Mine Haulage.— The transportation prob lem is one of the most important features in the development of the mining industry with which the mining engineer and mine manager have to deal. (It is seldom given a passing thought by the layman). The quantity of mer chantable material handled by the various mines and quarries in the United States during a single year is in excess of 1,000,000,000 tons. The work of the Panama Canal is cited as perhaps the greatest engineering feat in mod ern times, yet the amount of material handled at the canal each year was but slightly in excess of the amount of iron ore and over burden removed annually in two States, namely, Michigan and Minnesota. The task of moving 1,000,000,000 tons of ore, coal and rock would require 20,000,000 50-ton cars. Reducing this to trains of 40 cars, each would represent 500,000 trains. Assuming the average length of a 50-ton car as 40 feet, the length of train required to carry the above amount of ore would be 151,500 miles, or six times the cir cumference of the earth. The mine-haulage problem is usually separated into three divi sions: (1) Underground haulage, that is, from the working face of the mine to the bottom of the shaft or to the surface in the event that the mine is opened by a tunnel or adit. (2) Hoisting, that is, handling the ore or coal from the mine through either vertical or inclined shafts to the surface. (3) Surface haulage, which delivers the ore or coal from the mouth of the shaft to ore bins at smelters or coal tipples at railway yards.
Evolution of Mine Haulage.— In the early years of the mining industry the transportation of ore or coal was crude, and even to-day primitive methods prevail in the more remote districts. In China the ore is transported by coolies, and in some of the mining regions of Mexico Indians carry the ore on their backs for perhaps a number of miles. This class of transportation will apply both to surface and underground workings. In Central America Indians carry ore in a box mounted on two small poles, similar to a hospital stretcher, two men working together. In Peru and Bolivia the llama is the beast of burden and occupies the same position as the burro in Mexico. In early years a large percentage of the coal trans portation underground in Great Britain was handled by women and children. The coal was loaded into buckets which were mounted on sleds and when these were used in thin coal i beds it was necessary for the women or chil dren to creep along the floor on their hands and knees and draw the sled behind them. A laborious task indeed. The next step in under ground transportation was the introduction of two-wheel carts and wheelbarrows, followed by small wooden cars operated on wooden tracks. In 1803 the wooden tracks were first covered with strap iron. The motive power in these cases was largely women and children. and this condition existed in Great Britain until prevented by law in 1842. In 1846 ponies were first used in the English mines. The next im provement was the introduction of iron tracks followed by the use of substantial wooden cars and sheet-iron cars with a capacity of about one ton. The cars were enlarged and horses and mules were introduced into many of the mines, and to-day occupy an important place in underground and surface haulage in both the United States and foreign countries. In many cases the animals are lowered into the mines and remain there until they are either crippled or too old to work. Dogs have been used to some extent for haulage purposes, and as late as 1909 one coal-mining company in Illinois was reported as using 31 dogs for this purpose. Dogs are used in the far North for transporting mine supplies during the winter season, when the snow and ice are suitable for sleighing purposes. Steam locomotives have been used underground since the early 50's, but on account of the smoke given off their use is restricted to small, well-ventilated areas. The compressed-air locomotive was introduced into the mines about 1885 and still occupies a promi nent place in the mining industry. Electric haulage was begun in 1887 and is now common in the large coal and metal mines. The first electric tramway for mine use was installed in Colorado in 1890. In 1890 electrical storage battery locomotives were first considered for use in mines, and to-day they are in successful operation. They are used largely inside the
mines for gathering the coal from the working face and delivering it to the main haulage sys tem. In the operation of these locomotives a track is laid from the main haulage system to the working face, and the storage-battery loco motive operates over these lines without the danger attending installations where trolley wires are in place. The latest motive power i applied to mine haulage is the gasoline loco motive. and tests on this engine indicate that it may be an important factor in underground transportation, providing ventilation is such as to get rid of the waste gases.
Hoisting.— Hoisting through inclined or vertical shafts is the connecting link between underground and surface haulage. In some of the old abandoned mines in Mexico, the pector frequently finds notched poles, named "chicken ladders," which were used by the early Spaniards and the Indians in mining the precious metals. The ore was placed in skin bags containing 50 to 100 pounds each and carried on the backs of the natives as they climbed these poles to the surface. Oftentimes a series of these ladders would cover an tion of 500 to 1,000 feet. Similar methods of ore transportation are still in use in remote districts of China. Vertical ladders were used for many years for carrying ore to the surface, which now find a place only as a ondary escapeway to be used in case of accident. Following this was the intro duction of a crude hand windlass with ropes made from the skins of animals. The hand windlasses are usually known as "Armstrong" hoists, as the power is applied through the arm of the operator. The next improvement was probably in the matter of cables whereby the skins were successively replaced by hemp, cot ton and steel cables. As work pro gressed, the hand windlass was replaced by the horsewhim wherein by means of a long sweep geared to a drum the horse performs the winding as he travels in a circle. Following this was the small steam plant which is now in common use in all prospects and small mines in all the mining districts. These small steam winding plants will handles 500 to 1,000 pounds of ore at a single hoist, and have been gradually enlarged and improved until we have to-day the huge plants with winding drums 20 to 30 feet in diameter and capable of containing 5,000 to 6,000 feet of cable. The largest hoist of this kind is the ne used at the Tamarack shaft, Michigan, where ore is hoisted at a single lift from a depth of 5,260 feet vertically. The Transvaal mines in South Africa are from 2,000 to 5,000 feet deep, and next to our Michigan mines have the best hoisting equipment of any mines in the world. These shafts are equipped with hoisting plants that will handle from 5 to 10 tons of ore at a single trip, at a rate of 3,500 feet per minute. The majority of these larger hoists are operated by steam. The increasing use of electricity has led mining engineers to consider the question of substituting electric motors for the steam hoisting engine. The first electric hoist in America was installed in July 1888 at Aspen, Colo. The motor was seven and one half horse power with a capacity of handling 1,500 pounds at the rate of 100 feet per minute. In 1894, then the largest electric I- iist in the United States was installed in Colorado. The plant consisted of a 150 horse-power motor with an auxiliary 60 horse-power motor. There were two reels, each capable of containing 1,500 feet of 4%-inch X flat cable. The cage weighed 1,375 pounds, and operated at a speed of 600 feet per minute. It had a capacity of carrying an overbalanced load of 10,000 pounds. The Seamans-Miner electric hoisting system utilizes high tension currents that are reduced to about 500 volts. Between the motor and generator is mounted an enormous balance wheel which is kept in continuous motion and absorbs the shock due to the sudden starting of the heavy loads. A hoist of this type is now in use at the Hecla mine, Burke, Idaho. The balance wheel weighs 30,000 pounds. There are two reels, each capable of holding 2,500 feet of a-inch X 4-inch flat steel cable, and hoisting at a speed of 2,400 feet per minute. The capacity of this hoist is 16,000 pounds unbal anced load from a depth of 2,500 feet. The total weight of the equipment is 300,000 pounds.