Mine exploitation

Tongxiang is conveyor equipment manufacturers.Our products are widely used in mining exploitation.In Mining exploitation:
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First, you need to excavate the passage from the ground to the ground. A coal mine has at least two passages, one called the main well for transporting coal and the other for the transportation of personnel, equipment, equipment, and transportation of meteorite. In addition, a specially ventilated air shaft is also required. The main well and the auxiliary well are generally built in the same industrial square. If the central ventilation is adopted, the wind well is close to the main and auxiliary wells. If the diagonal ventilation is adopted, the wind well is built at the boundary of the well field.
After the wellbore is excavated to a predetermined depth, a series of tunnels and chambers are to be excavated above and below this elevation, which mainly includes the bottomhole parking lot, transportation laneway, Shimen, uphill and downhill, return air laneway, associated roadway, and underground coal. Warehouse, water warehouse, pump room, substation, pressure fan room, warehouse, etc. This level is called the production level. These roadways and chambers have been providing services throughout the entire production period of the mine.
The underground coal seam is divided into several areas for mining. This area is the mining area. According to production requirements, coal seam thickness, and coal mining methods, a mine can be produced in one mining area or in multiple mining areas. A new mine has developed a whole mine transport and ventilation network for its development project, and prepares a mining area that is suitable for the design output and can transfer it to production, which is called production. In the production and mining area, for the purpose of coal mining, a lot of roadways need to be excavated. These roadways, along with the abandoned coal, are called production excavation and are not part of the development of minefields.
2. Way of development

Including shaft development, inclined wells, flat development and comprehensive development.The development of shafts from the ground to the bottom of the depot is the shortest distance, most of the coal mines use it. The average depth of vertical shafts was 595.8 m in 1990. There are also many vertical shafts in the eastern region that are more than 1000 meters deep. Wellbore diameter is determined according to coal production, generally 2 to 8 m. Among them, the auxiliary well doubles as the intake well with the largest section; the main well is dedicated to upgrading the coal, and the wind well is used for wind extraction, and the section may be smaller.According to the characteristics of strata, especially the topsoil features, wellbore development can be divided into ordinary and special wellbore methods. Conventional borehole drilling methods do not require pre-reinforcement of the formation. The borehole blasting method is mainly used. After the excavation of a certain height, the reinforced concrete permanent shaft wall is built. When encountering some layers of aquifer, it should be grouted in advance. Grouting holes can be drilled on the ground, and grouting can also be done from the working surface. When the wellbore passes through the drift sand layer, a special drilling method must be used if the ordinary drilling method cannot pass. In eastern China, the use of special drilling methods is quite common. These include the freezing method, the drilling method, the open caisson method, and the curtain method.


The freezing method is to freeze the aquifer around the wellbore by artificial refrigeration method to form a closed cylindrical frozen wall with a certain thickness, and then excavate the wellbore under the protection of the wall. Including the freezing of frozen holes, freezing and excavation of the three processes: to fight the freezing hole in the wellbore diameter is not the proper distance along the construction of dozens of equidistant around the hole, the bottom of the seamless steel pipe down and fixed, and then strata The heat exchange at the freezing station is performed by seamless steel tubes. The ammonia compressor for freezing is completed by continuously circulating brine. The freezing of a few hundred meters thick layer into a frozen soil wall requires the construction of a large-scale freezing station, which can be completed in a matter of months. After the excavation, the freezing work should continue until the wellbore is completely built. Wellbore excavation is the same as ordinary construction methods. Generally, wind tunnels are used for excavation. If borehole blasting is used, the amount of explosives should also be less, so as to prevent the damage from freezing. During the excavation process, the stress and strain of the frozen wall will affect the supporting effect during the thawing process. Therefore, when the whole well is excavated, it is necessary to perform a second permanent support from the bottom up.
The drilling method is a method of drilling a wellbore with a large-diameter drilling rig, including drilling and suspending the sinking well wall. In order to ensure the verticality of the wellbore, decompression drilling is adopted, and the drill bit is in a semi-suspended state. Due to the large diameter of the wellbore, multi-stage drill bits are used, and the required diameter can be achieved after multiple drillings. While drilling, the reinforced concrete or steel plate composite well wall is prefabricated on the ground, step by step at the wellhead, suspended in the whole to a predetermined depth, and then filled with cement slurry.
The open caisson method is to forcibly subside the reinforced concrete wellbore that is poured in the ground using its own weight or its own weight plus additional force. In order to reduce the sinking resistance, steps and edge angles slightly larger than the outside diameter are made in the section of the bottom of the wellbore, and the annular space above the step is supported with thixotropic mud. This method is technically difficult and requires the wellbore to have a uniform texture in order to avoid deflection.

Curtain method is to build a circle of water barriers and concrete walls with sufficient strength around the wellbore to form a curtain, and then excavate and support it under normal construction methods under its protection. The wall thickness is generally 0.8 to 1 m.Another field development method is deviated wells, that is, wellbore excavated from the ground, including the main deviated wells, secondary deviated wells and inclined wind wells. Inclined shaft angle is generally 15 ° ~ 25 °. The main inclined shaft is used for lifting coal, and the ability to use a mine car to lift is relatively small, and the use of a belt conveyor increases the ability. The auxiliary deviated wells are used for personnel and material transportation, and also serve as air intake wells. Compared with vertical wells, the length from the wellhead to the bottomhole yard is several times longer, but the excavation cost is low and the method is much simpler.

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Post time: Sep-29-2019