QE150 : Evaluation of heavy mextals pollution in water and soil by coal mining in Tazareh mining complex (mine tunnle)
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2009
Authors:
M.rahimi [Author], Behnaz Dahrazma[Supervisor], [Supervisor], Farajollah Ferdoust[Advisor]
Abstarct: Coal mining has caused many water and soil pollutions around the world due to release of heavy mextals, trace elements, nonmextallic elements, and variety of anions and cations. Coal mining activities have been running 30 years in Tazareh Mining Complex located 70 km north west of Shahrood, with 2000 metric tone production daily which made pollution in water and soil in the downstream of the complex, possible. In the present research geological characteristics of the region was studied through field observations, thin sections of the rocks, preparation of maps, and XRD tests. In order to investigate the effects of pollution sources, samples were taken from coal, and dumps (surface and deep) and tunnel drainage. Also, samples were taken from water and soil in upstream, downstream, and in the site of the complex (main tunnel) to evaluate the heavy mextal distribution in groundwater and soil of the region. Physico-chemical parameters such as pH, EC, concentration of organic matter, cations, and anions were measured. Concentration of heavy mextals and other elements including, Cu, Pb, Zn, Fe, As, Cd, Sb, Hg, Sr, Se, Ba, S, Na, K, Ca, and Mg were determined using ICP-MS. Mineralogical studies were performed using rock thin sections, XRD, and field observations. Concentration of elements and other parameters studied in the present research were plotted using Excel while the distribution of these parameters was plotted by Surfer. The results show that highest enrichment factors of the coal are 468, 77, 62, 22.5, 18.2 for Se, Pb, Hg, Ca, and Sr respectively. Average enrichment factors of S and As were 41 and 34 in dumps which are higher than in the coal. Due to abundance of carbonated matter and alkaline, the tunnel drainage was identified as natural alkanity mine drainage (NAMD) with the pH of 7.6. Basic media prevents dissolution and, thus, mobility of heavy elements in the water. Concentration of S, Ca, Mg, Na, K, and Sr, which have a higher solubility in water, were measured in downstream at 9.3, 7.69, 4.44, 1.78, 2.6, and 4.2 times of the upstream in water and 10.5, 2.84, 1.56, 1.43, 1.12, and 4.35 times of the upstream in the soil. Concentrations of sulfate and Ca ions (44.4 and 4.2 ppm) in downstream have been affected the most by mining activities. Field observation and presence of calcite and gypsum minerals indicated a high value of neutralized carbonates and sulfates by the elements such as Ca. XRD tests and thin section samples have shown that calcite, clay minerals, and quartz are exist in the area. Analysis of deep samples from the old coal dumps (25 years) taken from 20-60 cm depth has shown a higher concentration of Cu, Sb, and Ba (with the average of 49.35, 0.46, and 98.1 ppm) in compare with the dump from quarry. The pyrite content of samples was counted for the abundance of S, As, and Fe since they show a high correlation with each other. Variation of concentration of heavy mextal is limited due to high pH (an average of 7.77) while more mobile elements such as S has a higher concentration in 25-year quarry dump (4400 and 7600 ppm in the depths of 0-20 and 20-60 cm respectively) in compare with 2000 ppm in current quarry dump. In general, due to continuous coal mine activities, more severe water and soil pollution in the region is expected.
Keywords:
#Coal mining #Pollution #Soil and Water resources #Heavy elements #Tazareh Mine Complex Link
Keeping place: Central Library of Shahrood University
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