The Brooklyn (Lot 796) and Idaho (Lot 891) mines are situated on a mineralized zone crossing the valley of Twin Creek, about 700 metres northwest of the Phoenix pit (082ESE020). The Stemwinder mine (082ESE014) is 300 metres east of the Brooklyn and Idaho workings. See Phoenix for additional details on development, geology and mineralization.

Production for the Brooklyn, Idaho and Stemwinder from 1900 to 1960 totals 292,834, yielding 854,990 grams of gold, 3,430,655 grams of silver, and 3,567,397 kilograms of copper. Production after 1960 is included with Phoenix (Knob Hill). In the period 1963 to 1964, open pit excavations in a 75 by 150-metre area near the Idaho shaft yielded an additional 137,333 tonnes of ore. Subsequently the area became the main tailings pond for the Phoenix mine. During 1966 and 1967, an open pit on the Stemwinder claim produced 63,339 tonnes of ore.

The mineralized zone is an elongated pear shaped form, broad and shallow at the south, narrowing and becoming steeper to the north until it is enclosed by almost vertical walls of limestone, as exposed by the Brooklyn 'glory hole'. The sharpstone beds lie to the east and the limestone to the west. The floor is mainly limestone with some sharpstone conglomerate in the southern part. The length is about 564 metres, and the width varies from about 122 metres in the south to less than 15 metres in the extreme north.

The Brooklyn mine, at the north end of the mineralized zone, was developed from two glory holes at surface and a number of underground stopes serviced by a 130-metre inclined shaft with working levels at 24, 46, 76, 91, and 106 metres. The total recorded ore production is 258,290 tonnes, which includes the two main periods of operation from 1900 to 1908 and 1937 to 1940.

The Idaho mine, at the south end of the mineralized zone, includes an inclined shaft and two levels, the deepest of which connects with the 76-metre level of the Brooklyn mine. A total of approximately 2300 metres of tunnelling was completed at the Brooklyn and Idaho mines by the first closing of operations in 1908.

The Brooklyn and Idaho claims were staked in 1891 by J. Taylor, D. McLaren, and associates and Crown-granted in 1898 and 1899, respectively. The Dominion Copper Company, Limited began development work in May 1899. By 1906, the workings included 3 shafts and about 2.4 kilometres of drifts and crosscuts. The mine produced a considerable tonnage, largely from the Brooklyn claim, during the period 1901 to 1908, although production was not continuous during that period. Meanwhile the ownership underwent several reorganizations and operations were carried by the Montreal & Boston Consolidated Mining and Smelting Company, Limited, the Dominion Copper Company, and finally the New Dominion Copper Company, Limited. Subsequent operations were confined largely to the Rawhide claim (082ESE026) which is located 1800 metres to the southeast. In 1910, a majority interest in New Dominion Copper was acquired by The British Columbia Copper Company, Limited, Spokane. In 1915, this company came under control of Canada Copper Corporation, Limited, of New York. The Brooklyn workings were pumped out in 1918 and rehabilitation work began but the company closed out all its operations in November of that year.

Brooklyn-Stemwinder Gold Mines, Limited, was incorporated in 1933 to acquire the Stemwinder, Standard Fraction, Joker, Montezuma, New York, and Brooklyn claims. Intermittent exploration work was carried out by the company and by lessees. W.E. McArthur leased the property in 1937 and some 30 metres of drifting and 90 metres of raising was done. Production is believed to be from the Brooklyn. The lease was given up in March 1940. The company resumed exploration work in 1946 with a diamond drill program which was completed in 1947. Several zones of mineralization were indicated and these were investigated by underground work during 1948-1949, including 80 metres of crosscut adit, 38 metres of drifting, and 360 metres of diamond drilling in 22 holes. The mine closed in 1949 and the company charter was surrendered in 1952. Columbia Copperfields Ltd. apparently held the property in the 1950's but no work was reported. Continental Consolidated Mines Ltd. acquired the property in 1959 and underground work was carried on until mid December; ore recovered from the Stemwinder workings was shipped the following year to the Granby concentrator. The Granby Mining Company Limited purchased the property in 1963.

At the Brooklyn occurrence, talc is associated with serpentinized ultramafic rocks which are widely distributed in the area of the Phoenix mine. The ultramafic rocks show massive and schistose phases; sheared margins are often altered to talc and talc-carbonate schist. The contacts with surrounding country rock are intensely sheared. The ultramafics are Mesozoic in age, intruding mainly Triassic Brooklyn Group volcaniclastics and sediments and Cretaceous Greenwood granodiorite. Talc is found north of the Phoenix pit, not exposed on surface but in drill holes on the Brooklyn claim. The talc occurs below a major thrust which separates Brooklyn rocks from basement rocks of the Upper Paleozoic Knob Hill Group (Personal Communication - Church, 1988).