RU2365753C1 - Method of minerals excavation from pillars - Google Patents

Abstract

FIELD: mining engineering.

SUBSTANCE: invention elates to mining engineering and can be used at excavation by open-cut method of minerals from pillars, leaved at introduction of underground winning. Method includes opening of pillars, excavation of mineral from it and formation of support prism of pit wall from overburdens. Additionally overburdens are leaved on overlying benches of open pit of volume, enough for formation of support prism with parametres, providing specified stability of pit wall, and at a distance from support prism, providing implementation of its movement with minimum-cost. Excavation of minerals from pillars and formation of support prism from overburdens it implemented simultaneously. Outcrop length of prism of possible failure equal to distance between front edge of winning works and boundary of support prism, which is selected from condition providing permissible minimum stability factor of pit wall.

EFFECT: effectiveness increase of open cast minings for extraction of minerals from pillars in peripheral area of open pit.

1 ex, 3 dwg

Description

The invention relates to mining, and more particularly to the technology of combined mining of ore reserves, and can be used for open pit mining of minerals from pillars left during underground mining.

There is a method of mining pillars, including the sinking of preparatory and grooved workings in the soil of the panel, laying of the worked out space with filling material, drilling holes in pillars with the subsequent placement of explosive charges in them and blasting them, releasing ore into the preparatory workings / 1 /.

The disadvantage of this method is the low efficiency of mining, which is associated with increased costs for the production of additional preparatory workings and the full laying of the worked out space, on the one hand, and on the other hand, low volumes of ore mined.

The closest to this invention in terms of technical nature and the achieved result is a method of extracting minerals, including opening the pillars of minerals with subsequent placement of overburden rocks in the prism of the stop, setting the sides of the quarry on the ultimate contour, extracting ore reserves from pillars in separate blocks and subsequent loading of the side into within the spent blocks overburden / 2 /.

The disadvantage of this method is the decrease in the efficiency of mining due to an increase in the production cycle due to the development of pillars in separate blocks.

In addition, for the subsequent loading of the quarry side in the area of the spent block, it is necessary to temporarily store overburden, which requires additional costs for the organization of a transshipment point. The temporary gap between the excavation of the pillars and the compensation for the weakening of the side due to its loading by overburden will not allow to increase the width of the excavator's working platform (length of the block) with the weakened section of the side set to the maximum contour with the maximum possible angle of inclination. This will lead to the need for additional stripping operations to flatten the side or to narrow the excavator work site, which will sharply reduce the efficiency of loading and hauling processes.

The objective of the present invention is to increase the efficiency of open cast mining to recover minerals from pillars in the contour zone of the quarry by reducing the cost of moving overburden into the prism of emphasis and increasing the productivity of mineral extraction.

This is achieved by the fact that in the method of extracting minerals from pillars, including opening pillars, extracting minerals from them and forming a prism of an abutment of the quarry side from overburden, overburden rocks leave on the overlying ledges of the quarry a volume sufficient to form a prism of abutment with parameters providing the specified stability of the pit side, and at a distance from the stop prism, which allows them to be moved at minimal cost, and mineral extraction from pillars and the formation of Isms of emphasis from overburden are carried out simultaneously, while the length of exposure of the prism of possible collapse is equal to the distance between the front of the mining operations and the boundary of the persistent prism, which is chosen from the condition that provides the minimum allowable margin of stability of the pit side.

The simultaneous extraction of mineral from pillars and the formation of a prism of emphasis allows to increase the productivity of mineral extraction by combining in time the processes of dumping a persistent prism, extracting mineral from pillars and supplying the pit side to the ultimate contour. In addition, the standing time of the side of the bead located above the mining area is reduced, which allows you to achieve the most steep slope angle of the bead when it is set to the maximum contour while maintaining the necessary width of the working platform.

Figure 1 shows the technological diagram of the extraction of minerals from pillars in the contour zone of the quarry, figure 2 - section aa, figure 3 is a graph of the dependence of the margin of safety margin η from the exposure length of the prism of the possible collapse L.

The method of extraction of minerals from pillars is as follows. First, the volume of overburden rocks necessary for the formation of a prism of an abutment 1 is determined with the parameters ensuring a given stability of the side of the quarry in the limiting position 2. This volume of overburden rocks is left on one or several overlying ledges 3, not bringing them to the limiting contour 2, with the possibility of their further movement with minimal cost in the prism of the stop 1. Then carry out the repayment of the underground voids 4 and the extraction of minerals from pillars 5 according to known technology, for example, using I eat blasting. Then carry out the formation of the prism of the stop 1 by moving the overburden by means of, for example, a wheel loader 6 from one or more overlying ledges 3. Extraction of minerals from the pillars and the formation of the prism of the stop is carried out simultaneously. In this case, the exposure length of the prism of possible collapse L, equal to the distance between the front of the mining operations and the boundary of the thrust prism, is selected from the condition that provides the minimum allowable margin of stability of the side of the quarry.

An example of the implementation of the method of mining minerals from pillars

The described method is carried out for the conditions of one of the deposits of non-ferrous metals located in Central Kazakhstan and practiced by a combined method.

When mining the quarry expansion section, flanking to the limit circuit 2 is carried out under conditions of undermining of the rock mass with undeveloped one- and two-tier underground voids 4 located within the horizons of 280-320 m. According to the calculations of the side stability in these conditions at a side height of 140-160 m the maximum allowable tilt angles vary between 32-37 °.

Before the board approaches the design contour, work is carried out according to generally accepted technology: within the horizons of 280-320 m - two 20-meter ledges, and horizons of 320-440 m - 15-meter ledges. The five upper ledges (mountains 365–440 m) are led to limit circuit 2, and the four upper ledges are doubled, forming two 30-meter ledges with a slope angle of 55 ° and the width of the safety berms on the mountains. 380 and 410 m, equal to 10-11 m. Two 15-meter ledges (mountains 335 and 350 m) do not reach the limit contour and leave a certain amount of overburden on them, sufficient to fill the prism of abutment 1. Overburden from the mountains. 350 m cross over to the mountains. 335 m and then transported to the place of formation of the prism stop 1.

Mining operations are carried out according to well-known technology, including the redemption of underground voids 4 and ceilings from the mountains. 320 m, the safe and permissible power of which is determined on the basis of the experience of redeeming ceilings in the quarries of Kazkhmys Corporation, removing overburden that collapsed into the depleted space after redemption, and excavating ore reserves from abandoned interchamber pillars 5.

The prism of the stop is poured with a width along the bottom of the quarry equal to 50 m, 55 m high, and a slope angle of 36 ° from the mountains. 335 m following the advance of the mining front. Advance of mining operations of the dumped prism of an emphasis on mountains. 320 m should be no more than 55 m. The length of the prism of possible collapse, equal to 55 m, provides a safety factor of at least η = 1.05. What is possible if the side staying at the limit of stability of no more than two months and the formation of two wide berms of horizons of 350 and 335 m. Figure 3 shows the calculated dependence of the change in the safety factor of the side of the quarry η on the exposure length of the prism of possible collapse L.

When conducting overburden work in the mountains. 335 and 350 m and dumping the prism of the stop 1, it is advisable to use powerful pneumatic wheel loaders 6.

Thus, this method allows to increase the efficiency of mining operations by reducing the cost of additional volumes of overburden, reducing the distance of transportation of overburden and increasing the productivity of handling equipment in mining.

Information sources

1. USSR author's certificate No. 1266989, according to class. Е21С 41/22 from 06/28/85.

2. USSR author's certificate No. 636391, class. Е21С 41/28 from 01.06.77 (prototype).

Claims (1)

A method of extracting minerals from pillars, including opening pillars, extracting minerals from them and forming a prism of abutment of the quarry side from overburden, characterized in that the overburden leaves on overlying steps of the quarry with a volume sufficient to form a prism of abutment with parameters that provide a given stability side of the quarry, and at a distance from the stop prism, allowing them to be moved at minimal cost, and the extraction of minerals from the pillars and the formation of a prism from time to overburden carried out simultaneously with the length of exposure of a possible collapse of the prism is equal to the distance between the front and the edge extraction operations abutment prism, which is selected from the condition providing the minimum acceptable stability margin career bead.

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