CHANGING TRENDS IN MINING ACTIVITIES

Mining is one of the oldest activities of man. In man’s early progress mining and the use of minerals were so important that they are reflected in such terms as ‘early stone age’, ’later stone age’, ‘copper age’, ‘bronze age’, and ‘iron age’. The ancient uses of minerals were largely confined to the making of tools, weapons, utensils, the construction of buildings and aqueducts, and road building.

Although the early uses of minerals were relatively widespread, the real development of mining began with the Industrial Revolution, and has continued to be of ever-increasing importance. The development of mining was basic to the Industrial Revolution. Coal and direct water power early replaced the diminishing forests as sources of fuel. Stone and clays provided the materials for factories and other buildings; iron and other materials, for the industrial machinery and transportation industry. Annual mineral output in the world during the 18^th century was very low and only moderate during the 19^th century, but it increased at least eighth-fold in the 20^th century.

The output of minerals as a group is increasing at an accelerated rate. Also, most aspects of mining, ore treatment, and transportation are registering significant changes. An active continued demand for minerals in large part is basically a result of a few things. With the rapid increasing population there are each year millions and millions more mouths to be fed and bodies to be clothed, and many of them depend upon machines, made of minerals, to provide food and clothing. The rising level of living and therefore purchasing power in most technically advanced countries creates ever-increasing markets for a host of things made from minerals. In addition, the underdeveloped nations, striving for a rise in level of living, are using increasing amounts of all types of machines and other products derived from minerals.

It is easily understood that in order to meet such demands changes in mining activities must of necessity take place. As ore bodies are exhausted, new ones in the case of most minerals are found to replace them. Thus the real pattern of mineral production constantly changes. The search, with new equipment and techniques, for new deposits of many minerals is intensifying, because of demand coupled with the exhaustion of rich ore deposits and the working of low-grade ores; an increasing proportion of the world output of minerals comes from low-grade deposits, many of which contain a mineral content of one per cent or less.

The most significant trends in mining and ore treatment are increasing mechanization and output per miner. The old hand methods of mining and ore treatment have been replaced by machines in many parts of the world, but many such mines still operate. Only by the employment of modern machines and technology can many low-grade ores be mined and processed economically; also, the enormous tonnages in large rich deposits can be more efficiently worked only with modern machines.

Since World War II, marked technological improvements have been made in all aspects of mining and ore beneficiation.

In surface mines of iron, coal, copper, bauxite, phosphate rock, and others, the ores after being broken up with new explosives are removed with power shovels or mechanical loaders into dump cars for transportation out of the pit. The newest surface-mining equipment combines excavating, loading, and transportation out of the pit in one continuous process.

In underground metal and nonmetal mines, larger shafts are sunk, larger tunnels are constructed, and ores mined with new drilling machines and more effective explosives are loaded, transported to the base of the shaft. Much deeper petroleum, gas, sulphur, and water wells are being drilled faster, and more economically, with improved tools and methods. Great progress has been made in the mechanization of underground coal mines. About 95 p.c of the underground bituminous coal mined in the United States is cut, drilled, blasted, loaded, and transported with machines, and the percentage is still increasing.

Like improvements are being made in mining, the initial steps in treating ores at or near the mines are being intensively mechanized. Although these steps vary with different minerals, the chief objective of all of them is to increase the mineral content of the material to be shipped. Some of the steps involve physical concentration, or beneficiation. Mechanization is of increasing importance, because a large share of the world output of metals is now coming from deposits with relatively low metal content and because of the rising cost of labour everywhere.

A significant trend in mining and ore preparation is the increasing output per labourer. The output per man per day has increased in most mining activities.

India is endowed with a rich variety of minerals. Large size and geological formations have favoured India in providing wider variety of minerals. There are 4075 mines in India, out of which 522 are fuel (coal and lignite) mines, 714 metallic mineral mines and 2839 non-metallic mineral mines. The mineral sector employ’s over 8 lakh persons and accounts for 11.5 p.c of the country’s industrial output and nearly 3 p.c of the gross domestic product (GDP). It is the mining sector that provides the muscle for the industrial development of a country. Though mining and mineral extraction had been in vogue for several centuries in India, the real development occurred after Independence only. The liberalization policy of the government in 1991 gave impetus to the mining, along with other activities. The new national mineral policy, announced in 1993 has conceded the demands of the private sector.

  Beneficiation = Treatment of ores, etc. to get rid of impurities.