Bachelor Creek Gold Mine

Geology

TRAVERSES IN THE UPPER BACHELOR CREEK BASIN INDICATE THAT IT IS UNDERLAIN, IN PART, BY LIGHT GRAY OR RUSTY-WEATHERING FELSIC SCHISTS AND QUARTZITES AND BY ABUNDANT GRAPHITIC SCHIST AND QUARTZITE. SULFIDE MINERALS APPEAR TO BE CONCENTRATED IN STRATIFORM LAYERS, ESPECIALLY IN THE GRAPHITIC ROCKS. IN SOME HAND SPECIMENS, SULFIDES MAKE UP 15 TO 20 PERCENT OF THE ROCK. PYRITE IS THE MOST COMMON SULFIDE, AND CHALCOPYRITE AND ARSENOPYRITE ARE PRESENT IN MANY OF THE ROCKS. PYRRHOTITE IS COMMON IN THE GRAPHITIC ZONES. BOTH FELSIC AND GRAPHITIC SCHISTS CONTAIN ELEVATED ABUNDANCES OF GOLD, COPPER AND TUNGSTEN. THE FELSIC SCHISTS AND ASSOCIATED LIGHT-COLORED QUARTZITES CONTAIN UP TO 240 PPB GOLD, 4300 PPM COPPER, 2100 PPM AS, 4 PPM SILVER, 4. 5 PPM SB, 130 PPM SB, 14 PPMLEAD, 90 PPM SN AND 3100 PPM W. IN THESE ROCKS GOLD CORRELATES WITH COPPER, AND TO A LESSER EXTENT, WITH ARSENIC. HIGH TUNGSTEN-TIN VALUES INVERSELY CORRELATE TO GOLD-BASE METAL VALUES. GRAPHITIC SCHISTS AND QUARTZITES ARE LESS WELL MINERALIZED WITH CONCENTRATIONS OF GOLD TO 180 PPB, COPPER TO 1600 PPM AND W TO 110 PPM (T. E. SMITH AND OTHERS, 1987, P. 6-10 TO 6-11 ). BEDROCK IN THE AREA IS COMPOSED OF BOTH SCHIST AND GRANITE PORPHYRY. BEDROCK SCHIST IS PRIMARILY QUARTZ-MICA, QUARTZITIC, AND CARBONACEOUS. THESE PALEOZOIC AND (OR) PRECAMBRIAN SCHISTS ARE CUT BY A 75 FOOT THICK SILL-LIKE BODY OF GRANITE PORPHYRY. THE SCHISTOSITY AND SILL STRIKE N 60 E. GRAVELS ARE THIN (7 TO 8 FEET THICK) OR ABSENT AND ARE THAWED. GRAVELS ARE COMPOSED OF SCHIST, ABUNDANT VEIN QUARTZ, AND SOME GRANITE PORPHYRY CLASTS. THE ONLY GOLD OCCURRENCE REPORTED IS ON A LOW, 20 FOOT THICK GRAVEL BENCH ON THE EAST SIDE OF THE CREEK (PRINDLE, 1910, P. 208-209 ). GRAVEL ON A LOW BENCH EAST OF THE STREAM WAS SLUICED IN 1910 (COBB, 1973, P. 123, [B 1374] ). A MAN RECENTLY REPORTED FINDING A 1. 2 OUNCE GOLD NUGGET ON BACHELOR CREEK (LAMPRIGHT, 1996, P. 55).