Water-retention coal mining method for cooperatively controlling water level and water quantity of unconfined aquifer

Abstract

The invention relates to the fields of geological engineering and geological environment engineering, is certainly crossed with mining engineering and particularly relates to a water-retention coal mining method for cooperatively controlling the water level and water quantity of an unconfined aquifer. The water-retention coal mining method comprises the following steps: firstly predicting an influence subregion of a fracture field to the bury depth of a phreatic level of a mine lot; selecting a water-retention method for a fade zone of the predicted phreatic level according to vegetation forms; predicting influences caused by full-thickness fully-mechanized coal mining settling of bury depth variation regions of the predicted phreatic level to the bury depth of the phreatic level, the influences caused by full-thickness fully-mechanized coal mining transfluence of coal beds of the bury depth variation regions to the bury depth of the phreatic level, the influences caused by water balance of the unconfined aquifer in a full-thickness fully-mechanized coal mining region of the coal bed to the bury depth of the phreatic level and the total influence amount of the water balance of the unconfined aquifer in the full-thickness fully-mechanized coal mining region of the coal bed to the bury depth of the phreatic level; dividing the bury depth variation regions of the phreatic level into a suitable growth type, a high water-level type and a low water-level type; utilizing different water-retention coal mining methods for different types of bury depth variation regions of the phreatic level; and repeatedly carrying out the steps (5) to (8) every year of coal mining.

Description

[0001] 【Technical field】 [0002] The invention relates to the fields of hydrogeological engineering, geological environment engineering and mining engineering, and in particular relates to a coal mining method for water retention and coordinated control of the water level and volume of a submerged aquifer. [0003] 【Background technique】 [0004] Northwest my country has abundant coal reserves, shallow burial, and superior coal quality, but overall water resources are scarce and the ecological environment is fragile. Coal mining causes water resource loss and ecological environment degradation. Therefore, it is necessary to reasonably exploit coal resources while ensuring that the ecological environment is not affected significantly. influences. At present, there are many methods for water conservation in coal mining. Generally speaking, there are two types of water retention level and water retention capacity. The typical methods of water retention level are: based on mining u...

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Problems solved by technology

[0006] 1) Water-retaining coal mining method with water retention, although irrigation will increase the water content of shallow soil, which can make the growth of herbaceous vegetation not fundamentally affected, but the water demand of trees and other types is relatively large, and immediate irrigation will also cause irreversible degradation of vegetation , this method has limited effect on ecological environment protection

[0007] 2) The water-retaining coal mining method of water retention is a method of pollution first and then treatment. Although the water quality of groundwater can reach the standard after treatment after entering the mine, there are still obvious changes in water quality, such as salinity and pH value. Large-scale use of treated mine water for irrigation and greening will cause changes in soil texture and regional water environment, and the long-term impact on ecology cannot be ignored

But in fact, it is not only the fracture field associated with coal mining that causes the water level change of the phreatic aquifer, but also the subsidence of the rock and soil layer associated with coal mining, the overflow of the aquifer layer, and the water balance change of the regional groundwater. Therefore, the current water retention level Water-retaining coal mining method is inaccurate

[0009] 4) Although the water level coal mining method maintains the water level, sometimes it will cause the decline of the available water resources in the area. For example, the water level coal mining method does not have a large amount of diving into the mine, but the isolation below the aquifer The overall downward subsidence of the water layer causes the depth of phreatic water to decrease, the evaporation of phreatic water to increase, and become an ineffective water resource, which in turn limits human activities in the area and irrigation in the ecological dry season.

[0010] 5) The water conservation coal mining method of water level, in order to maintain the water level, the thickness and method of coal mining in each area will be limited a lot, which makes many coal resources unable to be fully exploited or the mining cost is increased. Although water resources and the environment are protected, But the sacrifice of coal resources is too great

[0011] 6) In the existing water-retaining coal mining method of water-retaining level, only the influence factor of coal mining thickness is used to predict the development height of the water-conducting fracture zone (this is because the method is to offset the influence of overflow by setting the thickness of the protective layer , so as to facilitate the calculation, the equivalent water-conducting fracture development height is only related to the main influencing factor of coal mining thickness), but in fact, there are many factors affecting the development height of the water-conducting fracture zone, and it is impossible to accurately predict the development height of the water-conducting fracture zone. There are fuzzy areas or transitional areas in the existing water conservation coal mining divisions, and the water conservation coal mining method with this type of water conservation level can only be conservative at the expense of water resources or coal resources

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