Cutting work of shallow hole retention method

  (1) The purpose of the cutting work - it is to create a free face for the formal mining work.

(2) The contents of the cutting work - including:

1 Digging the bottoming roadway to form a bottoming space,

2 Dig the funnel neck, on the basis of the opening of the bucket, the funnel is opened to form a trumpet shape for the purpose of mining.

3 Generally, one is drilled every 5-7 meters along the strike. In order to reduce the workload of the flat field, the funnel should be placed on the lower side of the ore body as much as possible to reduce the workload of the flat field. The height of the funnel neck is generally 1.0-2.0 meters, and the slope angle should be above 45°.

4 The height of the bottom is generally 2 - 2.5 meters, and the width of the bottom should generally be equal to the thickness of the ore body. For thin and extremely thin veins, the width should not be less than 1.2 meters to ensure smooth ore discharge.

5 Pulling and missing work are often linked to construction.

(Such as some mining iron ore Gongchangling is first opened bottom, and then split drain, since the bucket is split neck drain drill up construction method).

(3) Cutting method

1) The method of thinning the bottom of the vein. (ie the bottom structure of the artificial bottom)

For thin veins, the bottom structure of artificial false bottoms is widely used in mines. At this point, the cutting work is relatively simple, the specific construction method is as follows:

1 In the stage transport lane, hit the vertical blasthole

The hole depth is 1.8-2.2 meters, and all the holes are blasted once.

2 After blasting the first blasthole, stand on the ore heap and lay a second blasthole with a hole depth of 1.5-1.6 m. Then transport the first collapsed ore and set up artificial false alleys and wood. funnel. Lay a layer of wood, grass mats and other elastic things on the false alley.

3 Blasting the second blast hole, the fallen ore releases part of the ore from the funnel, and then flattens the working surface, and the bottoming work ends.

2) The method of pulling the bottom of the bottom without pulling the bottom

This method is suitable for the condition that the thickness of the ore body is greater than 2.5-3.0 meters. The specific construction methods are as follows:

1 On the side of the transport lane, at the inclination of 40°-45°, the first blasthole is drilled. The height of the lower blasthole is determined by the height of the transport equipment (mine truck, locomotive).

The upper blasthole is on the same vertical plane as the rail on the funnel side on the top corner of the transport lane.

2 After the blasting of the blasthole, stand on the side of the heap at a slope of 70° and hit the second blasthole. After blasting the blasthole for the second time, the ore is transported away, and then the workbench is set up. The third blasthole, and the hopper is installed, and finally blasting, the third blasthole is collapsed, and the ore is released from the funnel. Then continue to play the fourth blasthole. The height of the funnel neck after blasting is 4.0-4.5 meters.

(At this point, the height of the horizontal top plate is reached)

The leakage half shape may be a square shape or a circular opening.

3 At the upper part of the funnel neck, the blasthole is drilled around at an angle of 45° to enlarge the neck of the bucket, and finally connect the adjacent bucket necks, and at the same time complete the work of pulling the bottom and leaking.

3) Pulling the bottom of the road to pull the bottom leakage method

This method is applied to ore bodies with a large thickness. The specific construction methods are as follows:

Dig up the funnel neck from the side of the transport lane, and dig a 2m high, 1.2-2.0m wide down-draw flat from the upper part of the bucket neck, and then open it to the main ore body boundary, while pulling the bottom level Tilt the blasthole downwards or upwards from the neck, and expand the upper flat neck or flared funnel.

According to this method, some mines are not convenient in construction, and the following methods are used for excavation.

It is directly into the transport lanes into the two shots (more than 2 meters), then dig up the 3-4 guns vertically, open the bucket neck, install the funnel gate, and open the bell mouth. When leaking, most of them are shot from the bottom up (the bottom road should be boring first).

The bottom can also be deep-hole bottomed, which is highly efficient. However, it is not always easy to form a relatively regular surface. The advantage of shallow hole bottoming is that it can guarantee the specifications. However, the labor efficiency of the shallow hole bottom is relatively low, and the bottom speed is slow. At present, many miners, most of them use the shallow hole method to dig.

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