General Information on Mineral Beneficiation

Mining of coal, non-metallic and metallic mineral deposits produces rawmineral which needs to be processed further by a specified method depending on the mineral and waste product (s) associated with it. The beneficiation methods and its associated processes (gravity separation / floatation / magnetic or electrostatic separation) chosen concentrates the mineral to the desired level. 

An intimate knowledge of the mineralogical composition of the ore is essential if efficient processing is to be carried out. With growing population and increasing demand for minerals for economic growth and decreasing higher grades of resources, there will be tremendous pressure on nations to exploit deposits at lower cut-off grades resulting in unprecedented generation of discarded beneficiation wastes which pose one of the most serious environmental challenges to the industry. The environmental effects are quite often, specific to the mineral/ore being processed.

Problems resulting from beneficiation are generation of solid waste, liquid waste and tailings, resulting from different processing operations. Atmospheric emissions resulting from transportation, crushing / grinding / dry process separation can be minimized by adopting suitable in-process, online control systems.

During mining, metal-bearing deposit, called ore, is extracted from underground or opencast mines. Metal concentrations in ore vary greatly. In order to upgrade the metal concentration, the ores are beneficiated for further use in industries. Mining and beneficiation can have a variety of environmental effects. The most visible effect will be disturbance of land and water regime due to waste disposal. The beneficiation process also includes ore transport, ore handling, crushing etc. Consequently, the environmental impacts of mineral beneficiation on the surroundings are considerable. Many times, the beneficiation plants are located in the mine lease area. The magnitude of environmental impacts in such cases is more significant and they will have add-on effects to the existing environmental conditions. However, mineral beneficiation projects are unavoidable because of commercial use of minerals/ores and their contribution to national economy.

Noting the above, opportunities to minimize significant impacts at the planning and design phases must not be overlooked, as mitigation or restoration during or after construction is prohibitively expensive. It must be accepted that planning of a mineral beneficiation project and its subsequent

operation has some impact on the environment. The purpose of the EIA is to quantify the impact and ensure that changes to the environment fall within acceptable predefined limits. In an ideal situation, the whole EIA process will be undertaken in parallel with the conceptualization, design and operation of the mineral beneficiation plant. While the EIA process can be complex and sometimes expensive, the early identification of adverse environmental impacts can provide the opportunity to take early corrective actions.

To address this, effective government policies as laid town in legislation and regulations, and management policy are important. Self-regulation by the project proponent, including the adoption of good management practices during planning, design and operation stages, will significantly help ensure environmental protection, in which an optimal balance may be struck between socioeconomic, physical, morphological and ecological issues.

Mineral beneficiation is of great economic importance to the mining industry and the country. The continual growth of infrastructure with rapid industrialization, exploitation of minerals is likely to increase. The increasing demand of minerals also promotes mineral beneficiation to upgrade the ore. Mineral beneficiation methods commonly used are for coal, iron ore, asbestos, base metal sulphide ores, potash, tungsten, uranium, gold, titanium and others. Their activities during the construction as well as operational phases may create a wide range of impacts on the environment through activities like crushing, ore handling, tailings management, utilities services etc. The potential adverse effects of mineral beneficiation encompass water pollution of surface streams, groundwater contamination, air pollution, noise pollution, change in drainage pattern etc. The preparation of EIA report and implementation of EMP are essential to effectively manage these adverse effects. The flow diagram for mineral beneficiation plant is given in Fig.1.1