Mining belts

For some applications it is necessary that static charge should not accumulate on the product. This is important in such diverse applications as mine belting and gramophone records. The use of antistatic agents such as quaternary ammonium compounds has been of some limited value in solving this problem. 

On June 19, 2008, the MSHA published in the Federal Register, a Request for Information (http //www.msha.gov/REGS/FEDREG/RFI/E8-13633.pdf), with comments dueby early September, as to whether tests exist that can be used for assessing conveyor-belt combustion toxicity and smoke density. Comments had to be identified with RIN 1219-AB60 and sent to MSHA. The information collected will potentially result in developing additional requirements for conveyor mine belts. 

Phosphate plasticizers such as tritolyl phosphate and trixylyl phosphate are generally used where good flame resistance is required, such as in insulation and mine belting. These materials, however, are toxic and give products with poor low-temperature resistance, i.e., with a high cold flex temperature (typically, -5°C). 

DIN 22129 1991-4 (1991) Steel Cord Conveyor Belts for Underground Coal Mining, Belt Joints—Dimensions and Requirements. Berlin DIN. 

Kaeprzak, M., Kulinowski, P, W rychowicz, D., 2011. Computerized information system used for management of mining belt conveyors operation. Eksploatacja i Niezawodnosc—Mamtenance and Reliability, 2 81-93. 

Steel tire cord is usually brass plated in order to achieve good rubber-to-metal adhesion. Also, tire bead wire is commonly plated with bronze to achieve rubber-to-metal adhesion. The steel cable used in rubber mining belts may also be brass or bronze plated. 

A surface resistivity of 10 ohm is reported. The use of high stearic acid levels, as in the shoe sole example, is common with NBR blends. Similar plastisols containing antimony oxide for flame resistance are used to coat fabric reinforcements for mining belt covers. 

Aryl Phosphates. Aryl phosphates were introduced into commercial use early in the twentieth century for flammable plastics such as cellulose nitrate and later for cellulose acetate. CeUulosics are a significant area of use but are exceeded now by plastici2ed vinyls (93—95). Principal appHcations are in wire and cable insulation, coimectors, automotive interiors, vinyl moisture barriers, plastic greenhouses (Japan), furniture upholstery, conveyer belts (especially in mining), and vinyl foams. 

Transportation. For short distances from the mine, transportation (qv) is by tmck or conveyor belt. Rail transportation is generally used for greater distances. Slurry pipelines (qv) ate being considered as an alternative. Rail transport over hundreds of kilometers results in loss of surface material in uncovered cats and a tendency to overheat in bottom-dumping tail cats owing to air infiltration around the cracks (31). Proper sealing and covets permit shipping over hundreds of kilometers. 

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. 

Draglines are equipped with a 71-m bucket at the end of a 111-m boom and can be employed to dig both a portion of the overburden, which is free-cast into the mining pit, and the tar sand, which is piled in windrows behind the machine. Bucket-wheel reclaimers, similar to bucket-wheel excavators, load the tar sand from the windrows onto conveyor belts which transfer it to the plant. 

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. 

The usual means of transporting coal are railroad, barge, tmck, conveyer belt from mine to plant, and slurry pipelines (2,4) (see Transportation). In 1988 769 X 10 t of coal was transported to United States destinations of this, 57.5% was shipped by railroad, 16.0% by barge, 12.3% by tmck, and 14.2% by conveyer, slurry pipeline, and other methods (2). Electric utihties consumed 85.83% of the coal transported in the United States in 1988 (2). 

Hydrauhc transport is used in mines and for lifting coals to the surface in Russia, Poland, and France. Pneumatic transport of coal is used over short distances in power plants and steel mills. The longest (14.5 km) single flight conveyer belt in the world near Uniontown, Kentucky, has a capacity of 1360 t/h. 

Improved sensors allow computer monitoring of the system for safety and protection of the equipment from damage. Sensors include lubrication-flow monitors and alarms, bearing-temperature sensors, belt scales, rotation sensors, and proximity sensors to detect ore level under the crusher. The latter prevent jamming of the output with too high an ore level, and protect the conveyor from impact of lumps with too low an ore level. Motion detectors assure that the conveyor is moving. Control applied to crusher systems including conveyors can facilitate use of mobile crushers in quarries and mines, since these can be controlled remotely by computer with reduced labor. 

Industrial equipment is a continuing area of development for plastics. Pipes, pumps, valves and sight glasses, made from such materials as PVC, PTFE and poly-4-methylpent-l-ene, have become well established on account of their corrosion resistance. The nylons are used for such diverse applications as mine conveyor belts and main drive gears for knitting machines and paper-making equipment. These and other materials are widely used where such features as toughness, abrasion resistance, corrosion resistance, non-stick properties, electrical insulation capability and transparency are of importance. 

A slope mine is one in which the coal is of moderate depth and where access is made through an inclined slope (maximum, 16°). This type of mining also may follow the coalbed if the coal seam itself is included and outcrops, or the slope may be driven in rock strata overlying the coal to reach the coal seam. Either a belt conveyor (no more than 30% grade), coal trucks (maximum grade, 18%), or electrical hoist if the slope is steep, can be used to transport coal out of the mine. 

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