Qingchengzi lead-zinc mine explosion force moving section mining house mining method

The ore is mainly composed of galena and sphalerite. The average grade: Pb2.33%; Zn2.01%, weight 3.26t/m ³ , relatively stable, f=8~10.

Footwall clayey sedimentary metamorphic mixed qualitative Granulite (potassium granite), hard, f = 12 ~ 14, but the local area triangle joints are well developed, and veins at the contact, a layer of 0.5 1.7m thick sillimanite quartz Mica - The schist, joint development, unstable, f = 6 ~ 8. The direct roof of the ore body is 2 to 10 m thick graphitized dolomite marble, f=6-8, which is not stable and easy to fall or fall. The old top is a horny schist, fine grained crystal structure, sheet structure, sericitization and silicate, which is harder, f=10~12, and has good stability.

The stage height is 30m. According to the reasonable transportation distance of the explosive force, the stage is divided into two segments with a height of 15m. The segmentation is divided into each mining unit with a length of 32 m along the strike. Place 2 to 3 rock drilling patios in it (see Figure 1).

Figure 1 Explosive force migration segmentation method

1-rock drilling patio; 2-ditch; 3-cutting lane; 4-bell neck; 5-hopper wearing;

6-electric ramp; 7-mining chute; 8-transport lane; 9-electric chamber; 10-side walkway;

When the ore body continuity is good and the upper plate is stable, a temporary inter-column column is left between each mining unit. In order to recover the temporary pillar, the following technical measures are taken: when the mine is harvested to the last landing step (equivalent to the top column), the medium-deep hole on one side of the column is deepened, and the tunnel is moved from the trench to the intermediate column. Drill a deep hole (can be pre-punched), and blast once in the last step. In the poor stability of the upper plate, the section height is appropriately reduced, without leaving the column, continuous mining, first picking odd-numbered mining units, and even-numbered mining units as temporary inter-columns, leaving to the last falling step No mining, as a temporary top column, when the even-numbered mining units are returned to the last falling step, they will collapse together.

The bottom structure of the trench is adopted. Each section has a mine shaft and a pedestrian well connected to the stage transportation level. The size of the segmented electric ramp is 2×2m, the bucket size is 2×2m, the bucket neck size is 1.5×1.5m, the bucket neck height is 4m, and the funnel spacing is 5～7m.

The position of the cutting lane in the surrounding rock of the lower plate should be as shown in Figure 2. A corner of the roof of the roadway should be connected to the contact surface. When the hole is made, the hole angle needs to reach 55°. In order to dig the trench, a small vertical trough of 4 m width is generally formed in the center or side of the mining unit, and then a fan-shaped medium-deep hole is arranged in the center of the cutting lane, and the row is blasted along the row.

Figure 2 Reasonable position of the cutting lane

1-cut roadway; 2-electric roadway

The section of the rock drilling patio is determined by the rock drilling equipment used, which is 2.2×2.2m when using the 01-38 rock drill and 2.7×2.7m when using the YG-90 rock drill . In order to reduce the loss of ore near the bottom plate, the patio should be cut into the surrounding rock from 0.4 to 0.45 m. During construction, the direction of excavation should be strictly controlled to ensure that the patio is perpendicular to the ore body.

At the time of mining, a fan-shaped deep hole perpendicular to the ore body is drilled in the rock drilling patio, with a hole diameter of 65 mm, a minimum resistance line of 1.0 to 1.5 m, and a hole bottom distance of 1.3 to 2.2 m. In order to reduce the large size and ensure the flat plate is flat, the front and rear rows of holes should be staggered. The bottom hole is larger than 5°. The use of homemade ф 55 ~ 60mm ammonium explosives, the charge factor of 75%. The amount of blasting is determined according to the volume of the gully, usually five rows of blastholes. Use a millisecond electric detonator and a detonating line to jointly detonate or use a non-conducting squib. The ore was transported with a 14kw electric raft.