CS242338B1 - The way to reduce the load on large-area contact pillars in the surrounding massif area - Google Patents

Abstract

A method of reducing the load on large-area contact pillars in the vicinity of the excavated area, for example when extracting a magnesite deposit, which will allow for a reduction in the thickness of the pillar and an increase in the extraction rate. From the large-area pillar (1), from the excavated area (2) to the contact (4) with the weak rock (5), one hole (3) is cut out at a distance of two chambers for the spontaneous release of a part (6) of this rock (5). A retaining platform (7) is left under the system of holes (3) when the ceiling pillar is disconnected to retain the weak rock (5).

Description

The invention relates to a method of reducing the load on large-area contact pillars in the vicinity of extracted areas in a mountain massif.

In the case of underground mining of useful minerals, it is often necessary to leave a layer of intact mountain mass, forming a protective pillar, in the vicinity of the mined area in order to ensure occupational and technological safety. In the event that the pllier separates the mining area from a low solid rock, e.g. slate, it is a contact pillar, which prevents the penetration of low solid rock into the mining area, thus preventing unwanted contamination of the utility pipe. The low solid rock gradually increases the excavation by its weight on the pillar surface. In the process of mining in depth, e.g. when two or more mining horizons are obtained, the contact pillar is referred to as a large-area. By increasing the area of the pillar, its load is also increased, and consequently its mass, which represents the loss of the utility wastes, increases in order to maintain the necessary stability. The pillar thickness must be determined in relation to its maximum required stable flat.

The technical problem solved by the invention is to reduce the load on the large-area contact pillar and thereby reduce its depth. This objective makes it possible to achieve a method of reducing the load on large-area contact pillars in the underground mining of useful minerals. According to the invention, it is based on the fact that in the large-area contact pillar, one opening for the spontaneous release of a part of this rock is always cut from the space to be contacted with a low-strength rock over a distance of two chambers. Under the set of openings, when the ceiling pillar is disconnected, the retaining platform is left to retain the little solid rock.

An advantage of such a method according to the invention is that its load is reduced and its required stability is maintained and its mass is reduced, which represents the loss of useful wastes. Also contamination of the utility timber is avoided.

In the attached drawing, a large axial sectional view of a large-area contact pillar with a hole arrangement according to the invention is spatially shown.

In the large-area contact pillar 1 above the excavated spaces 2 of the two horizons, a set of openings 3 is cut except for contact 4 with a low solid rock 5. Part B of the self-loosened low-strength rock 5 is trapped on the platform 7 resulting from incomplete disposal of the ceiling pillar of the chamber system.

The horizontal distance of the holes 3 corresponds to the distance of the two chambers. In this case, the area of the openings 3 was 10 X 10 meters. The dimensions relate to the overlying large-area pillar above the mining area of the large-depth magnesite deposit. The overburden is made of ylites. Applying the method of reducing the load of the large-area contact pillar of the present invention will allow a reduction of losses of 25-30%.

Claims (2)

SUBJECT 1. A method of reducing the load of large-area contact plliers in the vicinity of a well-occupied area in a massive mountain beyond which there is low solid rock, characterized in that in the large-area contact pillar (1j) (5) produce a hole (3J) for the distance of two chambers, in order to spontaneously release part (6) of this rock (5). Method according to claim 1, characterized in that a retaining platform (7J) is retained under the set of openings (3J) for detaching the ceiling pillar (5) for detaching the ceiling pillar.