-13-04AL-13-04AL-13-05AL-13-05AL-13-05
AL-13-06AL-13-06AL-13-06AL-13-07AL-13-07AL-13-07
AL-13-08AL-13-08AL-13-08
AL-13-09AL-13-09AL-13-09
AL-13-16AL-13-16AL-13-16
AL-13-18AL-13-18AL-13-18BAL-13-18BAL-13-18AL-13-18B
AL-13-10AL-13-10AL-13-10
AL-13-02AL-13-02AL-13-02
Lithological Contact
River
Normal Fault
Thrust Fault
Stream Sediment Samples
Elevation Contour
ORIORIORI
OskOskOsk
CmOKCmOKCmOK
Lower to Upper Ordovician-Silurian Road River Group. Cherty dolostone, shale, argillaceous limestone, and rare quartzite and quartz pebble conglomerate
Cambiran-Ordovician Kechika Formation. argillaceous limestone, calcareous siltstone, and dolostone.
Aley Carbonatite
Lower to Middle Ordovician Skoki Formation. Dolomite carbonate rocks.
Massive Carbonatite Related Fenitization
Ospika Diatreme
REE-Bearing Carbonatite Dykes
625600062560006256000
625800062580006258000
455000
455000
455000
453000
453000
453000
451000
451000
451000
449000
449000
449000
447000
447000
447000
Aley Carbonatite and Intrusive Rocks
Cambrian and Ordovician
Al CreekAl CreekAl Creek
625400062540006254000
625200062520006252000
ORIORIORI
ORIORIORI
ORIORIORI
OskOskOsk
OskOskOskCmOKCmOKCmOK
CmOKCmOKCmOK
CmOKCmOKCmOK
OskOskOsk
OskOskOskCmOKCmOKCmOK
ORIORIORI
Ospika DiatremeOspika DiatremeOspika Diatreme
Aley CarbonatiteAley CarbonatiteAley Carbonatite
Ordovician and Silurian
OrdovicianBritish
Columbia
Yukon Northwest Territories
Alberta
USA
Alaska
Kamloops
Vancouver
Prince George
Pacific Ocean
Aley CarbonatiteComplex
0 400km
0
5000
10000
0
125
250
0
1000
2000
0
1000
2000
3000
0
250
500
750
0
500
1000
0500
10001500
0
250
500
750
0
100
200
0
5000
10000
0
50
100
0
25
Sieve Opening Size
0
500
1000
1500
Nb
(p
pm
)Ta
(p
pm
)Y
(pp
m)
La (
pp
m)
Ce
(pp
m)
Pr
(pp
m)
Nd
(p
pm
)B
a (p
pm
)Sr
(p
pm
)P
(p
pm
)U
(p
pm
)Th
(p
pm
)Si
ze F
ract
ion
(wt.
%)
>4mm
2-4m
m
1-2m
m
500μm
-1m
m
250-500μ
m
125-250μ
m
63-125μ
m
<63μm
Sieve Opening Size
>4mm
2-4m
m
1-2m
m
500μm
-1m
m
250-500μ
m
125-250μ
m
63-125μ
m
<63μm
AL-13-02 AL-13-18
TailingsTailingsTailings MiddlingsMiddlingsMiddlings ConcentrateConcentrateConcentrate
Water flowWater flowWater flow
Wate
r flo
wW
ate
r flo
wW
ate
r flo
w
Irrigatio
n P
ipes
Irrigatio
n P
ipes
Irrigatio
n P
ipes
Wash Water PipeWash Water PipeWash Water Pipe
Sta
rtin
g M
ass o
f M
ag
neti
te in
Syn
thti
c S
tan
dard
s (
g)
Mass of Magnetite in Mozley C800 Concentrates (g)
Duration of processing by Mozley C800 (min)
Pro
po
rtio
n o
f m
ate
rial re
tain
ed
Tailings
Middlings
Concentrate
Sample number
Prop
or�
on o
f m
ater
ial r
etai
ned
Tailings
Middlings
Concentrate
Nb
(p
pm
)
0
50
100
150
200
250
300
350
Ta (
pp
m)
LREE
(ΣLa
, Ce,
Pr,
Nd
) (p
pm
)
Sample ID
15000
20000
25000
10000
5000
0
Tailings
Raw
Concentrate
R² = 0.94
0
2000
4000
6000
8000
10000
12000
0 5000 10000 15000 20000 25000 30000
Nb in Concentrate (ppm)
Nb
in R
aw S
amp
les
(pp
m)
aa
AL-13-16
AL-13-18
AL-13-18B AL-13-01
AL-13-10
AL-13-09
AL-13-05
AL-13-07
AL-13-08
AL-13-04
AL-13-02
AL-13-06
R² = 0.23
0
20
40
60
80
100
120
140
160
180
0 50 100 150 200 250 300 350 400
Ta in Concentrate (ppm)
Ta in
Raw
Sam
ple
s (p
pm
)
d
AL-13-16
AL-13-18
AL-13-18B AL-13-01
AL-13-10
AL-13-09
AL-13-05
AL-13-07
AL-13-08AL-13-04 AL-13-02
AL-13-06
R² = 0.77
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200 250 300 350 400
Y in Concentrate (ppm)
Y in
Raw
Sam
ple
s (p
pm
)
c
AL-13-16
AL-13-18AL-13-18B
AL-13-01
AL-13-10
AL-13-09
AL-13-05
AL-13-07
AL-13-08
AL-13-04
AL-13-02
AL-13-06
LREE (Σ La, Ce, Pr, Nd) in Concentrate (ppm)
LRE
E (
Σ La
, Ce
, Pr,
Nd
) in
Raw
Sam
ple
s (p
pm
)
b
R² = 0.80
0
2000
3000
4000
5000
6000
7000
8000
9000
0 5000 10000 15000 20000 25000
1000
AL-13-16
AL-13-18
AL-13-18B
AL-13-01
AL-13-10
AL-13-09
AL-13-05
AL-13-07
AL-13-08
AL-13-04
AL-13-02AL-13-06
PclPclPcl
CmbCmbCmb
MagMagMag
MagMagMag
ApApAp
0.5 mm0.5 mm0.5 mm
AggAggAggLitLitLit
PclPclPcl
DolDolDol
ApApApPclPclPcl
HemHemHem
ApApApCmbCmbCmb
100μm100μm100μm
100μm100μm100μm
100μm100μm100μm
100μm100μm100μm
100μm100μm100μm
100μm100μm100μm
aaa bbb
ccc ddd
eee fff
MnzMnzMnz
RimRimRim
MagMagMagClClCl
0.25 mm0.25 mm0.25 mm
0.25 mm0.25 mm0.25 mm
0.25 mm0.25 mm0.25 mm
aaa bbb
dddccc
0.25 mm0.25 mm0.25 mm
