Research on plugging treatment of flooded mine: Determination of plugging location and optimization of anti-washout underwater concrete ratio

Abstract

A high-quality underground copper sulfide mine in Africa has been flooded for a long time. It is proposed to use underground plugging method and stage drainage to recover underground copper sulfide ore resources. In this paper, 3DMine software is used to establish a three-dimensional mine model, analyze the spatial relationship and connectivity between SS30 safety pillar, roadway engineering and goaf, and then determine the location of water blockage. Then, the anti-washout underwater concrete is proposed for the construction of the cut-off wall. The ratio of anti-washout underwater concrete was designed by a three-factor and three-level orthogonal test, and the optimal ratio of anti-washout underwater concrete was obtained by combining range analysis, variance analysis, SPSS multiple linear regression analysis and MATLAB three-dimensional visualization. The results show that the sealing position is more suitable near the SS30 security pillar (610L, 820L, 1120L, 1440L, 1900L, and 1930L). The optimum proportion of anti-washout underwater concrete is water-binder ratio 0.45, anti-washout content 1.5%, sand ratio 42%. The research results can provide theoretical guidance for the treatment of similar flooded mines, so that the underground flooded mineral resources can be recovered safely and economically.