Groundwater control in open-pit mine with grout curtain using modified lake mud: a case study in East China

Curtain grouting is an effective measure to cut off groundwater flow and reduce mine drainage and the risk of water inrush in open-pit mines. In this paper, an innovative technique is presented in which groundwater flow of the Chengmenshan copper open-pit mine in Jiangxi Province, China, is cut off by using a grout curtain made up of an environmentally friendly material from modified lake mud. An automated grouting control system is used to improve the efficiency of grouting while ensuring grout quality and mine safety. In order to investigate the characteristics of the modified lake mud slurry, a set of orthogonal experiments with three parameters and three levels L 9 (3 3 ) are carried out. The results show that the specific gravity of the basic lake mud slurry is the most significant factor in the effectiveness of grouting. Moreover, the curtain grouting effect of the Chengmenshan copper mine is proved to be excellent through the relationship curve of unit grouting quantity of ZD-I and ZD-II, dispersion coefficient, and water injection tests. It is found that the karstic fractures and tectonic fracture zone are effectively intercepted by a continuous and tight grout curtain located at the east of the mine pit. Our study helps to explore and develop an automated grouting control system and an environmentally friendly material for grout curtains in open-pit mines.