Shuttle cars

Sylvinite ore is relatively soft and easily broken. Thus, continuous miners of the boring- or rotating dmm-type can be used. These machines are modified continuous coal miners. This method is used in some of the mines in New Mexico, in all Canadian mines except the solution mines, and in many European mines. Ore is removed from the face by a number of methods, eg, with extensible belt conveyor ore-loading machines and shuttle cars to the main haulage line. To obtain maximum benefits from the continuous miners, the ore transport system must be as nearly continuous as possible. 

The mechanical equipment used in room-and-pikar underground mining usuaky involves a series of specific operations with continuous mining equipment. Continuous miners use rotating heads equipped with bits to pick or cut through the coal without blasting and load it into a shuttle car for conveying to a belt system. 

After breakage the coal is loaded directly into track-mounted mine cars or into rubber -tired electric trucks known as shuttle cars. Sometimes it is loaded directly into chain-or belt-conveyers. After the coal is loaded into shuttle cars or conveyers in the production area, it is transferred to the main haulage system, which consists either of rails or conveyers... 

Belt feeder (feeder breaker) crawler-mounted surge bin often equipped with a crusher or breaker and used in room-and-pillar sections positioned at the end of the section conveyor belt. It allows quick discharge of a shuttle car. It sizes the coal, and a built-in conveyor feeds it at an appropriate rate onto the conveyor belt. 

Shuttle car-hearth furnaces and kilns are hybrids between batch and continuous furnaces and kilns, combining the compact lower cost of a batch operation with the productivity and fuel economy of a continuous furnace or kiln. A shuttle furnace has doors at both ends and with two rolling hearths, permitting quick unloading and reloading of the furnace with minimum cooling during the switch-around. (See fig. 4.8.) The capital cost is only about 65% of two furnaces, but the production rate is almost doubled. The fuel economy per year and per ton heated is better because the doors are closed and the burners are in use more often. 

August, 99 men were killed in an explosion in a mine near Kemmerer, Wyoming 1930 Molded, protective helmets for miners are introduced 1937 The shuttle car is invented... 

In conventional mining, miners use power saws to slice a deep cut 10-12 ft (3-4 m) wide, into the bottom of a coal wall. Next, holes are drilled into the coal above this cut and fill the holes with explosives. The explosions dislodge chunks of coal from the wall. Conveyors or rubber-tired electric vehicles known as shuttle cars carry the coal chunks out of the mine. 

Blast mining (sometime referred to as conventional mining) is an older practice in which explosives (such as dynamite) are used to fracture the coal seam, after which the coal is gathered and loaded on to shuttle cars or conveyors for removal to a central loading area. This process consists of a series of operations that begins with cutting the coal bed so it will break easily when blasted with explosives. 

Continuous miner A mechanical mining machine consisting of a cutting head, a coal-gathering device, a chain conveyor with flexible loading boom, and a crawler-equipped chassis. Its function is to excavate the mineral and to load it onto shuttle cars or continuous-haulage... 

Loader A crawler-mounted unit equipped with a coal-gathering device mounted to an inclined feed plate at the front side. A chain conveyor with an articulated loading boom discharges the coal at the opposite end into shuttle cars or any other conveying systems. It is used primarily on conventionally mined room-and-pillar sections and resembles a continnous miner without the cutting head. 

Shuttle car A rubber-tired vehicle used to haul coal from the continuous miner or loader to a belt feeder or conveyor belt. It is usually electrically powered, with the power supplied through a trailing cable. Some new models are equipped with diesel engines. 

Underground mine Also known as a deep mine, usually located several hundred feet below the earth s surface an underground mine s coal is removed mechanically and transferred by shuttle car or conveyor to the surface. 

Single Conveyor Shuttle Car Loading with Rock Box... 

The option depicted in Figure 7 is indicative of a single conveyor with a shuttle car and rock box. The material trajectory into the skip is governed by the chute and shuttle car arrangement, along with the upper rock box design. 

This option has a multitude of wear surfaces associated with its material transfer prior to entering the skip. These include the rock box lip, shuttle car, adaptor chute, the chute far wall and the floor of the transfer chute. Several changes in direction of the flow of material in this design introduce the additional wear points. This design is also the least time-effective of all options due to the multiple changes in direction of the ore flow within the pocket and the requirement for a gate. 

The rock box that was presented in the previous option is replaced with a deflector plate in this design. The addition of this plate helps to avoid the subsequent excessive time delay from the dribble effect of material. An additional wear surface is introduced, but the required skip docking time is reduced. The skip docking duration is longer than with the other designs, but shorter than for the shuttle car with rock box option. A knife gate is not required in this design. 

Figure 8. Single conveyor skip arrangement with a shuttle car and deflector plate...

The data in Table 3 indicates that the direct loading designs have the highest wear on the skip back wall liners. Practically, this makes sense as the direct loading options have the highest velocity due to the height of free fall uninhibited by shuttle car or chute impact surfaces. 

Shuttle car loading options also exhibit significant skip liner wear as these designs have more chute work and elevation for the material to accelerate than the remaining options. 

The dual conveyor option becomes the most expensive primarily due to the cost of the conveyors and the additional excavation requirements to house the conveyors. Comparable results are attained for the remaining options as the extra expense of the slewing conveyor feature in the slewing conveyor options offset the cost of the additional chutes and shuttle car in the single conveyor shuttle car loading design. 

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