The area of the Falu occurrence is underlain by rocks of the Pennsylvanian, and possibly Permian, Mount Roberts Formation which may be correlative with the Milford Group farther north. The Mount Roberts rocks are comprised of siliceous siltstone, argillite, silty chert, limestone or dolomite and minor sandstone and greenstone. The contact of the Bonnington pluton of the Middle to Late Jurassic Nelson Intrusions occurs within a few hundred metres to the east.

A shaft sunk 21 metres on the hanging wall, from which a crosscut struck the footwall in 6 metres, shows a body of ore reported to assay 64 to 80 grams per tonne gold (Hodges, 1897).