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(1) Stage height - the bottomless column caving method is mostly used to return the extremely inclined thick ore body with stable ore. Therefore, the stage height is relatively large, generally 60 to 70 meters. When the ore body is inclined at a slower angle, the occurrence is irregular, and the ore rock is not stable enough, the stage height can be smaller. Because when the rock is not stable, it will increase the maintenance cost of the mine, equipment and ventilation wells. When the ore body is inclined slowly, the lower sections will lead to the chute, the communication path of the equipment well will increase accordingly, and the transport distance will increase accordingly. If the fragile ore and the chute pass, the amount of fine ore will increase. Therefore, when the mining conditions are unfavorable, the stage height is somewhat lower.
(2) Stage transportation lane layout—For the bottomless column method, the stage transportation lane is mostly arranged outside the vein, and its purpose is to be used as a return air passage when the next stage of mining is convenient. At present, there is also a method of pipe ventilation in the foreign countries, that is, the pipeline is always passed to the working surface to solve the problem of return air. In this case, the transportation lane can also be arranged in the vein.
(3) Section height—The height of the section is related to various factors such as transport equipment, rock drilling equipment and mining requirements. The height of the segment is large, which can reduce the workload and reduce the procurement cost. However, it is limited by the workload of rock drilling equipment, rock drilling and blasting technology, and the loss of depletion indicators during mining, which in turn makes the segment height not too high.
According to the existing rock drilling equipment in China, when the hole depth is greater than 12 to 15 meters, the rock drilling efficiency drops sharply, and at this time, accidents such as pinching and breaking brazing are likely to occur, and the deep hole is scrapped. (Temple iron ore proved this problem) large height segments, further increasing the difficulty of pulling the cutting slot (easily opened), while the vertical groove is easy to produce or easy to leave blasting cap.
The section roadway can't be too low. When it is too low, it not only increases the mining workload, but also affects the stability of the mining roadway. When the ore body is irregular, if the segment is too low, at the edge of the ore body, the upper and lower segments are difficult to be arranged in a diamond shape, and the segment height should not be too high. (In order to reduce the workload of mining, reduce the depletion of losses, solve the problem of ventilation in single-head roadways, and adapt to the needs of high-efficiency mining equipment, the program of high-segment dual-channel is currently being tested in China.)
According to the specific situation of using the sublevel caving method without bottom column in China, the segment height can be between 9 and 15 meters, and the actual use is 9 to 12 meters, but 10 meters is better. (Temple, Golden Ridge has 10 m).
It is advisable to determine how high the height of the segment is. In fact, there are still issues to be studied and summarized.
In the figure stage, the transportation lane selection: there is no advantage in placing this position. There are many advantages in the layout of the upper plate boundary: 1 can be prospected; 2 when the next segment is taken, it can be used instead of cutting the roadway. Gongchangling Iron Mine is to open two veins along the veins in the lower coil, also in a circular transport. When the thickness of the ore body is not large, it is also possible to open only one path along the vein and distribute it outside the lower disk.
October 03, 2024