Example of underground mining-room and pillar mining method in Yanjin deposit (Xiangxi Gold Mine)

The gold ore deposit their Western conditions, using a room and pillar mining method

First, mining technical conditions

The genetic type of the deposit belongs to the medium-low temperature hydrothermal filling quartz vein deposit, and the ore-forming hydrothermal fluid is filled along the interlaminar fracture to form the vein. According to the vein shape, it is divided into three types: interlayer quartz vein, joint quartz vein and mesh quartz vein. The application of the room-column mining method is the reticulated quartz vein ore body. The mining conditions are: the ore body thickness is 3~10m, the average is 4.5m; the ore body inclination angle is 20°~30°; the ore is hard and stable, f=8～ 12; the surrounding rock of the top and bottom plates is slate and altered slate, which is unstable to moderately stable f=4~7; the contact surface of the ore is obvious, easy to separate and easy to identify; the gold content of ore is 3~5g/t; alteration The surrounding rock contains 2~3g/t of gold.

Second, mining method structure and mining cutting

The nugget is 40 to 80 m long along the strike, and the vertical height is equal to the stage height of 25 m and the oblique length is 55 to 60 m. The ore is divided into several mines and pillars. The mine room is 8m away, the size of the pillar is generally 3m×4m, the spacing of the pillars is 5m along the inclined direction, and the net span of the mine is 5m. There is a bottom column at the bottom of the nugget. The bottom column is 5~7m long and is recovered during the next stage of recovery. Do not leave the top column. The mining method is shown in Figure 1.

Figure 1 Xiangxi Gold Mine Pillar Mining Method

1—Picking the patio; 2—bottom column; 3—stage roadway; 4—salt winch chamber; 5—cutting alley;

6—mineral column; 7—external roadway; 8—mine slip; 9—cross lane; 10—upper stage roadway;

11—Recovering the blasthole; 12—cutting the patio

The mining and cutting work includes digging the mining block on the two sides of the quarry, and arranging the transporting alley in the surrounding rock of the floor, and driving the mine to the mine. Digging and cutting the roadway along the bottom of the ore body in the upper part of the ore-boring shaft. In the bottom column, the side of the mine is located at the side of the ore-boring well, and the boring and twisting chamber is digged along the central axis of the mine.

The bottom of the mine starts from the intersection of the cutting patio and the cutting alley. The height of the bottom is 2~2.5m. The width of the lowering is equal to the net width of the mine. The length of the bottom is pulled in the oblique direction. According to the stability of the ore, the bottoming is adopted. Or pull the bottom to the full length of the mine. Each segment is generally 10 to 20 m in length when segmented. The bottom is made of shallow eyes, and the sides of the cutting patio are stretched toward each other. Pull down the ore that is taken down, part of it is powered out, and a part of it is left on the bottom plate, so that it can be operated on the pile during mining.

Third, mining work

(1) Falling mine

When the thickness of the ore body above the bottom space is less than 3m, a shallow-eye mining is used to collect the full thickness; if the ore thickness is greater than 3m, the layered ore is used. When the stratified ore falls, the working face of the mining face is in the shape of a step, and the lower step is taken back to the upper step of 3~4.5m.

The 7555 rock drill is used for rock drilling. The blasthole parallel to the bottom space is inclined along the ore body. The blasthole is arranged in the shape of plum blossom, the depth of the eye is 2 to 3 m, and the minimum resistance line is 0.8 to 1.2 m.

(2) Mining

The mining face is mined with 30kW electric raft, and the ore is loaded into the mine car of the floor transportation lane through the concentrating funnel. After the mine returns to a large amount of mines, the floor is cleaned to recover the fine ore.

(three) roof management

Mainly rely on the pillars on both sides of the mine to maintain the roof. If there is a fault in the mine mining or if the roof is partially unstable, leave the temporary pillar or reinforce the roof with anchors. Pay attention to the observation of the top plate during the operation and deal with the loose stone in time.

Fourth, technical and economic indicators

The main technical and economic indicators of the Xiangxi gold mining room column method are shown in Table 1.

Table 1 Main technical and economic indicators of the Xiangxi gold mining house column method

V. Evaluation

When the network of the Xiangxi gold mine was used to mine the reticulated veins, the original method of cutting the wall was used. The ore body was thick, the source of filling was difficult, the safety was poor, the labor intensity of the workers was high, the productivity was low, and the cost was high. Increased the production capacity of the ore block, reduced the manual labor of the workers and reduced the mining cost.