AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant (s): BHP BILLITON INNOVATION PTY LTD Invention Title: PROCESS FOR THE GENERATION OF MICROORGANISMS FOR HEAP OR DUMP LEACHING The following statement is a full description of this invention, including the best method for performing it known to me/us: P74737AUJ-1 PaL.SjFIltg Aspil4UIn 2M-I-7.0c q -2 PROCESS FOR THE GENERATION OF MICROORGANISMS FOR HEAP OR DUMP LEACHING The present invention relates to a novel process 5 for generating a high concentration of microorganisms that can be used in a heap or dump leaching process, particularly in a bioleaching process. The term "heap" as used herein is understood to 10 describe material that has been crushed and agglomerated and stacked mechanically in a pile. The term "dump" as used herein is understood to describe material, such as run-of-mine material, that has been directly discharged into a pile without any prior processing. 15 The term "gas" as used herein is understood to mean atmospheric air with or without modification of the gas composition, air containing increased levels or amounts of oxygen and/or carbon dioxide, as well as 20 oxygen, carbon dioxide, and mixtures of each. The present invention is described in the context of leaching copper-bearing sulfide minerals to recover copper and, more particularly in the context of bioleaching copper bearing sulfide minerals. The present invention, 25 however, is not limited to leaching this material and to recovering this metal and extends to leaching any material in a heap/dump. Bioleaching is growing in importance for the 30 production of copper because of the need for environmentally friendly technology that is simple to implement and offers both considerable capital and/or operating cost savings. In this process, a bacterial inoculum (by which is meant a single microorganism or a 35 plurality of microorganisms) is typically produced in a temperature-controlled tank reactor to achieve the desired concentration of inoculum, on the order of 105 to 109 or N~ebun\ae~lni4D709W43.U1 0l\espoSpecuicndonadooDurn iWB -3 more cells/ml. The inoculum is then applied to a heap that has been formed from the material to be leached. In general, this process requires an external source of temperature, nutrients and ore, iron, and/or sulfur such 5 as provided by tailings, old heaps, concentrate, waste or other mineral sources containing sulfur and iron (e.g. pyrite). In addition, while it is known to use particular 10 microorganisms such as Thiobaciflus Ferrooxidans; Thiobacillus Thiooidans, Thlobacillus Organoparus; Thiobacillus AcIdphilus; Su~lfbacillus Threzoeulfidooxidans; AcIdanus Brierley; and Leptospirilltum Ferrooxidans, it is thought that the 15 bioleaching process may be enhanced if the microorganisms native or indigenous to the ore being leached could be propagated and then used in the heap or dump leaching process. 20 PCT W001/44519 and rcT w002/070757 describe the use of an ore heap and an inert rock heap where the inert rock heap is inoculated with a ferrous iron oxidizing bacteria. A leach solution pond is provided to collect the leach solution from both heaps where the leach 25 solutions are mixed. An alternative is described where a single leach solution pond is provided for each of the ore heap and the inert rock heap. Liquor from the ore heap pond is fed to the inert rock heap and the overflow from the inert rock pond is fed to the ore heap pond. 30 US 6,086,656 describes a heap leach process where a bioleachate solution is supplied from a tank to a first heap and the bioleachate off solution is applied to a second heap that is in a more advanced stage of bicoxidation compared to the first heap. The bioleachate 35 solution from the second heap may be applied to the first heap. N:%delbumen se palenl74D-749974737 AU,MpscisCompIele Spectelmnmdae 07111108 - 4 None of the above processes, however, contemplate propagating and collecting indigenous microorganisms in an inoculant pond that is separate from a pond that collects the heap leachate such that the heap leachate solution 5 does not enter the inoculant pond. Briefly, the process of the present invention generates an inoculum for a heap or dump leach process by forming at least one inoculant heap and at least one 10 operating heap. A portion of the inoculant heap and a portion of the operating heap may be in physical contact. The inoculant heap may be new ore and/or residue from leached ore. A leach solution (from any source) is applied to a top portion of the inoculant heap and allowed 15 to flow downward creating a pregnant solution which contains microorganisms which have been preferentially grown based on the operating conditions of the heap. The microorganisms are generally indigenous microorganisms. The pregnant solution is collected in an inoculant pond, 20 the conditions of which are controlled to propagate a desired inoculum. The propagated inoculum within the pond can then be recycled to the inoculant heap to further propagate or delivered to other areas of the plant operation. For example, the propagated inoculum can be 25 delivered to the operating heap, to the ore feed to the heap (e.g., after the are has been agglomerated), to the leach solution feed, to the working heap pregnant solution. 30 Advantageously, the process of the present invention can be used to generate both new and native inoculum. In addition, the process does not require an external source of food since the inoculant heap is used as the source of food for the inoculum. The process is 35 also flexible in that any part of the heap (new ore or leached ore) can be designated and defined to produce any desired inoculum so that there is no delay caused by ne n o7 pSpeeecadon.doe 0/11110B waiting for adaptation of an inoculum to the commercial plant conditions since such commercial plant conditions are used in the inoculant of the heap. 5 FIG. 1 is a schematic illustration of a process for generating an inoculum according to the present invention for use in a heap or dump leach process. The present invention relates to the generation of microorganisms for use in a dump or heap leaching process. 10 Turning now to Fig. 1, a schematic illustration of one embodiment of the process of the present invention is shown. In general, the process includes forming at least one inoculant heap 20 and forming at least one operating heap 50. As shown in Fig. 1, a single heap 10 is shown 15 with a portion of the inoculant heap 20 in physical contact with a portion of the operating heap 50 such that for all practical purposes a single heap 10 is created with a portion being defined as the inoculant heap 20 and with the remaining portion being defined as the operating 20 heap 50. While each heap 20, 50 are defined as being separate, in practice, each may have a portion that is in physical contact with another heap. The inoculant heap 20 is contacted with a leach 25 solution 22 that flows through the inoculant heap 20 to generate an inoculant pregnant leach solution 24 that is collected in an inoculant pond 26. The leach solution 22 may contain microorganism that are native or indigenous to the material being leached. Alternatively, the leach 30 solution 22 may contain microorganisms that are known to be useful for the bioleaching of the material in the inoculants heap 20. Importantly, each of the inoculant pond 20 and the operating heap pond 58 are separate. The conditions of the inoculant heap 20 and/or inoculant pond 35 26 are controlled to propagate a desired inoculum. The inoculum contained in the inoculants pond 20 can be directed to various parts of the operating process such as NAelo9 wweoesoatenc74000.74999\P74737.Alk1\SpcciB\Complet Sp*cng dac 0711/DS recycled to the inoculant heap 20, directed to the process leach solution 52 for the operating heap 50, directed to the ore 54 being delivered to the operating heap (such as in an agglomerating process), directed to the operating 5 heap pregnant solution pond 58 or other desired process areas. The contents of the operating heap pregnant solution pond 58 are not directed to the inoculant heap pond 26. Put another way, the only inflow to the inoculant pond 26 is from inoculant heap 20. 10 The operating heap 50 may be contacted with a leach solution 52 that contains the inoculum 40 derived from the inoculant heap 20. The leach solution 52 is allowed to flow through the operating heap 50 to generate 15 an operating heap pregnant solution 56 that is collected in an operating pond 50 that is physically separate from the inoculant pond 26. Moreover, the contents of the operating heap pond 58 are not directed to either the inoculant heap 20 or the inoculant pond 26. A portion of 20 the operating heap pregnant solution 56 may be directed to a metal recovery process 62. The heaps 20, 50 may be formed using any of the techniques known in the art for producing heaps for 25 leaching. The heaps may be constructed by stacking run of-the-mine ore to form the heaps. Alternatively, the ore may be crushed to a convenient particle size. The crushed ore may be agglomerated prior to stacking to improve gas and liquid flow within the heaps. 30 While the heaps 20, 50 can be constructed using coarse ore particles as support, other materials may also be used as support. For example, the coarse support material may be selected from the group consisting of 35 rock, brick, slag, and plastic. The coarse support may also include coarse ceramic particles. If the support ore is rock, as those skilled in the art will appreciate, a N;'oMbw e casemaweM174o74ew74nAU.1tpea.., te peeiraIgiorutcrOV -7 variety of rocks can be used for the coarse support, including lava rock, barren rock, and crushed copper ore. An advantage of using coarse chalcopyrite or 5 other copper sulfide ore particles as the support material is that the copper sulfides contained within this support material can be at least partially biooxidized during the process. Furthermore, the coarse support material can be recycled a number of times through the process thereby 10 resulting in even higher recoveries of copper from the coarse support. In addition, after the coarse ore support is processed through the process one or more times, it can be ground and the remaining sulfide minerals contained therein separated using known techniques in the art to 15 form a sulfide mineral concentrate. This concentrate can then be combined for coating on coarse ore support material and processing according to the invention. As noted above, in practice, the inoculant heap 20 20 and the operating heap 50 may be in physical contact with each other at least along one side (if the heap is constructed as a rectangle) so that it appears that only a single heap 10 is present. It is contemplated, however, that the inoculant heap 20 and the operating heap 50 be 25 physically separate heaps. Importantly, an inoculant pond 26 that receives a pregnant leach solution 24 from the inoculant heap 20 is provided physically separately from an operating pond 58 that receives a pregnant leach solution 56 from the operating heap 50. 30 While a single pond 26, 58 is described and shown for each of the inoculant pond 26 and the operating heap pond 58, respectively, it should be appreciated and understood that, in practice, more than a single pond for 35 each of the inoculant pond 26 and the operating heap pond 58 may be used. In this regard, however, each pond 26, 58 will function and will be physically separated in the same N! Ipnwlenlwaion449eer,7a7AUsspecieicompie 4peekv[lemdocOr11o manner as the single pond 26, 58 being described in the specification The leach solution for one of the inoculant heap, 5 the operating heap, or both may be pumped to the top of the respective heap through a respective process leach solution supply line. The leach solution 22, 52 may contain sulfuric acid and iron in ferric and/or ferrous form and may also contain nutrients. In general, however, 10 the nutrients necessary for the microorganisms to grow and metabolize the sulfide minerals in the inoculant heap 20 are present within the ore. Generally, the leach solution 22 for the 15 inoculant heap 20 will be pumped through a leach solution line t1at is different from the leach solution line for the operating heap 50. In either case, the leach solution 22, 52 can then be distributed over the top of the heap 20, 50 through leach solution distributors such as a 20 nozzle or any other known distributor such as pressure emitters, bagdad wigglers, sprinklers, wobblers, and flooding. The portion of the supply line that runs along the toi of the heap may be buried to further reduce evaporation and improve the insulation of the supply line 25 in situations where the process leach solution may be heated or cooled. A gas distributor may be positioned in either of the heaps to supply gas to the respective heap. A suitable example of a gas distributor is shown and descrii ed in US Published Application 2005/0048907. 30 As noted above, the inoculant pond 26 is physical ly separate from the operating pond 58. The inoculant pond 26 collects the pregnant leach solution 24 from thr inoculant heap 20 but not the pregnant leach 35 solution 56 from the operating heap 50. The contents of the ino'Iulant pond 26 may be recirculated 28 to the inoculant heap 20 or may be directed to other process N.-webounrn casepnhr4oq74eooUp47AUlpdCrpjm Spegiuaeasoo 0711 11M$ -9 locations related to the operating heap, as will be explained below. Advantageously, because the inoculant heap 20 and pond 26 are operated separately from the operating heap 50, the operation of the inoculant heap 20 5 can be operated in a variety of modes such as a start-up mode, an on-off mode, a continuous mode and the like. Notwithstanding this feature, it may be desirable to operate the inoculant heap 20 in a manner that is the same as or similar to the operating heap 50 so that the 10 propagated inoculum is adapted to the operating conditions of the operating heap 50. The conditions of the inoculant pond 26 are controlled using a controller 70 that receives inputs from 15 analysers and/or analyses (not shown) and provides outputs to control certain operating parameters of the inoculant pond 26. For example, certain operating parameters associated with the contents of the inoculant pond 26 are measured, compared with desired parameters, and then the 20 controller 70 provides an output to modulate one or more conditions associated with the desired parameters. For example, the temperature of the contents of the inoculant pond 26 may be measured in a known manner and compared to a desired temperature. If the measured temperature 25 differs from the desired temperature, the contents of the pond may be heated or cooled as required. Other parameters may include the dissolved oxygen content, the dissolved carbon dioxide content, the level of nutrients in the pond, the pH in the pond, and the like. It will be 30 appreciated that by controlling the operating parameters of the inoculant pond 26, a desired inoculum may be propagated. For example, under certain operating temperatures 35 (and possibly other operating conditions) mesophile microorganisms may be propagated. These microorganisms may, for example, be selected from the following genus N:W ucutmoeCase rstallI7400D-7499\P74737.AUispris\Complat SpeAelfmn~dgc 7/11l - 10 groups Acidithiobacillus (formerly Thiobacillus); Leptospirillum; Ferromicrobium; and Acidiphilium. These microorganisms may, for example, be selected from the following species AcidIthlobacilluS caldus (Thlobaoilu* 5 caldus); AcIdithiobacillus thiooxidans ( Thibaci2lus thiooxidans) ; AcIdithlobacllus ferrooxidana ( TMobacillnu terrooxidans) ; Acidithiobacillus acidophilus (Thibacillus acidophilus) ; Thiobacillus prosperous; Leptospirillum ferrooxidans; Ferromi crobium acidophilus; and Acidiphlium 10 cryptum. Alternatively, under different certain operating temperatures (and possibly other operating conditions) moderate thermophile microorganisms may be propagated. 15 These microorganisms may, for example, be selected from the following genus groups Acidithiobacillus (formerly Thiobacillus); Acidimicrobium; Sulfobacillus; Ferroplasma (Ferriplasma) ; and Alicyclobacillus. Suitable moderate thermophile microorganisms may, for example, he selected 20 from the following species Acidithiobacillus caldus (formerly Thiobacillus caldu); Acidimicrobium ferrooxidans; Sulfobacillus acidophiluu; Sulfobaclilus disulfIdooxidans; Sulfobacillus thermosulfidooxIdans; Ferropiasma acidazmanus; Thezmoplasma acidophilum; and 25 Alicyclobacillus acidocaldriuu, Additionally, under yet other different certain operating temperatures (and possibly other operating conditions) thermophilic microorganisms may be propagated. 30 These microorganisms may, for example, be selected from the following genus groups Acidothermus; Sulfolobus; Metallosphaera; Acidianus; Ferroplasma (Ferriplasma); Thermoplasma; and Picrophilus. Suitable thermophilic microorganisms may, for example, be selected from the 35 following species Sulfolobus metallicus; Sulfolobus acldocaldarlus; Sulfol obus thezmosuifidooxidans ; AcIdianus Infernus; Me tallosphaera sedula; Perroplasma acidarmanus; N:\Melbaump ses\Pmfrw74000-74999Mo3AU.1%Speals oplete Speicalin.doc 0",11JOB - 11 Thexmoplasma acidophilum; Thenzmoplasma volcanium; and Picrophilus ouhimas. It will also be appreciated that according to the 5 present invention the inoculant heap 20 may naturally select for microorganisms that are best able to bioleach the particular ore composition at that location and at the selected operating conditions. As a result, because a large amount of ore and rock that is used to build each 10 heap (inoculant and operating) will also contain native microbes, the process according to the present invention will also automatically select the native microorganisms that have enzymes, as well as other native microorganisms, that are able to bioleach the ore at the selected 15 operating conditions. Furthermore, because the solutions, the ore, and/or the support rock are likely to contain microbes that have not been previously isolated or that cannot be maintained in a laboratory culture by existing technology, the inoculant heap will become a source of 20 microbes that are not currently available from any known culture collections. As a result, the process of the present invention will provide an excellent source of microorganisms for use as an inoculum for the operating heap 50 as well as other heaps in that general location. 25 As noted above, the contents of the inoculant pond 26 may be recirculated 28 to the inoculant heap 20 to further propagate the desired inoculum. Generally, the retention time of the inoculum in the inoculant pond 26 is 30 sufficient for the microorganisms to multiply such that a significant population of microorganisms is always present, typically in the order of 105 to 10 cells per millilitre of solution. 35 In addition or alternatively, the contents of the inoculant pond 26 may be fed 40 to the leach solution line 52 for the operating heap 50, may be fed 42 to the ore N:WleImndro c Pmat74000-74n9?4737AU.,1wpecisComples Specificadoeo7h=100 - 12 forming the heap 54 (either to be used in agglomerating the ore or applied to previously agglomerated ore), may be fed 44 to the operating heap pond 58, may be fed to the operating heap pond recirculating line 60 to the operating 5 heap 50 (not shown) , may he fed 46 directly to the operating heap 50, or may be fed to any other operating process point. in this regard, the inoculum may be separated from the other contents of the inoculant pond 26 and fed to the process points described above. 10 Many modifications may be made to the embodiments of the present invention described above without departing from the spirit and scope of the invention. NWebaumelCa iPeI7400-7499%P747.7AU S pedsi o thendev 07111M0