| Description |
vi, 107 leaves : illustrations, photographs ; 29 cm |
| Summary |
"A decided change in the attitudes of mining management toward the need for mine research has taken place during the past decade. More emphasis is being placed not only on the improvement of existing mining methods, but also on the adaptation of new ideas. As the depletion of the high grade ore deposits in this country becomes a reality, the need for reducing the costs of mining is pressing. The successful exploitation of low grade ore bodies will depend upon the continued advancement in the science of mining. The methods used today in driving a small drift or tunnel in rock have not varied much since the introduction of mechanization in the mining industry. Depending upon the conditions encountered and the types of equipment used, numerous small hole drill round patterns have been developed and successfully used. With the advent of new and better drilling and loading equipment, it has become apparent that present drill round patterns, with their limited depth, cannot fully utilize these advances in mining technology. The research work presented here is a study of the problems encountered in the designing of a drift round which uses a large diameter hole as part of the cut. The basic function of the large hole is to provide an effective second free face to which the cut holes can break. This large hole effectively increases the stress relief available to the cut holes and permits a much greater advance per round than the conventional small hole drill round patterns. The use of a large hole to provide a second free face for the cut holes is not necessarily limited to drift rounds, but could also be used, probably to better advantage, in large horizontal stopes"--Introduction, leaf 1. |
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