Dynamic characteristics of gangues during vertical feeding in solid backfill mining: a case study of the Wugou coal mine in China

Transporting gangues vertically from surface to underground is a new technology in solid backfill mining, which has been widely used in China. However, the dynamic impact induced by the falling gangues could be a threat to the underground equipment, bringing about serious problems such as abrasion, dynamic impact, air pressure. By analyzing the velocity and interval distance characteristics of falling gangues, this paper explored motion characteristics of gangues in feeding well. The wind resistance test was carried out to measure the wind resistance with different projection capabilities of gangues, based on a wind tunnel test model, which takes the ventilation rate as the control index of falling gangues. Then the motion control equation of gangues and the motion laws are revealed in the falling process. Taking the vertical transportation of gangues in Wugou coal mine, in the northern Anhui Province of China, as an example, the motion laws of falling gangues tested in the site are in accordance with the theoretical analysis.