RU2365703C1 - Prevention method of liquid contaminations frontal advance in formation massif - Google Patents

Abstract

FIELD: mining engineering.

SUBSTANCE: invention relates to mineral resource industry and other field, where it is possible environmental pollution by liquid compounds, process waters or it is observed feeding of polluted water into mine openings. Method includes construction of hydraulic screen perpendicularly to flow of polluted water, creating in water-bearing bed by route of hydraulic screen shaft - by means of feeding into stratum of pure water and level lifting in it of subsurface water. By route of hydraulic screen it is constructed linear or circular loop system of injection wells, united by water-feeding pressure conduit. Water-feeding pressure conduit is connected to pump station and is outfitted by doing units of feeding into injected water of compounds contaminations neutralising, and also control system of pressure modes and productivity of water pumping-in.

EFFECT: invention expands range of application hydraulic screens and increases its maintainability.

1 dwg, 1 ex

Description

The invention relates to the mining industry and x other industries where environmental pollution by liquid compositions is possible.

From the current technical level it is known to use a hydraulic curtain to prevent pollution of groundwater by various effluents containing harmful ingredients, filtration losses from liquid waste storage devices (Makunev M.N., Prozhivin V.V., Method for preventing groundwater pollution. Patent of the Russian Federation 2052575, Date of publication of the claims 1996.01.20).

Similar inventions are also known: Japanese Patent No. 45-38034, class. 88 B1, 1971; USSR Copyright Certificate No. 1030469, Е02В 3/16, 1983; USSR copyright certificate No. 1382901, cl. ЕВВ 3/16, 1988, RF Patent No. 2163957 С2, 7 Е03В 3/06, 1999, containing “A method for eliminating polluted groundwater”, as well as the work of G. Korotkevich Groundwater protection and management of their regime by applying the methods of hydraulic curtains and pneumocollating. "News of the Leningrad University", 1976, No. 18.

As a prototype for the totality of essential features, the method of constructing a hydraulic curtain to prevent groundwater pollution according to the invention patent RU 2052575 C1, 3/02 3/16, Makunev MN, Pozhivin VV was selected. A way to prevent groundwater pollution.

The method involves driving a trench perpendicular to the harmful impurities from the source of pollution migrating with the flow of groundwater. In order to provide hydraulic communication with the aquifer, injection wells are being constructed in the trench. The trench is then filled with water, for which substandard water is used from the production wells of the water intake or from the surface water source according to the stipulated operating mode to form the necessary pressure gradient between the water intake and the hydraulic curtain. A consequence of the fulfillment of these conditions is the formation of a dynamic hydraulic curtain, which allows you to create a barrier to the movement of pollution and replenish water reserves of the water intake.

In practice, the method is as follows. Below the source of pollution, a channel deepened to a water-resistant layer is torn off normally from the groundwater flow. To provide hydraulic communication between the channel and the aquifer, a series of absorbing wells are drilled along the channel axis. Water is supplied to the canal from water wells or ground water sources (rivers, lakes). At the same time, a shaft of feed water is formed along the channel in the aquifer, which prevents further movement of polluted waters.

The disadvantages of the prototype are:

- a significant amount of earthwork during the construction of the canal;

- the difficulties of creating a hydraulic curtain with a deep occurrence of an aquaculture, a high position (close to the surface) of groundwater levels;

- significant difficulties in the construction of a hydraulic curtain with significant differences in surface elevations, which necessitates an increase in the depth of the channel or its collapse;

- great difficulties when crossing the curtain of surface watercourses (rivers, canals, open drains, etc.);

- the need for fixing the walls of the channel;

- water loss due to evaporation from the channel;

- getting into the channel of pollution with dust, rain flows due to the human factor;

- siltation of the channel in time and the need for its cleaning;

- colmatation of filters and bottom-hole zones of absorbing wells and work on their regeneration, repair;

- the inability to vary the pressure (pressure) of the water supplied to the curtain;

- the almost impossibility of using these hydraulic curtains in high-pressure aquifers and in built-up areas;

- limited period of maintenance-free operation, lack of reliability;

- the need to organize protection against intentional water pollution.

The aim of the invention is to develop a design and technology for creating a hydraulic curtain, preventing the entry of contaminated water into the environment, mining and water intakes, devoid of the noted disadvantages of the prototype.

The solution to this problem was made possible due to the fact that in the known method of protection against the promotion of pollution, in a hydraulic curtain comprising a distribution open water supply channel, instead of the latter, a distribution pipe 1 is placed between the pollution source and the mine workings 3 or the water intake, to which all injection wells 2 are connected ( see drawing). The specified pressure pipeline to the injection wells serves clean water with the required design pressure and flow rate. In order to enhance the efficiency of the hydraulic curtain, compositions (chemical reagents) capable of neutralizing or weakening the effect of contaminating components can be supplied to the injected water through a dispenser.

The hydrodynamic justification of the hydraulic curtains is a rather delicate task of underground hydraulics, since the mode of water injection into injection wells should be such that a line is formed between the leach section and the line of the hydraulic curtain 1, at which point the velocities of the underground flow should be equal in magnitude but opposite in direction .

The method of hydrogeological calculation of a hydraulic curtain is described in sufficient detail in the work of A. Izotov. and Chuyko V.M. (Calculation of the injection mode when creating hydraulic curtains in order to localize technological solutions. Abstracts at the regional scientific and technical conference. Belgorod: VIOGEM, 1979).

Technical results that can be obtained using the invention are:

- independence of the proposed technology for the construction of a hydraulic curtain on the nature of the relief, the depth of the aquifer, the pressure of groundwater;

- the exception of earthwork, fixing the walls of the channel, its deboning, cleaning, etc .;

- eliminating the possibility of contamination of injected water;

- expanding the scope of the hydraulic curtain: to prevent the loss of technological solutions during the development of deposits by underground leaching, to protect coastal quarries and other workings from seawater, to localize sources of environmental pollution by industrial effluents (reservoirs, sedimentation tanks, sludge and tailings);

- preventing the influx of acidic or other composition of process water into the mine workings with a combined method of mining deposits;

- the possibility of intensifying the process of replenishing water resources;

- improving the reliability and durability of the hydraulic curtain of the proposed design (technological scheme).

The practical applicability of the claimed method of constructing a hydraulic curtain is shown in the following example.

The hydraulic curtain 1 is actually implemented on an ore formation deposit, which is confined to a shallow formation of weakly cemented sandstones. The productive layer is allocated in an independent pressure horizon. The average thickness of sandstones is 25 m, the depth of their occurrence is 180-200 m, the water pressure above the soil of the formation is 120-140 m, the average value of the filtration coefficient is 4 m / day, the specific flow rates of injection wells were in the range 0.0005-0.002 m ³ / s. The field was developed in a combined way: a system of underground mining 3 and the method of underground leaching (PV). The distance between the underground mine and the PV section is 1.6 km. As a leaching reagent, solutions of sulfuric acid are used. Under the influence of the drainage of the mine, the sulfate solutions advanced 800 m in the direction of the mine over the course of 5 years. A line of seven injection wells 2 was connected to the front line of the advancement of technological solutions 4, connected to one system by a pressure pipe 1 from the pump station. For injection, the drainage water of the underground mine 3 was used. The injection was carried out at a pressure of 0.4-1.0 MPa with a total capacity of 0.116-0.133 m ³ / s. Hydroisopies 5 of the aquifer during operation of the hydraulic curtain are shown in the drawing. The main information on the wells of the constructed hydraulic curtain is given in Table 1.

Table 1 Squeen Number Depth N, m Diameter of drilling, mm Filter Information Pickup, m ³ / s Diameter mm Installation Interval, m Duty rate,% maximum at p = 1 MPa average for 14 months of work one 2 3 four 5 6 7 8 AT 4 211 490 325 158-191 fifteen 0,053 0,022 AT 5 207 - "- - "- 156-186 - "- 0.058 0,025 AT 6 192 - "- - "- 128-172 - "- 0,043 0,025 AT 7 194 - "- - "- 136-172 - "- 0,025 0.018 AT 9 205 - "- - "- 146-184 - "- 0.017 0.008 AT 10 201 - "- - "- 151-182 - "- 0,037 0.016 B-1 203 190 127 153-182 17 0.004 0.002

Below are the data on the parameters of the hydraulic curtains:

Delivery rate Q, m ³ / day 2040 Slope i 0,036 The coefficient of reservoir filtration K, m / day four Formation thickness m, m 25 The distance between the wells δ, m 300 Active porosity of rocks, n 0.15 The distance to the branching point of the stream At _A , m 210 Time of advancement of the front of neutral water t, days 260

To evaluate the effectiveness of the hydraulic curtain, we used the data of observations, chemical analyzes and geophysical measurements for observation wells 6 located on both sides of the hydraulic curtain.

An analysis of the observation results showed that the displacement of sulfuric acid solutions by neutral water is quite intense, the interface of 7 acidic and neutral waters has moved 100 m upstream. Over 260 days of operation of the hydraulic curtain, 100 m from the hydraulic curtain upstream, the acidified zone power decreased from 7.3 m to 2.3 m, and the pH increased from 1.9 to 5.8 (see the position of isolines pH 8). At a distance of 200 m downstream, the acidification zone power decreased from 5.3 m to 2.1 m, and the pH increased from 3.0 to 5.5. Thus, the use of a hydraulic curtain proved to be an effective measure to prevent the front of sulfate solutions from advancing to an underground mine.

Claims (1)

A method of preventing the advancement of liquid contaminants in a rock mass, including the construction of a hydraulic curtain perpendicular to the flow of contaminated water, creating a shaft in the aquifer along the hydraulic curtain path by supplying clean water to the reservoir and raising the level of groundwater in it, characterized in that a hydraulic curtain is constructed along the hydraulic curtain path a linear or circular closed system of injection wells, combined by a water supply pressure pipe, which is connected to a pumping station and equipped with dispensers for supplying to the pump Ty water pollution neutralizing compositions and mode control system pressures and performance of water injection.

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