First Report of Progress in the Anthracite Coal Region; The Geology of the Panther Creek Basin or Eastern End of the Southern Field (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 Excerpt: ...at each colliery, were determined, by developing into a horizontal plane (as in the case of the entire surface of the Mammoth bed already explained) the surface area of the coal beds in the exploited areas. This would apply, especially, to those areas where the surface of the coal-bed is considerably contorted by flexures. The areas of the coal beds, under the smaller surface areas, where the dip of the beds is approximately the same throughout, were obtained directly by calculation without going through the more tedious method of a geometrical development. After the surface areas were measured, the areas of the surface of the coal-beds were determined, by dividing the former areas by the cosine of the angle of dip. As will be observed, from an inspection of the tables, estimates have been made, in most cases, between the main gangways driven at different levels at each colliery. This has been done, more particularly, in cases where the bed has been mined on comparatively steep dips, and where the coal has been taken from breasts worked from a lower gangway, which has been driven nearly level along the strike of the bed, 300' from an upper gangway; the measurement being made along the dip of the bed. It was necessary, in such cases, to determine the areas of the beds between these different gangways; this was done by measuring the distance apart of the gangways on the dip, along equidistant cross-sections at right angles to the strike of the bed. From these measurements, the average distance of the gangways apart was obtained, which being multiplied by the length of the area under discussion, gave the actual area of the surface of the coal bed between the different gangways. In all these estimates duplicate computations were made, independent of one another...