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By S Jahanshahi, T Norgate

In single stage copper making appreciable amounts of copper report to the slag phase. Various strategies are available to minimise copper losses to the slag. However a slag treatment stage is likely to be required in an economically viable process. A number of slag treatment process options are available and include: flotation, leaching and thermal reduction. In the design of an industrial process some type of economic as well as technical analysis of these options will be required. In this paper an outline of the techno-economic analysis procedure used to design a single stage copper making process is presented. The calculated operating and capital costs of industrial copper making processes are compared and used to determine the optimum single stage copper making flowsheet. The most economic slag treatment options is flotation of slags containing low amounts of copper.

Jan 1, 2000

Over the last 15 years the contract mining concept has developed into an integral part of the Australian mining industry. Today it is a $2 billion per annum industry with the potential to continue to grow at a rate of between ten and 20 per cent. Australian contract miners have also exported the concept overseas where growth prospects are unlimited. The industry today is at a cross-road where both contractors and mine owners must consider the current state of the contract mining industry and where it is heading. To look at the present and the future, it is necessary to look back at the history of contract mining and why it has developed. Current industry concerns can then be summarised and the areas that need to be considered to enable the industry to prosper, reviewed. The ultimate goal is to reach solutions with benefits to both the mining companies and the contractors.

Jan 1, 1996

By S A. Johnson, J Cassidy, J L. Mauk

Geophysical anomalies at Puhipuhi reflect both diverse lithologies and different degrees of hydrothermal alteration. Most significant is a strong negative gravity anomaly (up to 50 g.u.), encompassing but extending beyond areas of known alteration, which is modelled as a deep zone (up to 3 km) of reduced density in the host greywacke basement. This zone, interpreted as being due to alteration (at least in part), closely correlates with the extent of overlying basalt flows. The gravity data indicate that the most intense alteration occurs below the basalts and correlates with the location of previously inferred hydrothermal upflow zones. These observations suggest that the basalt may have acted as a cap rock to a mineralising geothermal system. Aeromagnetic data identify highly variable but typically low magnetisations in the basalts which suggests that alteration may have been contemporaneous with volcanism. These geophysical data at Puhipuhi confirm the locations of centres of known alteration and suggest potential exploration targets below the basalt cap where there is no surface manifestation of alteration. Further implications of these results are discussed in Locke et al. (1999).

Jan 1, 1999

The correct assessment and understanding of geotechnical conditions is fundamental to mine design and, hence, successful (safe and efficient) mine planning, design and operations. However, this assessment and understanding is simply not possible unless there is a sound appreciation of the geology of the project. This paper addresses geological uncertainty in mine engineering and its communication, and shows that a mining project that does not take geology properly into account in the engineering phase is fraught. Uncertainty levels become excessive, which leads to hazards and consequential risks in design and operations in terms of both safety and efficiency. Several examples, both positive and negative, are provided to make the point. The paper concludes that mining geologists must become more overtly cognisant of the influence of geology on mine engineering. Equally importantly, mining (and geotechnical) engineers must communicate better with their geological colleagues to ensure that they (the engineers) have a clear understating of the geological issues affecting their operations. The engineers must know how to ask the right questions of the geologists. Engineers who do not understand and take account of geology in their designs and operations are failing the expectations of stakeholders.

Jan 1, 2006

As this Seminar is on "Progress - Mining and the Environment", I am taking the liberty of extending my address beyond the scope implied by the subject, "Rehabilitation of Mined Land", with a preliminary discussion on broader economic issues relevant to "Progress and Mining in Western Australia" before discussing its effect on the Environments Western Australia is nearly one million square miles in area and has a population density of approzimately one person per square mile. Because of its vastness it has wider climatic variations than any other Australian State. The north is tropical and the south is in the temperate zone. The major portion of the State is an arid plateau with less than 10 inches of mean annual rainfall. The climate, rainfall and soil conditions of the South-West region are more favourable to agriculture than any other part of the State and consequently was settled first. The immediate need of the colonists being food and shelter, the early economy was based on farming and forest products.

Jan 1, 1971

The T33-34 blast, the first major blast at Mount Isa Mines, broke 1,360,000 tonnes of copper ore using 349 tonnes of explosives. The original concept of firing T33, T34, T35 and U37 separately was changed during the life of the project due to adverse ground conditions. These conditions also caused the stoping method to be modified after the firing of the stopes had started. To stabilise the two stopes T33 and T34 where large fall off was occurring, rib pillars were left in the original slot. This caused the blast design to be more complex as these rib pillars had to "lead" the blast. The implication of such a large blast on the underground and surface environment was thoroughly investigated and precautions taken. The charging time of the blast was six weeks. Hook-up was started four days before the blast and continued until two hours prior to the blast. Detailed scheduling was carried out of other work that had to be done in the 24 hours before the blast to ensure that there were no delays in the firing.

Jan 1, 1977

By Morley I. W

Offshore minerals legislation has been introduced to provide jurisdiction over the exploration and recovery of mineral resources, particularly petroleum, from the territorial waters and parts of the continental shelves adjacent to coastal states. Ratificat- ion of the 1958 Geneva Conventions on the Law of the Sea has provided some measure of international agreement amongst signatory powers. Because the relationship of the Australian States to the Commonwealth in their federal system, the Australian offshore petroleum legislation is of particular interest. The customary role of the States in mineral resources management, which has extended to the offshore, is under challenge from recent unilateral Commonwealth Government legislative actions in the fields of mineral resources jurisdiction. Environmental considerations provide an additional issue, as yet unresolved, with the delay in submission of the Report of the Great Barrier Reef Petroleum Drilling Royal Commissions

Jan 1, 1974

By M A. Mular, T Akroyd

A fundamental model, which considers the subprocesses of particle collection by bubbles in flotation, is applied to two comprehensive flotation surveys in the rougher stages of C3 concentrator, PT Freeport Indonesia. The flotation surveys focused on the collection of: cell-by-cell and size-by-size metallurgical, cell hydrodynamic, and pulp and surface chemistry information.The two surveys were conducted at significantly different feed tonnages, giving rise to significantly different feed particle size distributions, pulp densities and mean pulp residence times. A series of model simulations are performed with the aim of quantifying changes in copper recovery, on both a size-by-size and unsized basis, with changes in values of the hydrodynamic parameters and hydrophobicity of the copper sulfide mineral. This was carried out in an effort to identify the most promising route to increase overall copper recovery in roughing. It was found that by increasing the hydrophobicity of the copper sulfide mineral surfaces it became possible to optimise cell hydrodynamics, which targeted increased fine (-12 ¦m) copper sulfide mineral recovery but without adversely affecting coarse (+150 ¦m) copper sulfide mineral recovery.

Jan 1, 2007

One of the more recent developments within the mining industry has been the adoption of formal continuous improvement programs. A continuous improvement (CI) program was launched across Kalgoorlie Consolidated Gold Mines (KCGM) in early-2002. The purpose of this program was to identify further operating improvements within departments. The focus of the continuous improvement program was not only on the areas of the operation which were performing below expectations but also on areas of the operation which were performing well but could still be further improved.The effectiveness of a continuous improvement program depends on the stability of the processes in place and the participation of many employees from all levels of the business.Continuous improvement has had some successes and failures at KCGM and this paper will discuss both within the open pits department. Further improvements that could be made to the process will also be discussed. Kalgoorlie Consolidated Gold Mines Fimiston operation is located in the Kalgoorlie Goldfields and it the largest gold mine in Australia producing over 800 000 ounces of gold per annum.

Jan 1, 2004

In this paper is given a general description of the Black Star copper orebody, its relation to the lead orebodies and the controlling factors in the mineralisation.Copper ore, in the form of chalcopyrite, was first noted at Mount Isa in 1930 during the surface drilling campaign to prove the downward continuation of the silver-Iead-zinc orebodies.Details of the occurrence are set out in table 1.Other sub-commercial widths were also disclosed and examination of these occurrences showed that commercial mineralisation could not be expected within 800 ft. of the surface. It was therefore decided that further exploration was not warranted until underground workings had advanced to this horizon.Detailed surface mapping showed two small outcrops of the host rock of the copper orebody. One occurrence, 50 ft. x 75 ft., was of quartz, with leaching suggesting former dolomite. Another outcrop, further north and west of silicified shale, with low grade oxidised copper, has recently been found. Both occurrences were above the hangingwall of the main copper orebody.When the workings in the silver-Iead-zinc orebody reached No. 7 level (875 ft. below the surface) further...

Jan 1, 1953

By J Sarvinis

The design and operational aspects of fluidised solids transfer-cooling devices will be discussed in this presentation. The devices include air slides and fluoseals (also called seal pots, loop seals, etc), which are widely used in metallurgical plants and other processing plants. Cooling can be achieved while solids are transported in the solids transfer devices. The units combining solids transfer and cooling provide compact and clean plant layouts and also reduce capital and operational costs. Fluidised devices provide excellent gas-to-solids and gas/solids-to-surface heat transfer rates, hence high cooling efficiency. Fluidising gas, such as air, nitrogen or other gases, can be used as direct cooling mediums. Coolants such as water, steam and other liquid or gas cooling fluids can be used as indirect cooling mediums via tube coils immersed in the fluidised solids. The fluidised transport devices share some common features with fluidised bed equipment. The air slide is similar to a linear fluidised bed while the fluoseal is similar to a circular fluidised bed. Therefore fluidised bed design techniques are applicable to the design of the air slides and fluoseals. The heat and mass balance and temperature profiles of the devices concerned will be discussed in the presentation. The design criteria and operational philosophies of the critical components such as tuyeres and air spargers will also be discussed.

Jan 1, 2006

By Pollard D. M

The removal of nickel from lead by sulfur drossing was investigated using a technique which models industrial batch decoppering practice. Successful denickeling to 0.005% (Ni)pb was consistently obtained in the absence of silver, well below the experimental equilibrium value of 0.015% but still above levels obtained in industrial practice. Silver appeared to have little effect upon denickeling. The final nickel content was dependent upon the initial nickel content, the total sulfur addition and the stirring time. The presence of nickel was found to give no assistance to successful decoppering. Simul- taneous removal of nickel and copper was observed at silver contents in excess of 0.02%. Extended stirring resulted in a further lowering of the nickel content but reversion of copper to the bullion was observed. Experimental work has shown that nickel can be removed by a standard decoppering operation; a procedure which is used in secondary lead re- fining. Alternatively nickel can be removed during initial decoppering in primary lead re- fining operations.

Jan 1, 1987

By S Totsuka, P Ortiz, E Prokkola

Electrochemical polarisation techniques can be successively applied to maintain clean surfaces in process environments. The applications are the result of extensive knowledge of the electrochemical nature of process environments, an innovative approach to problem solving and shared æcan doÆ attitudes between the supplier and process owner. Initial identification of suitable applications is based on over 20 years of process and electrochemical experience. The technologies discussed in this paper include Electrochemical Anti-Scaling [EAS], Electrochemical Protection Systems with both anodic [EPSA] and cathodic [EPSC] protection and Electrochemical Flocculation [EF]. Examples of industrial applications are reviewed. Good examples of metallurgical processes which can benefit greatly from an advanced electrochemical treatment are the wet processes involving precipitation, crystallisation and evaporation. Eliminating corrosion and scaling which would otherwise cause process disruptions and quality problems can make a big difference in process profitability. Clear advantages in both cost efficiency and environment friendliness are easily demonstrated. Continuous processing with minimum downtime is one clear advantage. In comparison to the use of corrosion inhibitors, anti-scaling agents and flocculants, the electrochemical polarisation does not increase the environmental load from the process as no additives of any kind are used. In most cases the cost benefits from pro-actively keeping surfaces clean with the help of advanced electrochemistry are substantial when compared to traditional re-active methods and other active treatments.

Jan 1, 2004

By T Raynlyn, J J. Campbell, J M. Young

In order to correctly predict the performance of beneficiation processes, such as hydrocycloning or ultrasonic treatment of iron ore fines, it is important to understand possible changes in size distribution, mineral composition and textural peculiarities. During beneficiation processes, iron ore can be subjected to various physical actions which may result in changes in size distribution. In the case of soft or friable ores, attritioning and/or deagglomeration may have a significant effect on both separation performance and product stream specifications. Optical image analysis tools, which give statistical information on a particle by particle basis, can help in better understanding the response of the ores to these processes. An experimental study has been conducted to investigate the response of a haematitic-goethitic iron ore to a combination of stirring and ultrasonic treatment. The effect of stirring and ultrasonic treatment on the size and mineral distribution has been quantified using image analysis and automatic ore texture classification. This approach has been applied to several size coarse fractions of the initial feed and product. The results show that, following treatment, the mass proportion of ore texture classes which contained higher amounts of ochreous goethite and kaolinite had significantly decreased compared with that in the feed, while the proportion of texture classes where haematite was the major mineral had increased. Liberation analysis also showed a significant increase in the proportion of particles with more than 95 per cent haematite and vitreous goethite.

Jan 1, 2007

Obvious differences in mineral deposit types occurring in Outer Melanesia and Northern Chile can be related to the sub- marine-dominated nature of volcanism in the' former area and the subaerial-dominated nature in the latter area. Subtle variations in subvolcanic epithermal-porphyry ore systems between the two areas probably result from differing ore fluid compositions. Hydrother- mal convection cells in Outer Melanesia will be seawater-dominated, consequently rela- tively high salinities and chlorine contents will characterise the ore solutions. Trans- portation of metals as chloride complexes is likely and the ease of seawater sulphate reduction to sulphide in the ore systems will lead to widespread, sparse dissemination of sulphide minerals. Relatively low grade por- phyry copper deposits will typify these ore systems. In Northern Chile hydrothermal convection cells will usually be dominated by meteoric waters. Consequently ore fluid salinities are likely to be lower and chlorine will be less abundant. Under these circum- stances transport of ore metals as bisulphide complexes could be important. Boiling and loss of H2S gas from these fluids would lead to rapid precipitation of metals and higher grade deposits. Erosion rate is a very important factor in the preservation of ore deposits and this may be the major control on the richness of a metallogenic province. The abundance of mineral deposits in the El Salvador region of Northern Chile compared to Fiji is probably a function of the much lower rates of erosion in the former area.

Jan 1, 1987

By M Delaney

Alliancing is a contractual relationship in which organisations with an interest in a project are brought together in an atmosphere of co-operation to produce superior results to benefit all of the participants. Fundamental to the concept is the management of the risks associated with the project. The traditional risk management strategy adopted by clients has been to transfer this risk to others in the belief that this will result in the lowest overall project cost. It is assumed that competition in the market place will allow these risks to be transferred without paying a premium. However, this approach often results in the development of an adversarial climate, a high level of litigation, time and cost overruns and an overall poor project outcome. Under an alliancing arrangement the parties (client, designer and contractor) are aligned through shared interests in the projectÆs success by linking profitability to performance. Under such an arrangement, an atmosphere is created whereby the participants are motivated to focus on cost-savings, pursue best value and to innovate. Successful alliancing can result in highly motivated project teams and realisation of extraordinary productivity and cost-savings flowing from increased efficiencies. The situations in which alliancing can be successful are discussed with particular reference to the Wandoo Alliance which successfully completed the $375 million Wandoo B offshore oil platform in record time and with considerable savings to the project budget.

Jan 1, 2000

Three transient phenomena have been observed and experienced in the operation of large solvent extraction mixer-settlers. These relate to the ability of the settler to discharge streams with low entrainments arising from different phase separation æproblemsÆ. The operation of large-scale laboratory and commercial solvent extraction settlers has been shown by a number of workers to be a dynamic process, especially at the feed end. Circulating flow patterns are common in all three organic, aqueous and emulsion phases. The circulating patterns in deep dispersion bands in long settlers are believed to form roll fronts that can travel down the settler length within the bounds of the dispersion band. Various physical models are proposed to illustrate the formation and movement of roll fronts within the dispersion band. Another transient phenomenon has been observed in commercial settlers operating without any dispersion band. Entrainment of the continuous phase in the advancing dispersed phase is at high and erratic levels. This supports the conventional separation model, which recommends the presence of a significant depth of dispersion band to æfilterÆ the secondary haze from the bulk separated phases. The third transient is the position and shape of the dispersion band within the settler. Large commercial settlers have been shown to exhibit high variability in both these aspects of the dispersion band. The elimination of all three transient phenomena in commercial settlers has been shown to be effective with an in-settler media of coarse size and moderate specific surface area. The effect of the media is two-fold: it dissipates both the circulating flows and the forward velocity of any roll fronts, and creates a stable deep dispersion band at the feed end that serves to trap secondary haze from the primary coalescence process. It is effective in treating both types of transients involving non-existent or excessive dispersion band depths. The media serves to enhance coalescence by providing a static surface of intermediate surface tension on which droplets can collapse. The random nature of the media also provides multiple stream splitting and re-combination, that presents further drop to drop and drop to media impingement, which in turn promotes coalescence.

Jan 1, 2000

Geotechnical practice combines the site engineering geological model with engineering design and operations to control risk. The responsibility of the geotechnical professional is to present relevant engineering geological information to an engineer to effectively impact an outcome. Return is enhanced by understanding expected operating and capital cost due to ground conditions.   Risk is effectively communicated by a successful geotechnical practitioner. In a mining environment the need is to assess ground conditions accurately and quickly, and to effectively communicate expected ground response due to mining. A good engineering geological model includes a description of geotechnical engineering parameters to design assuming reasonable expected soil, rock and water conditions. Pit slopes are steepened, stope spans widened and waste foundations and land forms are constructed all under geotechnical control.   The responsibility of the geotechnical professional is to collect, assess and disseminate relative engineering geological information. The geotechnical professional is a person advising on ground related engineering, and generally operates within geology and engineering end members.   Return is better assessed on an understanding of ground cost. In operations the goal is to meet production at lower cost. In evaluation, regional and exploration geology, mine design and expected operational factors influence expected cost and project return. Return allows companies to meet shareholder expectations, attract equity to develop and add value to the community.   This paper presents a discussion with some examples to present an approach and design philosophy for geotechnical practice in the mining industry.

Jan 1, 2004

Water is a key resource input to copper heap leach operations in both quality and quantity. A number of recent developments in analysis of the technology have shown that water consumption can be optimised. The leach consumption has been generally considered in terms of minimisation of the evaporative loss by changing the application method (drippers or wobblers). Modelling of the irrigation effects on leach rate has shown that the poorer surface coverage from drippers has an adverse effect on the leach extraction rate. This is particularly evident in the early part of the leach. The use of different irrigation systems during alternate parts of the leach cycle can have benefits in minimising the water consumption without an unacceptable outcome from extended extraction times. By combining the leach rate effect with the evaporative loss estimates, an economic decision matrix can be generated to allow the operator to select an appropriate leach irrigation strategy, combining both irrigation delivery and irrigation rate. In the SX-EW plant, the total quantity of EW bleed and SX scrub stage bleed (both for iron control) can be reduced to an absolute minimum. The economic minimum may be different depending on the cost of producing the high-quality water used to replace the bleed streams. Adjustment of the SX process, in particular use of multiple entrainment control steps, can provide significant reductions in the total bleed and make up requirements.

Jan 1, 2003

By R Willis, D Cooke, G J. Davidson

Mine-groundwater interaction at the Pasminco Rosebery Mine (PRM), western Tasmania, deserves special attention due to the unique climate and mining environment present. High rainfall and low evapotranspiration result in an excess of water, an uncommon problem at Australian sulfide bearing mines. Research is being undertaken to delineate current subsurface fluid flows and predict future fluid flows in order to improve management after mine closure. Acid mine drainage generation is well developed in abandoned mines throughout the area. If acid mine drainage is not controlled after mine closure, significant environmental degradation could occur in the receiving waters of the Pieman River system. The study area encompasses the heavily forested Mount Black, and underlying PRM workings. Groundwater flows beneath Mount Black through a crystalline fractured rock aquifer with faults and underground mine workings observed to act as the major hydraulic conduits. Recharge is controlled by local precipitation, and the ultimate discharge is thought to be the Pieman River system, which forms the topographic low in the area. Slug tests have been used in conjunction with the mineÆs extensive geotechnical database to spatially evaluate variation in hydraulic conductivity. In fractured rock terrain associated with mining, rock quality designation data can be a useful tool in delineating areas of similar hydraulic conductivity when combined with conventional hydrogeological methods. A GIS, mine planning software, an environmental and a geological database are linked to form the input for groundwater modelling.

Jan 1, 2003