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Mechanization and Automation in Mining

Because of the high proportion of wages in the cost of production, mechanization is more necessary in mining than in almost any other industry. On the other side, because of the difficult conditions the mineral mined underground must be obtained, the scope for mechanization of the actual production process is limited.

Mechanization is providing human operators with machinery to assist them with the physical requirements of work. It can also refer to the use of machines to replace manual labor or animals. A step beyond mechanization is automation. The use of hand powered tools is not an example of mechanization.

The term is most often used in industry. The addition of powered machine tools, such as the steam powered lathe dramatically reduced the amount of time needed to carry out various tasks, and improves productivity. Today very little construction of any sort is carried out with hand tools. Among the earliest developments in mine mechanization was the introduction of locomotives to replace manual or pony haulage. In present-day mining the operation of loading the mine cars, placing them in the cage at the winding shaft, discharging the cars at the surface, etc., are all performed automatically.

Underground haulage in mine cars and the like has in part been replaced by continuous conveying systems of various kinds such as belt conveyors, steel-apron conveyors, chain conveyors, etc., which can handle up to 600 or 700 tons of material per hour in the horizontal direction and at gradients up to about 12 degrees. Co-ordination of the various mechanical handling appliances is ensured by control centers operating with automatic interlocking optical and acoustic signaling systems in conjunction with measuring and monitoring equipment, overall control being assisted by remote indication of measured quantities, electronic data processing by computers, and a variety of other up-to-date aids.

Underground drilling is now performed by large crawler-mounted power drills equipped with high-alloy-steel or tungsten carbide tipped tools. These tools have swivel mountings and hydraulic feed mechanisms. They can drill blastholes at rates of up to 30m (100ft) per minute. Blasting techniques too have been improved in recent years and are safer and more efficient.

Coal cutters are used to get most of the coal mined by longwall or other systems in Britain. A typical machine for longwall work has a jib provided with a cutting chain fitted with tungsten carbide-tipped cutter picks. The machine, which makes an approximately 5ft. deep horizontal cut, rest on the floor and hauls itself along by winding a wire rope on a drum.

Loaders and cutter-loading machines of American design were introduced into Britain chiefly during and after the Second World War. The majority of loaders employed in present-day mining are of two main types: (1) shovels which pick up and empty in sequence (2) gathering machines with integral conveyors in continuous motion. Shovel-type mobile loaders have been developed since about 1925 and are now widely used in certain types of mining e.g., ironstone mining.

Mechanization has also been applied to the construction of the supports for underground workings. For e.g. a special type of anchor bolt for roof lagging is secured in a drilled hole by means of a screw thread and nut which expands the two halves of a tapered split bushing, so that the bolt is gripped firmly in the hole (Fig.4). A more elaborate and important device is the fully mechanized remote controlled hydraulic chock (Fig.5), which is used to provide temporary support in situations where stability is very important, more particularly at the working face.

Automation plays an increasingly important role in the global economy and in daily experience. Engineers strive to combine automated devices with mathematical and organizational tools to create complex systems for a rapidly expanding range of applications and human activities.

Many roles for humans in industrial processes presently lie beyond the scope of automation. Human-level pattern recognition, language recognition, and language production ability are well beyond the capabilities of modern mechanical and computer systems. Tasks requiring subjective assessment or synthesis of complex sensory data, such as scents and sounds, as well as high-level tasks such as strategic planning, currently require human expertise. In many cases, the use of humans is more cost-effective than mechanical approaches even where automation of industrial tasks is possible.