Environmental Management of Koira Mining Region through Cumulative Impact Assessment Study

Abstract

The iron and manganese ore rich zone of Sundargarh district of Odisha is known as the Koira mining sector, and currently there are 65 working mines. All the mines in Koira mining sector are regulated by a comprehensive set of policy and regulations both at the Central and State levels. Though impact assessment has been done for individual mines, no study has been carried out till date on environmental compliance status taking all the mines together. The environmental impact of a cluster is not only the cumulative effect of all the individual mines and industries but also it should take into account the symbiotic and indirect impact of a region as a whole. Adequacy of the conventional EIA methodology in addressing the overall impact in a cluster has remained questionable. An assessment of the cumulative effects from several industrial projects is an important tool in planning for genuine development (Dutta et al., 2004). Cumulative impact assessment is the process in which the effects of a proposed mine are considered in conjunction with other activities in the general area. A regional concentration of mines will cause cumulative impact beyond those arising from a single mine, e.g. high concentration of particulate matter, impact on surface water quality, severe draw down of water table, deterioration of soil quality etc. Negative groundwater impacts are intensified by several mines in an area and reduced stream flow that can reduce the volume of water available for agriculture. The present work therefore involves the development of a methodology to assess and forecast the environmental impact in a mining area comprising of a cluster of mines, based on which appropriate environmental management practices can be adopted. Air Quality Monitoring (AQM) was carried out at 5 different locations of Koira mining area. The air quality parameters monitored were PM10 and PM2.5, Sulphur Dioxide (SO2) and Oxides of Nitrogen (NOx). The PM2.5, SO2 and NOx concentration in Koira mining area were found to be below the limits prescribed by Central Pollution Control Board. However, the PM10 concentration was found to be above the permissible limit during the summer, as the average concentration was 108μg/m3. Similarly, the air quality index for the Koira mining area for most of the days was found to be satisfactory. However, on a few occasions, it was found to be moderately polluted. This indicates that the mining organizations present in this region have to make additional arrangement for control of particulate matter during summer. The poor air quality index may be attributed to respirable particulate matter and diesel emissions. The major source of the particulate matter is haul roads in mines and transportation roads. Restriction of trucks/dumpers speed and overhauling, and regular road maintenance and cleaning are essential in order to control dust pollution from transportation, together with water spraying on roads. Washing of dumpers/trucks’ wheels/body at an appropriate distance from site entrance, loading and unloading area protected from wind, minimization of drop heights, use of sheet or cover on loaded vehicles and application of water sprays to moisten transported material is also essential. Installation of sprinkling system along with application of binding agents, chemicals on unpaved roads are required. In addition, unpaved roads should be converted to black topped roads, with regular maintenance/ repair of roads to maintain compactness, gradient and drainage. Sweeping of unpaved roads and the imposition of speed limits on trucks and other vehicles was also useful. Regular maintenance of the machines that use diesel as fuel is expected to reduce the NOx emission, thereby improving the quality of air in the area. BOD across all the locations does not exceed the prescribed standard of 30 mg/l. Thus it can be safely assumed that, anthropogenic activities have not affected the steams within the study area. The higher iron content in surface water during monsoon can be attributed towards surface run off from adjoining mines and over burden dumps. The maximum iron content is observed at the downstream locations of Kundra Nala. The iron content of Class-A water as per IS-2296 is 0.3 and most of the stations exceeds this standard. Hence the water is suitable for drinking only after conventional treatment. Higher suspended solids in the surface water during monsoon season are natural consequences of surface runoff during monsoon All the 10 locations, in the study area show uniform variation in TDS levels. Ground water monitoring values during summer when compared to standards show that the pH at all the stations except stations GW2 is acidic. The observed values of iron vary from 0.23-2.65 mg/l while the permissible limit is 0.3 mg/l. The observed values of pH in post monsoon season also suggest the acidic nature of the ground water. The total hardness of ground water at the monitoring stations are within the permissible limits. However, the observed values of hardness are lower during monsoon than that of the summer season because of the ground water recharge. The iron content varies from 0.11 to 0.22 mg/l and is the highest for GW-6 monitoring station. The high iron values can be attributed to the rock formation in the region and groundwater infiltration from iron ore material in the region and overburdens. In the present study, 3.1% of the mining workers had hearing loss. 14% of the workers had refraction error which is similar to general population. But 1% of the workers have defective colour vision which points out the need of initial medical examination and suitable placing of workers. Only 7 workers had hernia. This may be due to statutory requirement of hernia repair for fitness to work. Strict compliance of Initial and periodic medical examinations as laid down in statutory regulations is the ideal way to assess health status of mining workers which can lead the way to prevention of diseases. Further studies with assessment of hazard exposure will be helpful in linking health findings. Regular health examinations, health education and use of personal protective equipment amongst the workers need to be encouraged. Implementation of engineering measures to control exposure will benefit the health and productivity of the miners. Enforcing legal regulations especially regarding environmental monitoring will ensure better working condition. Awareness programs regarding prevention of health hazards in mining industry should be conducted among workers for creating a healthy workforce. Finally, a cumulative environmental impact index (CEII) was developed drawing inference from the framework prescribed by CPCB and was applied to the Koira mining region having a cluster of iron and manganese mines. In order to apply the CEII, certain modifications were made in the original framework to determine the cumulative impact index of a predominantly mineral cluster. The CEII index value determined following the developed method was found out to be 56 which indicate that through there are a large number of mines in operation; still the area is not severely polluted. However, it may be noted that it is approaching the severely polluted criteria. Thus, it is high time that adequate attention may be given to control air, water and soil pollution, so that the index value could be further down which will establish minimal impact of mining in the area.