An attempt at assessment of mineral resources

Abstract

Mineralization factor (f) is defined here as a ratio (r/t) of the amount of an element (r ton) concentrated as the mineral deposits in a definite volume (or mass) of crust to the total amount of the element (t ton) in the crust. The factors of some metallic elements were tentatively calculated for selected areas including Japanese Islands and North American continent using published data on the reserves or resources of the elements. The factors vary to some extent in different regions and for different elements, but, generally speaking, are in order of 10 ^-4 to 10 ^--5 in Japanese Islands and 10 ^-5 to 10 ^-7 in North American continent for most of the metallic elements (Fig. 1 and Tab. 3). If it is justified to assume the general mineralization factor (F) for all the metallic elements concerned in the upper continental crust to be 10 ^-4-4 to 10 ^-5 based on the existing data, the total amount of the specific metallic element (R ton) concentrated in the mineral deposits of the upper continental crust is given by the following equation: R=M×n×A×10^-6×F, where M is total mass (ton) of the continental crust, n estimated ratio of mass of upper continental crust where mining operations are assumed in future to total mass of the continental crust (here assumed to be 0.2 or 0.3, which corresponds to about 7 to 10km in depth from the surface), A crustal abundance of the element (ppm) in the continental crust, and F general mineralization factor in the upper continental crust. Table 5 and Figure 3 show the results obtained. Some considerations on the results are also given.