Evaluation of the Effect of Mine Extraction and Sodium Sulfate Processing by Mass Balance at Mighan Desert

During the past years, significant climate changes and the uneven and unpredictable development of Arak urbanism toward the Mighan desert have challenged Iran s Amlah Mining Company activities in the field of extraction, mineral processing and transportation related to the environment. In this paper, the hydrogeological chemistry balance of solutes related to extraction, transportation and processing was evaluated. Geological data, periodic climate change, lithology and groundwater hydraulic coefficients were studied more than 100 wells within and around the mining area. Based on the analysis of the results, the present conditions of Mighan desert lake is considered as a temporary suspended lake (summer). By comparing the results of ore extracted and water balance analysis of wells around Lake Mighan, the wells are not currently contaminated by ore extraction activities. The share of water in the extracted ponds was less than 2% of total water area in the last month of 2016. According to the meteorological and regional database obtained from 2001 to 1986, the rainfall amounted to less than 500 mm, while evaporation was higher than precipitation and was recorded at about 2500 mm. Planning for proper regeneration during extraction can expect to increase the surface water cover to at least about four square kilometers after the plant s tailings are fully transferred to the extraction basins. Current sodium sulfate mining salt extraction method in Mighan desert is an open-field extraction in semi-aquatic environment without performing leaching pits and salt extraction from saline, but incompletely running. Due to the presence of water during the extraction process, the proper implementation of this method of extraction is currently hampered by the fact that if the tailings of the plant are pumped to the ponds and transferred to the brine in order to make roughness of mining areas and renovation in the vicinity of the plant, the mineral extraction conditions are met. It is relatively simplified and provides ample opportunity for timely reconstruction of the extraction sites. According to the calculations of the solute mass balance, the minimum level of water altitude so as not to be retarded by the transfer of the entire tailings tail was reached to 1656 m. In exchange for the transfer of four million tons of plant tailings, at least the right of entry to Lake Mighan from the Arak treatment plant is estimated at 316 liters per second in July and August each year to retain 60% soil moisture in the wet lake.