RU2451179C1 - Method of pits conservation with flooding of selected area - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method of pits conservation, including open-pit field mining, foundation pit with flattening of pit edges and their reinforcement along the periphery and pit flooding with water. Note that edges flattening is done till reaching the angle of safe cut. Along the lower flooded area of the edges along the whole periphery together with flattening of edges from sheared massive there formed is a retaining embankment till the mark corresponding the minimum water level in pit. After that the retaining embankment is covered by protective layer from macrofragmental material till the mark exceeding the maximum water level in pit to the height of wave run-up. Dumping of protective layer from macrofragmental material is done by segregation of consertal rocks as a result of mining-and-transport equipment unloading at the upper edge of the pit, the edges flattening till reaching the angle of natural slope is done above the minimum water level in pit.

EFFECT: increase of pit edges stability in the area of abrasion.

3 cl, 1 dwg

Description

The invention relates to mining and can be used for the conservation of quarries, the bottom of which is located mainly below the natural level of groundwater.

In connection with the country's transition to a market economy with the restructuring of many mining enterprises in recent years, mining at a number of sites has become unprofitable and many quarries and sites have been conserved. At the same time, if as a result of flooding of such quarries it is possible to ensure the preservation of mineral resources, then environmental safety is often not achieved. As a result of the impact of waves, significant coastal abrasion is noted with their landslide and shedding.

Known methods of forming slopes with a high above-water part of the sides of worked open pits, with flattening, creation of anti-erosion berms and the beach area (Tomakov P.I. et al. Ecology and environmental protection during open pit mining. - M.: Publishing House of ISTU, 1994. - S. 189-190).

This method is intended for the creation and rational use of reservoirs in spent quarries (including in the recreational direction) and is not economically feasible with a temporary suspension of mining.

There is a known method of reclamation in open pit mining, including mining a quarry field and then flattening the surface of the sides (patent 1062392, class E21C 41/00). With this method, the flattening of the sides is carried out to slope angles, providing the possibility of applying a soil layer to them. In the conditions of temporary conservation with the continuation of the subsequent development of the field, flattening the sides to angles ensuring the restoration of the biological productivity of the land is impractical because of the significant costs both in the process of conservation and during the re-conservation of reserves.

A known method of restoring disturbed lands during open pit mining (RF patent 2109427, class A01B 79/02), including mining a quarry field and leveling it with overburden. The method is aimed at restoring the fertility of disturbed lands and is associated with significant labor costs, which are not justified in the event of the subsequent re-conservation of this facility.

A device for strengthening the subgrade or slopes (patent 2032022 RF, according to CL E02D 17/20, E02B 3/12), which includes connected to each other square frames filled with filler, and anchors. The device provides erosion resistance of the slopes, however, it is associated with the high complexity of installation and dismantling during conservation of the object.

A known method of protecting soils from erosion (RF patent 2267514, class C09K 17/40), based on the strengthening of slopes by applying moisture absorbents to the soil and applying an aqueous solution of polyvinyl alcohol to the surface. This method can be used on fairly gentle slopes with permeable loose rocks. For conditions of conservation of quarries with fairly steep sides, the described method is not acceptable.

All of the above methods are quite laborious and expensive and cannot be recommended for a short stop of work. When mines are mothballed, the prevention of abrasion should be carried out in a manner that ensures the minimum amount of work with sufficient strengthening of the quarry sides and the possibility of quick mothballing of the facility.

The closest in technical essence and the achieved result is a method of reclamation of disturbed lands (patent 2325534, class E21C 41/32, Boldyrev S.V., Lubochkin I.P., Mukhortov V.V. et al. May 27, 2008), which includes separate excavation, movement and storage of soil layer and overburden in separate tape dumps, mining of a quarry field, excavation of a pit with flattening of the quarry sides to a steepness of slopes of no more than 25 degrees, with subsequent planning and strengthening of the quarry sides around its entire perimeter by means of properties of combined rammed piles in rolled wells and pouring a buffer layer of sand with subsequent laying of a curb of stones on it with cement mortar, then on graded slopes they make sand and gravel, and a clay layer at least 20 cm thick is applied to the walls and bottom of the foundation pit and compacted followed by moisturizing with water. After the clay layer has completely dried, all cracks are wiped with thick clay. Then in the same way two more layers of clay are successively laid, the last third layer of clay is rubbed and a thin layer of gravel with coarse sand is rammed into the still wet surface. After that, the bottom of the pit is sprinkled with a layer of gravel with a grain size of 3-5 cm or pre-crushed 3-5 cm construction waste in the form of broken burnt brick, concrete, reinforced concrete, ceramic tile, and the pit is filled with water, while the depth of the pit should not be less 5 meters.

Common signs of the prototype and the proposed method are: mining the quarry field, the device pit with flattening the sides of the quarry and strengthening them around the perimeter, the subsequent flooding of the pit with water.

A comparative analysis of the proposed technical solution with the prototype shows that the main disadvantage of the latter is the large amount of quite complex work, including to flatten the quarry sides to an angle of 25 ° and to strengthen them with the help of rammed piles, sanding a buffer layer, laying a stone curb on a cement mortar, applying several layers of clay with subsequent grouting, tamping a layer of gravel with coarse sand and backfilling with a layer of gravel and waste building materials. A significant amount of work is required during the re-commissioning of the facility.

The invention is directed to the creation of a technology for the conservation of quarries, which provides the minimum amount of work with sufficient strengthening of the sides of the quarry and the possibility of rapid decommissioning of the facility.

The technical result consists in strengthening the sides of the quarry in the zone of abrasion (wave impact) with existing coarse material, which is poured onto a flooded retaining embankment formed in the process of flattening the sides, as well as providing the possibility of quick re-conservation of the object.

The technical result is achieved by the fact that in the method of conservation of quarries with flooding of the mined space described in claim 1, which includes mining a quarry field, a pit device with flattening the sides of the quarry and strengthening them along the entire perimeter, subsequent flooding of the pit with water, according to the invention, flattening the sides carried out until the angle of steady slope is reached, while along the lower flooded part of the sides along the entire perimeter simultaneously with the flattening of the sides from the slice of the formed rocks form a retaining embankment to a mark corresponding to the minimum water level in the pit, after which a protective layer of coarse material is poured onto the retaining embankment to a mark exceeding the maximum water level in the foundation pit by the wave driving height.

Long-term observations of flooded mine workings showed that the most intense erosion of the quarry sides occurs due to abrasion. At the same time, in the wave impact zone, the board is washed with the formation of a recess, which serves as the reason for the subsequent shedding and sliding of the mass of overlying rocks. Strengthening the washout zone with a protective layer of coarse material can prevent abrasion and ensure the necessary stability of the sides. The protective layer is sprinkled on the entire part of the side, subject to wave erosion: from the water edge in the pit during the low-water period to the mark corresponding to the height of the wave driving in at the maximum water level. The wave driving height is determined by known dependencies. To form a protective layer of coarse material, a retaining embankment is created. The embankment is created from rocks taken from the top of the side during its flattening to an angle of steady slope. The supporting embankment is poured to the mark corresponding to the minimum predicted water level in the pit. The maximum and minimum water levels in the pit are established by the results of hydrogeological surveys with the determination of the limits of groundwater level fluctuations, as well as by the results of calculations of the water balance of the created reservoir in low-water and flood periods.

The technical result is achieved by the fact that in the method of conservation of quarries, described in paragraphs 1 and 2 of the claims, including flattening the sides until a steady slope is reached, forming simultaneously with flattening along the lower flooded part of the sides along the entire perimeter of the retaining embankment from the cut rocks to the mark, corresponding to the minimum water level in the pit, and pouring on the retaining embankment of the protective layer of coarse material to a mark exceeding the maximum water level in the pit and racking-wave height, according to the invention the protective layer of the dumping of coarse material is accomplished by segregation inequigranular rocks as a result of mining equipment unloading at the upper edge of the pit boards.

The backing of the protective layer can be carried out due to the natural segregation of different-grained rocks during their rolling along the side of the quarry, which is laid out to the angle of natural slope. Due to the large radius, large pieces of rock roll faster and further, so a protective layer is formed from them. Draglines are most often used to flatten the sides. In this case, after creating the retaining embankment, the excavator bucket is unloaded at the upper edge of the side during the rotation of the boom. In this process, the segregation of rocks is enhanced by centrifugal inertia.

The technical result is achieved by the fact that in the method of reclamation of quarries, characterized in claims 1 and 3 of the claims, including flattening the sides until a steady slope is reached, forming simultaneously with flattening along the lower flooded part of the sides along the entire perimeter of the retaining embankment from the cut rocks to the mark, corresponding to the minimum water level in the pit, and pouring on the retaining embankment of the protective layer of coarse material to a mark exceeding the maximum water level in the pit e to the wave driving height, according to the invention, the flattening of the sides until the angle of repose is reached is carried out only above the minimum water level in the pit.

After flooding the pit, the water will support the side, therefore, the angle of its steady slope increases (the angle of natural slope of loose deposits in water is greater than in the atmosphere). Therefore, it is advisable to flatten the board only above the minimum water level in the pit.

Differences from the prototype prove the "novelty" of the proposed method.

It is known to flatten the sides until a stable slope is reached during dry conservation of the workings [Chemezov VV, Kovryzhnikov VL Land use and reclamation of disturbed lands in the development of gold and diamond deposits. - Irkutsk: Publishing House of OJSC Irgiredmet, 2007. - P.104-105], which allows in the absence of flooding to ensure sufficient stability of the sides and slopes. However, when creating in a pond due to abrasion of the sides as a result of wave action with the formation of a recess (deepening) along the coastline, their stability is ensured for a short time and the process of collapse, shedding of rocks located above the water level in the pit begins. Therefore, the resistance of the sides to erosion is not provided.

Known technologies for the creation of retaining embankments, as well as the loading of slopes with coarse soil to ensure the necessary stability of the sides and slopes of dumps [Vakhromeev II and others. Hydrotechnics in the peat and mining industry. - M .: Nedra, 1984, S.109-111, RF patent 1040152, E21C 41/00].

However, in known technical solutions, the retaining embankment only supports the side from collapse and shedding. In the proposed technical solution, it is the basis (basis) for creating a protective layer of coarse material.

Known methods for protecting the sides from abrasion using coarse material [Vakhromeev II and others. Hydrotechnics in the peat and mining industry. - M .: Nedra, 1984, S.220-222]. However, in the well-known technical solutions, coarse-grained material is sprinkled on a fairly flat surface, or special measures are used to fix it (including metal grids, gratings). In the proposed technical solution, it is held in the abrasion zone due to the retaining embankment. In this case, the formation of a protective layer is ensured during the rolling of coarse material along the side of the quarry, which greatly simplifies the technology and reduces the cost of creating this layer.

The unknown influence of features similar to the distinctive essential features of the proposed method on the technical result achieved by the claimed technical solution proves its compliance with the patentability condition "inventive step".

The invention is illustrated in the drawing, where figure 1 shows the scheme of conservation with flooding of the developed space:

1 - the initial side of the quarry before the start of conservation;

2 - rocks cut from the top of the side during its flattening;

3 - board quarry after flattening;

4 - retaining embankment;

5 - the bottom of the quarry;

6 - a protective layer of coarse material.

The inventive method of conservation is as follows. After partial mining of the quarry field, flattening of the sides 1 is carried out mainly using dragline excavators. In this case, the rocks cut from the upper part of the board - 2, are laid in the retaining mound 4 at its lower part adjacent to the bottom of the quarry 5. In the process of flattening, the side of the quarry 3 is formed with the angle of repose of rocks γ. The retaining embankment 4 is formed to the mark corresponding to the minimum water level in the pit (UNV). The volume and width of the embankment is determined based on the volume of the rock cut from the upper part of the side 2. The supporting embankment is sprinkled with the angle of repose of loosened rocks β. After creating a retaining wall on it using mining and transport equipment (draglines, excavators such as a mechanical shovel, loaders, bulldozers, vehicles), a protective layer is poured from coarse material - 6 to a mark corresponding to the height of the wave driving in at the maximum water level in the pit (air-blast) . The protective layer allows you to prevent abrasion in the wave impact zone and erosion above the located side of the quarry - 3.

The conservation method described in paragraph 2 of the claims is carried out as follows. To create a protective layer, a different-grained rock is delivered to the quarry board, which, when unloading vehicles, reloading by an excavator, and bulldozer feed, is poured onto the laid side of the quarry 3 and, in the process of rolling and segregation, a protective layer is formed 6. Inertia is given to the rock to segregate during unloading, including due to centrifugal forces arising from the movement of the excavator bucket.

The conservation method described in paragraph 3 of the claims is as follows. The flattening of the bead 1 is carried out mainly by a dragline or a backhoe shovel to an angle γ to the mark corresponding to the minimum water level in the pit (UNV). Below the water level due to the retaining embankment 4 and the water masses in the pit, the side is sufficiently stable against destruction formed prior to conservation with an angle α.

Claims (3)

1. A method of preserving quarries with flooding of the mined-out space, including mining the quarry field, arranging a pit with flattening the sides of the quarry and strengthening them along the entire perimeter, subsequent flooding of the pit with water, characterized in that the flattening of the sides is carried out until the angle of slope is reached, along the lower the flooded part of the sides along the entire perimeter simultaneously with the flattening of the sides of the cut rocks form a retaining embankment to the level corresponding to the minimum level in rows in the trench, after which the retaining mound backfilled protective layer of coarse material to the level higher than the maximum water level in the trench to a height racking wave. 2. The method according to claim 1, characterized in that the backfill of the coarse-grained material is carried out by segregation of different-grained rocks as a result of unloading of mining equipment at the upper edge of the pit sides. 3. The method according to claim 1, characterized in that the flattening of the sides until reaching the angle of repose is carried out above the minimum water level in the pit.

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