The Pioneer Extension property lies between Noel and Chism Creeks, along the southwest side of Cadwallader Creek, in the Pacific Coast Range. In this part of the Coast Crystalline tectonic belt, extensive splays and cross faults of the Bralorne fault system are spatially related to numerous mineral occurrences in the Bridge River mining camp. Mississippian to Jurassic Bridge River Group cherts are faulted against greenstone of the Pioneer Formation and metasedimentary rocks of the Hurley and Noel formations, all of the Upper Triassic Cadwallader Group. Dykes and stocks of augite-diorite and soda-granite of the Bralorne Igneous Complex, serpentinized peridotite of the President Ultramafics (correlative with the Permian and older Shulaps Ultramafic Complex) and late hornblende and feldspar porphyry dykes are emplaced concordant to the principal formations, following the trend of the main faults.

Talc occurs as an alteration phase within serpentinite. A shaft penetrates 30 metres of talcose rocks continuing exotic blocks of chert and argillite and intruded by albitic dikes.

Banded, discontinuous quartz veins occur in two sets striking northwest and northeast, following fractures in the competent greenstones and crystalline plutonic rocks. Principal production came from 4 large veins, the 77, 51, 21 and the main vein. The main vein strikes due east, dips shallowly north and averages 1.2 to 2.0 metres wide, over a strike length ranging from 1000 to 1500 metres. The vein extends down-dip for 1500 to 2000 metres. The veins consist of white quartz with small amounts of sericite, chlorite, ankerite, calcite, very minor pyrite and arsenopyrite and rare free gold.

The veins have a banded structure and sharply defined walls. Envelopes of hydrothermal carbonate alteration up to 70 metres wide accompany and appear to slightly postdate many of the quartz veins. The downdip extension of the most significant veins was tested by diamond-drill hole P85-02 in 1985 and intersected 2 quartz veins, 1.0 meter and 1.5 metre wide. Assays ranged from trace to 2.74 grams per tonne gold (Assessment Report 15730).