The trouble with the cited placers of South America is that climatic, hygienic and political conditions have been antagonistic to successful working: the ground is rich, but it cannot be handled to make money. In the case of the Alaska gravels, there was no available, though essential, water supply. The Kentucky galena cannot be economically separated from the containing heavy spar. Coal, which is sold at comparatively low figures per ton, must be handled at the mines in large quantities to pay, so that a thin seam or a scattered deposit is not suitable for mining.
Under these restrictions of our new definitions, we run across many interesting points. For instance, one may ask the question about the old abandoned hole in the ground which is occasionally found by prospectors, "Is it a mine?" The answer can be simply another query as to whether the hole was abandoned because it contained no value, or because, containing value, it could not be profitably worked. As we think of mines nowadays, we can conceive several reasons why, before the advent of transportation lines and the invention of modern metallurgical processes and many forms of labor-saving machinery now so common in and about mines, many very rich deposits may have been necessarily forsaken by their discoverers. But such a property would, if now worked, probably prove highly profitable. We thus note that there exists some elasticity in the meaning of the word mine. An unprofitable project at one time may develop into a mine at a later period. Many gold mines have become worthless propositions merely through changes in the ore that have rendered further work unremunerative.
[II
WHAT IS MINING?]
Having considered the accepted definition of a mine, let us now extend our reasoning a little and inquire just what is meant by mining. At first thought, one would say that mining is, in a broad sense, the art or practice of excavating, at a profit, the ores of metals, the beds of coal, the gravels of placers and the deposits containing precious stones. Are we justified in letting this definition stand as it is? If we do not make any change, we must exclude all quarries, sand banks, clay pits, and the numerous sorts of works that are producing the non-metallic minerals of commerce. Very well, since we find good usage will warrant us, we will do so.
Hackett Mine and Mill, Joplin, Missouri.
Still, there are other pertinent questions arising. Does the practice of mining cover the treatment of the excavated products? Here we run across a mooted point. The British and the American uses of the word mining seem to be a bit different in this regard. Upon the Rand, South Africa, a territory dominated by Englishmen, every mine is equipped with its own mill, and all notions of mining cover the inseparable idea of local ore treatment. Here, in our country, there are many, many mines which have absolutely no means of treating their own products and the managers give no thought whatever to metallurgical or milling lines. There are, on the other hand, many companies that have erected private plants at their mines for the extraction of metallic contents from the ores. Here it may, or it may not, happen that the operations of mining are considered as distinct from those of treatment. In some instances, as at the Tonopah Mining Company's plants, there is separate superintendence of the milling and the mining; but in the Joplin, Missouri, zinc region one superintendent looks after the running of a mine and its omnipresent mill.
There may be drawn a sharp distinction between what is really mining and what is the subsequent treatment of the ores for the extraction of values. The latter field is denoted Metallurgy when the operations are of such a nature as to actually recover or extract metallic products or metals. If the treatment process has for its object merely the rejection of some of the worthless materials in the original ore, thus causing a concentration of the valuable minerals, but without actually obtaining any metal, then the term Ore Dressing is warranted. At some mines, there is maintained a practice of culling out, often by hand, a certain percentage of the obviously worthless ingredients of the ore before shipping the products to treatment plants. This is neither milling, metallurgy, nor ore dressing, but is more properly called Sorting. It is one of the operations connected with mining. Milling may be either ore dressing or metallurgy.
In the operations of placering, there is a simultaneous excavation of a deposit and an extraction of the valuable contents. In this case, shall we call the process mining or metallurgy? If it is a gold placer, one may see the recovery of the metallic values. Here, the usage of the majority of practical mining men will uphold us in always speaking of the work as mining.
In its original significance and use, metallurgy involved the use of fire for the concentration and recovery of metals. With recent advances in chemistry, there have been numerous discoveries of wet or fireless methods for arriving at equivalent results, so that it is now perfectly proper to allow the word metallurgy to cover such processes as cyanidation, chlorination, electrolysis, and the host of new inventions that are continually appearing.