Search Documents

Promoters for Soap Flotation of Phosphate Minerals

Sep 13, 2010

Optimisation of the Advanced Automation System at Inmet Mining's PyhSsalmi Mine, Finland

Sep 13, 2010

Particle Mechanics and the Design of Cyclone Tribochargers Triboelectric separation is a dry electrostatic technique that has shown promise in several particle processing applications. A tribocharger uses contact or friction to differentially charge particles of different materials, which are then separated by an electric field. The initial tribocharging process is poorly understood, with tribocharger design and operation largely a matter of trial and error. A better physical understanding of tribocharger operation would therefore be of immense value in the optimisation of triboelectric separation processes. A combination of charge measurements, trajectory modelling and high-speed video has been used to relate charging to particle mechanics in a cylindrical pneumatic cyclone, one of the most effective tribochargers for mineral separation applications, and the preliminary results are presented here. The consequences of these observations for cyclone tribocharger design and operation, and for tribocharger design in general, are discussed.  

Sep 13, 2010

In the plumbing of vertical shafts the methods employed and equipment used, are generally made to best suit existing conditions. Undoubtedly, there is no method that can be called standard or that can be used with equal ease and success on all shafts. At the Mount Isa Mines Limited property in Northern Queensland, Australia, local conditions have presented no major difficulties to be overcome in shaft plumbing work. In fact, compared to those at many shafts, the problem has been rather simple. There are three vertical shafts connecting main mine workings, with the greatest plumbing depth for any single lift, 350 ft.Other conditions pertaining to plumbing work have been generally normal.The method we have employed is, in principle, similar to the Weisbach orientation method with a variation that does not necessitate damping of the wires to bring them to rest. Although conditions encountered have not been such that damping the wires would have been inconvenient, we feel we have saved much time and eliminated unnecessary...

Jan 1, 1940

The mechanization of the coal industry in New South Wales involved the introduction of large face and transport machines. The trend is towards still higher capacity units with .greater horsepower and it became apparent that a potential risk of damage to the hearing of workmen existed. In order to assess whether the sound levels were SUfficiently high to impair the hearing of workmen a sound level survey of all major operations in the industry was carried out by the Mining Engineering Division of the Joint Coal Board.The results indicated ·that the operations could be classified into three categories of risk, probably hazardous, of doubtful hazard due to the intermittency of the operations, and of low hazard.Legislation has subsequently been enacted requiring the wearing of hearing preservation aids in some of the probable risk operations.

Jan 1, 1974

By W Mez

The German mining industry uses different residues for backfilling and stowing. A hydraulic pipe conveying technology for these materials has shown advantages for the transportation into the mine. Pipeline conveying systems are able to bridge long distances, they save room within the underground workings and they save staff and costs. Absolutely necessary for successful use of the hydraulic conveying technology is the knowledge about the unusual non-Newtonian flow properties of solid/liquid mixtures like pastes and slurries. The flow resistance of these materials cannot be described easily by one viscosity. Owing to a yield point and a pseudo-plastic behaviour the viscosity changes with the shear rate and with the streaming velocity inside the pipe. Also these flow behaviours depend very sensitively on the liquid/solid-ratio, often so dramatically that gravimetric or volumetric dosing equipment is not in a position to control the production of backfill pastes. Quality changes of the solid raw materials (particle size distribution, density, mineralogical composition) lead to additional difficulties. The first experiences with hydraulic backfilling plants were troubled by plugged pipes, a bad backfill quality caused by unnecessarily high water content and high costs for chemical binders to solidify the backfill. The installation of viscosity controlled paste production leads to success with the hydraulic backfill technology. A development of the DMT, a bypass pipe-viscometer, has been the key technology. The system is able to analyse on-line, difficult, sticky and abrasive substances and determine their non-Newtonian flow properties. Because the system measures real physical values it is in a position to pre-calculate process relevant parameters like the pressure drop of the backfilling paste in the conveying pipeline. Newer types of the viscometer system also measure the slurry density and calculate its composition. These systems have proven a success controlling backfill paste production plants. They offer a secure prevention of pipeline plugging and a production of high quality backfill pastes with a water content as low as possible.

Jan 1, 1998

By P K. Smith, N G. Corner, R J. Ryan, D C. Arne, F P. Bierlein

The Reefton Goldfield has produced 67 t of gold from mesothermal vein gold deposits in metasedimentary rocks of the Greenland Group (Cambrian-Ordovician). The Globe-Progress deposit contributed 13.2 t (418,000 oz) of this total, predominantly from quartz veins. Recently a resource of 14 Mt at 1.96 g/t Au (27.5 t or 882,300 oz of contained gold) has been delineated at Globe-Progress in quartz vein remnants and disseminated within adjacent sedimentary rock, much of which has been locally brecciated. The breccias consist of quartz vein and sedimentary wall rock fragments set in a matrix of clay ærock flourÆ and sulphide (arsenopyrite plus minor pyrite and stibnite). Gold, closely associated with sulphide, is disseminated within the breccia. Disseminated gold also occurs in massive siltstone and sandstone adjacent to the quartz veins and breccias. Exploration drilling at Globe-Pogress, and several other Reefton prospects (e.g. Capleston, Merrijigs, Big River and Alexander River), has intersected zones of disseminated arsenopyrite carrying up to 20 g/t more gold. These mineralised sediments commonly have little or no megascopic quartz and or carbonate veining. There is little visible indication of former primary or secondary permeability for the passage of hydrothermal fluid and deposition of gold. However, porosity and permeability were formerly present in inter-granular pore spaces and microveinlets now filled with quartz, carbonate and K-mica. The Fosterville gold deposit in Victoria bears many similarities to the Globe-Progress deposit at Reefton, in terms of age, host rocks, hydrothermal alteration and mineralisation style. Many ofthe disseminated deposits in Nova Scotia, including deposits at North Brookfield and Moose River (Touquoy Zone), have similar characteristics to the Reefton disseminated mineralisation, but commonly have abundant pyrrhotite and some deposits have disseminated metal alloy grains of complex metallurgy.

Jan 1, 2000

By W C. Burton, J S. Kuszma, T O. Aspinall

The environmental impact of mining and evolving environmentallegislation has received increased attention worldwide in the last two decades (Bradfield, Shultz and Stone, 1996). The potential impacts associated with unstable spoil dumps from mine operations is the focus of concern both by the mining industry, environmental regulatory agencies and members of the public. Engineered slopes of mine spoils may be stable at the end of construction, but they can deteriorate over time. There is thus the need to increase the base of knowledge on the existing practices of spoil dump design and rehabilitation. Efficient engineering design and systematic economic evaluation of spoil dump reshaping techniques for mine rehabilitation assists in maintaining the expected standards of environmental compliance. As part of the overall approach for effective engineering design ofspoil dumps, a comprehensive, computational and efficient tool isrequired for assessing the economics and productivity of existing spoil dump reshaping practices for efficient mine rehabilitation. Such a design tool is useful in linking current spoil dump environmental management practices with engineering design planning and economic impact evaluation. This paper identifies the processes for the economic impact evaluation for existing spoil dump reshaping practices and proposed final site dump designs. Selection of an efficient spoil dump design at optimum costs will ensure operational efficiency. A case study is presented identifying economic impact evaluation in earthmoving equipment selection and the costs involved for the reshaping of spoil dumps to that of varying final site designs.

Jan 1, 2000

By A D. Campbell

Conversion of Mineral Resources to Ore Reserves requires a multidisciplinary approach and application of a number of Modifying Factors. The Modifying Factors for mining, particularly dilution and recovery in a caving mine are complex and can be difficult to determine. Cave flow modelling software is widely used for mine planning, scheduling and forecasting metal production. However, the conversion of Mineral Resources to Ore Reserves remains a difficult and subjective process and a consistent approach to convert Mineral Resources to Ore Reserves as part of the cave flow modelling process is not published in the literature. This is due to the difficulty in estimating the Ore Reserve that remains as cave stocks at a particular point in the mine schedule, the recovered tonnage and grade of the diluting material at various stages in the mine life, as well as the Mineral Resource classification of both the recovered and diluting material that forms the Ore Reserve. The key principle of this paper is the tracking of the Mineral Resource classification in the flow model used to estimate the Ore Reserves. This is critical to defining the Ore Reserve as Proved or Probable and enabling transparency in the reporting process. An approach for dealing with mineralised external dilution in the Ore Reserve estimation process is also provided.This paper outlines the approach to convert Mineral Resources into Ore Reserves developed at the Ernest Henry mine sublevel cave (EHM SLC). The same method could be used in any cave mine and applied at any stage of the mine life. The process replaces broad-brush assumptions for the mining Modifying Factors, such as dilution and recovery, as these are determined numerically as part of the model computation. This paper explains the Ore Reserve estimation method with a worked example to enable the reader to adopt the process at any caving mine. Mineral Resource classification within the block model is embedded in the cave flow model and the flow model results used to attribute tonnes, grade and the mixed proportions of the Mineral Resource classification for material extracted from each drawpoint. This information is then used to convert planned mine production into the appropriate Ore Reserve classification. Since the flow model simulation follows the mine schedule, it can be used to predict depletion and cave stocks at any stage of the mine life, and can calculate a residual block model at the end of the mine life. The accuracy of the flow model is checked by validating the forecast ore grade and metal tonne with reconciliation data from the concentrator which is also used to calibrate the flow model.CITATION:Campbell, A D, 2017. A simple and accurate method for Ore Reserve estimation and Mineral Resource depletion in caving mines, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 253–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By H Susanto, N Belluz, D Flint, A Edw

The Deep Ore Zone (DOZ) is a block cave mining operation exploiting a diluted reserve of 131 million tonnes grading 1.06 per cent copper and 0.81 g/t gold in the lower portion of the Ertsberg East Skarn System (EESS). The EESS is a calcium-magnesium silicate skarn containing in excess of 250 million tonnes of copper-gold ore, located in the Ertsberg Mining District on the crest of the Jawawijaya mountain range in the highlands of Irian Jaya, Indonesia. The EESS was discovered in 1968 where it cropped out at an elevation of 4050 metres above sea level. The Ertsberg Mining District is underlain by siliclastic carbonate and siltstone formations of Jurassic to Tertiary age. The sediments have been folded and are cut by major bedding subparallel and crosscutting structures. Intrusion of a series of igneous bodies post-dates folding and faulting. These I-type intrusions are the source for the copper-gold mineralisation found in the Ertsberg Mining District. The EESS is hosted by carbonates of the Tertiary Waripi and Faumai Formations that have been altered to calcium-magnesium silicate skarn and is situated on the southern limb of a northwest-trending syncline. The EESS is an essentially vertical tabular body with a vertical extent of at least 1200 metres and a lateral extent of up to 1000 metres. The width of the EESS averages 200 metres and locally is in excess of 300 metres. The northeast (hangingwall) contact of the EESS is a skarn reaction front in sudden contact with barren marbles. This contact coincides with a zone of localised faulting and brecciation. The EESS is bounded to the southwest (footwall) by the Ertsberg Diorite, a 3.25 Ma old intrusive. The DOZ block cave operation extends from 3040 metres above sea level to a maximum of 3388 metres above sea level, has a length of 860 metres and a maximum width of 350 metres. The DOZ is a high temperature skarn with a prograde forsterite/diopside mineralogy whose protolith is the dolomitic Tertiary Waripi Formation. The principal retrograde alteration minerals include tremolite, actinolite, serpentine, talc and chlorite. Grade is highest where bornite occurs in large dense complex intergrowths with magnetite and anhydrite. Grade has been locally enhanced in the DOZ by a late-stage pyrite-chalcopyrite hydrothermal alteration event with associated brecciation. Ertsberg Diorite along the footwall of the skarn is also included in the reserve where it is mineralised endoskarn or has been mineralised by porphyrytic or late stage hydrothermal alteration. Formation of the EESS was initiated by contact metamorphism during the intrusion of the Ertsberg Diorite with later metasomatic alteration during both prograde and retrograde phases. The bulk of sulphide mineralisation formed late in the retrograde phase. The EESS is open along strike to the northwest and down-dip with on-going exploration of these areas. Current exploration is targeting both endoskarn and porphyry style alteration and mineralisation of the Ertsberg Diorite.

Jan 1, 1999

By P W. Cleary, G K. Robinson, M D. Sinnott

Discrete element modelling (DEM) is a research tool that involves numerically solving the equations of motion of large numbers of particles. It can be very useful for investigating mechanisms that can lead to bias when extracting samples from material as it is carried on a conveyor belt or as it falls from the end of a conveyor belt. DEM is more realistic than conceptual models and mathematical models; but it is not as realistic as physical experimentation. Its primary advantages over physical experimentation are that it is cheaper and that it allows many factors to be varied while keeping other factors unchanged.This paper reviews our investigations of the performance of sampling systems by using DEM. The sampling systems investigated include falling-stream cutters, cross-belt cutters, Vezins and a device called a ætrue-beltÆ cutter, which is being developed. The purpose of the review is to explain what DEM has contributed to the theory and practice of sampling, and to indicate what it is likely to be able to contribute in the future.CITATION:Robinson, G K, Cleary, P W and Sinnott, M D, 2012. How discrete element modelling is influencing the theory and practice of sampling, in Proceedings Sampling 2012 , pp 15-20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By B Rosemberg, F Lemos, A J. B Dutra

The chemistry of cyanide solutions is complex, this complexity being responsible for the ability to act as complex-forming agents in metal dissolution processes, among them gold and silver. Such ionic species are used in hydrometallurgical processes, in particular in gold extraction and electro-plating. Due to the high toxicity of cyanide, the discard of effluent from processes and/or industries demands rigorous treatment so as to minimise its concentration. Among the conventional chemical treatment of such effluents one can mention SO2/air; biological degradation; oxidation by using hydrogen peroxide; oxidation by sodium hypochlorite, etc. However, the electrolytic recycling process is also promising for cyanide recovery and offers the possibility of recycling it to the aforementioned industrial processes. Such a process does not use additional chemicals but enables direct re-utilisation to the main process aiming at adjusting the cyanide concentration.

Jan 1, 2002

Mineralisation was identified at Gladstone Hill as far back as the late 1870s-early 1880s, shortly after the initial discovery of mineralisation at what is now the Martha Mine. Indeed, early recovery problems associated with the Martha mineralisation led to the preferred development of ore bodies within what is now the Union Hill Joint Venture tenement; ore bodies such as Silverton, Amaranth, and Union to name a few. Gladstone Hill forms the basis of the Union Hill Joint Venture, a 50:50 joint venture managed by Au-Ag Resources Ltd (a fully owned subsidiary of Otter Gold Mines Ltd), and Welcome Gold Mines Ltd (a fully owned subsidiary of the Normandy Group). The joint venture participants also operate the adjacent Martha Mine. Mineralisation of Gladstone Hill, as with mineralisation at the adjacent Martha Mine, has been interpreted as a low sulphidation epithermal Ag-Au system hosted within hydrothermally altered andesites of the lower Coromandel Group. Drilling in recent years has successfully identified extensive mineralisation associated with a number of vein sets throughout the tenement including the Gladstone Vein set, the Moonlight Lode and more recently along a north-easterly trend towards the historic Favona workings. A wide range of vein styles is apparent, ranging in character from thin stock works to broader lode-style banded chalcedonic to cherty quartz and have been interpreted as representing multiple phases of emplacement. At shallower levels mineralisation is often hosted by vein clasts within vent breccias. Visible gold is rare, with mineralisation generally associated with very fine-grained pyrite, arsenopyrite and minor electrum. Percentage levels of combined sphalerite-galena-(+/- chalcopyrite) have been intersected at depth however these have been gold poor to date. The potential for the Gladstone Hill area remains to be clearly defined as drilling to date has yet to close off mineralisation both along strike and down dip. If further drilling is successful, the joint venture partners believe Gladstone Hill could contribute significantly to the economic future of current operations.

Jan 1, 2000

Difficulties were experienced in the identification of carbonate minerals intimately associated with iron oxides in the so called carbonate ore, which occurs at depth in the Iron Duke Orebody.Determination of refractive indices by examination under the microscope using the immersion method, together with inferred chemical composition indicates that dolomite and parankerite are common constituents. Histograms of the manganese and sulphur contents strongly suggest that manganese is associated with the carbonate minerals, and that the highest sulphur assays occur near the base of the carbonate body.From the present work it is concluded that refractive indices indicate only a very approximate composition for carbonates of the parankerite type.The different carbonate minerals occur in irregular zones.INTRODUCTIONThe Iron Duke deposit is situated in the southern portion of the South Middleback Range on Eyre Peninsula, S.A., 30 miles from Whyalla. (Fig. 1).Drilling at Iron Duke revealed a large body of so called carbonate ore, which was tested in detail at cross section 1000 ft. S by three diamond drill holes, DDH.57, 67 and 78. (Fig. 2)Most specimens of carbonate ore described below were obtained from DDH 67 and 78.GENERAL GEOLOGYThe South Middleback Range is composed of two parallel ridges trending north-south. The Iron Duke orebody is situated on the southern portion of the western ridge. (Fig.1) .The rocks of these ranges belong to the Middleback Group which rests on a gneiss complex. Their age is considered to be Middle Precambrian or late Archaean.

Jan 1, 1963

By Waugh D. M

investigations have been undertaken into the flow characteristics of mineral slurries from a number of Australian metallurgical plants including Mount Isa Mines Ltd., North Broken Hill Ltd., and Broken Hill South Ltd. Experimental equipment installed for this work included facilities for continuous recording of flow rate and pressure drop and detection of sedimentation.Although the method has subsequently been described in published literature, it is believed that the investigations included the original application of a method for correlation of the flow rate and pressure drop data. This method depends on solving by graphical methods the values of the constants k, and c in the relationship EQUATION 1 where D is pipe diameter; ?P, pressure drop; L, length; and V, mean linear velocity. Discussion of this correlation also reveals why sedimentation velocity does not necessarily vary greatly with pipe diameter.INTRODUCTIONIn order to design pumps and pipeline installations for a Newtonian fluid, measurements of the fluid's density and viscosity in any of a number of instruments are sufficient. Substitution of these values in well known equations to calculate Reynolds numbers and subsequent correlation to determine friction factors are all that is required for engineering specification.As a result of work during the last decade, particularly that of Metzner and Reed (1955) and Dodge and Metzner (1959), it is now possible to design for homogeneous non-Newtonian fluids using relatively simple instrumental measurements.These methods can sometimes be applied to thick slurries which behave as if homogeneous. However, for the...

Jan 1, 1965

By Worner H. K

Education has always been a topic to rouse the interest of mining and metallurgical engineers, but the recent activities of the Education Committee of the Australasian Institute of Mining and Metallurgy 1, 2, together with the moves throughout the Commonwealth to extend the field of technological education, have made the subject a very live one at the present time. The authors have felt it would be appropriate that on the occasion of the First Ordinary Meeting for 1950, in Victoria, some contribution should be forthcoming concerning the history, present status and possible future trends of mining and metallurgical education in this State. As for the past, the time approaches when there will be none having personal recollections of the beginning of Victorian mining schools or of the men who started them. As for the future, it is obvious that rapidly expanding metal-producing and metalconsuming industries will demand a greater output of competent graduates and diplomates. The era immediately ahead seems to be bristling with opportunities, but mining educators need to temper their enthusiasm for various policies and programmes with the realisation that they are helping to train men who will be leaders 15-20 years hence when the problems of industry and trials of life generally may be very different from what they are to-day.

Jan 1, 1950

By E J. Cowan

Efficiency demands that mine geologists devote the most time to tasks where they can have the biggest effect on production. One of the most time-consuming tasks is geological interpretation of the orebody and turning this into a block model for the planning engineers.The current best practice for mines that require a geologically constrained resource model involves capturing the interpretation of geologists as three-dimensional (3D) wireframes. However, there is significant overhead in the production of valid wireframes from sectional and plan interpretations. This overhead consists of the mundane tasks of digitising polylines, then building 3D wireframes and validating them. While software can simplify this task, the current process is not the best use of a geologist’s time. Under time pressure exerted by planning engineers and the time required for modelling from polylines, geologists are forced to roll-up the presence of other elements or impurities into the interpretation and encode them in the polylines, even though it is often desirable to consider these other factors separately.While it might seem unlikely that mine geologists can produce constrained geological models without the intermediary of wireframes, the technology to accomplish this is getting closer.In this paper, the results of a trial at the Savage River magnetite mine, which is owned and operated by Grange Resources Ltd, are reported. The trial was for a ‘direct-to-block’ implicit geological modelling method. The focus was on creating a geological attributed block model from drill hole geological log data; resource estimates were not determined. The categories modelled were air, waste, low-grade ore, medium-grade ore, and high-grade ore. The block model outputs either resulted in a proportional block model (categories expressed as percentages within equivolumetric blocks) or a sub-blocked model (parent block and one sub-block), which is the preferred block model output at the Savage River mine. When compared to the traditional best practice modelling method, which takes 43 work days, the wireframe-free modelling method took only 26 hours from initial modelling, using both exploration and grade control data. An update using appended drill hole data is achievable within one day. These results represent time savings of more than one order of magnitude compared to the traditional workflow, and, as such, these figures merit serious consideration for the use of the direct-to-block modelling approach at other operations.With these time savings, geological and estimation models can be kept updated constantly; geologists will not need to set aside two months for quarterly or half-yearly modelling of the drill hole data for resource review. Such dramatic time savings will allow for the better use of highly skilled geologists, who are in short supply in the current market, and will also impact directly on downstream mining engineering workflows.

Aug 22, 2011

A real Dorothy Dix title has been selec- ted for this paper. It has the advantage, however, of being capable of being interpreted in many different ways and hence I can select my own approach. You probably are thinking that this topic would be more appropriately handled by an Accountant. I wish to make it clear at the outset that I am not skilled in the sometimes mysterious ways of Accountants - likewise that profession frequently has difficulty in pinning down economists. We have our own strange ideas about profits, marginal efficiencies, cost/benefit analysis etc. What follows is in the main a mixture of two disciplines, probably in a form that few of the purists from either side would accept. Nor do I expect the reader to accept my own prejudices. The paper is designed to stimulate thought and discussion'on the subject. Emotive words such as "profit" and "loss" make for wide differences of opinion. At the time of writing there is a surprising degree of acceptance of the viewpoint that profits in Australia are too low and one is tempted to make this point of near agreement a starting Point.

Jan 1, 1975

Total mechanisation in the Western district of New South Wales is quite a recent addition to productive methods in that State, for it was only in 1940 that the first colliery was equipped for this method of winning coal. Now almost all mines either are totally mechanised or are planning to get their coal by these means.This marked change in recent years is explained by the salient features of the industry's history. Collieries in New South Wales had generally been subjected to low selling prices forced on them by over-production and severe competition. Little money was available out of profits to purchase machinery, and returns on capital were so poor that inducement to invest money in the industry was nonexistent.The second world war brought price fixing at the already low prices. It was not until the post-war period that there has been any inducement to mechanise.Much credit for mechanisation can be given to the Joint Coal Board, a government body formed in 1948. Pursuing a broad plan for the rejuvenation of the industry, this Board, purchased large quantities of machinery for use in, mines under hire-purchase agreement. These agreements encouraged machine mining, and this fact, together with the ensuing production economies, has improved the financial position of the industry.The Board has also been instrumental in the granting of increases in the fixed price of coal, so that the industry has been given an even greater boost in the direction of mechanisation.

Jan 1, 1954

Thermodynamics of Non-Cyanide Gold Solvents The present status of the raw material base in the gold industry requires specific ways to recover gold and silver from ores. Most gold is closely associated with sulfides which require flotation followed by pressure or bacterial oxidation. The next stages of processing usually require using expensive operations for the preparation of leaching. A lot of researchers want to find a new alternative solvent for the extraction of precious metals from these products. According to the authors, one of the best ways is to use sulfur-based solvents (thiosulfate, sulfite, and their various mixtures). Thermodynamics of gold and silver thiosulfate dilution are calculated for conditions: the concentration of Au - 200 mg/L, oxygen - 3.2 mg/L, thiosulfate - 79 mg/L, OH- - 170 mg/L. the general result is the possibility of process remains under standard conditions. (erAu = = 0.035 V, ?G298 = - 29.18 kJ/g-atom ??). Silver with thiosulfate forms two strong complexes: [AgS203]- and [Ag(S203)2]3-. ?G0 = -1027 kJ/mol. The complex [AgS203]- is less stable: ?G0 = 486 kJ/mol. It should be noted that despite the high stability of gold complexes, the sodium thiosulfate may decompose to sulfite and elemental sulfur during the process, especially when heating. Gold is slightly soluble in the sodium sulfite solution, however it forms the strong complex [Au(SO3)2]3-. Depending on the concentration of free S2O32-ions, silver with sodium sulfite forms three complexes: [AgSO3]-, [Ag(SO3)2]3- and [Ag(SO3)3]5-. The dissolution speed of gold in sodium sulfite solution may be in the same range as it is during cyanidation. In this case, a practical application of sulfite process can be also used, especially for the products containing free elemental sulfur. In conclusion, sulfite-thiosulfate gold lixiviants can be used for concentrates after pressure oxidation of the cakes.

Sep 13, 2010