Meitan kexue jishu (Apr 2023)
Some thoughts and suggestions on the practice of water prevention and control in coal mines
Abstract
According to some hot spots such as exploration before excavation，difficulties like drainage mining under special conditions and contradictory while operating procedures in recent coal mining water prevention projects, confusions brought to production practice and safety supervision are analyzed, some opinions are also put forward. Firstly, the connation of “doubt will be prospected” is discussed in this paper. It is assured that “doubt will be explored” comes after “prediction and forecast”. The “prediction and forecast” are key factors to problems like types of water hazards, water pressure and positions of water, based on what water exploration and release can be designed. From the historical background and realistic conditions, the analysis shows that the exploration before excavation proposed in [2011] No.70 document formulated by Shanxi Province is implemented under specific conditions, with strong pertinence (ancient wells and cellar water). The type of water damage is clear, the space position of water pressure source is roughly known, and the design conditions of drilling hole are available. Therefore, design conditions of water exploration drillings are acquired and “exploration before excavation” is reasonable. However, the scope of “exploration before excavation” cannot be extended infinitely to other fields, otherwise it will be aimless, causing bumps in design, execution and supervision. Secondly, degradation of water on soft rocks is analyzed. Degradations like crumble, rock mud, expansion and floor heave can happen on complicated soft rocks which possess weak cementation, low altitude, high expansion and strong watery, limiting production efficiency. The purpose of pre-dredging weak aquifer under soft rock condition is to improve the production conditions and to increase production efficiency. It is suggested that the regulations should make principles constraints on such drainage holes, so as to facilitate enterprises to formulate construction technical measures in combination with the actual situations. Otherwise, there will be a difference in understanding between government regulators and enterprises. Finally, according to the definition in the procedure, the water-conducting fracture zone does not include the caving zone (above the caving zone); nevertheless, the empirical formula in the procedure and the attached drawings show that the water-conducting fracture zone includes the caving zone, which has inconsistency between the front and the back. For this case, two alternative revision suggestions are advanced. Through the analysis of this paper, some fuzzy concepts are clarified, which is convenient for the production unit to accurately implement the rules and regulations, conducive to the precise supervision of safety supervision department. Besides, dilemma between the supervision department and the enterprise can be avoided.
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