The Chalco property is located on the western edge of the Late Triassic-Early Jurassic Guichon Creek batholith and occurs entirely within a speckled grey-green and black quartz diorite of the Hybrid phase of the batholith. Steep east to southeast-striking faults are evident along Pukaist Creek and commonly host copper mineralization.

Chalcopyrite occurs in veins with quartz, chlorite, amphibole, calcite, magnetite and epidote. Bornite has also been reported. Chalcopyrite may also occur in veins with one or more of these components missing or in veins containing pyrite and/or hematite. Most of the chalcopyrite-magnetite bearing veins occur in easterly striking fault zones. Veins intersected in diamond-drill holes were commonly less than 3 centimetres wide and 1 to 3 metres apart. Near the old workings, major faults with gouge zones up to 12 metres wide but typically near 3 metres, occur approximately every 38 metres. Many faults do not contain chalcopyrite mineralization but in those which do, veined zones are commonly 0.9 to 1.2 metres wide and locally range up to 3.6 metres wide.

Within fault zones, mineralized veins were observed to branch off a major fault, follow a secondary shear across the gouge zone, then follow a second major fault. Post-mineralization subhorizontal faults occur which offset the steep easterly striking faults. Where it could be determined, dipslip movement was less than 15 metres (Geology, Exploration and Mining in British Columbia 1970).

In 1958, New Hamil Silver-Lead Mines Limited conducted a magnetometer survey on the Tofin group of claims which cover the showing area along Pukaist Creek. Troy Silver Mines Ltd. put down seven diamond-drill holes to test mineralization exposed by road building and targets delineated by a ground magnetometer survey done in 1969. Troy Silver Mines Ltd. also conducted a soil geochemical survey in 1969. In 1975, percussion drilling of five holes totalling 159 metres was conducted on the L & L claims covering the Chalco showing on behalf of L.W. Reaugh.

Old workings consist of a 122-metre adit driven easterly on a shear zone at the Pukaist Creek level. Across the creek a shorter tunnel has been driven on the same zone. Several small pits have been excavated on similar weakly mineralized veins on the east side of Pukaist canyon.