ISBN: 1177604000 / ISBN-13: 9781177604000
Steam Shovel Mining; Including a Consideration of Electric Shovels and Other Power Excavators in Open-Pit Mining
by Robert Marsh
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from ... Show synopsis 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. 1920 Excerpt: ...the higher the banks, i.e., the greater the vertical distance that can be allowed between benches, the more economical will become the removal of overburden, and the more efficient the shovel operation. There will be a smaller total yardage of overburden to remove because less horizontal area will have to be exposed to allow for the area of the benches eliminated. In other words, a steeper average slope from crest to toe of stripping can be realized. With deep or steeply dipping deposits the volume of slope yardage may become formidable. Reference to Fig. 2, in Chapter I. will illustrate this. Also the shovel operation will be more efficient because there will be less time consumed in moving the shovel ahead, and it can work in one spot, so that its loading time may be correspondingly increased. In practise, however, the height of banks should be kept down to reasonably safe working conditions. It may furthermore be desirable to provide additional benches so that there will be plenty of working faces, or separate faces as natural divisions between different classes of ore or between ore and waste. Consideration of trackage arrangements may also require a reduction in bank heights because in running from bench to bench the gradients must be kept reasonable. The total rise possible is the product of the grade by the allowable length of track. The problem is thus a compromise between theoretical economy and practical conditions, but there are reasonable limits in both cases. Benches less than 12 feet high are not economical, from the standpoint of shovel operation, because there is too much time spent in moving ahead; and benches over 75 feet high are liable to be difficult to control. Most work can be carried on somewhere within this range..In the anthracite ...