Karst Development Characteristics And Impact Analysis Of Groundwater Environment In Dasha Tailings

With the increase demand of gold, technological innovation and equipment update, the rapid development of gold mining industry, to further expand production capacity, the production brings sewage and offscum due to seepage control measures not in place, to bring greater harm to the environment. In karst region, particularly serious problem is related to groundwater pollution. The study area is located in the Dali in Yunnan province Heqing county west city town Beiya village, Great Sandy Strait tailing pond first-phase project has storage capacity 4.5 million CBM, put into use in October 2010, mainly used for cyanid-bearing tailings storage, until the end of 2013, the tailing pond has been stockpiling 3.5275 million tons. According to the usage of the tailings, can only service to August 2015. In order to ensure cyanid-bearing tailings could be safely disposition, considered comprehensive factors, Beiya mining co., LTD., in June 2014 decided to expand capacity on Great Sandy Strait tailing pond first-phase project, expansion after total dam height of 67.8 m, the total capacity of 17.4528 million CBM.Tailings pone reservoir banks are both outcropped carbonate rocks, covering thin layer, corrosion fracture development, and faults development in the reservoir area, the stratum obviously broken, strong leakage. With the increase of the amount of slag heap, carrying capacity increased, the tailings pond occured differential settlement, therefore the tailings anti-seepage ability does not guaranteed. Monitoring results show that tailings filter workshop the pH value of filter water and arsenic exceed primary standard of sewage discharge, and adjusted water in front of dam is that the pH value of tailing leachate also exceeds primary standard of sewage discharge. Comprehensive analysis that Tailings leachate infiltration pollution area and surrounding groundwater is high possibility and great damage. Therefore, the paper on the basis of summarizing the predecessors’research results, illustrated by the example of the tailings pond, doing systematic research compared.characteristics of Karst region development and the influence of the seepage of groundwater.(1) The paper firstly summarized on research status of leakage in karst region at home and abroad and the study of Karst regions leakage situation arising from the impact of groundwater environment, and corresponding preventive measures and other aspects, for the paper buliding a solid foundation on tailings leakage analysis in karst areas.(2) Through field geological survey and reading collection of data, comprehensive analysis Great Sandy Strait tailings profiles of the geology-engineering environment, finally it is concluded that Great Sandy Strait tailings occured leakage conditions and factors. Thereafter, Summarized Great Sand Strait tailings karst development distribution characteristics and hydrogeological conditions, provided the basis for the analysis of the tailings leakage.(3) The analysis of karst leakage on tailings pond, carrying out the type of karst leakage, leakage approach and direction and estimating the leakage by calculation. Through the macroscopic analysis, it is concluded that the tailings in the process of construction and operation, if not reach the designated position, the leakage will be more serious.(4) According to Technical Guidelines for Environmental Impact Assessment Groundwater Environment (HJ610 ～2011) required the secondary evaluation on groundwater environment, It is concluded that research area of groundwater system high vulnerability and complicated hydrogeological conditions. Great Sandy Strait tailings induced karst collapse during the process of operation, the medium possibility of geological hazards, such as tailings leakage pollution of groundwater, great dangerousness and damage. Induced the high possibility of differential settlement of the ground and less dangerousness and damage. Great Sandy Strait tailings suffered karst collapse during the process of operation, the medium possibility of geological hazards, great dangerousness and damage. Suffered the high possibility of differential settlement of the ground and less dangerousness and damage.According to the result of evalution and in view of the pollution sources, we can come up with the prevention measures and suggestions of the groundwater environment pollution.