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Example of local mining method for steel plate runner in Liucun gold mine (underground mining of rock gold deposit)
Local steel chute ore method successfully in practice leaving the village gold mine, the method can solve the problem on an unstable disk surrounding rock inclined thin mine Shrinkage Method of recovery.
I. Problems in the mining of the ordinary mining method
The main ore body of the Liucun gold deposit is located in a quartz vein (belt) that runs northeast and tends to the northwest. The ore body is a gold-bearing quartz vein with a grade of 3.5g/t, an inclination of 55-75°, and an average thickness of 1.5m. The ore is stable. The upper part of the ore body is the yellow iron shale or the yellow iron shale shale shale, the alteration is strong, the fissure morphological development, the stability is poor, and there is fault mud in some areas. The surrounding rock is moderately stable and partially contains fault mud. From the perspective of the dip angle and thickness of the ore body, the amount of ore that is suitable for mining by the retention method accounts for 60% of the total ore.
Since the mine was put into production in 1988, several ore blocks have been recovered by the method of retaining ore at the bottom of the flat-bottom electric shovel. Due to the instability of the surrounding rock, the large area has fallen, and the recovery is less than half of the height of the ore block. Mining.
The length of the first stope is 40m. With the upper mining, the cracks in the surrounding rock gradually expand and the working conditions of the stope deteriorate. To this end, it is necessary to leave irregular rock pillars in the stope to support the surrounding rock of the upper plate, and install the anchor rod with a length of 1.8 to 2.0 m on the upper plate and technical measures such as strong mining. When the mining area is 16m high, the surrounding rock of the upper plate will fall off a large area, and the stope cannot enter and is forced to stop mining.
In the design of the second stope, in order to avoid the recurrence of the accident in the first stope, the length of the stope was shortened to 15m, and the surrounding rock of the upper plate was still supported by bolts. When the mining room is 20m, the large area of ​​the upper plate will fall off, causing the stope to stop mining.
Later, several mining fields were recovered, but they were not successful. Ore loss and depletion are as high as 50%, and the ore grade is below 2g/t.
Due to the low grade of ore in the Liucun gold deposit, the filling mining method cannot be used. After research, it is improved on the basis of the original retention method, and a new scheme for local mining of steel plate runners is proposed. Through production practice, good results are obtained.
Second, the steel plate slip well retention method test
The basic feature of the new scheme is that one third of the caving ore after each cycle of blasting in the middle of the stope in the middle of the stope is placed in the quarry, and the chute is placed at the bottom of the stope to be loaded, while the remaining three In the second part, the ore is left in the stope, and its function is similar to that of waste rock filling. It supports the surrounding rock and prevents deformation and fragmentation. In order to reduce the moving range of the ore deposit, when a large amount of ore is discharged, it is divided into upper and lower parts. First, the ore in the upper part of the stope is discharged through the upper mining system. After the upper part of the ore is discharged, the lower part of the ore is released through the bottom layer ore discharge system (see Figure 1).
Figure 1 Steel plate slipping method
1—Pedestrian patio; 2—Steel slip mine; 3—Pedestrian well; 4—Upper ore mining structure;
5—bottom mining structure; 6—explosive ore; 7—upper middle section along the vein roadway; 8—upper layer electric ramp;
9—slip mine mouth; 10—external slip mine; 11—extra-pulse transport lane; 12—extraction vein
The test was carried out at the 1505 stope of the 5-line in the -1.5m stage. The section height is 40m, the length of the stope is 30m, the width is 1.5m, the bottom height is 4m, the top pillar is 3m thick, no column is left, and the bottom structure of the flat-bottom electric ramp is adopted. The electric ramp is set on the lower plate, and the spacing of the ore discharge is 5m. One end of the stope is a mining patio, and the other end is a smoothing patio. A steel plate runner is set up in the center of the stope. The upper mining layer is 1.5m high, and the pacing patio and steel plate runners are erected higher than or equal to the mining stratification height. The steel plate runner is fixed at the height of 5m with a bolt to prevent it from falling over a large amount of ore.
The test stop did not use any support during the recovery process. The test obtained the following indicators:
One loss rate /% 4.5
One depletion rate /% 5.6
Total loss rate /% 11.6
Total depletion rate /% 18.2
Production capacity / t·d - 1 50
Recovery cycle / d 45
Large mining time / d 20
The success of the partial ore-retaining method of the Remaining Steel Plate has better solved the problem of mining the steeply inclined thin veins with unstable surrounding rock. The deposit ore remaining in the stope plays an effective supporting role for the surrounding rock, ensuring the safety of the stope and preventing the surrounding rock from falling off; the local mining method of the steel plate runner improves the mining of one third of the ore. Grade; divided into two parts of the upper and lower part of the ore, can effectively reduce the amount of surrounding rock and the amount of ore that can not be released in the lower plate, reducing the secondary loss and depletion of ore.