Systems and methods for lixiviant injection and electrokinetic sequences for in-SITU mining

Abstract

A method for operating a system for in-situ mining in a rock formation in an area of interest includes: receiving a lixiviant at a first well extending downward, injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material, and applying an electric field to at least one of the lixiviant or the solution by the first well as a first electrode and a second well as a second electrode, receiving the solution via the second well extending downward, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

Description

SYSTEMS AND METHODS FOR LIXIVIANT INJECTION AND ELECTROKINETIC SEQUENCES FOR IN-SITU MININGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Applications No. 63 / 678,617, filed on August 2, 2024, No. 63 / 678,656, filed on August 2, 2024, No. 63 / 678,640, filed on August 2, 2024, and No. 63 / 678,647, August 2, 2024, the entire disclosure of each of which is incorporated herein for all purposes.TECHNICAL FIELD

[0002] This disclosure generally relates to systems and methods for lixiviant injection and electrokinetic sequences for in-situ mining.BACKGROUND

[0003] Modem mining techniques can be generally categorized into three types: open pits (“surface mining”), underground mining, and in-situ mining. Over time, there are less materials available close to the surface, making surface mining less useful for reaching desirable materials, such as metals, including, but not limited to, copper, lithium, gold, uranium, rare earth elements (REE), etc. Long-term sustainability is also an issue with open pit and underground mining. For example, there is a large impact on soil, water, and air quality. Also, there are concerns about safety, such as a dam bursting, earth moving, or holes in the ground causing problems when using open pit and traditional underground mining. In contrast, in-situ mining, also known as in-situ leaching, in-situ recovery, solution mining, etc., is scalable to smaller or larger deposits of target materials, requires lower capital and operation cost than open pits or underground mining that requires large equipment, has a smaller overall environmental impact than the other mining techniques, and is safer than the other mining techniques.SUMMARY

[0004] This disclosure pertains to systems and methods for lixiviant injection and electrokinetic sequences for in-situ mining.

[0005] In-Situ mining traditionally relies on a lixiviant circulating through the ore body from injector wells to producer wells to leach metals. Use of an electric field has been proposed to assistthat process - in particular, in hard, low permeability rock. One issue is that the lixiviant is typically highly electrically conductive; its injection into the rock results in a lower overall electric resistivity of the rock mass, especially once the space is filled with lixiviant, which therefore results in an increase of the amount of electric power - and cost - needed to generate the electric field. To address that issue, some example embodiments of the present disclosure provide timing sequences including periods of lixiviant injections alternating with periods of electric current injection through the rock. Example embodiments also include timing sequences in which no lixiviant is injected, e.g., with only variations in the electric field over time; timing sequences in which no electric field is applied, e.g., with only variations in the composition and / or flow rate of the injected lixiviant over time; timing sequences in which the lixiviant injection is constant while the electric field is varied over time; and timing sequences in which the electric field is constant while the composition and / or flow rate of the injected lixiviant is varied overtime; and various combinations of any of the above. Furthermore, some example embodiments of the present disclosure measure several physical properties affected by those sequences to monitor the in-situ mining process, and then optimize the process using the measured properties.

[0006] This disclosure also pertains to systems and methods for electrokinetic in-situ mining.

[0007] Systems and methods for electrokinetic in-situ mining according to example embodiments may apply any of alternating current (AC), direct current (DC), and / or combination currents to create electric fields to apply an electrokinetic force to a lixiviant and / or pregnant lixiviant solution.

[0008] This disclosure also pertains to systems and methods for self-diverting lixiviant and formation modification for in-situ mining.

[0009] In example embodiments of the present disclosure, methods and systems apply acid diversion materials to in-situ mining to either modify the formation before extracting a target material or to improve the action of the lixiviant on the rock formation. In example embodiments of the present disclosure, methods and systems force the lixiviant into smaller fractures and passages, for example, rather than taking an easier path between the injection and production wells.

[0010] This disclosure also pertains to systems and methods for formation modification to mitigate conductive channels for electrokinetic in-situ mining.

[0011] In embodiments of the present disclosure, methods and systems reduce the short-circuiting of electrokinetic in-situ mining currents in both natural and artificially-induced larger fractures. In example embodiments, large fractures are selectively occupied by non-conductive or lower conductivity materials to force the electrical current into the desired parts of the formation.

[0012] A first aspect of this disclosure pertains to a method for operating a system for in-situ mining in a rock formation in an area of interest, the method including: receiving a lixiviant from a lixiviant source at a first well extending downward from a ground surface in the area of interest, performing at least one of injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material, or applying an electric field to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode, receiving the solution via the second well extending downward from the ground surface in the area of interest, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

[0013] A second aspect of this disclosure pertains to the method of the first aspect, wherein the timing sequence includes alternating durations of injection of the lixiviant with durations of application of the electric field.

[0014] A third aspect of this disclosure pertains to the method of any of the first or second aspects, wherein a first duration of injection of the lixiviant is not overlapping with a first duration of application of the electric field.

[0015] A fourth aspect of this disclosure pertains to the method of any of the first to third aspects, wherein a third duration of injection of the lixiviant overlaps with a fourth duration of application of the electric field.

[0016] A fifth aspect of this disclosure pertains to the method of any of the first to fourth aspects, wherein at least two durations of application of the electric field last for different amounts of time.

[0017] A sixth aspect of this disclosure pertains to the method of any of the first to fifth aspects, wherein at least two durations of injection of the lixiviant last for different amounts of time.

[0018] A seventh aspect of this disclosure pertains to the method of any of the first to sixth aspects, wherein a composition of the lixiviant is different between at least two durations of injection of the lixiviant.

[0019] An eighth aspect of this disclosure pertains to the method of any of the first to seventh aspects, wherein a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

[0020] A ninth aspect of this disclosure pertains to the method of any of the first to eighth aspects, wherein a strength of the electric field is different between at least two durations of application of the electric field.

[0021] A tenth aspect of this disclosure pertains to the method of any of the first to ninth aspects, wherein a type of the electric field is different between at least two durations of application of the electric field.

[0022] An eleventh aspect of this disclosure pertains to the method of any of the first to tenth aspects, wherein at least one of the composition of the lixiviant, the flow rate of the lixiviant, the timing of injection of the lixiviant, the strength of the electric field, the type of the electric field, or the timing of the application of the electric field is different between at least two durations of the injection of the lixiviant or the application of the electric field based on performing a measurement performed over time or at a predetermined point in time.

[0023] A twelfth aspect of this disclosure pertains to the method of the eleventh aspect, wherein the performing the measurement includes: measuring a voltage and a current in the first and second wells, and determining resistivity of the rock formation based on the measured voltage and current.

[0024] A thirteenth aspect of this disclosure pertains to the method of the eleventh aspect, wherein the performing the measurement includes: measuring pressure in the first and second wells, and based on the measured pressure, performing at least one of: identifying at least one flow regime, or determining at least one characteristic of the rock formation.

[0025] A fourteenth aspect of this disclosure pertains to the method of the eleventh aspect, wherein the performing the measurement includes: measuring temperature and pH values in the first and second wells, and based on the measured temperature and pH values, determining at least one of: a flow of the lixiviant in the rock formation, or effectiveness of an electrokinetic process caused by the application of the electric field.

[0026] A fifteenth aspect of this disclosure pertains to the method of the eleventh aspect, wherein the performing the measurement includes: measuring at least one of a composition of the lixiviant or a property related to the composition of the lixiviant in the first well and at least one of a composition of the solution or a property related to the composition of the solution in the second well, and based on the measurements, determine at least one of: a penetration of the lixiviant into the ore, an actual kinetic parameter of the metal leaching process, existence of at least one of a flow highway or a flow barrier in the rock formation, clogging of part of a rock pore system in the rock formation, or potential damage to the first well, the second well, or another part of the system.

[0027] A sixteenth aspect of this disclosure pertains to the method of any of the first to fifteenth aspects, and further includes: sectioning the area of interest into a plurality of zones, and independently operating each zone according to a respective timing sequence.

[0028] A seventeenth aspect of this disclosure pertains to the method of the sixteenth aspect, and further includes: measuring each zone independently.

[0029] An eighteenth aspect of this disclosure pertains to a system for in-situ mining of a rock formation in an area of interest, including: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant from a lixiviant source, performing at least one of: injecting the lixiviant into a permeable layer of the rock formation to dissolve a target material to form a solution containing the lixiviant and the target material, or operating as a first electrode to apply an electric field to at least one of the lixiviant or the solution, and a second well extending downward from the ground surface in the area of interest, the second well configured to: when the first well is operating as a first electrode, operate as a second electrode to apply the electric field to at least one of the lixiviant or the solution, receive the solution, and pump the solution to a processing plant to separate the target material from the lixiviant, whereinone or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

[0030] A nineteenth aspect of this disclosure pertains to the system of the eighteenth aspect, wherein the timing sequence includes alternating durations of injection of the lixiviant with durations of application of the electric field.

[0031] A twentieth aspect of this disclosure pertains to the system of any of the eighteenth or nineteenth aspects, wherein the timing sequence includes at least one of: a first duration of injection of the lixiviant not overlapping with a first duration of application of the electric field, or a third duration of injection of the lixiviant overlapping with a fourth duration of application of the electric field.

[0032] A twenty-first aspect of this disclosure pertains to the system of any of the eighteenth to twentieth aspects, wherein at least two durations of application of the electric field last for different amounts of time.

[0033] A twenty-second aspect of this disclosure pertains to the system of any of the eighteenth to twenty-first aspects, wherein at least two durations of injection of the lixiviant last for different amounts of time.

[0034] A twenty-third aspect of this disclosure pertains to the system of any of the eighteenth to twenty-second aspects, wherein at least one of a composition or a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

[0035] A twenty-fourth aspect of this disclosure pertains to the system of any of the eighteenth to twenty-third aspects, wherein at least one of a strength and a type of the electric field is different between at least two durations of application of the electric field.

[0036] A twenty -fifth aspect of this disclosure pertains to the system of any of the eighteenth to twenty-fourth aspects, wherein: the area of interest is sectioned into a plurality of zones, and each zone is independently operable according to a respective timing sequence.

[0037] A twenty-sixth aspect of this disclosure pertains to the system of the twenty -fifth aspect, wherein a composition of the lixiviant is provided on a zone-by-zone basis.

[0038] A twenty-seventh aspect of this disclosure pertains to the system of any of the eighteenth to twenty-sixth aspects, wherein: the first well includes an injection well, and the second well includes a production well.

[0039] A twenty-eighth aspect of this disclosure pertains to the system of any of the eighteenth to twenty-seventh aspects, wherein: one of the first electrode and the second electrode includes an anode, and the other of the first electrode and the second electrode includes a cathode.

[0040] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0041] Additional features and advantages of embodiments of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such embodiments. The features and advantages of such embodiments may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims or may be learned by the practice of such embodiments as set forth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0042] To describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific implementations thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example implementations, the implementations will be described and explained with additional specificity and detail through the use of the accompanying drawings.

[0043] FIG. 1 is a cross-sectional diagram of an in-situ mining operation according to a related art.

[0044] FIG. 2 is a diagram of electrokinetic in-situ leaching (EK-ISL) for an in-situ mining operation according to a related art.

[0045] FIG. 3 is a timing diagram for an in-situ mining operation in accordance with an example embodiment of the present disclosure.

[0046] FIG. 4 is a timing diagram for an in-situ mining operation in accordance with an example embodiment of the present disclosure.

[0047] FIG. 5 is a diagram of EK-ISL for an in-situ mining operation in accordance with an example embodiment of the present disclosure.

[0048] FIG. 6 is a graph of a DC waveform in accordance with an example embodiment of the present disclosure.

[0049] FIG. 7 is a graph of an AC waveform in accordance with an example embodiment of the present disclosure.

[0050] FIG. 8 is a graph of a time-varying DC waveform in accordance with an example embodiment of the present disclosure.

[0051] FIG. 9 is a flowchart for a method in accordance with an example embodiment of the present disclosure.

[0052] FIG. 10 is a flowchart for a method in accordance with an example embodiment of the present disclosure.

[0053] FIG. 11 is a flowchart for a method in accordance with an example embodiment of the present disclosure.

[0054] FIG. 12 is a diagram of a rock formation according to a related art.

[0055] FIG. 13 is a diagram of a rock formation in accordance with an example embodiment of the present disclosure.

[0056] FIG. 14 illustrates certain components that may be included within a computer system according to an example embodiment of the present disclosure.

[0057] Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of the configuration and arrangement of components set forth in the following description or illustrated in the accompanying drawings. The disclosure is capable of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings.DETAILED DESCRIPTION

[0058] While the subject disclosure applies to embodiments in many different forms, there are shown in the drawings and will be described in detail herein specific embodiments with the understanding that the present disclosure is an example of the principles of the invention. It is not intended to limit the invention to the specific illustrated embodiments. The features of the invention disclosed herein in the description, drawings, and claims can be significant, both individually and in any desired combination for the operation of the invention in its various embodiments. Features from one embodiment can be used in other embodiments of the invention. In the description of the drawings like reference numerals refer to like elements.

[0059] In-Situ mining traditionally includes providing a series of wells, including injectors (or “injection wells”), producers (or “production wells”), and control wells (or “monitor wells”). It relies on the right lixiviant reaching the ores and freeing the metal to enrich the solution being circulated from the injection to the production well. The extraction of target minerals or materials by this technique requires that the target be soluble, e.g., potash, potassium chloride, sodium chloride, sodium sulfate, which dissolve in water. Some minerals, such as copper minerals, lithium, and uranium oxide, require a liquid medium as a lixiviant, such as acid or carbonate solutions, or a brine, to dissolve. Gold, for example, may use cyanide, chlorine, bromine, or iodine as a lixiviant.An oxidant, such as oxygen and / or hydrogen peroxide mixed with sodium carbonate or carbon dioxide, may be used as a lixiviant for uranium. Lixiviant may also be, for example, gases, various chemicals, and / or other materials that can be injected into the formation in accordance with example embodiments. For instance, oxygen and / or bacteria may be injected as lixiviants. In an example embodiment, chemicals may be injected in the final phase of in situ leaching to bring the pH of the formation close to its original value. A lixiviant chemical may be injected in the formation, e.g., a lixiviant-leaching agent, a chemical provided to “prepare” the formation, or a chemical provided to clean the formation afterward. As such, the term “lixiviant” is used herein to broadly describe materials that are injected into the rock formation, and then removed from the rock formation, during an in-situ mining operation.

[0060] The lixiviant is injected into the target mineral via one or more injector wells. The target mineral is dissolved by the lixiviant and the lixiviant mixed with the target mineral, which may be referred to as a “pregnant lixiviant” or “pregnant solution” is pumped via one or more producer wells to the surface. The pregnant lixiviant is then processed to separate the target mineral from the lixiviant to recover the target mineral. Different patterns of injection and production wells can be used. Control wells are usually drilled around those wells to ensure that groundwater is not contaminated.

[0061] FIG. 1 is a cross-sectional diagram of an in-situ mining operation according to a related art.

[0062] FIG. 1 shows a mining area 100 in which control wells 105, 110, 115 are on a periphery of the mining area 100 to monitor for groundwater contamination. The control wells 105, 110, 115 can pass through and / or end at any of the various layers of the ground, e g., a top layer 120, sands / clays / gravels 125, an upper clay layer 130, a target layer 135, and / or a lower clay layer 140. An injection well 145 pumps the lixiviant from a production plant (not shown) from the surface into the permeable target layer 135. A production well 150 pumps the pregnant lixiviant solution containing the target material from the target layer 135 back to the production plant on the surface.

[0063] FIG. 2 is a diagram of electrokinetic in-situ leaching (EK-ISL) for an in-situ mining operation according to a related art.

[0064] Electrokinetic in-situ leaching (EK-ISL) may be used to assist the in-situ mining process. A description of EK-ISL is made by Evelien Martens et al., “Toward a more sustainable mining future with electrokinetic in situ leaching,” Science Advances, 7, eabf9971 (2021), DOI: 10.1126 / sciadv.abf9971, pp. 1-10 (https: / / www.science.org / doi / 10.1126 / sciadv.abf9971). FIG. 2, which was published in the above reference, provides a 3D isometric view of an industrialscale EK-ISL operation in Part (a), including potential electrode configuration, above-ground energy source, lixiviant supply and recovery reservoirs connected to vertical wells, and metal recovery treatment facility. Part (b) shows a cross-sectional view of the ore interface between an anode well and a cathode well. Part (c) illustrates principal hydrogeochemical reactions between the lixiviant and the ore material when subjected to EK-driven electromigration.

[0065] When using EK-ISL, an electric field is created between one well (or “borehole”) acting as an anode and one well acting as a cathode. This is generally performed by applying a low- voltage DC current. EK-ISL is combined with the injection of lixiviant to help the lixiviant reach the metal and / or metal-rich minerals in the rocks, then EK-ISL controls the transport of the pregnant solution to the production well.

[0066] - Lixiviant injection and electrokinetic sequences for in-situ mining

[0067] Of note, electrokinetic use to assist in-situ mining of metal in hard rocks is relatively new, but it has been used for years in other fields (soil remediation, retention pond cleaning). In some of those field of remediation, positive results have been reported with pulsed DC current. Table 1 below shows a summary of effects of pulsed electric field application in electrokinetic and electrodialytic soil remediation from Sun, Tian Ran, “Effect of pulse current on energy consumption and removal of heavy metals during electrodialytic soil remediation,” Technical University of Denmark, 2013. However, continuous application of a pulsed DC current electric field can be expensive when used for an entire mining operation duration.[Table 1]

[0068] Accordingly, there is a need for systems and methods for combining lixiviant injection and / or electrokinetic sequences for in-situ mining.

[0069] I. Applying Combined Timing Sequences of Lixiviant Injection and Electric Current

[0070] Most metal ores can be found in hard, often fractured rocks. The hydraulic permeability and resistivity of the rock at the scale used for in-situ leaching of metals depends on the intrinsic permeability of the rock, the in-situ stresses, and also the characteristics of the fracture network, e.g., fracture spacing, aperture, and connectivity.

[0071] Understanding the spatial distribution of subsurface permeability, which is the capacity of rocks to transmit fluids, is crucial for the effective management of geothermal, oil and gas, and groundwater resources. However, permeability can vary significantly across different locations and may not always be accurately mapped using conventional industry tools like seismic reflection. Permeability can also change over time. For instance, the pore system can get clogged because of mineral deposit, which may result in permeability loss. As another example, fractures can be extended, which may result in an increase in permeability. Various measurements performed with respect to time may allow for detection of those changes. As such, the timing sequences described herein may address those changes, and may monitor the effect of actions taken to address those changes. Measuring the electrical resistivity of rocks could be beneficial in assessing permeability when there is an established correlation between these two properties. Both resistivity and permeability are heavily influenced by the fracture density within the rock and the extent to which these fractures are open. There exists a pivotal fracture width, beyond which there can be observed a marked increase in both permeability and resistivity, contingent upon the degree of connectivity within the fracture networks.

[0072] When injecting fluid, e.g., a lixiviant, into the fractured rock formation, the fractures become the preferred pathways for the fluid, for example, due to lesser hydraulic resistance. The individual fracture apertures - and the fracture network connectivity - are also affected. Lixiviants are typically electrolyte-rich solutions, which can cause a decrease of the fracture and fractured rock electric resistivity as they fill the fracture cavities.

[0073] When applying electrokinetic in-situ leaching (EK-ISL), a fixed low voltage electric field is usually created. The electric power needed to do that is inversely proportional to the overall resistivity of the fractured rock at the scale of the in-situ mining operation, e.g., W = I2 / R, where W is power, I is current, and R is resistivity. Electric power needed directly translates into operationcost, and is therefore a very important parameter from an operation point of view, e.g., in determining the economic viability of EK-ISL.

[0074] Example embodiments of the present disclosure create sequences in which lixiviant is injected for a given period of time, e.g., to reach the fractures next to the metal rich minerals, with no applied electric field, then the injection of lixiviant is stopped and an electric current is applied / injected to create an electrokinetic effect throughout the rock. As such, less electric current - and therefore overall power - will be needed to generate an electric field characterized by the same voltage.

[0075] FIG. 3 is a timing diagram for an in-situ mining operation in accordance with an example embodiment of the present disclosure.

[0076] An example timing sequence 300 with one level of lixiviant flowrate (e.g., simply turning on / off at a single flow rate) and one level of voltage for the electric field (e.g., simply turning on / off at a single voltage level) is shown in FIG. 3. An example timing of the application of an induced electric field is shown in FIG. 3, part (a). An example timing of injection of a lixiviant is shown in FIG. 3, part (b). Both part (a) and part (b) in FIG. 3 function over the same time scale and period. In the nonlimiting example of FIG. 3, a lixiviant may be injected into the target layer, e.g., target layer 135 of FIG. 1, from a start time to to a first time ti for a first duration 310, then the lixiviant may be stopped and an electric field may be applied until a second time t2 for a second duration 320. The injection of the lixiviant and the application of the electric field may be alternated as desired over time, e.g., at times t3, t4, ts, etc. for additional durations 330, 340, 350, etc. while the wells are in operation. It should be appreciated that the timings illustrated in FIG. 3 are shown for convenience of explanation, and the number and duration of each of the lixiviant injections and electric field application are not limited thereto. It should be appreciated that the times to to tj may or may not be at evenly-spaced intervals. The times ti to Is and the time of each duration start and end may be selected, e.g., by the operator, for example, to optimize production and account for various operational constraints. The time periods may be determined based on monitored parameters of the mining operation, for example, stresses on the rock formation or a distribution of the stresses on the rock formation. The duration of each injection / application mayalso be determined and / or adjusted based on a measured output, e.g., to account for changes in the concentration of pregnant lixiviant received from the production well(s).

[0077] FIG. 4 is a timing diagram for an in-situ mining operation in accordance with an example embodiment of the present disclosure.

[0078] Multiple variations of the basic timing sequence 300 can be devised in accordance with example embodiments of the present disclosure. An example timing of the application of an induced electric field is shown in FIG. 4, part (a). An example timing of injection of a lixiviant is shown in FIG. 4, part (b). Both part (a) and part (b) in FIG. 4 function over the same time scale and period. In the nonlimiting, more complex, example of FIG. 4, the lixiviant injection flow rate and the current injection level can vary with time. Also, the application of lixiviant and electric field may overlap, e.g., at a given time, lixiviant may be injected while an electric field is applied concurrently. For example, with reference to FIG. 4, a lixiviant having a first solution, may be injected into the target layer, e.g., target layer 135 of FIG. 1, from a start time to to a first time ti for a first duration 410. The first solution (e.g., Solution 1) may have a first concentration of lixiviant, may be at a first flow rate, and / or may have another property for that solution. Then, the injection of the first solution may stop and the lixiviant may be injected for a second duration 440 using a second solution, e.g., Solution 2, which may have different properties from the first solution, e.g., Solution 1. While the lixiviant is still being injected, a direct current (DC) electric field may start to be applied at a second time t2 for a third duration 430. Then the second solution lixiviant may be stopped at a third time t3 at the end of the second duration 420 while the DC electric field is still being applied. Also, while the DC electric field is still being applied in the third duration 430, the lixiviant may begin to be injected again, e.g., using the first solution, at a fourth time t4 at the beginning of the fourth duration 440.

[0079] In the example illustrated in FIG. 4, at a fifth time ts before the end of the fourth duration 440, while the lixiviant is still being injected, the application of the DC field may be stopped at the end of the third duration 430. Then, at a sixth time te before the end of the fourth duration 440, while the lixiviant is still being injected, an alternating current (AC) electric field may begin to be applied for a fifth duration 450. The injection of the lixiviant may then be stopped at a seventh time t? at the end of the fourth duration 440. At an eighth time ts, the AC electric fieldmay be stopped and lixiviant may be injected for a sixth duration 460, for example, using a third solution, e.g., Solution 3, which may have different properties from the first and second solutions, e.g., Solution 1 and Solution 2. Then, at a ninth time t9, while the lixiviant is being injected, a DC electric field may be applied for a seventh duration 470 until a tenth time tio- Finally, the injection of lixiviant may be stopped at the end of the sixth duration 460 at an eleventh time tn.

[0080] The times ti to tn and the time of each duration start and end may be selected, e.g., by the operator, for example, to optimize production and account for various operational constraints. The time periods may be determined based on monitored parameters of the mining operation, for example, stresses on the rock formation or a distribution of the stresses on the rock formation. The duration of each injection / application may also be determined and / or adjusted based on a measured output, e.g., to account for changes in the concentration of pregnant lixiviant received from the production well(s). It should be appreciated that the particular overlappings, solutions, and / or electric field types and / or strengths shown in FIG. 4 are provided as an illustrative example, and embodiments according to the present disclosure include any examples that vary the timing and / or type of lixiviant and / or electric field in which either or both of the lixiviant or electric field are applied for multiple durations that are each less than the total operational time for the well such that at least one of the lixiviant and electric field is in an off-state for part of the operational time of the well.

[0081] In the illustrated example, the electric field applied for durations 430 and 470 is a DC electric field, and the electric field applied for duration 450 is an AC electric field, but embodiments are not limited thereto. For example, any combination of DC and AC fields may be applied in example embodiments, including fields of all one type or repeating fields of either type. While DC current is more commonly used to create the electric field, AC current can also be used for given periods in sequences in accordance with example embodiments of the present disclosure.

[0082] In the illustrated example, three solutions, e.g., Solution 1, Solution 2, and Solution 3 are shown, but embodiments include as many or as few solutions for the lixiviant as desired. The choices of electric field strength and type and the choices of lixiviant type, concentration, etc. may be optimized by testing, prior knowledge of the conditions of the rock formation, or by expected outcomes of the application of the selected lixiviant and / or electric field to the rock formation. Asanother example, embodiments may vary the rate of injection of lixiviant over time, with no electric field created and no electrokinetic effect created to assist in-situ mining. In such an example, the lixiviant injection may occur over the entire operational time period, or may start and stop, for example, to vary stresses on the rock formation. In yet another example, the concentration of the lixiviant may be changed over time, which may be applied with or without the application of an electric field or electrokinetic effect.

[0083] The timing sequences according to example embodiments may be applied where there are multiple injection and production wells and / or where there are multiple anodes and cathodes. The timing sequences may be applied across more than two wells, e.g., they may be applied among a field of injection and production wells in an area of interest. In addition, in example embodiments of the present disclosure, the injection scheme can involve multiple wells in an area of interest, with some injection wells and / or some production wells being given roles that may change over time. For example, some wells may be involved in the injection / production of lixiviant, while other wells may be given a role of applying an electric field. In another example, the assigned roles of the wells may change over, e.g., some injection / production wells may stop handling lixiviant and start applying an electric field while other wells may stop applying an electric field and start handling lixiviant. As another example, a pair of injection / production wells that are handling lixiviant may start and stop applying an electric field, or vice versa. Therefore, the application of lixiviant and electric field can vary over time over an area of interest in which multiple injection and production wells are arranged. The application of lixiviant and electric field may be turned on and off and may overlap or not overlap as desired for optimizing, improving, or increasing yield of the target resource from the rock formation or for optimizing, improving, or increasing cost efficiencies of the mining operation.

[0084] In another example embodiment, a composition of the lixiviant may vary over time. For example, as shown in FIG. 4, different solutions can be applied. As another example, the composition can change while the lixiviant is being injected, even without pausing the injection. In another example, the composition of the lixiviant may be different from one well to another, or from one zone of one well to others. In yet another example, other chemicals and / or materials can be injected together with - or instead of - the lixiviant.

[0085] II Measurement

[0086] In another example embodiment of the present disclosure, various measurements may be made with respect to time or at a certain point in time during the timing sequences described above. The measurements may include measuring the voltage and the intensity of the current, e.g., in the wells and / or in selected zones in the wells), which can be interpreted in terms of rock mass resistivity (e.g., R = V / I), varying as a result of lixiviant injection and metal leaching, among others. The measurements may also include measuring the pressures in the wells or zones in the wells. The pressures and the pressure derivatives computed therefrom can be used, for example, to identify flow regimes and / or determine characteristics near and farther from the well. Furthermore, the measurements may include measuring the temperature and the pH values, e.g., in the wells or in selected zones in the wells. The temperature and the pH values can be interpreted in relation to flow in the rock mass and / or in terms of effectiveness of the electrokinetic process. Moreover, the measurements may include measuring the composition (or a property related to the composition) of the lixiviant in the injector well and of the “pregnant lixiviant” in the producer wells. We can then interpret those measurements together or separately to determine the penetration of the lixiviant into the ore, the actual kinetic of the metal leaching process, the existence of flow highways and / or flow barriers in the rock mass, possible clogging of part of the rock pore system, potential damage to the well and production system, etc. It should be appreciated that the measurements given above are nonlimiting examples, and other measurements may be performed to gain information on the wells, the rock formation, the target resource, or any other parameter to help inform the setting of the control timing sequence(s) for the wells. As an example, measurements may be performed using a fiber optic tool.

[0087] The resistivity determined by measuring the voltage and current may be a resistivity value for the formation / rock mass as a whole (e.g., the rock, formation fluid, fractures, and lixiviant) and the resistivity may vary over time. As such, the resistivity may be determined with respect to time - with multiple measurements over time - and its changes may be interpreted in term of changes in the formation / rock mass. Also, the resistivity measurement / determination may be used to regulate a current level for an applied electric field, e.g., to maintain a constant voltage between the wells.

[0088] III. Improvement or Optimization

[0089] In another example embodiment of the present disclosure, the overall metal production system may be improved or optimized by leveraging the above measurements to: a) adjust the injection and electric field creation sequences described above; b) reduce or minimize the amount of lixiviant used and / or improve or optimize its composition and / or improve or optimize the amount of lixiviant that can be recycled; c) reduce or minimize the amount of electric power used; d) reduce or minimize damage to the anode / cathode wells; e) increase or maximize the ultimate (e.g., total) metal recovery percentage; f) accelerate the recovery of metals (e.g., same amount, but faster); g) improve or optimize the breakdown of metal recovered, e.g., ores are generally polymetallic, and many mines produce more than one metal. The same could be applied to other target resources as appropriate.

[0090] The improvement or optimization can be done, for example, by leveraging a parametrized model of the mining operation. For example, a physics-based model may represent the main elements of the mining system, and that model can be run with different parameters / configurations. The parameters can be adjusted or tweaked for the model to match the measurement done at a given site. The parametrized physics-based model can be run to optimize parameters values for the site. As another example, the improvement or optimization can leverage a data-based model, e.g., machine learning or artificial intelligence, that is not explicitly based on physics. Moreover, the improvement or optimization can be done by leveraging a combination of using the parametrized (or physics-based) model and using the data-based model.

[0091] - Electrokinetic in-situ mining

[0092] In the field of in-situ mining, holes (or wells) are commonly disposed with a relatively short spacing between them to improve the hydraulics and the reservoir contact. The relatively new technique of electrokinetic enhancement, e.g., EK-ISL, uses electrodes to drive current through the formation. This has multiple advantages. The first is the creation of bulk motion of the lixiviant independent of the hydraulic connectivity. The second is the ability to alter or bypass local electric fields around mineral particles, and thus improve the contact between the lixiviant and the desired metal. Third, the electrical field provides a lixiviant flow control that is electric field driven,not hydraulic driven. Finally, the current flow acts directly on the metal ions, driving them to the collection point.

[0093] While this technique may offer advantages over in-situ mining without EK-ISL, it also comes with challenges. The current and energy requirements can be significant, and can be adversely affected by well construction or formation characteristics. The fluid near the electrodes experiences a large change in pH due to the motion / accumulation of OH- and H+ ions near respective electrodes. Such change in pH can corrode the electrodes and any metal piping nearby, which can decrease their efficiency and shorten their lifespans, thus increasing operational costs and introducing delays for downtime for replacement of parts. Ion exchange membranes can localize this and offer some tools for control, but requires additional equipment and therefore cost.

[0094] Conventional EK-ISL applies direct current (DC) electric fields within the rock formation. DC current is simple and offers an advantage over in-situ mining without electrokinesis, e.g., bulk ion motion. However, this comes with polarization of the formation and large changes in pH near the electrodes.

[0095] There is a need to improve the application of electric fields for electrokinetic in-situ mining.

[0096] FIG. 5 is a diagram of EK-ISL for an in-situ mining operation accordance with an example embodiment of the present disclosure.

[0097] In a mining area 500 of FIG. 5, a metal-bearing rock formation 510 may have a first well 515 and a second well 520 with respective well bores 525 and 530 drilled into the rock formation 510, e.g., to a target layer such as target layer 135 of FIG. 1. Electrodes 535 and 540 may be disposed in the wells 515 and 520. A power supply 545 may produce a potential difference, i.e., voltage, between the electrodes 535 and 540, leading to a current flow through a treatment volume 550 within the rock formation 510. Lixiviant may be pumped from a first tank 555 with a first pump 560 into the first well 515. While a specific polarity is illustrated as being applied by the power supply 545, in the FIG. 5 example, an appropriate polarity to be applied will depend, for example, on the metal, the formation, and the lixiviant. The pregnant lixiviant may then be removed from the second well 520 by a second pump 565 and stored in a second tank 570.

[0098] FIG. 6 is a graph of a DC waveform in accordance with an example embodiment of the present disclosure.

[0099] FIG. 6 shows a direct current (DC) waveform 600 according to an example embodiment, with a voltage Vi showing no variation on the time axis. In other words, the application of the waveform 600 is time-invariant. The DC waveform 600 can be applied by the power supply 545 to the electrodes 535 and 540 of FIG. 5.

[0100] FIG. 7 is a graph of an AC waveform in accordance with an example embodiment of the present disclosure.

[0101] FIG. 7 shows an alternating current (AC) waveform 700, according to an example embodiment, having a period of time at a positive voltage Vi and a second period of time at a negative voltage V2. A period 710 is a time period over which the waveform 700 repeats. As an AC waveform, the integral of the waveform over the period 710 is zero.

[0102] Alternating current (AC), also referred to herein as “AC current,” may be characterized by a substantially balanced positive and negative phase in the time domain. AC current should be able to exploit one of the important aspects of electrokinetic in-situ mining, e.g., altering local electric fields to allow better lixiviant access to metals on ore particles. Two time constants are important: local polarization time and formation penetration time. The conductivity and ionic characteristics of the formation mean that an applied voltage takes time to reach a given location in the rock formation. Thus, there are upper limits to the frequencies that are applicable to electrokinetic in-situ mining. While remaining substantially balanced, these waveforms may include substantially different voltages and currents in their positive and negative periods. Time-varying application can range, for example, from 400 Hertz to days per cycle.

[0103] The application of an AC waveform can mitigate some problems caused by DC current electric fields. For example, application of a DC electric field can cause the lixiviant fluid near the electrodes to experience a large change in pH due to the motion / accumulation of OH- and H+ ions, respectively, at the cathode electrode and the anode electrode. As discussed above, this can cause corrosion in the electrodes and any metal piping nearby, which can result in costly damage to the mining operation. In contrast, application of an AC electric field reduces, minimizes, or avoidssuch concentration of OH- and H+ ions without requiring additional membranes or mitigation equipment. Furthermore, when the target material is a metal ore, has a natural charge, or has a charge induced by the injection of the lixiviant, e.g., by electrostatic forces between the ore and the lixiviant, DC current can operate in only one direction based on which side of the particles of the target material has a positive or negative charge. In contrast, AC current can affect both sides of the charged particles, which may provide more effective control of the flow of the particles. In one example, the AC current can alternately push and pull the particles, e.g., to vibrate or wiggle the particles out of spaces in the permeable layer of the rock formation, e.g., the target layer 135 of FIG. 1.

[0104] FIG. 8 is a graph of a time-varying DC waveform in accordance with an example embodiment of the present disclosure.

[0105] FIG. 8 shows a time-varying DC waveform 800 according to an example embodiment. The waveform 800 applies a voltage Vi, which is a higher voltage than a second voltage V2. The waveform 800 holds the higher voltage Vi for a shorter period of time than the second voltage V2. The waveform repeats over period 810. While the second voltage V2 is shown as being positive in the example of FIG. 8, alternatively, the second voltage V2 can be negative, so long as an integral of the waveform over the time period 810 is non-zero.

[0106] As used herein, “time-varying DC current” means that the integral of the voltage or current waveform has either a positive or negative value. Useful time-varying DC waveforms include a baseline DC current with pulsations or waves superimposed on this baseline. These allow separate control of the overall formation polarization, while still allowing periods of intense local particle polarization for lixiviant access.

[0107] It should also be appreciated that example embodiments may include switching among applying the time-invariant DC waveform, the AC waveform, and the time-varying DC waveform over time during operation of an in-situ mine. The timing of the switching may be determined according to a predetermined sequence or may be determined based on pre-testing or testing during operation of the mine.

[0108] - Self-diverting lixiviant and formation modification for in-situ mining

[0109] When lixiviant is injected in a well, it will tend to travel into small spaces wherever the liquid can fit. This can cause undesirable short circuits in an EK-ISL operation when the spaces in the fractures are filled and resistivity of the fracture decreases. Moreover, a large amount of lixiviant and pressure is needed to push into small fractures and increase the size of the small fractures to get to the target material inside. There is thus a need to control where and how lixiviant travels within fractures in in-situ mining.

[0110] Example embodiments include methods and systems for application of self-diverting lixiviant to in-situ mining. For example, an acid diverter system may be used as a self-diverting lixiviant. Acid diverter systems may be applicable to both rock formation alteration / treatment and to the application of lixiviant. While two examples of self-diverting lixiviant are shown, embodiments of the present disclosure relate to the general technique of applying selective diversion of lixiviant to the field of in-situ mining.

[0111] In a related art of an oilfield, acid is often applied to improve reservoir connection by selectively etching the rock formation. However, there is a strong tendency for the acid stream to only act on the larger fractures - the fractures being either natural or induced. This leads to relatively little improvement for a high effort. However, materials such as a viscoelastic diverting acid (VDA) are available to cause the acid stream to selectively attack the smaller fractures and passages instead of taking the easy paths into larger passages. VDA maintains a thin consistency while being pumped into a well and initially injected into a rock formation by injection wells. Upon acid spending, the fluid rapidly develops viscosity in place and becomes self-diverting. The viscosity buildup serves as a barrier to reduce the flow rate of the VDA into larger fractures and allow remaining fluid to move into untreated areas. VDA exploits the reaction with the formation carbonates to transform from a low viscosity state to a high viscosity state. VDA can be diluted to become liquid again so that the pregnant lixiviant can be pumped out by production wells.

[0112] Although VDA is a carbonate-specific example, the general technique is applicable elsewhere, e g., without the presence of carbonate. While VDA is an example material that can be applied according to example embodiments, other materials may also be used. For example, materials that can be emulsified may be used as self-diverting lixiviants according to anembodiment. As another example, any acid that can be emulsified may be used as a self-diverting lixiviant in accordance with an embodiment of the present disclosure. Ferric chloride and hydrochloric acid are also examples of lixiviants that can be emulsified and used as self-diverting acid lixiviants. The acid-internal emulsion enhances viscosity, which assists in diverting the flow during matrix treatments, and may help prevent leakoff that is monitored by the control wells. Lixiviants used in in-situ mining are commonly acidic liquids, so the use of self-diverting acid represents a significant improvement in formation contact abilities. However, in example embodiments, any lixiviant material that can be initially applied as a liquid that increases viscosity in place (or “in-situ”) to become self-diverting may be considered appropriate for example embodiments of the present disclosure.

[0113] FIG. 9 is a flowchart for a method in accordance with an example embodiment of the present disclosure. FIG. 10 is a flowchart for a method in accordance with an example embodiment of the present disclosure. FIG. 11 is a flowchart for a method in accordance with an example embodiment of the present disclosure.

[0114] FIG. 9 shows a method 900 for in-situ mining in a rock formation in an area of interest, e.g., in the mining area 100 of FIG. 1. In operation 910, the method 900 may include receiving a lixiviant in fluid form from a lixiviant source at a first well extending downward from a ground surface in the area of interest. Next, in operation 920, the method 900 may include injecting the lixiviant into the rock formation via the first well to dissolve the target material to form a solution containing the lixiviant and the target material. The method 900 may allow the lixiviant to increase in viscosity such that the lixiviant self-diverts from larger fractures in the rock formation into smaller fractures in the rock formation to dissolve the target material in the smaller fractures to form the solution (operation 930). Then, the method 900 may include, in operation 940, receiving the solution via a second well extending downward from the ground surface in the area of interest. In operation 950, the method 900 may include pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant.

[0115] Certain additional example embodiments are shown in FIG. 10, which starts with and includes the method 900 of FIG. 9. In one example, the method 1000 may include: converting remaining increased-viscosity lixiviant into a lower-viscosity form (operation 1010), receiving theconverted lixiviant via the second well (operation 1020), and pumping the converted lixiviant out of the rock formation via the second well (operation 1030). In another example, the method 1000 may include: sectioning the area of interest into a plurality of zones (operation 1040), and providing a respective composition of the lixiviant on a zone-by-zone basis (operation 1050).

[0116] Certain additional example embodiments are shown in FIG. 11, which starts with and includes the method 900 of FIG. 9. An example method 1100 may include: applying electrokinetic in-situ leaching (EK-ISL) to the first well and the second well (operation 1110). In one example, one of the first well and the second well operates as an anode, and the other of the first well and the second well operates as a cathode, or vice versa. The operation of the first and second wells as anode and cathode may be switched at any time during the mining operation according to example embodiments. Another example of the method 1100 may include: operating the first well as an injection well (operation 1120), and operating the second well as a production well (operation 1130). Another example of the method 1100 may include: arranging a plurality of control wells at a periphery of the area of interest (operation 1140), and monitoring groundwater in the area of interest via the control wells (operation 1150). These operations as injection and production wells may also be switched at any time during the mining operation according to example embodiments.

[0117] - Formation modification to mitigate conductive channels for electrokinetic in-situ mining

[0118] Short-circuiting, by both natural factures in the rock formation and fractures in the rock formation that are artificially-induced, of electrokinetic in-situ mining currents may occur in larger fractures. Solid materials, such as sand or ceramic materials, carried in fluids may be pumped into natural fractures when lixiviant is injected into the rock fractures. Such pumping may create pressures inside the fractures that are below a fracture threshold of the formation, or the pressures may be above the fracture threshold, which may result in additional fractures being created in the rock formation, i.e., the additional fractures are artificially induced. In either case, the solid materials end up being collected in the fractures, as shown in FIG. 12. This is also shown in Mastowski M., Kasza P., Wilk K, “Studies on the effect of the proppant embedment phenomenon on the effective packed fracture in shale rock,” Acta Geodyn. Geomater ., 15, No. 2 (190), 105— 115, 2018, DOI: 10.13168 / AGG.2018.0012. In FIG. 12, an example rock formation 1200 isillustrated as having reservoir rock areas, e.g., rock 1210, 1220, 1230, 1240, that fill with particles of solid materials, e.g., particles 1250, 1260, 1270, to create a solid pack, e.g., in the space between.

[0119] There is a need to control the resistivity and / or conductivity of the fracture to control productivity of the lixiviant with electrokinetic forces being applied. Accordingly, there is a need for systems and methods for formation modification to mitigate conductive channels for electrokinetic in-situ mining.

[0120] FIG. 13 is a diagram of a rock formation in accordance with an example embodiment of the present disclosure.

[0121] In FIG. 13, an example rock formation 1300 is illustrated as having reservoir rock areas, e.g., rock 1310, 1320, 1330, 1340, that contain particles of solid materials, e g., particles 1350, 1360, 1370, to create a pack, e.g., in the space between. The spaces between are fractures in the permeable rock formation, e.g., in the target layer 135 of FIG. 1.

[0122] In example embodiments of the present disclosure, an interaction between at least one of a carrier fluid, Newtonian or non-Newtonian additives, a size distribution of solid particles in the fracture, a pressure in the fracture, or a speed of movement of the solid particles may be adjusted to control, improve, or optimize the packing process of the solid particles in the rock fractures. The presence of this solid pack may act to increase the resistivity of the fracture simply by reducing the cross-section of a high conductivity lixiviant injected into the rock formation.

[0123] In example embodiments, the solid particles, e.g., particles 1350, 1360, 1370, may be coated with materials that may agglomerate and bind them under downhole conditions. In the FIG. 13, example, a coating 1380 is shown on the particles 1350. Applying resin-coated proppant is one example of this technique. In some example embodiments, the coating may have an insulative property, which may increase resistivity of the packed particles. Applying a coating may further reduce the electric conductivity, and may thus raise resistivity, of the fracture relative to the un-coated case. A coating thicker than is typically used in an oilfield mining operation may be applied to improve this insulating ability, as hydraulic conductivity is a desired parameter in an oilfield mining operation, but the low flows in in-situ mining accommodate significantly lower flows. In an example embodiment, the coating may be applied to a general space, as with theparticles 1350 with coating 1380 applied. In some example embodiments, excess coating material may be removed, e.g., suctioned while in a liquid form, to leave the particles individually coated, as shown for particles 1370 and coating 1390 in FIG. 12, with spaces therebetween having high resistivity due to the spacing enforced by the coating. The particles 1360 are illustrated as having a coating 1390 that may allow direct contact of at least some particles, but the particles 1360 are prevented from being packed more densely by the presence of the coating 1390.

[0124] An insulating material, e.g., material 1395, for example, a polymer material, may also be applied to further reduce the electrical conductivity of the resultant solid pack. The application of an insulating material in the interstitial spaces between the particles may be at the expense of additional hydraulic flow resistance. The insulating material may be provided in the interstitial spaces with or without a coating being also applied to the particles. The insulating material may be a liquid, gel, or solid, and may fill all or part of the spaces between the particles.

[0125] Example embodiments of the present disclosure may also cause a change in a hydraulic flow path of the lixiviant. The same or substantially similar modifications that alter the electrical path may also alter the hydraulic flow path, producing effects similar to what the self-diverting lixiviant is intended to do, but may not include a chemical reaction with the rock formation itself. In hydraulic fracturing, there is generally a desire to decrease the hydraulic flow resistance. However, within in-situ mining, it may be beneficial to produce a pack of particles in the fractures that delivers a controlled level of increased hydraulic flow resistance, in addition to an increase in electrical resistance. While it may be undesirable to completely block the fractures to either hydraulic flow or electrical flow, example embodiments may make the bulk rock a more feasible and / or attractive flow path for the lixiviant than in an untreated case.

[0126] FIG. 14 illustrates certain components that may be included within a computer system according to an example embodiment of the present disclosure.

[0127] FIG. 14 illustrates certain components that may be included within a computer system 1400, which may be used to control features according to embodiments of the present disclosure, such as the features discussed with reference to FIGs. 1-13. One or more computer systems 1400 may be used to implement the various devices, components, and systems described herein.

[0128] The computer system 1400 includes a processor 1401 . The processor 1401 may be a single processor or may include multiple processors and / or sub-processors. The processor 1401 may be a general-purpose single- or multi-chip microprocessor (e.g., an Advanced RISC (Reduced Instruction Set Computer) Machine (ARM)), a special -purpose microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc. The processor 1401 may be referred to as a central processing unit (CPU). Although just a single processor 1401 is shown in the computer system 1400 of FIG. 14, in an alternative configuration, a combination of processors (e.g., an ARM and DSP) could be used. In one or more embodiments, the computer system 1400 further includes one or more graphics processing units (GPUs), which can provide processing services related to both entity classification and graph generation.

[0129] The computer system 1400 also includes memory 1403 in electronic communication with the processor 1401. The memory 1403 may be any electronic component capable of storing electronic information. For example, the memory 1403 may be embodied as random access memory (RAM), read-only memory (ROM), magnetic disk storage media, optical storage media, flash memory devices in RAM, on-board memory included with the processor, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM) memory, registers, at least one non-transitory computer-readable and / or processor-readable medium, and so forth, including combinations thereof. The memory may include a single memory devices or multiple memory devices.

[0130] Instructions 1405 and data 1407 may be stored in the memory 1403. The instructions 1405 may be executable by the processor 1401 to implement some or all of the functionality disclosed herein. Executing the instructions 1405 may involve the use of the data 1407 that is stored in the memory 1403. Any of the various examples of modules and components described herein may be implemented, partially or wholly, as instructions 1405 stored in memory 1403 and executed by the processor 1401. Any of the various examples of data described herein may be among the data 1407 that is stored in memory 1403 and used during execution of the instructions 1405 by the processor 1401.

[0131] A computer system 1400 may also include one or more communication interfaces 1409 for communicating with other electronic devices. The communication interface(s) 1409 may be basedon wired communication technology, wireless communication technology, or both. Some examples of communication interfaces 1409 include a Universal Serial Bus (USB), an Ethernet adapter, a wireless adapter that operates in accordance with an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless communication protocol, a Bluetooth® wireless communication adapter, and an infrared (IR) communication port.

[0132] A computer system 1400 may also include one or more input devices 1411 and one or more output devices 1413. Some examples of input devices 1411 include a keyboard, mouse, microphone, remote control device, button, joystick, trackball, touchpad, and lightpen. Some examples of output devices 1413 include a speaker and a printer. One specific type of output device that is typically included in a computer system 1400 is a display device 1415. Display devices 1415 used with embodiments disclosed herein may utilize any suitable image projection technology, such as liquid crystal display (LCD), light-emitting diode (LED), gas plasma, electroluminescence, or the like. A display controller 1417 may also be provided, for converting data 1407 stored in the memory 1403 into text, graphics, and / or moving images (as appropriate) shown on the display device 1415.

[0133] The various components of the computer system 1400 may be coupled together by one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For the sake of clarity, the various buses are illustrated in FIG. 14 as a bus system 1419.

[0134] The following are sections in accordance with at least one embodiment of the present disclosure. Any of the sections relating to any of the first to fourth example embodiments below may be employed individually or in any combination, e.g., within and among the first to fourth example embodiments, within the scope of this disclosure.

[0135] At least a first example embodiment may include one or more of the following:

[0136] Clause 1 : A method for operating a system for in-situ mining in a rock formation in an area of interest, the method including: receiving a lixiviant from a lixiviant source at a first well extending downward from a ground surface in the area of interest, perform at least one of: injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material, or applying an electricfield to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode, receiving the solution via the second well extending downward from the ground surface in the area of interest, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

[0137] Clause 2: The method of clause 1, wherein the timing sequence includes alternating durations of injection of the lixiviant with durations of application of the electric field.

[0138] Clause 3: The method of any of clauses 1-2, wherein a first duration of injection of the lixiviant does not overlap with a first duration of application of the electric field.

[0139] Clause 4: The method of any of clauses 1-3, wherein a third duration of injection of the lixiviant overlaps with a fourth duration of application of the electric field.

[0140] Clause 5: The method of any of clauses 1-4, wherein at least two durations of application of the electric field last for different amounts of time.

[0141] Clause 6: The method of any of clauses 1-5, wherein at least two durations of injection of the lixiviant last for different amounts of time.

[0142] Clause 7: The method of any of clauses 1-6, wherein a composition of the lixiviant is different between at least two durations of injection of the lixiviant.

[0143] Clause 8: The method of any of clauses 1-7, wherein a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

[0144] Clause 9: The method of any of clauses 1-8, wherein a strength of the electric field is different between at least two durations of application of the electric field.

[0145] Clause 10: The method of any of clauses 1-9, wherein atype of the electric field is different between at least two durations of application of the electric field.

[0146] Clause 11 : The method of any of clauses 1 -10, wherein at least one of the composition of the lixiviant, the flow rate of the lixiviant, the timing of injection of the lixiviant, the strength of the electric field, the type of the electric field, or the timing of the application of the electric field is different between at least two durations of the injection of the lixiviant or the application of the electric field based on performing a measurement performed over time or at a predetermined point in time.

[0147] Clause 12: The method of clause 11, wherein the performing the measurement includes: measuring a voltage and a current in the first and second wells, and determining resistivity of the rock formation based on the measured voltage and current.

[0148] Clause 13: The method of clause 11, wherein the performing the measurement includes: measuring pressure in the first and second wells, and based on the measured pressure, performing at least one of: identifying at least one flow regime, or determining at least one characteristic of the rock formation.

[0149] Clause 14: The method of clause 11, wherein the performing the measurement includes: measuring temperature and pH values in the first and second wells, and based on the measured temperature and pH values, determining at least one of: a flow of the lixiviant in the rock formation, or effectiveness of an electrokinetic process caused by the application of the electric field.

[0150] Clause 15: The method of clause 11, wherein the performing the measurement includes: measuring at least one of a composition of the lixiviant or a property related to the composition of the lixiviant in the first well and at least one of a composition of the solution or a property related to the composition of the solution in the second well, and based on the measurements, determine at least one of: a penetration of the lixiviant into the ore, an actual kinetic parameter of the metal leaching process, existence of at least one of a flow highway or a flow barrier in the rock formation, clogging of part of a rock pore system in the rock formation, or potential damage to the first well, the second well, or another part of the system.

[0151] Clause 16: The method of any of clauses 1-15, further including: sectioning the area of interest into a plurality of zones, and independently operating each zone according to a respective timing sequence.

[0152] Clause 17: The method of clause 16, further including independently measuring each zone.

[0153] Clause 18: A system for in-situ mining of a rock formation in an area of interest, including: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant from a lixiviant source, perform at least one of: injecting the lixiviant into a permeable layer of the rock formation to dissolve a target material to form a solution containing the lixiviant and the target material, or operating as a first electrode to apply an electric field to at least one of the lixiviant or the solution, and a second well extending downward from the ground surface in the area of interest, the second well configured to: when the first well is operating as a first electrode, operate as a second electrode to apply the electric field to at least one of the lixiviant or the solution, receive the solution, and pumping the solution to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

[0154] Clause 19: The system of clause 18, wherein the timing sequence includes alternating durations of injection of the lixiviant with durations of application of the electric field.

[0155] Clause 20: The system of any of clauses 18-19, wherein the timing sequence includes at least one of: a first duration of injection of the lixiviant not overlapping with a first duration of application of the electric field, or a third duration of injection of the lixiviant overlapping with a fourth duration of application of the electric field.

[0156] Clause 21 : The system of any of clauses 18-20, wherein at least two durations of application of the electric field last for different amounts of time.

[0157] Clause 22: The system of any of clauses 18-21, wherein at least two durations of injection of the lixiviant last for different amounts of time.

[0158] Clause 23: The system of any of clauses 18-22, wherein at least one of a composition or a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

[0159] Clause 24: The system of any of clauses 18-23, wherein at least one of a strength and a type of the electric field is different between at least two durations of application of the electric field.

[0160] Clause 25: The system of any of clauses 18-24, wherein: the area of interest is sectioned into a plurality of zones, and each zone is independently operable according to a respective timing sequence.

[0161] Clause 26: The system of clause 25, wherein a composition of the lixiviant is provided on a zone-by-zone basis.

[0162] Clause 27: The system of any of clauses 18-26, wherein: the first well includes an injection well, and the second well includes a production well.

[0163] Clause 28: The system of any of clauses 18-27, wherein: one of the first electrode and the second electrode includes an anode, and the other of the first electrode and the second electrode includes a cathode.

[0164] At least a second embodiment may include one or more of the following:

[0165] Clause 1 : A method for in-situ mining in a rock formation in an area of interest, the method including: receiving a lixiviant from a lixiviant source at a first well extending downward from a ground surface in the area of interest, injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve the target material to form a solution containing the lixiviant and the target material, applying an electric field to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode, the applying the electric field including at least one of: applying an alternating current (AC) waveform, or applying a time-varying direct current (DC) waveform, receiving the solution via the second well extending downward from the ground surface in the area of interest, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant.

[0166] Clause 2: The method of clause 1 , wherein the applying the electric field includes changing a type of the electric field over time.

[0167] Clause 3 : The method of any of clauses 1-2, wherein the applying the electric field further includes applying a time-invariant DC waveform.

[0168] Clause 4: The method of any of clauses 1-3, wherein the applying the time-varying DC waveform includes applying a first voltage and a second voltage, the first voltage being higher than the second voltage.

[0169] Clause 5: The method of clause 4, wherein the second voltage is a positive voltage.

[0170] Clause 6: The method of clause 4, wherein the second voltage is a negative voltage.

[0171] Clause 7: The method of any of clauses 1-6, further including: operating one of the first well and the second well as an anode, and operating the other of the first well and the second well as a cathode.

[0172] Clause 8: A system for in-situ mining in a rock formation in an area of interest, including: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant from a lixiviant source, inject the lixiviant into a permeable layer of the rock formation containing a target material to dissolve the target material to form a solution containing the lixiviant and the target material, and operate as a first electrode to apply an electric field to at least one of the lixiviant or the solution, the applying the electric field including at least one of: applying an alternating current (AC) waveform, or applying a time-varying direct current (DC) waveform, and a second well extending downward from the ground surface in the area of interest, the second configured to: receive the solution, operate as a second electrode to apply the electric field to at least one of the lixiviant or the solution, and pump the solution to a processing plant to separate the target material from the lixiviant.

[0173] Clause 9: The system of clause 8, wherein the applying the electric field includes changing a type of the electric field over time.

[0174] Clause 10: The system of any of clauses 8-9, wherein the applying the electric field further includes applying a time-invariant DC waveform.

[0175] Clause 11 : The system of any of clauses 8-10, wherein the applying the time-varying DC waveform includes applying a first voltage and a second voltage, the first voltage being higher than the second voltage.

[0176] Clause 12: The system of clause 11, wherein the second voltage is a positive voltage.

[0177] Clause 13 : The system of clause 11, wherein the second voltage is a negative voltage.

[0178] Clause 14: The system of any of clauses 8-13, wherein: one of the first well and the second well includes an anode, and the other of the first well and the second well includes a cathode.

[0179] At least a third embodiment may include one or more of the following:

[0180] Clause 1 : A method for in-situ mining in a rock formation in an area of interest, the method including: receiving a lixiviant in fluid form from a lixiviant source at a first well extending downward from a ground surface in the area of interest, injecting the lixiviant into the rock formation via the first well to dissolve the target material to form a solution containing the lixiviant and the target material, allow the lixiviant to increase in viscosity such that the lixiviant self-diverts from larger fractures in the rock formation into smaller fractures in the rock formation to dissolve the target material in the smaller fractures to form the solution, receiving the solution via a second well extending downward from the ground surface in the area of interest, pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant.

[0181] Clause 2. The method of clause 1, further including: converting remaining increased- viscosity lixiviant into a lower-viscosity form, receiving the converted lixiviant via the second well, and pumping the converted lixiviant out of the rock formation via the second well.

[0182] Clause 3. The method of any of clauses 1-2, wherein lixiviant includes a liquid material that increases viscosity in-situ to become self-diverting.

[0183] Clause 4. The method of any of clauses 1-3, wherein the lixiviant includes an emulsified acid.

[0184] Clause 5. The method of any of clauses 1-3, wherein the lixiviant includes a viscoelastic diverting acid (VDA).

[0185] Clause 6. The method of any of clauses 1 -3, wherein the lixiviant includes an emulsified ferric chloride.

[0186] Clause 7. The method of any of clauses 1-3, wherein the lixiviant includes an emulsified hydrochloric acid.

[0187] Clause 8. The method of any of clauses 1-7, further including: sectioning the area of interest into a plurality of zones, and providing a respective composition of the lixiviant on a zone-by-zone basis.

[0188] Clause 9. The method of any of clauses 1-8, further including: applying electrokinetic in- situ leaching (EK-ISL) to the first well and the second well, wherein one of the first well and the second well operates as an anode, and wherein the other of the first well and the second well operates as a cathode.

[0189] Clause 10. The method of any of clauses 1-9, further including: operating the first well as an injection well, and operating the second well as a production well.

[0190] Clause 11. The method of any of clauses 1-10, further including: arranging a plurality of control wells at a periphery of the area of interest, and monitoring groundwater in the area of interest via the control wells.

[0191] Clause 12. A system for in-situ mining in a rock formation in an area of interest, including: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant in fluid form from a lixiviant source, inject the lixiviant into the rock formation containing a target material to: dissolve the target material to form a solution containing the lixiviant and the target material, and allow the lixiviant to increase in viscosity such that the lixiviant self-diverts from larger fractures in the rock formation into smaller fractures in the rock formation to dissolve the target material in the smaller fractures to form the solution, and a second well extending downward from the ground surface in the area of interest, the second well configured to: receive the solution, and pump the solution to a processing plant to separate the target material from the lixiviant.

[0192] Clause 13. The system of clause 12, wherein: remaining increased-viscosity lixiviant is converted into a lower-viscosity form, and the second well is further configured to: receive the converted lixiviant, and pump the converted lixiviant out of the rock formation.

[0193] Clause 14. The system of any of clauses 12-13, wherein lixiviant includes a liquid material that increases viscosity in-situ to become self-diverting.

[0194] Clause 15. The system of any of clauses 12-14, wherein the lixiviant includes an emulsified acid.

[0195] Clause 16. The system of any of clauses 12-14, wherein the lixiviant includes a viscoelastic diverting acid (VDA).

[0196] Clause 17. The system of any of clauses 12-14, wherein the lixiviant includes an emulsified ferric chloride.

[0197] Clause 18. The system of any of clauses 12-14, wherein the lixiviant includes an emulsified hydrochloric acid.

[0198] Clause 19. The system of any of clauses 12-18, wherein: the area of interest is sectioned into a plurality of zones, and a composition of the lixiviant is provided on a zone-by-zone basis.

[0199] Clause 20. The system of any of clauses 12-19, wherein: electrokinetic in-situ leaching (EK-ISL) is applied to the first well and the second well, one of the first well and the second well includes an anode, and the other of the first well and the second well includes a cathode.

[0200] Clause 21. The system of any of clauses 12-20, wherein: the first well includes an injection well, and the second well includes a production well.

[0201] Clause 22. The system of any of clauses 12-21, wherein: a plurality of control wells is arranged at a periphery of the area of interest, and the control wells are configured to monitor groundwater in the area of interest.

[0202] At least a fourth embodiment may include one or more of the following:

[0203] Clause 1 : A method for in-situ mining in a rock formation in an area of interest, the method including: controlling at least one of a resistivity or a hydraulic flow of a fracture in the rock formation, the fracture containing a target material, receiving a lixiviant from a lixiviant source at a first well extending downward from a ground surface in the area of interest, injecting the lixiviant into the fracture via the first well to dissolve the target material to form a solution containing the lixiviant and the target material, applying an electric field to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode, receiving the solution via the second well extending downward from the ground surface in the area of interest, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant.

[0204] Clause 2: The method of clause 1, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes increasing or decreasing the resistivity or the hydraulic flow according to an operational parameter.

[0205] Clause 3: The method of any of clauses 1-2, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes adjusting an interaction between at least one of a carrier fluid, Newtonian or non-Newtonian additives, a size distribution of solid particles in the fracture, a pressure in the fracture, or a speed of movement of the solid particles to control a packing process of the solid particles in the fracture.

[0206] Clause 4: The method of any of clauses 1-3, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes reducing a cross-section of the lixiviant injected into the fracture.

[0207] Clause 5: The method of any of clauses 1-4, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes applying a coating to particles in the fracture.

[0208] Clause 6: The method of clause 5, wherein the applying the coating to the particles in the fracture includes agglomerating and binding the particles under downhole conditions.

[0209] Clause 7: The method of clause 6, wherein the coating includes a resin-coated proppant.

[0210] Clause 8: The method of clause 7, wherein the applying the coating to the particles in the fracture reduces electric conductivity and raises resistivity of the fracture.

[0211] Clause 9: The method of any of clauses 5-8, wherein the coating has an insulative property.

[0212] Clause 10: The method of any of clauses 5-9, wherein excess coating is removed from the fracture before the lixiviant is injected.

[0213] Clause 11 : The method of any of clauses 1-10, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes applying an insulating material to spaces between particles in the fracture.

[0214] Clause 12: The method of clause 11, wherein the insulating material includes a polymer material.

[0215] Clause 13: The method of any of clauses 1-12, wherein the lixiviant includes a high conductivity lixiviant.

[0216] Clause 14: A system for in-situ mining in a rock formation in an area of interest, including: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant from a lixiviant source, inject the lixiviant into a fracture in the rock formation containing a target material to dissolve the target material to form a solution containing the lixiviant and the target material, operate as a first electrode to apply an electric field to at least one of the lixiviant or the solution, and a second well extending downward from the ground surface in the area of interest, the second well configured to: operate as a second electrode to apply the electric field to at least one of the lixiviant or the solution, receive the solution, and pump the solution to a processing plant to separate the target material from the lixiviant, wherein at least one of a resistivity or a hydraulic flow of the fracture is controlled by the system.

[0217] Clause 15: The system of clause 14, wherein the at least one of the resistivity or the hydraulic flow of the fracture is controlled to be increased or decreased according to an operational parameter.

[0218] Clause 16: The system of any of clauses 14-15, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes adjusting an interaction between atleast one of a carrier fluid, Newtonian or non-Newtonian additives, a size distribution of solid particles in the fracture, a pressure in the fracture, or a speed of movement of the solid particles to control a packing process of the solid particles in the fracture.

[0219] Clause 17: The system of any of clauses 14-16, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes reducing a cross-section of the lixiviant injected into the fracture.

[0220] Clause 18: The system of any of clauses 14-17, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes applying a coating to particles in the fracture.

[0221] Clause 19: The system of clause 18, wherein excess coating is removed from the fracture before the lixiviant is injected by the first well.

[0222] Clause 20: The system of any of clauses 14-19, wherein the controlling the at least one of the resistivity or the hydraulic flow of the fracture includes applying an insulating material to spaces between particles in the fracture.

[0223] Clause 21 : The system of clause 20, wherein the insulating material includes a polymer material.

[0224] Systems and software, e.g., implemented on a non-transitory computer-readable medium, for performing the methods discussed herein are also within the scope of embodiments of the present disclosure.

[0225] Embodiments of the present disclosure may thus utilize a special purpose or general- purpose computing system including computer hardware, such as, for example, one or more processors and system memory. Embodiments within the scope of the present disclosure also include physical and other computer-readable media for carrying or storing computer-executable instructions and / or data structures, including applications, tables, data, libraries, or other modules used to execute particular functions or direct selection or execution of other modules. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer system. Computer-readable media that store computer-executableinstructions (or software instructions) are physical storage media. Computer-readable media that carry computer-executable instructions are transmission media. Thus, by way of example, and not limitation, embodiments of the present disclosure can include at least two distinctly different kinds of computer-readable media, namely physical storage media or transmission media. Combinations of physical storage media and transmission media should also be included within the scope of computer-readable media.

[0226] Both physical storage media and transmission media may be used to temporarily store or carry software instructions in the form of computer readable program code that allows performance of embodiments of the present disclosure. Physical storage media may further be used to persistently or permanently store such software instructions. Examples of physical storage media include physical memory (e.g., RAM, ROM, EPROM, EEPROM, etc.), optical disk storage (e.g., CD, DVD, HDDVD, Blu-ray, etc.), storage devices (e.g., magnetic disk storage, tape storage, diskette, etc.), flash or other solid-state storage or memory, or any other non-transmission medium which can be used to store program code in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer, whether such program code is stored as or in software, hardware, firmware, or combinations thereof.

[0227] A “network” or “communications network” may generally be defined as one or more data links that enable the transport of electronic data between computer systems and / or modules, engines, and / or other electronic devices. When information is transferred or provided over a communication network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computing device, the computing device properly views the connection as a transmission medium. Transmission media can include a communication network and / or data links, carrier waves, wireless signals, and the like, which can be used to carry desired program or template code means or instructions in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer.

[0228] Further, upon reaching various computer system components, program code in the form of computer-executable instructions or data structures can be transferred automatically or manually from transmission media to physical storage media (or vice versa). For example, computer-executable instructions or data structures received over a network or data link can be buffered in memory (e.g., RAM) within a network interface module (NIC), and then eventually transferred to computer system RAM and / or to less volatile physical storage media at a computer system. Thus, it should be understood that physical storage media can be included in computer system components that also (or even primarily) utilize transmission media.

[0229] One or more specific embodiments of the present disclosure are described herein. These described embodiments are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, not all features of an actual embodiment may be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous embodimentspecific decisions will be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one embodiment to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0230] The articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.

[0231] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims. Any trademarks mentioned herein are the property of their respective owners.

[0232] The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.

[0233] The present disclosure may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. Changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. CLAIMS1. A method for operating a system for in-situ mining in a rock formation in an area of interest, the method comprising: receiving a lixiviant from a lixiviant source at a first well extending downward from a ground surface in the area of interest; performing at least one of: injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material; or applying an electric field to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode; receiving the solution via the second well extending downward from the ground surface in the area of interest; and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

2. The method of claim 1, wherein the timing sequence comprises alternating durations of injection of the lixiviant with durations of application of the electric field.

3. The method of claim 1, wherein a first duration of injection of the lixiviant is not overlapping with a first duration of application of the electric field.

4. The method of claim 1, wherein a third duration of injection of the lixiviant overlaps with a fourth duration of application of the electric field.

5. The method of claim 1, wherein at least two durations of application of the electric field last for different amounts of time.

6. The method of claim 1 , wherein at least two durations of injection of the lixiviant last for different amounts of time.

7. The method of claim 1, wherein a composition of the lixiviant is different between at least two durations of injection of the lixiviant.

8. The method of claim 1, wherein a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

9. The method of claim 1, wherein a strength of the electric field is different between at least two durations of application of the electric field.

10. The method of claim 1, wherein a type of the electric field is different between at least two durations of application of the electric field.

11. The method of claim 1, wherein at least one of a composition of the lixiviant, a flow rate of the lixiviant, a timing of injection of the lixiviant, a strength of the electric field, a type of the electric field, or a timing of application of the electric field is different between at least two durations of the injection of the lixiviant or application of the electric field based on performing a measurement performed over time or at a predetermined point in time.

12. The method of claim 11, wherein the performing the measurement comprises: measuring a voltage and a current in the first and second wells; and determining resistivity of the rock formation based on the measured voltage and current.

13. The method of claim 11, wherein the performing the measurement comprises: measuring pressure in the first and second wells; and based on the measured pressure, performing at least one of: identifying at least one flow regime; or determining at least one characteristic of the rock formation.

14. The method of claim 11 , wherein the performing the measurement comprises: measuring temperature and pH values in the first and second wells; and based on the measured temperature and pH values, determining at least one of: a flow of the lixiviant in the rock formation; or effectiveness of an electrokinetic process caused by the application of the electric field.

15. The method of claim 11, wherein the performing the measurement comprises: measuring at least one of a composition of the lixiviant or a property related to the composition of the lixiviant in the first well and at least one of a composition of the solution or a property related to the composition of the solution in the second well; and based on the measurements, determine at least one of: a penetration of the lixiviant into an ore; an actual kinetic parameter of a metal leaching process; existence of at least one of a flow highway or a flow barrier in the rock formation; clogging of part of a rock pore system in the rock formation; or potential damage to the first well, the second well, or another part of the system.

16. The method of claim 1, further comprising: sectioning the area of interest into a plurality of zones; and independently operating each zone according to a respective timing sequence.

17. The method of claim 16, further comprising independently measuring each zone.

18. A system for in-situ mining of a rock formation in an area of interest, comprising: a first well extending downward from a ground surface in the area of interest, the first well configured to: receive a lixiviant from a lixiviant source; perform at least one of:injecting the lixiviant into a permeable layer of the rock formation to dissolve a target material to form a solution containing the lixiviant and the target material; or operating as a first electrode to apply an electric field to at least one of the lixiviant or the solution; and a second well extending downward from the ground surface in the area of interest, the second well configured to: when the first well is operating as a first electrode, operate as a second electrode to apply the electric field to at least one of the lixiviant or the solution; receive the solution; and pump the solution to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.

19. The system of claim 18, wherein the timing sequence comprises alternating durations of injection of the lixiviant with durations of application of the electric field.

20. The system of claim 18, wherein the timing sequence comprises at least one of: a first duration of injection of the lixiviant not overlapping with a first duration of application of the electric field; or a third duration of injection of the lixiviant overlapping with a fourth duration of application of the electric field.

21. The system of claim 18, wherein at least two durations of application of the electric field last for different amounts of time.

22. The system of claim 18, wherein at least two durations of injection of the lixiviant last for different amounts of time.

23. The system of claim 18, wherein at least one of a composition or a flow rate of the lixiviant is different between at least two durations of injection of the lixiviant.

24. The system of claim 18, wherein at least one of a strength and a type of the electric field is different between at least two durations of application of the electric field.

25. The system of claim 18, wherein: the area of interest is sectioned into a plurality of zones; and each zone is independently operable according to a respective timing sequence.

26. The system of claim 25, wherein a composition of the lixiviant is provided on a zone-by-zone basis.

27. The system of claim 18, wherein: the first well comprises an injection well; and the second well comprises a production well.

28. The system of claim 18, wherein: one of the first electrode and the second electrode comprises an anode; and another of the first electrode and the second electrode comprises a cathode.

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