The principal Granduc copper ore-bodies are contained within 64 Crown-granted and 180 recorded mineral claims covering an area of more than 19 square miles. Records indicate that the first claims staked in the area of the Leduc River were recorded in 1931 by Wendell Dawson and W. Fromholz of Ketchikan, Alaska, following a prospecting trip up the river to its source. The claims were allowed to lapse.

 Base camp a the Granduc MineClaims had been staked on Unuk River, nine miles north of Granduc, as early as 1899, but there is no record that the prospectors of that day followed the Unuk Glacier to its source at what is now known as Granduc Mountain. It is even probable, geological analysts say, that in 1900 the lower Granduc showings were concealed by glacier ice which, fortunately, is decreasing in elevation at the rate of about 10 feet per year.

In 1951, two well-known B. C. prospectors, Einar Kvale and Thomas McQuillan, employed by the Karl Springer and associated interests in the name of Helicopter Exploration Co. Ltd., staked the claims covering the outcrops and adjoining areas. Preliminary exploration indicated a copper deposit of some magnitude and importance.

The following year, the property was optioned to The Granby Consolidated Mining, Smelting and Power Company Limited, since renamed The Granby Mining Company Limited. Examination of the claims was followed by surface and underground exploration in 1953 when Newmont Mining Corporation first joined to continue the underground work. A mining plant, diamond drills, and other equipment were air-lifted to the property and a camp was established. Results were encouraging and an extended programme was carried out during the succeeding years.