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The Porgera gold deposit in the Papua New Guinea highlands contains about 387 tonnes of gold. The results of its exploration show the benefits of persistence and commitment to this difficult deposit. The mineralization consists of a complex intermix of auriferous and argentiferous sulphides, gold tellurides and free gold as disseminations, veins, stockworks and breccia matrix. Its deposition was structurally contolled within a system of mafic diorite intrusions and adjacent sediments. Two styles of alteration accompany the mineralization. Gold grades vary erratically throughout the deposit. Over a period of 22 years nine phases of exploration have been undertaken by six companies or consortia of companies. Surface rock chip sampling, geological mapping followed by scout and systematic grid diamond drilling have been the most successful exploration tools. Exhaustive metallurgical process investigations and economic evaluations of mining options have been invaluable in guiding the exploration towards defining the ore body. Impetus was given to the project during times of flagging enthusiasm by several important discoveries and a breakthrough in the metallurgical processing approach. The discovery of high grade ore deep in Zone VII in 1984 turned this marginal deposit into a potentially very large gold mine.

Jan 1, 1987

By Davey P. T, Tsambourakis G

Mineralogical analysis of supergene sulphide ore recovered from areas close to the underground workings at the abandoned Mutooroo (South Australia) mine shows that the original sulphide minerals have undergone substantial alteration. The cause of this alteration is believed to be contact with the highly saline, acidic mine water. The copper is now present as a sulphide that can best be described as a copper- and iron-delicient chalcopyrite, CuxFeyS2, where in most cases x < y. The values of x and y vary from point-to-point within each grain.Leach tests under a variety of conditions show that dissolution of the copper from the supergene sulphide ore can be readily achieved, particularly when compared with the behaviour of Mt Isa chalcopyrite concentrate. For the supergene sulphide ore, an increase in the acidity and the iron(lll) concentration of the leachant re ults in an increase in the rate of copper dissolution.The results are briefly discussed in terms of the experimental in-situ leaching operation at Mutooroo, South Australia.

Jan 1, 1986

By R Halatchev

Production scheduling optimisation in open pit gold mining is a complex problem as it is driven by economic criteria reflecting particular economic interests of the concerned parties in the mining business. The contemporary organisational forms of mining, such as owner-operator and contract mining, are a good example of this relationship. These forms are complex and contradictory by nature as the contractor aims to get more waste at the beginning of mine exploitation in order to make more profit with favourable discounting effect over time, while the owner-operator aims to mine less waste at the beginning, which is a precondition for implementation of the mine planning principle of waste deferment and maximising the net present value (NPV) by accounting for the time value of money. Both forms are vital for the successful performance of the Australian mining industry as their competition is a powerful driving force of the market-oriented national economy.The present paper offers a new vision about the economic effectiveness of contract and owner-operator forms in surface gold mining through the prism of a novel production scheduling approach with a multistage stabilisation of the mining rate that implements the mine-to-market concept of modelling. The comparison of the forms is demonstrated with a case study that reveals the specific features of the new scheduling approach and the benefits of its implementation in the exploitation of Australian gold resources.CITATION:Halatchev, R, 2013. Owner-operator versus contractor production scheduling - a vision for the effective exploitation of Australian gold resources by surface mining, in Proceedings World Gold 2013 , pp 255-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By R M. Lonsdale, M D. Goodz

"With an ever-increasing dynamic business environment, successful stakeholder engagement is becoming more fundamental to achieving desired outcomes in today’s mineral resource industries. It is imperative to be proactive in correctly identifying all stakeholders and initiating early contact. This builds trust relationships, which are essential to ensure future decision-making processes are streamlined.Often neglected is a company’s obligation to select the correct team to represent its values and mission. The company requires representation that demonstrates an understanding and commitment to its operations and people, the safety and health of the community and environment, and most importantly, represents the decision makers. Stakeholders need to believe that the engagement process is genuine and that the company representatives are aligned towards targeted outcomes that will benefit all stakeholders in some way.Among others, stakeholders include shareholders, staff, families, community, service and supply providers, regulators, land managers and the political/financial framework. Depending upon the mineral product, stakeholders may include ports, international offtake clients and those along the route. New stakeholders continually evolve during mine life, and the engagement process requires an investor–community–public relations (IR/CR/PR) team to anticipate change and actively scan perception and chatter.Successful communication is more than delivering a message; it is about engaging stakeholders and confirming the feedback loop to ensure the correct message is communicated and the relationship is strengthened.The nature of the mining company’s branding and the public’s perception of company intentions will dictate whether there is willingness to allow the company to follow its desired path. This in turn controls the company’s most scarce resource – time. Timing is fundamental to achieving targeted outcomes with minimal cost and delays, marketing in a peak cycle and acquiring critical capital for development and growth.Branding and stakeholder engagement effectively controls and extends to the company its social licence to operate.CITATION:Goodz, M D and Lonsdale, R M, 2016. Stakeholder engagement – who are you, what do you stand for and why? In Proceedings International Mine Management Conference, pp 239-248 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

Suggestions have been made at various times that there may be a recurrence of lodes similar to those at Kalgoorlie in the country to the south of the Golden Mile, but, so far as is known, there has been no geological evidence to support these suggestions apart from the possible extension of the younger quartz-dolerite greenstone in this direction.Geological mapping carried out by the writer in the Coolgardie district in 1946, provided some additional geological evidence to support this claim, and the ideas then held have since been expanded and are now considered to be sufficiently advanced to present them as concrete suggestions. As will be seen from the following pages, the critical area for lode prospecting is Hannan's Lake, where the basement rocks may include younger quartz dolerite greenstone, which, although perhaps distributed over a smaller area than at Kalgoorlie, could, on structural grounds, have a similar fracture system and similar ore deposition.There is little need to stress the importance discoveries in this area would have in prolonging the life of the field, and stimulating the post-war gold mining revival.Previous Work: Only the publications having a direct bearing on the preparation of this paper are given in the list of selected references, but the writer is very conscious of the fact that much other geological work has been carried out in the Kalgoorlie district since its discovery, by the W.A. Department of Mines, by mining companies, and others, all of which has contributed to the present knowledge of the field, and acknowledgment of the value of this work is given herewith. In presenting the suggestions in this paper a broad structural control of ore deposition is assumed, but this has already been established in other parts of the goldfields of Western Australia, including adjacent areas. In the early nineteen thirties, the Western Mining Corporation commenced work on the basis that there was a close relationship between geological structure and auriferous ore deposition, and a similar approach was first made by the Geological Survey of Western Australia in the South Yilgarn in 1935. These ideas were further developed during later surveys, particularly in the North Yilgarn and the Mount Margaret Goldfield.During the Coolgardie Survey in 1946, broad structural mapping was done in greater detail than before, and the structural ideas were implemented and further developed, leading to some success.Other work to which particular acknowledgment is given is that of Stiltwell, Gustafson and Miller, Forman, Prider and Finucane, at Kalgoorlie, and that of Honman in the Kalgoorlie-Coolgardie district, references to which are given at the end of this paper.Valuable constructive criticism of this paper has been given by Professor E. de C. Clarke and Dr. R. T. Prider, of the University of Western Australia.

Jan 1, 1950

By A G. Mitchell

Stream sediment geochemical analyses were collated from open-file mining company reports and assembled in the REGCHEM computerised database at the Institute of Geological and Nuclear Sciences Limited. The database operates on an IBM-compatible PC microcomputer using an application programmed in dBASE IV and termed GEOEXPL. By August 1992, data for 6383 stream sediment samples from 6335 different sites in the Coromandel Peninsula region (Hauraki Goldfield) were entered, giving a total of 29 292 separate elemental analyses. Preliminary statistical analysis using PROBPLOT on a set of data collected by AMOCO from the Mahakirau-Whangapoua area shows that these data are a complex mix of subpopulations related to mineralisation and different source rock types. Thresholds of 37 ppm copper, 31 ppm lead, 112 ppm zinc, and 2.3 ppm molybdenum, defmed by arithmetic models for the combined data set, separate the individual element sets into 'first order anomalous/lesser anomalous and background' subpopulations as follows: copper five per cent/95 per cent, lead five per cent/95 per cent, zinc one per cent/99 per cent, and molybdenum 15 per cent/85 per cent.

Jan 1, 1992

By H Peiming, W Sakurai, Y Matsuhisa, H Shimazaki, Y Fukahori

Oxygen and carbon isotope mapping of hydrothermally altered wall rocks was applied to the blind ore prospecting of skarn Pb-Zn deposits in the Kamioka mining district, centralJapan, where the wall rocks consist of heterogeneous rock units. The results (d18OSMOW of -1.1 to +17.3ë and d13CPDB of -5.0 to +4.8ë for limestones, and d18OSMOW of -0.8 to +12.5ë for silicate rocks) show isotope zonations of the wall rocks with depletions in heavy isotopes (18O and 13C) toward the centre of mineralization. The isotope zonations likely formed by interaction of migrating thermal waters with the wall rocks during the mineralisation. The heavy-isotope depleted zone, which indicates higher temperature or higher water-to-rock ratio of the system, occurs in the footwall of a fault, indicating that the fault played the role of main conduit of the ore-forming fluids. A heavy-isotope depleted zone was also found in an area, where significant mineralisation had yet to be identified. Recent drilling in this area has intercepted a zone with a grade of 16.0% Zn, 0.8% Pb, and 35g Ag per metric tonne at a depth of about 360 m.

Jan 1, 1995

Most mines in the Bundamba, North Ipswich, and Rosewood districts of the West Moreton coalfield of south eastern Queensland have installed washing plants during the last five years. Many problems were encountered in their installation, including the small size of washing plant required in many cases, the economical minimum ash content under present and future market requirements, production from a one-product washbox of large and small coal of quality to satisfy both markets, measures to avoid adding unnecessary moisture to the washed slack coals, and excessive middlings in some coals or soft clay in others.INTRODUCTIONIt was fortunate for Brisbane, which was to become the capital of a new State, Queensland, in 1859, and grow into a city of over half a million people by the time of its centenary, that coal was found in abundance almost on its doorstep near Ipswich, the first mine being opened at Redbank in 1843. This was followed by the opening of many more mines in that district and, some 40 years later, in the nearby Rosewood district where high-volatile gas coal was produced (Fig. 1). These discoveries ensured a supply of reasonably priced coal (currently about 85/- per ton delivered) in Brisbane, but the quality is inferior to that of other coals mined in Queensland beyond economic range of Brisbane.Various factors led to an increase in the average ash content of the West Moreton coals during and after the war. Between 1940 and 1952 the gasworks coals rose in average ash from 13 8 per cent to 23·9 per cent and the powerhouse coals from 17·1 per cent to 27·1 per cent. This drift was arrested by the installation of 28 screening and picking plants from 1952 onward, but it became obvious that mechanical cleaning of the coals was essential due to the competitive market for coal and the worsening quality of reserves.

Jan 1, 1963

By M Vendrup, T C. Christensen, C Dube

The adsorptive and granulate forming MetClean™ process has been used at many locations in Northern Sweden, Norway, Denmark, France, Spain, Mongolia, Japan and Australia. It has been pilot tested and used in full scale treatment plants to remove metals from:mine watersleachate from solid waste in incineration flue gasleachate from fly ash damsleachate from landfill and waste ponds.The following paper provides details of pilot and plants tests on the effectiveness of MetClean™ in removing arsenic, antimony, barium, cadmium, copper, molybdenum, nickel, radium, uranium, vanadium and zinc. Results show that MetClean™ may reduce the concentration of these metals in treated effluent water to the one part per billion (ppb) range.The paper also finds that, for specific metals, the optimal adsorption condition depends on the:pH levelmolar relation between the specific targeted metal and the addition of iron (II) or manganese (II)type of oxidation agentssalinity levelpresence of other metals.The most effective pH level varies according to the targeted metal but falls within the pH 5 to pH 11 range. A compromise pH level may be set when more than one metal is targeted for removal at the same time and through only one process step. The removal efficiency of one or both metals may be affected by operating at a compromise rather than optimum pH level.The MetClean process generates non-hazardous solid waste. Waste can then be disposed of more easily than brine or sludge.CITATION:Christensen, T C, Vendrup, M and Dube, C, 2015. Pilot tests for heavy metals removal in mine water, in Proceedings MetPlant 2015, pp 404–415 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Gray N. B

The need to improve existing metallurgical processes and to develop new processes to meet the economic challenges that lie ahead requires the application of the tools of process analysis viz. mathematical models, physical models, pilot plants, laboratory measurements and plant tests. Examples of the application of these techniques to processes are described in this paper. Several of these techniques, combined with basic knowledge, are necessary to make improvements and for existing processes this always involves plant measurements. Also because metallurgical processes include extraction, refining, alloying, casting, mechanical working and heat treatment, an interdisciplinary approach to research and development is essential. This paper argues that metallurgical engineering is a discipline that is uniquely able to encompass the broad spectrum of chemical- and physical-metallurgy processes and is therefore essential to the health of the metallurgical industry.Regrettably many metallurgical engineering departments are not offering courses on process analysis, control, optimization, etc so necessary to meet modern industrial challenges.

Jan 1, 1985

By X Z. Sun, N Jiang, J H. Zhao, C X. Wang, L Y. Bai

In backfill grouting for underground coalmines, the filling materials strengthen the caving rock and support the overlying strata to reduce surface subsidence. The broken roof strata fail and collapse during mining operations without appropriate supporting measures being taken. It is difficult to perform continuous backfill mining on the working face of such roofs using the existing mining technology. Therefore, in order to solve the above problems, fly ash and mine water are considered as filling materials, and flow characteristics of fly-ash slurry are investigated through laboratory experiments and theoretical analyses. Laws governing the diffusion of fly-ash slurry in the void of caving rock masses and in the void between a caving rock mass and a basic roof are obtained and verified. Based on the results obtained from the above analyses and field conditions at the Zhaoguan coalmine, Shandong Province, China, a cave backfill grouting system of the hauling pipeline is developed and successfully tested at the 1703 working face. The results demonstrate that a filling rate of 43.46 per cent is achieved, and the surface subsidence coefficient of the grouting process is found to be 0.475. Compared to the total caving method, the proposed system is found to achieve a reduction rate of 40.63 per cent. This effectively helps in lowering the value of the surface subsidence coefficient. Fly ash and mine water, considered as primary materials in this study, also play a significant role in improving the air quality and water environment.

Nov 29, 2022

By G J. Corbett, T M. Leach

Although hosted within an Ordovician magmatic arc, the Peak Hill high sulphidation system displays features typical of youngerPacific Rim high sulphidation epithermal gold deposits. Regional NW trending transfer structures are inferred to localise the magmatic source at their intersection of the NS trending arc. Fluids have migrated from the magmatic source along NW structures and thence exploited permeable horizons, which have become silicified. Alteration displays typical zonation from silicification through assemblages characterised by alunite, pyrophyllite and kaolinite and is followed by breccia/fracture controlled sulphide and gold deposition. Sinistral rotation on the NS arc has dilated NW trending fractures to produce the WNW to EW dilational fractures which host the higher grade ore. Mineral assemblages are typical of formation distal to the magmatic source in an epithermal environment. The combination of alteration and mineralisation zonation with structure provide fluid vectors which target a magmatic source to the SE of Peak Hill.

Jan 1, 1995

By E Kasai, T Nakamura, E Shibata

In the present study, formation of PCDD/Fs from carbon particles like æsootÆ, so called de novo synthesis, was experimentally simulated using the powder mixture of graphite and metallic chloride. Composite states of graphite and chloride particles were varied by the preliminary treatment, ie high-energy ball milling for different time or heating at different temperatures. These samples were subjected to the measurement of the rates of weight loss mainly due to the oxidation of carbon, the formation of absorbent organic chlorides (AOX) and the formation of PCDD/Fs at 300¦C. The amount of PCDD/Fs formation increased by applying certain pretreatments. Further, linear relationships were obtained among the formation rates of PCDD/Fs and AOX and the weight loss of sample. These results will give useful information to investigate the mechanism of PCDD/Fs formation from unburned combustible carbon and hydrocarbon in thermal processes.

Jan 1, 2002

THE Great Fitzroy Mines Limited, comprising an area of 183 acres, and held under lease, are situated at Mt. Chalmers, within the Cawarral goldfield, 18 miles from the city of Rockhampton, Queensland, on the Rockhampton-Yeppoon railway.The nearest railway station i; Mt. Ohalmers, distant about half a mile from the mine, with which it is connected by a fairly good road. The outcrop of the ore-body consists almost entirely of ironstained quartzite, no sign of copper being visible. The outcrop and its immediate vicinity have been worked intermittently for gold during the past :fifty years, the ore being amenable to battery treatment.About twenty years ago a company was formed to prospect this outcrop, and work was commenced by driving an adit, but the results proved disappointing, and work ceased. Later a party of prospectors sunk a winze from the adit level, which has sincedeveloped into wh~t is now known as the North shaft. The property was afterwards prospected by Messrs. Oharley and Osborne, who continued sinking the winze, meeting with sulphides at a depth of about 120 ft.The Mt. Chalmers Copper Mining Company was formed to work the property, and smelting operations started on a small scale. These, however, met with ip.different success, and the property was again abandoned.

Jan 1, 1911

By R van Berkel

Regional synergies concern the capture, recovery and reuse of by-products, water and energy between industrial operations in close proximity. The Centre for Sustainable Resource Processing (CSRP) undertakes applied research to further advance regional synergies in the Kwinana Industrial Area in Western Australia in order to achieve greater efficiencies in water, energy and materials consumption and reduction in waste and emission generation. The Kwinana Industries Council (KIC) and its member organisations recognise water consumption and disposal as key environmental issues. Some 30 companies in Kwinana consume a total of more than 35 000 ML/yr of fresh water. Over the past years significant progress has been made towards the reduction of water consumption and improvements in effluent disposal. As part of the CSRP Kwinana Synergies Project, water balances for the ten major water consuming companies have been completed, including workshop sessions with company staff on water synergy opportunities. This work resulted in a set of synergy opportunities which are currently being pursued. In parallel to the Kwinana project, the CSRP has commissioned a supporting project that delivers a toolkit to guide a more targeted and less resource intensive way to identify feasible water synergy opportunities. One of these tools focuses specifically on water, and takes count of input and output water flows within a given industrial area to deliver listings of prioritised water synergy opportunities. This paper discusses the water mapping and workshop approach taken in Kwinana and its outcomes, which are to identify and evaluate water synergy opportunities. The results from the trial application of the developed Regional Eco-Efficiency Opportunity Assessment Toolkit are also presented.

Jan 1, 2006

By J Williamson, M Griessmann

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Watershed tungsten deposit is located in the Hodgkinson Province of north Queensland, Australia. The deposit is hosted by Siluro-Devonian flysch-type meta-sediments of the Hodgkinson Formation, which were subjected to four major deformation events. Mineralisation has occurred syn- to post-D4 and is related to the intrusion of S-type granitoids of the Permian Whypalla Supersuite.Watershed is located within a regional NW–SE-striking melange zone composed of brecciated and intermixed arenites and shales. The major NW–SE-striking Tullah fault zone is situated in close proximity to the east of the deposit.The Watershed deposit occurs within a tightly folded upright anticline with NW-plunging fold axis. The anticline contains a major package of coarse-grained to conglomeratic arenite, which harbours the Watershed mineralisation. Several alteration styles occur within the arenites, of which Fe-poor calc-silicate alteration dominated by clinozoisite/epidote is the most significant. Less widespread but locally important alteration styles comprise garnet-dominated calc-silicate alteration, albitisation and sericitisation. The arenites are enveloped by unmineralised carbonaceous shales and shale breccias.Tungsten mineralisation occurs solely as molybdenum-poor scheelite and can be found as three styles: disseminated mineralisation in calc-silicate altered arenites, vein-style mineralisation with quartz-albite-scheelite veins and minor but high-grade mineralisation in albitised felsic dykes.Contact metamorphic rocks and geophysical data indicate the proximity of an underlying granitic body. It is believed that this granitic body was the main driver of the hydrothermal system generating the Watershed deposit. An early mineralisation stage caused the selective calc-silicate alteration of the arenites, while a second stage caused the vein-style high-grade mineralisation. The folded shales enveloping the arenites worked as an effective barrier that kept the mineralising fluids in a confined rock volume.The scheelite mineralisation at Watershed is open to depth, with a granite-hosted porphyry or greisen-style mineralisation anticipated below the current resource.CITATION:Griessmann, M and Williamson, J, 2015. The calc-silicate-hosted Watershed tungsten deposit, far north Queensland, Australia , in Proceedings PACRIM 2015 Congress, pp 545–550 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The paper sets out the context for water and the challenges that have to be faced in the battle to alleviate global poverty. It acknowledges that the world has been blessed with abundant water but because of population and development pressures, and the projected changes in climate, avoiding serious water shortages in some places will be difficult. MiningÆs use of water is placed in context and the paper then considers the specific threats to the industry in terms of availability and price and the need to find mechanisms to deal with the issue of resource degradation caused by abandoned mines. Rio TintoÆs use of water is then set out and three examples are given of how different water challenges have been addressed. The paper goes on to consider each element of a water strategy designed to move Rio TintoÆs performance towards excellence. This strategy incorporates improved management procedures (policy, principles, standards and targets), performance enhancement (through use of the Rio Tinto Water diagnostic and technology changes) and working with others in the academic and NGO community who seek to address the same global issue.

Jan 1, 2003

By G Harbort

The use of geological data for optimisation of operating plants has become a significant part of the modern process mindset. The underlying principle is to convert spatial geological data into metallurgical information to drive production and mine planning, blast design, blending strategies and plant set-up. Increasingly the process designer is required to interface with geological and mining staff to propose the best investment strategy for a project’s benefit.The geometallurgical model development for the Zafranal copper-gold project commenced in March, 2010, several months after the start of a major drilling campaign by AQM Copper Inc. The initial evaluation stage required review of historical Teck RC data to determine areas of metallurgical interest within the project. As drilling transitioned from RC to diamond drilling, core that was considered representative of the resource was selected and subjected to MLA mineralogy analysis. When coupled with sequential copper analyses this allowed calibration of an assay derived mineralogy model, allowing process concept options and a preliminary test program to be developed. This Phase 1 test program provided a preliminary process design, operating costs and anticipated concentrate grades and recoveries. Both this data and resource estimation were used to generate a preliminary Whittle pit optimisation based on maximising net smelter return, which in turn fed into a preliminary mine plan. The preliminary mine plan, in conjunction with geological logs and core results was used to develop a phase 2 metallurgical test program, where variability tests were conducted throughout the resource and composites formed to investigate specific years of the mine plan in locked cycle flotation. In addition comminution tests were modelled against geometallurgical domains allowing comminution components values to be calculated for 36?000 m of core. A flotation geometallurgical model was developed and incorporated into the resource model allowing concentrate grades and recoveries to be estimated on a block-by-block basis.

Sep 5, 2011

By T W. C Stambolie

Coalmines, like any other mine, generally involve the classic three-staged approach to mining studies; namely concept, pre-feasibility study (PFS) and feasibility studies (Cusworth, 2012). Subsequent to these studies, and in instances parallel to these studies, the commitment to an environmental impact statement (EIS) is made in order to secure both state and federal development consent. In recent times, the sentiment to both mining and coal is changing whereby the traditional approaches to mine planning and economic evaluation is complicated by evolving environmental legislation, expectations and time frames. It is all too common to take shortcuts in the development of projects in order to create the perception of cost savings and expediting the delivery timeline. Atkins (2016) points out that: boards of so many small to mid-tier mining companies, and a few majors, focus on relentless project delivery too early in the project process, with so little time and effort applied to risk analysis and option development. Unforeseen risks can cost any timeline or budget far more than the effort required assessing and mitigating these. The ultimate risk to any feasible coal project is that of environmental approval and achieving development consent.CITATION:Stambolie, T W C, 2016. A black canvas – planning a greenfield coalmine in New South Wales, in Proceedings Life-of-Mine 2016 Conference , pp 31–35 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

The kinetic and practical aspects of the extraction of copper from copper-rich solutions by cementation on iron was investigated. Tests were made on the effect of stirring speed, cupric sulphate concentration, acid concentration, temperature, and ferric sulphate concentration on the reaction rate and excess iron consumption.Most kinetic investigations were conducted under a nitrogen atmosphere to prevent any oxidation of the iron or copper metals. The stirring mechanism for all tests incorporated the use of a rotating impeller above a static disc in the solution. The activation energy for cementation on the steel disc at high stirring speed was 8·6 kcal/mole, indicating a predominant chemical control.Increasing the pH first decreased, then above pH 3, increased the reaction rate. Additions of sodium sulphate also significantly increased the reaction rate.The use of high temperature and high pH under an inert atmosphere has been suggested for increasing the reaction rate and producing a high purity sponge copper product.

Jan 1, 1972