Assessment of Environmental Impact of Iron Ore Mining and its Mitigation Measures

Abstract

Iron ore is an aggregate of minerals predominantly composed of metallic iron and from which metallic iron can be economically extracted. Iron is the most needed ingredient in manufacturing steel. Steel is by far the most adaptable, significant and widely used of all metals and has found many applications viz. constructions, manufacturing of motor cars, machines, pipelines, military equipment, electrical appliances, etc. For without steel, modern civilization will be absolutely impossible. The amount of energy required to mine and process iron ore is approximately 25% of energy required to extract and process aluminium ore. Thus, Iron ore has been mined for the past three thousand years by ancient and modern mankind. However, mining of iron ore has copious negative impacts on the environment. As the mining method for Iron is usually open cast, it degrades natural landscapes, surface and ground water, flora and fauna, as well as the ambient air quality within the mining area and its environs. Water quality is contaminated due to surface runoff and leachate that are generated from large volume overburden and tailings produced during mining and subsequent processing activities. As most of the mines use overburden as backfilling material for mining out areas, ground water contamination may also result from leaching activities, which may have spartan health impacts on miners and inhabitants of the of the area. The air quality is degraded as well by activities such as drilling, blasting, loading, hauling, and beneficiation of runoff mines. Iron ore tailing (gangue minerals) usually contain large amount of Silica, iron, and traces of Hg, Se, Cu, Pb, Zn, As, Mn etc. that are harmful to humans even at low levels. India is ranked 5th position among countries with highest iron ore reserves on a global scale, while Liberia is a West African nation with significant reserve of iron ore and a major exporter of iron ore among African countries. In the present research work, the air and water quality of two different mining areas of Indian and Liberia are investigated and the quality compared against relevant water quality standards. Moreover, OB tailings and blue-dust samples are collected from both mining areas, prepared as per relevant standard characterized and leached investigate their elemental composition and long term behaviour. Characterization OB, tailings, and was carried out by a combination of several analyses viz. XRD, FTIR and SEM-EDS while the leaching behaviour assessed under two separate leaching conditions viz. double distilled water and TCLP (U.S. EPA) method 1311 (6010B-Lead. ICPMAS analysis was carried out on air borne particulates sampled in the mining area of India. As a means of treatment of turbid raw water gathered from Koira-Joda Mining Area (KJMA), coagulation studies was carried out using two coagulants, Alum and Ferric Chloride concomitantly. The coagulation studies put forward a significant development. The water samples which do not settle easily even after treating them with coagulants like alum or FeCl3 could be settled by using both the coagulants in equal dose. The results from water and air quality tests as well as additional investigation carried out indicated that the air quality and water quality of the mining area is degraded by iron ore mining. Furthermore, results from elemental characterization of OBs, tailings, blue-dust and PM revealed that harmful trace elements like Hg, Pb, Cr, As, Cd, Co. Cu, Fe, Mn, Zn. Ni, Se, Al, Ba, Br, Cations – Na, Mg, K, and Ca present. Therefore, both mining regions are polluted due to iron ore mining but the regions of Liberia is the most polluted.