The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

279 / 2018-04-25 22:14:55

A Case Study on the Risk Assessment of the Overhead Tailings Dam

overhead tailings dam; tailings dam break; natural gas pipeline explosion; numerical simulation; explosion seismic effect; risk assessment

Mine Dynamics Disaster > tailings pond

A tailings dam with residents or important facilities in the range of one kilometer downstream is called the Overhead Tailings Dam, which would cause a serious accident after the dam break. It is extremely necessary to carry out a risk assessment on this kind of tailings dam, including analyzing the influence range after dam break, putting forward prevention and control measures, especially evaluating the interaction between the tailings dam and its downstream constructions. For a long distance natural gas pipeline in the downstream of a tailings dam, a further assessment of the damage caused by destruction of the important facility is needed. Taking the overhead tailings dam in Longyan, Fujian as an example, the two-dimensional hydrodynamic module of MIKE21 developed by Danish Hydraulic Research Institute was used for the numerical simulations of tailings dam failure. By setting the initial conditions, boundary conditions and other parameters of the numerical simulations, two-dimensional dam break evolution model was generated, and the flow process, the maximum velocity and other data in the dam break area were obtained. Based on these simulation analyses, the scour depth of the buried surface of the pipeline and the overall impact force on the pipeline were calculated, and whether the impact force of the tailings debris flow could cause the fracture of the pipeline was assessed. By using the CASSTQRA quantitative risk assessment software for major risk sources 2.1 version, the range of casualties caused by an explosion in the pipeline after completely broken for some reason was simulated. And influences of shock waves and explosion vibration caused by an explosion of the pipeline after complete rupture on the tailings dam were analyzed, which provided a technical support for the treatment of this overhead tailings dam, and provided a method for the risk assessment of the Overhead Tailings Dam as well.