Excerpt from United States Census of Mineral Industries, 1954, Vol. 2: Area Statistics, Industry Statistics for Geographic Divisions, States, and Counties Mining Operations were classified by industry, on the' basis of the principal mineral produced or, if there was no produc tion, on the basis of'the principal mineral for which explora tion or development work was in process. The recovery of material from culm banks, ore dumps, and other waste min erals piles was classified with the appropriate mining industry according to the mineral product recovered. Mineral preparation plants are usually operated together with mines or quarries and frequently no separate records for them are maintained. All such preparation plants are included in the scope of the minerals census. In general, separately operated preparation plants, whether they process minerals for the account of the operator or on a custom or toll basis for others, are also included in the minerals census. Coal cleaning and sizing plants Operated at mines or as separate establish ments are so included. However, the crushing, grinding, or otherwise treating of certain nonmetallic minerals (except fuels) About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.