From the site: "MRDS is a collection of reports describing metallic and nonmetallic mineral resources throughout the world. Included are deposit name, location, commodity, deposit description, geologic characteristics, production, reserves, resources, and references. It subsumes the original MRDS and MAS/MILS.

MRDS is large and complex. This service provides a subset of the database comprised of those data fields deemed most useful and which most frequently contain some information, but full reports of most records are available as well."