The Invincible orebody is adjacent to the western margin of the Dodger stock of the Middle to Late Jurassic Nelson Intrusions where it transects flat-lying beds of the Reeves Member limestone of the Lower Cambrian Laib Formation. The tungsten ore zone lies northward and along strike, but on the east side of the Granite fault, from the Feeney (082FSW247) and Emerald (82FSW010) deposits.
The orebody occurs on the overturned limb of the Jersey anticline and is bounded above and below by skarn and argillite of the Truman and Emerald members of the Laib Formation respectively. Most of the scheelite occurs in lenticular zones that extend at a high angle from the granitic stock, more or less conformable with layering of the marble. The scheelite occurs as fine, disseminated grains within garnet-diopside skarn and is accompanied by pyrite, pyrrhotite, minor powellite and traces of molybdenite and wolframite. Quartz is common in zones of mineralized granite.
The ore zone extends up to 24 metres from the stock, and may be more than 3 metres thick in places. The zone lies about 260 metres below surface and produced 256,480 tonnes of 0.65 per cent WO3 from 1970 to 1973 (Geology, Exploration and Mining in British Columbia 1973, pages 54-57). Production is included with the Emerald Tungsten mine (082FSW010) and recorded with the production statistics of the Jersey mine (082FSW009).
Ore Reserves calculated by Canadian Exploration Ltd. (Canex) in August 1973 estimated that the Invincible Tungsten Mine contains a combined probable, possible and marginal ore reserve of 68,141 tonnes grading 0.62% WO3 (Boronowski, 2001). This represents approximately 335,089 kilograms (738,748 pounds) of tungsten.
The majority of the reserves are reported to be accessible from the underground workings. As of 2001, the northern extension of the Invincible mine remained untested.
In 2005, Sultan Minerals Inc. completed 20 underground drill holes, totalling 6859.6 metres, and two surface drill holes on the Dodger Tungsten mine workings, particularly the Dodger 4200 zone. In 2006, eight diamond drill holes, totalling 1016 metres, were completed on the East Emerald Tungsten zone, also referred to as the Dodger “D” zone. In 2007, a further 19 underground drill holes, totalling 3886 metres, were completed on the East Dodger molybdenite zone and 61 surface drill holes, totalling 9147 metres, were completed on the property. During 2008 through 2010, programs of soil sampling and airborne geophysical surveys were completed on the property. In 2014, Margaux Resources Ltd. completed 35 diamond drill holes, totalling 6,318.6 metres, on the East Emerald zone.
In 2006, Sultan Minerals Inc. reported an updated tungsten resource for the Dodger and Invincible deposits of 2.277 million tonnes measured and indicated grading 0.37 per cent tungsten tri-oxide with an additional 1.098 million tonnes inferred grading 0.40 per cent tungsten tri-oxide, using a 0.15 per cent tungsten tri-oxide cut-off grade (Cowle, S. (2007-05-23): Technical Report on the Jersey Emerald Property, British Columbia).
In 2008, Sultan Minerals Inc. reported a combined resource for the Invincible, Dodger, East Emerald and Emerald mines tungsten zones was reported at 2.509 million tonnes measured and indicated grading 0.36 per cent tungsten tri-oxide and 2.204 million tonnes inferred grading 0.34 per cent tungsten tri-oxide, using a 0.15 per cent tungsten tri-oxide cut-off grade Giroux, G.H. (2014-03-28): Technical Report for the Jersey-Emerald Property).
In 2015, Margaux Resources reported a combined resource for the Invincible, Dodger, East Emerald and Emerald mines tungsten zones was reported at 2.786 million tonnes measured and indicated grading 0.341 per cent tungsten tri-oxide and 4.971 million tonnes inferred grading 0.273 per cent tungsten tri-oxide, using a 0.15 per cent tungsten tri-oxide cut-off grade (Park, V. (2015-03-15): Technical Report for the Tungsten Resource Update of the Jersey-Emerald Property).
In 2016 and 2017, Margaux Resources completed programs of ground geophysical surveys and diamond drilling, totalling 1997 metres in 12 holes, on the area. Further drilling was reported to have been completed in 2018.
In July 2021, an updated openpit and underground mineral resource for the Jersey-Emerald project was reported at 1 472 803 tonnes indicated grading 0.173 per cent tungsten tri-oxide, 0.021 per cent molybdenum and 0.050 gram per tonne gold with an additional 5 128 045 tonnes inferred grading 0.227 per cent tungsten tri-oxide, 0.026 per cent molybdenum and 0.081 gram per tonne gold (Moose Mountain Technical Services [2021-07-26]: NI 43-101 Resource Estimate for the Jersey-Emerald Project).
