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Overhanging treatment in mining of Hami gold mine by retaining ore method (underground mining of rock gold deposit)
In mining ore adoption leave, Hamilton gold mine to explore a number of effective treatment experience hanging arches.
I. Reasons for the occurrence of suspended arches in the mining method
GOLD HAMI size of more than 150 gold quartz veins, mostly lenticular, branched compound, expansion and contraction, a phenomenon pinch reproducing like. The veins are nearly parallel to each other with a spacing of 20 to 100 m. The largest vein is 157m long, the minimum length is only 10m, the maximum thickness is 4.8m, the minimum thickness is only 0.3m, the maximum extension is 240m, the vein is 250~270°, and the inclination is 65-85°. The surrounding rock of the upper and lower plates is a reddish-brown alteration zone (yellow iron shale lithology, chlorite petrochemical), about 1m wide, and it is a flash granite .
In the past five years of production, the ore method has been applied to the ordinary funnel structure. The funnel spacing is 5m, the specification is 1.2m×1.2m, the height of the bottom column is 5m, the pitch of the patio connecting track is 5m, and the stage height is 40~60m. The length of the nugget is about 40m, and it is determined by the length of the vein. When it is more than 90m, it is divided into two ore blocks. The width of the mining is 0.8 to 1.2 m. Due to the complex shape of the ore body, the mine has a turn change in the direction and tendency.
In the mining method of retaining ore, the most prominent one is the problem of ore suspension in the ore mining (less local mining, a lot of mining). According to the analysis, the reason for the ore suspension is:
(A) into the surrounding rock ore caving caking properties, such as yellow phyllic, sericite, chlorite, Wong sandwich filling cracks in its surface, these crush rock and fissure fillings are more Great adhesion.
(2) The mining house is narrow and narrow, and its shape is changeable. The ore in the changed part is very easy to block and squeeze.
(3) The caving ore is stored in the mine for a long time.
(4) Rock drilling water and mine water, so that the ore has a certain humidity, which provides favorable conditions for the formation of agglomeration.
Second, the type of ore suspension arch and its treatment method
The cantilever arches appearing in the mine can be divided into three types: (1) a higher wall is built above the funnel ridge, similar to a pier, and the upper ore is formed into a cantilever, similar to a bridge body, called a "bridge pier arch" (2) There is no thick wall in the funnel ridge. The ore above the funnel forms a cantilevered arch, called the “bridge overhanging archâ€; (3) there is only a solid wall stacked above the funnel ridge, and there is no overhanging arch above the funnel, which is called “dock archâ€.
Different treatment methods are adopted for different overhanging arches:
(1) Vibration method. Regardless of the type of cantilever, as long as the arched surface is close to the funnel opening, a small amount of explosives can be used, and it can be blasted from the leak to the upper part of the funnel, sometimes requiring multiple vibrations. When you put the medicine pack, the movement should be agile and careful, and people are not allowed to drill into the funnel. If the arch is too high, it can be used on the heap to destroy the arch.
(2) Blasting law. The dangling arch is stronger and the blasting method is used when the vibration method does not work. The explosive package is wedged onto the bamboo pole and sent to the key part of the suspended arch or the wall, and the explosive charge is used to treat the overhang arch which is closer to the funnel opening. If the overhanging arch is too high, it should be blasted from the patio link on both sides of the mine house with a bamboo pole bundle explosive charge to treat the above three types of overhang arches.
(3) The wedge drilling method. If the overhanging arch is too high from the funnel opening and close to the surface of the heap, the person is standing on a long ladder on the surface of the ore, wedged down with a steel pipe or drilled down with a rock drill, wedged or drilled. The holes are irregularly dense to destroy the collapsed structure of the heap and cause it to collapse.
(4) Water flushing method. This method is safer and easier. Water rushing is the easiest to overcome the cohesiveness of the ore and destroy its agglomeration. This method can be used for all three types of overhanging arches. It can be rushed from the funnel or from the surface of the contact or heap.
(5) Rocket tube. This method requires empty and vertical space to prevent the launch of the rocket launcher. This method does not work if there is room for curvature or narrowness. The disadvantage of this method is that the cost is too high.
(6) Changing the structural parameters of the mine. At the level or inclination of the bend, a smooth and smooth transition section should be formed during rock drilling and blasting to facilitate ore flow. The ore that has collapsed is required to be evenly broken. When there is a large block, the secondary crushing is carried out in time to make the ore have good fluidity; the spacing of the funnel is reduced from 5 m to 3.5 to 4 m, and the neck is enlarged from 1.2 m × 1.2 m to 1.4 m. ×1.4m, the height of the bottom column is changed from 5m to 3.5m; the width of the funnel ridge and the height of the funnel neck are reduced; the pitch of the patio is reduced from 5m to 4m, which is beneficial for handling the arch or reducing the number of occurrences of the arch.