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.

1 . 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.