Mining engineering

“ Given that the project has been determined upon, and that the enterprise has entered upon the second stage, that of determination of method of attack, the immediate commercial result limits the mining engineer's every plan and design to a greater degree than it does the other engineering specialists. The question of capital and profit dogs his every footstep, for all mines are ephemeral; the life of any given mine is short. Page 189 Metal mines have indeed the shortest lives of any. ”

“ Although the thoughts of men have been turned to the mineral conditions of these islands for more than two thousand years; and in that period the art of Mining has improved; and the engineering appliances which have been brought to bear upon the ventilation and the draining of mines, are fine examples of mechanical ingenuity,—the science of Mining, however, can scarcely be said to have, as yet, any existence. ”

“ When we have to use drainage tunnels for our mines we carry the water off from the mouth of the tunnel in a flume, placing quicksilver in the riffles, and if it is a copper mine we place scrap iron in the water and we also use the water for power to assist us in mining, so that at the present time we extract and reduce ore at a lower rate than in other parts of the world, for there is no wastefill management and no overproduction, for in all our mining operations we work those that cost the least, and we operate our coal mines in the same way. ”

“ But, of course, more is wanted on a mine than a man who can direct the sinking of shafts, driving of levels, and stoping of the lode. Much loss and disappointment have resulted in the past from unsuitable, ineffective, or badly designed and erected machinery, whether for working the mine or treating the ores. To obviate this defect a first-class mining engineer is required. ”

“ The industry has also profited by the improved methods adopted to facilitate the transfer of the ore in transit and especially by the use of machinery and the mining operations themselves. Furthermore, in the principal mining range—Mesabi—the ore is sometimes found so near the surface that with the removal of a few feet of earth it is mined by the open-pit method, the ore being scooped by huge steam shovels directly from the pit to the car. ”

“ The inequalities of roof and floor, the pitching seams, the folds and faults and fissures, all the [31] accidents and irregularities of formation and of location, make up but a few of the problems which face the mining engineer. But the intellect and ingenuity of men have overcome most of the obstacles which Nature placed in the way of successful mining when she hardened the rocks above her coal beds, crowded the earth’s crust into folds, and lifted the mountain ranges into the air. ”

“ Some mines cannot be economically operated without the treatment of the ores upon, or close to, the mining property. With certain sorts of low-grade ore, or with those kinds of ores that may be concentrated before shipment, provision should be early made for the erection of appropriately designed mills. We say the subject should be considered early, but we do not advocate the premature erection of any mill. ”

“ Speaking broadly, all methods of mining come under the head of either open working or closed working. Open working is employed when the deposits have no overburden of barren rock or earth, or where this overburden is of such small depth that it can be easily and cheaply removed, leaving the coal deposit exposed. The mining of such exposed seams of coal is really a process of excavation or quarrying, and the machines used in making open-pit excavations and in quarrying are applicable to the work. ”

“ Steam shovels, weighing from sixty to seventy-five tons each, do the work. Like a great hand one of these shovels dips down into the soft mass of ore, buries its great dipper until it holds from four to eight tons, and then, groaning and rumbling, slowly lifts its burden aloft, swings it over a car, and the actual work of mining is done. A thousand times a day it will repeat this operation, lifting from three thousand to eight thousand tons of ore. ”

“ The limit, nevertheless, has been reached in many rich mining districts. Pumps of the most approved type, and driven by the largest and most economical steam-engines, have done their best in the struggle against the difficulty; and yet the water has beaten them. Rich as are the lodes which lie beneath the water, the mining engineer is compelled to confess that the metal value which they contain would not leave, after extraction, a sufficient margin to pay for the enormous cost of draining the shafts. ”

“ Thus, in Minnesota, in that wonderful Lake Superior country, that is famous as the world's greatest known producer of iron ore, tremendous tonnages are handled every year by the modern steam shovel, which works in natural light by day and by electric lamps at night. In Utah and Nevada we find similar operations conducted in the excavation of copper ores. In Australia, the famous Mount Morgan mine is using open air methods in the mining of precious metal ore. ”

“ Not so with silver and gold mines. They are most unreliable in both quality and quantity. Costly buildings and machinery are often erected to economize the mining of the ore, only to find no mine to operate by the time the buildings are completed and the machinery is working. ”

“ Access to the buried deposits is gained by vertical shafts. Actual mining is now done to a large extent by continuous miners, machines which bore or rip the potash ore from the face and load it into shuttle cars in one continuous operation. The shuttle cars then transport the ore to conveyor belts which move it to the shafts for hoisting. Working conditions and safety are excellent and have led to high productivity from these mines. ”

“ The law of diminishing return applies therefore to mining, in a still more unqualified sense than to agriculture: but the antagonizing agency, that of improvements in production, also applies in a still greater degree. Mining operations are more susceptible of mechanical improvements than agricultural: the first great application of the steam-engine was to mining; and there are unlimited possibilities of improvement in the chemical processes by which the metals are extracted. ”

“ From the nature of things, metal mines do not, like our cities and settlements, lie in those regions covered deep in rich soils. Our mines must be found in the mountains and deserts where rocks are exposed to search. Thus they lie away from the centers of comfort and culture,—they are the outposts of civilization. The engineer is an officer on outpost duty, and in these places he is the camp leader. By his position as a leader in the community he has a chieftainship that carries a responsibility besides mere mine management. ”

“ Rock and earth on the one hand, and metal and ore on the other, are filled into buckets separately and drawn up to the open air or to the nearest tunnel. If the shaft is not deep, the buckets are drawn up by a machine turned by men; if it is deep, they are drawn by machines turned by horses.
It often happens that a rush of water or sometimes stagnant air hinders the mining; for this reason miners pay the greatest attention to these matters, just as much as to digging, or they should do so. ”

“ When our mining experts discover a mineral belt containing precious metals or copper, iron, lead, nickel, platinum, cobalt, quicksilver, manganese or any other ore used in manufactures and the arts, the first thing we do is to sink a shaft on the most likely ore chimney and at every one hundred feet in depth we run levels to develop it and if we continue to find ore as we go down and the ground requires drainage, we survey for a drainage tunnel that will drain the mine at the greatest depth, even if we have to run a tunnel ten miles. ”

“ As their open trenches and pits could be worked only in the summers, and by methods that made their operations much slower than those of modern miners, no great advance of their work was possible during the working time of each season; and yet remains of their mining works have been discovered wherever mines have been opened in our day; and, as previously stated, they are known to exist in heavy forests, where the modern mining works have not yet been established. ”

“ An engineer provided by Paragon was used to map out or show each of the contractors the particular direction his mine was to take, the locations of adjacent mines, etc. The single engineer was utilized for all of the mines to ensure that they would not run into each other and also so that no minable coal would be rendered unrecoverable by haphazard mining methods. ”

“ An ore must be an aggregate or association of natural [20] minerals, or a single mineral, from which metal may be profitably recovered. Mines are excavations in the earth from which ore, coal or gems are taken. Mining is the art or practice of operating mines.
Throughout the subject, we see the inseparable idea of profit. The work of carrying on operations in a railroad tunnel is not mining; the driving of adits through barren rocks to reach ore bodies is not mining; the sinking of shafts through worthless "wash" or rocks with a view of opening avenues for the removal of ore is not mining. ”

“ The miners do not support the earth by timber or pillars, as they should; the result is that the whole plot of about two hundred acres is gradually sinking, and this will eventually ruin the industry in that part of the deposit. In another part of the same field, a French company has purchased forty acres, and it is mining the whole tract and hoisting through one shaft by steam power. In that shaft they have sunk to a depth of six hundred feet, and are troubled with water and petroleum. These they pump out very much the same way as in coal and other mines, worked in a scientific manner. ”

“ The miners work is as follows; first they sink a shaft so many feet down, and then when they get down deep enough they start sapping forward, putting up timbers as they go. They have to work very quietly as Fritz also does some sapping and if too much noise is made the miners themselves are liable to go up in the air and come down in pieces, and I do not think that anybody would relish that idea. Mining is done now on a very large scale. ”

“ There are regions producing ores that are too refractory for the simple treatments that might be given by company plants located at the mines. There are districts that have many small gold and silver mines with ores that do not yield to simple milling processes and which must therefore be shipped to custom smelteries. Even were the ores amenable to milling of some sort, it is often the case that the mines are not of sufficient magnitude to warrant the maintenance of their own treatment plants. ”

“ 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. ”

“ But, curiously enough, the huge organisations utilising immense masses of lower-grade ores, employing thousands of men and most modern machinery, with smelters at the mining camp, are generally stated to be run at a loss. ”

“ This ore is frequently almost as hard as iron itself, many of the pieces thus dislodged being too large for convenient handling, either by the steam shovel or in the chutes at the wharves, and must be still further broken up. This is sometimes done by the men with picks; but in mining on a large scale, where the deposit is all of a very hard nature, crushing machines are used. ”

“ Roughly speaking, mining methods may be divided into two general classes: (1) surface mining or open work and (2) underground mining.
Open work is done where a small amount only of worthless material must be removed in order to uncover the deposit. This method is employed, for example, in the iron mines in the Mesabi range in Minnesota, where the ore is covered by glacial drift 10 to 100 feet thick. Such covering may often be stripped off with steam shovels. Where the ore is soft and friable, as in the case of some of the iron ore of the Mesabi range, it too can be removed by steam shovels ”

“ Indeed, this system of mining partakes of the nature of quarrying rather than that of mining in the ordinary sense, the ore being scooped from the surface of the ground. One naturally thinks of a mine as being subterranean; but in the great open-pit mines in the Lake Superior region, which are the largest mines in the world, all the mining is done at the surface of the earth. ”

“ Besides the native Kafirs already mentioned, about two thousand white laborers are employed, the greater number being engaged in the offices and workshops and on the depositing floors.
Electric lights are used throughout the mines, and underground work is carried on both day and night by three shifts. Every known scientific device is pressed into service. In all of the deep mines the laborers are taken up and down the shafts in cages.
The method of mining and working the diamond-bearing earth at present employed is far more economical than in former years. ”