AU2007284003A1

AU2007284003A1 - Collectors and flotation methods

Info

Publication number: AU2007284003A1
Application number: AU2007284003A
Authority: AU
Inventors: Graeme Philip Sheldon; Alexander Bradstock Tall
Original assignee: AB Tall Holdings Pty Ltd
Current assignee: AB Tall Holdings Pty Ltd
Priority date: 2006-08-17
Filing date: 2007-08-17
Publication date: 2008-02-21
Anticipated expiration: 2027-08-17
Also published as: WO2008019451A1; AU2007284003B2

Description

WO 2008/019451 PCT/AU2007/001175 COLLECTORS AND FLOTATION METHODS FIELD OF THE INVENTION 5 The present invention relates to reagents or combinations of reagents and/or reactions of reagents for use as collectors in mining operations to improve the yield of metal values and/or minerals recovered from a wide range of materials including ores, mineral pulps, slags, 10 tailings, waste materials and similar, and to methods of using the reagents in metal and mineral recovery processes. In one aspect the present invention relates to reagents 15 and combinations of reagents and/or reaction(s) of reagents and/or the product(s) of the reaction(s) of reagents which are used as collectors for increasing the recovery of selected metals and/or minerals from the materials being treated, particularly ores, mineral pulps 20 and slags, so that greater amounts of the selected metal(s) and/or mineral(s) are recovered from the material being treated along with lesser amounts of unwanted materials, such as contaminating and/or competing materials, particularly lesser amounts of gangue or waste 25 materials or other materials competing with the selected metal and/or mineral for recovery from the materials being treated. In one embodiment, the present invention relates generally 30 to improved collectors comprising mixtures and/or reaction(s) and/or product(s) of reaction(s) of reagents containing two or more different reagents in which the collectors have enhanced properties in froth flotation operations, including both selective flotation operations 35 and bulk flotation operations, to concentrate metal values WO 2008/019451 PCT/AU2007/001175 -2 from ores or mineral pulps or slags to allow the extraction of greater amounts of selected or desired metal values and/or minerals from the ores, mineral pulps, slags or similar during the flotation processes and to methods 5 of using the improved mixtures and/or reactions and/or reaction products having enhanced collector properties to increase the yield of recovered metals and/or minerals and/or to increase the grade of the metal or mineral recovered in the froth flotation process by substantially 10 rejecting gangue and/or waste materials and/or other competing materials, particularly rejecting the recovery of competing materials. In other embodiments, the present invention relates to new 15 and improved reagents comprising mixtures and/or reaction(s) of and/or products of reaction(s) of thionocarbamate(s) with other thionocarbamate(s), mixtures and/or reactions of dithiophosphate(s) with other dithiophosphate(s), mixtures and/or reactions of 20 mercaptobenzothiazole(s) with other mercpatobenzothiazole(s) and mixtures and/or reactions and/or product(s) of reaction(s) of two or more of such single, mixed and/or reacted thionocarbamate(s), dithiophosphate(s) and/or mercaptobenzothiazole(s) with 25 one another and with each other in different combinations, for use as improved collectors in recovering desired mineral(s) and/or metal values from ores, pulps, slags or similar in greater amounts and/or in greater concentrations, and/or having improved grades of recovered 30 material in the resultant concentrate. Although the present invention will be described with particular reference to specific mixtures and/or reactions WO 2008/019451 PCT/AU2007/001175 -3 and/or product(s) of the reaction(s) of specific reagents useful as collectors for selected mineral(s) and/or metal(s), it is to be noted that the scope of the present invention is not restricted to the described embodiments 5 of mixtures and/or reactions and/or product(s) of the reaction(s) but rather the scope of the present invention is broader so as to encompass other combinations of mixtures and/or reactions and/or product(s) of reaction(s) of reagents useful as collectors either with themselves, 10 with other examples of the same type of collectors or with other types of collectors, the use of the various mixtures of reagents to extract other minerals and/or metals, and the use of the reagents in applications and installations other than the recovery methods described. 15 BACKGROUND OF THE INVENTION Froth flotation is one of the most important and versatile mineral processing techniques in use in mining operations 20 to recover metal values generally from suitable materials, including ores and/or mineral pulps. Froth flotation is a widely used method of concentrating ores and is believed to be the most commonly used concentrating process in the mining industry. Not only is froth flotation used to 25 extract greater amounts of metal values generally but, more importantly, froth flotation is a selective process that can be used to achieve selective separation of a desired metal or small select range of desired metals from complex ores or mineral pulps containing different metal 30 values or a range of different metals, such as for example using bulk flotation processes, particularly competing metals, so that increased amounts of the selected minerals or metals can be recovered from the materials being WO 2008/019451 PCT/AU2007/001175 -4 treated and/or improving the grade of the minerals or metals that are extracted. Flotation is based on the fact that when air or gas 5 bubbles are introduced into a ground ore pulp or relatively fine particle mixtures containing minerals, particles of some minerals in the mixture or pulp will become attached to the bubbles of air or gas and float to the surface of the mixture, whereas other minerals will 10 not become attached to the air or gas bubbles but rather will remain in the pulp or mixture or will sink to the base of the vessel in which the treatment is taking place. The selective attachment of some minerals and not others allows some mineral values to be separated from other 15 minerals and/or gangue by floating the selected minerals or metals to the surface of the vessel in which the flotation occurs thus separating the selected metals or minerals from the residue remaining within or at the base of the vessel. Additionally, the selective extraction of 20 one metal also allows more of the selected metal to be recovered by floating the selected metal particles to the surface along with the air bubbles so as to concentrate the metal particles thereby extracting more of the selected particles. Thus, the use of collectors increases 25 the amount of metal or mineral recovered and also the grade of the recovered metal or mineral. Sometimes groups of similar metals are extracted in combination using bulk flotation techniques. 30 Most minerals are not water repellent in their natural state so that flotation agents or reagents must be added to the pulp in order to increase the water repellancy of the minerals which in turn increases their affinity for WO 2008/019451 PCT/AU2007/001175 -5 being entrained or adsorbed onto the air or gas bubbles. One of the most important class of reagents used in the froth flotation processes are collectors, sometimes referred to as promoters, which are adsorbed onto the 5 mineral surfaces thereby rendering the surfaces hydrophobic (or aerophilic) which facilitates attachment of the bubbles of gas or air to the mineral particles. A number of different theories have been put forwarded to explain the increase in hydrophobicity of the mineral 10 particles, such as for example, by cleaning the surface of the metal or mineral particles, by altering the polarity of the surface of the metal or mineral particle, by redistributing the change on the surface of the mineral particle and the like. It is unimportant to the scope of 15 the present invention how the increase in hydrophobicity is achieved, only that the addition of collectors or promoters improves the yield and/or selectivity of metals being recovered. Thus, the addition of collectors increases the hydrophobicity of the minerals allowing them 20 to be floated more easily. Collectors can be defined as being organic compounds which render selected minerals water repellent by adsorption of molecules or ions onto the mineral surface, reducing the 25 stability of the hydrated layer separating the mineral surface from the air or gas bubble to such a level that attachment of the particle to the bubble can be made on contact. It is the attachment of the air or gas bubble to the mineral or metal containing particle that allows the 30 particle to rise to the surface. Different collectors are used for different minerals and/or metals and for separating selected metals from other similar metals. Also different amounts of collectors are used to recover WO 2008/019451 PCT/AU2007/001175 -6 different metals in different environments and in different circumstances. Collectors are of great importance in the recovery of metal values from ores or mineral pulp because very small improvements in the 5 efficiency of the collector being used in a particular situation can have significant economic advantages for operating the recovery system for a selected metal. If the addition of the collector results in even a very small increase in the amount of metal value being selectively 10 recovered, this could make the difference between a particular process being commercially viable or not and/or the treatment of a particular ore body being economically viable. 15 Also, with an increasing emphasis on retreating or reworking old workings, such as previously treated tailings, both from a cost recovery point of view and an environmental impact point of view, the role being played by the collectors is assuming increasing importance, and 20 accordingly there is a demand for more efficient collector systems that are more economical to use by being less expensive to produce and/or requiring lower dosages to extract the selected metal or mineral and which have little or no adverse environmental effects. Thus, there 25 is a need for improved collectors and their methods of use. Accordingly, it is an aim of the present invention to provide a collector or collector system or collector 30 mixtures and/or reactions and/or product(s) of reaction(s) of reagents for use in froth flotation processes which results in improved recovery of selected mineral and/or metal values from the ore or mineral pulp, slags, WO 2008/019451 PCT/AU2007/001175 -7 tailings, waste materials, or the like being treated in the froth flotation process. Another aim of the present invention is to provide a 5 collector or collector system or collector mixtures and/or reactions and/or product(s) of reaction(s) which are useful in recovering copper, zinc, lead, nickel, platinum, palladium, other platinum group minerals and metals, gold and silver from ores, pulps, smelting slags and similar 10 raw materials containing these substances, respectively so as to enhance the commercial viability of the recovery of such substances from the raw materials containing these substances. 15 Another aim of the present invention is to provide a method of treating raw materials such as ores, pulps, slags and similar with the collectors of the present invention in flotation processes to improve the recovery of mineral and/or metal values from the raw material. 20 It has now been discovered that superior collectors can be formed from mixtures and/or reactions of two or more reagents, optionally with other chemical additives included in the reagent mixtures and/or reactions, and 25 that such combinations of collectors can be used to treat different raw materials to recover metals of interest. One problem associated with existing collectors is that some of the existing collector systems require the 30 separate addition of two or more individual collectors either at different locations within the overall installation or at different times in the operation of the installation since the collector cannot be added as a WO 2008/019451 PCT/AU2007/001175 -8 mixture because the mixture is unstable due to the individual reagents having a tendency to separate from each other within the mixtures over time or on standing or within a short period of time after stirring has stopped. 5 As an example, some existing collector mixtures separate into two liquid phases on standing when left unstirred. This is an undesirable situation since separation of the mixture into the individual components reduces the efficacy of the mixture if used in a separated or 10 partially separated state or, alternatively, the mixture requires continual stirring during storage or immediately prior to use to prevent separation, both of which either reduce the yield of the mineral and/or metal recovered or the grade of the metal recovered in the flotation process 15 or add to the cost of recovering the metal values by requiring an additional processing step and/or additional equipment to be provided in the overall treatment plant or similar. Therefore, if it were possible to discover one or more mixtures of reagents that were useful as 20 collectors, particularly in recovering zinc and/or copper and/or gold, and/or silver, and/or nickel, and/or platinum group and/or lead and/or palladium minerals and/or metals, which mixtures of reagents were stable on storage and did not require continual stirring on storage, then 25 further increases of efficiency and efficacy could be gained resulting in more economically viable recovery of metal values from the raw materials being treated. Thus, another aim of the present invention is to be able to produce a collector or collector system or collector 30 mixtures and/or reactions and/or products of reactions that have at least a reduced tendency to separate from one another or into separate phases or do not substantially separate from one another when left unstirred.

WO 2008/019451 PCT/AU2007/001175 -9 It is to be noted that not all embodiments of the present invention satisfy all of the aims of the present invention. Some embodiments will satisfy one aim whilst 5 other embodiments will satisfy another aim. Some embodiments may satisfy two or more aims. SUMMARY OF THE INVENTION 10 According to one aspect of the present invention, there is provided a collector or collector system or collector mixture and/or reaction of collectors and/or the product(s) of reactions of collectors capable of being used for concentrating metal values and/or minerals from 15 ores, mineral pulps, and/or slags or other raw materials containing metal and/or mineral in froth flotation processes, said collector, collector system or collector mixture and/or reaction comprising at least one or more reagents selected from the following groups of reagents 20 either in combination with a member from the same group of reagents, or in combination with one or more reagents selected from at least one other group or other groups of reagents in which one group of reagents is 25 A) One or more reagent(s) of a thionocarbamate having the general formula (I) R S R GC OR' (I) 30 in which R and R' are the same or different and are selected from hydrogen, alkyl groups, alkenyl groups, aryl WO 2008/019451 PCT/AU2007/001175 - 10 groups or alkaryl groups having from 1 to 20 carbon atoms including linear or branched carbon chains and substituted or un-substituted carbon atoms including being substituted with a hetero atom, 5 wherein another group of reagents is (B) one or more reagents of a dithiophosphate having the general formula (II) 10 R S P R S-M (II) in which R is the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or 15 alkaryl groups having from 1 to 20 carbon atoms, including branched or un-branched carbon chains and un-substituted or substituted carbon atoms including hetero atoms, and M is an alkali metal selected from Group I of the Periodic Table or is an ammonium ion, including substituted 20 ammonium ions or a cresyl, a substituted cresyl or a cresyl-containing group, and wherein another group of reagents is 25 (C) one or more of mercaptobenzothiazole of the general formula (III) WO 2008/019451 PCT/AU2007/001175 - 11 R NN R (III) in which R may be the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups 5 or alkaryl groups having from 1 to 20 carbon atoms including branched or unbranched carbon chains and substituted or unsubstituted carbon atoms including hetero atoms and M is hydrogen, an alkali metal selected from Group I of the periodic table, an ammonium ion, a 10 substituted ammonium ion, a cresyl, a substituted cresyl or cresyl-containing group. According to another aspect of the present invention there is provided a method of recovering at least one selected 15 metal and/or mineral from a raw material in a froth flotation process using a collector, collector system, collector mixture, collector reaction and/or collector products of a reaction of reagents comprising the steps of 20 introducing the collector to the raw material and subjecting the raw material to a froth floatation process wherein the collector or collector system or collector mixture and/or reaction of collectors and/or the product(s) of reactions of collectors are capable of being 25 used for concentrating metal values and/or minerals from ores, mineral pulps, and/or slags or other raw materials containing metal and/or mineral in froth flotation processes, said collector, collector system or collector WO 2008/019451 PCT/AU2007/001175 - 12 mixture and/or reaction comprising at least one or more reagents selected from the following groups of reagents either in combination with a member from the same group of reagents, or in combination with one or more reagents 5 selected from at least one other group or other groups of reagents in which one group of reagents is A) One or more reagent(s) of a thionocarbamate having the general formula (I) 10 R S R-N--C-- OR' (1) in which R and R' are the same or different and are selected from hydrogen, alkyl groups, alkenyl groups, aryl 15 groups or alkaryl groups having from 1 to 20 carbon atoms including linear or branched carbon chains and substituted or un-substituted carbon atoms including being substituted with a hetero atom, 20 wherein another group of reagents is (B) one or more reagents of a dithiophosphate having the general formula (II) R S P 25 R S-M (II) in which R is the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or WO 2008/019451 PCT/AU2007/001175 - 13 alkaryl groups having from 1 to 20 carbon atoms, including branched or un-branched carbon chains and un-substituted or substituted carbon atoms including hetero atoms, and M is an alkali metal selected from Group I of the Periodic 5 Table or is an ammonium ion, including substituted ammonium ions or a cresyl, a substituted cresyl or a cresyl-containing group, and wherein another group of reagents is 10 (C) one or more of mercaptobenzothiazole of the general formula (III) R -N C-SM RS R (III) 15 in which R may be the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or alkaryl groups having from 1 to 20 carbon atoms including branched or unbranched carbon chains and 20 substituted or unsubstituted carbon atoms including hetero atoms and M is hydrogen, an alkali metal selected from Group I of the periodic table, an ammonium ion, a substituted ammonium ion, a cresyl, a substituted cresyl or cresyl-containing group. 25 BRIEF DESCRIPTION OF THE INVENTION The collectors of the present invention can be used to WO 2008/019451 PCT/AU2007/001175 - 14 treat a wide variety of different raw materials, including fresh materials, virgin materials, waste materials, recycled material previously treated materials or the like including combinations of two or more such materials. 5 Typical examples of the materials that can be treated by the collectors of the present invention include sulphidic ores, slags, oxidised ores, transition ores, supergene ores, ores containing oxidized sulphides and similar. Particularly preferred ores include sulphidic ores and/or 10 sulphur containing ores. Typically, the collector of the present invention further comprises one or more additives. The additives, if present, can be one or more other collectors. The one or 15 more other collectors can be collectors in accordance with the present invention such as reagents selected from reagent groups (A), (B) or (C) either individually or in combination or in combination with other non-inventive collectors, such as for example, reagents selected from 20 another group of reagents, group (D), which are collectors that are typically conventionally or traditionally used in froth flotation separation processes. Examples of other collector reagents, group (D) reagents, are provided later in this specification. 25 In different forms of the invention, mixtures of reagents and/or reactions of reagents include the following: (i) mixtures or reactions of two or more reagents 30 selected from group (A), (ii) mixtures or reactions of two or more reagents selected from group (B), (iii) mixtures or reactions of two or more reagents WO 2008/019451 PCT/AU2007/001175 - 15 selected from group (C), (iv) mixtures or reactions of one or more reagents selected from group (A) with one or more reagents selected from group (B), 5 (v) mixtures or reactions of one or more reagents selected from group (A) with one or more reagents selected from group (C), (vi) mixtures or reactions of one or more reagents selected from group (B) with one or more reagents 10 selected from group (C), (vii) mixtures or reactions of one or more reagents from group (A) with one or more reagents from group (B) with one or more reagents from group (C). 15 In other forms, each of the above described reagent mixtures or reactions can optionally contain other collectors and/or other additives, such as for example, reagents from group (D). 20 In another form of the invention the mixture and/or reaction of reagent(s) selected from one or more of groups (A), (B) or (C) of reagents optionally containing one or more additives and/or one or more reagents/collectors (D) 25 form a stable mixture, preferably a stable mixture that does not separate when not being stirred, more preferably a stable mixture that does not separate on standing and most preferably a mixture that does not separate after mixing and does not require stirring to mix the reagents 30 prior to use, particularly shortly before or immediately before use. Reagents of the present invention in accordance with WO 2008/019451 PCT/AU2007/001175 - 16 either formula I or formula II or formula III are those in which each of R or R' may be the same or different and are each selected from one or more of methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, 5 isoamyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, n heptyl, n-octyl, m-cresyl, o-cresyl, p-cresyl, benzyl groups (-CH 2

-C

6 HB) or combinations or mixtures or isomers of two or more of the foregoing or the like including derivatives of and precursors of the reagents. Functional 10 substituents other than those exemplified are also within the scope of the present invention, such as for example, the anilino group containing the nitrogen atom. Preferred reagents useful for making collector mixtures in 15 accordance with the present invention include the following: Reagent (A) Isopropylmethylthionocarbamate 20 Isobutylmethylthionocarbamate Isopropylethylthionocarbamate Isobutylethylthionocarbamate Reagent (B) 25 Sodium di-isobutyl dithiophosphate Potassium di-isobutyl dithiophosphate Ammonium di-isobutyl dithiophosphate Sodium diethyl dithiophosphate Potassium diethyl dithiophosphate 30 Ammonium diethyl dithiophosphate Sodium di-isopropyl dithiophosphate Potassium di-isopropyl dithiophosphate Ammonium di-isopropyl dithiophosphate WO 2008/019451 PCT/AU2007/001175 - 17 Sodium di-secbutyl dithiophosphate Potassium di-secbutyl dithiophosphate Ammonium di-secbutyl dithiophosphate Ammonium dicresyl dithiophosphate 5 Cresyl dicresyl dithiophosphate Sodium dialkyl dithiophosphate Potassium dialkyl dithiophosphate Ammonium dialkyl dithiophosphate 10 Reagent (C) Mercaptobenzothiazole in the acid form Sodium Mercaptobenzothiazole Potassium Mercaptobenzothiazole 15 Preferably R of the mercaptobenzothiazole can be at any of the free aromatic positions. It is to be noted that the mercaptobenzothiazoles useful in the present invention include the acid form as well as 20 all water soluble or water miscible forms of the mercaptobenzothiazoles so that such material can be used in aqueous solutions. Particularly preferred examples of reagent (A) are 25 isopropyl Methyl Thionocarbamate (IPMT), Isobutyl Ethyl Thionocarbamate (IBET), Isobutyl methyl Thionocarbamate (IBMT), Isopropyl ethyl Thionocarbamate (IPET), including combinations of two or more of the foregoing. 30 Particularly preferred examples of reagent (B) are Potassium di-isobutyl dithiophosphate (PDIBDTP) and Potassium di-sec butyl dithiophosphate (PDSBDTP), including combinations of both.

WO 2008/019451 PCT/AU2007/001175 - 18 Particularly preferred examples of Reagent (C) are the acid form of mercaptobenzothiazole, such as for example 2 mercaptobenzothiazole, or Sodium Mercaptobenzothiazole, or 5 combinations of both. Particularly preferred collector mixtures or collector systems contain 10 (i) at least one or more of isopropyl methyl thionocarbamate and/or isopropyl ethyl thionocarbamate, and/or isobutyl ethyl thionobarbamate, 15 (ii) one or more of potassium di-isobutyl dithiophosphate and/or potassium di-sec butyl dithiophosphate, and (iii) at least one or more of isopropyl methyl 20 thionobarbamate, isopropyl ethyl thionobarbamate with one or more of potassium di-isobutyl dithiosphosphate and/or potassium di-sec butyl dithiophosphate. Additionally, suitable compounds can include 25 (i) at least one or more of isopropyl methyl thionocarbamate and/or isopropyl ethyl thionocarbamate, and/or isobutyl ethyl thionobarbamate, 30 (ii) one or more of calcium di-isobutyl dithiophosphate and/or calcium di-sec butyl dithiophosphate, and WO 2008/019451 PCT/AU2007/001175 - 19 (iii) at least one or more of isopropyl methyl thionobarbamate, isopropyl ethyl thionobarbamate with one or more of calcium di-isobutyl dithiosphosphate 5 and/or calcium di-sec butyl dithiophosphate. Additionally, esters of the above salts can be used in the present invention. 10 Examples of the alkali metal are Sodium, Potassium, Calcium and other Group IIA metals. Examples of the substituted ammonium ion are tetramethyl ammonium ion. 15 Typically, the reagent mixture can be a mixture(s) and/or reaction(s) and/or the product(s) of reaction(s) of any one of the following: (i) a single Reagent (A) with one or more other 20 Reagents (A), one or more Reagents (A) with one or more reagents (B); one or more Reagents (B) with one or more other Reagents (B), one or more Reagents (B) with one or more Reagents (C), one or more Reagents (A) with one or more Reagents 25 (C), a single reagent (C) with one or more other Reagent (C), one or more Reagents (A) with one or more Reagents (B) and one or more Reagents (C), each and any of these aforesaid mixtures and/or reactions being used together with one or more 30 additives and/or chemical compounds, including one or more other collectors, including Reagents

(D).

WO 2008/019451 PCT/AU2007/001175 - 20 Typically, the collector or collector system comprising reagents (A) and (A), (A) and (B), (B) and (B), (A) and (C), (B) and (C), (C) and (C), and (A) and (B) and (C) can contain any amounts of reagent(s) (A) and/or reagent(s) 5 (B) and/or reagent(s) (C) including from 0-100% reagent(s) (A) and 0-100% reagent(s) (B) and 0-100% reagent(s) (C), on a weight basis in any specific proportion within the weight range specified, and in any combination of amounts. 10 Typical ranges of reagents (A) (B) and (C) include the following: From 5 to 95% reagents (A), (B) or (C), from 10-90% reagents (A), (B) or (C), from 20 to 80% reagents (A), (B) 15 or (C), from 30 to 70% reagents (A), (B) or (C), from 40 to 60% reagents (A), (B) or (C), about 50% of reagents (A), (B) or (C) or the like on a weight basis. The amount of reagent (A), (B) and (C) can be the same as one another, or two may be the same as each other, or they may 20 all be different from one another. Particularly preferred collectors in accordance with the present invention include the following combination of reagents: 25 10% Isopropylethyl Thionocarbamate (IPET) (Reagent (A)) 80% Sodium Di-isobutyl Dithiophosphate (Reagent (B)) 10% Sodium Mercaptobenzothiazole (NaMBT) (Reagent (C)) 30 10% Isopropylethyl Thionocarbamate (IPET) (Reagent (A)) 90% Sodium Di-isobutyl Dithiophosphate (Reagent (B)) 30% Isopropyl Methyl Thionocarbamate (IPMT) (Reagent (A)) WO 2008/019451 PCT/AU2007/001175 - 21 70% Potassium Di-sec Butyl Dithiophosphate (Reagent (B)) 28.6% Isopropyl Methyl Thionocarbamate (IPMT) (Reagent (A)) 66.6% Potassium Di-sec Butyl Dithiophosphate (Reagent (B)) 5 4.8% Surfactant (other additive) 30% Isopropyl Methyl Thionocarbamate (IPMT) (Reagent (A)) 70% Potassium Di-isobutyl Dithiophosphate (Reagent (B)) 10 All of the above percentages expressed on a weight basis. In some embodiments, the collector or collector mixtures or collector reactions can include other collectors, such as collectors D. Examples of other collectors are 15 Xanathates (dithiocarbonates) including Xanthogen formates; dithiocarbamates; dithiophosphates, such as anilino dithiophosphoric acid including salts, esters or the like such as anilino dithiophosphates, dithiophosphinates, octyl sulphides, alcohols, hydroximic 20 acids, salts, esters and similar; and the like including combinations of two or more of the foregoing. Typically, other additives can be added to the mixture and/or reaction. Typical examples of other additives 25 include the following: Surfactants, including anionic and non-ionic surfactants, such as alkylamine ethoxylate containing from 15 to 30 moles of ethylene oxide and nonylphenol ethoxylate with 12 30 to 20 moles of ethylene oxide, or the like; other additives for other purposes including glycol ethers, dispersants, foamers, processing aids, frothers or other agents promoting frothing of the aerated mixture as well WO 2008/019451 PCT/AU2007/001175 - 22 as defoamers or the like. Additionally, the collector mixture can contain water, particularly recycled water from the treatment plant containing impurities, such as the byproducts from the various treatments occurring in 5 the treatment plants, such as for example, xanthates, or the like. Typically, the amount of surfactant added to the collector mixture and/or reaction is from about 0 to about 20% by 10 weight. Typically, the pH of the pulp and collector mixture is any value up to about 13, preferably from about 2 to 13, more preferably from about 7 to 11 and most preferably about 8 15 to 10. However, it is to be noted that the pH of the pulp and collector mixture and/or reaction can be adjusted to any value as required depending upon the content of the pulp, the nature of the metal or mineral being recovered, the type and amount of collectors being used and other 20 parameters including plant operating parameters. Typically, the amount of collector mixture and/or reaction added to the raw material is any amount up to about 200 grams per ton of ore being treated, preferably from about 25 2 g/T to about 150 g/T, more preferably, about 3 g/T to about 100 g/T, even more preferably about 3.5 g/T to about 80 g/T. The collector mixture and/or reaction can be added to the 30 raw material as a single dose, or in two or more doses, such as in two, three, four or more doses. The doses can be added separately at different time intervals and/or at different spaced apart locations.

WO 2008/019451 PCT/AU2007/001175 - 23 The collector can be added at one location within the treatment plant or at two or more different locations within the plant, such as for example, one dose can be 5 added to the grinding mill, to the rougher, to the scavenger or the like whilst other doses can be added to other parts of the plant. Typically, the metal values being recovered by the present 10 invention particularly include gold, silver, zinc,' lead, nickel, platinum group minerals and copper. Other metals or minerals can be recovered either separately or in combination with the gold, silver, zinc, lead, nickel, platinum group minerals, copper or the like. 15 Typically, the minerals being treated by the collectors of the present invention are sulphide minerals containing gold, silver, copper, lead, nickel, platinum group metals (Platinum, palladium and the like) and zinc containing 20 sulphides and the like. However, other types of minerals can be treated such as oxides, oxidised sulphides or the like. BRIEF DESCRIPTION OF THE DRAWINGS 25 The present invention will now be described by way of non limiting examples with particular reference to the following examples illustrating aspects of the present invention which will be described with reference to the 30 accompanying drawings in which: Figures la and lb are plots of the grade of copper in flotation concentrates expressed as a percentage as a WO 2008/019451 PCT/AU2007/001175 - 24 function of the amount of copper recovered to the concentrates from the ore sample using four different collectors at pH10 (Figure la), and at pHi (Figure 1b), respectively; 5 Figures 2a to 2d are plots of the grade of copper present in flotation concentrates expressed as a percentage as a function of the amount of copper recovered to the concentrates from the ore samples expressed as a 10 percentage using 4 different collectors all at a pH of 10; Figure 3 is a plot of the amount of copper recovery to flotation concentrate expressed as a percentage of the total amount in the sample tested as a function of the 15 flotation time taken to recover the copper expressed in minutes using two different collectors and at three different pH's; Figure 4(a) is a plot of total Zinc Recovery measured as a 20 percentage as a function of collector dosage measured in g/t relative to the zinc flotation feed; Figure 4(b) is a plot of the grade of zinc recovered to the zinc concentrates measured as a percentage as a 25 function of the amount of zinc recovery measured as a percentage; Figure 5(a) is a plot of silver recovery to zinc concentrates as a function of zinc recovery to the zinc 30 concentrates, Figure 5(b) is a plot of iron recovery as a function of zinc recovery, WO 2008/019451 PCT/AU2007/001175 - 25 Figure 6(a) is a plot of the grade of zinc recovered to the zinc concentrate measured as a percentage as a function of the amount of zinc recovery measured as a 5 percentage; and Figure 6(b) is a plot of the amount of zinc recovery to flotation concentrates expressed as a percentage of the total amount in the sample tested as a function of the 10 flotation time taken to recover the copper expressed in minutes. DETAILED DESCRIPTION OF THE INVENTION 15 EXAMPLE 1 SAMPLES TESTED Samples of flotation feed cyclone overflow mineral pulp were taken from the plant. The mineral pulp samples taken 20 were sub sampled directly for flotation testing so that the laboratory tests were completed at plant pulp density, using plant pulps obtained using plant circuit water. In the plant, all collectors were added after the cyclone overflow, so that the samples did not contain fresh plant 25 collector but rather only contained residual collector from the circuit water added to the mineral grind to form the pulp. Head grades of the amounts of different metals in the 30 samples were determined using the averages of the calculated head grades obtained from the flotation tests, and were calculated to be 3.64% Cu and 17.0%Fe for the sample tested. Thus, on average the mineral sample tested WO 2008/019451 PCT/AU2007/001175 - 26 contained 3.64% Cu along with 17.0% Fe. Lime (calcium oxide) was being added to the plant grind, as the pH of the pulp was 8.5. For the tests the pH was 5 adjusted with lime as required to achieve a range of pH values up to pH 11.0. TEST CONDITIONS 10 All test involved collector doses to the scavenger (and in some tests also to the rougher), and frother additions to the scavenger. The frother used was OTX140. The variables tested were collector type and flotation pH. The designations scavenger, rougher, and the like are 15 different components of the overall treatment plant. The collector types tested, reagent additions and flotation times are shown in Table 1. 20 Table 1 Test pH Collector Dose uL Dose uL OTX140 Type Rghr Scav 1 uL scav 1 38 8.5 1 0 25 10 Sluggish froth 39 10.0 2 0 25 10 Good free flowing froth 40 8.5 2 0 25 10 41 10.0 1 0 25 10 42 11.0 1 0 25 43 11.0 2 0 25 10 44 10.0 3 0 25 10 Best yet. Very nice, loaded free flowing froth. 45 10.0 3 10 25 10 46 10.0 2 10 25 10 Very good float. Very barren at end. 47 10.0 1 10 25 10 48 11.0 3 0 25 10 49 10.0 4 0 25 10 50 11.0 4 0 25 10 51 10.0 4 10 25 10 Tests 38 to 51 flotation times were: Rghr 1 (Con 1) = 2 min Scav 1 (Conc 2) = 2 min Scav 2 (Con 3) = 3 min WO 2008/019451 PCT/AU2007/001175 - 27 Collectors #2, #3 and #4 referred to in Table 1 are collectors in accordance with the present invention, 5 whereas collector #1 is a conventionally used collector included as a control and/or comparative example. Collector was not added for rougher flotation in all tests, rather the collector additions were only to the 10 scavenger feed. There seemed to be sufficient naturally floating copper sulphide mineral to achieve good rougher flotation without direct collector additions. The collector doses were based on amounts established as a 15 result of other investigations to determine the optimum amounts in accordance with normal plant practice. RESULTS 20 Detailed results are included in Table 2. Results for the total concentrate for each test are shown in Table 2.

WO 2008/019451 PCT/AU2007/001175 - 28 Table 2 Summary of Results to the Total Rougher - Scavenger Concentrate Collector Assays % Recoveries Test pH Type g/t Rghr g/t Scav Total g/t Cu Fe CU Fe Effect of pH on Total Rougher Concentrate Results 38 8.5 #1 17 17 23.5 25.2 69.4 14.9 41 10 #1 17 17 24.5 24.6 72.3 14.9 42 11 #1 17 17 24.4 25.2 81.7 19.3 40 8.5 #2 17 17 24.6 25.9 69.3 16.9 39 10 #2 17 17 23.0 25.6 73.2 18.8 43 11 #2 17 17 21.6 26.8 83.7 24.5 44 10 #3 17 17 22.7 24.2 76.3 18.2 48 11 #3 17 17 22.4 26.0 83.7 19.9 49 10 #4 17 17 23.2 24.5 64.2 13..2 50 11 #4 17 17 22.6 24.3 78.9 17.2 Effect of Collector Dose 41 10 #1 17 17 24.5 24.6 72.3 14.9 47 10 #1 7 17 24 23.3 23.0 64.6 13.1 39 10 #2 17 17 23.0 25.6 73.2 18.8 46 10 #2 7 17 24 23.9 24.1 67.5 15.3 44 10 #3 17 17 22.7 24.2 76.3 18.2 45 10 #3 7 17 24 23.4 23.2 73.3 15.1 49 10 #4 17 17 23.2 24.5 64.2 13.2 51 10 #4 7 17 24 22.0 24.1 68.4 16.1 5 The results shown in Table 2 identify the number of the test sample being tested under the heading "Test' and indicate the pH of the pulp with added collector under the heading -pH". 10 The column headed "Collector" identifies the type of collector being tested under the heading "type" and the amount of collector measured in grams per ton added to the mineral pulp in the Rougher (g/t Rghr), in the Scavenger 15 (g/t Scav) and the total amount added (Total g/t). It is to be noted that collector #2, #3 and #4 are in accordance WO 2008/019451 PCT/AU2007/001175 - 29 with the present invention whereas collector #1 is a standard collector used as a control and as a comparative example of a conventional collector. 5 The column headed "Assays %" indicates the grade of copper in the material extracted from the mineral pulp and the amount of Iron extracted along with the copper. It is to be noted that it is desirable that the value of the grade of copper (Assay %Cu) be as high as possible, and the 10 amount of iron (Assay % Fe) be as low as possible indicating that copper is selectively extracted in preference to also extracting iron so as to improve the efficiency of the flotation process in favour of the extraction of Cu. 15 The column headed "Recoveries" indicates the amount of copper and iron that is recovered from the mineral pulp using the various collectors. Again, it is preferable that the amount of copper recovered (Recoveries % Cu) be 20 as high as possible whilst the amount of iron being recovered (Recoveries % Fe) be as low as possible so that the flotation process is efficient in selectively recovering Cu. 25 A review of the results of Table 2 reveal that it can be seen that collector type #2 in accordance with the present invention was at least as good as collector type #1 and that the best results were obtained at higher pH of about pH 10 and pH 11. 30 The results of Table 2 show conclusively that the overall fastest flotation kinetics as indicated by the amount of copper recovery was obtained using collector #2 at a pH of WO 2008/019451 PCT/AU2007/001175 - 30 11 in which 83.7% of copper was recovered as compared to only 69.3% Cu being recovered at pH 8.5. Additionally, it was observed that collector #1 continued 5 to give sticky and sluggish froth characteristics, and when doses where increased to maximize copper recovery, the froth conditions became more sluggish and overall recovery was reduced; compare tests 41 to 47 in Table 2. The effect was reduced when collector #2 was used; compare 10 tests 39 and 46. Collector #2 did not separate and its use provided good flotation performance whilst producing a more free flowing froth thus providing better selectivity and recovery of 15 copper than collector #1. It was also observed that increasing the pH up to about pH 11 produced faster copper flotation kinetics with increased copper recovery, and with little effect on 20 overall selectivity and concentrate grades. Copper grade recovery curves for roughing and scavenging are shown in Figure 1. 25 The effects of extra collector added to the rougher are shown in Figure 2. The effects of pH and collector #1 as compared to collector #2 on copper recovery versus flotation time are 30 shown in Figure 3. From Figure 3 it was concluded that fastest copper flotation kinetics were achieved from collector #2, compared to collector #1 at equivalent pH values.

WO 2008/019451 PCT/AU2007/001175 - 31 EXAMPLE 2 A fresh sample of zinc flotation feed (lead scavenger 5 tail) was taken from the auto sampling point for this stream. The sample was sub-sampled from the pulp to provide flotation test samples. The standard test procedure is shown in Table 3. 10 Table 3 Standard Test Conditions OBJECTIVE: Sample of Pb Tails (Zn Feed) Objective to evaluate Zn collectors CuSO4 Collector #5 Frother Lime Air pH COND FLOAT (min) (min) Pulp 8.4 Cond yes 9.5 2 Cond 10 830 9.5 3 Cond 90 70 10 8 Yes 9.5 1 Rr 110 2 -- -- -- -- 2- 20 -- ---15 -- --- ---- -Yes - --- 12 - 9.5-*- - 1 - ---- 3- - Rh320 15 5 4 Yes 12 9 .5 1 4 All flotation products were dried, weighed and dispatched for preparation and chemical analysis. 15 Variations to the standard procedure included replacing Collector #5 with several different other collectors, identified as collectors #6, #7, #8, #9, #10 and #11 as well as reducing the doses of collectors. 20 A total of 21 tests were completed. It is to be noted that collector #5 is a conventional WO 2008/019451 PCT/AU2007/001175 - 32 collector not in accordance with the present invention and is included as a control sample as a comparative example whereas collectors #6, #7, #8, #9, #10 and #11 are collectors in accordance with the present invention. 5 RESULTS All the calculated head grades are summarised in Table 4. Generally, the calculated head grades were close to the average and within the acceptable limits of 10%. Hence, 10 the data and mass balance results were considered valid. Summarised conditions and results for all tests are shown in Table 5 (except test 24 which gave poor results due to the incorrect and very high pH). 15 Grade and recovery curves for zinc and selectivity curves are shown in Figures 4 and 5. Only tests considered to give good results were plotted against the standard tests.

WO 2008/019451 PCT/AU2007/001175 - 33 Table 4 Calculated Head Grades * Test e e Assay * * No * Pb * Zn% Cu% 9 Fe e Ag % % g/t * * 0.63 9 18.0 * 0.12 0 7.09 9 21 e 26 9 0.60 e 17.6 * 0.12 * 7.35 e 20 * 27 0 0.61 e 15.9 * 0.11 0 6.97 * 19 * 28 9 0.65 9 18.8 * 0.12 * 7.35 9 22 * 29 0 0.64 * 19.2 0 0.12 0 7.61 9 22 e 30 0 0.62 * 17.6 & 0.11 0 7.44 9 19 e 31 0 0.61 e 18.9 0 0.11 0 7.56 9 20 * 32 0 0.58 9 17.5 0 0.11 0 7.35 e 18 * 33 9 0.58 * 18.7 0 0.11 0 6.94 9 18 * 34 * 0.63 e 16.4 0 0.11 0 7.20 * 14 * 35 0 0.66 0 18.1 * 0.11 0 7.51 9 18 * 36 0 0.60 e 18.4 a 0.11 e 7.19 e 18 * 37 0 0.61 & 16.8 * 0.12 0 7.35 9 17 e 38 0 0.64 * 17.1 0 0.12 9 7.46 * 16 e 39 0 0.62 9 18.8 0 0.11 0 7.25 9 20 * 40 * 0.63 & 16.4 0 0.10 e 7.11 9 18 0 41 0 0.62 e 17.1 0 0.09 0 6.75 @ 17 0 42 0 0.65 9 18.2 * 0.10 e 6.73 9 18 0 43 0 0.61 9 18.0 * 0.09 * 6.80 9 16 e 44 0 0.66 9 18.2 * 0.09 0 7.00 9 19 e Average 9 0.62 9 17.8 a 0.11 0 7.20 e 18 WO 2008/019451 PCT/AU2007/001175 - 34 Table 5 Summarised Test Results Test Collectors: Wt Assay Recoveries % No Type g/t % Pb% Zn% Cu% Fe% Ag g/t Pb Zn Cu Fe Ag 25 5 108 30.6 1.2 56.6 0.2 3.8 45.3 56.9 96.4 49.1 16.3 66.7 26 5 67 23.4 1.2 56.1 0.2 3.69 45.6 48.0 74.3 34.0 12.4 53.7 27 5 46 9.7 2.3 45.4 0.2 4.8 71.9 36.2 27.7 19.6 6.7 37.2 28 6 67 31.9 1.2 57.9 0.2 4.5 48.7 59.0 97.9 59.4 19.4 71.7 29 6 46 31.0 1.2 56.0 0,2 4.5 47.8 58.2 90.6 48.9 18.4 68.2 30 6 33 25.0 1.2 56.5 0.2 4.1 46.3 49.1 80.2 40.4 13.8 60.7 31 7 67 31.9 1.1 57.1 0.2 4.2 43.3 57.7 96.4 57.6 17.6 69.3 32 7 46 28.8 1.1 55.2 0.2 4.4 42.5 54.7 90.7 47.4 17.2 68.2 33 7 33 27.1 1.1 54.0 0.2 3.8 41.3 52.5 78.1 41.2 14.9 63.0 34 5 33 6.5 2.8 32,5 0.3 5.1 81.3 29.3 12.9 15.4 4.6 38.7 35 5 108 29.6 1.1 56.1 0.2 4.0 39.5 49.8 91.9 43.6 15.7 64.9 36 8 67 30.9 1.1 55.0 0.2 3. 8 41.5 56.5 92.5 56.1 16.4 69,9 37 8 46 23.4 1.2 50.5 0.2 3.4 41.5 44.9 70.4 35.7 10.8 58.4 38 8 33 18.7 1.5 52.6 0.2 4.0 48.7 43.8 57.6 31.9 10.1 55..5 39 9 67 34.6 1.1 53.1 0.2 4.5 41.6 61.0 97.9 65.5 21.5 70.9 40 9 46 30.1 1.1 52.3 0.2 4.4 40.5 53.0 96.1 63.5 18.4 66,0 41 9 33 30.7 1.1 52.7 0.2 3.6 40.5 54.1 94.5 63.1 16.3 75.0 42 10 46 35.2 1.1 49.7 0.2 3.8 39.4 58.9 95.8 68.1 20.1 78.1 43 10 33 30.3 1.0 52.5 0.2 3.7 38.5 50.9 88.7 61.2 16.5 73.6 44 11 33 26.9 1.2 54.9 0,2 3.9 42.9 51.0 81.4 58.1 15.0 61.3 Average of the duplicate standard tests 25 & 35 5 108 30.1 1.1 56.3 0.2 3.9 42.4 53.3 94.1 46.3 16.0 65.8 WO 2008/019451 PCT/AU2007/001175 - 35 Comments on the results are as follows: > Best zinc flotation kinetics and highest zinc recoveries with low doses of collector were from 5 Collector #9. Refer Figure 4. With collector doses as low as 33g/t, the flotation kinetics were faster than Collector #5 at 108g/t, and overall zinc recoveries were similar. At higher doses of Collector #9, the zinc flotation kinetics were similar, however overall 10 recoveries were slightly higher, reaching 97.9% for a dose of 67g/t. > Collector #9 showed slightly lower zinc grades in the zinc concentrates than Collector 5(and lower than Collector #6 and Collector #7 which gave the best 15 performance). Froth conditions were noted to be slightly stronger when Collector #9 was used, and it is likely the stronger froth allowed less froth drainage and more gangue hold up, diluting the concentrate grades. It is likely a reduction in 20 frother dose or a change to a weaker frother when Collector #9 is used would allow for both high concentrate grades and maintain the high zinc recoveries with low doses of collector. > The best zinc grade and recovery performances were 25 from Collector #6 and Collector #7, at 67g/t for each, as shown in Figure 4. These tests gave significantly better performance than either of the duplicate standard tests with 108g/t of Collector #5. Collector #6 gave the best performance (test 28), and 30 also achieved a very high total zinc recovery of 97.9%. > Silver recovery with respect to zinc recovery is WO 2008/019451 PCT/AU2007/001175 - 36 shown in Figure 5. There was little variation between the tests, and hence the lower doses of collectors in accordance with the present invention did not cause any reduction in silver recovery. 5 > Iron recovery with respect to zinc recovery is also shown in Figure 5. Again there was little variation between the tests. Selectivity from iron (pyrite) was not affected by the use of the collectors in accordance with the present invention. 10 > Collector #8 gave excellent results with flotation performance better than Collector #5 at the same doses. At 67g/t, Collector #5 achieved 74.3% zinc recovery, while at the same dose, Collector #8 achieved 92.5% zinc recovery. However Collector #8 15 performance was not as good as Collector #6, Collector #7 and Collector #9.. > The tests with Collector #5 at lower doses, (as per tests with the collectors in accordance with the present invention) gave low zinc recoveries. Refer 20 Figure 4, and tests 26, 27 and 34 shown in Table 4. CONCLUSIONS > Collector #6 and Collector #7 gave better zinc flotation performance for zinc flotation kinetics, 25 grade and recovery performance, and overall recoveries, than Collector #5. > Collector #6 and Collector #7 achieved these excellent results with only 67g/t of collector additions, compared to the inferior results achieved 30 with a higher dose of 108g/t of Collector #5. Hence, the collectors in accordance with the present invention dose was almost half (62%) of the Collector WO 2008/019451 PCT/AU2007/001175 - 37 #5 dose, and still achieved better flotation performance. > Collector #9 also achieved excellent flotation performance with doses as low as 46g/t, however, 5 stronger froth conditions (the frother dosage was not adjusted) caused slightly lower zinc grades (down from around 56% to 51%Zn). Collector #9 may be an excellent collector with low doses, using lower frother additions or an alternative frother. 10 > Collector #8 which gave excellent results in earlier testwork again gave good results. The chemistry of Collector #8 was used to prepare Collector #6 and Collector #7, hence, good flotation performance has been consistent with the basic chemistry for these 15 three collectors. Collector #6 gave the best overall zinc flotation performance, with the highest zinc recovery of 97.9%, best zinc grade and recovery relationship, and at only 67g/t 20 total addition. This result compared to only 74.3% zinc recovery from Collector #5 at the same dosage, and only 94.1% recovery (average of duplicate tests) at 108g/t dosage. 25 Collector #9 produced the highest zinc recoveries for the lowest dosages of collector; however some froth conditions affected the concentrate grades slightly. EXAMPLE 3 30 PROCEDURE A fresh sample of zinc flotation feed (lead scavenger WO 2008/019451 PCT/AU2007/001175 - 38 tail) was taken from the auto sampling point for this stream. The sample was sub-sampled from the pulp to provide flotation test samples. 5 The standard test procedure with the standard Collector #5 is shown in Table 6. Table 6 Standard Test Conditions OBJECTIVE: Sample of Pb Tails (Zn Feed) Objective to evaluate Zn collectors CuSO4 Collector #5 IF56 Lime Air pH COND FLOAT (min) (min) Pulp 8.4 Cond yes 9.5 2 Cond 10 833 9.5 3 Cond 90 75 10 8 Yes 9.5 2 Rgh r 1 10 9.5 2 Rght2 20 17 5 4 Yes 12 9.5 1 3 P~h3 20 17 5 4 Yes 12 9.5 1 4 Total reagents 833 108 16 1 1 10 All flotation products were dried, weighed and dispatched for preparation and chemical analysis. Variations to the standard procedure included replacing the 108g/t of collector #5 with collector #6 and collector 15 #12 at addition rates as low as 42g/t, and testing collector #5 at a lower addition rate. A total of 6 tests were completed.

WO 2008/019451 PCT/AU2007/001175 - 39 RESULTS It is to be noted that collector #5 is a control sample included as a comparative example whereas collectors #6 and #12 are collectors made in accordance with the present 5 invention. Further, collector #12 is a modified form of collector #6. Details of all tests and results are shown in accompanying Tables 7 and 8. 10 All the calculated head grades are summarised in Table 7. Generally, the calculated head grades were close to the average and within the acceptable limits of 10%. Hence, the data and mass balance results were considered valid. 15 Summarised conditions and results for all tests are shown in Table 7. Table 7 Calculated Head Grades Test Pb% Zn% Cu% Fe% 46 0.90 11.3 0.07 6.87 47 0.85 11.2 0.07 6.74 48 0.86 11.4 0.06 6.45 49 0.88 11.2 0.06 6.79 50 0.89 11.3 0.06 6.69 51 0.87 11.3 0.06 6.85 Average 0.88 11.3 0.06 6.73 WO 2008/019451 PCT/AU2007/001175 - 40 Table 8 Summarised Test Results Test Collector Dose Assay Recoveries % No g/t Pb% Zn% Cu% Fe% Ag g/t Pb Zn Cu Fe Ag Rougher Conc 1 46 #5 75 1.85 55.0 0,19 3.8 78 32.1 76.0 42.7 8.7 36.3 47 #6 50 2.38 53.6 0.21 4.3 96 53.3 91.3 57.0 12.2 53.4 48 #12 50 2.43 52.0 0.21 4.5 95 56.5 91.6 64.9 14.0 57.2 49 #12 33 2.33 55.4 0.19 4.2 94 46.8 87.1 57.5 10.9 50.4 50 #6 33 2.7 56.0 0.2 4.1 95 53.4 87.3 60.0 10.8 51.3 51 #5 33 1.94 57.8 0.17 3.2 86 27.1 62.6 36.3 5.7 31.8 Rougher Cons 1 and 2 46 #5 92 2.22 50.0 0.20 5.02 87 52.5 93.9 62.0 15.5 55.1 47 #6 58 2.71 47.8 0.23 5.80 105 72.0 96.5 72.7 19.5 69.5 48 #12 58 2.76 46.4 0.23 4.49 104 75.4 96.0 82.1 16.4 73.8 49 #12 37 2.71 50.1 0.21 5.54 104 66.4 95.9 77.2 17.5 67.9 50 #6 37 2.96 50.8 0.21 5.25 103 70.9 95.9 77.1 16.7 67.1 51 #5 37 2.25 55.4 0,18 3.83 92 47.1 89.9 58.6 10.2 51.0 Total Rougher Conc 46 #5 108 2.61 43.7 0.22 6.48 98 72.6 97.0 78.5 23.7 73.2 47 #6 67 2.72 43.6 0.22 6.56 104 79.8 97.3 78.8 24.4 76.1 48 #12 67 2.74 42.7 0.22 5.45 103 81.9 96.5 88.6 21.8 79.9 49 #12 42 2.77 45.3 0.21 6.43 105 75.8 97.0 87.0 22.8 76.9 50 #6 42 2.97 45.6 0.21 6.33 104 80.3 97.2 87.0 22.7 76.6 51 #5 42 2.55 50.8 0.20 4.80 100 62.0 95.7 72.4 14.9 64.1 WO 2008/019451 PCT/AU2007/001175 - 41 Comments on the results are as follows: > Best flotation performance was achieved from test 49, 5 with a total of only 42g/t Collector #12. Overall zinc recovery was 97.0% at a grade of 45.3% Zn, compared to 108g/t of Collector #5 achieving the same recovery at a lower grade of 43.7%. (Refer Table 8). > Fastest flotation kinetics were from tests with 10 Collector #6 or Collector #12 at a total dose of 67g/t (tests 47 and 48). > The initial dose of only 33g/t to the first concentrate gave over 87% Zn recovery for Collector #12. The same collector dose for concentrate 1 from 15 Collector #5 gave only 62.6% Zn recovery (test 51). > Zinc grade versus zinc recovery curves were in a similar position for all tests, however Collector #6 and Collector #12 gave faster flotation kinetics and overall similar or slightly higher zinc recoveries 20 than Collector #5 as shown in Figures 6a and 6b. > Throughout the staged roughing, Collector #6 and Collector #12 gave higher silver recoveries versus zinc recoveries than tests with Collector #5. This is a desirable result as it achieves higher silver 25 recoveries to a selectable concentrate. > Selectivity from iron was similar for all tests and all collectors. CONCLUSIONS 30 > Collector #6 and Collector #12 were confirmed as being much better collectors for zinc flotation than the current standard collector, Collector #5.

WO 2008/019451 PCT/AU2007/001175 - 42 A Best results were achieved with Collector #12. SUMMARY 5 Following very successful testing of Collector #6 of Example No. 2 for zinc flotation, and the subsequent deletion of cyanide from the standard flotation reagent regime, a brief laboratory test program was completed to confirm the excellent performance of Collector #6 in 10 cyanide free pulp. The zinc feed grade at the time was 11.3%. The testwork was completed on zinc flotation feed pulps. 15 Collector #6 and Collector #12 were tested and compared with the current standard collector, Collector #5. Test results confirmed the excellent performance of both Collector #6 and Collector #12 and confirmed the earlier 20 work. The removal of cyanide did not affect the excellent performance of collectors in accordance with the present invention. Results are summarised below: 25 Test Collector Dose Assay Recoveries % No g/t Zn Ag g/t Zn Ag Total Rougher Conc 46 Collector #5 108 43.7 98 97.0 73.2 49 Collector #12 42 45.3 105 97.0 76.9 WO 2008/019451 PCT/AU2007/001175 - 43 The advantages of Collector #12 over Collector #5 are v Much lower dose rates (108g/t Collector #5 compared to 42g/t Collector #6) Faster flotation kinetics with the lower dose of 5 Collector #12 compared to the higher dose of Collector #5 (and a lower dose of Collector #5 was also tested but was not effective). V Slightly higher zinc concentrate zinc grades with the low dose of Collector #12. 10 Higher silver recovery to the zinc concentrates with Collector #12. v Similar selectivity from iron minerals (assumed to be pyrite). The performance of the Collector #12 was not 15 affected by the removal of cyanide from the preceding copper and lead flotation circuits. Example 4 20 The work of this example was completed at the treatment site, using plant cyclone overflow samples, and tested in the site laboratory with collector #13 which is made in accordance with the present invention and compared with a standard collector, in this case collector #1, a 25 conventional collector not in accordance with the present invention. For each day of testing, a fresh sample of cyclone overflow sample from the plant was taken in the morning, 30 and sub-sampled for all the testing completed during that day. Lime had been added in the plant and hence the pH had been adjusted in the plant before the sample was taken.

WO 2008/019451 PCT/AU2007/001175 - 44 However the collector and frother had not been added. Hence, the collector and frother were added in the laboratory. 5 Staged rougher concentrates were removed for analysis. Most flotation tests were completed in duplicate, to maximise the confidence in the results. 10 Results of the testing are summarized in Table 9. The results in the table included weighted average results for tests completed in duplicate and triplicate. Table 9: Test No Collector Calc Head Assays: Rghr Conc Total Rougher Recoveries % Cu % Aug/t Cu % Au g/t Cu Fe Au Ag 47 #13 1.21 0.37 11.9 2.66 93.5 17.1 67.3 70.3 48 #13 1.24 0.39 11.7 2.96 93.8 17.0 75.7 71.7 43 #1 1.19 0.38 10.3 2.51 93.0 17.8 71.7 70.5 46 #1 1.22 0.37 12.3 2.56 93.4 16.2 63.4 81.7 49 #1 1.20 0.37 11.6 2.59 94.0 16.6 68.2 69.3 Ave 47, 48 #13 1.22 0.38 11.8 2.81 93.7 17.0 71.6 71.0 Ave 43, 46, 49 #1 1.20 0.37 11.3 2.55 93.5 16.9 67.8 73.3 15 Example 5 The sample used in this example is a blend of: 20 e 10% Pyrite Skarn * 10% Magnetite Skarn e 80% Monzonite Porphory The head grade was 0.96% Cu, 1.16 g/t Au and 6.6% S. 25 Average results from replicate tests are as follows: WO 2008/019451 PCT/AU2007/001175 - 45 Table 10: Concentrate Tails Assays Distribution % Assays Distribution % Collector Cu % Au g/t S % Cu % Au g/t S% Cu % AU g/t S% Cu % Au g/t S Average #15 11.8 8.59 32.4 87.0 50.2 35.0 0.135 0.73 4.66 13.0 49.8 65.0 Average #16 11.0 8.29 35.6 87.9 56.4 45.2 0.125 0.53 3.85 12.1 43.6 54.8 Average #14 13.2 8.69 30.6 87.3 56.9 29.5 0.130 0.45 4.99 12.7 43.1 70.5 Collectors #14 and #16 are in accordance with the present 5 invention whereas collector #15 is a conventional , collector not in accordance with the present invention and used as a control for comparison purposes. These results show a significant improvement in copper 10 recovery of 0.9%, for collector #16. Both collectors #14 and #16 show an improvement in gold recovery. Laboratory flotation tests with collector #16 and collector #14 were completed at the mine site laboratory 15 to examine the flotation performance of these collectors relative to the standard collector, collector #15. Test results are summarized in Table 11.

WO 2008/019451 PCT/AU2007/001175 - 46 Table 11. Grades and Recoveries to Flotation Concentrates and Tail Concentrate Tails Assays Distribution % Assays Distribution % Collector Cu % Au g/t S % Cu % Au g/t S % Cu % Au g/t S % Cu % Au g/t S Test 2: #15 12.2 9.61 32.4 86.9 58.9 32.3 0.134 0.49 4.96 13.1 41.1 67.7 Test 3: #15 11.3 7.19 34.3 87.5 31.4 34.3 0.129 1.26 5.28 12.5 68.6 65.7 Test 9: #15 11.9 8.96 30.4 86.7 60.3 38.6 1.141 0.46 3.75 13.3 39.7 61.4 Test 4: #16 9.0 6.36 39.5 87.4 51.2 57.5 0.133 0.62 3.00 12.6 48.8 42.5 Test 5: #16 9.1 9.58 39.1 88.6 66.9 53.8 0.117 0.47 3.35 11.4 33.1 46.2 Test 6: #16 14.9 8.92 28.1 87.7 51.1 24.2 0.124 0.51 5.21 12.3 48.9 75.8 Test 7: #14 12.0 8.22 32.6 86.8 57.4 31.7 0.137 0.46 5.26 13.2 42.6 68.3 Test 8: #14 14.3 9.16 28.6 87.9 56.5 27.3 0.122 0.44 4.71 12.1 43.5 72.7 Average #15 11.8 8.59 32.4 87.0 50.2 35.0 0.135 0.73 4.66 13.0 49.8 65.0 Average #16 11.0 8.29 35.6 87.9 56.4 45.2 0.125 0.53 3.85 12.1 43.6 54.8 Average #14 13.2 8.69 30.6 87.3 56.9 29.5 0.130 0.45 4.99 12.7 43.1 70.5 5 The averaged results show both collectors #14 and #16 performed well compared to the average of the collector #15, the standard collector, particularly with increased gold recovery. Copper recovery was higher for both 10 collectors #14 and #16 than for collector #15 and collectors #14 and #16 achieved lower copper grades in tails than did collector #15. In particular, there was an average increase of 0.9% copper recovery for collector #16 compared to collector #15. This recover increase is 15 significant and demonstrates the superior performance of collector #16. The results indicate that the performance of both collectors #14 and #16 are superior to the performance of 20 collector #15, the control sample. ADVANTAGES OF THE INVENTION Advantages of the invention include that collectors WO 2008/019451 PCT/AU2007/001175 - 47 containing at least one reagent A and at least one reagent B and/or reaction of them are efficient and efficacious in selectively recovering greater amounts of a selected metal and/or mineral, most notably, copper, gold, silver, lead, 5 nickel, platinum group minerals or zinc, particularly from sulphide ores as well as producing a better grade of selected metal or mineral. Another advantage of the present invention is that the 10 combination of reagent A and reagent B has a reduced tendency to separate into different components or phases, thereby requiring less stirring or agitation and/or allowing the combination to be added as a single mixture therefore providing more efficiency and requiring less 15 equipment. Another advantage of the present invention is that lesser amounts of collectors in accordance with the present invention can be used to extract selected minerals/metals 20 so that lower dosage rates can be used when compared to the dosage amounts of conventional collectors. Another advantage is that the collector of the present invention achieve better froth quality allowing better 25 froth mobility to transfer from the flotation cell to the launder that collects the concentrates. Better froth mobility allows for more efficient recovery to the concentrate and contributes to faster flotation kinetics. 30 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any WO 2008/019451 PCT/AU2007/001175 - 48 other country. It will be understood to persons skilled in the art of the invention that many modifications may be made without 5 departing from the spirit and scope of the invention.

Claims

1. A collector or collector system or collector mixture and/or reaction of collectors and/or the 5 product(s) of reactions of collectors capable of being used for concentrating metal values and/or minerals from ores, mineral pulps, and/or slags or other raw materials containing metal and/or mineral in froth flotation processes, characterized in that the collector, collector 10 system or collector mixture and/or reaction comprises at least one or more reagents selected from the following groups of reagents either in combination with a member from the same group of reagents, or in combination with one or more reagents selected from at least one other 15 group or other groups of reagents in which one group of reagents is A) One or more reagent(s) of a thionocarbamate having the general formula (I) 20 R S R-N- C---OR' (1) in which R and R' are the same or different and are selected from hydrogen, alkyl groups, alkenyl groups, aryl 25 groups or alkaryl groups having from 1 to 20 carbon atoms including linear or branched carbon chains and substituted or un-substituted carbon atoms including being substituted with a hetero atom, 30 wherein another group of reagents is WO 2008/019451 PCT/AU2007/001175 - 50 (B) one or more reagents of a dithiophosphate having the general formula (II) R S P R S-M(II) 5 in which R is the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or alkaryl groups having from 1 to 20 carbon atoms, including branched or un-branched carbon chains and un-substituted 10 or substituted carbon atoms including hetero atoms, and M is an alkali metal selected from Group I of the Periodic Table or is an ammonium ion, including substituted ammonium ions or a cresyl, a substituted cresyl or a cresyl-containing group, and wherein 15 another group of reagents is (C) one or more of mercaptobenzothiazole of the general formula (III) 20 R -N C-SM R (III) in which R may be the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups 25 or alkaryl groups having from 1 to 20 carbon atoms WO 2008/019451 PCT/AU2007/001175 - 51 including branched or unbranched carbon chains and substituted or unsubstituted carbon atoms including hetero atoms and M is hydrogen, an alkali metal selected from Group I of the periodic table, an ammonium ion, a 5 substituted ammonium ion, a cresyl, a substituted cresyl or cresyl-containing group.

2. A collector or collector system according to claim 1 characterised in that the mixtures of reagents 10 and/or products of reactions of reagents or reactions of reagents forming the collector or collector system include the following (i) mixtures or reactions of two or more reagents 15 selected from group (A), (ii) mixtures or reactions of two or more reagents selected from group (B), (iii) mixtures or reactions of two or more reagents selected from group (C), 20 (iv) mixtures or reactions of one or more reagents selected from group (A) with one or more reagents selected from group (B), (v) mixtures or reactions of one or more reagents selected from group (A) with one or more reagents 25 selected from group (C), (vi) mixtures or reactions of one or more reagents selected from group (B) with one or more reagents selected from group (C), (vii) mixtures or reactions of one or more reagents 30 from group (A) with one or more reagents from group (B) with one or more reagents from group (C). WO 2008/019451 PCT/AU2007/001175 - 52

3. A collector or collector system according to claim 1 or 2 characterized in that the collector or collector system includes other additives or reagents including reagents of group (D). 5

4. A collector or collector system according to any one of claims 1 to 3 characterized in that the reagent mixture and/or reagent reaction or reagent reaction product is selected from any one of the following: 10 a single Reagent (A) with one or more other Reagents (A), one or more Reagents (A) with one or more reagents (B); one or more Reagents (B) with one or more other Reagents (B), one or more 15 Reagents (B) with one or more Reagents (C), one or more Reagents (A) with one or more Reagents (C), a single reagent (C) with one or more other Reagent (C), one or more Reagents (A) with one or more Reagents (B) and one or more Reagents (C), 20 including each and any of the aforesaid mixtures and/or reactions being used together with one or more additives and/or chemical compounds, including one or more other collectors, including collectors selected from Reagents (D). 25

5. A collector or collector system according to any one of claims 1 to 4 characterized in that the collector system includes reagents (A) and (A), (A) and (B), (B) and (B), (A) and (C), (B) and (C), (C) and (C), and (A) and 30 (B) and (C) and in that the collector or collector system can contain any amounts of reagent(s) (A) and/or reagent(s) (B) and/or reagent(s) (C) including from 0-100% reagent(s) (A) and 0-100% reagent(s) (B) and 0-100% WO 2008/019451 PCT/AU2007/001175 - 53 reagent(s) (C), on a weight basis in any specific proportion within the weight range specified, and in any combination of amounts of the individual reagents. 5

6. A collector or collector system according to any one of claims 1 to 5 characterized in that the substituent represented by R or R' of formula I or formula II or formula III include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, isoamyl, n 10 pentyl, iso-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, m-cresyl, o-cresyl, p-cresyl, benzyl groups (-CH 2 -C 6 Hs) or combinations or mixtures or isomers of two or more of the foregoing including derivatives of and precursors of the reagents, and other functional substituents. 15

7. A collector or collector system according to any preceding claim characterized in that reagent (A) is isopropylmethylthionocarbamate, isobutylethylthionocarbamate, 20 isopropylethylthionocarbamate, including combinations of two or more.

8. A collector or collector system according to any preceding claim characterized in that reagent (B) is 25 potassium di-isobutyl dithiophosphate or potassium di secbutyl dithiophosphate or a combination of both.

9. A collector or collector system according to any preceding claim characterized in that reagent (C) is the 30 acid form of a mercaptobenzothiazole including 2 mercaptobenzothiazole or sodium mercaptobenzothiazole or combinations of both.

10. A collector or collector system according to any WO 2008/019451 PCT/AU2007/001175 - 54 preceding claim characterized in that the collector, collector system or collector mixture includes at least one or more of isopropylmethylthionocarbamate and/or isopropylethylthionocarbamate and/or 5 isobutylethylthionocarbamate, at least one or more of potassium di-isobutyl dithiophosphate and/or potassium di secbutyl dithiophosphate and at least one or more of isopropylmethylthionocarbamate, isopropylethylthionocarbamate with one or more of 10 potassium di-isobutyl dithiophosphate and/or potassium di secbutyl dithiophosphate.

11. A collector or collector system according to any preceding claim characterized in that the alkali in metal 15 is sodium or potassium.

12. A collector or collector system according to any preceding claim characterized in that the substituted ammonium ion are tetramethyl ammonium ion. 20

13. A collector or collector system according to any preceding claim characterized in that the amounts of reagents (A), (B), and (C) include from 5 to 95% reagents (A), (B) or (C), from 10 to 90% reagents (A), (B) or (C), 25 from 20 to 80% reagents (A), (B) or (C), from 30 to 70% reagents (A), (B) or (C), from 40 to 60% reagents (A), (B) or (C), about 50% of reagents (A), (B) or (C) in which the amount of reagent (A), (B) or (C) can be the same as each other or two may be the same as each other or all three 30 may be different from one another in which all of the percentages are on a weight basis.

14. A collector or collector system according to any preceding claim characterized in that the collector system 35 is 10% isobutylethylthionocarbamate, 80% sodium di isobutyl dithiophosphate and 10% sodium WO 2008/019451 PCT/AU2007/001175 - 55 Mercaptobenzothiazole.

15. A collector or collector system according to any preceding claim characterized in that the collector is 10% 5 isopropylethylthionocarbamate and 90% sodium di-isobutyl dithiophosphate.

16. A collector or collector system according to any preceding claim characterized in that the collector is 30% 10 isopropylmethylthionocarbamate and 70% potassium di secbutyl dithiophosphate.

17. A collector or collector system according to any preceding claim characterized in that the collector is 15 28.6% isopropylmethylthionocarbamate, 66.6% potassium di secbutyl dithiophosphate and 4.8% surfactant.

18. A collector or collector system according to any preceding claim characterized in that the collector is 30% 20 isopropylmethylthionocarbamate and 70% potassium di isobutyl dithiophosphate.

19. A collector or collector system according to any preceding claim characterized in that the collector 25 further includes reagent (D) in which reagent (D) is selected from Xanathates (dithiocarbonates) including Xanthogen formates; dithiocarbamates; dithiophosphates, such as anilino dithiophosphoric acid including salts, esters or the like such as anilino dithiophosphates, 30 dithiophosphinates, octyl sulphides, alcohols, hydroximic acids, salts, esters and similar; and the like including combinations of two or more of the foregoing.

20. A collector or collector system according to any 35 preceding claim characterized in that the collector includes surfactants, including anionic and non-ionic WO 2008/019451 PCT/AU2007/001175 - 56 surfactants, such as alkylamine ethoxylate containing from 15 to 30 moles of ethylene oxide and nonylphenol ethoxylate with 12 to 20 moles of ethylene oxide; other additives for other purposes including glycol ethers, 5 dispersants, foamers, processing aids, frothers or other agents promoting frothing of the aerated mixture as well as defoamers, water, particularly recycled water from the treatment plant containing impurities, such as the byproducts from the various treatments occurring in the 10 treatment plants, such as for example, xanthates.

21. A collector or collector system according to any preceding claim characterized in that the amount of surfactant added to the collector mixture and/or reaction 15 is from about 0 to about 20% by weight.

22. A collector or collector system according to any preceding claim characterized in that the pH of the pulp and collector mixture is any value up to about 13, 20 preferably from about 2 to 13, more preferably from about 7 to 11 and most preferably about 8 to 10.

23. A collector or collector system according to any preceding claim characterized in that the amount of 25 collector mixture and/or reaction added to the raw material is any amount up to about 200 grams per ton of ore being treated, preferably from about 2 g/T to about 150 g/T, more preferably, about 3 g/T to about 100 g/T, even more preferably about 3.5 g/T to about 80 g/T. 30

24. A collector or collector system according to any preceding claim characterized in that the collector mixture and/or reaction is added to the raw material as a single dose, or in two or more doses, such as in two, WO 2008/019451 PCT/AU2007/001175 - 57 three, four or more doses in which the doses can be added separately at different time intervals and/or at different spaced apart locations to one another. 5

25. A collector or collector system according to any preceding claim characterized in that the collector is added at one location within the treatment plant or at two or more different locations within the plant. 10

26. A collector or collector system according to any preceding claim characterized in that one dose of the collector or collector system is added to the grinding mill, to the rougher, to the scavenger or to any other part of the treatment plant whilst other doses can be 15 added to other parts of the plant.

27. A collector or collector system according to any preceding claim characterized in that the metal values being recovered by the present invention include gold, 20 silver, zinc, lead, nickel, platinum group minerals or copper including combinations of two or more such metals.

28. A collector or collector system according to any preceding claim characterized in that the minerals being 25 treated by the collectors of the present invention are sulphide minerals containing gold, silver, copper, lead, nickel, platinum group metals (Platinum, palladium and the like) and zinc containing sulphides and the like. 30

29. A collector or collector system according to any preceding claim characterized in that the raw material being treated by the collector or collector system includes fresh material, untreated material, virgin material, waste material, previously treated material, WO 2008/019451 PCT/AU2007/001175 - 58 recycled material, including combinations of such materials.

30. A collector or collector system according to any 5 preceding claim characterized in that the raw material includes sulphidic ores, slags, oxidized ores, transition ores, supergene ores, ores containing oxidized sulphides, sulphur containing ores including combinations of such materials. 10

31. A method of recovering at least one selected metal and/or mineral from a raw material in a froth flotation process using a collector, collector system, collector mixture, collector reaction and/or collector 15 products of a reaction of reagents comprising the steps of introducing the collector to the raw material and subjecting the raw material to a froth floatation process using a collector or collector system or collector mixture 20 and/or reaction of collectors and/or the product(s) of reactions of collectors characterized in that the collectors or collector system is capable of being used for concentrating metal values and/or minerals from ores, mineral pulps, and/or slags or other raw materials 25 containing metal and/or mineral in froth flotation processes, and in that the collector, collector system or collector mixture and/or reaction comprises at least one or more members of reagents selected from the following groups of reagents either in combination with a member 30 from the same group of reagents, or in combination with one or more reagents selected from at least one other group or other groups of reagents in which one group of reagents is WO 2008/019451 PCT/AU2007/001175 - 59 A) One or more reagent(s) of a thionocarbamate having the general formula (I) R S R-N-C- OR' 5 in which R and R' are the same or different and are selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or alkaryl groups having from 1 to 20 carbon atoms including linear or branched carbon chains and substituted 10 or un-substituted carbon atoms including being substituted with a hetero atom, wherein another group of reagents is 15 (B) one or more reagents of a dithiophosphate having the general formula (II) R S P R S-M(II) 20 in which R is the same or different and is selected from hydrogen, alkyl groups, alkenyl groups, aryl groups or alkaryl groups having from 1 to 20 carbon atoms, including branched or un-branched carbon chains and un-substituted or substituted carbon atoms including hetero atoms, and M 25 is an alkali metal selected from Group I of the Periodic Table or is an ammonium ion, including substituted ammonium ions or a cresyl, a substituted cresyl or a cresyl-containing group, and wherein WO 2008/019451 PCT/AU2007/001175 - 60 another group of reagents is (C) one or more of mercaptobenzothiazole of the general 5 formula (III) R N C-SM R (III) in which R may be the same or different and is selected 10 from hydrogen, alkyl groups, alkenyl groups, aryl groups or alkaryl groups having from 1 to 20 carbon atoms including branched or unbranched carbon chains and substituted or unsubstituted carbon atoms including hetero atoms and M is hydrogen, an alkali metal selected from 15 Group I of the periodic table, an ammonium ion, a substituted ammonium ion, a cresyl, a substituted cresyl or cresyl-containing group.

32. A method according to claim 31 characterized in 20 that the collector or collector system is in accordance with any one of claims 1 to 30.

33. A collector or collector system or collector mixture and/or reaction either alone or in combination 25 with any other material substantially as herein described with reference to the accompanying examples and/or drawings. WO 2008/019451 PCT/AU2007/001175 - 61

34. A method of using a collector or collector system or collector mixture and/or reaction either alone or in combination with any other material to extract a selected metal or mineral using froth flotation techniques 5 substantially as herein described with reference to the accompanying examples and/or drawings.