Details


SMDI #
1221
Current Showing Name
Gulch Mine; Gulch Uranium Zone/Deposit; Arkose No. 2 Adit
Historical Showing Names
Gulch Mine; Gulch Uranium Zone/Deposit; Arkose No. 2 Adit
Company Name
Project Name
UTM Easting (NAD83 Z13)
281124.4400
UTM Northing (NAD83 Z13)
6596052.5300
NTS Sheet
074N07
TRM (Township-Range-Meridian)
120-17-3
Primary Commodities
Uranium
Associated Commodities
Arsenic, Cobalt, Copper, Lead, Nickel
Discovery Type
Status
Deposit: Advanced Exploration
Geological Details
The Gulch Mine is located on a prominemt escarpment on Black Bay approximately 20 km (12.4 miles) southwest of Uranium City. The adit is located 30 m (98.4 ft) from the shoreline. The main structural element which controlls the ore at the Gulch Mine is the Black Bay fault. The fault strikes N52°E and dips 65° to 69°SE in the vicinity of the 'gulch'. The fault was exposed in underground workings and characterizing gouges, ranging from 3 to 24 inches (7.6 cm to 0.6 m) in thickness, can be seen. On the hanging wall side of the fault, the bedrock consists of a sequence of brecciated arkoses with minor siltstone and conglomerate of the Helikian Martin Formation overlying brecciated and mylonitized Aphebian granitic rocks. The footwall rocks consist of brecciated and red-altered meta-argillites and quartz feldspar gneisses which are, locally, rich in chlorite and epidote. Most of the footwall rocks strike parallel to the Black Bay Fault and dip southeast at a flatter angle than the fault. In the footwall rocks, three sets of mineralized One set strikes N25°W and 2 sets strike N52°E. Most of the pitchblende is associated with the northwest-trending fractures. It occurs as small veinlets from up to 1/8 inches wide to paper-thin smears which coat fracture surfaces. Variable amounts of pyrite, carbonate, and graphite are present in the veins; chalcopyrite, galena, and smaltite, ((Co,Ni)As2-3), have been reported. Underground work outlined eleven ore shoots, which vary from 60 to 160 feet (18.3 to 48.8 m) in length and 4 to 14 feet (1.2 to 4.3 m) in width, between the 500 foot and 800 ft (152 and 244 m) levels.
Geological Domain
Beaverlodge
Host Rocks
Host Minerals
Arsenopyrite
Indicators
Exploration History
7/26/1989 A group of 21 claims, straddling the Black Bay fault, was acquired by New Bidlamaque Mines in 1953. Several promising uranium discoveries were made on the GULCH and ARKO Claims (the above mention 21 claims) prior to 1953, and detailed geological mapping and radioactive surveys during the summer of 1953 (AF 74N07-0072) indicated that a diamond drilling program was warranted. Sampling and rock trenching carried out in October proved encouraging and Gulch Mines Ltd., in the following year, was formed to develop the property. Between 1953 and 1957, geological mapping, radiometric surveys, trenching, sampling and diamond drilling were used to delineate the property. A 831 ft (253.3 m) shaft with three levels was sunk. Underground drilling and lateral work further delineated the deposit. The main showing, or the Gulch Zone, was initially investigated by 3 drill holes. Drill results were disappointing but the structural setting of the property was revealed. Drilling through the Black Bay Fault into the Aphebian footwall rocks commenced. The first hole hit pitchblende. This led to a 31 hole (19,370 ft) drill program that outlined a deposit of. Deposit reserves were calculated at this time. The deposit is open at both ends of the structure. In January 1955, an adit, located 400 ft (121.9 m) southwest of "Gulch", was driven 260 ft (79.3 m) into the Black Bay escarpment. From this adit, a shaft was sunk to a depth of 525 feet (160.0 m) and stations were cut at 350 and 500 feet below the lake level. In August 1955, the shaft was deepened to 830 feet (253.0 m) and a further 2 levels were established at at 650 and 800 feet below the lake level. In all 5,456 feet of lateral workings were dug, mostly on the 500 foot level and about 35,000 feet of drilling was done on 3 levels. Underground operations were ended on March 1957. Development work on the 500 foot level of the mine outlined 11 oreshoots ranging in length from 60 to 160 feet (18.3 and 48.8 m) and in width from 4 to 14 feet (1.2 to 4.3 m). Reserves were re-calculated in March of 1957. The continuance of the mineralized fractures to the 650 and 800 foot (198.1 and 243.8 m) levels was established with no significant change in size or grade of the ore shoots. Between 1967 and 1968, Gunnex Ltd and Gulch Mines Ltd completed further geological and geophysical surveys on the property. In 1967, they completed an extensive exploration program that included radiometric prospecting and geological mapping in an effort to locate further orebodies on the footwall side of the Black Bay fault. 20 drill holes were put down between 1967 and 1968 for a total footage of 9,478 ft. Only one hole, which was spudded near the old underground workings, gave encouraging assays. 18 more holes were drilled to test a showing located a few hundred feet from the Gulch Mine. This zone was tested over a strike length of 4,000 feet. Between 1974 and 1976, nearby underwater radiometric anomalies were drill tested. In 1975, the deposit drill-indicated reserves of the Gulch Deposit were published in the 1989 GSC Canadian Deposits Not Being Mined. In 1988, Kelmet Resources Ltd. optioned the property.
Production History
Production Period: 1955-01-01 to 1957-03-01 (underground) In 1955, an 260 ft (79.3 m) adit was driven, a 830 ft (253.0 m) shaft was sunk from the adit, and lateral work was started. Underground operations ended in March of 1957. No production figures have been reported.
Reserves and/or Resources
1975-01-01 Drill indicated reserves: 201,000 tons of ore grading 0.09% U3O8 (0.05% cut-off) with a further 315,000 tons of possible reserves grading 0.09% U3O8. Summary: Historic possible reserve of 315,000.00 ton - Uranium: 315,000.00 ton @ 0.09 Historic indicated resource of 201,000.00 ton - Uranium: 201,000.00 ton @ 0.09 % (Cutoff: 0.05) 1957-03-01 Total deposit reserve: 854 tons per vertical foot grading 0.121% U3O8. Summary: Historic resource (unspecified) of 854.00 ton - Uranium @ 0.12 % 1957-01-01 A deposit of approximately 598,000 tons that grade 0.126% U3O8 to a depth of 400 feet. The deposit is open at both ends of the structure. Summary: Historic reserve (unspecified) of 598,000.00 ton - Uranium: 598,000.00 ton @ 0.126 %
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