Coal pillar setting and extracting method for protecting important water body

Abstract

The invention discloses a coal pillar setting and extracting method for protecting an important water body, which comprises the following steps:1) measuring the target water body actually to gain an included angle theta between a water body boundary and a rock stratum, and a head pressure difference P between the target water body to a coal floor, 2) measuring a collapsing angle sigma actually, 3) measuring a coal face actually to gain a maximal water-flowing fractured zone height H1, 4) confirming an ore district critical water bursting coefficient TS, 5) calculating a minimum pillar coal setting width L1 satisfying strength needs, 6) pumping a target water body water-bearing bed and gaining an osmotic coefficient K, 7) measuring a water-bearing bed water level h of any fracture surfaces and a water-bearing bed water level h1 at a part in contact with the target water body, and calculating an infiltration strength W of a water-bearing bed 4, 8) calculating a minimum coal pillar setting width L2 without infiltration flow,9)taking a larger one between the minimum pillar coal width L1 and the minimum coal pillar width L2 as the optimal coal pillar setting width L when the maximal water-flowing fractured zone height H1 is more than or equal to the thickness M of the waterproof layer 3, and taking the minimum pillar coal width L1 as the optimal coal pillar setting width L when the maximal water-flowing fractured zone height H1 is less than the thickness M of the waterproof layer 3,and 10) stopping extraction when the coal floor is extracted to the optimal coal pillar setting width L from the protected target water body. The method has the advantages that implementation is simple and easy; the water resource can be protected efficiently; the mine hydraulic discharge is reduced; and the resource can be extracted safely.

Description

technical field [0001] The invention belongs to the interdisciplinary field of mine hydrogeology and mining engineering, and relates to a mining method based on rock mechanics and groundwater dynamics for protecting coal pillars for important water bodies, and is especially suitable for protecting precious water bodies in arid-semi-arid water-deficient mining areas. Coal pillar left mining method. Background technique [0002] At present, the main raw coal mining areas in my country are generally short of water resources and the ecological environment is fragile. Most of the ecological irrigation, industrial and agricultural water and domestic water in these arid-semi-arid mining areas rely on important shallow water bodies. Therefore, it is of great ecological and social significance to protect these important natural or artificial water bodies while mining coal. [0003] At present, the main method to protect important water bodies is to leave coal pillars. When using the...

AI Technical Summary

Problems solved by technology

One of the main reasons is that the current method of setting coal pillars only considers the compressive strength of coal and rock mass, but does not consider the seepage characteristics of the aquifer. seepage into goaf

To sum up, the existing coal pillar setting methods for important water bodies show the following problems: 1) the purpose of protecting important water bodies cannot be achieved; 2) the amount of underground water inflow increases, and drainage costs increase; 3) there is water inrush hidden danger of sand

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