In this mineral resources and energy resources post we have briefly explained about mineral resources types, fuel minerals, metallic and non-metallic minerals, use and exploitation, and impacts of mining.
Mineral Resources and Energy Resources
Fuel minerals provide the material used to make most of the things of industrial- based society; roads, cars, computers, fertilizers, etc. Demand for fuel minerals is increasing worldwide as the population increases and the consumption demands of individual people increase. The mining of earth’s natural resources is, therefore accelerating, and it has accompanying environmental consequences.
A mineral is a pure inorganic substance that occurs naturally in the earth’s crust. All of the Earth’s crust, except the rather small proportion of the crust that contains organic material, is made up of fuel minerals.
Some fuel minerals consist of a single element such as gold, silver, diamond (carbon), and sulphur. More than two-thousand fuel minerals have been identified and most of these contain inorganic compounds formed by various combinations of the eight elements (O, Si, Al, Fe, Ca, Na, K, and Mg) that make up 98.5% of the Earth’s crust.
Industry depends on about 80 of the known fuel minerals. A mineral deposit is a concentration of naturally occurring solid, liquid, or gaseous material, in or on the Earth’s crust in such form and amount that its extraction and its conversion into useful materials or items are profitable now or may be so in the future.
Mineral resources are non-renewable and include metals (e.g. iron, copper, and aluminium), and non-metals (e.g. salt, gypsum, clay, sand, phosphates). Minerals are valuable natural resources being finite and non-renewable.
They constitute the vital raw materials for many basic industries and are a major resource for development. Management of mineral resources has, therefore, to be closely integrated with the overall strategy of development; and exploitation of fuel minerals is to be guided by long-term national goals and perspectives.
Minerals in general have been categorized into three classes’ fuel, metallic and non-metallic. Fuel minerals like coal, oil and natural gas have been given prime importance as they account for nearly 87% of the value of mineral production whereas metallic and non-metallic constitutes 6 to 7%.
Coal, oil and natural gas are the basic fossil fuel. We have good reserves for coal but are very poor in more essential fuel oils and natural gas.
Proven coal reserves of the country as on January 1994 (estimated by GSI) is about 68 billion tonnes. We are mining about 250 tonnes annually and this rate is expected to go by 400 – 450 tonnes by 2010 A.D. If we could maintain our mining rate of 400 tonnes per year then the coal reserves might last for about 200 years taking proven reserves as 80 billion tonnes.
The calorific value of coal varies with percentage of carbon present in it. Coal depending upon variation in percentage carbon, can be divided into three categories as follows (bituminous / anthracite type is the most abundant form present in Indian coal).
It is believed that petroleum has been formed over a period of millions of years, through conversion of remains of microorganisms living in sea, into hydrocarbon by heat, pressure and catalytic action.
The petroleum on fractional distillation and further processing provides us numerous products and by-products. Some of the common products obtained on fractional distillation are given in Table, along with the temperature (just below the boiling point) at which they tend to liquefy after crude oil feed at the base is heated to about 400°C.
Mineral Resources and Energy Resources
The proven reserve for natural gas on April 1993 works out to be approx. 700 billion cubic meter (BCM). As regard to production and utilization aspect in earlier years, more than half of gas coming out of the wells remained unutilized.
However, in recent years, we have achieved a utilization rate of 80 – 90%. Keeping in view the future demands and proven gas reserves, it is unlikely that our gas reserves might last for more than 20 years.
Metallic and Non-metallic Minerals
India is poorly endowed with mineral wealth. Except for iron ore and bauxite our share of world reserves of every other mineral is one percent or less.
However, there has been a phenomenal growth in production since independence. As per estimates if the present trend of production continues, we will exhaust our reserves of all the important fuel minerals and fuels, except coal, iron ore, limestone and bauxite, in 25 to 30 years.
Use and Exploitation
The use of fuel minerals varies greatly between countries. The greatest use of fuel minerals occurs in developed countries. Like other natural resources, mineral deposits are unevenly distributed around on the earth.
Some countries are rich in mineral deposits and other countries have no deposits. The use of the mineral depends on its properties. For example aluminium is light but strong and durable so it is used for aircraft, shipping and car industries.
Recovery of mineral resources has been with us for a long time. Early Paleolithic man found flint for arrowheads and clay for pottery before developing codes for warfare. And this was done without geologists for exploration, mining engineers for recovery or chemists for extraction techniques.
Tin and copper mines were necessary for a Bronze Age; gold, silver, and gemstones adorned the wealthy of early civilizations; and iron mining introduced a new age of man. Human wealth basically comes from agriculture, manufacturing, and mineral resources.
Our complex modern society is built around the exploitation and use of mineral resources. Since the future of humanity depends on mineral resources, we must understand that these resources have limits; our known supply of fuel minerals will be used up early in the third millennium of our calendar.
Furthermore, modern agriculture and the ability to feed an overpopulated world is dependent on mineral resources to construct the machines that till the soil, enrich it with mineral fertilizers, and to transport the products.
We are now reaching limits of reserves for many fuel minerals. Human population growth and increased modern industry are depleting our available resources at increasing rates. The pressure of human growth upon the planet’s resources is a very real problem.
The consumption of natural resources proceeded at a phenomenal rate during the past hundred years and population and production increases cannot continue without increasing pollution and depletion of mineral resources.
Impacts of mining
Mining is done to extract fuel minerals from deep deposits in soil. Environmental damages caused by mining activities are as follows,
Subsidence of land: Subsidence of mining areas results in tilting of buildings, cracks in houses, buckling of roads, bending of rail tracks and leaking of gas from cracked pipe lines leading to serious disasters. ·
Groundwater contamination: Mining pollutes the groundwater. Sulphur, usually present as an impurity in many ores is known to get converted into sulphuric acid through microbial action, thereby making the water acidic.
Surface water pollution: The acid mine drainage often contaminates the nearby streams and lakes. The acidic water, radioactive substances like uranium, heavy metals also contaminate the water bodies and kill aquatic animals.
Air pollution: In order to separate and purify the metal from other impurities in the ore, smelting is done which emits enormous quantities of air pollutants. Oxides of sulphur, arsenic, cadmium and lead etc. shoot up in the atmosphere near the smelters and the public suffers from several health problems.
Occupational Health Hazards: Miners working in different type of mines suffer from asbestosis, silicosis, black lung disease.
Adopting eco-friendly mining technology· Utilization of low grade ores by using microbial leaching technique.
In this method, the ores are inoculated with the desired strains of bacteria like Thiobacillusferroxidans, which remove the impurities and leave the pure mineral.
Re-vegetating mined areas with appropriate plants. Gradual restoration of flora· Prevention of toxic drainage discharge.