Excerpt from The Methods of the United States Steel Corporation: For the Commercial Sampling and Analysis of Coal, Coke and by-Products Most coals occur in horizontal layers and also in vertical laminations, and; when coal is being mined so that the face of the laminations is exposed, it is described as being on the face; when exposing the ends, it is described as being on the butt. A face or butt sample is taken mainly for information relative to Operating purposes. Channel samples should be taken preferably on the butt, for the reason that it is easier to cut a true channel there. 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.