Limestone is mined underground on the north side of Lost Creek, 2.85 kilometres northeast of its confluence with the South Salmo River.

The mine is developed in limestone of the Reeves Member of the Lower Cambrian Laib Formation. The unit strikes 060 degrees and dips 45 degrees southeast.

The deposit consists mostly of massive, sugary textured, fine- grained (1 millimetre), white limestone mottled in places with a slight yellow colour. Zones of light to dark grey banded limestone, occasionally with rusty streaks, were encountered in the mine. A sample of fresh fragments contained 52.8 per cent CaO, 0.82 per cent MgO, 1.31 per cent SiO2, 1.29 per cent Al2O3, 0.15 per cent Fe2O3, 0.055 per cent MnO, 0.02 per cent TiO2 and 43.25 per cent ignition loss (Geological Fieldwork 1985, page 240). The ground limestone is reported to have a brightness of 94.85 per cent.

Limestone has been mined here by International Marble & Stone Company since late 1983 after abandoning the quarry on Swift Creek (082FSW215). Between 1984 and 1987, 26,379 tonnes of limestone were mined by IMASCO. The limestone is trucked to Sirdar where it is crushed and ground for a variety of products, including filler applications.