sui ility mining sand as aggregate
sui ility mining sand as aggregate. CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1928 USGS. PLATINUM AND BLACK SAND IN WASHINGTON 5 gravel and sand from 1 to 3 feet thick and is strewn with cobbles at the base of the cliff. The metal-bearing part of this deposit is a thin layer of fine, heavy sand, composed chiefly of pink garnet and black ...