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By Anderson J. M, Gillies A. D S, Jones N

There are a number of current theories in relation to methane migration and emission into workings following underground coal mining activity and some controversies do exist. Mining causes changes in the stress regimes in surrounding strata and results in fracturing. Permeability increases and methane flows into workings under a pressure gradient. The effects of stress on permeability depend on the physical properties of the coal and surrounding strata. Methane emission also depends on the original methane content and the proportion which will be liberated. There are several methods for determining in situ methane content and desorption characteristics of coal samples and several methane prediction methods but clearly more research is necessary to achieve an adequate predictive model.

Jan 1, 1992

In the mid-1990s, after a long period of antipathy between the company and its detractors, Rio Tinto embarked upon an ambitious cultural change program that sought to transform the fundamental basis of its relationship with global, national and local stakeholders. This has evolved into a broader pursuit of positive cultural change within Rio Tinto as part of the mining industryÆs Sustainable Development initiative. Initially driven from the top down, the communities component of this program comprises an architecture of policies, value statements, social research and verification systems. The commitment to better community relationships is best exemplified in Australia by the scope and scale of the GroupÆs Aboriginal land access agreements, community development programs and the work of the Rio Tinto Aboriginal Foundation. While collectively these form the core elements of an evolving set of internal social competencies, development of second-tier competencies is required to organically embed a culture of sustainable relationships with local and regional communities. Second-tier competencies will include appreciation of social dynamics, social science and diversity at middle management level; rigorous social research that properly informs development options for companies and host communities; career paths and recognition within the mining industry for young professionals both generally and from stakeholder communities; proper community-needs assessments, research into such things as purchasing power and other economics data, and inventories of public goods such as land-carrying capacity and water availability. Without this information it is difficult to gain an appreciation of and to alert people to the consequences of change brought on by a mine. The next decade will see second-tier social competencies promoted within successful mining companies. Measures to achieve this include a range of Human Resource (HR) incentives such as recruitment and career advancement based on broad competencies rather than narrow technical proficiency, humanities training for mining professionals and performance rewards that recognise social competence. A sustainable future for mining in a globally connected social landscape requires selection of people who can listen, relate and act in an open social system. The challenge for the mining industry, its professional organisations and educational institutions is to acknowledge this and develop these new aspects of mining industry professionalism. This cannot be left to individual companies if the industry is to have a sustainable future.

Jan 1, 2002

By Piotto P

Pit optimisation algorithms are designed to produce a pit with maximum value, but for certain minerals like iron ore, limestone, coal, etc, it is also necessary that the designed pit contains ore which meets the customer's chemical specifications. This paper describes a technique of using linear programming for blending optimisation and the Lerchs-Grossmann algorithm (as in Whittle's 3D software) for pit optimisation in tandem, to achieve pit designs of targeted grade specifications.

Jan 1, 1996

By Burchell S, McGregor K

The process of design, measurement and review is essential if blasting is to continuously improve to meet the increasing productivity goals of most mining operations. To achieve continual improvements, many operators are turning to contractors to provide the necessary technology. Under this arrangement, the contractor becomes the supplier of a service rather than products and assumes some of the risks associated with blasting by guaranteeing the end result. If contractors are to obtain significant productivity improvements they must continuously improve every aspect of their business.

Jan 1, 1994

Subsidence data resulting from longwall mining in the northern part of the Newcastle Coalfield of New South Wales has been reviewed. Themain factors influencing subsidence variability in this area (apart from width/height ratio) are strong bridging strata, the effects of the first major goaf fall, mining direction and depth of cover. In 1987 the NSW Department of Mineral Resources produced a guide to subsidence prediction for the Newcastle Coalfield which is still widely used. The current study shows this guide to be no longer appropriate for this area. An alternative prediction curve, incorporating more recent data, is suggested.

Jan 1, 1998

By T Perera, B Fan, S Thang, T Hsia

Minerals are valuable resources and critical elements for a broad range of biological and technological applications, including technological developments to improve energy efficiency and the global movement to promote a low-carbon economy. However, in order to extract these critical metals, large amounts of waste and toxic chemicals are generated, as well as the use of high energy and large amounts of water consumption. Froth flotation is one of the most commonly used processes to separate and collect high-value minerals, but it still has some limitations, including low flotation efficiency performances using existing collectors and other reagents. Therefore, there is an urgent need to design and develop new metal-specific collectors to more efficiently separate and recover valuable minerals and to allow bulk water recovery from flocculated tailings. In this research, we propose to use our newly designed and synthesised novel collectors derived from a type of vitamin E (α-tocopherol), a relatively inexpensive and non-toxic natural molecule. As a potential collector-building block, α-tocopherol has a long hydrophobic carbon chain that facilitates the attachment to air bubbles during the froth flotation process. In addition, the phenol group of this molecule can be easily modified to incorporate various functional groups for targeting different types of minerals. Furthermore, α-tocopherol can be converted into a monomer for polymerisation by the reversible addition-fragmentation chain-transfer (RAFT) process, which can provide us with polymer based-collectors with high precision control of molecular weight and architecture. So far, small-scale qualitative experiments on α-tocopherol-based collectors have been performed with good results, which indicates the feasibility of these compounds as novel collectors for improved froth flotation processes.

Aug 24, 2022

This paper provides an overview of current and future mine developments in the major island nations Indonesia, Papua New Guinea (PNG), New Zealand, and Fiji, and the French territory of New Caledonia. Many of the other 11 small island nations in the region, such as Vanuatu, Pulau and the Solomons have been the subject of considerable exploration orientated towards gold in the past few years but without any deposit found with confirmed economic viability.

Jan 1, 1990

By Hryniewicz M

The paper presents a sound critical estimate of mathematical models presently used for the process of compaction of fine-grained materials. It shows the mathematical model of compaction developed by the authors, which was used to formulate the program of computer simulation of the process. The examples of computer simulation experiments of compaction of selected fine-grained materials regard the results of the experiments made by the authors on variability of external friction occuring in this process. Simulation examination presented in the paper crucially contributed towards the original method of selection of rational compaction technologies of fine-grained materials developed by the authors.

Jan 1, 1993

By Kwok S, Haemmerle A

Treatment methods for a low grade deposit at Mt. Fitch near Rum Jungle, N.T., were investigated. Physical beneficiation of the ore, sulphuric acid leaching, carbonate leaching and various methods of uranium extraction from the leach liquor were studied. Although the deposit occurs in a carbonate environment, acid leaching of the ore after beneficiation by radiometric sorting appears to be the most economic treatment method. Uranium would be recovered from the leach liquor by solvent extraction.

Jan 1, 1970

By Wang Y. J

This paper describes a more generalised or generic approach for the mine ventilation network problem. More specifically, it defines the network variables in a manner that establishes the network problem in a nonlinear programming format. Assigned to each branch are three variables: air quantity, regulator pressure loss and fan pressure. Each variable is imposed with lower and upper bounds. Based on these, the generalised network problem for a mine ventilation network with B branches is presented as a system of B independent network equations in 3B unknowns (variables) with variable bound restrictions, and it is classified as a nonlinear optimisation. A nonlinear programming model has been developed for this generalised network optimisation problem. The model is formulated and transformed into a standard equality-constrained nonlinear programming form with given variable bounds. Then, MINaS (Modular In-core for Nonlinear Optimisation System) is used to obtain solutions. Examples are given to illustrate this nonlinear programming approach to the mine ventilation optimisation problem.

Jan 1, 1993

By S R. Grano, J Duan, T A, D Fornasiero

We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.

Jan 1, 2005

By Bell MG

At various decision points in the development of a project, a developer, joint venture partner or financial institution may require an independent review of the basic assumptions and technical aspects of the project. This type of review or technical audit is becoming a more common feature of the project development process. This feature has evolved because of the need of investors and lenders to be more confident of the viability of a project by the confirmation of its technical and cost aspects. Technical Audits offset some uncertainties introduced by the combination of longer development periods for, projects and the highly dynamic world economic scene. This paper reviews the place, nature and process of the technical audit by examining the circumstances when it might be needed, the typical scope of work or brief, the responsibilities of and relationship between the auditor and the client, and the auditing procedure. Detailed aspects of technical audits are discussed followed by a case study of the Hail Creek Coal Project Audit.

Jan 1, 1983

By A Crawford, P Manton

Telfer is a gold/copper operation, currently operating one open pit mine and one underground mine. The ore processing plant consists of two parallel trains involving semi-autogenous mill, ball mill and crusher (SABC) grinding, flotation and leaching. Due to receiving relatively high grade underground ore for over half of its total feed, Train 1 frequently experienced cleaning circuit overloading during high production periods. This resulted in losses in recovery and ineffective concentrate upgrade. As a quick and simple solution, the Train 1 copper flotation circuit was reconfigured to send concentrate from the first two rougher cells directly to the final concentrate and return the cleaner scavenger tailings to the third rougher cell. These modifications have resulted in a 1.4 per cent increase in plant copper recovery with no change in final concentrate grade. Preliminary results also indicate gold recovery has increased by more than 1 per cent since the circuit reconfiguration. Other benefits include less spillage, more friendly circuit to operate and a more consistent metallurgical performance. Focus for the next phase of optimisation is on concentrate upgrade. A number of opportunities have been identified and are currently being investigated, including staged reagent addition, single stage cleaning of the first two copper rougher concentrates, regrinding of the remaining copper rougher concentrate prior to cleaning and process control based on a machine vision system.

Jan 1, 2009

The earliest caveman, very much a minority group, in the face of great adversity and person- al peril, had to take his livelihood by stealth or force of arms - aided by some degree of reas- on and ingenuity. He was pretty much a law unto himself. As time went on, his type became more numerous; and, after bumping heads with the- tough bloke who lived in the cave across the valley, he decided that perhaps he ought to try to get along with him. Perhaps he could trade some over-ripe emu meat for that `roo skin that he had tried to take. Then too, next time he wants a woman, he had better use a lighter club and just stun her a little - that last one was pretty badly bashed. Perhaps he should keep her around the cave and train her to keep the fire going, gather some roots, and skin the game. Those joeys of hers are kind of cute too. Of course they eat, and it would necessitate bringing in more food. So man gained increasing responsib- ilities to his family and neighbours. He domesticated animals, learned that he could cultivate certain plants that were palat- able and would supplement the meat diet, and found that he could modify earth materials to make tools - he became a grazier, a farmer, a miner and a manufacturer. He ceased to be nom- adic and community life came into being. This complicated life and made more rules essential.

Jan 1, 1974

The purposes of defining the mining environment for underground mass mining and the uses of characterisation data are outlined. The requirements for data in the areas of geology, surface and groundwater hydrology, topography and environmental constraints and geotechnical studies are identified. Emphasis is then placed on the collection and interpretation of geotechnical data for establishing the in situ stress regime and for rock mass characterisation. Methods used for diamond drilling, core logging, borehole logging, data analysis and presentation, rock mass modelling and rock mass classification are outlined. Finally, recent and potential advances in the state-of-the-art are identified in areas such as geophysical methods, measurement while drilling, computerised data collection and analysis, rock mass modelling, in situ stress measurement data presentation and interpretation, and some applications of rock mass characterisation data.

Jan 1, 2000

By Nyamekye GA, Subramanian S

Adsorption tests have been carried out to elucidate the interaction mechanism between dextrin and sulphide minerals. Sulphides such as galena and heazlewoodite exhibit high affinity adsorption over the pH range that coincides with the iep of lead and nickel hydroxides, and is suggestive of chemical interaction. The adsorption behaviour with respect to the sulphides of copper is of the low affinity type, and follows a different pattern. The adsorption studies on graphite, support the chemical interaction mechanism, with the metallic impurities serving as adsorption centres. In conformity with the proposed mechanism selective separation of galena from chalcopyrite and heazlewoodite from chalcocite has been Achieved.

Jan 1, 1993

Prefeasibility planning and cost estimation of conveyor systems has historically been undertaken by comparing fi xed plant transport requirements to that of similar systems in service. This paper describes the development of a prefeasibility conveyor technical design and cost estimation application using Microsoft Excel Visual Basic for Applications (VBA) platform. The application tool known as D-Convey (Dachshund Convey) was developed with the goal enabling the end user: to develop a technical model for conceptualised conveyor systems, to perform economic analysis on the developed technical model, and to conduct a comparative and risk analysis. An Excel VBA based platform was utilised to draw upon both the analytical and graphical capabilities of a spreadsheet. Some of the features of D-Convey system include a revolutionary dynamic graphical help system, known as the 'information pane' in lieu of traditional help fi les as well as the use of familiar graphical user interface elements such as the MS Offi ce 2007 task ribbon. The D-Convey system incorporates material database allowing for mass handling prefeasibility estimation in other industries; it has been validated at a local quarry.

Dec 6, 2010

By Fitter JF

Drilling and blasting practices at Groote Eylandt are undergoing a period of rapid change. Practices over the last ten years are reviewed and some specific blasting problems currently being faced are described. A move from percussion to rotary drilling is outlined, together with the reasoning behind a proposed return to ANFO from watergel explosives. A brief outline of the various firing patterns used is given, together with a description of the drilling and blasting recording procedures currently in use. Current and planned developments in drilling and blasting at Groote Eylandt are also outlined, emphasizing the success of wide patterns, fired in line with long inter-row delays.

Jan 1, 1982

By Seeley D, Buckley N, Goodall J

Improving the performance and reducing the costs associated with export logistics chains is critical to the competitiveness of export coal mines. The fundamental practices associated with the use of export logistics chains made up of mine, trucking, rail and port operations are being challenged by the advent of third party operators on rail systems and the use of the Internet.Whilst individual mines can improve their processes to drive down their mining costs, they face major challenges in their endeavour to improve the performance of export logistics chains and reduce the significant logistics costs of moving coal from the mine to export ships, via the shared infrastructure of rail systems and ports. There is an increasing realisation that global competition is not only between mines but between coal export regions that are defined by their rail system and ports infrastructure.

Jan 1, 1998

The Merrill-Crowe process for gold and silver recovery yields a low grade concentrate containing high levels of zinc and copper. External refining charges and high transport costs prompted the company to establish itsown enrichment facility.The route chosen was a wet chemicaltreatment which converts the gold, silver and other metals to their chloride. This is achieved with hydrochloric acid and sodium hypochlorite. Gold is recovered from the resulting filtrate by cementation with copper.The solid residue from the gold process is washed and treated with ammonia which dissolves the silver chloride. Metallic silver is recovered from this solution, againby cementation with copper.

Jan 1, 1985