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By M Akbarpour, M Osanloo

In mining industries, materials handling costs represent a significant component of the operational cost. A variety of methods have been applied in surface mine equipment selection in order to select the suitable loading system with the lowest loading operation cost. These are queuing theory, bunching theory, linear programming and genetic algorithm. Among them, genetic algorithm is a simple method and applied for preliminary selection of the loading system. In this study, gathering information from anomaly No 2 of Gol-e-Gohar iron mine of Iran, loading system (number and its capacity) has been optimised by genetic algorithm. The study results showed that two shovels 8.25 m3 are required for the removal of 60 million tonnes of overburden. After removal overburden, these two shovels contribute to the extraction of 42 million tonnes of ore with a stripping ratio of 1:1.

Jan 1, 2007

This paper provides an insight into the current status of risk management practices within our industry, based on an industry wide survey, with deliberate cross-reference to quantitative analysis. This survey showed that quantitative assessments appear to be mainly hampered only by the lack of reliable data and industry expertise to carry out such assessments. A short case study will illustrate some of the necessary basic tools and data types that would enable the industry to tap into an additional range of business improvement dimensions to more effectively manage the diverse and changing risk profile of the mining sector.

Jan 1, 2003

The mining industry worldwide relies upon the identification of resources that can be economically developed and operated. Access to land is paramount through all stages of the exploration, development, operation and rehabilitation stages. Clear rights to use of land for the purposes of mining must be available and protected throughout the life of the project. Stable and enduring criteria for mining of the resource, once identified, are required to attract exploration and development expenditure. The purpose of this paper is to investigate the varying approaches to granting access to land for use for exploration and mining development, including the processes by which a project is approved by community and government and the time scale for such approval. The paper concentrates on the legal issues arising throughout this process. The law is stated as at September 1997.

Jan 1, 1997

Wrenching between basement blocks is considered to be the mechanism whereby a well developed set of en echelon folds and an associated fracture system are developed in the Fitzroy Depression, Western Australia. The regular geometry of these structures accords with a right lateral regional coupling between high-standing, basement blocks bounding a trough filled with a thick pile of stratified Phanerozoic sediments. The structures developed during or after the Mesozoic Era, but the couple is inferred to have been applied to blocks outlined by old lineaments, which may reflect strains or ruptures in basement that developed during the Precambrian, and which were regenerated during Palaeozoic and Mesozoic time.

Jan 1, 1967

Over the past 5 years, Bougainville Copper Limited has undertaken a number of major plant expansions to the copper concen- trate production plant at Bougainville in the North Solomons Province of Papua New Guinea. These projects have scheduled three additional ball mills, three new banks of Outokumpu flotation cells, four additional tertiary screens, two additional tertiary crushers, and more recently four high capacity 24.5m dia. tailing thickeners. The value of the five separate projects totalled more than A$100 million. A requirement of commissioning and bringing on line of each of these projects has been to minimise both operational losses and copper concentrate production. The commissioning has been successfully implemented by detailed planning of the commissioning work in conjunction with the plant operation. Planning has been detailed for each man involved on an hourly basis, highlighting the work required on each commissioning task that is to be undertaken and the time expected to achieve activity Completion.

Jan 1, 1986

Process control computers are finding ever increasing applications within the chemi-cal and mineral processing industries.To purchase a system which fulfils both the immediate and future needs of operating, technical and management groups, requires an appreciation of the capabilities of the system software and the constraints which apply to user development of application software. Early decisions are then required as to who will develop and maintain the software. Rules and conventions must be determined and adhered to if the end result is to be an orderly, well structured and properly documented system. Software development and maintenance represents a substantial, and often hidden, cost. Getting it right the first time will avoid either a major re-work, or having to live with a system which is extremely diffi-cult (at the worst, impossible) to trouble-shoot or modify.

Jan 1, 1985

Independent assessments of existing and projected mining operations are often required in the exchange of assets and for raising capital, requirements which are particularly prevalent where there are new mining fields, a characteristic of the Pacific Rim area. Such audits and appraisals typically consist of a geological evaluation of the ore deposits; estimates of mineral inventories and mineable reserves; assessment of mine plans and costs; assessment of ore processing methods, recoveries, and costs; assessment of infrastructure and G&A (general and administrative) requirements and costs; assessment of environmental, permitting and reclamation requirements and costs; and, finally, economic evaluation based on various discount rates and metal prices. Audits provide a challenging task for consulting engineering companies, but one well worth the effort for mine developers and those connected with financing of the mining industry.

Jan 1, 1990

By W F. Bawden, J T. Paynter

This investigation involves laboratory testing and stability analysis of paste fill at the Golden Giant Mine. Site-cast samples are tested in unconfined, confined, and consolidated-undrained triaxial compression. Pore pressures during shear and consolidation characteristics are measured to determine both drained and undrained shear strength parameters and assess the potential for undrained loading. Liquefaction potential is also considered. A limit equilibrium solution is used to obtain factors of safety against failure of the fill during mining of adjacent stopes.

Jan 1, 1998

Soil improvement technologies have been widely employed over the recent decades to overcome tunnelling problems in difficult grounds, their range of application growing proportionally to the technological development. The constant advancement in the different mechanical (flexible and more powerful equipment) and electronic (enhanced reliability and direct quality control) aspects of these technologies, fostered the confidence of engineers and tunnellers and, ultimately, allowed the entire tunnel industry to approach difficult excavations in a safer and cost effective manner.This paper outlines the main features of commercially available soil improvement techniques, with particular emphasis on permeation grouting and jet grouting. These two technologies, developed concurrently in Europe and Japan, and there customarily adopted in the design of underground structures, have known extensive and extreme applications worldwide in recent years. Case histories and current practice of soil improvement techniques, as they apply to tunnelling, are also rendered.

Jan 1, 1999

By Massy-Greene RB

Limited recourse financing techniques reduce the financial exposure of equity holders to major mining projects by transfering some of the risks to the banks which provide loan funds for project development. This can only be achieved by a clear understanding of the principles involved. Engineering and management decisions on how the resource is to be developed and extracted must be made in the light of lender's requirements. The structure of sales contracts, joint venture agreements and many other documents can be important in limited recourse financing. If projections show that the debt can be repaid from project cash flow, loan agreements and other arrangements can restrict lenders ability to look to the equity holders for repayment of project loans.

Jan 1, 1981

Over the past decade most, if not all participants in the resources sector have been involved in initiatives to improve margins, reduce costs and improve business profitability. In many cases the initiatives undertaken have fallen short of their stated objectives, and in some cases have resulted in the terminal decline of the underlying business. In reviewing why many such initiatives fail, a common theme of arbitrary cost reduction and a focus on minimising cost as opposed to maximising value and cashflow emerges. This paper proposes a structured process that allows mine owners and managers to develop an understanding of their cost structure and optimise production and cost outcomes from the business. The broad objective of cost optimisation is to create value by getting more out of existing and new assets by focussing on operational areas, particularly production and maintenance. The paper uses practical examples to highlight the application of cost driver trees as a mine improvement tool.

Jan 1, 2002

The paper reviews winder rope inspection procedures at the Non Destructive Testing (NDT) Unit of Western Australian School of Mines (WASM) and outlines measures taken to adopt the world's best practice. The measures include acquisition of a new type of rope tester, adoption of comprehensive rope rejection criteria, adoption of a standard rope inspection procedure and formal training of the wire rope inspectors.

Jan 1, 1995

By J J. Cilliers

The aim of this paper is to give an overview of the FrothSim flotation simulator and to demonstrate its ability to predict the performance of real flotation circuits. Example simulations are presented in which the feed rate to the circuit is varied, followed by simulations in which a cleaner section and recycle loop are added to the rougher bank.The simulator is able to predict both the recovery and the grade produced by the cells at all locations in a circuit and the simulator is shown to produce plausible grade recovery curves. It also demonstrated that the performance of banks of cells improve as the feed rate to the bank increased (improved grade for a given recovery), but that more cells are required to give the same overall recovery.

Jan 1, 2005

By Gibbons S. L, Ritchie I. M, Murr D. M

Fundamental studies on the transformations of iron oxides have been carried out and related to the solution conditions in the Becher process. The results show that a number of iron oxide interconversion reactions occur in the aeration reactor with the products depending on the pH, temperature and oxidation potential of the aeration liquor. It is concluded that the lack of process control in the aeration reactor of the Becher process significantly hinders the ability to predict and produce high quality single phase iron oxides of a consistent colour.

Jan 1, 1990

Peko Mines N.L. has considerable experience in the treatment of a wide range of comparatively small orebodies.Gold-silver, bismuth, and sulphide and oxide copper ores are treated under difficult geographical conditions.Treatment of these ores is complicated by some unusual metallurgical factors.Metallurgical operations are described, including the treatment of the gold-bismuth-copper ore from Juno. The new Warrego mine is to have a highly instrumented concentrator by December 1971. Autogenous grinding is being considered.

Jan 1, 1969

By Goode RA

It is-assumed that a pipeline system is economically justified as a means of transportation.. The terms "True Life" and "Economic Design Life" are defined. The most usual design alternatives to be considered from both physical and economic -viewpoints are listed and a summary is given of the main factors to be costed in assessing the relative economics of each alternative. A brief statement of the recor mended method af economic. assessment is given and an example is included. The paper aims to present a reasonably accurate, simple and practical method of considering the main economic factors which govern design.

Jan 1, 1962

Dragline performance drops considerably when chop-down and double handling of material is needed due to increasing overburden thick- ness or total pit depth. Beyond a certain pit depth the dragline needs support by a pre- stripping system in the upper portion of the overburden. In soft to medium hard ground the bucket wheel excavator can be used for pre- stripping, whereby several methods of material transport are investigated. Conveyor transport around the pit and dumping by stackers is the best solution from the technical point of view. Cross pit transport and dumping by means of a conveying bridge is the method with the lowest costs per volume moved. Cross pit transport by use of a beltwagon with overlong discharge boom is both, poor from the technical point of view and high in overall costs.

Jan 1, 1981

The attachment of a spherical particle to a bubble is theoretically investigated under the condition of a mixed sorption coating of a collector. It is shown that the attachment is determined primarily by the hydrodynamic factor involving the displacement of liquid from the gap between a bubble and a particle. The dependence of the attachment on the state of the surface of particle (sorption coating) is due to a change in the boundary conditions on the interface with water both in the case of surfactant chemical sorption and in that of the physical adsorption of oil. It is demonstrated that at large distances the thinning of a interlayer is facilitated by a physically sorbed collector, while near the bubble this is done by a chemically sorbed one.

Jan 1, 1993

It is self evident that in many cases mining disrupts communities, however, community reaction to mining varies enormously. This is due to a whole host of factors, some physical, some financial, some political and some a direct result of the projected mining company attitude towards the community at large. Physical and political factors are increasingly being dealt with realistically and financial aspects are to a significant extent determined by profit margins. If the acceptable profit margin canÆt accommodate all necessary costs (which now includes a variety of community considerations unheard of even a decade ago), then the project is just not viable. Despite major commitments now made by many mining companies to their affected communities, corporate attitudes, and their projection, remain as the most outstanding factor in mining project development where real gains can still be made in effectively reducing social risk. This paper addresses both international and domestic experience gained in managing this aspect of mining development risk, including initiatives implemented by multilateral institutions.

Jan 1, 2003

By Berglin IK

Since 1962, ferro alloy production in Australia has been concentrated at Bell Bay, Tasmania with a major expansion occurring in 1976. This concentration was based originally on the perceived requirements of the expanding Australian steel industry, but recent stagnation within this industry has seen Temco become progressively more export oriented.In 1984, approval was given for a $47 million uprating of facilities which will allow for the introduction of the latest technology to ensure high quality, low cost production in a highly competitive export market.

Jan 1, 1985