Quantitative Evaluation and Case Study of Risk Degree for Underground Goafs with Multiple Indexes considering Uncertain Factors in Mines

The accidents caused by underground goafs are frequent and destructive due to irregular geometric shapes and complex spatial distributions, which caused severe damage to the environment and public health. Based on the theories of uncertainty measurement evaluation (WME) and analytic hierarchy process (AHP), the comprehensive risk evaluation of underground goafs was carried out using multiple indexes. Considering the hydrogeological conditions, mining status, and engineering parameters of underground goafs, the evaluation index system was established to evaluate the risk degrees considering quantified uncertain factors. The single index measurement values were solved by the semiridge measurement function. The weights for evaluation vectors were calculated through the entropy theory and AHP. Finally, the risk level was evaluated according to the credible degree recognition criterion (CDRC) and the maximum membership principle. The risk levels of 37 underground goafs in Dabaoshan mine were evaluated using 4 coupled methods. The order for underground goafs risk degrees was ranked and classified on account of the uncertainty important degree. According to the ranked order, the reasonability of 4 coupled methods was evaluated quantitatively. Results show that the UME-CDRC can be applied in the practical engineering, which provides an efficient guidance to both reduce the accident risk and improve the mining environment.

The Application of Fuzzy Mathematics in Heavy Metal-Contaminated Soils Evaluation and Analysis

The passage set the soils along the river of Dabaoshan mine of Shaoguan city as the research object for heavy metal contamination by means of field investigation and test analysis.Five representative areas were selected,such as liang-qiao village,shui-louxia village,shi-zhuxia village,shang-ba village and xiaba village from upriver to downriver .The concentration of heavy metals including Cd Cr Pb Cu Ni and Zn were evaluated.The methods of establishing fuzzy mathematical models were employed to evaluate the heavy metal element contamination of superficial sediment. Using this method,the extent of pollution increased as follows , liangqiao>shuilouxia>shangba village,the soil quality in these sites were both over the Grade III. And xiaba village>shizhuxia,the soil quality were Grade II.