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In responding to why some longwall roadway development rates are different among mines, the Roadway Development Task Group (RDTG) of Australian Coal Association Research Program (ACARP) has initiated a benchmarking study to survey each longwall mine to determine the correlation between roadway development practices and roadway development performances. This paper describes a web-based relational database system which has been developed purposely to monitor the performance of Australian longwall roadway developments aimed at assessing both the physical and operational factors which could influence roadway development practices and their performance indicators. Statistical analysis of an earlier survey suggested that continuous miner units that achieved more than 1750 m were units mining two-heading development.

Dec 6, 2010

By F Rashidinejad

Iran has had an active mining sector for some 7000 years. Exceptional in terms of its mineral diversity, Iran produces 62 minerals, and is ranked among the world’s 15 most mineral-rich countries. Many people around the world know Iran as one of the major petroleum exporters. Oil and natural gas dominate Iran’s economy, and oil exports provide the principal source of income, contributing more than 80 per cent of foreign exchange earnings. Transformation of Iran from an oil exporter to an independent country to oil has been on the table for many years, even before the Islamic Revolution of 1979. Development of the Iran’s mineral industry is one of the major replacements for petroleum exports. In the last decade, Iran invested billion dollars in the mining and mineral industry sectors and to increase the added value, tried to export processed minerals instead of the raw materials. In accordance with the ‘20-year Perspective 2025’ that targeted by the Supreme Leader, Iran will be a country with the first rank in economy, science and technology in its region. The objectives over this perspective include briefly increasing annual production to 55 Mt of crude steel, 800 000 tonne of copper cathode, 1.5 Mt of aluminium, 200 Mt mineral products, 300 000 tonne of zinc and 5 000 kg of gold. These goals are achievable in normal circumstances, but concurrency of the 20-year Perspective 2025 with commencement of the UN Security Council sanctions against Iran, frustrated objectives of the perspective, at least the ones related to the mining and mineral industry sectors. This paper tries to elaborate the development programs and following challenges for the mining activities of Iran by 2025.

Nov 22, 2011

By D David

Clearly a plant designed only to treat average ore at the nameplate rate will fail to achieve nameplate in any typical year. To insert the necessary capability to achieve nameplate it is common process engineering design practice that plant must be able to treat an ore with 80th percentile value (hardness or competence values for example) at the nameplate rate. In the authorÆs experience, apart from a couple of notable cases, this has been applied reasonably well as a principal, and with widespread success. However, in a number of recent instances it became clear that the use of the 80th percentile number would have resulted in significant under design of the plant. This paper makes the case that the 80th percentile, as a principal, has can have serious flaws and its use needs to be assessed on a case by case basis. The discussion in this paper is the first step in developing a new design principal, and the associated methodology for selection of a design value, that will ensure plants are designed to achieve their nameplate capacities.CITATION:David, D, 2013. Is an 80th percentile design point logical?, in Proceedings MetPlant 2013 , pp 6-12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By J-T Zhu, Q-Y Tu, S-L Kong, L Wang, Y-P Cheng, H-Y Liu, Q-L Yang

China is the largest coal-producing country in the world, while the geological conditions of deep coal mining are extremely complicated with high ground stress, high gas pressure and low permeability, which results in the difficulty of gas drainage and aggravation of gas explosion and coal and gas outburst disasters. Co-extraction of coal and gas is an effective method to eliminate coalmine gas disasters and realise the safe exploitation of coal and efficient gas drainage at the same time. This concept is widely accepted by the main coal-producing countries around the world, while the concrete definition of co-extraction is vague and not unified, and there is little accurate theoretical support for co-extraction of coal and gas, which makes it hard to determine efficient gas drainage methods correspondingly according to the features of coal seams in a comprehensive and systematic way. Based on theoretical analysis, laboratory test and field observations, basic thoughts and specific definition of co-extraction of coal and gas were put forward after analysing the occurrence characteristics of coal seams in China. We obtained the mechanism of mining-enhanced permeability and established the corresponding theoretical model, which is the process of fracture network formation through opening recovery of the original fractures and new fractures produced by unloading damage. Based on the core idea of ‘mining-enhanced permeability’, engineering approaches of ‘unloading by boreholes drilling’ for the single coal seam and ‘unloading by protective seam mining’ for the coal seam group were proposed to realise safe and efficient co-extraction of coal and gas. Meanwhile, combined with engineering practice, we put forward the construction principle of coal exploitation and gas drainage system in different coal seam occurrence conditions. The above methods were applied successfully in the Tunlan coalmine in Shanxi Province and the Panyi coalmine in Anhui Province, which had established the ‘underground-surface united’ spatial gas drainage modes, and could ensure safe and efficient co-extraction of coal and gas in the outburst coalmines.CITATION:Cheng, Y-P, Wang, L, Liu, H-Y, Kong, S-L, Yang, Q-L, Zhu, J-T and Tu, Q-Y, 2015. Theory of safe and efficient co-extraction of coal and gas and its applications, in Proceedings The Australian Mine Ventilation Conference, pp 79–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By G T. Kukla

A Seam deposit User oriented Mine Planning System (SUMPS) was developed by The Broken Hill Proprietary Company Limited (BHP) at its head office in Melbourne. It is one of the computer mine planning systems developed by the Corporate Data Processing (CDP) section of BHP. To date it has been employed in the feasibility study of four coal prospects for the BHP Group, including Gregory in central Queensland û Ham and Van Hoorn (1978). It was also used in detailed short term mine planning for Gregory. A recent application was in the feasibility study of Saxonvale, a multi seam coal deposit in New South Wales with seams up to 20 m thick. The other two applications of SUMPS were also on thick multi seam coal deposits. Development of programs for the underground subsection of SUMPS is continuing. SUMPS was developed and implemented on mini computers with graphics and plotting peripherals. The company's philosophy towards computing is one of centralized development and project planning, with transfer of hardware and software to site once the mine becomes operational. Support of the site's system continues from head office which is continually involved in development of SUMPS and issuing revision updates to sites. The users, as well as programmers, were mostly geologists and mining engineers. This helped to ensure rapid, successful implementation. The broad approach of this system was to use interactively the specialist skills and interpretative abilities of the user mining engineers and geologists with the data manipulation abilities of the computer. It is an integrated system which covers geological exploration, deposit modelling, mine planning and production scheduling. An important feature of the system is that the user has full interactive control over each function through a graphics terminal where applicable.

Jan 1, 1980

By E Ah Mu and C R Lilley, A D. Campbell

Cave propagation is a complex process due to interacting variables such as mine geometry, rock mass heterogeneity and complex structural networks and stress fields. The Ernest Henry sublevel cave (SLC) is directly below an open pit, which provided an opportunity to observe and measure rock mass failure as the cave initiated and propagated through the pit wall. This paper describes interaction between the open pit and SLC as well as rock mass failure mechanisms observed from the start of the SLC to surface breakthrough.Cave propagation and slope failure mechanisms were found to be governed by intermediate structures, while the cave shape was largely controlled by cave-scale faults. The open pit, production-level geometry and production draw strategy were also important factors for cave and subsidence growth. Cave propagation was episodic and asymmetric in shape due to the orientation and relative position of geological structures, combined with the effects of the increasing SLC geometry and drawdown from the underlying production levels. The precursors and failure mechanism of a 2.5 Mt wall collapse are also reviewed in detail.Cave growth was simulated using a 3D, non-linear, discontinuum finite element model coupled with Newtonian Cellular Automata. Model results are compared to field observations and monitoring data to determine the accuracy of forecasts and compared models versus actual rock mass response during cave propagation.CITATION:Campbell, A D, Ah Mu, E and Lilley, C R, 2016. Cave propagation and open pit interaction at the Ernest Henry Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 311–318 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By R Cunningham

The E26 Lift 1 North Project took 37 months from the approval on 1st January 2019 to the commencement of production on 1st March 2022. This was five months ahead of the feasibility plan. When compared to the previous E48 Block Cave construction 12 years prior, which was of a similar size and design with ten extraction drives, crusher and conveyors, the E26 Lift 1 North project has been delivered at 29 per cent less capital cost. Key metrics achieved by the project include 12.7 km of development, 240 km of production drilling for drawbells and undercut blasting, 107 drawbells fired ready for production as well as only three Lost Time Injuries compared to 16 during E48 construction. The Lift 1 North Project Team has established a significant point of difference with the delivery being completed by the ‘Owners Team Model’ not Lump Sum or Turn-key. E26 Lift 1 North is now supplying the Northparkes processing plant for the next eight years. This paper discusses major milestones achieved throughout the process, modifications to processes from previous block cave construction at Northparkes as well as novel approaches to work to achieve the successful delivery of the project.

Mar 29, 2023

Recovery of Tantalum Capacitors from Waste Printed Circuit Boards Using a Pneumatic Separator

Sep 13, 2010

By J Lapwood, S Pal, M Pascoe

The devastating failure of Dam I at the Corrego do Feijao iron ore mine near Brumadinho in Brazil on 25th January 2019 left at least 270 people dead or missing. In the immediate aftermath of this event, many mining companies commenced reviews of their tailings and water storage facilities (T&WSFs), and Rio Tinto was no exception. Rio Tinto has an interest in over 250 T&WSFs across 47 sites in 13 countries as owner-operator, as managing JV partner, and through non-managed partnerships and other ownership arrangements; T&WSF experts from Rio Tinto’s Surface Mining Centre of Excellence visited the sites in order to complete Technical Risk Reviews of each facility. These reviews looked beyond the day-to-day operational aspects of T&WSF management, and the site’s compliance with local regulations and Rio Tinto’s internal D5 Standard – Management of tailings and water storage facilities, in order to provide a strategic, second line of assurance perspective. The reviews focused on design and construction; operational controls; risk control framework; and competencies and capabilities of personnel involved in the design, operation and closure of the facilities. Additional activities were carried out in parallel with these reviews, including the development of a consistent approach to dam break studies; the public disclosure of information on Rio Tinto’s tailings storage facilities and their management; and contribution to external programs such as the initiatives being co-ordinated by the International Committee on Mining and Metals. This paper provides an overview of the tailings and water storage assurance work undertaken by Rio Tinto’s Surface Mining Centre of Excellence Tailings Validation Taskforce to date; work that will continue to improve governance and assurance for all of Rio Tinto’s T&WSF.

Jul 1, 2021

Delhi Australian Petroleum Ltd., acting as operator for the joint interests of Delhi and Santos Ltd., has been engaged in petroleum exploration in the western Great Artesian Basin since 1958.Extensive airborne magnetometer, gravity meter, reflection and refraction seisomograph, and surface geological surveys have been carried out. Results of the surveys have considerably altered the concepts of the geology of the area.Seven exploratory wells have been drilled in the area. Results of the drilling have established the presence in the subsurface of previously unknown Paleozoic sediments which are capable of generating hydrocarbons.Production of oil or gas has not been achieved, but each phase of the exploration programme has resulted in progressively establishing the basic conditions necessary for the discovery of commercially profitable accumulations.INTRODUCTIONDelhi Australian Petroleum Ltd. commenced operations in Australia in 1958. They have subsequently been engaged in systematic exploration for oil and gas, acting as operator for their partner, Santos Limited. The methods and techniques employed are those used throughout the petroleum industry. The results of the exploration programme contribute to a better understanding of the basic geology, and concomitantly a firmer analysis of the petroleum producing potential, of the western Great Artesian Basin.Each phase has progressively enhanced the gross geological interpretation of the area with regard to favourable conditions for the generation and accumulation of hydrocarbons, but the stage has not been reached where productive potential is definitely established.Exploration status in 1958Basin configurationIn 1958 knowledge of the pre-Jurassic stratigraphy of the geographically defined western Great Artesian Basin...

Jan 1, 1964

This paper considers three aspects of cemented fill practice and research in Mount Isa. Firstly, an account is given of the use of Portland cemented hydraulic fill, considering mainly the role and specifications of the fill used but including û brief description of fill preparation and placement. Data resulting from a Portland cemented hydraulic fill sampling, curing and testing campaign covering about 18 months of operating practice are presented, analysed and discussed. These yield information indicating the mode of operation of a fully-automated fill preparation station, as well as a means of comparing field and laboratory strength results. A technique with potential for use as a fill quality control without actual strength testing is also described. Results of a fill research program conducted by the author in Mount Isa since early 1968 are presented, involving both Portland cemented hydraulic fill and alternative, cheaper, additives for cementing hydraulic fill.

Jan 1, 1971

By B W. Riddol1s

The 1983 Energy Plan calls for an increase in North Island coal production from both underground and opencast sources from the 1982/1983 production of 843 000 tpa to approximately 3.4 Mtpa within the ten year period to March 1993. This increased production is scheduled to come from the following sources: Huntly West No 1 underground mine reaching full production of 1.26 Mtpa. Huntly East underground mine increasing production to 750 000 tpa. The proposed new Huntly West No 2 mine producing 100 000 tpa in its first year of operation û 1992. The proposed Ohinewai opencast producing 920 000 tpa for supply to the steelmaking plant at Glenbrook, replacing Weavers opencast which will be worked out in 1990. Rotowaro opencast producing at 220 000 tpa (currently being achieved). Two additional sources of supply which are not scheduled to begin production for at least ten years, and both of which have been designated for coal fired thermal power generation, are the Maramarua and Mokau coalfields. It was originally envisaged that development of both coalfields would be a combination of underground and opencast mines. The form of development is yet to be confirmed by detailed feasibility studies. The location of the Maramarua, Ohinewai (Waikare Coalfield) and Mokau deposits is shown on Figure 1. Worley Consultants Limited, in conjunction with their partners Rheinbraun Consulting GmbH (Germany) and Longworth McKenzie Pty Limited (Australia) have been involved with investigations and mining assessments for the Maramarua, Mokau and Ohinewai prospects. The Maramarua and Mokau studies form part of the New Zealand Coal Resources Survey programme of updating information to the Pre-Feasibility Mining Assessment level before proceeding to detailed feasibility studies. The Ohinewai study was commissioned directly by Mines Division to investigate the feasibility of mining coal by 1989 before reserves at Weavers opencast are depleted. This paper describes typical studies which are now being commissioned by Mines Division to investigate large-scale mining development and the effect geotechnical-conditions may have on coal recovery. The magnitude of these projects is reflected in the proposed outputs û up to2 Mtpa from individual mines û and the introduction of new continuous mining systems for both underground and opencast mines on a scale which has not previously been contemplated.

Jan 1, 1984

By K Niyomjinda, B Etschmann

Chatree Gold Mine is currently the only modern day gold mine operating in Thailand, and is situated approximately equidistant from Chiang Mai in the north and Bangkok in the south. Environmental guidelines set by the Thai authorities require Chatree Gold Mine to achieve a Total Cyanide level of 20 ppm or less in the process plant discharge slurry stream prior to release into the tailings storage facility. This paper describes both the initial difficulties faced in achieving compliance on this limit utilising the conventional INCO SO2/Air cyanide destruction system and the subsequent process improvements initiated to both the leaching process and the standard INCO process to achieve the current compliance levels of approximately 99/100 shifts. Improvements were focussed on the dual aspects of reducing the formation of WAD cyanide and ferrocyanide species in the leaching circuit coupled with process changes to improve removal of the ferrocyanide species from solution during the cyanide reduction stage.

Jan 1, 2004

Underground Mine Drainage may be conveniently divided into two operations:(a) Collecting and transporting drainage water to the pump eastern.(b) Elevating water to the surfacc by pumping.This short paper describes a system which automatically performs operation "a" and which has been developed on the South mine at Broken Hill, under the supervision of the mine foreman, Mr. F. McDonell. Operation "a" does not come under the heading of "subsidiary mine" drainage.SUMMARY(1) All drainage waters are collected by gravity flow into sumps.(2) Automatic control boxes operate syphons which transfer water from level to level to pump cisterns or to feed water service.EQUIPMENTSyphon Control Boar - Constructed of 10 ft. x 2 ft. oregon timber, suitably bolted together and equipped with a Bailey's cistern valve, with copper ball float control, and 12 in. pipcs and fittings forming a syphon (Fig. 1). One of these boxes is placed on each level at the shaft.The valve and float are so arranged that when the float is up (ie, box full) the valve will be fully open, and when the float is down (ie, box empty) the valve is closed. The vertical range between the cxtreme positions can be altercd by lengthening orshortening the adjustable arm of the float. The ideal valve is one...

Jan 1, 1927

ABSTRACTMechanised cut and fill stoping in the Racecourse orebodies between II and 9 levels was started in 1964.Five stopes are in progress over the two level interval, extracting the full strike length (600-2,000 ft) of each orebody without transverse pillars.Each stope is served by a central 10 ft by 12 ft service intake ventilation raise and an 8 ft by 8 ft return air raise at each end of the stope. Each stope is divided into two sections for drilling. firing. mucking, and fillingto maintain steady production. All equipment is kept in the stope for one level lift stoping. Gardner-Denver 2 boom jumbos are used for uphole drilling and Wagner ST 5 Scooptrams for loading and transport to ore passes located in the footwall of the orebody. A Wagner PTIO is used for materials handling and scaling of the stope backs.Mill tailings, after one stage of cycloning are used to fill the stope, one section at a time. About 80 per cent of the water is removed by decantation while the remainder percolates through hessian-covered pipes and boxes.The ore is passed to 11 level where it is hauled by the 3 ft 6 in. gauge train to the tipple at the shaft area. The ore is crushed underground before hoisting to the surface.A performance of about 100 ton/manshift is achieved by the drilling, blasting, and mucking crews in the stopes.

Jan 1, 1968

By S C. Dominy

Various styles of gold mineralisation pose problems during sampling because of their complex gold grade distribution and presence of coarse gold. Effective sampling and sample preparation forms the basis of resource estimates. The design of a sampling and assaying protocol must be based on a thorough understanding of the mineralisation in question, which should include consideration of gold particle size and mass distribution. The proportion of coarse gold within samples has a profound effect on the requirements for sample preparation and assaying. Choice of preparation procedure and assay type is of critical importance if sampling errors are to be minimised. Traditional fire assays, using small charge sizes, often understate assays gained from large charge sizes and techniques such as screen fire assay and LeachWELL. Proper application of the Theory of Sampling reduces errors during collection, preparation and assaying. A quality control/quality assurance program must be implemented and critically assessed. A case study from the Ballarat mine is presented, which is characterised by substantial quantities of coarse-gold hosted in quartz veins. Diamond core drilling is the key input into resource delineation. A number of different sampling and assay options have been trialled over the recent project history. The current sampling protocol utilises whole drill core, using LeachWELL assays after logging and photography.CITATION:Dominy, S C, 2017. Sampling coarse gold-bearing mineralisation – developing effective protocols and a case study from the Ballarat mine, Australia, in Proceedings Eighth World Conference on Sampling and Blending , pp 71–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By A Hollweg, K H. Esbensen, M Lischka

Two new splitter designs for intercepting moving streams of matter are presented, the variable cross-stream splitter (vCSS) and the rotary stream splitter (RSS), which are intended for implementation in a fully automated modus. The vCSS facilitates obtaining up to three subsamples with different splitting ratios from automated laboratory flow paths, while the RSS divides the intercepted sample into 16 equal analytical aliquots. The splitters can process a wide range of dry, granular and free-flowing materials (<5 mm). The required weight for each subsample can be set without mechanical adjustments in the case of the vCSS. Typical applications are subsampling/splitting for X-ray fluorescence pelletisation (or fused beads) or splitting for average shift composite sampling or grain size analysis. The vCSS combines the advantages of riffle splitting (three user-defined subsample masses) with miniature bed blending and can accept up to 15 kg in total incoming sample mass. In practice, the automated vCSS can deal with unlimited ingoing mass fluxes, while the RSS is designed to operate at a user-defined fixed subsampling rate (1/16th in the tested version). Both splitters have the potential to be optimised and evaluated according to an application/user-defined total sampling error (TSE) + total analytical error (TAE) threshold. Both splitters were tested under adverse conditions and with compositions involving three components with properties representing typical mass fluxes and components concentrations in industrial and technological systems: phosphate concentrate 89.00 per cent (<500 µm), slag ten per cent (>2 mm) and glass spheres one per cent (750–1000 µm). The slag particles vary widely in particle shape, aspect ratio and surface roughness, while the glass spheres are extremely prone to bouncing and segregation (spillage). This test system is extremely difficult to split and thus constitutes a realistic worst-case scenario. While the vCSS does not comply strictly with Theory of Sampling demands for correctness, both splitters may well be able to deliver fit-for-purpose representative results if/when tested properly. Average relative mass deviations ranged from 1.89 per cent for phosphate concentrate (relative standard deviations of 20-fold repeated splitting) to 4.72 per cent for glass spheres and 13.04 per cent for slag. For the RSS, the average replication experiment splitting variation was 2.89 per cent for phosphate concentrate, 4.82 per cent for glass spheres and 11.1 per cent for slag. Both new automated online splitters would therefore appear to be able to be tuned to fit-for-purpose representivity (defined here as maximum relative reproducibility <5 per cent) for many non-extreme materials; however, it is always imperative to test every new type/class of material empirically. There is a wide commercial potential for important materials and commodities sectors, including food, feed, drugs (pharmaceutical), secondary raw materials, recyclates, agricultural products and seeds.CITATION:Lischka, M, Hollweg, A and Esbensen, K H, 2017. New online/atline splitter designs for laboratory automation – feasibility results, in Proceedings Eighth World Conference on Sampling and Blending , pp 159–166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By M Wortley, R Morrison, T Rivett

The tracking of ore through process hold-ups such as stockpiles has been traditionally been difficult to achieve. The inability to pinpoint the exact source in the mine of material that is feeding a processing plant has led to inefficient mine-mill reconciliation processes. In addition, a lack of understanding of the behaviour of ore in process hold-ups such as bins and stockpiles often leads to poor predictions of plant performance and to poor reconciliation of this to the orebody.This paper reports on two short case studies. One case study addresses tracking ore from various parts of two mines to the concentrator. The other follows synthetic particles through the coarse ore stockpile. Both studies use radio-frequency identification (RFID) tracer technology. The paper concludes by discussing general strategies for implementation of such concepts into mine-mill metal accounting and reconciliation systems. As shown in this paper, reliable ore tracking systems will allow much more effective mine-mill reconciliations as well as the ability to model process hold-ups with regard to size by residence time distributions. This should, in turn, allow metallurgists to have a better understanding of the size and grade of material that will report to the plant at different process hold-up (eg stockpile) conditions.

Jan 1, 2009

By S M. C Verryn, K Deysel

In heavy mineral sands ilmenite, rutile and zircon are present in economic concentrations. These minerals are important sources of Fe, Ti and Zr for various industrial uses. The beach sands of northern KwaZulu-Natal, along the Zululand Indian Ocean coastline in South Africa, have been mined for 30 years. The various processes involved in mining and processing these minerals have been controlled by time-consuming and labour-intensive analysis methods which, in some cases, can be replaced by X-ray powder diffraction (XRD)-Rietveld analysis. Heavy minerals are concentrated in the plant to produce a heavy mineral concentrate (HMC). The heavy mineral extraction plant is controlled and informed of the proportions of minerals in the HMC according to their magnetic susceptibility. The different fractions are called magnetic, paramagnetic and non-magnetic fractions and quality control is based on their magnetic fraction weights combined with X-ray fluorescence (XRF) elemental analysis. This current quality control process is very time consuming and labour intensive. We have aimed to show that we can, by XRD, identify and quantify all the minerals in the HMC and also in the magnetic separations. These results are then compared with results obtained by Mineral Liberation Analyser (MLA) as well as with the results from the physical separation. It was possible to detect all minerals present in the material by XRD and use the Rietveld method for a full bulk mineral quantification. A maximum of 15 minerals can be included in the Rietveld refinement due to computational restraints. Major minerals detected are rutile, ilmenite and zircon and minor minerals are quartz, epidote, anatase, amphibole, monazite, magnetite, titanite and augite. The XRD and MLA results correlate relatively well and detailed results will be presented for HMC and magnetic fraction samples. Small differences were observed for some minerals due to the different ways in which minerals are detected or due to preparation methods within each method. Rutile seems to be more abundant in the XRD analysis and the detection of Anatase is possible by XRD, but not MLA. Leucoxene (consisting of mainly microcrystalline anatase, rutile and titanite is not detectable by XRD since it is not a mineral, but ilmenite alteration phases are observed instead. There is, however, a correlation between anatase, titanite and rutile detected by XRD and leucoxene analysed by MLA.

Jan 1, 2008

By Met B. E

During the operation of the Parkes process of desilverising, and in the earlier days of the continuous process, gold and silver were removed separately from softened lead bullion. Gold was removed in the Parkes process by a selective zincing, and -in the continuous process by treatment with zinc in a special de-golding kettle, in each case a crust being obtained carrying the gold and a small portion of the silver. Actually the process could have been more correctly termed a de-copperising process, on accountof the relatively large amount of this metal present, and its affinity for zinc, which caused it to enter the crusts produced.The crust was treated in reverberatory furnaces, where the bulk of the copper and zinc was removed in by-products, and the resulting "gold bullion" cupelled to give adore bullion containing approximately 2,000 ounces gold per ton.For the purpose of parting this dore, a small Balbach-Thum plant of 11 cells was used, and once each six months a short campaign was conducted on the accumulated metal.With the development of the process of de-copperising smelter bullion by means of sulphur, when a bullion averaging about .004% copper was constantly available for refining, the need for a separate de-golding process disappeared.The de-golding kettle of the Continuous Process...

Jan 1, 1937