Brimstone works to revive Mayflower

The past-producing Mayflower gold-silver mine in southwestern Montana could find itself back in business.

Last year, Brimstone Gold (BSC-V) acquired the mine from two privately owned Montana companies. It was discovered in the 1890s and later became part of the holdings of Anaconda, which operated it from 1935 to 1942. It was mined again, under a lease agreement, from 1958 to 1961.

Situated 30 miles southeast of Butte, in Madison Cty., the Mayflower mine has produced more than 225,000 oz. gold and 875,000 oz. silver from about 143,700 tons of ore. The average grade has been 1.5 oz. gold and 6.15 oz.

silver per ton — high enough for the ore to be shipped directly to a smelter for processing.

Intent on returning the mine to production, Brimstone is carrying out rehabilitation work, to be followed by a 10,000-ft. underground drill program.

A rebuilt 400-hp double-drum hoist and headframe have been installed. The shaft has thus far been rehabilitated to the 600-ft. level, below which workings remain flooded. The historic workings reach a total depth of 1,582 ft.

Dewatering, now under way, is expected to last three to four weeks.

The Mayflower is a structurally controlled epithermal vein deposit. Past production came from two sets of fault-controlled vein-type orebodies hosted in Cambrian-age Meagher limestone, adjacent to the high-angle, east-northeast-trending Mayflower fault, near its intersection with the northeast-trending Clark fault.

Initial exploration drilling will target the eastern extension of the Mayflower vein, below the 1,360-ft. level. Anaconda drilled two exploration holes from this level in 1961. One hole intersected 7 ft. of 2.02 oz. gold and 22.6 oz. silver at a depth of 300 ft. below the 1,360-ft. level. The second hole intercepted 4.6 ft. of 0.43 oz. gold and 4.87 oz. silver at a 375-ft. depth below the level.

Drilling suggests a probable reserve of 5,599 tons grading 1.75 oz. gold and 13 oz. silver per ton for this area, equivalent to 9,800 oz. gold and 72,800 oz. silver.

Anaconda carried out further drilling on the property between 1982 and 1984.

Though results from 11 holes were mixed, a 6.5-ft. intercept grading 0.31 oz. gold and 4.53 oz. silver showed potential in the West Mayflower deposit.

The most promising targets for Brimstone are the lateral and vertical extensions of the previously mined Mayflower and West Mayflower ore shoots.