Excerpt from A Comprehensive Reference Book on Practical Coal Mining My mining experiences began at the age of eight years, in the pits of the Midland district, and since that age I have been constantly engaged in different capacities in mining operations. It is obvious, therefore, that this work can make no pretensions to literary excellence, but it is offered as a practical reference book on mining, written by a practical man. In preparing this edition I have received valuable and willing assistance from mining and mechanical engineers of experience and standing, and, in order to make the work complete, I have not hesitated to quote freely from eminent writers on the most important mining topics. Thanks are also due to several engineering firms for the loan of drawings, &c., of specialities manufactured by them, which it is hoped will add to the completeness of the book, and of which acknowledgment will be found in the text. 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.