Search Results (2)

Backfill coal mining technology has drawn widespread attention due to its benefits of “controlling surface deformation and subsidence, reducing mining-induced disturbance in the stope, and recycling solid mine wastes”. However, the backfill coal mining technology is still progressing slowly in China. The geological environment of China’s mining areas is complex and highly diversified, and backfill coal mining is expected to fulfill different goals in a wide range of engineering scenarios. These facts explain the poor reproducibility of backfill coal mining projects. This study reviews the existing backfill coal mining systems in China. Based on findings from a survey of engineering cases, we summarize five types of new backfill coal mining methods classified by deployment style; namely, borehole grouting backfill, roadway backfill, borehole–roadway backfill, in situ backfill, and roadway-in-situ backfill. A total of 15 backfill coal mining methods falling into the above five categories are described. An engineering design workflow for backfill coal mining consisting of five steps is proposed; namely, identifying the targets of backfill, analyzing the feasibility of deploying the backfill system, comparing the engineering quantities of different engineering schemes, estimating the economic efficiency of backfill, and backfill performance tracking and monitoring. Real cases of backfill engineering design are analyzed to inform the fast and reasonable design of backfill strategy for specific working faces in certain coal mines. Full article

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operations in underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability in underground workings and then improve ground stability of the whole mine site. However, backfilling step scenarios vary from site to site. This paper presents the investigation of five different backfilling step scenarios and their impacts on the stability of stopes at four different mining levels. A comprehensive comparison of displacements, major principal stress, and Stress Concentration Factor (SCF) was conducted. The results show that different backfilling step scenarios have little influence on the final displacement for displacement in the stopes. Among the five backfilling scenarios, the major principal stress and stress concentration factor (SCF) have almost the same final results. The backfilling scenario SCN-1 is the optimum option among these five backfilling scenarios. It can immediately prevent the increase of the displacement and reduce the sidewall stress concentration, thereby preventing possible failures. Using the same strength of CRF can achieve the same effects among the four mining levels. Applying backfilling CRF of the same strength at different mining depths is acceptable and feasible to improve the stability of the stopes. Full article