SU1633125A1 - Method of protecting underground workings from water ingress - Google Patents

Abstract

The invention relates to mining protém and is intended to develop the deep part of a kimberlite pipe located under the bottom of a spent quarry in the Far North regions. The goal is to ensure reliable isolation of underground work in the permafrost of the Far North from the penetration of water from aquifers disturbed by mining operations on the surface. Between the underground mining and the reservoir on the surface create a safety pillar. Moreover, the bed of the reservoir on the surface is created by excavation of rocks, and the bottom is formed in the zone of permafrost. On the DN side, a coating of a freeze-consolidated clay mixture is applied to the bottom of the reservoir. As the latter, wash tailings of the processing plant are used with a density higher than the density of groundwater. Then the reservoir is filled with water from the aquifers located above the created coating. 1 hp f-ly, 3 ill. Yo

Description

The invention relates to the mining industry and can be used to develop the deep part of a kimberlite pipe located under the bottom of a spent quarry in the regions of the Far North.

The purpose of the invention is to provide reliable isolation of underground works in the permafrost rocks of the Far North from the penetration of water from water-saturated formations disturbed by mining operations on the surface.

Figure 1 shows a schematic diagram of the quarry, a cross section; 2 and 3 are examples of the method.

The method is carried out as follows.

After completion of mining operations on the surface in the quarry 1 of the kimberlite pipe 2, they start, by supplying the clay pulp of the washing tails of the processing plant through pipeline 3, to form an artificial permafrost stratum overlap 4 at the bottom of the quarry 5 on the safety pillar 6 between the underground and open pit mining located in permafrost zone 7. At the same time, in order to reduce the amount of unfrozen water remaining in the frozen array, the freezing of the thickness is carried out in layers, for example, 5 cm and air temperature not higher than minus 20-30 ° C. Before the spring flood, artificial multi-year frozen cover is covered with a frost-proof overburden layer, the weight of which corresponds to the backing

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to the living force of an artificial overlap on the surface of the water, and then the quarry is flooded with water 8 coming from above.

The artificial overlap created by the proposed method is ensured by stationary conditions of the permafrost stratum due to the fact that the depth of seasonal thawing and freezing reaching 3-10 m extends only to the protective layer of rocks and the protective water column conditions similar to the natural conditions of a long-term physico-chemical process of formation of a stable texture and structure of permafrost soil, which provides the property of reliable waterproof At the same time, the sealing of the safety overlap contact with the pit walls is done by limiting the areal distribution of the volume expansion of the water-ice phase transformation of the liquid mass. In accordance with the cryogenic structure of frozen soils, depending on many factors, including the orientation of primary water crystals, the growth of ice-cement crystals occurs mainly on the surface of debris (cores, in this case dispersed clay particles). in a closed volume, it is accompanied by the expansion of the mineral skeleton by the value of the volume expansion of water during the phase transition.

Having ensured the isolation of water inflow, the ore body is completely developed under the pit bottom by an underground method, for example, production horizons 10 upwards with laying the worked-out space with hardening material 11.

In the presence of reservoir water 12 (Fig. 2) in the permafrost (including pressure and brine), the pit below the stratum is preliminarily under protection of overlying open-pit water-reducing wells 13 by an amount sufficient to accommodate

artificial overlap, after the construction of which the produced water is released into the quarry space above the created overlap. Pressurized water, filled career space, rises to level 14 according to the size of the head.

Under conditions where it is impossible to deepen a pit below an aquifer using water-deadening wells, we first construct a vertical pressure curtain 15 (Fig. 3) by a known method around the ore body with a height corresponding to the pressure of the water in the reservoir. Then, upon reaching the bottom of the quarry with the required depth mark, the proposed artificial overlap of the proposed method is constructed and the produced water is released into the upper part of the quarry space, stopping the expensive

operation of water downhole wells.

Claims (2)

1. The method of protecting underground works from water penetration, including the creation safety pillar between the underground mining and the reservoir on the surface, the coating from the side of the surface to the bottom of the reservoir in a trenchant with a waterproof coating, different in order to ensure reliable isolation of underground works in the permafrost of the Far North from the penetration of water from aquifers, disturbed by mining works on the day surface, the reservoir bed on the day surface is created by excavation of rocks, while the bottom is formed in the zone of permafrost rocks, and the coating is made of cemented by freezing the clay mixture, then the reservoir is filled with water from the aquifers located above the created coating. 2. A method according to claim 1, characterized in that the quality of the clay mixture is the flushing tailings of the processing plant with a density higher than the density of groundwater. "44 15 12 /  . . ; about 7  I f - r t f -J-r --l3-4 g g Fm.z