Test of the cutting and retaining method of the Chuanshanzi gold mine (underground mining of rock gold deposit)
ZHUANSHANZI gold mine tested scarps Shrinkage Method, successfully tested the method to create a new mining methods and mining technology as rock gold mine in China. This new method is suitable for extremely thin and thin veins with moderately thick ore veins with a thickness of 0.4 to 0.7 m.
I. Geological conditions of veins and mining conditions of experimental ore blocks
The Chuanshanzi gold deposit is a medium-temperature hydrothermal gold-bearing sulfide quartz vein and altered rock type deposit with a pulse thickness of 0.3-0.5 m and a dip angle of more than 60°. The vein shape is relatively stable and the ore is moderately stable. The deposit water and geology are simple.
The test stop was selected in the No. 27 vein four-stage 405. The ore length is 43.5m, the inclination angle is 62-75°, the stage height is 37m, the average thickness is 0.43m, the ore weight is 2.8t/m 3 , the average grade is 15.33g/t, and the looseness coefficient is 1.5.
There is a small fault after mineralization in the ore block, the fault distance is not large, the structure is simple, the ore contains less sulfur, does not agglomerate, and there is a small amount of water at the vein fault.
2. Experimental study on the method of cutting the wall and retaining ore
In contrast to the wall-filling method, the method is to leave the ore in the stope, support the surrounding rock, and then remove the rock from the waste rock well. Therefore, it is different from the mixed mining and retention method, and the mining rate is small, which reduces the depletion rate.
The mining block is very simple. One side is a pedestrian ventilation patio and the other side is a smooth road patio. A waste rock slide is constructed in the center of the stope (see Figure 1).
Fig.1 Arrangement of mined ore retaining method
1—designing artificial top columns; 2—reserving rock filling wells; 3—top pillars; 4—filling wells in pillars;
5—Electric stern pulley fixing device; 6—pad; 7—stubbing; 8—electric shovel winch;
9—Mao Shijingjing; 10—Shun Road Pedestrian Well; 11—Lifting Funnel; 12—Artificial Bottom Column
In order to reduce the loss of ore, an artificial bottom column and a partial top column are formed by reinforced concrete, and an iron funnel is arranged in the artificial bottom column (see Fig. 1). The top column is 3m high, and a patio is built in the center. It is used to treat the goaf into the waste rock, and each side is filled with a filling well for constructing the artificial top column.
The mining is carried out from the central waste rock well to both ends. The length of each section is twice collapsed to the ore vein, which is 0.6m wide and has a wall-cutting blasting. The width of the cut wall is 0.3m and the total width of the mining width is 0.9m.
The ore is collapsed and the ore is controlled at 0.25m and left in the stope. Before the wall blasting, the old transport tape and straw mat should be laid on the ore surface. The collapsed rock was transported to the central waste rock well using a 7.5 kW small electric raft. In order to facilitate the rock, the stope forms a "V" shape with a dip angle of 3 to 5 degrees.
The waste rock well is 0.5m high per section and is welded with 2~3 iron plates, ф0.7m. In order to prevent plugging, a 0.2m 2 × 0.2m 2 sieve was placed on the waste rock well.
With the mining on the pick-up, gradually increase the waste rock well and the smooth road patio.
There are 10 workers in the test stop, including 4 rock blasting blasters, 1 electric smasher, 2 pillar workers, 2 Pingchang workers, and 1 masonry. Four shifts are implemented; two shifts in the stopway are half-cutting and one-off rock drilling and one rock drilling and rocking; one class of pedestrians, paving and rock blasting; one shift and the waste rock, put Pull the cart to the shaft.
The test stop has been tested since the end of July 1992 and has not been harvested yet. After entering the normal cycle operation, the average daily mining height is 0.5m, the ore deposit is 35~40t, the actual operation is 73d, and the ore is 2948t.
After the mining room is finished, the artificial top column is cast as designed. A total of 38 days of large-scale ore mining, washing the stope with high-pressure water, a total of 3020t ore, the average production capacity of the stope 27.2t / d.
After the end of the mine, some of the waste rock is filled and the goaf is partially treated.
Third, the evaluation of the method of cutting the wall and leaving the mine
Compared with the wall filling method, the wall cutting method reduces the amount of rock cutting, thereby reducing material consumption and reducing operating costs. It is calculated that the material consumption of the wall-filling method is 1.41 times that of the wall-removing method, and the mining operation cost is 1.68 times.
The main technical and economic indicators obtained by the method of cutting the wall and retaining minerals:
Mining ratio /m·kt - 1 18.06
Production capacity / t·d - 1 27.2
Mining ergonomics / t · work class - 1 4.04
Ore loss rate /% 1.90
Ore depletion rate /% 33.50
Excavation grade /g·t - 1 5.49
Mining cost / yuan · t - 1 16.66
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