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Fankou lead-zinc mine with VCR method mining column
The ore body is complex in shape, with branching and compounding, more interlayers, and the production is controlled by structure. Mining sub Venus Ridge, Shiling Shiling and South ore body. Jin Xingling ore body length 400m, angle 40 ~ 68 °, a thickness of the ore body 20 ~ 50m, 100m thickest; massive lead zinc ore pyrite, grade 18% ~ 20%, ƒ≥8, solid medium. The Shiling ore body has a length of 800m, a dip angle of 15 to 70°, a thickness of 30 to 60 m, an ore ƒ=10 to 12, and good stability; the lead and zinc grades are 15% to 20%, and the highest is 33%. The conditions of the Shilingnan ore body are similar to those of the Shiling ore body. The surrounding rock of the top and bottom plates is limestone with ƒ=8～12, which are relatively stable, and the filling and the argillaceous limestone of the top and bottom of the local ore body are inferior in strength and stability. The mines are generally arranged vertically, with a width of 7 to 10 m, a column width of 7 to 8 m, and a top column height of 6 to 13 m. The mine is mainly used for horizontal stratified tailings and gravel cementation filling method, and some of the mining methods are used for post-harvest filling and recovery. In 1981, the VCR method was used to test the column. Taking 3~4 and 7~8 columns as examples, the column width is 8m and 6.7m respectively, and the three-month-old strength of the two sides of the filling body is 4.556~9.4MPa on average, and the self-supporting property is better. The structure of the nugget is shown in Figure 1. A rock drilling chamber is arranged on the upper part of the ore block, and the chamber is 4.5 m high and is maintained by a bolt metal net. 3 to 4 columns with a funnel bottom structure; 7 to 8 columns are flat bottom structures. They all use the scraper to mine, and 7 to 8 columns use the remote-controlled scraper to finally recover the residual ore in the empty area. The height of the bottom is 3m and 7.5m respectively.
Figure 1 Fankou mine VCR mining 3 to 4 columns
1—anchor and metal mesh; 2—rock drilling chamber; 3—large diameter deep hole; 4—flat bottom sulcus; 5—outflow sluice;
6—mineralization route; 7—recovery boundary line; 8—disintegration layer line; 9—column stone; 10—mine pillar outline
The self-drilling chamber was drilled with a ROC-306 type down-the-hole drilling rig with a diameter of 165 mm and a parallel deep hole, and the bottom layer was pulled straight. The blasthole meshes are 2.7 x 2.7 m and 3 x 2.05 m, respectively. In order to protect the filling body, the distance between the side hole and the filling body is 1.3 to 1.5 m, which is about 8 times the diameter of the medicine package. Use high-density, high-power, high-detonation, low-sensitivity emulsified spherical packages to blast from bottom to top (3 to 4 columns) or multiple layers (7 to 8 columns). In order to increase the degree of coupling, the diameter of the package is increased to 150 mm. During layer blasting, each layer is 3.13~3.93m thick, and the last layer is 9.6m thick. When multi-layer blasting, blasting 2~3 layers each time, using blasting in the hole and micro-differential between holes, layer thickness 6.4 to 10.7m.
Compared with single-layer blasting and single-layer blasting, the number of blasting in the stope is reduced, the collapse efficiency is improved, and the recovery speed is accelerated. The mine mining speed, production schedule and specific conditions of the stope can be used to flexibly grasp the amount of each collapse.
Under normal circumstances, there should be planned ore discharge, so that the stope retains a certain amount of ore to support the surrounding rock and the filling body. In order to prevent the collapse of sulfide ore from self-heating, agglomerate suspension and SO 2 toxic gases, non-quantitative enhanced ore-mining is used to reduce ore accumulation time. Practice has proved that the filling body is not caused to fall. The average sunrise mine of CT-1500 scraper is 518t (3~4 columns) and 783t (7-8 columns). The average working efficiency of the residual ore in the empty area was recovered by the YK-1 wireless remote-controlled scraper to 137t (transport distance 35m).
After the end of the mine, the mining area is filled. First fill the bottom of the column with cemented filler for 3m, then fill with water sand or waste rock. The 7-8 picking site is used as a waste stone silo.
In order to prevent high-oxidation self-heating agglomeration of high-sulfur ore, the following measures were taken: (1) strong mining and strongening, shortening the residence time of ore in the stope; (2) loading 2.5 kg of lime powder in the lower part of the medicine package To mix the lime powder raised during blasting with the dust, to suppress and slow the oxidation rate of the ore; (3) to prevent the excessive accumulation of the sulphur dust during the blasting process, the duration of the whole layer detonation is controlled within 200ms; 4) Prevent the leakage of explosives from the drug pack and contact with the ore; (5) Block the bottom of the hole before charging, reduce the upward flow of the stope, and seal the hole with a cork to prevent toxic gas from entering the upper working chamber.
After taking the above comprehensive measures, the 3~4 and 7~8 stopes are safely collected. Other mining sites have achieved good results after taking enhanced mining measures. The main technical and economic indicators are shown in Table 1.
Table 1 Main technical and economic indicators
Indicator name
Quantity
Remarks
Rock drilling efficiency (m / shift)
Bomb hole collapse per meter (t)
Explosive unit consumption (kg/t)
Of which: falling mine
Secondary crushing (kg/t)
Ore bulk rate (%)
Working productivity of working face workers (tons/work shifts)
Average production capacity (t/d)
Mining workshop cost (yuan/ton)
Of which: tunneling operations (yuan/ton)
Mining operations (yuan/ton)
Filling operation (yuan/ton)
Ore loss rate (%)
Ore depletion rate (%)
20.2
24.8
0.28
0.26
0.02
1.31
21.2
61
34.53
3.31
6.0
5.0
2.38
3.40
1. The loss of ore and the depletion index, due to the inaccurate measurement of the ore, there is no effective method for the measurement of the goaf, and the mine affects the accuracy of the indicator.
2. Workers' productivity in working face includes workers who rock, blast, mine and mine
3. The ore block rate is calculated according to the large block of ore block size greater than 450mm.