Quarry Transport

the moving of quarry loads, one of the main production processes in opencut mining. The basic quarry load is rock (mineral-bearing or barren rock), the starting point is the mining face, and the end point is the unloading area (the dumps for barren rock or below-grade ores and the receiving hoppers of loading stations; the crushing, enriching, sintering, or briquette mills; and the temporary or permanent storage areas for the mineral.)

Special features of quarry transport are the great volume of the shipments (for example, loads ranging from several tens of thousands to tens of millions of tons are moved up to 15-20 km in the quarries per year); the one-directional movement of loads, always from the faces to the receiving areas; the great inclines on the route; and the movability of the rock loading areas and the barren rock receiving points.

Quarry transport is the connecting link in all the production processes involved in working rock in a quarry; it is responsible for about half of the total labor and cost expenditures in mining the minerals.

All types of quarry transport can be divided into two groups: periodically operating transport, including rail and motor movers, skip loaders, and cable cranes; and continuous-action transport, including conveyors, overhead cableways, pipelines (hydraulic and pneumatic), gravity-fed transport (ore chutes and passes), dump transport bridges (trestles), transloaders, and swing chutes. As a consequence of the changing conditions both in the deep and hillside quarries, wide use is made of combinations of different types of transport (for example, motor and rail or motor and conveyor/skip). In this instance, the use of each type of transport for the applications best suited to it provides the highest technical and economic efficiency (for example, motor transport in the face area, skip transport in delivery of the rock from the lower levels, and rail in the last stage of the travel). Aside from the designated means of transport, the rock can be moved in the quarries by stoping-transporting machines (scrapers, loaders, and bulldozers) and stoping machines (high-productivity dragline excavators and mechanical shovels). The most promising means of quarry transport is conveyors, which are used predominantly in working soft rock and which provide continuous mining and full automation of the transporting processes.

Motor-vehicle quarry transport is being improved by increasing the load capacity, reducing the tare weight, improving maneuverability and speed, and improving efficiency (by using an electric drive, gas turbine engines, and storage batteries and fuel cells for power and light alloys and plastics to reduce weight). Rail quarry transport is being improved by increasing the weight of the loads, developing greater climbing ability, and improving braking (the introduction of high DC and AC voltages, diesel electric and turbine engines, and electromagnetic and other types of brakes). Conveyor quarry transport is being adapted for the transporting of hard rock, the conveyor’s angle of incline and the flexibility of the conveyor lines are being increased, and conveyor speed and belt strength are being raised (by using high-test belts and steel, plastic, and other plates; by improving the shock-absorbing devices and transloading points; and using a supporting air cushion).