Deformation Monitoring of Waste-Rock-Backfilled Mining Gob for Ground Control

Abstract

Backfill mining is an effective option to mitigate ground subsidence, especially for mining under surface infrastructure, such as buildings, dams, rivers and railways. To evaluate its performance, continual long-term field monitoring of the deformation of backfilled gob is important to satisfy strict public scrutiny. Based on industrial Ethernet, a real-time monitoring system was established to monitor the deformation of waste-rock-backfilled gob at −700 m depth in the Tangshan coal mine, Hebei Province, China. The designed deformation sensors, based on a resistance transducer mechanism, were placed vertically between the roof and floor. Stress sensors were installed above square steel plates that were anchored to the floor strata. Meanwhile, data cables were protected by steel tubes in case of damage. The developed system continually harvested field data for three months. The results show that industrial Ethernet technology can be reliably used for long-term data transmission in complicated underground mining conditions. The monitoring reveals that the roof subsidence of the backfilled gob area can be categorized into four phases. The bearing load of the backfill developed gradually and simultaneously with the deformation of the roof strata, and started to be almost invariable when the mining face passed 97 m.

The rationale for the development of a method for assessing the roof conditions of mine workings in the conduct of actual mining using the method of geoinformation analysis

“…There are plenty of research methods of roof conditions, the most common are: visual monitoring, georadiolocation, et al [2][3][4][5][6]. The inability to analyze the stressstrain state of roof of mine workings.…”

Experimental Research on Deformation Characteristics of Waste-Rock Material in Underground Backfill Mining

“…The monitoring system was composed of sensors, transmission signal lines, hubs, communication master stations, monitoring sub-stations, a power supply, etc. [38,39] Data were continuously recorded for 45 days, during which the working face advanced 162 m.…”

Prerequisites for the Establishment of the Automated Monitoring System and Accounting of the Displacement of the Roof of Underground Mines for the Improvement of Safety of Mining Work

“…Nowadays, this method is obsolete and has a number of shortcomings [7][8][9]: 1. For specific, clear information, it is necessary to monitor the frames continuously, that is, one directly needs to continuously record the shifts that occurred.…”