The Ace in the Hole showing is situated south of Archibald Creek, west of the Salmo River and approximately 7 kilometres southwest of Salmo.
The area is underlain mainly by basaltic volcanics of the Lower Jurassic Rossland Group, Elise Formation, composed of flow breccia, massive flows, agglomerate, tuff and sill-like intrusives (augite porphyry). A minor amount of laminated, tuffaceous siltstone and shale occur as interbeds. These are overlain by argillites and quartzites of the Rossland Group, Hall Formation and are underlain by black argillaceous siltstone and arenaceous argillite of the Rossland Group, Archibald Formation. The Rossland Group rocks are intruded by the Middle to Late Jurassic Nelson intrusions, which are composed of a rock ranging in composition from granite to quartz diorite.
The Ace in the Hole occurrence is underlain by two interbedded, mafic volcanics of variable thickness. The lower unit consists of a framework-supported, poorly sorted volcanic breccia. The other volcanic unit is a matrix-supported mafic crystal tuff with abundant pyroxene and plagioclase crystals. A small body of rhyolite measuring approximately 700 metres from north to south with a maximum width of approximately 200 metres is exposed on the Ace in the Hole claim. The distinctive quartz porphyritic rhyolite is of uniform composition and contains flow banding throughout. Thick pyritic chert sequences containing pyrite laminae and ash beds also occur along with sedimentary units including argillite mixed with ash, fine-grained greywacke and quartzite interbeds. Disseminated pyrite is common throughout the rocks on the property.
Mineralization occurs within quartz-carbonate vein systems running roughly east to west across the property. An historic shaft was sunk to access a sulphide-bearing narrow quartz vein that pinched and swelled to a maximum width of approximately 40 centimetres.
Several collapsed trenches and pits located near or at the Ace in the Hole occurrence are believed to date back to the early 1900s and likely record the earliest exploration history on the Swift Katie property. In 1985, Falconbridge Limited noted the existence of a small adit with a 5-metre-deep shaft.
In 1984, Falconbridge Limited sampled one small soil sample grid on the Ace in the Hole claims. In 1987, Falconbridge Ltd. completed 31 trenches totalling 1730 metres in length on the Swift-Gus (MINFILE 082FSW291) and Ace in the Hole claims. The trenches were mapped and a total of 463 channel and grab samples were collected and sent for analysis. Seven trenches (trenches 25 to 31) were completed on the Ace in the Hole claims.
In 2005, the Katie claim group (MINFILE 082FSW290), owned by John A. Chapman and KGE Management Limited, was merged with the Swift (MINFILE 082FSW291) and Ace in the Hole claim groups to form the Swift Katie property.
In 2006, Valterra Resource Corporation optioned the Swift Katie property. The following year, Valterra compiled historical data, added additional claims and completed an exploration program of reconnaissance mapping and diamond drilling. In late 2007 and early 2008, Valterra contracted Fugro Airborne Surveys Corporation to complete 505 line kilometres of airborne geophysical surveying over most of the Swift Katie property. In 2008, Valterra conducted prospecting over the property. In July 2007, on behalf of Valterra Resource Corporation, Micon International Limited released a National Instrument 43-101 resource report for the property. The following year, the property was optioned to Tosca Mining Corporation.
In 2011, Valterra Resource Corporation completed historical and recent diamond drill collar location, identification, marking and surveying, commissioning Eagle Mapping Limited to complete a 1:2500 scale digital map of the main mineralized zone. By the end of 2011, Valterra Resource Corporation had earned a 100 per cent interest in the Swift Katie property.
An old 5-metre deep shaft was sunk on a narrow quartz vein that pinched and swelled to a maximum of 0.4 metres. A sample of a sulphide-rich pocket graded 0.75 gram per tonne gold, 132 grams per tonne silver, 0.99 per cent copper, 4.65 per cent lead and 0.12 per cent zinc (Assessment Report 14934, page 15). Sulphides included pyrite, chalcopyrite, galena and sphalerite. A trench was later excavated from the shaft (Trench 27) within mafic volcaniclastic country rock.
In 1987, a 2-metre channel sample from Trench 30 returned 1.75 grams per tonne gold, and an adjacent grab sample returned 1.65 grams per tonne gold (Assessment Report 16901, page 17).