The exact location of the Last Chance showing is not known but it is mapped north of Sheppard Creek and approximately 3 kilometres north-northwest of Waneta at the junction of the Columbia and Pend-D’Oreille rivers.
The area is underlain by altered siltstone, hornfelsed siltstone, schist and basaltic volcanic rocks of the Lower Jurassic Elise Formation (Rossland Group) that have been intruded by granitic rocks of the Middle Eocene Sheppard Intrusion.
Locally, two veins, referred to as the No. 1 and No. 2 veins, host mineralization. The veins strike northwest and dip steeply to the southwest, probably parallel to the schistosity in the meta-sediment hostrock. The hostrocks are crosscut by a major north-trending aplite dike, related to the Middle Eocene Sheppard syenite intrusion.
The No. 2 vein ranges from 23 to 56 centimetres in width and hosts streaks and lenses of sulphides consisting primarily of chalcopyrite, with minor bornite in a gangue of altered country rock, quartz and calcite. The No. 1 vein, paralleling the No. 2 vein approximately 37 metres distant, hosts galena, sphalerite and pyrite with minor chalcopyrite in similar gangue. The No. 1 vein is approximately 91 centimetres wide and hosts semi-massive to massive- sulphide mineralization up to 18 centimetres wide. Both veins follow well-defined planes of fissuring and appear to be persistently horizontal.
In 1928, a grab sample from ore obtained from the No. 2 vein assayed 0.69 gram per tonne gold, 260.6 grams per tonne silver and 3.68 per cent copper, whereas a selected ore sample from an opencut on the No. 1 vein assayed 0.69 gram per tonne gold, 510.8 grams per tonne silver, 15.3 per cent lead and 5.4 per cent zinc and a grab sample from an ore pile from the No. 1 vein assayed 0.34 gram per tonne gold, 246.9 grams per tonne silver, 6.3 per cent lead, 11.6 per cent zinc and 1.92 per cent copper (Minister of Mines Annual Report 1928, page 356).
In 1988, Tobex Resources completed a program of geochemical sampling and a 113.0 line-kilometre airborne geophysical survey on the surrounding area as the AD 1-15 claims.
