RU2452858C2 - Underground development method of technogenic deep-lying gravel deposits of permafrost zone - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: development is performed during winter period. First, vertical through wells with diameter of 0.5-0.6 m are drilled from surface above developed mine field, through which ice-water mixture is supplied; ratio of solid phase to liquid phase is 1:3 by volume. Filling mass is erected layer by layer; at that, each layer is frozen with forced blowing using cold atmospheric air from blowdown fan. Thickness of a single layer |N_layer| is determined from the following ratio: N_layer=1.5|t_amb.|-20, cm, where: 1.5 and 20 - constant coefficients; |t_amb| - absolute monthly average ambient air temperature of months during winter period, °C.

EFFECT: invention allows reducing the time required for stowing operations and improving the stowing quality.

2 dwg

Description

The invention relates to mining - the development of man-made placer cryolithozones by underground mining, in particular pillars and mining reserves left in alluvial mines (RS) during the initial mining of the deposit.

There is a method of developing technogenic deep-buried alluvial deposits of the North, based on the preliminary simultaneous flooding of previously worked off water in spring with the formation of an ice filling mass after freezing, under the protection of which the previously left pillars and equipment reserves are mined [1] (Prototype).

Despite the cheapness and ease of implementation, the main disadvantages of this method are:

- extremely slow freezing rate of a large volume of water having a positive (4-6 ° C) temperature in the worked-out space of the spent RC, dragging on for several years (from 3 to 8);

- the impossibility of speedy re-mining of industrial sand;

- the water poured into spent RS, being an active thawer, contributes to the thawing of frozen rocks on the sides and the roof of mine workings, pillars, reducing their strength properties;

- blockages of mine workings and failures of the earth's surface during possible deformations of thawed pillars and rocks of the roof of mine workings are not excluded;

- the freezing of previously exhausted RF water that has been poured into the mined space takes place only due to conductive heat exchange with surrounding frozen rocks having a temperature of -5 ÷ -8 ° C, and the possibility of using convective heat exchange with cold atmospheric air is excluded;

- the shift of thawed rocks of the roof of the mine workings and the deformation of the pillars reduces their height, which makes it difficult to conduct mining operations;

- collapsing rocks within the developed space of the CW contribute to the dilution of man-made sand.

An underground method is proposed for the development of technogenic deep-buried alluvial deposits of cryolithozone, including the preliminary erection in winter time in the open mined area of the previously worked off ice of the ice filling array formed by the dosed supply of an ice-water mixture through through bores drilled from the surface, characterized in that the filling array is erected layer by layer, with each layer being frozen by forced blowing with cold atmospheric air pumped by a vent insulator, wherein the ratio of the solid and liquid phases in the filling mixture is 1: 3 by volume, and the unit layer thickness | N _seq. |, determined from the ratio:

N _word = 1.5 | t _N.V. | -20, cm,

where 1,5 and 20 are constant coefficients;

| t _N.V. | - the absolute value of the average monthly outdoor temperature of the winter months.

The implementation of the method will contribute to solving a number of technical and environmental problems:

- a significant reduction in the duration (up to 6-7 months) of filling operations in the spent fuel mix due to the high rate of freezing of stacked layers of the water-ice mixture having a low (near-zero) temperature;

- reduction of dilution of man-made sand;

- high-quality and uniform freezing of the FS space layer-by-layer filled with an ice-water mixture without the formation of talik zones;

- high compression properties of the obtained ice filling mass, excluding the formation of dips on the earth's surface.

In addition, the rapid freezing of a layer of a water-ice filling mixture having a near-zero initial temperature due to intensive blowing with cold atmospheric air prevents thawing of pillars, preserving their compression properties, thereby ensuring the safety of mining operations.

The required technical result in the implementation of the invention is expected to be obtained taking into account the climatic, geocryological features of the region, as well as with the maximum use of natural (natural) resources of the permafrost zone:

- A long winter period with extremely low temperatures;

- the presence of permafrost dispersed rocks with high heat capacity and strength in the frozen state;

- the presence of natural cold, both atmospheric (high potential) and accumulated by rocks.

The essential features introduced into the claims, such as the use of an ice-water mixture and a layered method for laying out the worked out space, make it possible to carry out all work in the winter, thereby eliminating the formation of taliks, providing good compression properties, as well as a high speed of erection of the ice filling mass.

The next significant feature is that ice is used as a solid filler in the filling mixture, which is widespread, easily obtained in winter, and cheap material with high heat capacity, quickly reducing the temperature of the mixture to zero and thereby ensuring high cooling and subsequent freezing speed the backfill layer due to the cold accumulated by the rocks.

Another significant feature is that each erected layer of the backfill array is additionally frozen with atmospheric air (cold) without the use of power plants, significantly accelerating the process of freezing while saving material costs.

The inventive method is illustrated by two drawings (Figure 1 and Figure 2). Figure 1 presents the plan of the spent RS, a technological complex with the arrangement of all equipment, reflecting all the stages of work on the development of technogenic reserves in the practical implementation of the method, and Figure 2 is a transverse section.

Symbols adopted in the drawings:

1 - the surface of the earth;

2 - the worked-out space of the spent RS;

3 - the upper boundary of the technogenic layer of sand;

4 - through vertical wells intended for supplying filling mixture (water with crushed ice);

5 - ventilation wells;

6 - reservoir;

7 - water pump;

8 - water pipeline;

9 - crushed ice;

10 - erected filling (water-ice) layer;

11 - discharge fan;

12 - ventilation sleeve;

13 - tape pillars;

14 - instrument stocks of industrial sand.

The implementation of the proposed method in practice is as follows. Initially, during the winter period, from the earth's surface 1, within the worked-out area of the previously worked-out RS 2, they are drilled to the upper boundary of the technogenic sand layer 3 of a series of through vertical wells 4 (with a diameter of 500-600 mm) intended for supplying an ice-water filling mixture. In addition, two ventilation wells 5 of the same diameter are drilled at the boundaries of the spent mine field. In stowing the well when reaching a stable negative average daily atmospheric temperature (t _{cp. D.} ≈-10 ° C) from the reservoir 6 pump 7 through line 8 is supplied with water mixed with crushed ice 9 to form a water-ice mixture (ratio of solid and liquid phases mixture 1: 3 by volume), which fills the entire worked-out space of the spent oil and gas layer with a thickness of 0.3 ÷ 0.5 m to form a filling array 10. Then, the filling wells are temporarily closed and the exhausted space is purged with cold th atmospheric air blowing fan 11 to the vent hose 12 to complete freezing erected layer of water-ice Bookmarks (t≈-10 ° C).

After that, with the above operations, the second layer of the water-ice filling mixture is laid out with its subsequent freezing and so on until the complete laying of the entire worked out space of the RS.

In summertime, the ice rush laid by ice is preserved, and in the next winter period, opening and ventilation openings, and then preparatory and rifted openings (on ice) are restored (or re-run) using traditional technology. After that, they begin to work out the tape pillars 13 and the instrument stocks of technogenic sands 14. The formed worked-out space can also be laid with an ice bookmark using the technology described above. It is not ruled out that sand enrichment tailings can be used as filling material, as well as flooding of the spent mine by spring water in the spring.

The main advantages of the proposed method:

- safety of work;

- the cheapness of the filling material;

- low complexity of the construction of filling arrays;

- high mechanization and low cost of drilling;

- low material costs for the purchase of equipment and the implementation of all types of work;

- a small number of technological operations;

- low costs of freezing filling arrays through the use of high-potential natural (atmospheric) cold;

- high speed freezing layer by layer erected stowing arrays;

- high compression properties of the erected filling arrays, ensuring the safety of work and the integrity of the earth's surface;

- stabilization of the temperature regime and ensuring the continuity of the technologically disturbed mountain range.

Information sources

1. Badmaev RS, Gorlov Yu.A., Dushkin AI, The technology of underground mining of placers with minimal losses in the bowels, Kolyma, 1980, No. 2, p. 4-7.

Claims (1)

An underground method for developing technogenic deep-buried alluvial deposits of cryolithozone, including the preliminary erection in winter time of the previously worked out alluvial mine of an ice filling array formed in the open mined space by dosed supply of an ice-ice mixture through through holes drilled from the surface, characterized in that the filling array is erected in layers, wherein each layer is frozen by forced blowing with cold atmospheric air pumped by a valve torus, and the ratio of solid and liquid phases in the filling mixture is 1: 3 by volume, and the thickness of a single layer | N _sl | determined from the ratio:
N _SL = 1.5 | t _HB | -20, cm,
where 1,5 and 20 are constant coefficients;
| t _{H. B.} | - the absolute value of the monthly average outdoor temperature of the winter months, ° C.

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