Publisher's Synopsis
Excerpt from Prospecting and Mining of Copper Ore at Santa Rita, New Mexico
It is a far cry from the small and uncertain mining efforts of 50 years ago to the splendidly equipped and solidly financed organiza tions that now handle thousands of tons of ore per day. The old mining was largely speculative; the new is practically on a manu facturing basis. In the' oldidays of mining the aim was, chie?y, to find comparatively rich ore; modern practice looks more toward efficiency in mining and milling, so that vast tonnages of low-grade material may be worked at a profit. The old operators had faith and hoped for good returns; the new ascertain with a fair degree of precision what the available tonnage is, what the cost of mining and treating the ore will be, the time necessary to exhaust the deposit, the capital required, and the net profits to be made. The old mining was financed on a highly speculative basis, and the value of mining stock was largely controlled by the imaginations of the promoters and of the individual holders. In the new régime the financing of mines is often as conservative as the financing of manufactures or railroads, and the value of stock, quoted on the leading exchanges, is controlled by the carefully estimated profits in sight. Of course, with every legitimate industrial enterprise go certain business risks, and mining is not exempted from these. Then, too, valueless mining as well as valueless industrial stocks are sometimes offered for sale by the intentionally dishonest, or the ignorant. However, the prospective purchaser of a mine nowadays, if he is willing to pay for the services of reputable mining engineers, can obtain information on which to base an opinion as to the quality of his investment.
The relatively recent development of cheap and efficient methods of mining and of ore dressing has given value to low-grade ore bodies that a few years. Ago were almost valueless. The iron mines of northern Minnesota have been fruitful in developing efficiency in mining methods, notably the open-cut methods in which steam shovels strip off the overburden and then load the ore directly into railroad trains for transport to the furnace. In 1907 open-lcut mining was applied to the low-grade copper ores of Bingham, Utah, with splendid results, and since then it has won a most important place in the min ing of large masses of low-grade ores in several other mining regions, especially at Santa Rita, N. Mex.
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