JPH0370078B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention relates to a method for easily and economically cutting out rock blocks for use as building materials, tombstones, and various other uses from bedrock in a mine. .

(b) Background technology Cutting and recovering rock blocks from the bedrock is relatively easy in open pit mining due to the multi-free surfaces and large working area, but in underground mines, hydraulic disking methods have been used up until now. Since this method requires expensive equipment and high construction costs, there has been an urgent need to develop a low-cost method for cutting out rock blocks.

(C) Disclosure of the Invention The present invention proposes an efficient and low-cost method for cutting out rock blocks, and is particularly effective in underground mines. Drilling and opening guide shafts at predetermined intervals, leaving pillars on both sides of the advanced guide shaft, and opening slits along the outer periphery of the predetermined blocks to be cut into the open surface of the rock outside the pillars, The method is characterized in that one or more blast holes are drilled along the back side of the block, and then explosives are exploded in the blast holes.

Embodiments of the method of the present invention will be described below with reference to the accompanying drawings.

(D) Example Fig. 1 is a plan view of the inside of a mine where a rock block is cut out. 1 is a tunnel, 2 is a rock from which a block is cut, and first an advanced guide hole 3 is cut in a direction perpendicular to the two sides of the rock.
excavation is carried out at a predetermined location and a predetermined distance. Both sides of the advanced guide hole 3 are left as pillars 4, and rock blocks 5 are formed from the outside.
I'm going to cut it out.

Therefore, in order to cut out the block 5, first, a slit 6 is cut into the back surface of the block 5 along the outer periphery of the open surface (cutting surface) of the rock 2 from which the block 5 is to be cut out, which is the front shape of the block 5. Open to a depth of . An automatic drilling machine, leg drill, etc. is used to drill the slit 6, and the slit 6 can be formed by continuously making a large number of holes.
(see figure).

Next, a plurality of blast holes 7 are bored from the advanced guide hole 3 side along the back surface of the block 5 in a direction perpendicular to the pillar 4 using a drilling machine. The blast holes 7 need only be drilled to a point slightly beyond the center of the back surface of the block 5 to be cut out, and do not need to be drilled to cover both left and right ends of the back surface of the block. Furthermore, it is not necessary to make the blasting holes 7 evenly over the entire back surface of the block 5, and it is sufficient to explode the explosives 8 at the center of the back surface of the block 5. In the case of cutting out blocks (up to 100 cm square), 1 to 3 holes should be drilled toward the center of the back, and even for large blocks (for example, 100 to 200 cm square), several holes should be drilled near the center of the back.

Therefore, explosives such as black powder 8 are placed in the blast hole 7.
Load and explode. For example, when cutting out a granite block, the amount of gunpowder charge is approximately 30g of black gunpowder.
It is sufficient to equally divide m ³ (block volume) into each blast hole 7.

Due to the gas expansion generated by this blasting, the back surface of the block 5 is cut off from the bedrock 2, and
The block 5 is extruded from the cutting surface. The block 5 may be completely extruded from the cutting surface by blasting, or more than half of the block 5 may be extruded from the cutting surface, and the rest may be extracted by mechanical force such as a forklift. .

In order to facilitate the work of extracting the blocks 5 from the two sides of the bedrock, it goes without saying that the order of cutting out the blocks 5 is not only to the depths of the bedrock, but also to the sides.

(E) Effects of the Invention The present invention is constructed as described above, and the problems of cutting and recovering rock blocks in a mine, such as cutting out the back side of the block and extracting the block, can be easily and instantaneously carried out, making it extremely effective and economical. It is true.

It goes without saying that the method of the present invention is not limited to cutting out rock blocks in underground mines, but can also be applied to cutting out rock blocks in open pits.

[Brief explanation of drawings]

FIG. 1 is an explanatory plan view of a mine showing the procedure for cutting out a rock block according to the present invention, and FIG. 2 is an explanatory diagram showing one process of cutting out a rock block. Explanation of symbols, 1... Mine shaft, 2... Bedrock, 3... Advanced shaft, 4... Pillar, 5... Rock block to be cut out, 6... Slit, 7... Blast hole, 8...
Gunpowder.

Claims (1)

[Scope of Claims] 1. When cutting out rock blocks to be used as building materials etc. from the bedrock in a mine, an advanced guide shaft is excavated at a predetermined location and a predetermined distance in a direction perpendicular to the rock surface of the side wall of the tunnel from which the rock block is to be cut. After opening, a slit is cut along the outer periphery of the rock block to be cut out in the open face of the rock outside the pillar so that the pillar remains on both sides of the advanced shaft. Next, at least one blast hole is drilled slightly beyond the center of the back of the rock block to be cut out perpendicular to the side wall of the advanced shaft, and then explosives are poured into the blast hole. 1. A method for cutting out a rock block from a rock in a mine, characterized in that the block is cut from the rock by charging a charge in equal parts and detonating it in a hole in the back of the block.