Study On The Characteristics Of Water Storage Layer Of Underground Reservoir In Open-Pit Mine

In order to solve the problem of the imbalance between the seasonal supply and demand of water resources in the large-scale coal power bases in the eastern grasslands of my country,it is proposed to establish an open-pit coal mine underground reservoir to store,purify and reuse the pit water.In this way,the utilization rate of water resources can be significantly improved.Ecological environment,faster and better construction of environmentally friendly ecological civilization mining areas.Based on the water storage characteristics of the water storage layer,based on the similarity theory,this paper applies the dimensional analysis method to derive the similarity criterion of the similarity model of the water storage layer,determines the similar conditions between the model and the prototype,and designs the test device for this similar simulation test.Undisturbed sandstone(gradation 1),sandstone with a particle size of 2 mm or more(gradation 2),and sandstone with a particle size of 10 mm or more(gradation 3)are used to study the water storage performance.At the same time,the influence of each level on the water quality of the mine is analyzed.Based on the resource development conditions and material conditions of the Baorixile open-pit mine,an integrated method of mining,drainage and rehabilitation for the construction of underground reservoirs is proposed.The main conclusions of the thesis are as follows:(1)The gravel-bearing sandstone in the overlying rock layer of the coal seam is selected as the water storage material.The sandstone is a coarse-grained soil with well-developed pore structure.Its uneven coefficient C_u is 35,and the curvature coefficient C_c is 1.17.It belongs to a good gradation and can be used as a water storage layer material for underground reservoirs.(2)During the test,gradation 2 and gradation 3 have the characteristics of small displacement change,high water storage coefficient,fast flow rate and obvious moisture change.Compared with gradation 1,they are more suitable for water storage materials.(3)By analyzing 8 water quality evaluation indicators such as turbidity,hardness,chemical oxygen demand,ammonia nitrogen,nitrite,electrical conductivity,p H and heavy metal content,after confirming that the mine water has been cleaned,selecting gradation 2 as the water storage material can achieve good water storage effect.(4)According to the seasonal water demand and the geological conditions of the mining area,it is determined to build a group of underground reservoirs with a storage capacity of 1×10~6m~3in the west area of the Baorixile Open-pit Coal Mine.The unit storage capacity construction cost is about 18 yuan/m~3,The construction cost of the unit storage capacity is about 18 yuan/m~3,and the estimated unit storage capacity can save water about 6.5 yuan/m~3 based on the annual deployment.The static investment recovery period of the project is 3 years.The paper has 38 pictures,10 tables,and 117 references.