How to heap leaching materials

Abstract

A method for heap leaching metals from ROM material containing metal sulfide-bearing materials, such as copper sulfide-bearing minerals. The method includes forming a heap of ROM material or expanding an existing heap by adding ROM material to the heap. The method also includes leaching metals from the ROM material in the heap using an acidic leach solution to produce a pregnant leach solution containing the metals in solution, and recovering the metals from the pregnant leach solution. Pyrite already present in the ROM material generates acid and heat to facilitate the leaching of metals from the ROM material. The ROM material may be transported directly from the mine to a stockpile without changing the size of the material particles in the ROM material. The method may also include adding additional pyrite and other additives to facilitate the leaching of metals.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to Australian Patent Application No. 2023200579, filed February 3, 2023, and to U.S. Patent Application No. 18 / 105514, filed February 3, 2023.

[0002] (Technical field) The present invention relates to a method for heap leaching metals, such as copper, nickel, zinc, or cobalt, from run-of-mine ("ROM") materials containing metal sulfide-containing materials, such as metal sulfide minerals, to recover said metals from said materials.

[0003] The metalliferous material may be an ore.

[0004] The metal-bearing material may be waste material, for example, tailings or mineralized waste (mineralized waste that is uneconomical to process using processes currently utilized in the mine from which it was extracted).

[0005] The present invention particularly relates to a method of heap leaching run-of-mine ("ROM") material, i.e., material that is mined and then transferred to a heap of material without further size reduction other than that which occurs during mining of the material, as further described below, and optionally material that has been transferred to the heap through a processing station, for example to add microorganisms or other additives to the ROM material.

[0006] The present invention also relates to a heap leaching operation.

[0007] The present invention also relates to methods for mining ROM material and heap leaching the material. [Background technology]

[0008] The technical field of this invention is the production of metals such as copper, nickel, zinc, cobalt, etc. from metal sulfide-containing materials, such as metal sulfide minerals from run-of-mine ("ROM") materials.

[0009] The following description of the invention focuses on copper as an example of a metal in a metal sulfide-containing material, such as a metal sulfide mineral.

[0010] Copper is an increasingly important metal in the transition to a low-carbon global economy.

[0011] Lower average concentrations of copper in copper sulfide-bearing materials, such as copper sulfide-bearing minerals, in established mines and new copper mines (which term includes mines where copper is the only metal recovered, as well as mines where copper and other high-value metals (such as gold) are recovered) than previously exist, placing significant capital and operating cost pressures on the mining operators of such mines.

[0012] In many cases, the problem of low copper concentrations in copper sulfide-bearing materials, such as copper sulfide-bearing minerals, is complicated by the fact that copper is present in higher proportions of more refractory copper sulfide-bearing minerals (e.g., pyrite) than in the past, making processing to recover copper from these minerals more difficult and expensive.

[0013] Mining companies are also very conscious of the importance of operating mines with minimal environmental impact in the short and long term, which has an impact on recovery options and costs.

[0014] The economics faced by copper mining operators mean that there are significant amounts of copper sulfide-bearing material, including mined material and processed forms of mined material (e.g., crushed material), that make it uneconomical to recover copper using recovery options that were available prior to the present invention, and therefore processing to recover copper from the copper sulfide-bearing material is not undertaken.

[0015] The above statements are not an admission of common general knowledge in Australia or elsewhere. Summary of the Invention

[0016] The present invention was made as part of the applicant's research and development project relating to the leaching of copper from copper sulphide-bearing materials, particularly copper sulphide minerals.

[0017] This research and development project focuses specifically, but is not limited to, the leaching of copper from chalcopyrite (CuFeS2) (hereinafter referred to as "chalcopyrite material"), as it is notoriously difficult to obtain high copper recoveries from chalcopyrite material and chalcopyrite material is an important source of copper.

[0018] This research and development project has produced numerous inventions, some of which are summarized below. 1. International Applications PCT / US2021 / 043869 (WO2022 / 026810) and PCT / US2021 / 043869 (WO2022 / 026826), which disclose the effect of increasing pyrite on the bioleaching of agglomerated copper-bearing mined materials. 2. International Applications PCT / AU2016 / 051024 (WO2017 / 070747) and PCT / AU2018 / 050316 (WO2018 / 184071). These applications disclose the effect of increasing silver in the bioleaching of agglomerated copper-bearing mined materials. The application of International Application PCT / AU2018 / 050316 (WO2018 / 184071) also discloses an activator for activating silver, whereby the silver promotes copper extraction from the copper-bearing mined materials. 3. International Application PCT / AU2019 / 050383 (WO2019 / 213694). The specification discloses the effect of an additive (thiourea) on the dissolution of copper from copper minerals in copper-bearing mined material or from copper minerals in a concentrate of said material, thereby forming a complex between (a) sulfur derived from copper minerals in the copper-bearing mined material, and (b) the additive.

[0019] The disclosures of the patent specifications of the above international applications are incorporated herein by cross-reference.

[0020] Further work in research and development projects has recognized that the method of heap leaching of run-of-mine ("ROM") materials described herein is a viable method with many significant advantages.

[0021] Heap leaching of ROM material according to the present invention is a different approach from the heap leaching of agglomerates of mined material that is the focus of the above-mentioned international application.

[0022] The ROM material may be ore or waste material.

[0023] The term "ore" is understood herein to mean a naturally occurring rock or deposit containing one or more valuable metals that can be mined, reclaimed, processed, and sold at a profit. It is noted that the term "ore" is a relative term, and that material may be considered an ore (i.e., profitable material) at one time and a waste material at another time. It is also noted that the assessment of whether a material is an "ore" (i.e., profitable material) may depend on the mine from which the material is extracted, as well as the capital and operating costs of the mine (including whether the mine is a brownfield or greenfield mine).

[0024] ROM material can be obtained from any mining operation in a mine.

[0025] For example, the mining operation is an excavation and blasting operation in an open pit mine, and the ROM material is the rock formed when excavating and blasting the mine bench.

[0026] As a further example, the mining operation is one that involves the use of a continuous miner, and the ROM material is rock produced from the continuous miner.

[0027] As a further example, the mining operation may be a block caving operation in an underground mine, and the ROM material may be rock in rill piles at the mining point of the block cavern.

[0028] Broadly, the present invention provides a method for heap leaching metals from run-of-mine ("ROM") material from a mine containing metal sulfide-bearing material, such as metal sulfide minerals, as described herein, the method comprising: (a) creating a heap of ROM material or expanding an existing heap by adding ROM material to the heap; (b) a heap leaching process in which metals are leached from ROM material in a heap using an acidic leach liquor, where pyrite already present in the ROM material generates acid and heat that promotes leaching of metals from the ROM material, producing a pregnant leach liquor containing the metals in solution; Includes.

[0029] The term "ROM material" as used herein refers to material formed in mining operations, i. Directly transported from the mine to the heap; or ii. Directly transported from the mine to a stockpile and then directly to a heap; It is understood to mean rock material.

[0030] The term "ROM" material includes rocks produced when large rocks of ROM material that are too large to transport from a mine are crushed, for example, by a rock crusher.

[0031] The term "rock breaker" is understood herein to mean "a machine designed to manipulate large rocks, including breaking them into smaller rocks," and is distinct from a crusher.

[0032] The term "ROM" material includes ROM material that has been separated into fragments based on size.

[0033] In both cases, rock fragmentation and / or size segregation occurs and the resulting material is ROM material.

[0034] The method may also further include collecting the pregnant leach solution from the heap and recovering metals from the pregnant leach solution.

[0035] The method may include recovering metals from the pregnant leach solution by any suitable recovery option.

[0036] The recovery method may include extracting metals from the pregnant leach solution using a solvent to produce a metals-containing solvent stream and a raffinate.

[0037] The recovery method may include stripping the metal from the solvent to form a metal-containing solution and electrowinning the metal from the metal-containing solution.

[0038] The method may also include transferring the raffinate to a percolation step (b).

[0039] The method may include adding additional materials (additives) to the ROM material before, as, or after the heap is formed, or to the leachate.

[0040] The additional material (additive) may be additional pyrite.

[0041] For example, the heap forming step (a) may include forming a heap of ROM material that includes additional pyrite in addition to the pyrite in the ROM material, or expanding an existing heap by adding additional pyrite to the heap in addition to the ROM material and the pyrite in the ROM material.

[0042] The method may include adding additional pyrite, such as to the top of the heap, while the heap leaching step (b) is in progress.

[0043] The method may include adding additional pyrite to the ROM material prior to forming the heap in heap-forming step (a).

[0044] Pyrite is important for acid production and heat generation.

[0045] The pyrite generates heat within the heap through reactions within the heap, including reactions with the leachate.

[0046] To generate cash flow, it is desirable to reach a target heap temperature quickly. It is also desirable to maintain a substantially constant heap temperature over time. Temperature fluctuations can affect copper extraction rates and microbial health (if present in the heap).

[0047] Typically, higher heap temperatures result in higher copper extraction rates.

[0048] If microorganisms are present in the heap, their health may be affected by temperatures above or below the target temperature range, so this is an important consideration when selecting a target heap temperature.

[0049] The method may include selecting the amount of additional pyrite so that the heap reaches the target temperature quickly, i.e., in 500 days or less, more typically in 400 days or less, and more typically in 300 days or less.

[0050] The target temperature will depend on a variety of factors in a particular situation.

[0051] These factors may include one or more of the type of microorganism, the mineralogy of the material, the grade of the material (e.g., the concentration of metals in the material or the concentration of contaminants in the material), the acid dosage rate, and the pH of the leachate.

[0052] The target temperature is expressed as the average heap temperature and may be in the range of 60-80°C.

[0053] The term "average" temperature is understood herein to take into account that there may be variations in temperature throughout the heap, and thus an average temperature of, for example, 70°C, takes into account that the temperature may be different in one part of the heap than in another, and the average temperature is the average of multiple temperatures measured within the heap.

[0054] Generally, the method comprises the following steps: (a) Where ROM material is formed in mining operations (e.g., slumped material formed after excavating and blasting a mine bench); (b) Where the ROM material is loaded onto a transport vehicle (such as a haul truck or load-dump vehicle), conveyor, or other means of transportation, additional pyrite is added either when the ROM material is loaded onto the means of transportation or after it has been loaded onto the means of transportation; (c) When ROM material is being transported from a loading point within a mine to a heap, stockpile, or intermediate station, or when ROM material is being transported from a stockpile or intermediate station to a heap; (d) When ROM material is being added to the heap, (e) At an intermediate station located between the loading area and the heap, (f) At an intermediate station located between the stockpile and the heap, (g) In a blending operation involving blending ROM material with additional pyrite and then adding the blend to the heap; (h) In stockpiles: (i) in the heap (e.g., in the leachate or directly as a separate additive when or after the heap is formed, e.g., on top of the heap during the heap leaching process); may include adding additional pyrite to the ROM material.

[0055] The term "intermediate station" is understood herein to include a fixed storage facility, such as a warehouse, or a mobile transport vehicle (e.g., a vehicle for transferring ROM material from truck to train) that receives ROM material at any time between the loading location and the heap.

[0056] Typically, ROM materials contain pyrite.

[0057] The total pyrite, i.e., the sum of the pyrite in the ROM material and the additional pyrite, may be 1 to 10 wt. %, typically 1 to 6 wt. %, more typically 1 to 5 wt. % of the total mass of the ROM material and the additional pyrite.

[0058] The additional pyrite may be obtained from any suitable source.

[0059] It should be noted that the additional pyrite may be present in any suitable form, but the important consideration is whether the pyrite is in a form that can react beneficially in the heap.

[0060] The pyrite may be in the form of a pyrite concentrate.

[0061] The method may include sourcing additional pyrite from the mine or another mine.

[0062] The method may include sourcing additional pyrite from tailings from the mine or another mine's tailings dam or material processing plant (such as cleaner scavenger tails from a concentrate circuit).

[0063] The method may include selecting an amount of pyrite added to be less than a threshold total pyrite concentration for the pyrite in the material and the additional pyrite.

[0064] The threshold total pyrite concentration may range from 1 to 10 wt. % of the sum of the ROM material and the additional pyrite, typically from 1 to 6 wt. %, and more typically from 1 to 5 wt. The selection of the threshold total pyrite concentration for a particular situation depends on various factors. For example, if the ROM material contains large amounts of secondary metal sulfides and is located in a warm / hot climate, the threshold total pyrite concentration may be at or near a lower limit of 1 wt. %.

[0065] In some cases, the ROM material contains enough pyrite that the addition of pyrite concentrate is not necessary.

[0066] For example, if the ROM material already contains the required threshold total pyrite concentration, it may not be necessary to add additional pyrite. However, even in this situation, additional pyrite may be added so that the target temperature can be reached more quickly than would otherwise be the case. This is especially true if the added pyrite has a fine particle size and is therefore easily reactable.

[0067] The additional material (additive) may be a microorganism for oxidizing ferrous ions and oxidizing solid and soluble sulfur compounds, thereby regenerating ferric ions and acid and generating heat.

[0068] The microorganism may be any suitable microorganism.

[0069] The microorganism is any microorganism capable of oxidizing ferrous iron and / or sulfur compounds, including, but not limited to, members of the bacterial genera Acidithiobacillus, Leptospirillum, Sulfobacillus, and Ferrimicrobium, and the archaeal genera Acidianus, Acidiplasma, Ferroplasma, Metallosphaera, and Thermoplasma.

[0070] Typically, the microorganisms are a diverse population and include microorganisms selected from mesophilic bacteria, moderate thermophiles, and psychrotolerant or mesophilic or thermophilic (moderate or extreme) bacteria or archaea. The microorganisms may be acidophilic bacteria or archaea. The microorganisms may be thermoacidophilic bacteria. The diverse population allows for activity under a variety of operating conditions, including low pH conditions, high sulfate concentrations, and a wide temperature range, e.g., from 5 to 80°C.

[0071] The method may include adding other additives (in addition to the microorganisms and pyrite described above) to the ROM material before, as, or after the heap is formed, or to the leachate, to enhance metal extraction from the heap.

[0072] When the metal is copper, other additives may include silver in the form of silver chloride, silver nitrate, or silver sulfate. As noted above, international applications PCT / AU2016 / 051024 (WO2017 / 070747) and PCT / AU2018 / 050316 (WO2018 / 184071) disclose the effect of increasing silver on the bioleaching of copper-containing mined materials.

[0073] When the metal is copper, the other additives may include an activator for activating silver selected from thiourea, chlorides, bromides, and iodides. As mentioned above, International Application PCT / AU2018 / 050316 (WO2018 / 184071) discloses an activator for activating silver, which facilitates the extraction of copper from copper-containing mined materials.

[0074] When the metal is copper, other additives may include complexing agents (such as thiourea and carbamide phosphate, as disclosed in U.S. Pat. No. 3,679,397, the entire disclosure of which is incorporated herein) that promote the dissolution of copper by forming a complex between (a) sulfur derived from copper minerals in copper-bearing mined materials, and (b) the complexing agent. As noted above, International Application PCT / AU2019 / 050383 (WO2019 / 213694) discloses the effect of such additives on the dissolution of copper from copper minerals in copper-bearing mined materials or from copper minerals in concentrates of such materials.

[0075] When the metal is copper, other additives may include chloride.

[0076] Other additives may be added to the heap in any suitable manner.

[0077] For example, the method is as follows: (a) Locations where ROM material is formed in mining operations (e.g., slump material formed after excavating and blasting a mine bench); (b) Where the ROM material is loaded onto a transport vehicle (such as a haul truck or load-dump vehicle), conveyor, or other means of transportation, additional pyrite is added either when the ROM material is loaded onto the means of transportation or after it has been loaded onto the means of transportation; (c) When ROM material is being transported from a loading point within a mine to a heap, stockpile, or intermediate station, or when ROM material is being transported from a stockpile or intermediate station to a heap; (d) When ROM material is being added to the heap, (e) At an intermediate station located between the loading area and the heap, (f) At an intermediate station located between the stockpile and the heap, (g) In a mixing operation involving mixing the ROM material with additional pyrite and then adding the mixture to the heap; (h) In stockpiles: (i) in the heap (e.g., in the leachate or directly as a separate additive when or after the heap is formed, e.g., on top of the heap during the heap leaching process); One or more of the above may include adding other additives to the ROM material.

[0078] If chloride is added, it is typically added to the leachate, typically in an amount such that the total chloride in the leachate is up to 10 g / l, suitably up to 4 g / l.

[0079] The term "total chloride" is the sum of the chloride already present in the leachate and any additional chloride added to the leachate.

[0080] The heap forming step (a) may include expanding an existing heap by adding ROM material and additional pyrite to form another vertical lift of the heap.

[0081] The heap forming step (a) may include expanding an existing heap by expanding the length or width of the heap.

[0082] The heap formation step (a) may include expanding an existing heap by adding a lift of new ROM material to the heap to increase the height of the heap.

[0083] The heap leaching step (b) may include supplying air to the heap via forced aeration.

[0084] The heap leaching step (b) may include supplying air to the heap via natural circulation of air from outside the heap into the heap.

[0085] The leachate may be any suitable acidic leachate.

[0086] By way of example, where metals such as copper are recovered from the pregnant leach solution in heap leaching step (b), the acidic leach solution may be a raffinate.

[0087] An example of a suitable acid is H2SO4.

[0088] When the metal is copper, the method may include controlling the acid concentration in the heap at an acid dosage rate of less than 100 kg H2SO4 / dry t material, typically less than 50 kg H2SO4 / dry t material, typically less than 30 kg H2SO4 / dry t material, or even less than 10 kg H2SO4 / dry t material, or even less than 5 kg H2SO4 / dry t material. Typically, the acid dosage rate is less than 1-30 kg H2SO4 / dry t material, more typically less than 1-20 kg H2SO4 / dry t material.

[0089] The method may include monitoring heap parameters selected from one or more of heap temperature, leachate irrigation rate (including any pause rinse cycle), aeration rate, leachate pH, leachate Eh, microbial population, copper extraction rate, etc., and adjusting one or more of the parameters to maintain target heap conditions.

[0090] The target heap conditions in a particular situation will be a function of several factors, including the mineralogical properties of the ROM material, climatic conditions, and the availability and cost of additives such as additional pyrite.

[0091] The metal may be any suitable metal that forms a soluble metal sulfate complex.

[0092] Examples of suitable metals include copper, nickel, zinc, and cobalt.

[0093] When the metal is copper, the metal sulfide-containing material may be a copper sulfide-containing material.

[0094] The copper sulfide-containing material may be any suitable copper sulfide-containing material, such as a copper sulfide mineral, such as chalcopyrite.

[0095] The ROM material may have any suitable copper grade, i.e., concentration of copper in the material.

[0096] By way of example, the ROM material may have an average copper concentration of 1.5 weight percent (wt%) or less, typically 1.2 wt% or less, and more typically 1.0 wt% or less.

[0097] The ROM material may have a low copper grade.

[0098] ROM material may have copper grades that are considered too low to be economically processed in flotation or other hydroprocessing systems to recover copper from the material or concentrates of the material.

[0099] The term "low grade" as used in connection with copper sulfide-containing materials is understood herein to be a term dependent on currently available technology and the current price of copper, and materials currently considered "low grade" may be considered valuable materials in the future, depending on technological developments and future copper prices. The term "low grade" has the same meaning as applied to nickel, zinc, and cobalt above.

[0100] More specifically, copper sulfide-containing materials may be present in ROM materials that are too low grade to be economically processed by conventional processing methods.

[0101] For purposes of context, the term "low copper concentration" is understood to mean an average copper concentration of 0.9 wt.% or less, typically 0.7 wt.% or less, typically 0.5 wt.% or less, more typically 0.3 wt.% or less, even more typically 0.2 wt.% or less, and even more typically 0.1 wt.% or less.

[0102] The ROM material can be of any size suitable for the heap leaching step (b).

[0103] For example, the ROM material may have rock sizes ranging from 200 mm P80 to 30 mm P80, typically ranging from 100 mm P80 to 50 mm P80.

[0104] It should be noted that the size of the ROM material may be larger or smaller than the size ranges listed above.

[0105] The ROM material can be in any suitable shape, but it should be noted that the size ranges described in the previous paragraph are based on only one dimension.

[0106] The method may include selecting a mining method to produce ROM material in a morphology (including size distribution and / or shape) suitable for the heap leaching process.

[0107] The mining method may include an open pit mining method for producing ROM material.

[0108] Open pit mining methods may involve excavating and blasting blocks of material, with the blasted rock falling into a pit as ROM material and transported from the pit by haul trucks or other suitable vehicles or conveyors.

[0109] The mining method may include an underground mining method that produces ROM material.

[0110] The underground mining method may include block caving mining, sublevel caving mining, or other suitable underground mining method. Material is removed from an extraction point, such as the extraction point of a block cave mine, as ROM material and transported to the surface by haul truck or other suitable vehicle or conveyor.

[0111] The mining method may include breaking down rocks of ROM material that are too large to transport from the mine into smaller rocks of ROM material, for example by a rock crusher, as described herein.

[0112] The mining method may include separating the ROM material based on size, for example through a screen, into different sized pieces, where the size-separated material falls within the definition of ROM material.

[0113] The present invention also provides a method for heap leaching copper from run-of-mine ("ROM") material from a mine containing copper sulfide-bearing material, the method comprising: (a) creating a heap of ROM material or expanding an existing heap by adding ROM material to the heap; (b) In the heap: i. Additional pyrite to the pyrite in the ROM material; ii. Silver; iii. An activator for activating the added or native silver in the ROM material; iv. a complexing agent for facilitating dissolution of copper sulfide in the ROM material by forming a complex between (a) sulfur from the copper sulfide-containing material in the ROM material and (b) the complexing agent; v. Chloride; adding one or more or all of the additional materials (additives) (c) leaching copper from the ROM material in the heap using an acidic leachate; The present invention provides a method comprising:

[0114] The present invention also provides a method for heap leaching copper from run-of-mine ("ROM") material from a mine containing copper sulfide-bearing material, the method comprising: (a) mining ROM material; (b) The ROM material includes: i. Additional pyrite to the pyrite in the ROM material; ii. Silver; iii. An activator for activating the added or native silver in the ROM material; iv. a complexing agent for facilitating dissolution of copper sulfide in the ROM material by forming a complex between (a) sulfur from the copper sulfide-containing material in the ROM material and (b) the complexing agent; v. Chloride; adding one or more or all of the additional materials (additives) (c) forming a heap of ROM material; (d) leaching copper from the ROM material in the heap using an acidic leachate; The present invention provides a method comprising:

[0115] Here's how: (a) Locations where ROM material is formed in mining operations (e.g., slump material formed after excavating and blasting a mine bench); (b) Where the ROM material is loaded onto a transport vehicle (such as a haul truck or load-dump vehicle), conveyor, or other means of transportation, additional pyrite is added either when the ROM material is loaded onto the means of transportation or after it has been loaded onto the means of transportation; (c) When ROM material is being transported from a loading point within a mine to a heap, stockpile, or intermediate station, or when ROM material is being transported from a stockpile or intermediate station to a heap; (d) When ROM material is being added to the heap, (e) At an intermediate station located between the loading area and the heap, (f) At an intermediate station located between the stockpile and the heap, (g) In a mixing operation involving mixing the ROM material with additional pyrite and then adding the mixture to the heap; (h) In stockpiles: (i) in the heap (e.g., in the leachate or directly as a separate additive when or after the heap is formed, e.g., on top of the heap during the heap leaching process); One or more of the above may include adding additional additives to the ROM material.

[0116] The present invention also provides a heap leaching operation for leaching metals from run-of-mine (ROM) material containing metal sulfide-containing material, such as metal sulfide minerals, in accordance with the heap leaching method described above, the heap leaching operation comprising: (a) said heap of ROM material and additional pyrite; (b) (i) supplying the heap with an acidic leach solution and microorganisms, the leach solution flowing downwardly through the heap to leach metals from the material, and (ii) recovering a pregnant leach solution from the heap containing the metals in solution, wherein the pyrite generates acid and heat within the heap to facilitate leaching of metals from the ROM material, and the microorganisms oxidize ferrous ions and oxidize solid and soluble sulfur compounds, thereby regenerating ferric ions and acid and generating heat. Includes.

[0117] Broadly, the present invention also provides a method for mining run-of-mine ("ROM") material and heap leaching the ROM material, the method comprising: (a) mining a material containing metal sulfide-containing material to form a ROM material; (b) The above heap leaching method and Includes.

[0118] The above heap leaching method, heap leaching operation, and mining method have the following advantages: Heap leaching of ROM material facilitates relatively rapid heap construction, thereby minimizing time delays to generating cash flow. This method makes it possible to extract metals such as copper, nickel, zinc or cobalt from metal sulfide-bearing materials that mining operators have previously classified as "uneconomical" from a metal recovery perspective. If additional pyrite is sourced from the mine (or another mine), for example from the mine's tailings treatment facility, this method will allow for the disposal of pyrite-containing tailings and reduce the capacity of existing tailings dams, which is an important environmental outcome. The acid-producing and heat-generating capabilities of pyrite (whether it is already present in the ROM material or as added pyrite) can be advantageous in heap leaching, for example, reducing the amount of added acid required in the leachate. Furthermore, the acid-generating capacity of pyrite means that any additional pyrite can be beneficially used in the leaching process, leading to a net reduction of pyrite, which is important from an environmental perspective. The method can be operated using readily available and proven equipment. This method allows for the processing of what would previously be classified as "waste" metal (e.g. copper) sulfide-containing materials, reducing the environmental impact of these materials and optimizing value recovery from ROM materials.

[0119] The invention will now be further described, by way of example only, with reference to the drawings in which: [Brief explanation of the drawings]

[0120] [Figure 1] 1 is a flowsheet illustrating one embodiment of a method for heap leaching copper sulfide-containing material in accordance with the present invention. [Figure 2] 1 is a flowsheet illustrating another embodiment of a method for heap leaching copper sulfide-containing material in accordance with the present invention. [Figure 3] 1 is a graph showing the results of experimental work related to a general method of heap leaching copper sulfide-containing material in accordance with the present invention. [Figure 4] 1 is a graph showing the results of experimental work related to a general method of heap leaching copper sulfide-containing material in accordance with the present invention. [Figure 5] 1 is a graph showing the results of experimental work related to a general method of heap leaching copper sulfide-containing material in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0121] The present invention is generally directed to recovering copper from copper sulfide-bearing materials formed in mining operations, specifically ROM materials containing copper sulfide minerals such as chalcopyrite.

[0122] As noted above, the term "mining operations" covers surface and underground mines that produce ROM material, which is then transported from the mine to downstream plants where it is processed to ultimately recover the copper.

[0123] It should be noted that the present invention is not limited to copper, but also applies to other metals such as nickel, zinc, or cobalt in metal sulfide-containing materials (such as metal sulfide minerals) in the material.

[0124] The embodiments of the invention described below in connection with Figures 1-5 are based on microbially assisted heap leaching of ROM material with selected additives (described below) for periods of up to 35-40 years. The invention is not limited to microbially assisted heap leaching or its duration.

[0125] Generally speaking, each of the embodiments shown in Figures 1 and 2 is a method of mining materials and recovering copper from copper sulfide minerals in ROM materials, comprising: (a) mining and optionally stockpiling ROM material containing copper sulfide minerals (e.g., chalcopyrite); (b) forming a heap of ROM material, or expanding an existing heap by adding ROM material, by forming a new lift, or by increasing the length and / or width dimensions of the existing heap (optionally adding pyrite concentrate or other suitable form of pyrite to the ROM material if additional pyrite is required in the ROM material (or additional pyrite in a form other than the pyrite contained in the ROM material)); (c) leaching copper from the ROM material in the heap using an acidic leachate and microorganisms; (d) optionally, adding one or more other additives (described below), such as silver, silver activators, complexing agents, chlorides, etc., to the ROM material before, during, or after heap formation, in addition to any added pyrite, to facilitate extraction of copper from the ROM material; (e) recovering pregnant leach solution from the heap, the pregnant leach solution containing copper in solution; (f) recovering copper from the pregnant leach solution via a solvent extraction system; (g) recovering the raffinate produced during the recovery of copper from the pregnant leach solution in the solvent extraction system and transferring it to the heap as leach solution; The method includes:

[0126] Typically, ROM materials have low copper grades of 0.9 wt% or less, typically 0.8 wt% or less, more typically 0.7 wt% or less, more typically 0.5 wt% or less, even more typically 0.3 wt% or less, and even more typically 0.1 wt% or less. The present invention also applies to ROM materials with higher copper concentrations.

[0127] Additionally, the embodiments of the methods for recovering copper from ROM materials containing copper sulfide-bearing materials (specifically copper sulfide minerals such as chalcopyrite) according to the present invention illustrated in Figures 1-5 are described in the context of the pyrite being a pyrite concentrate extracted from mine tailings. The present invention also applies to other forms of additional pyrite.

[0128] It will be understood that the present invention is not limited to these embodiments, but extends generally to any suitable copper-bearing material and any suitable source of pyrite.

[0129] Oxidizing agents and acids are required to extract copper from ROM materials containing copper sulfide minerals such as chalcopyrite.

[0130] In the following examples, ferric ions are used as the oxidizing agent and sulfuric acid is used as the acid. During the process of dissolving the minerals, the ferric ions are reduced to ferrous ions and the sulfuric acid is consumed during the reaction with the gangue minerals.

[0131] The microorganisms oxidize ferrous ions to regenerate ferric ions and oxidize solid and soluble sulfur compounds to produce sulfuric acid and heat.

[0132] To maintain sufficient iron and sulfur oxidation rates to promote optimal copper extraction, the microbial community must be provided with a habitable environment and the necessary nutrients.

[0133] The dissolution mechanism of copper sulfide minerals in ROM materials relies on the presence of ferric ions and acid to break down the mineral matrix and solubilize the metal. Ferric ions and acid are consumed during oxidation of the minerals, and if not replenished, the dissolution rate will decrease.

[0134] Under aerobic conditions, microorganisms (acidophilic bacteria and archaea, more specifically the bacterial genera Acidithiobacillus, Leptospirillum, and Sulfobacillus, and the archaeal genera Acidianus, Acidiplasma, Ferroplasma, Metallosphaera, Sulfolobaceae, and Thermoplasma) regenerate ferric ions and acid through the biological oxidation of ferrous ions (from pyrite FeS2 and chalcopyrite CuFeS2, for example) and sulfur compounds (including elemental sulfur), as follows: 2Fe 2+ +2H + +0.5O2 → 2Fe 3+ +H2O 2S+3O2+2H2O→2H2SO4

[0135] The sulfur compounds may be derived from the oxidation of sulfide minerals (such as pyrite) or may be provided as an additive (such as elemental sulfur) from any source, such as scavenging tailings from the concentration circuit. The sulfur compounds may be inorganic sulfur-containing compounds such as thiosulfates, polythionates, or polysulfides, or organic sulfur-containing compounds such as thiourea or other thiocarbamides.

[0136] These reactions not only maintain ferric ion and acid concentrations but also generate energy, making the process potentially autocatalytic under ideal conditions for microbial growth.

[0137] Changes in solution conditions during mineral dissolution of copper sulfide minerals in ROM materials affect the activity of microorganisms present within the leaching environment.

[0138] Applicants have discovered that the oxidation rates of ferrous ions and sulfur are affected by high metal concentrations, variations in solution pH, and temperature. If the iron ions and acids are not regenerated at a sufficient rate through microbial activity, dissolution of sulfide minerals (and therefore copper extraction from copper sulfide minerals in ROM materials) can be adversely affected.

[0139] <Embodiment 1> Figure 1 One embodiment of a method for heap leaching copper sulfide-containing ROM material in accordance with the present invention is described with reference to FIG.

[0140] The ROM material is formed during mining operations at a mine 1 , loaded onto haul trucks 2 (or other suitable vehicles) within the mine, and transported from the mine to a heap site to form a heap 5 .

[0141] The transportation of ROM material from mine 1 to the heap location may include one or more intermediate stops at stockpiles or transfer stations.

[0142] In some situations, ROM material may be stored in stockpiles or transfer stations for a significant period of time before finally arriving at a heap location.

[0143] The term "considerable period" is intended to include the period during which waste rock stockpiles are stored at the mine site until the waste rock can be economically processed to recover the metals, which may be measured in years, decades, or longer.

[0144] It should be noted that the present invention also applies to ROM material that has been subjected to rock crushing of larger rock pieces of the ROM material, and / or size separation of the ROM material into different sized fragments.

[0145] Screening of ROM material is one example of a size separation option.

[0146] In both cases where rock crushing and / or size separation has been performed, the resulting material falls within the definition of ROM material.

[0147] Heap5 may be a new heap that includes the ROM material used to construct heap5.

[0148] Heap 5 may be an existing heap that includes ROM material being used to form a new vertical lift or to extend the length and / or width dimensions of heap 5.

[0149] The heap can be of any suitable structure.

[0150] As an example, heap 5 may contain: (a) Leachate storage and delivery system 8 (which delivers leachate, essentially raffinate, to the upper surface of the heap, allowing the leachate to percolate into the heap and solubilize the copper in the heap); (b) an outer cover (not shown) (e.g., thermofilm, covering at least the sides of the heap to assist in temperature control within the heap); (c) an aeration system 7 (e.g., comprising a blower and piping for supplying air from the blower to the inside of the heap); (d) pregnant leachate collection system (not shown) (a system for collecting leachate containing copper in solution extracted from copper sulfide-bearing material in the heap); (e) Microorganisms and other suitable oxidizing agents (produced in microbial production unit 6 for oxidizing ferrous ions and oxidizing solid and soluble sulfur compounds, thereby regenerating ferric ions and acids and generating heat).

[0151] If additional pyrite is needed in addition to the pyrite already present in the ROM material, a predetermined amount of pyrite concentrate 3 (or other suitable form of pyrite) is added to the ROM material. Such addition of additional pyrite may occur where the ROM material is formed, where the ROM material is loaded onto haul truck 2 (or other suitable vehicle or transportation means, including a conveyor), as the ROM material is being transported from a loading location, at a stockpile or an intermediate station between the loading location and the heap, and / or where heap 5 is located (including on the heap). For example, pyrite concentrate 3 (or other suitable form of pyrite) can be added to haul truck 2 as the ROM material and / or heap 5 are being transported. The amount of pyrite concentrate 3 is determined, as needed, for a particular situation, including during heap leaching step (b), taking into consideration the range of (but not limited to) the following parameters: pyrite concentration in pyrite concentrate 3, amount of pyrite in the ROM material, mineralogy of the ROM material, target copper extraction rate, target heap temperature, target ramp-up time to target heap temperature, leaching conditions including Eh of the acid leachate and / or irrigation rate, type and population of microorganisms in the heap, and other additives 4 (described below) added to the ROM material at (including on) the heap 5, where the ROM material is formed, where the ROM material is loaded onto the haul truck 2 (or other suitable vehicle or transport means, including a conveyor), and when the ROM material is being transported from the loading location. Evaluation may include monitoring one or more of the aforementioned parameters.

[0152] A predetermined amount of the microbial population produced in the microbial production unit 6 is added to the ROM material in the transport truck 2, in the heap 5, or in the leachate of the heap 5, including during the heap leaching step (b). The microbial population required in a particular situation is determined by considering the parameters described in the previous paragraph. The selection of the location for adding the microorganisms can be determined by considering an evaluation of the operating conditions during the heap leaching of the ROM material. The evaluation can include monitoring one or more of the above parameters.

[0153] The microorganisms can be produced in any suitable microbial production unit 6. In one embodiment, the microbial production unit 6 comprises a series of connected stirred tanks. Air, acid, and water are supplied to the tanks as needed. In addition, iron-containing sulfide minerals (e.g., pyrite) in the tailings from a cleaning and scavenging unit of a concentration circuit (not shown) within the mine are supplied to the tanks. It should be noted that the iron-containing sulfide minerals (such as pyrite) can be obtained from any suitable source.

[0154] Optionally, one or more other additives to enhance extraction of copper from the ROM material, such as silver, a silver activator, a complexing agent (e.g., a salt such as chloride), collectively referred to in FIG. 1 as catalyst additives 4, may be added in predetermined amounts as described below.

[0155] A predetermined amount of silver 4 may be added to the ROM material, for example, in the form of silver chloride, silver nitrate, or silver sulfate. This is optional, as sufficient silver may be present in the ROM material. The location of the silver 4 addition can be determined by evaluating the operating conditions during the heap leaching of the ROM material. The evaluation may include monitoring one or more of the aforementioned parameters. As noted above, International Applications PCT / AU2016 / 051024 (WO2017 / 070747) and PCT / AU2018 / 050316 (WO2018 / 184071) disclose the effect of silver addition on the bioleaching of agglomerated copper-containing ROM material.

[0156] Additionally, a predetermined amount of an activator 4 (e.g., selected from thiourea, chloride, bromide, and iodide) for activating silver may be added to the ROM material. The location of the activator addition may be determined by evaluating the operating conditions during the heap leaching of the ROM material. The evaluation may include monitoring one or more of the aforementioned parameters. As noted above, International Application PCT / AU2018 / 050316 (WO2018 / 184071) discloses an activator for activating silver, which promotes copper extraction from the copper material.

[0157] Additionally, a predetermined amount of additive 4 (e.g., thiourea and carbamide phosphate, as disclosed in U.S. Pat. No. 3,679,397), which forms a complex between (a) sulfur derived from copper minerals in the material and (b) the additive, may be added to the ROM material in the transport truck 2, to the heap 5, or in the heap leachate, including during heap leaching step (b). The selection of the location for adding such additive may be determined in consideration of an evaluation of operating conditions during heap leaching of the ROM material, including monitoring one or more of the aforementioned parameters. As noted above, International Application PCT / AU2019 / 050383 (WO2019 / 213694) discloses the effect of such additives on the dissolution of copper from copper minerals in the material or from copper minerals in a concentrate of the material.

[0158] Additionally, a predetermined amount of additive 4 may be added to the ROM material in the form of chloride (or other salt). The selection of the location of chloride addition may be determined in light of an evaluation of the operating conditions during the heap leaching of the ROM material. The evaluation may include monitoring one or more of the aforementioned parameters. Typically, chloride is added to the leachate, which is essentially a raffinate. Typically, chloride is added to the leachate in an amount such that the total chloride in the leachate is up to 10 g / L, suitably up to 4 g / L. As noted above, the term "total chloride" refers to the chloride already present in the leachate plus any additional chloride added to the leachate.

[0159] A suitable acid, such as sulfuric acid, may be added to the ROM material in a predetermined amount. The location and dosage rate of the acid addition may be selected based on an evaluation of the operating conditions during the heap leaching of the ROM material. The evaluation may include monitoring one or more of the aforementioned parameters.

[0160] The additional microorganisms, silver, activators, sulfuric acid, and other additives mentioned above can be added to the ROM material where it is formed, where it is loaded onto the haul truck 2 (or other suitable vehicle or transport means, including a conveyor), when it is being transported from the loading location, where the heap 5 is present, including on the heap and in the heap leachate (the leachate is essentially the raffinate supplied from the leachate storage and supply system 8), and during the heap leaching step (b), including during the course of the heap leaching step (b).

[0161] The pregnant leach solution from heap 5 is processed in a solvent extraction system 9, which extracts copper from the pregnant leach solution in an organic medium (solvent) and then strips the copper from the organic medium to produce a copper-containing solution. The present invention applies to any suitable copper recovery system.

[0162] The copper-containing solution is transferred to an electrowinning plant 11 where copper is recovered from the solution.

[0163] The raffinate from the solvent extraction system 9 is regenerated and transferred to the leachate storage and delivery system 8 and returned to the heap as leachate. Make-up acid is also added to the leachate storage and delivery system 8 as needed.

[0164] The leachate regeneration system is provided with a raffinate bleed limestone / lime neutralizer 10 to control the buildup of impurities and produce neutralized solids that can be stored separately or co-stored with the tailings.

[0165] The pyrite-containing concentrate present in heap 5 provides a valuable source of (a) acid via the pyrite, and (b) heat within heap 5.

[0166] The acid generating properties of pyrite allow a reduction in the amount of acid that needs to be added to the leach solution to maintain a given leach acid demand.

[0167] As mentioned above, pyrite can be sourced from mine tailings.

[0168] This option is described in the aforementioned international applications PCT / US2021 / 043869 (WO2022 / 026810) and PCT / US2021 / 043869 (WO2022 / 026826), the disclosures of which are incorporated herein by cross-reference.

[0169] For example, pyrite may be present in tailings from a mine or another mine tailings dam or material processing plant (such as clean sweep tailings from a thickener circuit).

[0170] As a further example, pyrite can be obtained as a pyrite concentrate by removing pyrite from a pyrite-containing slurry from a mine tailings dam or material processing plant.

[0171] The pyrite removal process may include floating pyrite-containing particles in a pyrite-containing slurry to produce (i) an inert stream as one float output and (ii) a pyrite-containing material stream, such as a pyrite-containing concentrate stream, as another float output.

[0172] The pyrite removal step may include a size separation step, such as by a cyclone or other suitable classifier, prior to the flotation step described above, to separate larger particles from the pyrite-containing slurry and transfer the remaining pyrite-containing slurry to the flotation step.

[0173] The pyrite removal step may involve reducing the size of the larger particles in a size reduction circuit and returning the reduced size particles to the size separation step.

[0174] <Embodiment 2> Figure 2 The embodiment described in relation to Figure 2 is substantially the same as the embodiment described in relation to Figure 1, and the same reference numerals are used in both figures.

[0175] The only difference between these embodiments is that the embodiment of Figure 2 uses a conveyor system to transport the ROM material from mine 1 to heap 5 and a material stacking system (not shown) to distribute the ROM material onto heap 5. Otherwise, both embodiments are the same, as are other unit operations and processing steps.

[0176] The embodiment of Figure 2 is particularly suitable where the size range of ROM material from the mine 1 is not too large and can be transported by a conveyor system.

[0177] The use of a conveyor system provides the opportunity to add additives such as pyrite and other additives previously mentioned.

[0178] For example, additive addition stations may be provided along the length of the conveyor.

[0179] For example, additive addition stations can be provided at the entrance and / or exit ends of the conveyor.

[0180] Advantages of the embodiment shown in FIGS. 1 and 2 The above embodiments and advantages of the present invention generally include the following advantages: Heap leaching of ROM material facilitates relatively rapid heap construction, thereby minimizing time delays to generating cash flow. This method allows for economical extraction of metals such as copper, nickel, zinc, or cobalt from mined materials that miners would classify as "uneconomic." This is achieved by using the additives and microorganisms mentioned above to improve extraction and recovery rates, and by applying the method to minimally processed ROM materials, reducing OPEX. · This method allows for a reduction in OPEX by heap leaching ROM material instead of crushed and agglomerated material, thereby providing an opportunity to improve overall economics. If additional pyrite is sourced from the mine (or another mine), this method will allow for the disposal of pyrite-containing tailings, reducing the capacity of existing tailings dams, an important environmental outcome. The acid-producing and heat-generating capabilities of pyrite (whether it is already present in the ROM material or as added pyrite) can be advantageous in heap leaching, for example, reducing the amount of added acid required in the leachate. Furthermore, the acid-generating capacity of pyrite means that any additional pyrite can be beneficially used in the leaching process, leading to a net reduction of pyrite, which is important from an environmental perspective. The method can be operated using readily available and proven equipment. This method allows for the processing of what would previously be classified as "waste" materials, reducing the environmental impact of these materials and optimizing value recovery from mines.

[0181] <Heap leaching methodology> Figures 1 and 2 The above description of the embodiment shown in Figures 1 and 2 provides details of the unit operations in the embodiment and the methodology for operating the embodiment.

[0182] The feasibility of heap leaching ROM material delivered directly from the mine or via a stockpile has been established in the modeling work described below.

[0183] The results of the modeling work provide a basis for mine operators to establish target operating conditions for heap leaching operations in specific situations, and to establish operating procedures to quickly start up heap leaching operations and maintain heap operation throughout the life of the heap.

[0184] In connection with startup, the method may include selecting the amount of additional pyrite in the heap and the type of pyrite addition (e.g., selecting a fine-sized pyrite concentrate) to optimize heat generation in the heap.

[0185] In connection with start-up, the method may also include selecting the amounts and types of other additives in the heap.

[0186] The target heap conditions in a particular situation will be a function of several parameters, including the mineralogy of the material, climatic conditions, microorganisms, acid selection, choice of additives (such as additional pyrite, silver, silver activators, and the aforementioned complexing agents and chlorides), availability and cost, target copper extraction rate, and economic factors such as operating costs, including reagent costs.

[0187] After the heap reaches a target temperature (determined by considering selection of operating parameters such as microorganisms, material mineralogy, leachate, and other factors), the method includes monitoring one or more heap parameters selected from heap temperature, leach liquor irrigation rate, aeration rate, leachate pH, leachate Eh, microbial population, other additive selection and addition rate, copper extraction rate, etc., and adjusting one or more parameters to maintain the target heap conditions.

[0188] Changes in the mineralogy and size of ROM materials, as well as climate change, will inevitably require adjustment of heap parameters.

[0189] Necessary adjustments can be determined, for example, by operator judgment in light of a review of monitored parameters, and adjustments may be made, for example, by adjusting irrigation rates, aeration rates, addition rates of pyrite and other additives.

[0190] The necessary adjustments can be determined, for example, by automatic control to adjust the heap conditions to the set values set before the startup of the heap in consideration of the modeling work of the heap. Further, the adjustments may be made, for example, by adjusting the irrigation rate, the aeration rate, and the addition rates of pyrite and other additives.

[0191] The necessary adjustments can be determined, for example, by automatic control to optimize the heap conditions through directly referring to the model of the heap. Further, the adjustments may be made, for example, by adjusting the irrigation rate, the aeration rate, and the addition rates of pyrite and other additives.

[0192] [Modeling] <Modeling work> The applicant conducted numerical fluid dynamics (CFD) modeling work on a general heap of ROM material to evaluate the present invention. The applicant modeled a series of scenarios regarding the presence or absence of "additives" that the applicant considers important for heap leaching performance.

[0193] <General heap> The general heap was created by the applicant from the following information. - Published information - Information obtained by averaging multiple samples - The applicant's findings from the above research and development projects (including the findings reported in the above international application) <0了00710>- The applicant's findings from the CuPER model developed by the applicant - Standard / industry practice parameters

[0194] The applicant did not rely on the applicant's confidential information outside the scope of the research and development project.

[0195] The CuPER model used by the applicant is the applicant's confidential model.

[0196] <Assumptions of the CFD model> - A heap of about 45 Mtpa. - Located in the Atacama Desert. ○ Expected weather conditions for this location. - P80 is 40mm ROM material. - Multiple lifts. - Each lift has a lift height of 18m. - 7 lifts. - Stack a new lift every month (30 days) and let it leach for a year (360 days). - The lowest lift was subjected to leaching for a total of 7 years (2520 days). - Faster transition to each subsequent lift. - Heaps were constructed (physical features) and manipulated (additives such as pyrite) to maintain heap temperature. o For example, the sides of the heap were completely covered with thermofilm to minimize heat loss. - The mineralogy of the ROM material is constant. - The average CuT content of the samples was 0.41%, with 74% of the copper being chalcopyrite. - The average pyrite content of the samples was 2.64%. - Adequate amount of microorganisms.

[0197] <Scenario> The CFD modeling evaluated the following scenarios: - 1. Base case - No additives (no chlorides in solution due to host rock) - 2. Silver + Chloride - 0.25g Ag / kg Cu - 1g / L chloride - 3.Pyrite concentrate - 1% increase in pyrite concentrate - 4. Thiourea - 5. Pyrite concentrate + silver + chloride - 1% pyrite increase - 0.25 g Ag / kg Cu - 1g / L chloride

[0198] <CFDモデリングアプローチ> - The results shown in FIGS. 3 to 7 are the outputs of the CFD modeling for the above general heap. - The assumptions of the CFD model were obtained from the CuPER modeling conducted by the applicant. Specifically, the applicant relied on the following. - The CuPER modeling of the general materials leached for 7 years (corresponding to the bottom lift of the heap) was used as the input for the CFD model. - The CuPER results regarding the rate constant and chalcopyrite passivation were used as the input for the CFD model. - The scenarios were modeled as newly constructed and operated heaps.

[0199] <Comparison of Results between CFD Model and CuPER Model> - The leaching performance of the basic case is better in the CFD model than in the CuPER model. ○ This may be related to the temperature predicted by the CFD model. - The advantages of the additives calculated from the results of the CFD model are slightly lower than those calculated from the CuPER model. - The general trends of the CFD model and the CuPER model are the same. - The complementary use of the approaches using the two models has sufficient reliability.

[0200] <Results> FIGS. 3 to 5 - The modeling results shown in FIGS. 3 to 5 are those of Lift 1 (total leaching for 7 years). - The results in FIGS. 3 to 5 support the feasibility of the pyrite concentrate ROM heap.

[0201] <Discussion of Results in FIGS. 3 to 5> <FIG. 3> Relationship between Copper Extraction and Time - This graph focuses on the relationship between the total copper extraction rate and time. - In Scenario 5 (pyrite concentrate + silver + chloride), the copper extraction rate was the highest and increased rapidly to a high extraction rate. - There is a significant difference in copper extraction rates between Scenario 5 and Scenario 1 (base case), both in terms of actual extraction rate and rise time. For example, after 1000 days, the copper extraction rate for scenario 5 was 60%, while that for scenario 1 was only 35%. As a further example, after 2000 days, the copper extraction rate in scenario 5 was 60%, while the copper extraction rate in scenario 1 was only 40-45%. - Scenario 3 (pyrite concentrate) had the second highest copper extraction rate and quickly increased to a high extraction rate.

[0202] <Figure 4> Chalcopyrite extraction versus time - This graph focuses on the chalcopyrite extraction rate versus time. - The results are in close agreement with the plot of copper extraction rate versus time in Figure 3, indicating that heap leaching of ROM material is effective for the difficult-to-leach chalcopyrite mineral.

[0203] <Figure 5> Relationship between average temperature and time - This graph focuses on the average heap temperature versus time. - Scenario 5 (pyrite concentrate + silver + chloride) had the highest heap temperature and rapidly increased to high extraction rates. - Note: Scenarios 1 (basic) and 2 (silver + chloride) are plotted in the figure but are not clearly shown in the figure. This is because the three cold scenarios essentially overlap (i.e., scenarios 1 (basic), 2 (silver + chloride), and 4 (TU) overlap), and the two hot scenarios also overlap (i.e., scenarios 3 (pyrite concentrate) and 5 (pyrite concentrate + silver + chloride) also overlap).

[0204] Many variations may be made to the embodiments described in connection with Figures 1 and 2 without departing from the spirit and scope of the present invention.

[0205] By way of example, the embodiment described in relation to Figures 1 and 2 involves sourcing pyrite concentrate from mine tailings, as described in the aforementioned international applications PCT / US2021 / 043869 (WO2022 / 026810) and PCT / US2021 / 043869 (WO2022 / 026826), but the invention is not limited to this option and extends to the use of any suitable source of pyrite.

[0206] As a further example, although the embodiments described in relation to FIGS. 1-5 include the use of certain additives such as silver, the present invention is not limited to these additives and extends to any suitable additive.

Claims

1. 1. A method for heap leaching metals from run-of-mine ("ROM") material from a mine containing metal sulfide-bearing material, comprising: (a) creating a heap of ROM material or expanding an existing heap by adding ROM material to the heap; (b) a heap leaching process using an acidic leach solution to leach metals from ROM material in a heap, wherein pyrite already present in the ROM material generates acid and heat that facilitates leaching of the metals from the ROM material, producing a pregnant leach solution containing the metals in solution; A method comprising:

2. 10. The method of claim 1, wherein the ROM material is transported directly from the mine to the heap, or directly from the mine to a stockpile and then directly to the heap.

3. 3. The method of claim 1 or 2, further comprising the steps of collecting the pregnant leach solution from the heap and recovering metals from the pregnant leach solution.

4. 4. The method of any one of claims 1 to 3, comprising adding an additional material (additive) to the ROM material before, as or after the heap is formed, or to the leachate.

5. 5. The method of claim 4, wherein the additional material (additive) comprises pyrite.

6. 6. The method of claim 5, comprising selecting the amount of additional pyrite so that the heap reaches the target temperature quickly, i.e., in 500 days or less, more typically in 400 days or less, more typically in 300 days or less.

7. 7. The method of claim 5 or 6, wherein the target temperature, expressed as the average heap temperature, is in the range of 60 to 80°C.

8. 8. The method according to any one of claims 5 to 7, wherein the additional pyrite and the pyrite in the ROM material, i.e. the total pyrite, is 1 to 10% by weight of the total mass of the ROM material and the additional pyrite.

9. 9. The method of any one of claims 5 to 8, wherein the additional pyrite is a pyrite concentrate.

10. 10. The method of any one of claims 5 to 9, comprising sourcing additional pyrite from the mine or another mine.

11. 11. The method of claim 9 or 10, comprising sourcing the additional pyrite from tailings from the mine or another mine's tailings dam or material processing plant (such as clean sweep tailings from a thickener circuit).

12. 12. The method of any one of claims 5 to 11, comprising selecting the amount of additional pyrite to be less than a threshold total pyrite concentration for the pyrite in the ROM material and the additional pyrite.

13. 13. The method according to any one of claims 4 to 12, wherein the additional material (additive) comprises microorganisms for oxidizing ferrous ions and oxidizing solid and soluble sulfur compounds, thereby regenerating ferric ions and acid and generating heat.

14. 14. The method of claim 13, wherein when the metal is copper, the additional material (additive) comprises silver.

15. 15. The method of claim 13 or 14, wherein when the metal is copper, the additional material (additive) comprises an activator for activating silver in the ROM material or an activator added to the ROM material.

16. 16. The method of claim 14 or 15, wherein when the metal is copper, the additional material (additive) comprises a complexing agent to promote dissolution of copper by forming a complex between (a) sulfur derived from copper minerals in the ROM material, and (b) the complexing agent.

17. The method of any one of claims 13 to 16, wherein when the metal is copper, the additional material (additive) comprises a chloride.

18. 18. The method of claim 17, wherein chloride is added to the leachate, typically in an amount to provide a maximum of 10 g / l of total chloride in the leachate.

19. 19. The method according to any one of claims 4 to 18, comprising: (a) Locations where ROM material is formed in mining operations (e.g., slump material formed after excavating and blasting a mine bench); (b) Where the ROM material is loaded onto a transport vehicle (such as a haul truck or load dump vehicle), conveyor, or other means of transport (additional material is added as the ROM material is loaded onto the means of transport or after it has been loaded onto the means of transport); (c) When ROM material is being transported from a loading point within a mine to a heap, stockpile, or intermediate station, or when ROM material is being transported from a stockpile or intermediate station to a heap; (d) When ROM material is being added to the heap, (e) at an intermediate station located between the loading area and the heap; (f) at an intermediate station located between the loading area and the stockpile; (g) at an intermediate station located between the stockpile and the heap; (h) In a mixing operation that includes mixing the ROM material with additional material and then adding the mixture to the heap, (i) In the stockpile: (j) in the heap (e.g., in the leachate or directly as a separate additive during or after the heap is formed, e.g., on top of the heap during the heap leaching process); 3. The method of claim 1, further comprising adding an additional material (additive) to the ROM material.

20. 20. The method of any one of claims 1 to 19, wherein the heap forming step (a) comprises expanding an existing heap by expanding the length or width of the heap.

21. 21. The method of any one of claims 1 to 20, wherein the heap leaching step (b) comprises supplying air to the heap via forced aeration.

22. 22. The method of any one of claims 1 to 21, wherein the heap leaching step (b) comprises supplying air to the heap via natural circulation of air from outside the heap into the heap.

23. 23. The method of any one of claims 1 to 22, comprising monitoring heap parameters selected from one or more of heap temperature, leach solution temperature, leachate irrigation rate (including any pause rinse cycles), aeration rate, leach solution pH, leachate Eh, microbial population, copper extractability, and adjusting one or more of the parameters to maintain target heap conditions.

24. The method of any one of claims 1 to 23, wherein the metal comprises any one of copper, nickel, zinc, and cobalt.

25. 25. The method of claim 24, wherein when the metal is copper, the metal sulfide-containing material comprises a copper sulfide-containing material such as a copper sulfide mineral such as chalcopyrite.

26. 26. The method of claim 25, wherein the ROM material has an average copper concentration of 1.5 weight percent (wt%) or less, typically 1.2 wt% or less, more typically 1.0 wt% or less.

27. 27. A method according to any preceding claim, wherein the rock size of the ROM material is in the range P80 200mm to P80 30mm, typically in the range P80 100mm to P80 50mm.

28. 28. A method according to any preceding claim, comprising selecting a mining method to form ROM material in a morphology (including size distribution and / or shape) suitable for a heap leaching process.

29. 1. A method for heap leaching copper from ROM material from a mine containing copper sulfide-bearing material, comprising: (a) creating a heap of ROM material or expanding an existing heap by adding ROM material to the heap; (b) In the heap: i. Additional pyrite to that in the ROM material; ii. silver; iii. an activator for activating the added or native silver in the ROM material; iv. a complexing agent for facilitating dissolution of copper sulfide in the ROM material by forming a complex between (a) sulfur from the copper sulfide-containing material in the ROM material and (b) the complexing agent; v. chloride; adding one or more or all of the additional materials (additives) (c) leaching copper from the ROM material in the heap using an acidic leach solution; A method comprising:

30. 1. A method for heap leaching copper from run-of-mine ("ROM") material from a mine containing copper sulfide-bearing material, comprising: (a) mining ROM material; (b) the ROM material comprises: i. Additional pyrite to that in the ROM material; ii. silver; iii. an activator for activating the added or native silver in the ROM material; iv. a complexing agent for facilitating dissolution of copper sulfide in the ROM material by forming a complex between (a) sulfur from the copper sulfide-containing material in the ROM material and (b) the complexing agent; v. chloride; adding one or more or all of the additional materials (additives) (c) forming a heap of ROM material; (d) leaching copper from the ROM material in the heap with an acidic leach solution; A method comprising:

31. 28. The method of claim 27, comprising: (a) Locations where ROM material is formed in mining operations (e.g., slump material formed after excavating and blasting a mine bench); (b) Where the ROM material is loaded onto a transport vehicle (such as a haul truck or load dump vehicle), conveyor, or other means of transport (additional material is added as the ROM material is loaded onto the means of transport or after it has been loaded onto the means of transport); (c) When ROM material is being transported from a loading point within a mine to a heap, stockpile, or intermediate station, or when ROM material is being transported from a stockpile or intermediate station to a heap; (d) When ROM material is being added to the heap, (e) at an intermediate station located between the loading area and the heap; (f) at an intermediate station located between the loading area and the stockpile; (g) at an intermediate station located between the stockpile and the heap; (h) In a mixing operation that includes mixing the ROM material with additional material and then adding the mixture to the heap, (i) In the stockpile: (j) in the heap (e.g., in the leachate or directly as a separate additive during or after the heap is formed, e.g., on top of the heap during the heap leaching process); 3. The method of claim 1, further comprising adding an additional additive to the ROM material.

32. A heap leaching operation for leaching metals from a ROM material containing metal sulfide-containing material according to the heap leaching method of any one of claims 1 to 31, the heap leaching operation comprising: (a) the heap of ROM material and additional pyrite; (b) (i) supplying the heap with an acidic leach solution and microorganisms, the leach solution flowing downwardly through the heap to leach metals from the material, and (ii) recovering a pregnant leach solution from the heap containing the metals in solution, wherein the pyrite generates acid and heat within the heap to facilitate leaching of metals from the ROM material, and the microorganisms oxidize ferrous iron to ferric iron. Heap leaching operations, including:

33. (a) mining ROM material containing metal sulfide-containing material; (b) a heap leaching method according to any one of claims 1 to 32; and 1. A method of mining ROM material and heap leaching the material, comprising:

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