The MAD occurrence (104K 028) is located about 6.4 kilometres south of King Salmon Lake, north of the Sutlahine River.
The area is underlain by the Lower to Middle Jurassic Laberge Group rocks of the Takwahoni Formation. These rocks are comprised of well-bedded greywacke, graded siltstone, sandstone, mudstone, and pebble conglomerate. The Takwahoni Formation trends northwest to northeast, exhibits two stages of folding, and is faulted in a number of locations in a general east-west direction.
The Takwahoni sediments are crosscut by numerous felsite and quartz-feldspar porphyry dikes and sills of Late Cretaceous to Lower Tertiary Age. These intrusions are thought to be genetically related to the Sloko Group volcanics (GSC Map 1262A).
A hydrothermal zone containing considerable pyrite mineralization is associated with the intrusions. As well, considerable silicification-pyritization and clay alteration accompanies the emplacement of these intrusives.
Northeast trending faults and narrow shears are often characterized by bright gossans with considerable magnetite and limonite staining. These are spatially related to the felsite dyke alteration zones. In 1970, minor copper mineralization was reported within narrow shears in or adjacent to the intrusive rocks. Mineralization consisted of disseminated pyrite, chalcopyrite, and malachite.
Work History
In 1970, a geologic mapping program was carried out on the BS, Mad, Nut and J historic claim groups by the Taku Syndicate. Copper and molybdenite mineralization were found to be associated with northeast-trending faults and joints systems in a quartz-monzonite host. Although the mineralization was widespread based upon mapping and ground magnetic response, geochemical sampling failed to indicate an economic concentration.
In 1986, Noranda Exploration Company conducted prospecting, geological mapping and geochemical sampling on the KS claim group. A total of 14 silt, 12 talus fines, 22 rock and 4 panned concentrate samples were collected. Rock samples were collected from silicified zones within the hornfels sediments (Assessment Report 15477). One sample from a silicified zone assayed 0.04 grams per tonne gold, 13.2 grams per tonne silver, 1.32 per cent lead, 0.041 per cent zinc, 0.023 per cent copper, and 0.004 per cent arsenic. Another sample assayed 0.06 grams per tonne gold, 2.0 grams per tonne silver, 0.102 per cent lead, 0.04 per cent zinc, 0.023 per cent copper, and 0.102 per cent arsenic. The gold values ranged from 0.04 to 0.07 grams per tonne with the highest assay being associated with 0.62 per cent arsenic.
In 1990, Solomon Resources Ltd. conducted work on their King claims, a portion of which covered the Mad area. Reconnaissance geological mapping and geochemical sampling of three gossan zones, designated A, B and C, confirmed that the gossans were caused by pervasive disseminated pyrite within silicified Sloko Group granodiorite and Stuhini Group volcanics. Zone C is the same area where the original Mad and KS work was conducted in 1970 and 1986. Rare lenses of recrystallized carbonate epidote skarns were found to be associated with pelitic rocks, also referred as ferruginous hornfels. Hornblende granodiorite intrusion is exposed within the hornfels. Pyrite and lesser pyrrhotite are disseminated in these intrusive rocks. Associated with the more leucocratic varieties of these rocks are disseminated molybdenite flakes, less than 1 mm in diameter.
Quartz-carbonate veins are located within the west-flowing creek at the extreme western end of the map area (Assessment Report 21530, Map 2). They are 3 in total, and they are mineralized with patchy zones of galena, chalcopyrite, and stained with malachite and azurite. They average 15 cm in width. Two of them can be traced for 20 metres. The third vein is 10 cm wide, and occurs 100 metres down stream along the strike of the first two veins. All these veins are associated with east-west trending, steeply dipping shear zones averaging 30 cm wide. Samples yielded up to 131.9 grams per tonne silver (Assessment Report 21530).
During June 2004, Rimfire initiated a regional geological mapping, prospecting and soil and silt sampling program on the LJ and Sutlahine claims, collecting 85 rock samples, 92 silt samples and 504 soil samples (Assessment Report 27589). A 0.20-metre chip sample (276528) of chalcedonic vein breccia assayed 13.35 grams per tonne gold, 324 grams per tonne silver, 0.522 per cent lead and 0.340 per cent zinc, while other chip samples of chalcedonic vein breccia, varying from 0.1 to 0.5 metre in length, yielded values of up to 2.53 grams per tonne gold, 1255 grams per tonne silver, 0.146 per cent copper, 1.09 per cent lead and 5.07 per cent zinc (Baker, D. (2010-10-28): 2010 Technical Report on the Thorn Property). Also at this time, a grab sample (276527) of weakly silicified sandstone with 1 to 3 per cent pyrite assayed 1.31 grams per tonne gold (Baker, D. (2010-10-28): 2010 Technical Report on the Thorn Property).
In 2005, Barrick Gold Incorporated explored its large Kizmet claim holdings (including the Sutlahine claims of Rimfire Minerals) that extended from Tatsamenie Lake northwest to the Taku River. The property covered a 70 by 20 km area. Barrick collected 848 rock, 46 stream sediment and 31 soil samples. Work was done in the Mad area under the “Sut” designation. Results from the overall field season were considered to be poor.
In 2017, the area of the Mad showing was held by Brixton Metals Corporation as part of their Thorn property, at which time they ran reconnaissance soil lines along the mountain ridges to the immediate north and east of the Mad MINFILE plot. The most anomolous soil sample was located about 560 metres to the north of the Mad, grading 25.8 grams per tonne silver, 0.15 grams per tonne gold and 0.89 per cent copper (Assessment Report 36829).
In 2020, Brixton Metals Corporation completed a program of geochemical (rock and soil) sampling, a 12.5 line-kilometre ground induced polarization survey, a 715 line-kilometre airborne magnetic and electromagnetic survey and 19 diamond drill holes, totalling 5292 metres, on a part of the Thorn property. Drilling was performed on the Outlaw (MINFILE 104K 176) occurrence area.
See Thorn (104K 031) for further information on the Thorn property.
