Determination of Background Gold Content of Non-mineralized Outcrops in the Val d'Or Area: The Effects of Sampling

Exploration & Mining Geology, Vol. 1, No. 3, 1992

TYSON BIRKETT Quebec Geoscience Centre Quebec, Canada, FRANCOIS ROBERT, DAN RICHARDSON and STEVE GREEN Geological Survey of Canada, Ottawa, Ontario, Canada

Detailed sampling using a portable diamond drill, and interlaboratory comparison of selected samples have been combined with statistical studies of truncated populations to establish the gold content of several outcrops in the Val d'Or area. The outcrops chosen are non-mineralized. The background gold concentration in the rocks of the region is 5 ppb or less. Gold is distributed relatively homogeneously within the outcrops studied except for slightly increased concentrations within quartz-tourmaline veinlets. Three samples, of which 20 grams of powder are analyzed for each, can adequately determine the gold concentration of a structurally simple outcrop in the Val d'Or area.