At the end of several medium-sized mines in Liaoning Province, there have been movements and subsidies on the surface. Some have damaged the surface of the mine. China copper mine mouth as the original hoist is undermined. Some have affected roads and civilian housing, and even affected the wellbore and damaged it. Therefore, in the mine design, the impact of the movement of the rock formation in the goaf on the location of the main roadway must be given enough attention.
The extent of caving and movement on the upper surface of the goaf is called the caving zone and the moving zone (Fig. 7-22). The angle between the boundary of the goaf and the edge of the surface collapse zone and the edge of the moving zone and the horizontal plane are called the collapse angle and the movement angle, respectively.
The size of the caving angle and the moving angle are directly related to the physical and mechanical properties of the upper strata of the goaf, the development degree of the bedding and joints, the hydrogeological structure, the mining depth and the mining method used, usually between 30o and 80o. between. Each rock formation and geological condition has its own caving angle and moving angle. Generally speaking, the moving rock of the ore body is on the moving angle of the lower rock, and the moving angle of the two ends of the ore body is the largest. Table 7-6 shows the common rock movement angles.
The area within the surface movement zone is a dangerous area, and the pioneering works or permanent structures (structures) placed in the moving area will be destroyed. In order to ensure safety and avoid losses caused by surface movement, the main development roadway and other structures to be protected should be arranged outside the moving range and maintain a certain safe distance from the boundary of the surface moving belt. The safety distance is related to the protection level of the building (structure). According to the regulations, the safety distance of the Grade I protection building (structure) is 20m, and the safety distance of the Class II protection building (structure) is 10m. The protection level of various buildings (structures) in the mine is shown in Table 7-7.
The selection of various rock movement angles should be based on a variety of relevant information, and at the same time refer to the situation adjacent to the rock. In the design, the main choice for the development of the roadway location is based on geological prospecting and other materials. At present, the geological data of some small mines are not so accurate due to the incomplete engineering. It is necessary to arrange the shaft engineering according to the actual situation, especially in the place where the terrain is relatively flat. Due to the thicker Quaternary rock formations, there should be room for the movement angles of the various rock formations and the safety distance of the ground, otherwise unintended consequences will result.
The delineation of the moving belt is based on the geological cross-section of the main axis perpendicular to the ore body and the geological longitudinal section along the strike, starting from the lowest level of the ore mining (when the ore body is irregular, from the ore body, The protruding part of the lower plate starts from the different moving angles of the rock layers (the upper, lower and end parts of the ore body), and the straight line intersects the ground respectively, and then the upper, lower and inner ends of the ore body are intersected. Connect one by one to form a closed circle on the topographic map, which is the surface movement belt to be delineated.
If due to certain conditions, the main roadway or important building (structure) can only be placed in the rock moving belt. For safety reasons, it is necessary to leave a security pillar or a cement filling method with better roofing effect.
The so-called security pillars are the ore that is not mined within the service years, and the main development roadway and surface construction (structure) within the scope of the main roadway and other surface structures (structures). The body of the ore. The security pillar can form a safety protection belt that does not move inside the rock moving belt, so that the structure located inside is not affected by the rock movement.
In the mine design, the layout (location) of the main development project should be based on the deepest level of the mining site. If the deposit is jointly developed or staged, and the deep geological data (mainly referred to as the ore body element) is well understood, no matter what scheme is used in the second phase of development, the depth should be considered when determining the location of the upper development project (or The impact of the second phase of the project). When the deep ore body is not closed, but the geological conditions are relatively small, comprehensive analysis and research should be carried out. That is, the designer should extensively investigate the scale of the same type of deposit in Caijing, study the occurrence of deep ore bodies, make rough ore movement angles according to the ore body that may be extended, draw the movement limit, and then arrange the surface. Engineering and upper development projects. Only in this way can the mine not cause accidents due to rock movement throughout the production process.
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