Part 4

Whenever deposits of a broad area, with considerable and uniform depth, are thought to be valuable, it has become a practice to prove their value by "prospect drilling." This is a mechanical method and one form of apparatus employed is of the churn-drill type common throughout oil and coal regions. With these portable machines, holes are put down to bed-rock at intervals across the ground. As they are sunk, the holes are cased with iron pipes, the drillings are carefully saved and washed, and the values are estimated for each foot of descent. From the summation and averages obtained from all the holes, a very fair knowledge of the ground's worth can be obtained.

Intensive placering is now the order of things and the marvelous increase in the use of dredges attests the success which these "gold ships" have attained. It is very interesting to watch the operations of these huge boats loaded with ponderous machines, especially when they are installed in inland regions or up in high mountain gulches. Yet numbers of them are thus in steady use. Wherever suitable beds with a tolerably uniform size of boulders and gravel are found, dams are built to retain the flows of streams until ponds are created of sufficient size to contain and float the barges.

Continual improvements are being made in the construction of these mammoth machines with a view to economy in operations that will result from greater capacities. All costs of placering are reckoned per cubic yard washed. Costs have been rapidly dropping during the past decade until now some companies, with extensive operations, are handling dirt at not to exceed three cents per cubic yard for excavating, washing, wasting the refuse, maintenance, repairs, labor, taxes, interest on investment, and the depreciation of equipment. Such figures will hold good only under very favorable natural conditions of ground and climate such as prevail in California; they have not been attained in the frigid regions of Alaska nor in the torrid South American interior. In view of the wonderful improvements brought forth by mechanical engineers, it is improper to deny that the future will bring still further reductions in placer costs. On the contrary, the signs are good for material reductions.

Dredges are very costly in their installation. They are usually designed to handle so many thousands of cubic yards per day. It has been stated, as a fair but rough rule, that "bucket" dredges will average, in initial cost, one dollar for every cubic yard the boats will handle per month. Thus, if a dredge of this type is built to treat fifty or seventy thousand cubic yards in a month, working steadily, the costs will be respectively $50,000 or $70,000. Other types of dredges, known as the "dipper" and the "suction," will cost less than the bucket type, but have not gained general usage.

"Hydraulicking" is extensively practiced. This term signifies the working of placer deposits by water which is conducted through flumes and pipe-lines and, by means of nozzles called "giants" or "monitors," is directed, in huge jets, against the banks of gravel. These banks or walls are thus torn down and, by the same water, the loosened, disintegrated materials are caused to flow into and through long, wooden, box-like troughs known as "sluices." The floors of these sluices are paved with ribs, cleats or other obstructions termed "riffles" whose function it is to retard and collect the heavy particles which may, later, during the process of cleaning up, be removed as the valuable product. The word "sluicing" is frequently used quite synonymously with hydraulicking.

Costs of this latter sort of placering are considerably higher than those of dredging; but there are many deposits not adapted to dredging operations that may be nicely worked by sluicing, so that there will always be a field for this scheme. Average costs are difficult to obtain since it happens that most of the companies now operating hydraulically are secretive in their accounts. More labor is entailed, more time is required, greater delay is occasioned in cleaning up, and the amount of water used is much greater. Where water is abundant, this last item need not be considered. It is well to remember that even a very large dredge, while requiring a continual and large flow of water through its devices, can still operate with just the water in which it floats, this water being pumped and used repeatedly; whereas, in the case of hydraulic mining, the water may be used but once and, consequently, there must be a large supply and at a good head or pressure.

But, in spite of these disparaging points, we find instances in which, under peculiarly favorable conditions, hydraulicking has been carried on at very low figures. E. B. Wilson says: "The yield of the gravel at North Bloomfield was 7.75 cents per cubic yard; the cost of mining, 4.1 cents per cubic yard. The yield per cubic yard of gravel at La Grange was 10.19 cents, the cost of mining, 6 cents. The costs of mining at these two mines would analyze about as follows: Labor, 60 per cent; supplies, 17 per cent; water, 13 per cent; office, 10 per cent. Ground carrying but 3.99 cents per cubic yard has been worked at a profit at the first mine. With such a small margin to work on, it is evident that skill and executive ability must be provided from the pipemen up." It is claimed that an Idaho mine was worked profitably with less than two cents value in the dirt, but this is to be regarded with some doubt.

There are large deposits in the arid portions of the globe where water for working is not obtainable. To meet such conditions, numerous inventions continue to be placed upon the market. These devices are all planned in such a way as to use very little or no water. If water is required at all, the machines are expected to use it repeatedly. The machines are built to effect the segregation of the precious contents gravitationally, electrostatically, pneumatically, and by amalgamation with mercury. It is too early to say how successful such devices will prove in commercial operations. Because some of them have not "made good" does not mean that genius will not yet cope with the situation; and we look into the future to see large operations efficiently and economically conducted by dry placer machinery. There are now no authentic figures obtainable upon this question of dry placering costs.

VIII

OPEN MINING.

Some mention has been already made of open mining. The greatest development of this sort of mining has come about since the application of the modern steam shovel to the excavation of ore. This practice was an American innovation and it is being adopted throughout the world wherever natural conditions will warrant.

Within the past few years, immense bodies of iron ore have been discovered in northern Minnesota and the adoption of these immense, mechanically operated shovels has worked such economies in the mining of this kind of ore that entirely new cost figures have been established and tonnages are being produced which, a few years ago, would have seemed unbelievable. There are about a dozen mines of this "open pit" type that have each produced over a million tons of ore per year in a season that must cease with the close of navigation on the Great Lakes. One mine has shipped over three million tons a season.

At the Utah Copper Company's mine in Bingham Cañon, Utah, a great deposit of low grade, copper-bearing eruptive rock is being handled upon a steep mountain-side by this same scheme. This ore averages a little less than two per cent. in copper, but so economical is the handling of it in such vast amounts that a neat profit is made above all mining, transportation and milling charges. When the red metal sells at thirteen cents per pound, the gross value of this ore is about $5.20 per ton. This mine has maintained an output of ten thousand tons or more per day over long periods.

A famous gold mine in Queensland, Australia--the Mount Morgan--is also being worked by steam shovel methods. The deposit is here in the form of a small mountain and the operations are gradually razing this landmark to the level of the surrounding plains.

The mining of low-grade _gold_ ores by open-pit methods has taken hold in America, and an example of the practice may be found at the Wasp No. 2 mine in the Black Hills. According to published accounts of the operations of this company, all of the costs of mining and treating the ore amount to only $1.02 per ton. The ore body is a bed of quartzite lying nearly flat, and averaging in the neighborhood of only $2.50 per ton in gold, the only mineral of value. The recovery of this metal is at the rate of between 75 and 80 per cent. efficiency, or about $2 from each ton. The net profit is therefore close to one dollar per ton. This very modern scheme of mining has been made possible through the recent advances made in the cyanidation of ore, and it is going to pave the way for many more such mining plants.

The Nevada Consolidated Copper Company has conducted vast mining operations "in the open" at Ely, Nevada, by the use of 95-ton shovels having a capacity of two and one-half cubic yards per dip. One shovel has handled as high as 2,800 cubic yards (the equivalent of about 5,500 tons) in nine hours; but this must be recognized as an exceptional run, and cannot be taken as an average. The ore has a thickness of about 200 feet and covers many acres. As in the majority of such properties, there is here a large amount of "overburden" to be removed and disposed of before the ore can be excavated. This process of uncovering the ore body by the removal of the overburden is called "stripping." The cost per ton of ore mined is said to average 55 cents.

In an open mine there must be maintained a system of continually changing tracks placed upon grades (sometimes rather steep) and with sharp curves. With multiple switches, numbers of small locomotives are kept busy pulling and pushing up and down the tracks with their strings of loaded cars and replacing the "loads" with "empties." When such operations are upon a mountain-side, a very beautiful panoramic view may be had from the opposite side of the gulch.

Generally, the ore material is disintegrated to some extent. In some cases, it will actually crumble down before the advance of a steam shovel. In other mines, it is necessary to drill large holes which are loaded and blasted.

It is becoming more and more important for the active mining man to post himself upon the methods and economies of this latter-day mining practice. The development of this open or surface mining has introduced entirely new economic ideas. With no costs for timbering of mine passages, for ventilation, or for hoisting, and with a very material decrease in manual labor per ton mined, immense masses of rocks are now really ore, although a few years ago they were nothing but lean, country rock.

In consequence of the success attained by the pioneers in this kind of mining, there has been created a demand for properties possessing large deposits of low grade ore that is workable on this intensive scale. Copper properties have been holding a prominent place recently and stockbrokers carry regular lists of "Porphyries," this nickname having been coined to cover the companies operating in the low grade porphyry ores of the Western United States. Not all of these porphyry companies will use surface mining methods. Some companies in the Globe District of Arizona have started extensive underground schemes for mining large tonnages very cheaply by "caving" methods.

IX

CONSIDERATIONS PRECEDING THE OPENING OF MINES.

The word "exploitation" is used by many mining men and engineers to signify a plan of so opening up ore deposits as to render the contents removable. The same persons use the word "mining" to mean the operations involved in the actual extraction of the ore exploited. It is sometimes difficult to draw any line between the meanings of these two words for, as handled by different men, with varying shades of intention, they are sometimes synonymous. Thus, if exploiting an underground mine, which carries ore right from the surface, means developing the mine in such a way as to provide for a large, steady production, it is difficult to see why the ore taken out in this process cannot be said to be "mined."

By "dead work" is usually meant that work of opening up a mine which will put or keep it in a producing condition but which does not supply any remuneration in the shape of ore (or coal). Again, as used by some men, there is little distinction between this work and exploitation. There may, however, be lines reasonably drawn between these three terms, and therefore the following definitions are proposed:

_Dead work_ is such work as is necessary to develop an ore body, but it does not produce any ore. It may be prosecuted for drainage or ventilation purposes or for creating passage-ways for men and products.

_Exploitation_ is also work performed in opening up or developing a property, but it does not contemplate the value of the extracted materials which may, or may not, be of any commercial importance. Indeed, much ore might be extracted during work which was carried on merely to define extents or boundaries of ore bodies. In this last supposition, the original sense of exploration is brought out and this should serve to fix the definition clearly in mind.

_Mining_ may be restricted to mean the methods and work involved in the profitable production of the mine's ore (or coal). The term would not be used to cover operations of shaft-sinking, tunneling, and the like, unless such work be in the valuable materials. Mining may be said to begin whenever there is produced an output upon which there is some profit. Exploitation may be in valuable ground. If so, we may say that mining is in progress during the exploitation. The driving of levels or drifts in an ore body--or of entries in a bed of coal--produces the valuable products of the mine, and we may, therefore, consider that mining is taking place.

The driving of a crosscut through barren rock to reach an ore body is dead work; but the driving of a drift or level in a vein is either exploitation or mining. Dead work produces _no_ ore. Exploitation may, or may not, produce ore. Mining must produce ore.

Throughout all of the above and the following discussion of this chapter, the reader should bear in mind the point that the word "coal" may be substituted for the word "ore" without altering the substance of the definitions or the conclusions.

Before a mine is opened up, the economist-manager will consider many items. In the first place, care must be exercised in the _examination of the title_ to the property. A mineral property may have passed through the most complicated kind of transfers of fractional interests in the title, just as is true with ordinary real estate. The abstract must be traced back clear to the issuance of patent from the Government, and then on back to the original location. With an undeveloped property (a prospect), this precaution is essential to estop any possible pretensions to ownership, by outside parties, in case the ground subsequently turns out to be exceptionally valuable. It has often been the case that no obstructions from any adverse claimants have been met until owners have, in good faith and at great expense, developed splendid mines. Then suits for possession or partial ownership have been instituted, sometimes with marked success for the plaintiffs. There are persons who make it a special line of business to examine titles to mining property, and it is economy for the average manager to employ such experienced men to attend to these matters.

_Topographical considerations_ will hold a place in the study preceding the opening of a new mine. The nature of the surface of the property and the surrounding country will largely influence in the selection of the proper site for the mine's mouth. Neglect upon this point has been a common cause of failure in mining operations.

A mine opening must be away from all dangers of snow-slides, rock-slides, cloud-bursts and deluges from overflowing streams or breaking dams. It may make a difference in the mine's ventilation as to which direction the prevailing winds blow and therefore upon which side of a hill the mouth be opened.

_Transportation_ facilities must be given due thought. If means are not already at hand, one must inquire into the feasibility of constructing some form of carrier; and here, again, will enter the question of the surface's contour. If a railroad is out of question, possibly an aerial tramway may be constructed. These modern conveyances stop at no obstacles of surface configuration and are dependent only upon the necessity of having the point of delivery lower in altitude than the point of loading at the mine. With some of the modern improvements in these installations, mine products are being transported up-hill as well as down-hill through the application of power. In mining regions, it is generally the case that the mines, themselves, are above the settlements in which are the railroads or treatment plants, so that the mine products will transport readily by the natural force of gravity.

_Climate_ holds an important place in the economics of mining. The working of very rich pieces of ground may prove a losing proposition in some portions of the world where the climatic conditions are such as to render operations possible during only a very small portion of the year. Extremes of heat or cold, malaria or other pestilential obstacles, long rainy seasons with floods, and the hostility of native humans, beasts or insects have accounted for the abandonment of seemingly attractive mining projects.

The question of _labor_ must be given due thought. It is true that the best miners on earth are Americans. We do not deny that many of our miners are of foreign birth, but the fact remains that they perform better and more intelligent service than do their fellow countrymen who have not been adopted into our country. Our men are in demand in the mining development of foreign countries. An American mine manager will always experience dissatisfaction while endeavoring to get, from natives in foreign parts, the same efficiency that he is accustomed to receive from the miners "at home." He may be paying a good deal less per capita for such labor, but he finds he is actually paying more per ton of output.

Even within a single country, there are notable differences in the worth of labor. The natives of some of the Mexican states are far preferable to those of other states. Within the United States, there may be discerned material differences between the efficiencies of the citizens of various sections, when it comes to mining. One cannot procure as competent miners in some of the agricultural states as in the typical mining states. This is but to be expected. For instance, there are deposits of lead ore in the "moonshine" regions of Kentucky which have never been successfully worked, and the real cause of failure, in the writer's belief, lies in the inability of superintendents to obtain real miners either in that region or from the outside. The residents will never become miners; outsiders will not enter for work under existing sociological conditions.

The question of _unionism_ is sometimes held by managers as a deciding one when debating the opening of a mine. While there are those who will broadly denounce such organizations, there may be found other and just as successful mine operators who declare that the effects of union control over their miners are beneficial to their companies' interests. Probably the greatest objection to unionism raised by operators is that they resent the dictation that accompanies the inauguration of union rules in their mines. The owners and managers prefer to run their own business to suit themselves. Some managers are so imbued with this conviction of their own rights that they will refuse to open up mines or, if they are operating, they will close down their mines before they will submit to the demands made upon them by the union officials.

On the other hand, there are mine managers who prefer the presence of some central, labor-controlling body; for they believe that the men who belong to such a large federation or organization will, and do, have less complaint to make and therefore work more freely than is the case with the independent laborers. The argument is that these union men are satisfied because they feel that their interests are being looked after with a sort of attention that they, individually, could not give.

This is not a place to discuss the crimes that have been laid at the doors of both the labor organizations and the mine owners' associations. It is safe to assume that wrong has probably been done by both sides. But it is furthermore right to believe that most of the crimes were not authorized, nor recognized, by the officers or the majority of members of either side. Individual members must not be taken as averages of the membership in any kind of civil, social or political organization.

It seems entirely wrong that _politics_ should enter into the considerations of a mine manager whose operations are apparently so apart from affairs of state; but the fact remains that there are places where mining operations cannot be carried on without the good will of certain officials of the state or national governments. It is not advisable to enter into any compromising terms to gain privileges for carrying on any legitimate business for there are other, better ways, generally, of attaining the justice that is deserved.

One must not omit to investigate the _sources of supply_ for all the needs of a mine and its camp. There are many kinds of materials needed to keep a mine going. Fuel, machinery, timber, water, food for men and beasts, lumber, and all household furnishings and necessities must come from some markets or natural sources. It behooves the cautious manager to see that all these things may be had in ample amount and at figures which will not prove annihilating to his business.

In Utah, there are mines which have all their timbers framed in and shipped from the forests of Oregon, the sawing and framing being done before shipment to save on freight. The fir of Oregon is shipped to distant Australia for mining purposes. The arid camps of Nevada get their supplies of timber from the sister state, California. The Michigan mines are fortunate in being in a lumber region. Colorado's metal mines are more favored in the matter of timbers than are the coal mines of the same state. Most of the coal mines are upon the barren plains, while the metal mines are chiefly in the wooded mountains.

Water may be too scarce for the needs of a mine or its community. There may not be sufficient to supply boilers or a mill, or for the domestic purposes of the workers. On the other hand, water may be so abundant in the mine workings as to prove a deterrent factor in profitable operation. With shaft mines, having deep workings and low grades of ore, if water must be delivered mechanically, the costs for such drainage are frequently prohibitive of mining. Some mines, in arid regions, have been fortunate in striking such flows of underground water that it has been possible to operate mills right at the mines. In this way, the cost of water hoisting has been more than compensated in the milling benefits which, in turn, have decreased freights and treatment charges.