Abstract:

Currently, at coal open - pit mines in Cam Pha, Quang Ninh, about 20÷25 million tons of coal are exploited annually, discharging about 100÷150 million m3 of tailings. Along with the large tailings volume, instabilities appear at the external dumping sites with diversity and complexity, especially at Dong Cao Son site. After the historically heavy monsoon rain in July and August 2015, many instabilities occurred at the sites. These events were triggered by inappropriate disposal method, large amount of water flowing into the dumping sites, along with the incompatibility of protecting structures. Thus, to increase the stability of the sites, the substitution of waste disposal method, change of parameters of tailings layers, and measures to increase stability as well as the improvement of drainage systems and dykes are essential.