Mineral And Energy Resources Test - 2

Certain minerals may occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called ‘placer deposits’ and generally contain minerals, which are not corroded by water. Gold, silver, tin and platinum are most important among such minerals.

A particular mineral that will be formed from a certain combination of elements depends upon the physical and chemical conditions under which the material forms. This, in turn, results in a wide range of colours, hardness, crystal forms, lustre and density that a particular mineral possesses. Geologists use these properties to classify the minerals. The basic chemical materials may be the same, but as the pressure and temperature change, the actual minerals will change too.

In sedimentary rocks a number of minerals occur in beds or layers. They have been formed as a result of deposition, accumulation and concentration in horizontal strata. Sedimentary minerals include gyspum, potash salt and sodium salt.

Minerals are an indispensable part of our lives. Almost everything we use, from a tiny pin to a towering building or a big ship, all are made from minerals. In all the stages of development, human beings have used minerals for their livelihood, decoration, festivities, religious and ceremonial rites.

In sedimentary rocks a number of minerals occur in beds or layers.

They have been formed as a result of deposition, accumulation and concentration in horizontal strata.

Coal and some forms of iron ore have been concentrated as a result of long periods under great heat and pressure.

gypsum, potash salt and sodium salt are another group of sedimentary minerals.

Rocks are combinations of homogenous substances called minerals. Some rocks, for instance limestone, consist of a single mineral only, but majority of the rock consist of several minerals in varying proportions. Over 2000 minerals have been identified, but only a few are abundantly found in most of the rocks.

Life processes cannot occur without minerals. Although our mineral intake represents only about 0.3 per cent of our total intake of nutrients, they are so potent and so important that without them we would not be able to utilise the other 99.7 per cent of foodstuffs.

Geographers study minerals as part of the earth’s crust for a better understanding of landforms. The distribution of mineral resources and associated economic activities are of interest to geographers. A geologist, however, is interested in the formation of minerals, their age and physical and chemical composition. Geographers also study phenomena above the ground and how the features of the planet - ranging from climate to landforms like mountains - affect humanity.

In igneous and metamorphic rocks minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are called lodes. Metallic minerals like tin, copper, zinc and lead etc are obtained from veins and lodes.

Most of the minerals in India are nationalized and their extraction is possible only after obtaining due permission from the government. But in most of the tribal areas of the north-east India, minerals are owned by individuals or communities in Meghalaya. Coal mining in Jowai and Cherapunjee is done by a family member in the form of a long narrow tunnel ,known as Rat hole mining.