Evaluation of vein quartz, Montgomery County, North Carolina for its suitability as a quartz resource

whame ttonv Branch Founlair Hill/ "SWELL HERTFO HALIFAX 1Л1АТА1 BERTIE GUILFORD MASH IREDELL i CHATHAM BURKE IAIAKE IAWXIOO CATAI LINCOLN RUTHERFORD HARNETT GASTON UUAYME FOLK WORE LENOIR STANL' MRCO CLAY HOKE BLADEN PENDER IRUNSWCK Left - table shows chemical analysis before and after leaching. For additional information: Jeffrey C. Reid, North Carolina Geological Survey 1612 Mail Service Center Raleigh, North Carolina 27699-1612 919.733.2423 - http://www.geology.enr.state.nc.us Email: jeff.reid@ncmail.net EVALUATION OF VEIN QUARTZ, MONTGOMERY COUNTY, NORTH CAROLINA FOR ITS SUITABILITY AS A QUARTZ RESOURCE MENSAH-BINEY, Robert, North Carolina State University’s Minerals Research Laboratory, 180 Coxe Ave., Asheville, NC 28801, REID, Jeffrey C., North Geological Survey, 1612 Mail Service Center, Raleigh, NC 27699-1612. Stock work vein quartz ~20 kg samples from metavolcanic rocks from Montgomery County, North Carolina, were evaluated for their quartz resource suitability. Preliminary processing evaluation and chemical analysis of the quartz concentrates from the two samples indicated low impurity levels to justify further chemical treatment to produce ultra-high purity quartz. The processing steps involved crushing, grinding to produce 60 x 140 mesh, flotation to remove mica, iron minerals and feldspar impurities, magnetic separation of the clean quartz, sizing and hydrofluoric / hydrochloric acid leach to produce ultra-high purity quartz product (lota Grade). The chemical analysis of the quartz concentrates before and after leaching is shown in the table below (unleached product is after magnetic separation, leached product is after leaching with HF/H2S04). Although chemical leaching resulted in significant reduction in Fe and Mg, the impurity level for Al, Ca, Na, К was too high for ultra-high purity quartz. Additional process evaluation is needed to remove additional Al, Fe, Ca, K, and Na to produce high-pure quartz (Quintas Grade). Granular high purity quartz (HPQ) is used in the manufacture of optical glasses and for high purity silica glasses for semiconductor silicon in silicon computer and memory chip production (high purity crucibles for growing the silicon), for high intensity lighting applications and for standard and fiber optical components. HPQ chips (lascas) are used in the manufacture of piezo-electric quartz crystals (cultured quartz). Some of the lower purity HPQs are used in the ceramic industry for high heat intensity applications such as the heating tile for the space shuttle. The quartz composition is shown in the table below. No gold was detected at the ppb level in three composite bulk samples or one duplicate bulk sample. Above - Outcrop sample displays primary hydrothermal ‘plumbing’ and at least three generations of quartz. Above - outcrop and outcrop detail of example quartz exposure in Montgomery County, NC. Below - location map showing location of Montgomery Co. North Carolina and generalized geology from the ‘Geologic Map of North Carolina’ (1985). r* f /-»-v Sample Leached Al (ppm) Ca (ppm) Fe (ppm) К (ppm) Li (ppm) Na (ppm) Ti (ppm) Mg (ppm) Zr (ppm) Mill Creek #1 Unleached 15.4 15.6 5.26 1.57 0.31 14.7 0.31 0.21 0.29 Mill Creek #1 Leached 12 7.57 0.08 1.23 0.36 10.8 0.17 0.09 0.01 Little River Unleached 19.3 7.74 3.69 1.7 0.25 22.5 0.43 0.19 0.14 Little River Leached 15.8 3.8 0.03 1.88 0.67 19.7 0.37 0.09 0.01