What are Proven Reserves?

Proven reserves are those reserves for which the quantity has been computed from the dimensions indicated in outcrops, trenches, drill holes and so forth, while the grade is computed from the results of detailed sampling. In addition, the sampling sites are spaced so close together that the size, shape, depth, and mineral content of reserves can be established. The amount of reported proven reserves can suddenly change, due to variations in the available level of technology, market conditions, and regulatory requirements. These reserve figures are derived with the engineering and geological data that has been collected from exploratory drilling and seismic testing.

A mining company can reasonably expect to extract the reported amount of proven reserves.