KeywordsArizona Geological Survey Bulletins
United States of America
MetadataShow full item record
PublisherUniversity of Arizona Bureau of Mines
DescriptionOne of the first and most important matters which has to be determined in connection with a mining property, after it has been decided to develop it, is the class of entry which is to be used in opening it up. At this stage in the development, the factors governing the choice, providing sufficient capital is available, are based principally lipan the amount of definite knowledge which can be brought to bear to determine the value and possibilities of the deposit. If the size, values, strike, dip, etc., of the deposit are reasonably well known and the deposit is valuable, the choice of entry is then decided so that all work expended is of a permanent nature, and will fit in with the plan of development as determined at that time. If, on the other hand, the property is a prospect, such as an outcrop deposit in a section where no mines have ever been developed, and where the principal objects are to expose the ore and find out as much as possible concerning the size of the ore bodies, their locations, dips, strikes, values, metallurgical characteristics, etc., and no one on the job knows definitely what can be expected when the property is opened up at depth, the common and sane practice, in most cases, is to follow the ore by using one or more inclines. After they have accomplished the purpose for which they are intended and the ore body has been found to be valuable, these inclines can then be used either in the operations of the mine as a part of the permanent entries, which are to be constructed, as escape ways, for ventilation purposes, or, if of no further use, they can be abandoned. When abandoned, the expenditure should not be looked upon as having been wasted, because they have served their purpose, and if, by their use, the value of the deposit has been found, the money spent will represent only a very small part of the cost of the permanent equipment which will be installed, or the revenue which the mine will produce if properly handled.15 p.
Series/Report no.Bulletin No. 82
Economic Series No. 17