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CA-3071025-C - SYSTEMS AND METHODS FOR IMPROVEMENT OF METAL RECOVERY AND STABILITY OF PILES

CA3071025CCA 3071025 CCA3071025 CCA 3071025CCA-3071025-C

Abstract

In embodiments, pressurized fluid containing reagents of formulated -mixtures of solids, liquids and gasses are delivered into a cased well then into the heap or pile to open or stimulate, new horizontal and vertical fluid pathways, channels, plus drains from the open bottom of the well to the bottom of the heap or pile for fluid collection. This delivery method may also drain any fluids that are retained and pooled in the heap or pile. The removal of pooled fluids will increase the inter-particle cohesion and friction in the heap or pile, thus adding geotechnical stability and resistance to movement of the heap or pile. The eased wells may also add-shear strength to the collective to retard movement of the heap or pile.

Inventors

  • Thomas Joseph Seal

Assignees

  • DIFFERENTIAL ENGINEERING INC.

Dates

Publication Date
20260505
Application Date
20180730
Priority Date
20170731

Claims (20)

  1. CLAIMS: 1. A system for rechanneling fluid flow in a heap or pile, comprising: a drilled well casing positioned substantially vertically within the heap or pile, the drilled well casing comprising an open top, an open bottom, and at least one perforation zone comprising a plurality of perforations along a vertical section of the drilled well casing; a pressurized fluid; a pipe positioned within the drilled well casing, the pipe configured to receive the pressurized fluid; a first isolation mechanism configured to seal the drilled well casing above the at least one perforation zone; and a control valve configured to selectively direct the pressurized fluid into an interior of the heap or pile through the at least one perforation zone or both the at least one perforation zone and the open bottom, wherein the control valve is configured to close or employ a second isolation mechanism to seal the drilled well casing below the at least one perforation zone to isolate a first flow of the pressurized fluid through perforations among the plurality of perforations of the at least one perforation zone, wherein the control valve is further configured to open or not employ the second isolation mechanism to direct a second flow of the pressurized fluid through the open bottom, and wherein the first flow fluidizes materials within an interior of the heap or pile and creates a plurality of substantially horizontal fluid channels in the materials in the interior of the heap or pile, and wherein the second flow creates a substantially vertical fluid channel within the interior of the heap or pile.
  2. 2. The system of claim 1, wherein the pressurized fluid comprises reagents to leach a target material from the heap or pile, including one or more formulated mixtures of solids, liquids, gases, or slurries.
  3. 3. The system of claim 1, wherein when the second isolation mechanism is not employed, the pressurized fluid pumped into the pipe flows through both the perforations of the drilled well casing and the open bottom to create a plurality of horizontal and vertical fluid channels. 9040202 Date Re9ue/Date Received 2023-12-29
  4. 4. The system of claim 1, wherein the heap or pile is above one or more of a foundation, a collection system, a liner, a natural contour of native earth, or compacted native earth.
  5. 5. The system of claim 1, wherein the heap or pile comprises a volume offluid above a volume of material having low permeability, wherein the volume of fluid does not drain through the volume of material.
  6. 6. The system of claim 1, wherein the control valve controls one or more of a rate and volume of the pressurized fluid.
  7. 7. The system of claim 1, further comprising: a collection system at a bottom of the heap or pile, the collection system configured to receive fluid from at least one of the horizontal or vertical fluid channels.
  8. 8. The system of claim 1, wherein the drilled well casing has a shear strength greater than a shear strength of the materials in the interior of the heap or pile.
  9. 9. The system of claim 1, wherein the pressurized fluid comprises one or more of a mineral reagent, a metal reagent, a lixiviant, or an added biochemical, chemical, or microbiological agent to alter one or more conditions of pH, Eh, chemistry, biochemistry, microbiological, or volume of the pressurized fluid.
  10. 10. The system of claim 1, wherein at least one of the first and second isolation mechanism comprises one or more of a plug, stopper, packer, stem, stent, or inflated or fluid filled hose, conduit or pipe to seal at least a portion of the drilled well casing.
  11. 11. The system of claim 1, wherein the first isolation mechanism is further configured to enable the pressurized fluid to improve a solubility of a target material to reagents or agents in the pressurized fluid.
  12. 12. The system of claim 1, further comprising a seal for the open top, the open bottom or both the open top and the open bottom to temporarily or permanently protect short or long term pile stability by preventing the drilled well casing from being exposed to air, meteoric water, bacteria, yeasts, molds or human interaction. 21 9040202 Date Re9ue/Date Received 2023-12-29
  13. 13. The system of claim 12, wherein the pile stability includes one or more of physical, chemical, biochemical, microbiological, and geotechnical stability.
  14. 14. The system of claim 12, wherein the seal is one or more of a cap, a plug, a stopper, a stem, or an inflated or fluid filled hose, conduit, pipe, or another sealing material.
  15. 15. A method for rechanneling fluid flow in a heap or pile, comprising: positioning a drilled well casing substantially vertically within the heap or pile, wherein the drilled well casing comprises an open top, an open bottom, and at least one perforation zone comprising a plurality of perforations along a vertical section of the drilled well casing; positioning a pipe within the drilled well casing; delivering a pressurized fluid to the pipe; employing a first isolation mechanism that is configured to seal the drilled well casing above the at least one perforation zone; and using a control valve to selectively direct the pressurized fluid into an interior of the heap or pile through the at least one perforation zone or both the at least one perforation zone and the open bottom, wherein the control valve is configured to close or employ a second isolation mechanism to seal the drilled well casing below the at least one perforation zone to isolate a first flow of the pressurized fluid through perforations among the plurality of perforations of the at least one perforation zone, wherein the control valve is further configured to open or not employ the second isolation mechanism to direct a second flow of the pressurized fluid through the open bottom, and wherein the first flow fluidizes materials within the interior of the heap or pile and creates a plurality of substantially horizontal fluid channels in the materials in the interior of the heap or pile and the second flow creates a substantially vertical fluid channel within the interior of the heap or pile.
  16. 16. The method of claim 15, further comprising: receiving pressurized fluid from at least one of the horizontal fluid channels and the vertical fluid channel at a collection system positioned at a bottom of the heap or pile.
  17. 17. The method of claim 16, further comprising: 22 9040202 Date Re9ue/Date Received 2023-12-29 draining fluid retained and pooled within the interior of the pile or heap with the received fluid passing through the vertical fluid channel through the open bottom of the drilled well casing to the collection system.
  18. 18. The method of claim 16, wherein the received fluid comprises at least one of a mineral or metal leached from the heap or pile.
  19. 19. The method of claim 16, further comprising: prior to delivering the pressurized fluid, stacking a segregated material at a specific location within the heap or pile to contact the pressurized fluid from at least one of the horizontal fluid channels and the vertical fluid channel.
  20. 20. The method of claim 19, wherein the segregated material comprises one or more of native soil, a potentially acid generating material (PAG), a chemical to optimize metal leaching, or a higher metal grade or mineral grade than a surrounding material in the heap or pile.

Description

SYSTEMS AND METHODS FOR IMPROVEMENT OF METAL RECOVERY AND STABIUT1·· OF PILES CROSS REFERENCE TO RELATED APPLICATIONS [0001] Th.is application clai:rn.s llle benefit ofU.S. Pn.wisional Patent Application No. 62/539,363, filed July 31, 2017. BACKGROUND (0002] A common technique t:br extracting metal fh.)m (-Yres and other ntineral material is heap leaching. In heap leaching, mined products as well as many industrial, cnmmerciaJ and residential materials are placed in piles and impoundments, prior to manufacturing and processing for market Materials may be placed in piles, dumps, landfills, sanitary landfills and impoundments for storage and disposal, both short and kmg term. Examples include mine waste rock <.i1unps, lllllnidpal ~olid. ,vaste chimps, ~md ~my .. placed dt~.mps or piles. An engineered heap of fragmented, an-consolidated rock or particulate nmterial may be constructed,, typically over an engineered liner and liquid collection system lbr metal, chemical and mineral extraction, A leach solution is applied to and percolated through the heap to contact the material and dissolve one or more n1etal and minerals of interest into the leach solution. Sprinklers are occasionally used for irrigation of the heapJ:mtdrip irrigation is .more comn1only used t:o minhnize evaporation and more uniformly distribute the leaching soJμth1n, The solution, called a "barren solution", containing metal and mineral dissolving reagents or lixiviants, percolates through the heap, leaches the target metal/chemical/mineral/substance, and dissolves other materials. This process, called the "leach cycle," can take bet\'veen a couple (.)f days t.o months or years depending on the material being. leached .. Waste nJck, industrial foedstoc:ks, and. aH types of ,vaste products rnay he st.m:iked in piles ,vith or without l.im.irs, depending on, for example, the material which makes up the pile., existing regulations and storage praclic.es, and short or long-tenn dis-pos:aL (00031 Theoretically, in heap leaching, the barren solutfon or fluid travels substantially vertically through the heap in a fairly unifom1 manner from each drip or irrigation point, v,1hich is based on the physical and mineral d1aracterization of the material stacked (Le., its size, voidage, perrneahilit.y, compaction, etc.) in the fonnation of the heap or 1n the material placed underneath each drip or irrigation point. In reality, ,vit.hin a relatively shon period. of time, a WO 2019/027932 PCT/0S2018/044441 path of least resistance, or a Mar vertical. chllt1net, .form.sin the heap. starting at each drip or irrigation point, and base(i on lhe formation or the material placed underneath the drip t)r irrigation point Each path of least resistance is likely to be near vertical for permeable material and uear horizontal for impermeable material, and as a result, large sections of the heap may receive lll) barren solution atler a period of time, and relatively !.ittle or no leaching of t:l1e target material mi1y otcu.r. Also, the leach soh1tiort1l1ay not 1,1:nifonnly contact ~1Hportfons oftlm heap because of pem1eahHity variations existing within tbe heap, such as volumes of clay material with low permeability. ln addition, within the heap or pile, there may he material that exhibit,; low perrneabiliiy and does not let: solution or flujd pass hy the force of gravjty, thus entraining or pooling the solution above the low'"'.penneable heap or pile material Such permeability variations may result in prefotential t1ow· of the leach solution through more permeable po1ti6ns of the heap, leaving volumes of under':"leached or w1~Ieacbed material hekhv less permeable pc.u1.ions. and ttreas of fluid retention and sa.l.mation above these less permeable pc.m.ions. [0004J Also, the chemical properties in some portions of the heap may be less responsive lo dissolution of the metal or mineral into the leach fluid, For example, \vben heap leaching copper with an acid leach solutiou. high alkaline pH spots within the heap may not. respond well to the acid leach solution and may lead to reduced permeability, chemical predptration, rockdecrepitating, migration of fines, heap ~ettlement a:nd compaction, l.eaving those portions 1.mder-lea~hed mun-le.ached as wen as volumes of solution retention and pools in the heap. Metals and minerals remaining in under-leached. un-.!eached portions as well as pools of fluid \Vith dissolved metals and minerals entrained .in a heap during and following heap leach operations often reprt"Sent a significant loss ohm-recovered inventory to a mining operation. [0005] 111 another example, piles of feedstock a11d ,vaste may be stacked in a mmmerto isolate the material from the environment. The piles are often covered and lit1ed to prevent meteoric \vnter from reacting with com,t.iu:iems in t:he pile and impacting and/or degrading surface and ground water. ln heap leac.hing, a heap coHection system c.ollects the resulting pregnant leach solution (i.e,, the solu