Design and safety technical measures of the hottes

Water exploration and drainage design and safety technical measures

1. Overview of the working face

12020 working face is located on the +87m horizontal West Wing side of our mine field. The east side of the working face is the goaf of 12020 working face, the South (upper) is the goaf of the upper horizontal working face of the mine, and the West and North (lower) are the original coal seams. The mining coal seam is Wu3 coal. The strike length of 12020 working face (inner section) is 760 meters, the dip length is 150 meters, the coal seam dip angle, the thickness of the coal seam is 0.6-0.9m, the average thickness is 0.69m, and the geological reserves of the working face are 117000 tons. 12020 upper and lower auxiliary roadways are excavated along the coal seam trend

2. Geological conditions

12020 working face, when the upper auxiliary roadway is excavated for 515 meters, and the lower auxiliary roadway is excavated for 650 meters, the new F7 fault is exposed, with a strike of 155 °, a dip of 65 °, an inclination of 48 °, an extension length of about 350m, and a drop of M; The highest altitude elevation of the upper part of the working face is +660 meters, and the lowest altitude elevation is +592 Press the "reset" key to reset 0 meters, the relative height difference is 70 meters, the ground is at the top of Funiu Mountain, the ground is deserted, and there are no residents and buildings

3. Hydrogeology

① atmospheric precipitation, surface water and Neogene phreatic water

according to the spring mechanics test of your company, this area is a low mountain and hilly terrain, with large ground slope, developed gullies, and good drainage conditions of atmospheric precipitation runoff, so there is no perennial surface water body. Neogene strata in the area are sporadically developed, with Deluvial, proluvial and alluvial deposits in gullies and slope toe, with small thickness, complex lithology and poor water yield. In addition, the upper Shihezi Formation has a thick aquiclude, so atmospheric precipitation, surface water and Neogene phreatic water have no impact on the mining of coal seam No. 53. There is only a small amount of dripping water in the exposed interval of the wellbore

② sandstone fissure confined water in the roof of coal seam 53

sandstone fissure aquifer in the roof of coal seam 53 refers to the sandstone fissure aquifer contained within 60m above the coal seam. The lithology is medium grained sandstone, which generally develops 2 ~ 5 layers, with a cumulative thickness of about 0 ~ 30m, generally about 20m. The lithology is complete and dense, the fissures are not developed, and some of them are filled with calcite veins. In the process of production and mining, the fissure confined water of the aquifer will be first filled into the pit, which is one of the main water filling sources of pit water inflow. Because the single layer of the aquifer is thin, the fissures are not very developed, and the supply conditions are poor, the storage capacity of fissure water is limited, the conductivity and water yield are weak, and it is easy to drain in production

③ the sandstone fissure confined water in the floor of coal seam 53 is mainly composed of 1 ~ 2 layers of medium grained lithic sandstone, with a thickness of 2.39 ~ 11.09m and an average of 5.70m. It is argillaceous cementation, and locally contains mud gravel and quartz fine gravel. The sandstone is dense and hard, with undeveloped fissures and weak water yield. It is a direct water filled aquifer in the floor of No. 53 coal seam, which is small in thickness, poorly developed and highly heterogeneous. Because this area is a continental semi-arid climate area, the annual precipitation is mostly concentrated in July to September, its water supply time is short, and the aquifer is covered by Neogene strata, and the supply is insufficient, so its water yield is relatively weak. Generally, it has little impact on the mining of coal seam 53, and there has been no water filling phenomenon in the past mining production process

④ influence of fault structure on water filling of deposit

the main fault structure developed in this area is located in new F7 in the shallow part of the mining area

generally, during the formation of the fault structure, due to the stress traction and drag, a relatively dense plume acceleration gear sample temperature reduction fracture is formed on both sides of the fault zone, which destroys the continuity of the formation and generates varying degrees of hydraulic connection between multiple aquifers. At the same time, the fracture zone provides a channel and space for the migration and enrichment of groundwater. In the mining process, we should strengthen the observation of water inflow at the water inflow point near the new F7 fault

⑤ old gob water in the old kiln

the shallow part of the mining area is the goaf of coal seam 53. It is speculated that there will be old gob water accumulated, which is like an "underground reservoir". The lowest elevation of the shallow goaf is about +100m, which is a potential risk factor threatening the later production of the mine. During production, the upper and lower auxiliary roadways of 12020 should first adhere to the advance detection of DC electric instrument, and when abnormalities are found, drilling verification should be carried out, and a lead distance of at least 30 meters should be reserved. At the same time, flood control and waterlogging drainage should be done well in the corresponding surface subsidence areas of old kilns and empty spaces

⑥ effect of drilling on water filling of the deposit

there is no drilling near the working face, and the tunneling will not be affected by the drilling water

4. Surrounding mining conditions

the south of the working face is the upper horizontal mining area that has been mined, and the west wing is Xinfeng coal mine that is mining No. 21 coal seam

II. Design purpose

1. Explore the geological structure in front and eliminate the threat of water damage to the construction of mining projects

2. Verify the drilling in the low resistivity area of geophysical exploration, or explore the stable fault driven by the first transmission mode of water diversion, so as to eliminate the risk of water inrush

III. design basis

1. Nature of water source: it is estimated that the water source is mainly sandstone fissure water at the top and bottom of the coal seam

2. The mine is equipped with a zby3/7 Zdy-550s grouting pump, two zdy-550s water exploration and drainage drilling rigs, with Φ 75mm and Φ 113mm carbide scraping drill bits (no less than 2 each), Φ 50mm drill pipe, each section of drill pipe is 0.8m long, and the number of drill pipes is 200. All of them use hydraulic powder discharge, and coreless drilling is used for drilling

IV. design parameters of water exploration and drainage drilling

1. Determination of water exploration starting point:

12020, the drilling site of the lower auxiliary roadway is arranged in the direction of 1170m from the opening to the west, and the drilling site support method is 2.5m × The shed is supported by 2.5m I-steel. The shed distance is 500mm, the section is trapezoidal, the net section is 6.0 ㎡, and the tunneling section is 8.0 ㎡. The roadway within 10m of the head-on and roadway "T-shaped opening" and "cross opening" is interlocked and reinforced

2. Determination of lead distance and side slope distance:

12020 when exploring and discharging water from the upper and lower auxiliary roadways, ensure that the distance between the final hole of the drilling hole and the side slope is not less than 20m, and the lead distance is not less than 30m