Search Documents

By Jiricek F

Legislative change has reformed the licensing process in Victoria. The Mineral Resources Development Act 1990 and the two stage system of licensing with the authority to commence work is discussed. A key part is the requirements of planning consent, being either an Environmental Effects Statement or the issue of a Planning Permit prior to the issue of an authority to commence work for mineral extraction. Examples of recent experience is discussed.

Jan 1, 1997

By Anderson DR, Tassell G

A major environmental impact study carried out in the sand dunes of eastern Cape York used image analysis of remotely sensed data to both select sites for ground investigation and categorise the different ecological units present. The approach adopted was particularly suited to the type of environment in question and allowed a high degree of quantification, at a high level of confidence, at costs several orders of magnitude less than conventional Methods.

Jan 1, 1987

Since the days of Adam Smith and Milton Friedman the discussion of corporate citizenship and sustainability has been flooded with multiple contradictions, with proponents of sustainability saying that it is a crucial cog in the business strategy, while those against, maintain that æthe business of business is businessÆ and therefore sustainability issues are just add-ons. Sustainability arises from a deeply held vision by corporate leaders that businesses can and should play a role beyond just making money. Businesses should embrace the understanding that everything that a company does has an impact both internally and externally (communities, employees and customers), and the natural environment. This paper highlights the approach that led to a view that there is a contradiction between profitability, sustainability and community development, and we provide a further argument to the contrary. This argument is based on a comprehensive literature review of over three decades by various scholars linking corporate social performance and corporate financial performance. Driefontein Gold MineÆs approach is that of linking the community development, natural environmental and employee well-being initiatives and projects to the mineÆs business strategy. The paper further highlights the coordination and implementation mechanism of sustainability at the mine where the accountability lies with the head of the mine operations. A two pronged approach is employed where there is an internal dialogue on sustainability between the various departments coordinated by the sustainable development department and an external tri-sector partnership with local government, interested and affected parties and the mine. These approaches are closely linked to the contributions towards the mineÆs financial bottom line.

Jan 1, 2009

The transportable moisture limit of a mineral concentrate (TML) is of great importance in the shipping of that material from Australian ports. Each year Australian mining companies incur substantial costs as a consequence of delaying shipments and/or multi-handling concentrates so as to comply with transportable moisture limits. Despite this there is a general lack of in-depth knowledge concerning factors that influence the parameter. Eight major Australian mining companies supplied sizing, specific gravity and TML data for their concentrates. Zinc, lead, copper and bulk concentrates were represented in their data. Estimated surface areas of the concentrates, as calculated from their normalised sizing data, correlated strongly with the reported transportable moisture limits. This high correlation prevailed in spite of the acknowledged limitations associated with the use of multi-sourced data and the adoption of simplistic approaches in the normalisation of sizing data and the estimation of surface area. Based on the broad range of concentrates studied, concentrate sizing data were concluded to offer potential as an alternative means of reliably estimating transportable moisture limits.

Jan 1, 1993

By G Solly, P J. Leevers

Day-to-day operating practices at existing operations need provide high quality data for decisions that will impact directly on the potential value of the available resource, in addition to meeting standards of quality expected of data used in feasibility studies that will be completed to obtain additional capital required to finance operational improvements. Drill hole location, down hole survey and assay data standards of accuracy and precision have received considerable attention in recent years. The authors propose that geological descriptions of both cored and non-cored drilling warrant at least equal attention, considering their fundamental role in establishing the framework used for geological modeling and resource estimation. The iron ore deposits of the Middleback Ranges have been a major source of iron ore for almost a century. High-grade hematite-dominant ore is currently mined by OneSteel from three open pit operations supplying ore to the companyÆs integrated steelworks at Whyalla. A review of OneSteelÆs future iron ore resources, commenced in 2002, highlighted the need for more flexible and comprehensive management of all forms of geological data used in resource evaluation. Driving this program was the information needs of feasibility studies of the Iron Magnet deposit, located beneath the existing Iron Duke and Iron Duchess mines. Prior to the beginning of 2003, resource evaluation drilling data collected by OneSteel was managed using an in-house system based on industry standard relational database software. The system was demonstrably effective in ensuring the fundamental integrity of basic drilling data, but lacked necessary capabilities for the acquisition and management of geological descriptions, geotechnical and geophysical data obtained by down-hole logging. OneSteelÆs existing system for the management and interpretation of geological descriptions was restricted to storage of a single three digit code for each lithological description interval. The original logs for a large number of older drill holes could not be located, having been either poorly archived or culled from the database in the belief that they did not contribute to the understanding of the resources currently being mined. The three digit codes represented a combination of lithological and stratigraphic descriptions, including many subtle variations in iron ore colour and texture believed to be associated with variations in geochemistry, but subsequently demonstrated to be either incorrect or inconsistently applied. This resulted in the establishment of a plethora of codes for a relatively small number of distinct lithologies. Improvements implemented by OneSteel geologists addressed these shortcomings by ensuring the new data management system: facilitated the objective description of lithological characteristics; distinguished between obsevations and interpretations (eg lithology versus stratigraphy); promoted consistency between descriptions provided by different geologists; and helped to ensure data integrity by developing an audit trail for alterations made to data subsequent to its acquisition. The data used to develop interpretations of mineralisation distribution and characteristics are fundamental to the effective utilisation of a mineral resource: any mineÆs most important asset. Resource related risk is widely recognised as the principal source of technical risks affecting resource development projects, whether they are new mines or expansions of existing operations. A key lesson from this work is that most commercial or æin-houseÆ developed geological data management systems are able to handle basic data validation tasks effectively. Geologists, however, need to ensure that the data management system is appropriately structured to help promote the acquisition of objective and consistent data for interpretation.

Jan 1, 2003

By J P. Moodie

Recent trends in flotation technology are briefly reviewed. These show that considerable development has been made as the operators, suppliers and technologists have responded to the challenges of the industry. Most of these advances have been based on empirical and phenomenological methods. There is a considerable opportunity to make further advances through a more fundamental, scientific approach. Some of this work is discussed and, although progress is being made on this front, industrial uptake has been somewhat slow. A number of specific issues facing the industry are discussed.

Jan 1, 2005

By A McRae

Much of western New South Wales is characterised by an extensive regolith formed during more than 60 million years of exposure, weathering and erosion. This cover includes intensely weathered in situ regolith and superimposed transported materials of variable thickness, commonly in complex palaeochannel systems. Mineral exploration in this region has been considerably hampered by the cover, which can complicate or maskgeochemical anomalies and also obscure geophysical signatures. A detailed multi-disciplinary study of part of this region, centred on the Cobar-Girilambone area has demonstrated a methodology for exploring through this regolith. The approach involves regolith-landform mapping to establish the main landscape and palaeolandscape elements and to determine the nature and spatial occurrence of different regolith materials. By combining knowledge of the surface distribution of different regolith-landform units with available 3D information on the regolith and geophysical data it is possible to construct simplified derivative maps or exploration ægoÆ maps, which can be used to advise appropriate exploration strategies or help interpret acquired exploration data. This study has also established the major regolith controls on geochemical dispersion and determined key background element associations. These regolith-related element associations can result in highly variable background levels for many trace elements and need to be understood and factored into the analysis of geochemical data for different regolith sampling media. With better knowledge of the regolith it is possible to select the most appropriate exploration techniques and sampling media for a given area, as well as apply appropriate normalisation procedures to the acquired data. Exploration success can be greatly improved by using many existing techniques in æregolith smartÆways.

Jan 1, 2004

The ore reserves of the Frieda porphyry copper prospect in Papua New Guinea have been estimated using kriging and an alternative method. Only very erratic variograms could be obtained from the raw data and thus it can be expected that kriging variances will be unrel- iable. The frequency distributions of the two sets of estimates show expected differences and the resulting mineable reserves show similar expected differences. More drilling and the use of disjunctive kriging are needed to produce reliable estim- Ates.

Jan 1, 1979

Much of New Zealand is comparatively young geologically in the sense that it has only recently been uplifted. In many places young marine sediments are to be found at high altitudes, as evidenced by the existence in the North Island of Pliocene shell limestones which form prominent escarpments at altitudes of about 3000 ft. inthe central part of the Island, and remnants of the same formation found on the summits of the northern Ruahin.e Range at altitudes greater than 4000 ft.

Jan 1, 1962

Western Deep Levels, a seismically active deep level gold mine, started placing backfill in their narrow tabular workings as part of the regional support strategy in 1986. Over the years the percentage of working places being backfilled has been gradually increasing. At the end of 1995 the support efficiency and the labour productiveness relating to support installation were scrutinised to determine if resources were being optimised. Owing to financial, safety and productivity constraints it was decided to redesign stope support to be less labour intensive, safer and provide an integrated stope support system. This new integrated system will thus combine the previously used temporary, permanent and back area support consisting of mechanical props, hydraulic props and backfill respectively. Backfill previously formed an integral part of the regional support in conjunction with strike stabilising pillars. To design the integrated support system the backfill placement quality has to be exceptionally good and placement must be done as close as possible to the working face. The backfill to face distance was reduced by 30 per cent and in some areas by more than 50 per cent with an increase of square metres filled to increase the effect of the backfill even more. This paper addresses the design and successful implementation of an integrated stope support system based on the optimisation of backfill to the extent where installation of mechanical and hydraulic jacks could be eliminated.

Jan 1, 1998

By Keast-Jones R

The relative merits of treating coal by flotation and spiral concentrators have been examined by tests on run-of-plant fines samples from three seams in the Wittingham coal measures of the Upper Hunter Valley. Flotation of the complete fines was found to be the most metallurgically efficient process with yields substantially superior to those obtained from treatment of only the deslimed fines. A strict comparison between spirals and flotation for the treatment of the deslimed fines was impossible due to differences in product quality. However, the results indicated that the performance of a flotation circuit would be equivalent, and sometimes superior, to that of a spiral circuit.

Jan 1, 1984

The changing characteristics of raw materials has highlighted the limitations that conventional vibrating screens have in the handling of fine wet sticky materials. These' limitations have led to the development of a totally new concept of screening, the Rotating Probability Screen. In order to illustrate the practical benefits to be gained by the extraction of fine materials ahead of subse quent processes particularly in the coal industry, the experiences gained in Ro-Pro installations in America, Australia, Europe and Britain are drawn upon.

Jan 1, 1984

By Crawford J

The paper asks the question 'Why Limit the HYDROTRANSPORT of material to the confines of your washplant'.A brief historical review of widely accepted slurry transport operation establishes that we are not talking about new technology - simply applying proven experience to an innovative continuous system.The paper reviews a simple potential application and compares capital and operating costs with conventional trucking.No attempt has been made to develop a complete mine plan and the comparison has been limited to material transport costs.

Jan 1, 1992

One of the often overlooked factors affecting the capital investment decision in new or existing plants is the value of stock holdings necessary to maintain the plant. This paper puts forward a simple decision matrix on whether a part should be stocked depending on 1. the criticality of the item of equipment in terms of the effect on cash flow of its failure, 2. the lead time of the part, and 3. the stock holding value if it were Stocked.

Jan 1, 1986

By Turco E, Pelizza S, Vona A

Within the project against pollution in the Gulf of Naples (Italy) it was envisaged to build a sewage collection tunnel whose tunnelling section is about 30 m2 and whose length is over 4 km. The formations to be bored through feature heteregeneous volcanic deposits made up of either lenses or lava, lapilli and pozzolan layers and ashstone silts. The cover ranges between 10 and 30 metres. The surface is heavily built-up requiring then an accurate monitoring and reduction of noise, vibrations and settlements. The building of the tunnel is therefore carried out by means of a boom tunnelling machine equipped with a mechanized shield. Support along the complete excavation perimeter is provided by linerplates together with an immediate cement grouting behind them. At a later stage the concrete lining will be cast in place.

Jan 1, 1987

THIS paper is not intended to be a detailed description of the lead, smelting plant at Cockle Creek, as this has been covered in previous papers for the Institute in 1918, Proceedings No. 31, by other members of the staff; but the idea is to give some of the practices and conditions peculiar to these works, also to give some experiments carried out and the conclusions arrived at. Unfortunately, owing to the closing down of the smelting and refinery plant at these works, sone of the experiments could not be carried to a more definite and commercial basis, but they are given in the hope that they may be of interest to members, and may perhaps suggest further thought along the lines indicated.ROASTING AND SINTERINGThe greater part of the ore treated at these works came from the Central mine, Broken Hill, but, in addition, a large quantity was purchased from other parts of New South Wales and from Tasmania. This purchased ore was seldom received in the form of a concentrate, but initially in its crude state, and therefore had to be crushed. The crushing was done in a Krupp mill, and the ore then added to the roasting mixture. This addition of crude ore was one of the main...

Jan 1, 1923

By E Mofya, R Kaunda, P Lever

One of the fundamental requirements for being able to optimise blasting is the ability to predict fragmentation. An accurate blast fragmentation model allows a mine to adjust the fragmentation size for different downstream processes (mill processing versus leach, for instance), and to make real time adjustments in blasting parameters to account for changes in rock mass characteristics (hardness, fracture density, fracture orientation, etc). A number of blast fragmentation models have been developed in the past 40 years such as the Kuz-Ram model (Cunningham, 1983). Fragmentation models have a limited usefulness at the present time because:The input parameters are not the most useful for the engineer to determine and data for these parameters are not available throughout the rock mass. Even if the input parameters are known, the models still do not consistently predict the correct fragmentation. This is because the models capture some but not all of the important rock and blast phenomena. The models do not allow for ætuningÆ at a specific mine site. This paper describes studies that are being conducted to improve blast fragmentation models. The Split image processing software is used for these studies (Kemeny, 1994; Kemeny et al, 1999).

Jan 1, 2001

Major changes occurred in the management of loss prevention and risk management at operations in North and South America due to increased insurance premiums following the Olympic Dam fire in Australia in 2001. There are many different scenarios on how fires can develop and the estimated maximum losses (EML) those fires can incur. The EML is utilised by insurance companies to determine the cost of insurance premiums. The cost of insurance can be controlled at existing and newly designed solvent extraction (SX) plants by using risk reduction methods and design criteria to limit the fire exposure. A review of data collected during several loss prevention risk assessments can show how a budget can be protected from dramatically increased premiums and see which design of SX plant and fire protection standards best apply to your operations. The paper will investigate the pitfalls of existing materials of construction, capacity, geography, management practices, fire risk minimisation, and fire suppression systems. Intelligent engineering and managerial improvements implemented by the operations in the Americas in the past two years have further minimised the fire potential and benefited companies in insurance renewal negotiations.

Jan 1, 2003

By Noller B. N, Mine F. J

Modem open cut and underground mining in the tropics inevitably expose partially weathered and unweathered rocks to oxygen and water, leading to weathering and the release of solutes and often acidity as well. Historical monitoring data can demonstrate these phenomena. Three case studies from open cut mines in the north of the Northern Territory illustrate the deterioration in quality of pond water receiving drainage from waste rock dumps. The potential for deterioration of water quality was not recognised in many mine Environmental Impact Statements prepared and accepted in the 1980s. The examples documented indicate the importance of adequately planning for this near inevitable process. Retrofitting a mine water management system to 'no' or minimal release can be very difficult and expensive, and may not be feasible, leading to downstream pollution. The characterisation of acid and solute production potential of ore and waste rock, and improved dumping strategies and water management are very important to minimise the environmental impact of mining in the tropics.

Jan 1, 1994

By A M. Wala, H W. Wu

A research project incorporating a number of mine site exercises to reduce the effects of fire incidents and possible consequent health and safety hazards has been undertaken focused on the application of mine fire simulation software packages for contaminate tracing and fire modelling in coal and metalliferous mines. This paper examines aspects of introduction of inert gases to underground workings to aid recovery of a mine following a fire. Broad conclusions from work undertaken at individual Australian coal mines are discussed as examples. The effort is built around the introduction of the fire simulation computer program æVentgraphÆ to the Australian mining industry and the consequent modelling of fire scenarios in selected different mine layouts. Case studies have been developed to examine usage of inertisation units and particularly application of the GAG jet engine unit. One example has focused on selection of the best surface portal location for placement of the GAG for most efficient suppression of a fire. A second has examined a situation with significant seam gas being emitted on the face. This has shown that under certain face dip angles stopping the mine surface fan to reduce dilution of GAG exhaust gases will cause reversal of face air and consequent mine explosion as gas laden air is drawn across a fire. A third examines inertisation and dilution issues in mains headings. mains headings present a complex ventilation network with often numerous parallel headings, hundreds of cut-throughs and a variety of ventilation control devices. In such a complex system (with additional interference from a fire), maintaining control of the movement of inert gas is more difficult than elsewhere in the mine. Some illustrations of this issue are given.

Jan 1, 2005