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1920-1929 most of the tests necessary in perfecting the mechanical principles involved in the con- struction were made at the Somers No. 2 mine of this company. This operation, which is used principally as an experimental one, is located at Belle Vernon, about 42 miles south of Pittsburgh." "It is the dream of every operator to increase production, decrease labor, and at the same time be able to reduce overhead expenses," wrote the editors in their feature on the new Joy machine. Mechanical devices were largely making that possible. "In mines where a friable roof is encoun- tered, machine loading permits of a more rapid advance of room and entries, with a consequent earlier drawing of pillars." In the tests, the Joy machine was used in standard room-and-pillar operation with entries 9 ft wide on 50 ft centers. The coal was first "undercut to a depth of about 7 ft by means of Sullivan shortwall mining machines and shot down in the usual manner with black powder. The Joy loading machine was then employed to supplant" the usual handload- ing methods. "The machine, which weighs about 9 tons, is electrically driven and is 29½ ft long, 5 ft wide and 5 ft high. It is moved under its own power at a maximum speed of 8 miles per hour, the speed of travel being at all time under the control of the operator." As detailed in accompanying illustra- tions, "two conveyors are embraced in the construction. One of these reaches from the gathering mechanism to a storage hopper that constitutes the body of the machine. A second conveyor is utilized to discharge the coal from the hopper in to the mine car, which is located to the rear of the machine. Both conveyors are flexi- bly mounted on the supporting track and may be swung to nearly any angle. This feature of construction permits the machine to traverse short-radius curves such as those at room entrances. The gath- ering mechanism is placed at the forward end of the loading conveyor. Briefly, it consists of a pair of geared fingers that are arranged so as to be positively driven in a fixed orbital path. The initial movement of the fingers is forwards into the coal, after which there is a raking motion across the coal face and then a rearward movement tows the loading conveyor." "After the machine has been brought into the room where it is desired to load the coal, the loading conveyer is lowered so as to bring the gathering mechanism at the front end into contact with the floor The machine is then propelled forward until the gathering mechanism is in close proximity to the loosened coal, after which it is set in motion and machine body moved forward on the track until the fingers in their orbital movement engage the coal and gathering it onto the loading conveyor." "The principals involved in the construc- tion of the machine are departures from any other attempts that have been made along this line…The new loading machine was first placed in service on December 1, 1917, and has been operated continuously ever since. Several of the machines are now in operation, each of which is capable of main- taining an average daily production of 100 tons. This is really a highly conservative fig- ure for an eight-hour day." The initial Joy machine required a three- person crew: operator, a helper and a car pusher. "The operators duty is to supervise the handling of the machine in its various operations and to assist with the cleaning of the coal as it passed up the loading convey- or and into the storage hopper…The duties of the helper are to clean up the coal frag- ments that may be left by the machine in the corners of the room and to assist in sep- arating the draw slate. He may also place such temporary timbers as may be neces- sary. The car pusher's duty is to place the empty car under the lip of the discharging conveyor after the loaded car has been removed by the driver." In the initial tests, almost 40-60 tons of rock was loaded for every 100 tons of coal. But "it is quite proba- ble that if the machine had been operating in a bed free from troublesome draw slate the production would have been nearly if not quite doubled." The new Joy loader was only one of dozens of different machines being devel- oped and pressed into service. To power them, operators were having to choose between direct and alternating current elec- trical systems, then also quite new. In a June 24, 1920, piece, author Charles B. Officer from Chicago, Ill., detailed the history of AC motors being applied to continuous coal cutters. According to Officer, the first of these were deployed during the fall of 1912. "At the at time, a Sullivan continuous-cut- ting chain machine fitted with an induction motor was put into operation by the Star Mining Co. at Rugby, Colo." Shortly after- ward a second, nearly identical machine was employed by the Gordon Fuel Co. at Walsenburg, Colo. "These machines differed from the standard "CE-7" equipment in that an induction motor with suitable starting apparatus replaced the direct-current motor with its starting mechanism. The induction motor and the direct-current machine it replaced were of the same rated horsepow- er." From the beginning, it was "evident that the application of alternating electric cur- rent to coal-cutting equipment was, and would be, successful and economical." At the time of the article's publication, the largest single installation employing AC current underground was at the mines of the Nokomis Coal Co. at Nokomis, Ill. "Here 32 Sullivan "Ironclad" machines are being operated with 220-volt 3-phase 60- cycle current. The Nokomis Coal Co. was the first in the state of Illinois to use contin- uous coal cutters equipped with alternat- ing-current motors. It began the operation of these machines in 1913. Since that date the proportion of coal mined in Illinois with alternating current equipment has increased till now about one-fifth of the coal produced by machines is cut by such equipment." Easier to operate and less expensive to purchase, due to needing less copper, AC Jeffrey pit-car loader—one of the simplest and most effective loading devices thus far developed is the pit-car load- er, which is nothing more than a portable inclined conveyor into which coal is loaded by hand and elevated to the mine car. In wide places portability is most helpful. *Coal Age, January 21, 1926 August 2012 100th Anniversary Special Issue www.coalage.com 49