Tongguanshan Copper Mine Pillar Mining

Copper Mountain copper mine official contact with hydrothermal metasomatic skarn copper pyrite deposit. The ore body is layered, the upper part is relatively large, and the deep part is gradually narrowed and branched. The thickness of the ore is 2~33m, and the inclination angle is 32°~82°. The upper plate is quartz diorite , which is very stable. The lower plate is a quartz corner rock, which is stable to moderate stability, but it is soft and brittle and has poor stability due to the influence of the fault at the contact of the rock. The ore is stable and the copper grade is 0.71%. The surrounding rock contains very little copper. Pyrrhotite, pyrite ores easily oxidized under certain conditions, natural and agglomeration. At present, mining is dominated by the stage mining method and the sublevel caving method. Due to historical reasons, a large number of pillars have been left behind. Since the 1960s, a lot of work has been done on the recovery of pillars, and millions of tons of ore and ore have been produced in various ways, and accumulated rich experience.

Figure 1 shows the mining of the inter-columns and the top and bottom columns of the No. 23 and No. 24 blocks of the Xiaotongguanshan-95m level. The ore and surrounding rock in this section are stable, the inclination angle is 58°, the vertical direction of the mine is arranged, the stage height is 40m, the width of the two mines is 10m and 16m respectively, the width of the column is 8m, and the height of the bottom column of -55m is 10m. It is: (1) Arranging the electric ramp under the inter-column, because the inclination angle is only 58°, two electric eel mines are added to the surrounding rock and used to cut the horizontal rock chamber; (2) from -55m耙Road, -95m stage cutting level and drilling in the rock chamber of the tunnel to drill horizontal or upward deep, medium and deep holes and small holes. YQ-100 type down-the-hole drilling rig for rock drilling and YT-40 and YT-30 rock drilling machines have apertures of 100-110mm and 65-70mm respectively. 40 to 50 mm. The minimum resistance line of the deep hole and the middle hole is 2 to 2.4 m; (3) the column and the top column are blasted once, but the column is advanced. The blasting returned a total of 68,500 tons of ore, and the total consumption of explosives was 30 tons. Due to the stability of the ore rock, there are few cavings on the top, and the level of the ore mining is added. Therefore, the ore loss rate is 2.1% and the depletion rate is 4.2%.

Figure 1 Small copper Guanshan District with a large hole in the deep hole to return to the mining column

1—the lower plate goes to the electric ramp; 2—the electric ramp; 3—the ore; 4—cutting the roadway;

5—rock drilling copper chamber; 6—patio; 7—return airway; 8—transportation lane

Figure 2 shows the situation of multiple ore pillars in two stages of the Laomiao Mountain. The main ore body in this area has a strike length of 70-90 m, a dip angle of 60°-72°, and an average thickness of 13-15 m. The upper plate is a large number of rocks, diorite, f = 8 ~ 12, lower skarn, f = 12 ~ 16, ore f = 10 ~ 12. The ore is very stable. The -55m, -95m and -135m mines have been mined, and the status of the pillars and empty areas is shown in Table 1.

Figure 2 simultaneously mining two stages of pillars

1—mine house; 2—filling; 3—mineral column; 4—electric ramp;

5, 6 - rock drilling chamber; 7 - patio;

Table 1 Occurrence of pillars

Because the ore surrounding rock is very stable, the empty area and adjacent roadway have not been falling for 20 years. In order to accelerate the recovery and prevent waste rock from mixing, the following schemes and steps are adopted:

1. Release the -95m6 mine room filling.

Second, the deep hole once collapsed - 95m, ― 135m two-stage room pillar and the inter-stage column between them, under the protection of -55m bottom column, discharged from the -135m bottom discharge roadway. At this time, the pure ore is basically released, and the rock drilling equipment and the diameter of the hole are the same as the above. The detonation sequence of the top and bottom pillars in the upper stage and the first stage in the same stage is adopted.

Third, the ore will be stopped until only 5m thick, leaving it as a cushion. Then, use a deep hole to collapse -55m bottom column, while using the chamber to blast the top, and release its ore under the collapsed overburden. According to the amount of rock needed to deal with the empty area, six drug rooms are arranged without affecting the stability of the mining roadway and the construction is convenient, among which 1, 2 and 3 are the main drug rooms. The No. 1 drug room is located at the discontinuity of the upper ore body of the -95m5 mine. The minimum resistance line is 23m. The No. 2 and No. 3 drug rooms are located in the surrounding rock of the -95m stage, with resistance lines of 20m and 30m respectively. The distance between the medicine chambers is 18m. The other three are auxiliary medicine rooms, which are located on both sides of the main medicine room in the surrounding rock of the upper plate to overcome the rock clip. The blasting charge of the drug room is calculated according to the unit consumption of 1kg/m ³ . Use the blast hole stripping method to block the drug room roadway (usually 8 to 10 m long), and peel off the blasthole to advance the 5 to 6 section of the drug room. The total mining blasting 139,770 tons of ore, caving Surrounding 41,000 m ^3, goaf filling rate of 40%, to meet the requirements of processing the empty area. The main technical and economic indicators are: mining work volume 9.66m / kt; empty area treatment roadway workload 1.14m / kt; per meter deep hole collapse amount of 12.9t; falling mine explosive consumption 0.42kg / t; secondary crushing explosive The consumption is 0.2kg/t; the ore loss rate is 11.6%, and the ore depletion rate is 18.5%. The direct cost of mining pillar mining is 1.6 yuan/ton; the output capacity of electric raft is 250-300 tons/day; the large-scale output rate is 15-20%. Statistics show that the increase in loss depletion mainly occurs after the collapse of the -55m bottom column (before the ore loss rate is only 7.4%, the depletion rate is 15.2%). Due to the release of ore under the overburden, the large blocks are also concentrated in the later stage of the ore release.