Kolhapur district seems to be favorable place in regard to the availability of some of the important minerals. Manganese and Iron ores are found in the southern area of Kolhapur district. Another important mineral found in this district is bauxite. The present research paper deals with the assessment of possible environmental impacts due to the proposed bauxite mining in the area of Shahuwadi of Kolhapur district of Maharashtra. Exploitation of minerals from the earth surfaces through mining activities causes ecological and environmental instability. Impact Assessment Studies are used to quantify impacts of mining activities within the zone of impact. To prevent adverse impacts of mining, environmental management plan is prepared through the findings of Impact Assessment studies. Though mining initially provided employment opportunities for few inhabitants and generated some revenue to Government, it would last only for a small period. However, the damages caused to the regional biodiversity as a result of the changed land use would remain permanent.
Clean and healthy environment is important for the survival and growth of all living beings. Our present environment and ecology is threatened by anthropogenic activities including mining, quarrying and other industrial activities. The growing concern about environmental degradation has prompted the world to think on a new dimension and address the environment-related issues in a more scientific manner. Sustainable development of any region mainly depends on three important aspects: social progress, economic growth and protection of environment. Increased pressure on land for satisfying the greed of human beings accelerated the interventions in the form of quarrying, mining and unscientific conversion of land use etc., which in turn leads to significant land modifications, thereby influencing the biophysical system and adversely affecting the environmental stability and ecological security.
Bauxite is an aluminous rock that contains hydrated aluminium oxide as major constituent and silica, iron oxide, and titania as minor constituents present in varying proportions. Bauxite is a generic name given to various aluminium hydroxides which are genetically related to each other. These aluminium hydroxides are gibbsite and bayrite (Al2O3 3H2O), boehmite and dispore (Al2O3 H2O). Theoretically bauxite contains 73.9% Al2O3 and 26.1% H2O. Bauxite is the principal ore of aluminium which is an important non-ferrous metals used in the modern industries. It is also an important ore for chemical and refractory industries. The country has 3,896 million tonnes of bauxite resources of which are sufficient to meet both national and international demands. Bauxite deposits are formed mainly by weathering of aluminous rock, some have been transported to their current locations, but most are residual accumulations of the constituents of the parent rock, other than alumina which is being leached.
Direct baseline ambient air quality measurements is not available. In accordance with a recommendation made by the Head of the Geophysical Observatory, background concentrations were used based on regulatory requirements for small towns and villages with populations of less than 10,000 persons. Air quality is represented generally in terms of concentration of Sulphur Dioxide, Particulate Matter (PM) and Oxides of Nitrogen. A broad variety of sources contribute PM in ambient air. Some of them are construction activities, vehicular emissions, industrial process emissions, dust storms, etc. It is generally observed that PM levels are higher in dry weather, i.e. during summer and winter seasons. Dust storms generally do not occur. Hence PM concentrations are within permissible limit.
Sulphur Dioxide (SO2) in atmosphere result from burning of sulphur containing fuels viz, coal, lignite, various types of oils etc. Higher concentration of SO2 lead to acid rain affecting the flora whereas, they cause respiratory problems in human beings. Such incident have not occurred in the past. Oxides of Nitrogen are emitted into the atmosphere by the processes involving high temperature combustion. Exhaust gases from motor vehicles are also major sources of NOx. NOx plays a significant role in formation of photochemical oxidants. It is therefore necessary to monitor the ambient air quality in terms of above said parameters to establish the background air quality scenario and assess the impact of distillery plant on the scenario before undertaking any activity.
Noise level is measured in terms of loudness of sound. Sound is a form of energy that propagates through an elastic medium at a speed that is determined by the properties of that medium. Since loudness of sound is important to the effects on people, dependence of loudness or decibel level must be taken into account in environmental noise assessments. Several methods have been developed by researchers using the frequency spectrum of sound at the loudness index of the given sound source. These methods are more complied and time consuming than required for most situations. Therefore simplified techniques have been developed to account for the dependence upon frequency.
Water quality assessment is one of the necessary components of Impact Assessment study. Such assessment helps in evaluating the existing health of water body and suggesting appropriate mitigation measures to minimize the potential impact from development projects.
Theobald, Lakin, and Hawkins (1963) reported the various precipitation reactions associated with Al, Fe and Manganese at the junction of Snake river in Summit County, Colorado with Deer Creek, the latter was highly affected by acid mine drainage from abandoned silver mines. Curtis (1973) quantified selected physicochemical parameters of a small mountain stream in Appalachia, USA to reveal the effects of strip mining activity. Data revealed acidic pH, high TSS, low alkalinity and increased levels of solutes such as sulphate, phosphate and silicate.
Moran and Wentz (1974) summarized quantitative data on water quality parameters for various fresh water resources of selected areas of Colorado, USA, which were impacted mainly by metal mine (silver, gold and copper) drainages. Aston, Thornton, Webb, Milford, & Purves, (1975) quantified the arsenic levels in the surface water of streams and lakes of southwest England, which were affected by long-term copper and tin mining activities.
Johnson, Driscoll, Eaton, Likens, and McDowell (1981) studied the artificial “acid rain” induced changes in the hydrochemistry of a second-order stream in the Hubbard Brook Experimental Forest, New Hamsphire; the major effects appeared to be mobilization of Al from the stream sediment. No significant variations were recorded in metals such as calcium, sodium and Magnesium. Driscoll, Baker, Bisogni, & Schofield (1983) studied and reported the various chemical processes as well as in-stream mechanisms that resulted in speciation of Al in slightly acidified streams of the Adirondock Mountains of New York, USA. Hall, Driscoll, Likens, and Pratt (1985) studied the effects of episodic Al addition to a second-order stream in Habbard Brook Experimental Forest, UK. Addition of Al in the form of aluminium chloride resulted in a significant reduction in pH and dissolved organic carbon and an increase in foam accumulations at the water surface of the stream.
Hall and Likens (1985) have experimentally acidified a poorly buffered mountain stream within Hubbard Brook Experimental Forest, New Hampshire, UK, an effect similar to that of acid mine drainage. Addition of diluted sulphuric acid decreased the pH and increased the mobilization of Al, calcium, magnesium and potassium. Nitrogen was lost via invertebrates and organic matter from the system due to acidification. Johnson (1986) studied the partitioning of the trace metals (Cu, Zn, and Pb) in the Carnon River and Restronguet Creek of England, which were polluted by acid mine drainage and demonstrated the adsorption of Zn and Cu on amorphous Fe oxyhydroxides.
Rampe and Runnels (1989) studied the degree of contamination in a desert stream near Silverton, Colorado, which received metal wastes from an abandoned gold mine. The concentrations of metals in the sediment (Pb, Cu, Zn and nickel) were influenced by the composition and the amount of sorbents that formed, and by the pH which controlled the solubility of the sorbents.
A large-scale study of trace metal distribution in finegrained sediments of Clark Fork River, Montana, USA by Axtmann and Luoma (1991) focused on longitudinal dispersion of metals. Results have shown that trace metal concentrations in sediment declined exponentially with distance downstream from the contamination mines, which are located at Lake Pend Orille mining district. Davis, Olsen, and Walker (1991) studied the distribution of selected metals in the sediments of the Clear Creek, Colorado, which was highly affected by acid mine drainage. Nearly sixty percentage of the dissolved Zn and Cd were removed by adsorption sites on solids suspended in water.
The paper is a part of postgraduate dissertation and is based on field observation and communication with locals, government officials, mine workers and mine owners. For the present impact assessment study, the physical dimensions of the environment such as site location and surroundings, topography, geography, air quality, micrometeorology, noise levels, water quality and all the other dimensions are considered. These environmental parameters are studied to establish the existing environmental scenario of the area.
The Girgaon plateau is about 9 kms south west of Shahuwadi on Kolhpur- Ratnagiri state highway. Nearest Wildlife sanctuary is at Chandoli which is at about 22 km from the lease area. The leased area of the village Girgaon falls in hilly range of western ghat. These hills are covered by Deccan Trap Lave Flows i.e. Basalt rock which is in general covered by flat plateau capped by late rite. These plateaus are dissected by deep gorges at places.
The impacts of mining on various environmental parameters due to mining activity are discussed in the following sections.
The land use in general reflects the activities of human being on land thereby changing the land cover. Identification and periodic surveillance of land use at the working site and in the vicinity of any developmental activity is an important aspect of impact analysis. The neighborhood of the mining area have many villages from Shahuwadi taluka. In the buffer zone, approximately more than 85% of the total land area is suitable for cultivation including the present cultivated area, permanent current fallow land and cultivable wasteland. Excavations are the basic causes of land despoliation. In all surface mining methods, first the overburden has to be excavated and removed in order to reach the ore body creating huge voids.
The mining will be carried out in a scientific manner. The concept of reclamation, rehabilitation and mineral conservation will be implemented in this mine which will result in creation of reclaimed land over the years making it suitable for agricultural purpose and water bodies. The top soil generated is stacked separately and backfilled simultaneously. The mining activities will be completely stopped during rainy days to avoid run off from dumps. Inpit dumping of mine waste will be followed instead of external dumping can reduce land impact. Run-off should be regulated by construction of check dams and garland drains to avoid erosion. Top soils should be kept in a designated area and should be given minimum storage time to prevent nutrient loss. The movement of trucks should be restricted to haul roads. The unpaved roads should be strengthened in order to reduce impact on soil quality.
Different process of handling, transportation, and storage of minerals in the mining activities are prone to generation of higher concentration of fugitive dust that may increase the levels of SPM (Suspended Particulate Matter) to high extent. The effects of air pollutants upon receptors are influenced by concentrations of pollutants and their dispersion in the atmosphere. Air quality modeling is an important tool for prediction, planning and evaluation of air pollution mitigation activities besides identifying the requirements for control of emission to meet the regulatory standards. The efficient management of air quality requires the use of proper modeling techniques to analyze the patterns of pollutant concentrations from all individual sources of air pollutants operating simultaneously.
In the present mining scenario, mining operation such as mining excavation, loading and unloading, movement of dumper and other vehicles on haul road and drilling and blasting are the major source to generate air born fugitive dust. However, the air pollution caused due to ground level sources like area preparation for blasting, drilling operation, movement of vehicles, wind effects etc., does not rise to very high elevation and thus do not disperse beyond the mining lease area.
Mine activities will result gaseous and particulate emissions from various fuel burning in vehicles. These gaseous emissions include sulphur and nitrogen oxides, carbon dioxide, carbon monoxide and particulate matter. Referring the baseline air quality described earlier it is likely that these emissions will not result into a significant addition to the air quality to be called as negative impact.
Dust is generated during blasting, stripping of overburden, drilling, excavations and general materials handling including transport. Windblown dust will be generated in areas that have been cleared of vegetation especially the mine haul roads and the overburden stockpiles. Dust generated does not constitute toxic metals hence it does not poses significant risk on human health. Crushed stone emissions are categorized as fugitive dust emissions. Fugitive emission involves the detrainment of settled dust by machine movement or wind. Fugitive emissions increase with higher wind speed and decrease with moisture content of ore.
A range of mine related activities generate noise and vibration across the mine but it is only blasting that is considered a significant source. According to calculations of current mine activities, the noise level at the Special Protected Zone boundary is less than 50 dB (A) and this has also been confirmed by annual measurements. Although there will be a significant increase in mining activities, these activities will not all be concentrated within the mine area. With the starting of mine operations, deployment of machinery, drilling and blasting for mine development, excavation, transportation of ore and manpower, it is imperative that noise will be generated. Noise has various adverse effects on workers and their activities.
The first and foremost effect of noise on workers exposed to high noise level over a long period of severe impulsive noise of short duration is 'Loss of Hearing'. This effect is either temporary or permanent in nature depending upon the severity and length of noise exposure. Other effects of noise are such as blood pressure, cardiovascular problems and ulcers. Some studies also point to noise related learning difficulties, reduced work efficiency, irritation, fatigue, increased accidents and errors and socially undesirable behavior. Noise generation from blasting: Noise generation from blasting is neither continuous nor for a shorter duration but instantaneous. Only few percentage of Bauxite horizon requires drilling & blasting. It takes less than 5 seconds to occur. Noise of blast is site specific and depends on type, quantity of explosive, dimension of drill holes and type of rock. It is envisaged that the noise impact is marginal as the blasting will be performed during day time and nearly 3 km away from the nearest settlement.
To control the Sound Pressure Levels of the machinery, proper mitigation measures, in order to reduce or avoid the impact of noise sources on the environment should be taken. All noise generating machineries and equipments should be with acoustic enclosures. Adoption of controlled blasting and time delayed blasting which reduces approximately 10 dB of noise at the source. To attenuate high noise levels around the site green belt should be developed.
There is no water bodies present in the mine area or in the close vicinity of it. Voids that will be formed in the lease area due to excavation will be converted to water bodies during the monsoons and can be used as a source of irrigation for agricultural fields in the area near the lease when there is no mining work going on. During mining operations this water is used for the purpose of dust suppression reducing the dependency on other sources of water. The surface water bodies in the nearby settlements are likely to get affected during monsoon season. To reduce this possibility, it is proposed to backfilled material simultaneously at the time generation which will reduce its stacking probability which in turn reduces the possibility of this material being washed out with rain water. Due to this, on a positive note it can be safely concluded that mining activities will not have any significant impact on surface water of the area as adequate safeguard measures will be taken to prevent the impacts.
The process of mining is usually associated with generation of large amount of dust and, the mineral and overburden excavated is converted to loose material. Winds pick up these dust particles along with loose material and deposit them on water bodies. Loose material is also carried by the streams running through the mines which eventually meet the main course or end into a water reservoir causing pollution in both cases. There is significant concern over a large area regarding possible impacts of the mine activities on the streams. The closest point of mining is more than 5 km away from the river and as such there will be no direct physical transformation of the river as a result of pit excavation.
Ground water pollution may take place if dump or stacked material contains chemical content, which will get leached during precipitation and percolate to the ground water. This is not in case with the proposed mine as it does not contain any harmful constituents which could leach down to water table. Moreover, the ultimate mining depth is much above the average water table. Therefore, the ground water level will not be touched during mining process till the end of mine life. Potential impacts of dewatering on regional groundwater include: changes in topography as a result of settling or deformation –formation of depressions; lowering of water table and changes to the ecological character; reduced availability of ground water for other possible land uses (given that there are no communities living in close proximity to the mine); long term effects on the regional groundwater; and reduced water supply to rivers in the area, most notably the through the possible loss of tributaries.
The most significant waste type that is generated by mine operations is overburden which will be temporarily stockpiled before being returned to the pits as part of the reclamation process. However during the first few years there may not be any overburden to be handled. The entire overburden will be dumped in the worked out pits. The dominant hazardous waste type is used oil and oil contaminated materials. These wastes will be sent to authorized recycler. Mitigation must take the form of implementing the components of the waste management strategy. More specifically these include: establishing a dedicated waste transition area that can be used as a central collection for waste and from where the waste, once segregated, can be sent for recycling, recovery or disposal; and preparation of a detailed Waste Management Plan.
The ore loaded in trucks will be transported by road from the site to through the villages Girgaon, Ringewadi and Shahuwadi to State highway Kolhapur to Ratnagiri. Presently Girgaon village is connected by tar road developed under prime minister rural road network. As such, traffic density on village road is very low, hence there is little impact on the traffic of villagers. Once trucks reaches to State Highway, which is 18 meter wide and traffic density is marginal, mining activity will not have any impact on the existing traffic. This is because in one hour two trucks will be added to the traffic of highway due to mining activity.
The mining activity is for bauxite ore. The composition of ore does not have any toxic elements. Secondly, the generation of dust during mining is negligible. Also no toxic gases are emitted due to mining. Hence, negative impact on health worker is negligible. Health and safety aspects of the mine will be given due care. The mine workers who are continuously exposed to dust will be provided with proper protective devices like dust mast, to prevent respiratory disorders. The workers who would be continuously exposed to a high noise levels will be provided with ear muffs/ear plugs. Development of green belt in and around mining lease area is an effective measure to attenuate noise and dust impacts.
The most obvious and direct impact on ecology will be the physical transformation of the landscape as vegetation is cleared ahead of the mine operation. Baseline clearly indicates that lease area is barren waste land and no significant vegetation is required to be cleared. Hence, there is very little negative impact of mining in core zone. However, due transport activity in the buffer zone little negative impact can occur. Vegetation and wildlife present in an area shows certain affinities with its environmental setting and between the species. The animal and plant population in an area form recognizable associations called 'Natural Communities'.
The Natural Communities have structure based on the life forms of the species that make them up. The species composition is referred to the kind of species making up the community. Variety of species and their relative numbers are referred to as species diversity. A community composed of few species is called simple, whereas, that composed of many species is called complex. The vegetation and wildlife describes the environment setting in terms of type of communities, uniqueness, and types of species forming each community, dominant species, rare and endangered species, their habitat vulnerable to various disturbances.
A thorough survey was carried out within the core and buffer zones to get an idea of major plant, animal communities, vegetative patterns, correlation between plant, dominant species and topography, soil, geology, water etc., and present / past human influence on them in order to establish the existing scenario of flora and fauna. There are no endangered species, wildlife corridors, wildlife sanctuary, faunal migratory routes or eco-sensitive area near the whole study area. Generation of dust impacted agricultural activities in nearby areas but it can be minimized by strictly following regular application of water by sprinkling on active areas such as haul roads, dump sites.
Based on the impact assessment study it is observed that there is an increase in the dust pollution, which can be controlled by sprinkling of water and plantation. There is less significant impact on environment and ecology due to the mining activities moreover the mining activities will lead to direct and indirect employment opportunities in the study area. Development of Green belt is not only an effective pollution mitigative technique, but also to control the pollutants released from the premises of the Bauxite Mine.