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Assessment of Mozley and Wilfley shaking tables for concentrating carbonatite indicator minerals, Aley carbonatite, British Columbia, Canada 1 1, 2 3 3 3 2 3 Duncan A.R. Mackay , George J. Simandl , Wendy Ma , Boja Grcic , Mike Redfearn , Pearce Luck , and Cheng Li 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 Commodities Canada Ltd., Inspectorate Metallurgical Division, Richmond, BC For further details please contact: [email protected] Ore Systems TG 4 Natural Resources Canada Ressources naturelles Canada University of Victoria Ministry of Energy and Mines Conclusions Mozley C800 laboratory mineral seperator Wilfley Shaking Table #13 Tailings Tailings Tailings Middlings Middlings Middlings Concentrate Concentrate Concentrate Water flow Water flow Water flow Figure 3. View of the surface of the Mozley C800 laboratory mineral separator table after a completed run. Sample material is separated into concentrate, middlings and tailings based on pattern and colour of the material stream. Once the selected time interval (15-minutes in this case) is reached, the table and water are turned off. The division of sediment into concentrate, middlings and tailings is visually discernable by shape and colour of the material stream (Figure 3). Tailings, middlings and concentrate are separated and washed into separate containers. Seperator Mozley C800 (Mackay et al. 2015a) Wilfley #13 (Mackay et al. 2015b) Dimensions (portability) Approx. 1.2m x 1m x 1m; pick-up truck transportable; designed to be moved (field or laboratory based) Approx. 2.0m x 0.75m x 1.25m; commonly a stationary set up (laboratory based; Level of training and operator attentiveness needed to operate High Moderate Use of synthetic standards for optimizing operating conditions Recommended Recommended Approximate water usage (based on optimized parameters) 1.6 L/min (15 min/sample) 24L/sample 18 L/min (approx. 5min/sample; dependant on sample size) 90L/sample Recommended sample size (based on manufacturer's specifications) 50-100g N/A; but 8.6-65.0 kg in 0.25-1mm size fraction of till samples have been used (example from McClenaghan 2011) Sample size successfully tested (125- 250 μm fraction) 75g (90-100g sample may be preferred for low indicator mineral counts) 380-940g Grain size (based on manufacturer's specifications) 100 μm - 2 mm (v-profile tray) <100 μm (flat tray) <2 mm Cleaning Short cleanup (5 min) Long cleanup (20 min) Risk of contamination Low; minimal material traps High; several potential material traps Processing time per sample 15 min; samples < 100g 5 min; samples < 1000g N/A = not available *Smaller and larger table sizes available on the market 475mm x 1016mm table size*) Table 4: Comparison of Mozley C800 Laboratory Mineral Separator and Wilfley Shaking Table #13 performance and applicability to Aley-style carbonatite-hosted Nb-deposits 0 10 20 30 40 50 60 70 80 90 100 Proportion (Wt.%) Tailings Middlings Concentrate Figure 4. Proportion (Wt.%) of concentrates, middlings, and tailings after Mozley processing (stream sediments from the Aley carbonatite drainage area). AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 Water flow Water flow Water flow Irrigation pipes Irrigation pipes Irrigation pipes Wash water pipe Wash water pipe Wash water pipe Figure 2. The operating procedure is simple once optimal conditions for sample processing are identified. Dry sieved (125–250 μm size fraction) samples weighing ~75 g are poured from a beaker onto the table and wetted at the wash water pipe (copper tube). A spray bottle is used to remove all material from the beaker. Water is supplied by the wash water pipe and the irrigation pipes (two white plastic tubes with water outlets at regular intervals). The direction of water flow is denoted by black arrows. Tailings separate first, moving longitudinally down the trough in the direction of water flow and are collected at the end of the table. The v-profile tray, best suited for coarse grain sizes (100 μm–2 mm), was used for this study. The Mozley C800 set up parameters were: 1.75° longitudinal slope; 70 rpm table speed; 6.35 cm amplitude (throw and stroke); and 1.6 L/min water flow rate. 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 Figure 1. Location and geology of the Aley carbonatite, British Columbia. Stream sediment sample locations are denoted by red circles. Modified after Pride (1983), Mäder (1986), Massey et al. (2005), McLeish (2013) and Mackay and Simandl (2014b). The Aley carbonatite is located 290 km north of Prince George, British Columbia (Figure 1), and outcrops over a 3 x 3.5 km area (Mäder, 1986; McLeish, 2013). It was selected as a case study location because it is the most important Nb-deposit in the Canadian Cordillera with a measured plus indicated resource of 286 million tonnes at 0.37% Nb O , with a cut-off grade of 0.20% Nb O (Jones 2 5 2 5 et al. 2014). It is hosted by greenschist facies metasediments. The main body of the Aley carbonatite is dolomitic with volumetrically minor calcite carbonatite, surrounded by fenitised country rock (Mäder, 1986; McLeish 2013). Sample feeder Sample feeder Sample feeder Launder trays Launder trays Launder trays Water source Water source Water source Direction of shaking Direction of shaking Direction of shaking Slope Slope Slope Incline Incline Incline Gear box Gear box Gear box Electric motor Electric motor Electric motor Figure 7. Dry sieved (125–250μm size fraction) stream sediment samples varying from 380- 940g were mixed into a slurry with water and gradually washed into the sample feeder (Figure 7). Material moves with the direction of shaking across the table surface and diagonally down the table slope. The table was set with an 8° incline, 3° slope, 10mm stroke, and table speed of 250 rpm for all samples from Aley. Water flow was kept constant for all samples at 18 L/min based on optimization using synthetic standards. Concentrate Concentrate Concentrate Middlings Middlings Middlings Tailings Tailings Tailings Figure 8. Close-up of the Wilfley table. Heavy minerals (black) are separated from middlings and tailings as material moves from the top-right to bottom-left. Denser material (concentrate) is carried farthest left along the table ridges while the least dense material is washed off the bottom of the table. Launder trays are positioned to collect the concentrate, middlings, and tailings. Suspended particles are allowed to settle and excess water is decanted from concentrates, middlings, and tailings. AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 0 20 40 60 80 100 Proportion (wt.%) Tailings Middlings Concentrate Figure 9. Proportion (Wt.%) of concentrates, middlings, and tailings after Wilfley table processing (stream sediments from the Aley carbonatite drainage area). 0 5000 10000 15000 30000 Nb content (ppm) 20000 25000 35000 Raw Concentrate (4.6) (3.9) (4.7) (5.6) (5.4) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 0 100 200 500 Ta content (ppm) 300 400 600 (3.5) (2.3) (3.3) (4.9) (4.0) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 0 5000 10000 25000 15000 20000 LREE (Σ La, Ce, Nd, Pr) content (ppm) (3.5) 0 (1.8) (4.5) (5.1) (4.5) Figure 10. Comparison of Nb, Ta, and LREE (Σ La, Ce, Nd, Pr) concentrations in Wilfley table concentrates and raw samples from Aley. Concentration factors (Wilfley concentrates /raw samples) are shown in parentheses. Raw Concentrate Raw Concentrate Comparison Objectives One of the main objectives of the Specialty Metals component of the Targeted Geoscience Initiative 4 (TGI-4) is to develop simple, inexpensive methods to explore for rare-earth element (REE) and niobium (Nb) ± tantalum (Ta) deposits described in Mackay and Simandl (2014a) and Simandl (2014). The main purpose of this study is to determine if Mozley and Wilfley tables can concentrate carbonatite indicator minerals (Table 1) to a degree that additional processing is not required for quantitative assessment using Quantitative Evaluation of Minerals by Scanning electron microscopy ® (QEMSCAN ). Expensive and labour intensive mineral picking is eliminated from indicator mineral surveys. 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. The specialty metal portion of the TGI-4 is carried out in collaboration with the British Columbia Geological Survey. Bureau Veritas Commodities Canada Ltd., Inspectorate Metallurgical Division and Upstream Minerals Sector 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. References: Jones, S., Merriam, K., Yelland, G., Rotzinger, R., and Simpson, R. G., 2014. Technical report on mineral reserves at the Aley project British Columbia, Canada. Taseko Mines Limited, National Instrument 43-101, 291p. Kressall, R., McLeish, D.F. and Crozier, J., 2010. The Aley carbonatite complex – Part II petrogenesis of a Cordilleran niobium deposit. In: Simandl, G.J., and Lefebure, D.V. (Eds.), International workshop on the geology of rare metals, November 9-10, 2010, Victoria, Canada. Extended Abstracts Volume. BC Ministry of Energy and Mines, British Columbia Geological Survey Open File 2010-10, pp. 25-26. Luck, P. and Simandl, G.J., 2014. Portable X-ray fluorescence in stream sediment chemistry and indicator mineral surveys, Lonnie Carbonatite Complex, British Columbia. In: Geological Fieldwork 2013, British Columbia Ministry of Energy and Mines, Paper 2014-1, p. 169-182. Mackay, D.A.R. and Simandl, G.J., 2014a. Geology, market and supply chain of niobium and tantalum–a review. Mineralium Deposita, 49, 1025-1047. Mackay, D.A.R., and Simandl, G.J., 2014b. Portable X-ray fluorescence 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, Paper 2014-1, p. 183-194. Mackay, D.A.R., Simandl, G.J., Luck, P., Grcic, B., Li, C., Redfearn, M., and Gravel, J., 2015a. Concentration of carbonatite indicator minerals using Wilfley gravity shaking table: A case history from the Aley carbonatite, British Columbia, Canada. In: Geological Fieldwork 2014, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-1, 189-195. Mackay, D.A.R., Simandl, G.J., Grcic, B., Li, C., Luck, P., Redfearn, M. and Gravel, J., 2015b. 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 and Mines, British Columbia Geological Survey, Open File 2005-2, DVD. McClenaghan, M.B., 2011. Overview of common processing methods for recovery of indicator minerals from sediments and bedrock in mineral exploration. Geochemistry: Exploration, Environment, Analysis, 11, 265-278. McLeish, D.F., 2013. Structure, stratigraphy, and U-Pb zircon-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. Pride, K.R., 1983. Geological survey on the Aley claims; British Columbia Ministry of Energy and Mines, Assessment Report 12018, 16 p. Simandl, G. J., 2014. Geology and market-dependent significance of rare earth element resources. Mineralium Deposita, 49, 889-904. The Mozley C800 (Figure 2) is a light and compact alternative to most other shaker tables and gravity concentrators used by metallurgists. It performs density sorting of grains using side to side (stroke) and front to back (throw) motions. During processing, material is separated into concentrate (high density), middlings (mixed), and tailings (low density). Information regarding the Mozley C800 concentrator presented here is derived from Mackay et al. (2015b). (3.6) (2.8) (3.1) (3.7) (3.3) 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Nb content ( ppm) Sample ID Concentrate Raw (2.3) (2.9) (2.5) (2.1) (2.3) 0 50 100 150 200 250 300 350 Ta content ( ppm) Sample ID Concentrate Raw (3.1) (2.5) (2.8) (1.7) (2.6) 0 2000 4000 6000 8000 10000 12000 14000 16000 LREE (Ʃ La. Ce, Nd, Pr) content (ppm) Sample ID Concentrate Raw a) c) Figure 5. Comparison of Nb, Ta and LREE (Σ La, Ce, Nd, Pr) content of raw samples and corresponding Mozley concentrates. Concentration factors (Mozley concentrates /raw samples) are shown in parentheses. b) Mineral concentrators such as the The Mine & Smelter Supply Co Wilfley shaking table #13 used in this study are a common tool in mining and exploration activities. Wilfley shaking tables separate silt and sand sized material by mineral density. Simple to calibrate and maintain, it processes a continous feed of material. Informaiton regarding the Wilfley concentrator presented here is derived from Mackay et al. (2015a). BCGS Geofile 2015-06 Mackay, D.A.R., Simandl, G.J., Ma, W., Grcic, B., Redfearn, M., Luck, P., and Li, C. 2015. Assessment of Mozley and Wilfley shaking tables for concentrating carbonatite indicator minerals, Aley carbonatite, British Columbia, Canada. British Columbia Ministry of Energy and Mines, British Columbia Geological Survey, Geofile 2015-06. Table 1: Potential carbonatite indicator minerals. Expected ranges in pathfinder element content (Wt. %). Modified from Mackay et al. (2015a). Mineral Chemical Formula Density (g/cm 3 ) Nb 2 O 5 Ta 2 O 5 TREO Pyrochlore (Ca,Na) 2 (Nb,Ti,Ta) 2 O 6 ( O,OH,F) 4.2–6.4 34.2–86.8 0–4.3 2.6-6.0 Columbite-(Fe) (Fe,Mn)(Ta,Nb) 2 O 6 5.3–7.3 46.8–81.2 0–31.2 n.a. Fersmite (Ca,Ce,Na)(Nb,Ta, Ti) 2 (O,OH,F) 6 4.69–4.79 66.0–70.1 0–16.9 4.8 Monazite (Ce,La,Nd,Th)PO 4 4.8–5.5 n.a. n.a. 59.2 Zircon ZrSiO 4 4.6–4.7 n.a. n.a. 0.1–4.4 Bastnaesite Ce(CO 3 )F 4.95–5.00 n.a. n.a. 73.6–78.1 Synchysite Ca(Ce,La)(CO 3 ) 2 F 3.90–4.15 n.a. n.a. 47.8 Apatite Ca 5 (PO 4 ) 3 (OH,F,Cl) 3.16–3.22 n.a. n.a. 0.5–5.5 Barite BaSO 4 4.48 n.a. n.a. n.a. Celestine SrSO 4 3.9–4.0 n.a. n.a. n.a. Magnetite Fe 3 O 4 5.1–5.2 n.a. n.a. n.a. Arfvedsonite Na 3 [(Fe,Mg) 4 Fe]Si 8 O 22 (OH) 2 3.44-3.45 n.a. n.a. n.a. Richterite Na(Ca,Na)(Mg,Fe) 5 (Si 8 O 22 )(OH) 2 3.09 n.a. n.a. n.a. Aegerine NaFeSi 2 O 6 5.50–5.54 n.a. n.a. n.a. Perovskite CaTiO3 4.0-4.3 n.a. n.a. n.a. n.a. = not applicable AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3408x - 279.87 R² = 0.9636 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0 5000 10000 15000 20000 25000 30000 Nb in Raw Samples (ppm) Nb in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.6258x + 50.75 R² = 0.8699 0 200 400 600 800 1000 1200 1400 1600 0 500 1000 1500 2000 2500 Sr in Raw Samples (ppm) Sr in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3509x - 0.0842 R² = 0.9638 0 10 20 30 40 50 60 0 50 100 150 U in Raw Samples (ppm) U in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3078x + 630.71 R² = 0.9378 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 0 5000 10000 15000 20000 25000 LREE in Raw Samples (ppm) LREE in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3369x + 12.341 R² = 0.9584 0 20 40 60 80 100 120 140 160 0 100 200 300 400 Ta in Raw Samples (ppm) Ta in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3459x + 8.1099 R² = 0.9705 0 20 40 60 80 100 120 140 0 100 200 300 400 Y in Raw Samples (ppm) Y in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.4764x + 143.36 R² = 0.9864 0 200 400 600 800 1000 1200 0 500 1000 1500 2000 Ba in Raw Samples (ppm) Ba in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3915x + 9.1282 R² = 0.9866 0 50 100 150 200 250 300 350 400 450 0 200 400 600 800 1000 1200 Th in Raw Samples (ppm) Th in Concentrate (ppm) AL-13-01 AL-13-18 AL-13-10 AL-13-07 AL-13-16 y = 0.4304x - 71.438 R² = 0.8077 0 2000 4000 6000 8000 10000 12000 14000 16000 0 5000 10000 15000 20000 25000 30000 35000 P in Raw Samples (ppm) P in Concentrate (ppm) AL-13-07 AL-13-10 AL-13-18 AL-13-16 AL-13-01 y = 0.3516x + 11.443 R² = 0.959 0 200 400 600 800 1000 1200 0 500 1000 1500 2000 2500 3000 3500 Zr in Raw Samples (ppm) Zr in Concentrate (ppm) Figure 6. Comparison of Nb, Ta, LREE (Σ La, Ce, Pr, Nd), Y, Sr, Ba, U, Th, P, and Zr content (determined by pXRF) of the 125-250 fraction from before and after Mozley C800 separator μm processing. High coefficients of determination (R ) for most pathfinder elements indicate that 2 processing consistently concentrated corresponding carbonatite indicator minerals (shown in boxes). Error bars (2σ) are based on repeated portable X-ray fluorescence analyses of standards as described in Luck and Simandl (2014). AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.1829x + 274.16 R² = 0.9649 0 1000 2000 3000 4000 5000 6000 0 5000 10000 15000 20000 25000 30000 35000 Nb in Raw Samples (ppm) Nb in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.194x + 20.212 R² = 0.8482 0 20 40 60 80 100 120 140 160 0 100 200 300 400 500 600 Ta in Raw Samples (ppm) Ta in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.1563x + 1108.2 R² = 0.9577 0 1000 2000 3000 4000 5000 6000 0 5000 10000 15000 20000 25000 LREE in Raw Samples (ppm) LREE in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.2019x + 20.786 R² = 0.9381 0 20 40 60 80 100 120 0 100 200 300 400 500 Y in Raw Samples (ppm) Y in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.153x + 623.83 R² = 0.0089 500 600 700 800 900 1000 1100 750 800 850 900 950 1000 1050 1100 Sr in Raw Samples (ppm) Sr in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-18 AL-13-16 y = 0.2084x + 269.16 R² = 0.9259 0 200 400 600 800 1000 1200 0 1000 2000 3000 4000 Ba in Raw Samples (ppm) Ba in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 y = 0.226x + 2.0727 R² = 0.9541 0 10 20 30 40 50 60 0 50 100 150 200 U in Raw Samples (ppm) U in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 y = 0.2601x + 20.232 R² = 0.9532 0 50 100 150 200 250 300 350 400 450 0 500 1000 1500 Th in Raw Samples (ppm) Th in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 y = 0.1658x + 87.989 R² = 0.9668 0 100 200 300 400 500 600 700 800 0 1000 2000 3000 4000 5000 Zr in Raw Samples (ppm) Zr in Concentrate (ppm) AL-13-01 AL-13-07 AL-13-10 AL-13-16 AL-13-18 y = 0.5103x - 1115.3 R² = 0.7174 0 2000 4000 6000 8000 10000 12000 14000 16000 0 5000 10000 15000 20000 25000 30000 P in Concentrate (ppm) P in Concentrate (ppm) Figure 11. Comparison of Nb, Ta, LREE (Σ La, Ce, Pr, Nd), Y, Sr, Ba, U, Th, P, and Zr content (determined by pXRF) in Wilfley table concentrates and raw samples. High coefficients of determination (R ) for most pathfinder elements indicate that processing consistently 2 concentrated corresponding indicator minerals (shown in boxes). Error bars (2σ) are based on repeated portable X-ray fluorescence analyses of standards as described in Luck and Simandl (2014). 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 Aley Carbonatite pyrochlore columbite-Fe fersmite pyrochlore columbite-Fe fersmite bastnaesite monazite synchesite allanite bastnaesite monazite synchesite allanite celestine barite monazite monazite apatite monazite zircon pyrochlore columbite-Fe fersmite pyrochlore columbite-Fe fersmite bastnaesite monazite synchesite allanite bastnaesite monazite synchesite allanite celestine barite monazite monazite apatite monazite zircon Nb Ta LREE Y Zr P Th U Ba Sr Fe Table 3: Comparison of coefficients of 2 determination (R ) for elemental abundances in mineral concentrates and raw samples 0.99 0.96 0.99 0.91 0.87 0.97 0.96 0.96 0.94 0.97 0.96 0.93 0.95 0.95 0.71 0.01 0.97 Mozley C800 Wilfley #13 0.96 0.85 0.96 0.94 0.97 Min Mean Max Min Mean Max Nb 2.8 3.3 3.7 3.9 4.8 5.6 Ta 2.1 2.4 2.9 2.3 3.6 4.9 LREE 1.7 2.5 3.1 1.8 3.9 5.1 Y 2.1 2.5 2.8 2.1 3.4 4.2 Zr 2.2 2.7 3.3 2.4 4.4 5.6 P 2.0 2.4 2.6 1.8 2.2 2.4 Th 2.2 2.5 2.6 2.7 3.4 3.9 U 2.4 2.8 3.3 2.5 3.8 4.5 Ba 0.9 1.5 1.8 1.0 2.4 3.7 Sr 1.4 1.5 1.6 1.0 1.2 1.4 Fe 1.7 2.3 2.7 1.7 3.5 4.6 Mozley C800 Wilfley #13 Table 2: Comparison of concentration factors for Mozley and Wilfley shaker tables Conclusions Both Mozley C800 and Wilfley #13 effectively concentrate carbonatite indicator minerals in stream sediments Both tables produce concentrates with a predictable relationship to raw samples The Mozley C800 is more suitable for small initial sample weight (75 - 100 g) while the Wilfley #13 is more suitable for larger sample weights (> 380 g) Risk of contamination is lower and clean-up is easier with the Mozley C800 table Potential carbonatite indicator minerals
