SU894197A1 - Pillar excavation method - Google Patents

Description

(54) METHOD FOR EXTRACTING PULTS

I

The invention relates to the mining industry and can be used in the underground mining of flat and inclined ore deposits.

There is a method of excavation of the pillars, the state, s, i in the next, it is. In the rocks of the soil of the developed space, workings under pillars are made. The roof of the development is drilled with ascending wells to intersect the soil with the soil and explode. The rear wall, under which the crowd is blown up, and the rock, loses its support and, under the action of the force of its own weight, separates from the roof of the worked-out space and sinks into the cylindrical chamber formed. From the development of the pillar remove one of the known methods 1.

The disadvantage of this method is the very high volumes of rock work and, consequently, the significant costs of extracting ore from supporting pillars, as well as high ore losses. This method is acceptable for the development of pillars of considerable size.

The known method of excavation of the pillars, including the drilling of the pillar by parallel wells at the border with the zone of collapse, its destruction and the cleaning of the destroyed pillar pipe 2.

The disadvantages of this method are the relatively large losses and dilution of the ore.

The purpose of the invention is to reduce losses and dilution of ore.

The goal is achieved by pilling the pillars in the upper and lower parts of it, then tightening the pillars on the pillar, wetting the walls of these wells.

10 and transport it by means of machines and cushions into the goaf with stable pillars.

FIG. 1 is a schematic representation of a method for removing pillars; in fig. 2 -

15 pillar extraction circuit.

The entire pillars 1 of a recoverable row, located at the boundary with the zone of collapse, is drilled on the bases with parallel contiguous wells 2, mainly along clayey layers 3. Filling

20 can be made ahead of several rows. In this case, the effect of artificial compliance of the drilled pillars appears, which leads to a decrease in the reference pressure on the columnar pillars in the work area. In the pillars 1, anchors 4 reinforce the straps 5, which hook onto the mining machines 6 (loading-hauling or dump trucks).

After wetting the walls of the boreholes 2, the rear sight 1 with the help of the machine and the machine is cut off from the roof and soil, and transported to a safe place, which is protected by resistant pillars, which take the main load and destroy it by one of the known methods. The load on the recovered sill with an area of 15–20 m according to special measurements is about 3000 tons. Removing is counteracted by the friction force on clay interlayers in the places of the drilled wells, the value of which depends on the load, the weight of the rear sight and the coefficient of friction. The sign of the coefficient of friction decreases sharply with the moistening of the clay layer and reaches one-hundredth of a unit, at which the strength of the friction does not exceed 50 tons.

To overcome this frictional force, a thrust force of over 50 tons is required, which provides modern mining machines.

If there are pillars of large sections, they are reduced by drilling and blasting to the limiting section.

The direct roofing during the extraction of the pillar develops along the resistant pillars. The size of the collapse in the plan is limited by the line connecting the protruding angles of adjacent pillars. Wherein

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the total volume of the collapsed rocks over the whole extracted does not exceed 60-70 m. Small fall heights and voids volume are necessary and sufficient conditions that prevent workers from

air waves generated by the collapse of the roof.

As a result of using the proposed method, an increase in the completeness of extraction and a decrease in the dilution of the mineral is achieved, which contributes to

improving the rational use of subsoil.

Claims (2)

1. Techniques for the development of solid mineral deposits. Issue 13, Alma-Ata, 1977, p. 70--74. 2. USSR author's certificate for application number 2521065/03, cl. E 21 C 4 G / 06, 1978. - // // V / Vu.