Comparison between analytical and mineralometric methods in regional scheelite exploration

The scheelite dispersion was studied in a drainage system over an area of 150 km² with stratabound mineralization of scheelite in a Pre-Ordovician volcano-sedimentary Series in the Hercynian Iberian Massif (Zamora province, NW Spain). A density of two samples per square kilometer (approximately 500 m sample spacing along streams), a sample volume of 10 l and sieving at 5 mm ensure that an anomaly source is detected. It was found that the dispersion of scheelite is typically less than 1 km. The methods applied to panned concentrates (mineralometric scheelite study, with or without multifractional grain size basis, and X-ray fluorescence tungsten analysis) give similar anomaly patterns and are efficient in exploration for scheelite mineralization.