The property is located between elevations of 1219.2 metres and 1981 metres on the southeast side of Hellroaring Creek, 4.8 kilometres south of St. Mary Lake and 19 kilometres southwest of Kimberley.
The Warhorse is underlain by intensely sheared argillaceous quartzite of the Middle Proterozoic Aldridge Formation, Purcell Supergroup. Mineralization occurs in quartz veins and lenses up to 1 metre wide. The veins are well-mineralized with galena, sphalerite, pyrite and locally, arsenopyrite. Some siderite also occurs locally.
The showings were reportedly staked in about 1895 and development work prior to 1910 was done in two adits, one of which was on the Iron Duke claim. The property was owned in 915 by N.A. Wallinger and associates. In 1920 A.H. Mayland of Calgary acquired an interest in the property. Four claims were Crown-granted in 1925, the Warhorse (Lot 13077) to Messrs. Wallinger, Bennett, and Mayland, and the Hope, Granite, and Faith (Lots 13078-13080 respectively) to Mayland. The property was known from about 1926 as the Boy Scout group. Development work, financed by Mayland and associates, was begun in a new (No. 3) adit in 1926 and continued into 1930. Cranberra Mines, Limited was incorporated as a private company in January 1930 by Mayland and associates to develop the property. When work ceased in 1930 the No. 3 adit had been driven as a crosscut for 104 metres and drift for more than 152 metres, with crosscuts near the face driven 21 metres northeast and 15 metres southwest. The old No. 1 adit had been driven to a length of about 49 metres. The No. 2 adit was driven in the footwall of the vein for most of its 91 metre length, with four crosscuts extending into the hangingwall.
Staple Mines and Minerals Limited held an option on the property during the first half of 1949 but no work was reported. Lake Expanse Gold Mines, Limited optioned the property from R. Bennett of Cranbrook late in 1949. Surface diamond drilling was carried out on the Warhorse claim.
Thomas Consolidated Mines, Inc., of Spokane, optioned the property late in 1950. Development work began in 1951 in a new 1387 metre elevation adit, about 213 metres vertically below No. 1 adit. By 1956, a total of 1245 metres of drifting and crosscutting, and 500 metres of diamond drilling had been carried out in the new adit. Work ceased at the end of July 1956.
St. Mary's Silver Lead Ltd. was incorporated in September 1965 to acquire the property. The company name was changed to Hellroaring Silver Lead Ltd. in November 1965, and to St. Mary's Mines Ltd. in April 1968. Work by previous operators had indicated approximately 23,000 to 27,000 tonnes at 6 per cent lead, 8 per cent zinc, 171 grams per tonne silver (Northern Miner, Dec. 30, 1965). In 1969 the company carried out 610 metres of surface diamond drilling in 11 holes.
