Combined method of underground mining of potassium and potassium-magnesium salts

Abstract

FIELD: mining.SUBSTANCE: proposed invention relates to combined methods of underground extraction of potassium and potassium-magnesium salts. The combined method of underground mining of potassium and potassium-magnesium salts is characterized by the fact that two vertical mine shafts with a diameter of up to 6 m are constructed, one of which is a skip-cage with injection and production pipelines located in it, and the other is a ventilation one, then a shaft yard is constructed comprising many mine workings and located in stable layers of cap rock salt in the roof of the productive layer 10-80 m above the productive layer of potassium and potassium-magnesium salts, preparing for cleaning excavation, including drilling a grid of boreholes from the mine workings vertically downwards into the productive layer of potassium and potassium-magnesium salts, pumping water – a solvent and diesel fuel – a non-solvent into the productive layer, creating chambers for underground dissolution of salts, organizing the dissolution of salts in the above chambers, cleaning excavation, including pumping out saturated brines from the underground salt dissolution chambers through brine pipelines to the shaft yard and hydraulic lifting by a pumping station through the production pipelines of the vertical shaft of the mine to the daylight surface to the concentrator, and the subsequent hydraulic lowering of the backfill mixture, which is the tailings of the concentrator, through the injection pipelines of the vertical shaft and through the network of mine workings into the empty underground salt dissolution chambers for their complete backfill.EFFECT: intensification of production and simplification of the implementation of the method of underground production of potassium and potassium-magnesium salts.1 cl, 3 dwg, 1 tbl

Description

[0001] The present invention relates to mining, in particular to combined methods for underground mining of potassium and potassium-magnesium salts [E21B 43 / 28].

[0002] The main methods of underground mining of potassium and potassium-magnesium salts are the mine method and the underground salt solution (ISS) method (leaching).

[0003] Potassium salt mining began in Strassfurt, Germany in 1851 with the construction of two mining shafts, Von der Heydt and Von Manteuffel.

[0004] In Russia, the mining of potassium salts began in 1925-1926 at the Verkhnekamskoye deposit with the development of powerful potassium seams in the area of ​​the cities of Solikamsk and Berezniki.

[0005] An example of a method of shaft mining can be found in patent publication RU2015111943A, published on 20.10.2016, which discloses a method for opening a mine field using vertical shafts.

[0006] Disadvantages of this method: high economic and time costs for the construction of vertical mine shafts with a diameter of 8 m or more (3-5 years or more, depending on the depth and mining and geological conditions), the risk of flooding and loss of the mine when mining operations violate the water-protective layer, the involvement of a large amount of mining equipment (skip hoist, conveyor transport, cleaning and tunneling machines, loading wagons, loaders and haul trucks, etc.), the risk of people being present in the mine during the excavation of workings and stopes and in other places where mining operations are carried out, a low coefficient of extraction of the useful component (30-40%).

[0007] An example of a method for underground dissolution of salts (leaching) can serve as patent publications US2161800A, published 13.06.1939, RU2472927C2, published 20.01.2013, RU2065037C1, published 10.08.1996, RU2081309C1, published 10.06.1997, RU2095556C1, published 10.11.1997, RU2190764C2, published 10.10.2002, RU2306417C2, published 20.01.2007.

[0008] In all the known methods mentioned, vertical production wells for opening the productive formation and supplying solvent (water) under pressure for underground dissolution of salts are constructed from the surface of the earth.

[0009] Disadvantages of these methods: high economic and time costs for the construction of vertical production wells to the productive formation of potassium salts (for example, at a depth of 600 m, the drilling and construction time of one well can be 10-14 months), high supporting capital costs for the replenishment of wells decommissioned (every three to four years, drilling of new wells with a productive formation thickness of up to 30 m), the need to use the entire surface area of ​​the field for drilling sites for production wells, high environmental risks in the event of brine spills from surface pipelines.

[0010] The closest in technical essence is the method of borehole extraction of mineral salts [RU2236577C1, published 09.20.2004], which includes drilling two or more wells from the earth's surface, casing them, equipping them with working pipes, feeding a solvent and a non-solvent into the deposit, pumping out the brine, forming a preparatory working, and washing out the chamber.

[0011] The disadvantage of this method is its low efficiency and the duration of the process due to the need to drill a large number of vertical wells to a great depth (more than 600 m) and the insufficient intensity of the process of producing brine at the initial stage.

[0012] The objective of the invention is to create an effective technology for borehole extraction of potassium and potassium-magnesium salt brines from underground workings located in stable overlying rocks at a minimum distance from the productive formation of potassium salts, eliminating human presence in the production zone.

[0013] Technical result – intensification of production and simplification of the implementation of the method of underground extraction of potassium and potassium-magnesium salts due to the reduction of the time and costs of drilling instead of deep (more than 600 m) from the surface of the earth, shallow wells (up to 80 m) – from a mine working – a drift and the formation of vertical cleaning dissolution chambers in the thickness of the productive formation of potassium salts.

[0014] The specified technical result is achieved due to the fact that the combined method of underground mining of potassium and potassium-magnesium salts is characterized by the fact that the construction of two vertical mine shafts, up to 6 m in diameter, one of which is a skip-cage with injection and production pipelines located in it, and the other is a ventilation one, then the construction of a shaft yard is carried out, containing a plurality of mine workings and located in stable layers of cap rock salt in the roof of the productive layer 10-80 m above the productive layer of potassium and potassium-magnesium salts, preparation for cleaning excavation, including drilling a grid of wells from the mine workings vertically downwards into the productive layer of potassium and potassium-magnesium salts, pumping water - a solvent and diesel fuel - a non-solvent into the productive layer, creating chambers underground dissolution of salts, organization of dissolution of salts in the above-mentioned chambers, cleaning of the excavation,including pumping saturated brines from the underground salt dissolution chambers through brine pipelines to the shaft yard and hydraulic lifting by a pumping station through the production pipelines of the vertical shaft of the mine to the daylight surface to the processing plant, and the subsequent hydraulic lowering of the backfill mixture, which is the tailings of the processing plant through the injection pipelines of the vertical shaft and through the network of mine workings - into the empty underground salt dissolution chambers for their complete backfill.

[0015] Brief description of drawings.

[0016] Figure 1 shows a diagram of the implementation of a combined method of underground mining of potassium and potassium-magnesium salts.

[0017] Figure 1 shows the diagram of the first stage of development of a potash and potassium-magnesium deposit with 100 wells of the PRS (for a production volume of 1 million tons per year, calculated as 100% KCl for 3-4 years of operation).

[0018] Figure 3 shows a diagram of the cleaning extraction of brine from a potash deposit in the 4th stage over a given area of ​​the potash deposit (for 9-12 years of operation, conditionally 9-12 million tons in terms of 100% KCl).

[0019] The figures show: 1 and 2 - vertical shafts of the mine, cage and ventilation; 3 - a system of injection pipelines for solvent-water, non-solvent (diesel fuel), backfill material - tailings of the processing plant; 4 - a system of pipelines for transporting mined brine; 5 - productive stratum of potassium and potassium-magnesium salts of the deposit; 6 - sectional drifts; 7 - day surface of the earth; 8 - pumping station for injection of solvent, non-solvent and tailings of the processing plant for backfilling of underground salt dissolution chambers; 9 - underground salt dissolution chambers (caverns); 10 - pumping station for hydraulic lifting of brine to the day surface at the processing plant; 11 - processing plant; 12 - pipelines for feeding tailings (waste) from the processing plant into empty chambers for underground salt dissolution;13 - unit for feeding tailings (waste) from the processing plant into the pipeline system in the mine shaft and further into the empty chambers of underground salt dissolution; 14 - central pipe for injecting solvent and non-solvent into the chambers of underground salt dissolution; 15 - internal cavity between the central pipe and casing pipe for feeding brine from the chambers of underground salt dissolution into the drifts and further onto the daylight surface to the processing plant; 16 - casing pipe; Nos. 1-50 - numbers of the chambers of underground salt dissolution; Нг - depth from the daylight surface of the earth to the ceiling of the section drift, 600 meters or more; Нш - height of the section drift - 3 m; Нн - thickness of rock from the bottom of the section drift to the productive stratum of potassium salts.

[0020] Implementation of the invention.

[0021] The following describes a preferred embodiment of the method for combined underground mining of potassium and potassium-magnesium salts in accordance with the present invention, illustrated in Figure 1.

[0022] At the initial stage of the claimed method, the construction of two small-diameter vertical shafts 1 and 2 is carried out to open up the deposit.

[0023] More specifically, the construction phase of two small shafts involves the construction of a small underground mine with two vertical shafts (1 and 2) of small diameter, in particular up to 6 meters. One of these shafts (1) is a skip-cage shaft designed for lowering and raising equipment and personnel, removing waste rock from mining workings, and housing injection 3 and production 4 pipelines; the other (2) is a ventilation shaft for the outgoing air flow, lowering and raising personnel and equipment, and housing pipelines and cables. Both shafts are constructed to the depth of the upper potash seam or the cap rock salt layer.

[0024] Afterwards, a shaft yard containing a multitude of mine workings, main direction workings, panels and block sectional drifts 6 is constructed using a combine method.

[0025] The stage of mine field preparation includes the construction of shaft yard workings, main directions and panels, block and sectional drifts 6 in stable layers of overlying rock salt in the roof of the productive stratum above the productive stratum 5 of potassium and potassium-magnesium salts.

[0026] More specifically, the shaft yard workings are located in stable layers of cap rock salt in the roof of the productive layer 10-80 m above the productive layer of 5 potassium and potassium-magnesium salts.

[0027] Next, they begin the implementation of the preparation stage for the cleaning excavation.

[0028] The preparation stage for cleaning excavation includes the following sub-stages:

[0029] – drilling a 200x200 m grid of shallow (10 to 80 m) wells from development workings (6 sectional drifts) vertically downwards into the productive layer of 5 potassium and potassium-magnesium salts;

[0030] – pumping of water-solvent and diesel fuel-non-solvent into the productive layer 5 of potassium and potassium-magnesium salts by pumping station 8;

[0031] – creation of 9 underground salt dissolution chambers;

[0032] – organization of salt dissolution in chambers 9 of underground salt dissolution.

[0033] In particular, as illustrated in Figure 2, the preparation for a 100-well cleaning operation is characterized by a well grid of 200x200m and a total site area of ​​4x1.150=4.6 km 2 =46.0 ha.

[0034] Then they begin to implement the stage of cleaning excavation, and the said stage includes the following sub-stages:

[0035] – pumping / lifting brine from the chambers 9 for underground salt dissolution through the space 15 between the central injection pipe 14 and the casing pipe 16 into the drift 6;

[0036] – transportation of saturated brines through brine pipelines located in preparatory workings to the shaft yard;

[0037] – hydraulic lifting by pumping station 10 through the production pipeline system 4 of vertical shaft of mine 1 to the daylight surface 7 to the processing plant 11;

[0038] – hydraulic lowering of the filling mixture, which is the tailings of the processing plant 11, fed through the pipeline 12 to the tailings feeding unit 13, and then through the pipeline system 3 along the vertical shaft and through the network of mine workings – into the empty chambers 9 of the underground dissolution of salts;

[0039] – complete filling of chambers 9 for underground dissolution of salts with tailings of processing plant 11.

[0040] The inlet and outlet pipelines of the wells of the 9 underground salt dissolution chambers are also equipped with valves that regulate the supply of water / tailings and the intake of brine, which are not shown in the figures.

[0041] The grid of production wells 200x200 m is made in a rectangular shape (Fig. 2), to the left and right of the cutting drifts there are 50 wells - 5 rows of 10 wells each. The total area of ​​​​potash salt production for 100 wells is 4000 m x 1150 m in length and width = 4,600,000 m 2 = 460 hectares = 4.6 km 2 .

[0042] The proposed well grid, after the development (dissolution) of the first stage of 100 wells over 3-4 years (Fig. 2), allows for the construction of the 2nd, 3rd and 4th stage of wells between these wells (Fig. 3) and their sequential development over the next 9-12 years. The maximum complete extraction of potassium and potassium-magnesium salts in the specified area with a recovery factor of up to 80-90% is achieved by filling the free spaces of the chambers 9 for underground salt dissolution and performing subsequent reverse mining of the areas of the inter-chamber pillars.

[0043] The combined underground potash mining method described above can be implemented at six sites within the potassium-magnesium salt deposit in the Perelyubsky District of the Saratov Region: Zapadno-Perelyubsky, Vostochno-Perelyubsky, Tsentralno-Ivanikhinsky, Zapadno-Ivanikhinsky, Zapadno-Tselinny, and Vostochno-Tselinny. When implementing the proposed method at these sites over a 24-year period, the surface area of ​​the facility and underground mining area would occupy less than 5% of the deposit's area (with a capacity of 1 million tons per year, calculated as 100% KCl).

[0044] Other advantages of implementing the claimed method for underground extraction of potassium salts in comparison with known methods from the prior art, characterized by drilling a grid of wells from the surface, are presented in the Table.

[0045] Table

[0046] № Compared methods Neutralizable disadvantages of known methods of surface and underground (mine) extraction of potassium and potassium-magnesium salts The advantages of the declared combined method of underground mining of potassium and potassium-magnesium salts with PRS 1 Use of the entire field area for well sites Standard industrial site, no well pads available 2 Construction and maintenance of technological roads between well sites There is no need for technological roads between well sites 3 Network of brine pipelines on the surface There are no brine pipelines on the surface 4 Environmental risks of accidents in the brine pipeline network on the surface There is no brine pipeline network on the surface 5 The high cost of drilling wells to a depth of 600 m or more Low cost of drilling wells 10-80 m deep 6 High maintenance level of capital expenditures for replenishment of producing wells Low maintenance capital expenditure 7 Drilling time for 1 well (600 m – 1 year) Minimum drilling time for 1 well (10-80 m - 1 day) 8 The influence of seasonality on surface production (variable temperature regime) No seasonality (constant temperature conditions in the workings)

[0047] This combined method of underground mining of potassium salts can also be used in the development of other potassium and potassium-magnesium deposits.

[0048] With the proposed combined underground mining method, only the processing plant and a small portion of the underground mine's water supply lines will remain above ground. Furthermore, the surface network of technological roads between the facilities and the brine pipeline network will be eliminated.

[0049] The main areas of the extraction pit for 100 production wells (1 million tons per year in terms of 100% KCl for 3-4 years) with a well grid of 200x200m and a total area of ​​4x1.150 = 4.6 km 2 =46.0 hectares, will be located underground.

[0050] The technical result of the invention - intensification of production and simplification of the implementation of the method of underground mining of potassium and potassium-magnesium salts - is achieved due to the fact that two vertical mine shafts 1 and 2 are built, with a diameter of up to 6 m, one of which is a skip-cage with injection and production pipelines located in it, and the other is a ventilation one, then a shaft yard is built containing a plurality of mine workings and located in stable layers of cap rock salt in the roof of the productive stratum 5 by 10-80 m above the productive stratum 5 of potassium and potassium-magnesium salts, preparation for cleaning excavation, including drilling a grid of wells from the mine workings vertically downwards into the productive stratum 5 of potassium and potassium-magnesium salts, pumping water - solvent and diesel fuel - non-solvent into the productive layer 5, creation of chambers 9 for underground dissolution of salts,organizing the dissolution of salts in the above-mentioned chambers 9, cleaning the excavation, including pumping out saturated brines from the chambers 9 for underground dissolution of salts through brine pipelines to the shaft yard and hydraulic lifting by pumping station 10 through the production pipelines of the vertical shaft of the mine to the daylight surface 7 to the processing plant 11, and subsequent hydraulic lowering of the filling mixture, which is the tailings of the processing plant 11 through the injection pipelines of the vertical shaft and through the network of mine workings - into the empty chambers 9 for underground dissolution of salts for their complete filling.

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