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By G Fergus, M Hart, S W. Weeks

Rio Tinto Alcan has undertaken feasibility level assessments into the expansion of its bauxite mining operation in an area south of the Embley River in far north Queensland. The project has the potential to extend their Weipa operations by approximately 40 years.The construction and operation of two additional mineral ore processing plants are proposed for the South of Embley project. Golder Associates was engaged to develop and conduct modelling assessments of potential sources of water supply required by mineral ore processing.Two models were developed using GoldSim: a dam yield model and a water balance model. GoldSim is a graphical object-oriented modelling environment with a capacity to carry out dynamic probabilistic simulations. Originally developed by Golder, GoldSim has been applied successfully in a decision support role to a range of mine water management operations.The dam yield model was used to provide estimates of reliability and volume of annual water supply of several potential surface water dams. This information was then used to determine a hierarchy of water supply options for processing plant operations. The water balance model dynamically simulated the water demands of the two production plants and the consequential response in water supply, with respect to the timing and discharges provided by the various source options.Use of the model provided a preliminary operational tool to assist with water supply management decisions. Water quality issues required a blending of water from separate sources and attention paid to scheduling to ensure water supply through the dry season. The model also helped identify risks to water supply in the event of underperformance of one or more water supply sources. This allowed the operational rules to be refined to minimise those risks.The dynamic and stochastic modelling approach provided a method for identification of water supply issues susceptible to seasonal climate variability.CITATION:Weeks, S W, Hart, M and Fergus, G, 2013. A dynamic evaluation of water supply security susceptible to climate seasonality, in Proceedings Water in Mining 2013, pp 197-208 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By K Ellis, B Lumsden

A full-scale statistically-based on/off plant trial of a new flotation conditioning technology designed to improve fine mineral recovery was undertaken to determine whether the recovery of selected fine sulfide minerals can be increased. The technology is selective for certain sulfide minerals only, including chalcopyrite and sphalerite. The technology has been shown to selectively aggregate the fine chalcopyrite and sphalerite minerals giving increased flotation recovery. The plant trials have shown an increase in the mineral recovery, without decreasing selectivity. Size by size recovery shows a significant increase in the fine (

Jan 1, 2005

This paper explores the use of a Process Safety Management (PSM) system to manage risk in the mineral processing and metallurgical refining industries. Important elements of a PSM system are described. International regulations and non-regulatory guidelines covering PSM for high hazard industries are reviewed. Case studies of incidents in the mineral processing and metallurgical refining industries are presented to understand the lessons learned from failure to manage risks using a PSM system. Conclusions are drawn to adopt PSM in the minerals and metals processing industry as a tool for loss prevention and risk management.

Jan 1, 2003

By M Hernan

Bendigo Mining Limited has established a modern underground gold mine and processing plant at Bendigo in central Victoria. The Bendigo goldfield produced around 22 000 000 oz of gold between 1851 and 1954. Approximately 4 000 000 oz were sourced from surface alluvial workings with the remaining 18 000 000 oz won from underground quartz reefs. The modern mine is accessed via the Swan Decline, which commences at the Kangaroo Flat site on the southern outskirts of Bendigo and progresses in a north easterly direction between the Deborah and Sheepshead anticlines, reaching a depth of almost 1000 m below the City of Bendigo. Development of this decline commenced in 1998. Since that time 20 km of underground development has been completed. Exploration drilling, on-reef development and bulk sampling carried out between 1999 and 2005 resulted in the estimation of a Probable Ore Reserve of 700 000 tonnes at 9.0 g/t gold for 207 000 oz of gold. These Ore Reserves were contained within four reefs located on the Deborah and Sheepshead anticlines. Reef mining commenced in late 2005 from the Shywolup and Greater Garrard reefs. Material mined was stockpiled on the surface in preparation for commissioning of the process plant which commenced in mid 2006. Mining and processing were carried out between August 2006 and May 2007 during which time 176 000 tonnes were processed at an average grade of 5.4 g/t gold to produce 26 735 oz of gold. Plant feed was sourced from four reefs. This paper discusses some of the issues which were encountered with the definition and mining of these geologically variable and nuggetty reefs. This paper covers exploration techniques, grade estimation, mine geological control, mining methods, geotechnical issues and reconciliations. It will also discuss some of the lessons learnt and how these will be applied to future Mineral Resource and Ore Reserve estimation, as well as underground operations.

Jan 1, 2008

By I Lumsdaine

QNI Pty Ltd operates the Yabulu Refinery located 25 kilometres north of Townsville, North Queensland. The plant treats nickel laterite ores sourced from the Philippines, Indonesia and New Caledonia. The cobalt head grade and overall recovery expectations for the 2001/2002 financial year are 0.161 per cent and 53.8 per cent respectively. Cobalt is a valuable byproduct derived from the nickel refining operation which utilises the Caron Process. Any increases in cobalt recovery that are achieved from the existing relatively low level provide significant improvements to the bottom line of the operation. Towards the end of 2000, a project was undertaken to characterise cobalt losses with the sole purpose of improving cobalt recoveries using a variety of analysis techniques. The Time-of- Flight Secondary Ion Mass Spectrometry (TOF-SIMS û University of South Australia) method was used to verify the presence of surface bearing cobalt species, originating from either co-precipitation or adsorption mechanisms. Cross-section examinations were also performed using Scanning Electron Micrscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDXS). These techniques indicated the presence of high cobalt concentrations (in the order of several per cent) within a select number of roasted and leached ore particles. The phenomenon of cobalt losses due to incomplete leaching within specific ore particles was not widely documented within the Refinery prior to these studies. In order to quantify losses via this mechanism, Mineral Liberation Analysis (MLA û JKTech Centre) was also performed on key samples. This paper serves to document a systematic approach in determining the source of significant valuable mineral losses in an established, operating plant. It discusses the use of a variety of analytical techniques, which have been adapted for the minerals processing industry, but are strongly relevant for plant investigations in the hydrometallurgical industry.

Jan 1, 2002

The nation of Fiji is located the South Pacific on the æRim of FireÆ some four hours flying time from the eastern sea board of Australia. It is a tourist destination situated on the main route from Australia to the Americas. Fiji is a developing country that has had a fewsetbacks but the country has able, happy people that are very resilient. Most importantly, the country is a safe destination for tourists and businesspeople as the local people are friendly, have good ethics, and most speak English. Fiji is a very willing nation, hungry for knowledge and advancement. The Fiji geological setting on the æRim of FireÆ, that runs from New Zealand across the Pacific through Fiji and on to Papua NewGuinea, has many large deposits of gold and copper. Fiji is an exciting destination for mineral explorers with discoveries of gold, silver, manganese, bauxite, iron and copper. Gold was first discovered in 1921 and the first two mines opened in 1935; one of which was Emperor Gold Mining Company (EGM) the other being Mt Kasi. EGM mines gold on the margin of the Tavua caldera, some 85 km north of the Nadi international airport. EGM has operated continuously for close to 70 years, producing approximately 6.9 million ounces of gold and has an underground reserve of 847 600 ounces with a total mineral resource of 12 335 600 tonnes at 10 g/t (as given in the Emperor Mines Limited Annual report 2003). The mineralisation in Fiji is very exciting and it is common to discover spectacular intersections and outcrops, which are typical for this type of epithermal narrow vein mineralisation, but be aware that the orebodies are variable and not easy to understand.

Jan 1, 2004

Among countries afflicted with insLantaneous outbursts of coal and gas, Australia is noteworthy because of lesser disturbances of the seams and of the occurrence of CO2 in the seam gas from place to place. Research sLarted with the 1954 occurrences at Collinsville and Metropolitan Collieries leading to early publications reviewing the problem, describing occurrences and assessing variations in proneness factors in the two affected coal basins.The basic requirements for proneness include coals of high gas sorptive capacity, high ground stress, use of a mining method which provides higher stress concentrations and limits emission of seam gas, including high rates of advance. With CO2 in the seam gas proneness is greater.The mechanism is complex and not fully understood, but involves the coal, the roof, the floor, the gas, the mine opening, the ventilation, the kind of work and the rate of work. Geological disturbances such as faults and dykes increase proneness and tend to localise occurrences. On-occurrence of outbursts in some mines is difficult to explain.Outbursts are seen as a continuing threat to modem deep Australian mining of high rank coal.The simplest contributory factor to reduce is gassiness - despite the low permeability of outbursting coals - and present practices are showing promise. The greatest challenges for the future are partial degasification to below a known threshold figure and confirmation that this reduction is achieved and identification of anomalous geological structures ahead, the most likely locations for instantaneous outbursts to occur. The advances made to date give promise of a future with reducing experiences of uncontrolled instantaneous outbursts. For the Bulli seam particularly, working to achieve prediction and prevention is most urgent.

Jan 1, 1993

By Prakash AJ, Singh PK, Dhar BB

Safety and stability of underground mine openings, coal pillars and water dams in the near vicinity of operating surface mines are endangered from excessive blast induced vibrations. This paper deals with the investigations carried out in four coal mines. Simultaneous measurements at equal distances from the source indicated higher level of vibration on the surface than those produced in the underground workings. The values of peak particle velocity (PPV) measured on coal pillars, body of water dam were lower than those measured on roof and junctions of the roadways. The parting of coal (3-4.5 m) between two sections vibrated with higher PPV compared to the roof of top section and floor of bottom section. In one case the influence of total charge fired in a round was significant in generation of vibration compared to the maximum charge/delay where monitoring was done vertically below the source.

Jan 1, 1995

By Lee H. G, Li H, Hayes P

Slag from the smelting of lead can contain up to 20 per cent zinc as an oxide. An understanding of the lead smelting process and of the subsequent fuming process for the recovery of zinc is enhanced by a knowledge of the activity coefficient behaviour of zinc oxide in smelting slags. The literature presents a wide range of contradictory values. This paper critically reviews the published data and outlines new measurements being made by the authors. A consistent set of zinc oxide activity coefficient data is presented for liquid slags within the ZnO-'FeO'-CaO-A1203-SiO2 system, through a combination of present and previous measurements.

Jan 1, 1993

By J D. Pease, J M. I Tuppurainen, P D. Munro

This paper examines how legislation and regulation can be external drivers of technical change in mineral processing and extractive metallurgy and how the industry can respond. Two examples are considered; the production of copper metal from concentrates and the cyanide process for gold production.The Clean Air Act (1970) in the USA initiated a wave of attempted innovations in the extractive metallurgy of processing copper sulfide concentrates to meet forthcoming standards on sulfur dioxide emissions. Interestingly, a satisfactory technical solution existed (flash smelting and gas capture) but had not been widely adopted.Nearly fifty years later the primary copper industry finds itself with new challenges. One major challenge is how to deal with the increasing level of arsenic in copper concentrates. Most countries impose an upper limit on arsenic in imported concentrate; typically, 0.5% As or less. Higher arsenic concentrates can be blended with cleaner ones to meet the limit, but this tactic cannot be used indefinitely as the average arsenic level of global concentrates rises inexorably. Further, smelters (often in urban locations) cannot be expected to deal with both ever-increasing arsenic in the feed and stricter restrictions on emissions and disposal. A rising “inventory” of primary copper deposits are already constrained from development by high arsenic concentrate. These deposits will need to be developed if future copper demand is to be met. An economic and technical solution to arsenic is needed. The gold industry may also face challenges in the use of cyanide, by far the dominant lixiviant used in gold and silver production. Public perception has driven restrictions on the use or transport of cyanide in some jurisdictions. History suggests that such pressure is only likely to increase. While there are several alternative lixiviants, none can yet match the utility and economics of cyanide.Such important issues will not be resolved by incremental change or new equipment items. They require development of new process technology - a tectonic event rather than an incremental change. It requires sustained effort (and expenditure) over decades and is very unlikely to result from “business as usual” for producers, suppliers or academics. Past major process developments were driven by a dire need for economic survival or by legislative change. What will drive the future changes?CITATION:Munro, P D, Pease, J D and Tuppurainen, J M I, 2017. Technology change by regulation – a cresting wave?, in Proceedings MetPlant 2017, pp 45–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Jarvensivu M, Ylinen R, Jamsa-Jounela S-L

The paper presents a new integrated system for control of concentration processes. The system is based on cluster-based modelling taking the ore quality into account and a new on-line particle size analyser capable also for reliable measuring of particle size distribution of concentrate. A metallurgical precontrol audit was performed at the Hitura concentrator in order to design the control strategy of the integrated grinding and flotation control. A new analyser PSI-200, was used to the measurement and control of the distribution of nickel in the total particle size range. An expert control system using the cluster model together with a new control strategy for decision of necessary control actions is outlined. The method has been tested to real data from mineral processes. The results are in good correspondence with empirical process knowledge. KEYWORDS: Cluster analysis, expert control, flotation control, mineral processes, modelling, particle size.

Jan 1, 1993

Traditionally, the development of a mineral resource project goes through a fairly set pattern of decisions from what commodities to search for; where to look; how to locate; what are the reserves; how can they be exploited with optimum returns for all stakeholders; where are the markets and what will be the price received; what financing arrangments? However, due to the unique nature of most mineral resource properties, the relative significance of individual parameters on the ultimate development decision will vary from project to project. Sensitivity analysis in its formal sense is most frequently related to the economic analysis of a project particularly in conjunction with the ultimate development decision making process, and acknowledges the uncertainty of the actual values with their impact on the corporate decision making yardsticks. In many cases, this analysis merely adds more values to confuse the decision makers who may well opt for some subjective rationale to overcome the numeric confusion. However, sensitivity analysis should be used more frequently to exploit the development dollar to its maximum, THROUGHOUT the phases leading to the development decision. It is essential to identify the critical inputs to the various decision tiers in a project as early as possible and direct the funds to ensure that these parameters are determined as accurately as possible. Examples are used to illustrate the need for an even-handed quantification of the parameters which affect the outcome of decisions en route to the final one while minimising the risk in making an optimum assessment in relation to development funds Available.

Jan 1, 1983

The pilot scale testing of Australian coals for their NO, emissions was carried out at the ACTC to investigate the influence of coal properties, furnace conditions and different NO,, control strategies on NO,, emissions. The NOx emissions for the Australian coals tested were found to vary over a wide range and primarily depended on combustion temperature and excess oxygen conditions. These coals did not exhibit any fundamental difference in NOx levels to other world coals. Under similar combustion conditions, the conversion of coal nitrogen to NO. was found to be best correlated with coal rank parameter, R, max per centage. The use of staged combustion as a control strategy was shown to reduce their NOx levels by 56 - 77 per cent.

Jan 1, 1991

By D Mcleod, S Brindley, S Green

The design and engineering of flotation circuits is driven by numerous inputs, including (in no particular order) testwork outcomes, site considerations, type of separation required, energy sensitivity of the flotation response, personal experience and preference for flotation machines, maintenance access requirements, operability, level of automation and capital constraints.This paper discusses these and other issues in the Australian context and covers the flotation of copper/gold ores and polymetallic (copper/lead/zinc) ores. The paper discusses aspects of the following: how should testwork be done and what are the important inputs and outcomes? how should testwork results be interpreted and how does this impact on equipment selection? what processes can have a critical impact on flotation circuit performance, eg thickening and regrind? what options are available with the typical æflatÆ Australia site? how do you minimise capital cost and what impact can this have on flotation circuit operation and maintenance? how should circuits be controlled and operated? Particular focus is placed on some practical aspects of process design and engineering and the potential impact that engineering decisions can have on flotation plant operation.

Jan 1, 2005

By J T. Sharp, M A. Styler, D McGowan, P W. Mayne

Static liquefaction is a geotechnical hazard in mine tailings facilities. Soils that are contractive in shear are susceptible to static liquefaction. Tailings facilities are dynamic structures, typically growing in height each year. Dilative tailings may become contractive under increased effective stress. In this paper we show that Cone Penetration Test (CPT) data can be used to estimate the future state of in-place tailings under changes in effective stress. Susceptibility to static liquefaction is typically evaluated with the CPT by using a clean-sand equivalent normalized cone tip resistance (Qtn,cs) or by estimating the state parameter (?). An alternative approach is to evaluate the soil-state using the yield-stress-ratio (YSR = ?’y/?’v0). If the YSR equals one it is on the normal consolidation line and the soil-state is contractive. YSR values greater than three are typically dense of the critical state line (CSL) and the soil-state is dilative. In this paper we review how to calculate Qtn,cs, ?, and ?’y; and how the YSR can be used to screen for contractive soil behaviour. Unlike Qtn,cs and ?, it is very simple to estimate how the YSR will change due to an increase in overburden stress. This YSR approach was evaluated at three locations that saw increases in overburden of 10 m, 20 m, and 25 m. We show that the ?’y calculations are consistent and the increase in effective stress moves the soil state towards looser soil states. CITATION:Styler, M A, Mayne, P W, McGowan, D and Sharp, J T, 2018. Predicting changes in static liquefaction susceptibility using cone penetration test results, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 317–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The Peko copper orebody is associated with a body of magnetite rock which it has partly replaced. The primary ore averages about 9 per cent. copper and 4 dwt. gold per ton and locally IS much richer. It consists essentially of chalcopyrite and unreplaced magnetite, with lesser amounts of pyrite, marcasite, pyrrhotite, cobaltite, bismuthinite, native bismuth and native gold. The earliest formed mineral is wolfram, and the latest formed is goethite, so that the temperature of deposition ranged from about 5000 C. to 1650 C. or lower.Oxidation extends to 270 ft., which is 100 ft. below the present water level. The oxidized ore consists of cuprite and native copper, and has replaced more or less massive chalcocite of a former zone of secondary sulphide enrichment. The present zone of secondary sulphide enrichment extends from about 270 ft. to 310 ft. depth.INTRODUCTIONThe Peko mine is about 6 miles south-west of Tennant Creek township in the Northern Territory, adjacent to a small outcrop of hematite rock that projects above an otherwise featureless "bull-dust" fiat.The copper-gold orebody being developed in this mine did not outcrop. It was first detected in 1950 by a surface diamond-drill hole (DDH.1), which intersected primary copper ore at a depth of 400 to 425 ft. This ore contained from 4 to 11 per cent. copper and 1 to 25 dwt. gold per ton. Since then a shaft has been sunk, and crosscuts and development drives have been opened on the 210..ft., 300-ft. and 400-ft. levels, which are also connected by winzes. Two diamond drill holes sunk from the 400-ft. level have intersected theorebody at about 450 to 460 ft., and a winze from the 400-ft. level intersected the lode from 445 to 500 ft. At this point it is 54 ft. wide, and averages 9 per cent. copper. More recently an inclined surface drill hole (Peko No. 1) has cut the lode at 856 ft. to 921 ft., equivalent to a vertical depth...

Jan 1, 1955

Control of construction projects is the responsibility of the Project Leaders who have the authority to make decisions. Project Controls cost and scheduling systems provide the Leaders with timely information on which to base their decisions.The Client (Owner) will invest up to three per cent of the project cost on Project Controls. To ensure that this investment is effective, the Owner or Manager must have a clear understanding of the information required from the Project controls systems. If appointing a single Managing Contractor, the Owner or Manager must stipulate what is and what is not required from the Project Controls Systems. There are numerous computer programs available for scheduling and cost control and it is important to select systems which best serve the Owner's needs.

Jan 1, 1993

By G F. Johansen

The erratic and localised occurrence of economic gold grades is a common feature of high-nugget effect gold veins. The nugget effect is a consequence of small-scale geologically controlled enrichment, and the inclusion or exclusion of sparse gold particles because of the sampling process. Such deposits do not always contain visible or coarse gold, and can be characterised by fine gold particles. Economic grade accumulations are generally contained within discrete oreshoots, which are surrounded by barren to low-grade material. Problems are often encountered where small sample types (eg drill core or channel samples) often vastly understate in situ grade, due to their general inability to intersect rare gold particles. As a result, the definition of grade and its distribution is often challenging, and leads to substantial resource uncertainty. Proxies, or indicators for grade, can help the geologist gain a better understanding of grade distribution and grade potential. These are based upon geological (eg mineralogical, textural, etc) and/or geochemical (eg specific elemental ratios, fluid inclusion compositions, elemental correlations, etc) criteria. The paper discusses the use and application of such proxies through three case studies.

Jan 1, 2004

To enable ammonium nitrate-fuel oil (AN-FO) to be used on an equal weight basis with nitroglycerine explosives, smaller diameter bore holes became necessary with consequent modifications to drill steel and burden on holes. Detonation of AN-FO in small diameter holes proved successful both with and without primer charges but some alterations were required to adapt anoloders to the smaller holes.Important factors in training all operators in the new charging method were the retention of improved fragmentation, avoidance of excessive overbreak and keeping wall rock dilution to an absolute minimum. The successful storage of ammonium nitrate in climatic conditions with daily temperature fluctuations above and below the critical 90°F has been achieved.INTRODUCTIONTechnical aspects of ammonium nitrate-fuel oil (AN-Fa) blasting agent are well covered in recent literature. This paper deals primarily with the manner of its introduction as the principal explosive underground at Great Boulder Gold Mines Ltd. and with the many problems encountered in the process. Following reasonably successful experimental firings in June 1962', using granular ammonium nitrate and an anoloder, permission was granted by theWestern Australian Mines Department to carry out test work in selected areas of the mine. The permit allowed for fuse firing only, and for a mixture of AN-Fa containing between 5t and 6 per cent fuel oil, with an adequate primer.The use of AN-Fa on an equal weight basis with nitroglycerine explosives, involved smaller diameter holes with alteration to ground burden and modification to drill steel.Initial tests indicated that it was apparent that AN-Fa could not replace gelignite on an equal weight basis if the...

Jan 1, 1965