The Rocher Deboule mine is located on the northeastern portion of Rocher Deboule Mountain, 11 kilometres south of Hazelton. The Rocher Deboule and Victoria mines (093M 072) were discovered before World War 1. From 1915 to 1954, 123,395 tonnes produced 2,653,086 grams of silver, 157,226 grams of gold, 2,840,966 kilograms of copper, 341 kilograms of lead, 34,692 kilograms of tungsten and 3,274 kilograms of zinc.
Hornfelsic greywackes and siltstones of the Jurassic to Lower Cretaceous Bowser Lake Group are intruded by the Rocher Deboule porphyritic granodiorite stock of the Late Cretaceous Bulkley Plutonic Suite. Dikes are not abundant but consist of fine-grained quartz monzonite, fine-grained diorite and porphyritic andesite. There are five main vein structures which are numbered from 1 to 5, the No. 2 vein being the most important. The veins occur over a 750 metre width, within parallel structures which generally strike 075 degrees and dip 35 to 65 degrees north. The veins are 0.5 to 2.4-metres wide and up to 700 metres long.
Three distinct stages of mineralization are apparent. The first stage is pegmatitic and includes hornblende, quartz, feldspar, apatite, magnetite, scheelite, molybdenite and uraninite. The second and main stages include chalcopyrite, glassy quartz, arsenopyrite, cobaltite, safflorite, glaucodot and pyrrhotite. The third stage includes milky quartz, siderite, calcite, tetrahedrite, sphalerite, galena, pyrite and possibly chalcocite. Secondary minerals include malachite, erythrite and limonite.
The Rocher Deboule property was located in 1910 by Sargeant and Munroe of Hazelton, BC, which was acquired, in 1911, by Rocher Deboule Copper Company of Salt Lake City, Utah. Development on the property was done under lease by the Montana Continental Development Company, a company owned by the principals of Rocher Deboule Company. Ore was mined and shipped from the upper part of the Number 4 vein from April 1915, until February 1916, when the property reverted to its owners. Development work, previously neglected, was done on the Number 2 and 4 veins and by 1917 a 3100-foot (945 metres), known as the 1201, was driven from the bottom of the valley of Juniper Creek to intersect all known veins. Production in 1917-18 was largely from the Number 2 vein and was much less than in the previous two years, although the copper-gold grade was good. The mine was closed in October 1918, because of a lack of developed ore and a drop in copper price.
In 1929 Aurimont Mines Limited who mined and shipped some ore leased the property. In 1930 Hazelton Copper Mines Limited again leased the property but no production was done. The property remained inactive until 1950 when it was acquired by Western Uranium Cobalt Mines Ltd. whose initial interest was a means of access to the adjacent Victoria mine; the company immediately began to investigate Rocher Deboule as a source of copper and precious metal ore and as a prospect for uranium-cobalt. In 1950, a slide that blocked the portal of the 1200 level was cleared, the upper levels were rehabilitated and construction of a camp was begun. A 100-ton per day mill was put in operation in May 1952, and shut down in November of the same year because the grade was lower than expected. Part of the mill equipment was moved to the nearby Red Rose tungsten mine which was owned by the same company. After the Red Rose mine was closed in 1954, equipment from both mines was sold.
During 1987–1989, Southern Gold Resources Limited completed drill testing and sampling of the No. 2 Vein and an estimated a potential reserve of 49 800 tonnes averaging 2.69 per cent copper, 208.1 grams per tonne silver and 3.51 grams per tonne gold (Property File Placer Dome Quin, 1989). The Numbers 4 and 2a veins were examined during this time with encouraging results, but work was limited by accessibility of the old workings and an unstable slide in the vicinity of the outcrops. Sampling of the Number 4 vein, on the 300 foot level, returned an average of 2.17 grams per tonne gold, 88.1 grams per tonne silver and 4.12 per cent copper over an average of 0.78 metre from 24 samples (Property File Placer Dome, Quin, 1989).
In 1991, the indicated ore reserve of the No. 2 vein was estimated at 37,000 tonnes grading 11.66 grams per tonne gold equivalent; the Number 4 vein has indicated reserves of 17,000 tonnes of the same grade respectively (Open File 1992-1). A radioactive sample over 38 centimetres from the No. 2 vein assayed 0.019 per cent equivalent uranium (Geological Survey of Canada Memoir 223 (Rev.)). A sample taken in 1949, assayed 0.21 per cent equivalent uranium (Geological Survey of Canada Economic Geology 16, 1952).
The Number 2 Porphyry zone is a bulk tonnage target estimated to be 757 metres long, 605 metres deep and an average of 12 metres wide. Samples from a trench on the quartz stockwork in this zone assayed up to 30.5 grams per tonne gold and 0.35 per cent cobalt over 2.4 metres (George Cross Newsletter #228, November 26, 1990).
Total indicated (probable/possible) reserves at Rocher Deboule are 54,000 tonnes grading 2.70 per cent copper, 207.4 grams per tonne silver and 3.5 grams per tonne gold or 11.66 grams per tonne gold equivalent (George Cross Newsletter #228, November 26, 1990).
In 1998, Hunter Exploration Group conducted prospecting on the Rocher DeBoule (Assessment Report 25674).
The property was dormant until May 2001, when American Manganese Inc. (former known as Rocher Deboule Minerals Corporation) reported that it had acquired four mineral claims consisting of 53 units (1325 hectares) centred around the main underground working at the headwaters of Juniper Creek (www.americanmanganeseinc.com).
During the period of October 2001 and May 2002, geological surveying and geochemical rock and stream sediment sampling was carried out on the Rocher Deboule and Victoria mines. Aside from the expected copper-silver-gold values of economic interest, which returned values up to 14.8 grams per tonne gold, greater than 10 per cent copper and 399.6 grams per tonne silver, the Rocher Deboule Numbers 2, 3 and 4 veins contained variable molybdenite, sphalerite, arsenopyrite and safflorite (Assessment Report 26984, 29338).
In 2004, three rock-chip samples were collected from the vicinity of the Number 4 vein of the Rocher Deboule mine. The samples were analyzed geochemically and all results were in excess of 10,000 parts per million copper, from 0.79 to 1.8 grams per tonne gold and 7.1 to 100 grams per tonne silver (Assessment Report 27558, 29338).
In March 2007, Rocher DeBoule Minerals Corp contracted Fugro Airborne Survey Corporation to complete a Dighem electromagnetic, magnetic, radiometric geophysical survey over the Rocher Deboule property in a survey block amounting to 1089 line kilometres. The survey identified a strong positive anomaly (60 000 to 62 000 nanoteslas, approximately 3000 to 5000 nanoteslas above average) over an area of approximately 0.5 by 1 kilometre (V STOCKWATCH, November 20, 2012; Assessment Report 29338). American Manganese conducted a limited diamond-drill program near one of the Highland Boy adits in 2007.
In 2011, American Manganese Inc. carried out a program that entailed 22 kilometres of ground magnetometer survey, 841 soil samples, 455 rock samples and 68 silt samples. The most significant soil sample returned 8650 parts per billion gold, 72.4 parts per million silver, 0.58 per cent copper, 1.31 per cent arsenic and 20.09 per cent iron (V STOCKWATCH, November 20, 2012; Assessment Report 33297). At this time, the Rocher Deboule property covered three small, past-producing mines and five significant prospects including: Highland Boy (093M 070), Rocher Deboule (093M 071), Victoria (093M 072), Great Ohio (093M069), Cap (093M073), Golden Wonder (093M074), Three Hills (093M075) and Daley West (093M053).
Prospecting programs carried out were designed to step away from the known mines and expand the working knowledge of the property. Prospecting resulted in the discovery of numerous new showings. The principal areas of interest extend in an East – West trending belt from Golden Wonder (considerably west of the contact of the stock) through the Rocher Deboule and Victoria mines and east to the Highland Boy. One of the most intensely studied areas is the upper Silvertip Creek, approximately mid-way between the Rocher and Highland Boy mines.
On the Rocher Deboule occurrence itself, the 2011 program explored for extensions and additional structures of known veins. It focused on the potential for broader zones of lower-grade mineralization. New veins were found and pockets of alteration were noted and sampled. Fourteen samples were collected in the general vicinity of the old mine.