The TOT 2 showing area, northwest of Tatsamenie Lake, is mainly underlain by Mississippian tuffs, phyllites, siltstones and limestone of the Stikine Assemblage. These rocks are intruded by plutonic rocks associated with three separate igneous events. These consist of foliated quartz diorite of Middle to Late Triassic age, unfoliated diorite of Jurassic age, and feldspar porphyry basaltic dikes of the Paleocene to Eocene Sloko-Hyder Plutonic Suite. The volcanics and sediments have undergone two phases of folding, a tight isoclinal fold with a horizontal fold axis and an upright more open fold.
The Permian limestones are a dark grey, thin bedded, grey weathering carbonaceous unit. The overlying phyllites contain interbedded siliceous siltstone and buff weathering limestone. These are overlain by intermediate to mafic volcanics, some of which have been metamorphosed to chlorite schist.
A 5 to 10-centimetre chalcopyrite vein occurs within the chlorite schist. A sample assayed over 1.0 per cent copper and 14.8 grams per tonne silver (Assessment Report 11779). Stibnite and barite veins also occur in this area (GSC Map 1262A). In 1992, field crew of BC Geological Survey Branch mapped and sampled the area, mostly south of Tatsamenie Lake. One sample taken several hundred of the TOT 2 was described as quartz-iron carbonated mafic volcanic rock. The assay was not significant.
Mineral exploration in the Tatsa property area began in the 1960s when companies were first drawn to the large alteration zone that extends along the north shore of Tatsamenie Lake looking for porphyry copper mineralization (Walton, 1987). This continued up to 1977 when Mattagami Lake Mines located the TOT 2 copper-silver-antimony and MB copper occurrences (MINFILE 104K 037, 104K 041; Assessment report 7610). Drilling was reportedly undertaken on the MB occurrence.
In addition to Chevron's work south of Tatsamenie Lake in the early 1980s (see LCZ (104K 080) and Extension (104K 137)), Chevron conducted geological mapping, trenching, and soil and rock geochemical sampling and drilling over a large area that included the TOT and TOT 2 copper and copper-antimony occurrences located on the Tot 1-4 claims (later the Tatsa property of Solomon Resources) (MINFILE 104K 098; Assessment Reports 11779, 13068, 16528). Trenching work on the TOT identified a north trending shear zone hosting of pyrite, chalcopyrite, stibnite and scorodite mineralization that assayed 3.4 grams per tonne gold over 2.42 metres (Assessment report 13068)
In the early 1980's, Chevron Canada Limited began a precious metal reconnaissance program in the region that ultimately lead to discovery of the Golden Bear mine to the south (Figure 1). After initial discovery of the Bear Main deposit in 1984, the majority of the Chevron work was focused south of Tatsamenie Lake along the major north trending Ophir Fault. In addition to this work, Chevron conducted geological mapping, trenching, and soil and rock geochemical sampling and drilling over a large are that included the TOT and TOT 2 copper and copper-antimony occurrences located on the Tatsa property (MINFILE 104K 098). Trenching work on the TOT identified a north trending shear zone hosting of pyrite, chalcopyrite, stibnite and scorodite mineralization that assayed 3.4 grams per tonne gold over 2.42 metres. Chevron drilled a single drill hole in 1987 on the TOT intersecting 3.81 grams per tonne gold over 2.26 metres (Assessment Report 16538, 16726).
Solomon Resources Limited staked the Tatsa claims in early 2004 which covered much of the same ground as earlier Tot 1-4 of Chevron. Solomon personnel spent a total of 29.5 person-days on the property. The 2004 work included geological mapping, prospecting and reconnaissance soil and silt geochemical surveys. A total of 49 rock (34 grab, 4 chip and 11 float samples), 571 soil and 13 stream silt samples were collected and submitted for geochemical analysis during the exploration program. The Tatsa property is host to only four known in situ mineral occurrences. These include the TOT, TOT 2, MB and the Tatsa discovered in 2004 by Solomon. The results from the 2004 Tatsa property work program did not identify any obvious mineral target areas. However, three areas with moderate soil anomalies were outlined and reported to warrant further investigation.
Refer to TOT (104K 098) for details of a common geology and work history. Also refer to LCZ (104K 080) and Extension (104K 137) for details of a common geology and work history prior to 2004.