Risk Control And Management Of Closed Tailings Pond

Tailings pond is a place for storing metal and non-metal mine production waste,which plays a very important role in the production process of the mine,but it is also a huge source of high potential energy risk.The Yangtze River economic belt is rich in mineral resources,including nonferrous metals,gold,chemical and other minerals.After years of development,there are more than 2300 tailing reservoirs in the Yangtze River Basin,of which nearly 300 are closed for many years.The potential safety and pollution hazards of these tailing ponds are great,which pose a great threat to the water quality and ecological environment of the Yangtze River Basin.Therefore,the research on risk control and risk management of closed tailings reservoir is of great practical significance to the treatment of tailings reservoir in Yangtze River economic belt.In this paper,taking the Fuling phosphogypsum tailings pond of Sinochem as an example,according to the collected data,the risk factors are evaluated qualitatively and quantitatively by using the risk management theory,the risk control engineering is designed,and the risk monitoring facilities are arranged.A complete set of risk management system for closed tailings pond is initially established.The main research results are as follows（1）The risk management system of closed tailings pond is established,including risk assessment,risk control and risk monitoring.Risk assessment is the basic link,risk control is the core link,and risk monitoring is the guarantee link.（2）The contents of risk assessment of closed tailings pond are defined,including dam stability assessment,flood control capacity assessment,seepage water quality assessment and safety assessment,of which the first three are quantitative assessment and the fourth is qualitative assessment.The four evaluation results of the phosphogypsum tailings pond are as follows:the stability of the dam body and the flood discharge capacity of the drainage facilities meet the requirements;The total phosphorus,p H,NH₃-N and F^-in the leachate exceeded the standard;The degree of safety is normal,but there are still some hidden dangers.（3）The risk control project of closed tailings pond is defined,including dam body regulation project,drainage treatment project,reclamation project and seepage water treatment project.The dam body treatment project of the phosphogypsum tailings reservoir includes crack repair,slope repair of accumulation dam,seepage control and improvement of dam surface drainage;The drainage system adopts the mode of combining the drainage ditch in the reservoir and the flood intercepting ditch around the reservoir;In the reclamation project,the reservoir surface and dam surface are renovated in the form of film covering,soil covering and greening;Seepage water treatment mainly uses the seepage treatment station at the downstream of the dam to treat the over standard substances in the seepage water and discharge them up to the standard.（4）The objective of risk monitoring after tailing pond closing is the implementation effect of risk control project.Four monitoring items were designed after the closure of the phosphogypsum tailings pond,including dam displacement,phreatic line,rainfall and water quality around the tailings pond.