SU1671861A1 - Method of borehole production of minerals from thick formations - Google Patents

Abstract

The invention relates to geotechnology and m. used in downhole hydroproduction minerals. The goal is to increase the efficiency of work on the extraction of materials from underground formations by simplifying the process of softening of the materials of the formation and expanding the conditions for applying the method. To do this, the subterranean formation is opened by the borehole 1, in which the downhole jetting unit (GMA) 2 is placed. With the latter, a interval erosion is effected along the height of the chambers (K) 4, 5, leaving the pillars 3 between them. Interval erosion of the rocks is carried out with the formation of inclined roofs from the well 1 and soil filled with K 4, 5. GMA 2 is then removed and K is filled with materials expanding during hardening, for example, with a solution of expanding cement. The even K 5 is left blank. To ensure this, before filling the odd K 4, the adjoining portion of the well 1 is filled by an amount excluding the penetration of the expanding material into the downstream K. The upper part K is filled with an expanding material, the setting intensity of which is higher than the intensity of setting of the material in the lower part. Due to the increase in the aggregate volume in K 4, in the presence of voids in K 5, when the aggregate material hardens, there is a sharp redistribution of load on the pillars 3 and softening of the rocks. Then, by drilling the plugs, the well is restored, the GMA is placed in it, and the weakening of the rocks of the pillars 3 are eroded. f-ly, 2 ill.

Description

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The invention relates to geotechnology and can be used in downhole hydraulic mining of minerals in a wide range of mining and geological conditions, with increased strength of rocks composing an underground formation.

The purpose of the invention is to increase the efficiency of work on the extraction of materials from subterranean formations by simplifying the process of weakening the materials of the formation and expanding the conditions for applying the method.

Fig. 1 shows a scheme for filling the intervals with an expanding material; figure 2 - erosion diagram of softened rocks

The method is carried out as follows.

The initial formation to the lower boundary of the extraction is opened by the borehole 1, in which the downhole jetting unit 2 is placed. With this unit, a circular interval of the formation height is eroded, leaving the pillars 3 between the chambers. The odd chambers 4 (counting from the roof of the formation) are conducted with a radius greater than the radius of the extraction chamber, and the even chambers 5 are blurred with the radius of the extraction chamber.

It is preferable to wash the rocks from the upper limit to the lower. The height of said chambers 4 and 5 is substantially less than the power of the remaining pillars 3 between the chambers.

After the chambers 4 and 5 are formed, the well hydraulic unit 2 is extracted from the well and in sequence from the lower boundary to the upper one. The chambers, after one, are filled with materials expanding during hardening, for example with a solution of expanding cement, and the even chambers 5 are left unfilled. To ensure this, before filling the chamber 4, the adjoining portion of the well 1 is filled by an amount precluding the penetration of the expanding material into the downstream chamber.

The material that expands during hardening is supplied by means of hoses that are lowered into the well to the level of the corresponding interval, while filling the chamber volume is filled after filling the well section below it. The upper part of the chamber is filled with expansion material, the setting intensity of which is higher than the intensity of material setting in bottom of the chamber (depending on the specific conditions

it is possible either to add hardening accelerators to the filling material, or to apply a special quick-hardening material of a different composition, for example, based on synthetic resins or based on fast-setting cement),

The filling rate of the chambers and, accordingly, the parameters of the equipment used (capacity) are determined by the parameters of the material used for the filling (the filling time of the interval should be less than the time from the preparation of this material to the beginning of its hardening-expansion, i.e.

5 triggers).

A prerequisite for the implementation of the method is that the roof and the soil of the chamber are inclined from the well, since this ensures

0 complete filling of the chamber with expanding material and efficient use of expansion of the hardening material. In this case, the slope of the roof should be significantly more gentle than the soil

5 (practically the angle of inclination of the roof should be no more than 5 ° to the horizontal), otherwise the conditions for destruction of the pillar, located above the chamber 4, deteriorate. With high permeability of rocks,

Before forming the chambers, it is necessary, before filling the chambers with expanding hardening materials, to apply a coating on the walls, for example, spatter-concrete, in order to exclude some

5 of the formation mass adjacent to the interval during the hardening process of the expanding hardening material.

After completion of the work on filling chambers 4 with expanding materials,

0 preserve the zone of operation until the end of hardening of the expanding material, which can be judged by test drilling into the uppermost chamber 4, as well as on the basis of preliminary experimental works. Due to the increase in the filling volume in chambers 4 in the presence of voids in chambers 5 (working, in fact, as an outcrop surface for an array of rocks, the pillars are 3) when

0 hardening of the filler material, there is a sharp redistribution of load on the pillars 3 and softening of the rocks

In each particular case, on the basis of experiments, the distribution of the height of even and even chambers is also pillars to ensure the most even and effective softening of the height of chambers 4 and 5, the rocks of which need to be washed out in the undeadrated state of the jetting unit 2

Next, the well 1 is restored by drilling in it the plugs formed at the levels of the chambers 4. A downhole jetting unit is placed in the restored well and the erosion of softened rocks of the pillars 3 is performed.

Claims (2)

Claim 1. Borehole extraction of materials from thick underground formations, including opening the formation with a well, interval-by-height scouring of rocks, leaving the pillars between the chambers, filling the chambers through one expanding material, preserving the well until the end of the process of expanding the material with softening the pillars, eroding of softened rocks and the rise of rock mass to the surface, which is characterized by the fact that, in order to increase the efficiency of extraction and expansion of the conditions of application of the method, interval erosion of the rocks is carried out with the formation of sloping from the well of the roof and soil of the filled chambers; before filling the chambers, the adjoining portion of the well is filled to the extent that the 0 expandable material into the downstream chamber, and hardening expandable mixtures, such as expandable cements, are used as the expanding material. five 2. A method according to claim 1, characterized in that the upper part of the chambers is filled with an expanding material, the seizure intensity of which is higher than the seizure intensity of the material in the lower part of the chamber.