A method of uranium mining from sandstone uranium deposits

Abstract

The present application relates to a kind of sandstone uranium mining method of uranium mining.The method includes: according to the interval between the interval between liquid pumping well and liquid injection well and the permeability of stratum is determined, and according to the thickness of ore bed determines four perforation segments;One liquid pumping well and one liquid injection well correspond to four perforation segments;And each of the perforation segment corresponds to the direction of surrounding well;When indicating the perforation segment on the liquid pumping well, the surrounding well is liquid injection well, when indicating the perforation segment on the liquid injection well, the surrounding well is liquid pumping well;The length of the perforation segment is obtained and is perforated, and according to the length of the perforation segment, the liquid pumping well and the liquid injection well are fractured from bottom to top, until the direction of four perforation segments on any well is fractured;Injection agent is injected into the liquid injection well after fracturing, and leaching solution is extracted from the liquid pumping well after fracturing;The leaching solution is treated, and uranium product is obtained.The present application reduces the cost while improving the permeability, and improves the uranium leaching amount.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of in-situ leaching of uranium, in particular to a method for mining uranium from sandstone uranium deposits. BACKGROUND

[0002] In-situ leaching of uranium has become the most important method for mining natural uranium in China. Due to the poor endowment of sandstone uranium resources in China, there are many difficult conditions such as low permeability, superimposed multiple ore bodies, small ratio of ore body thickness to sand body thickness, large buried depth of ore body, high degree of groundwater mineralization, and uranium-coal superposition. In particular, the amount of low-permeability sandstone uranium resources is large, which is difficult to economically exploit. It is an inevitable trend to use effective means to improve the permeability of low-permeability sandstone uranium or to improve the permeability of the ore bed within a certain range near the wellbore to achieve economic exploitation.

[0003] Numerous studies on permeability improvement techniques have been conducted for low-permeability sandstone uranium deposits. For example, acidizing (CN104533376B), hydrojet (201511026941.3), ultrasonic (201810809145.4), surfactants, perforating, and other permeability improvement techniques have been studied by drawing on oil exploitation techniques to improve the permeability near the wellbore. Some results have been achieved in practice. However, these methods generally have a small range of action and can only partially improve the original permeability or alleviate the reduction in permeability during in-situ leaching of uranium and remove damage, and cannot achieve the effect of improving permeability and greatly improving the original permeability.

[0004] The characteristics of low-permeability sandstone uranium reservoirs determine that they are difficult to be economically in-situ leached, and the permeability of the ore bed must be improved. Similarly, in the face of low-permeability and ultra-low-permeability deposits (which can be as low as 0.01 m / d or lower), the oil, shale gas, coalbed methane, and hydraulic salt mining industries have widely applied reservoir reconstruction techniques such as fracturing. The most widely used technique is hydraulic fracturing, which injects fracturing fluid into the wellbore at a high flow rate to crack the formation and cause cracks to extend along the direction of the maximum principal stress to form high-conductivity support fractures up to tens of meters or even hundreds of meters long, thereby improving the permeability of the reconstructed area.

[0005] However, in-situ leaching of uranium is a chemical mining process that involves not only the flow of the solution and the diffusion of the solute but also the chemical reaction between the leaching agent and the minerals, which is a coupling of physical and chemical fields. The long and large fractures with significant geometric dimensions in the above industries can cause preferential flow of the leaching solution, making it difficult to leach uranium resources in the non-preferential flow area. SUMMARY

[0006] The purpose of the present application is to provide a method for mining uranium from sandstone uranium deposits to greatly improve the permeability of the ore bed, increase the amount of fluid injection and extraction, and accelerate the leaching speed, and to solve the problems of poor leaching efficiency and low recovery rate in the fracturing mining of low-permeability sandstone uranium deposits using long and large fractures with significant geometric dimensions.

[0007] To achieve the above object, the present application provides the following scheme:

[0008] A method for mining uranium from sandstone uranium deposit, comprising:

[0009] The interval between the liquid pumping well and the liquid injection well is determined according to the stratum depth and the stratum permeability, and the four perforation sections are determined according to the ore bed thickness; one liquid pumping well and one liquid injection well correspond to the four perforation sections; each perforation section corresponds to the direction of the surrounding well; when the perforation section on the liquid pumping well is represented, the surrounding well is the liquid injection well, and when the perforation section on the liquid injection well is represented, the surrounding well is the liquid pumping well; the interval between the liquid pumping well and the liquid injection well is 30m-50m when the depth of the liquid pumping well and the liquid injection well is 300m-500m, and the interval between the liquid pumping well and the liquid injection well is 35m-60m when the depth of the liquid pumping well and the liquid injection well is 500m-800m;

[0010] The length of the perforation section is obtained and the perforation is performed, and then the liquid pumping well and the liquid injection well are fractured from bottom to top according to the length of the perforation section, and the fracturing range is controlled to be 5m-10m in radial length through the displacement and the fracturing fluid volume until the directional fracturing of the four perforation sections on any well is completed;

[0011] The leaching agent is injected into the liquid injection well after the fracturing is completed, and the leaching solution is pumped out from the liquid pumping well after the fracturing is completed;

[0012] The leaching solution is treated to obtain the uranium product.

[0013] Optionally, the length of the perforation section is 0.3m-1.0m, and the interval between adjacent perforation sections is 0.3m-1.0m.

[0014] Optionally, the fracturing of the liquid pumping well and the liquid injection well from bottom to top according to the length of the perforation section specifically comprises:

[0015] According to the length of the perforation section, two packers with an upper and lower interval longer than the length of the perforation section are sleeved on the casing; the packers are connected to the fracturing facilities;

[0016] The fracturing range is controlled through the displacement and the fracturing fluid volume;

[0017] Based on the fracturing range, the fracturing of the liquid pumping well and the liquid injection well from bottom to top is performed by using the packers.

[0018] Optionally, after the length of the perforation section is obtained and the perforation is performed, and then the liquid pumping well and the liquid injection well are fractured from bottom to top according to the length of the perforation section until the directional fracturing of the four perforation sections on any well is completed, the method further comprises:

[0019] obtaining injection liquid volume of the injection well before fracturing, obtaining extraction liquid volume of the extraction well before fracturing, obtaining injection liquid volume of the injection well after fracturing, and obtaining extraction liquid volume of the extraction well after fracturing;

[0020] comparing the injection liquid volume of the injection well before fracturing with the injection liquid volume of the injection well after fracturing to obtain injection liquid comparison result;

[0021] comparing the extraction liquid volume of the extraction well before fracturing with the extraction liquid volume of the extraction well after fracturing to obtain extraction liquid comparison result;

[0022] evaluating the permeation enhancement effect after fracturing according to the injection liquid comparison result and the extraction liquid comparison result;

[0023] if the permeation enhancement effect is within the set permeation enhancement range, injecting the leaching agent into the injection well after fracturing and extracting the leaching liquid from the extraction well after fracturing;

[0024] if the permeation enhancement effect is not within the set permeation enhancement range, adjusting the length of the perforation section and re-performing fracturing.

[0025] Optionally, the leaching liquid is treated to obtain a uranium product, specifically comprising:

[0026] the leaching liquid is adsorbed by ion exchange adsorption resin to generate saturated resin and adsorption tail liquid;

[0027] the saturated resin is eluted by eluent to obtain uranium-containing qualified liquid;

[0028] the uranium-containing qualified liquid is precipitated to obtain a uranium product.

[0029] Optionally, the leaching liquid is adsorbed by ion exchange adsorption resin to generate saturated resin and adsorption tail liquid, and then further comprising:

[0030] the adsorption tail liquid is added with the leaching agent and re-injected into the ore bed through the injection well after fracturing.

[0031] According to the specific embodiments of the present application, the present application discloses the following technical effects: the present application provides a method for mining uranium in sandstone uranium mine, four perforation sections are arranged on the extraction well and the injection well, small-scale micro-fracturing is used to form fractures around the wellbore in a small range, which does not cause the preferential flow of leaching liquid, thereby improving the permeability while reducing the cost, and facilitating mining; the micro-fracturing operation ensures the leaching effect and improves the uranium leaching amount; in addition, the present application adopts a simple well structure, combines with micro-fracturing measures, increases the distance between the extraction well and the injection well, and significantly reduces the drilling cost. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only illustrate some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 It is a diagram for the influence of the fracturing radius on the leaching area.

[0034] Figure 2 It is a flow chart of the method for extracting uranium from sandstone uranium ore provided by the present application.

[0035] Figure 3 It is a perforation section design diagram provided by the present application.

[0036] Figure 4 It is a diagram for the fracturing effect provided by the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application.

[0038] The present application aims to provide a method for extracting uranium from sandstone uranium ore, which can improve the permeability while reducing the cost, ensure the leaching effect and improve the uranium leaching amount.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0040] Embodiment one

[0041] Figure 1 It is a diagram for the influence of the fracturing radius on the leaching area. From the perspective of the plane influence area of fracturing, the radial length of the crack, i.e. the circumferential radius r is between 5-10 m, and the influence area S is only 78.5-314 m 2 For the pumping and injection unit with a pumping and injection well spacing L of 30-60 m and an area of 1800-7200 m 2 , the area of the fracturing zone is controlled within 10%, and considering the high reagent concentration in the injection zone and the good leaching effect, the leaching rate of more than 70% in the fracturing zone can be realized.

[0042] Figure 2 It is a flow chart of the method for extracting uranium from sandstone uranium ore provided by the present application, asFigure 2 Based on the influence of the fracturing radius on the leaching area, the uranium mining method of the sandstone uranium mine comprises the following steps:

[0043] Step 201: Determine the interval between the liquid pumping well and the liquid injection well according to the stratum depth and the stratum permeability, and determine four perforation sections according to the ore bed thickness; one liquid pumping well and one liquid injection well correspond to four perforation sections; each perforation section corresponds to the direction of the surrounding well; when the perforation section on the liquid pumping well is represented, the surrounding well is the liquid injection well, and when the perforation section on the liquid injection well is represented, the surrounding well is the liquid pumping well; the interval between the liquid pumping well and the liquid injection well is 30-50 m when the depth of the liquid pumping well and the liquid injection well is 300-500 m, and the interval between the liquid pumping well and the liquid injection well is 35-60 m when the depth of the liquid pumping well and the liquid injection well is 500-800 m.

[0044] Step 202: Obtain the length of the perforation section and perform perforation, and then perform fracturing construction from bottom to top on the liquid pumping well and the liquid injection well according to the length of the perforation section until the fracturing in the four directions of any well is completed.

[0045] The fracturing construction from bottom to top on the liquid pumping well and the liquid injection well according to the length of the perforation section specifically comprises the following steps: according to the length of the perforation section, two packers with an upper and lower interval longer than the length of the perforation section are sleeved on the casing; the packers are connected to fracturing facilities; the fracturing range is controlled by displacement and fracturing fluid volume; and the fracturing construction from bottom to top on the liquid pumping well and the liquid injection well is performed based on the fracturing range.

[0046] According to the ore bed thickness, the four perforation sections are divided, each perforation section 0.3-1.0 m corresponds to the direction of one surrounding well in the southeast, southwest and northwest directions, and each perforation section is 0.3-1.0 m long; the adjacent perforation sections are spaced apart by 0.3-1.0 m. Figure 3 As shown in the figure, the packer sealing and layered fracturing are ensured; drilling, casing lowering and reverse grouting are performed, and well perforation is completed.

[0047] In actual application, according to the length of the perforation section, two packers with an upper and lower interval 0.1-0.5 m longer than the length of the perforation section are sleeved on the casing. The packers are lowered, the fracturing facilities are installed and connected, and the fracturing construction is performed from bottom to top. The fracturing range is controlled to be 5-10 m in radial length. Then the packer is unsealed, the previous layer is lifted, the previous layer perforation section is fractured, and the fracturing in the four directions is completed, as shown in the figure. Figure 4

[0048] In actual application, after the fracturing operation is completed, the permeability improvement effect is evaluated by comparing the changes in the liquid pumping amount of the liquid pumping well and the liquid injection amount of the liquid injection well before and after the modification, and the design and construction quality are confirmed.

[0049] ​Further, the step of obtaining the length of the perforation section and perforating, and then fracturing the injection well and the production well from bottom to top according to the length of the perforation section until the fracturing of any well in the four perforation section directions is completed, further comprises: obtaining the injection volume of the injection well before fracturing, the production volume of the production well before fracturing, the injection volume of the injection well after fracturing, and the production volume of the production well after fracturing; comparing the injection volume of the injection well before fracturing with the injection volume of the injection well after fracturing to obtain an injection comparison result; comparing the production volume of the production well before fracturing with the production volume of the production well after fracturing to obtain a production comparison result; evaluating the enhanced permeability effect after fracturing according to the injection comparison result and the production comparison result; if the enhanced permeability effect is within a set enhanced permeability range, injecting the leaching agent into the injection well after fracturing and extracting the leaching solution from the production well after fracturing; if the enhanced permeability effect is not within the set enhanced permeability range, adjusting the length of the perforation section and re-fracturing.

[0050] Step 203: injecting the leaching agent into the injection well after fracturing and extracting the leaching solution from the production well after fracturing.

[0051] Step 204: processing the leaching solution to obtain a uranium product.

[0052] In actual application, the step 204 specifically comprises: adsorbing the leaching solution by using ion exchange adsorption resin to generate saturated resin and adsorption tail liquid; eluting the saturated resin by using an eluent to obtain a qualified liquid containing uranium; and precipitating the qualified liquid containing uranium to obtain a uranium product.

[0053] The step of adsorbing the leaching solution by using ion exchange adsorption resin to generate saturated resin and adsorption tail liquid further comprises: adding the leaching agent to the adsorption tail liquid, re-injecting into the ore bed through the injection well after fracturing, and cyclic leaching until a target leaching rate is reached.

[0054] Example Two

[0055] A sandstone uranium mine has an ore bed buried at a depth of 400m to 450m and a thickness of 3m to 5m, and uses CO2+O2 leaching process for in-situ leaching mining. The ore bed reconstruction and mining method is as follows:

[0056] The distance between the injection well and the production well is 40m; perforation is performed in four sections, and the length of each perforation section is 0.5m to 0.6m, each section corresponding to the direction of a peripheral well, and the adjacent perforation sections are spaced apart by 0.3m to 0.5m.

[0057] According to the drilling well design, drilling, casing, and reverse grouting, the well is formed by perforation.

[0058] Two packers with the length of 0.8m-1.0m are sleeved on the casing, and the perforation section is located in the middle of the two packers. The packers are lowered, and the fracturing facilities are installed and connected. The fracturing is performed from bottom to top. The fracturing range is controlled to be 5m-10m in radial length by the displacement and the amount of fracturing fluid. Then the packers are unsealed, and the upper layer is lifted. The perforation section of the upper layer is fractured, and the fracturing in four directions is completed.

[0059] After the fracturing operation is completed, the liquid pumping rate of the pumping well is increased by 100%-300%, and the liquid injection rate of the injection well is increased by 300%-500%.

[0060] The leaching agent containing O2 and CO2 is injected into the injection well after the permeability is increased, and underground leaching is performed. The oxygen concentration in the initial leaching agent is 400mg / L-500mg / L. When the residual oxygen concentration in the leaching solution is about 10mg / L, the oxygen injection concentration is reduced to 200mg / L-300mg / L. When the leaching rate reaches 60%-70%, the oxygen injection concentration is reduced to 50mg / L-150mg / L until the leaching is completed. The CO2 addition amount in the initial leaching agent is 500mg / L-1000mg / L. When the bicarbonate concentration rises to 1.0g / L, the CO2 addition amount is 100mg / L-500mg / L to adjust the pH value to 6.5-7.5. The leaching agent injection pressure is controlled at 1.0-1.6MPa, and the O2 and CO2 addition pressure is higher than the leaching agent injection pressure by 0.1MPa-0.2MPa.

[0061] When the uranium concentration in the leaching solution is greater than 10mg / L, the ion exchange adsorption resin is used for adsorption. The macroporous styrene-based strong alkaline anion exchange resin is used. After adsorption, saturated resin and adsorption tail liquid are obtained. Two pressure adsorption towers in series are used for forward flow pressure ion exchange adsorption of uranium. The pressure in the first adsorption tower is 0.1MPa-0.3MPa, and the pressure in the second adsorption tower is less than 0.1MPa. When the resin is saturated, the saturated resin is eluted with 15g / L-20g / L NaHCO3 and 80-120g / L NaCl eluent to obtain qualified liquid. The qualified liquid is adjusted to pH 12.0-13.0 with sodium hydroxide, and precipitated at room temperature for 6h-12h. The lower layer is Na2U2O7 precipitate slurry, and the uranium product is obtained by pressure filtration.

[0062] The adsorption tail liquid obtained by treating the leaching solution is injected into the ore bed again through the injection well after CO2 and O2 are added to the above concentrations in the control room, and the circulating leaching is performed until the leaching rate reaches the target and the leaching is completed.

[0063] Example Three

[0064] The ore bed of a sandstone uranium mine is buried at a depth of 550m-650m, and the thickness of the ore bed is 5-8m. The acid leaching process is used for in-situ leaching mining. The ore bed modification and mining method is as follows:

[0065] The distance between the pumping well and the injection well is 50-55m; the perforation is performed in 4 sections, the length of each section is 1.0-1.2m, each section corresponds to the direction of a surrounding well, and the interval between each direction is 0.4-0.8m.

[0066] The drilling, casing and reverse grouting are designed according to the drilled well, and the perforation is performed.

[0067] Two packers with a length of 1.4m are sleeved on the casing, the packers are lowered, the fracturing facilities are installed and connected, and the fracturing is performed from bottom to top. The fracturing range is controlled to be 5-10m in radial length by the discharge and the amount of fracturing fluid. Then the packers are unsealed, one layer is lifted, the perforation section of the upper layer is fractured, and the fracturing in 4 directions is completed.

[0068] After the fracturing operation is completed, the pumping capacity of the pumping well is increased by 150-300%, and the injection capacity of the injection well is increased by 200-400%.

[0069] The leaching agent containing sulfuric acid is injected into the injection well with increased permeability to perform underground leaching; the concentration of sulfuric acid in the initial leaching agent is 1-5g / L; when the pH value of the leaching solution is reduced to 2-3, the concentration of sulfuric acid is increased to 5-10g / L, and hydrogen peroxide is added at the same time, so that the potential is increased to 400-550mV, until the leaching is completed; the injection pressure of the leaching agent is controlled to be 0.5-1.2MPa.

[0070] When the uranium concentration of the leaching solution is greater than 10mg / L, ion exchange adsorption resin is used for adsorption, a macroporous styrene-based strong alkaline anion exchange resin is used, and saturated resin and adsorption tail liquid are obtained after adsorption; two pressure adsorption towers connected in series are used to perform forward flow pressure ion exchange adsorption of uranium, the pressure in the first adsorption tower is 0.1-0.3MPa, and the pressure in the second adsorption tower is less than 0.1MPa; when the resin is saturated, the saturated resin is eluted with 50-90g / L of NaNO3 eluent to obtain qualified liquid; the qualified liquid is adjusted to a pH of 12.0-13.0 with sodium hydroxide, and precipitated at room temperature for 6-12h, the lower layer is Na2U2O7 precipitate slurry, and uranium products are obtained by pressure filtration.

[0071] The adsorption tail liquid obtained by treating the leaching solution is injected into the ore bed again through the injection well after adding sulfuric acid and hydrogen peroxide to the above values in the control room, and the cycle leaching is performed until the leaching reaches the target and ends.

[0072] The present application significantly improves the permeability by small-scale micro-fracturing in a small range around the wellbore, reduces the operation cost and improves the pumping and injection capacity; the present application uses a simple well structure, increases the distance between the pumping well and the injection well, and can significantly reduce the drilling cost and investment; the leaching effect is ensured through the micro-fracturing operation.

[0073] In conclusion, the present application can greatly improve the permeability of the ore bed, increase the injection and extraction volume, accelerate the leaching speed, and realize the economic and recoverable mining of low-permeability sandstone uranium.

[0074] The various embodiments are described in a progressive manner in the specification, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be mutually referred to.

[0075] The principles and implementation manners of the present application are described by using specific examples in the specification. The above description of the embodiments is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method of uranium mining from sandstone uranium deposits, characterised in that, The application relates to a method for extracting uranium from a uranium ore bed. The interval between a pumping well and an injection well is determined according to the depth and permeability of the ore bed, and four perforation sections are determined according to the thickness of the ore bed; Each of the pumping well and the injection well corresponds to four perforation sections, and each perforation section corresponds to the direction of the surrounding well; when the perforation section on the pumping well is represented, the surrounding well is the injection well, and when the perforation section on the injection well is represented, the surrounding well is the pumping well; the interval between the pumping well and the injection well is 30-50 m when the depth of the pumping well and the injection well is 300-500 m, and the interval between the pumping well and the injection well is 35-60 m when the depth of the pumping well and the injection well is 500-800 m; The length of the perforation section is obtained, and the pumping well and the injection well are fractured from bottom to top according to the length of the perforation section, the fracturing range is controlled to be 5-10 m in radial length through the displacement and the amount of fracturing fluid, and the fracturing of the four perforation sections in the direction of any well is completed; The leaching agent is injected into the injection well after the fracturing is completed, and the leaching liquid is extracted from the pumping well after the fracturing is completed; The leaching liquid is treated to obtain a uranium product.

2. The method for uranium mining of sandstone uranium deposit according to claim 1, characterized in that, The length of the perforation section is 0.3-1.0 m, and the interval between adjacent perforation sections is 0.3-1.0 m.

3. The method for uranium mining of sandstone uranium deposit according to claim 1, characterized in that, The fracturing of the pumping well and the injection well from bottom to top according to the length of the perforation section specifically comprises the following steps: According to the length of the perforation section, two packers with an upper and lower interval longer than the length of the perforation section are sleeved on the casing; the packers are connected with fracturing facilities; The fracturing range is controlled through the displacement and the amount of fracturing fluid; Based on the fracturing range, the fracturing of the pumping well and the injection well from bottom to top is carried out by using the packers.

4. The method for uranium mining of sandstone uranium deposit according to claim 1, characterized in that, After the length of the perforation section is obtained, the pumping well and the injection well are fractured from bottom to top according to the length of the perforation section, and the fracturing of the four perforation sections in the direction of any well is completed, the method further comprises the following steps: The injection amount of the injection well before fracturing, the pumping amount of the pumping well before fracturing, the injection amount of the injection well after fracturing and the pumping amount of the pumping well after fracturing are obtained; The injection amount of the injection well before fracturing is compared with the injection amount of the injection well after fracturing to obtain an injection comparison result; The pumping amount of the pumping well before fracturing is compared with the pumping amount of the pumping well after fracturing to obtain a pumping comparison result; The permeability enhancement effect after fracturing is evaluated according to the injection comparison result and the pumping comparison result; If the permeability enhancement effect is within a set permeability enhancement range, the leaching agent is injected into the injection well after fracturing, and the leaching liquid is extracted from the pumping well after fracturing; If the permeability enhancement effect is not within the set permeability enhancement range, the length of the perforation section is adjusted, and the fracturing is carried out again.

5. The method for uranium mining of sandstone uranium deposit according to claim 1, characterized in that, The treatment of the leaching liquid to obtain a uranium product specifically comprises the following steps: The ion exchange adsorption resin is used to adsorb the leaching liquid to generate saturated resin and adsorption tail liquid; The saturated resin is eluted by using an eluent to obtain a qualified liquid containing uranium; The qualified liquid containing uranium is precipitated to obtain a uranium product.

6. The method for uranium mining of sandstone uranium deposit according to claim 5, characterized in that, The method further comprises: The leaching agent is added into the adsorption tail liquid, and the adsorption tail liquid is injected into the ore bed through the injection well after the fracturing is completed.

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