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Contract mining is an integral part of the underground and surface hard rock mining industry in all states of Australia. Contract mining is now makes a major contribution to the opencui coal industry in Queensland and New South Wales with Thiess alone producing over 16 million tonnes per annum with safety performances that most coal companies would be proud of. Contract mining is now attracting interest in the underground coal sector.

Jan 1, 1998

The environment under discussion is that of the sandy coastal plain and adjacent offshore sandy islands. The environment is the result of natural forces of the past which moulded it. Only very recently have men and machines participated in this moulding. The future of the environment - the changes which it must undergo - is in the hands of natural forces with, presumably, man's continued participation. In essence, we are concerned with the forces operating on a mass of sand.

Jan 1, 1971

Thermo Fisher Scientific is a supplier of samplers, instruments, analysers and consumables to the mining industry under the Thermo Scientific brand. The critical need to provide a representative sample to the analyser has played a pivotal role in product development. Products discussed are the Analysis and Sampling Station (AnStat) for mineral slurries, the Coal Quality Manager (CQM) and the prototype Bore Hole Analyser (BHX) with optional drill chip recovery system. Analytical techniques used in the above products are XRF, PGNAA and LIBS respectively. The company also designs and supplies conventional mechanical sampling equipment and complete sampling systems for bulk material applications (historical Ramsey brand). These products and application of them are presented.

Jan 1, 2008

By Forssberg KSE

Purification of GAsgruvan Limestone is carried out by anionic, cationic and cationic followed by anionic flotations in order to obtain a calcite concentrate that is acceptable to the paper industry. The results indicate that such a concentrate could be achieved by first carrying out the separation of siliceous gangue minerals by cationic flotation followed by the separation of carbonate during the anionic flotation. Stearylamine acetate (Flotigam SA) and a modified fatty acid (OMC 357) are found to be selective during cationic and anionic flotation, respectively. A final product containing 99.25 per cent calcite with a recovery of around 80 per cent is obtained. It is hoped that these results could be further improved by the follow-up process variable studies, in particular, the effect of reagent dosages and conditioning time at each stage of cationic and anionic flotation steps.

Jan 1, 1993

By Cecala AB

For 20 years the US Bureau of Mines has been researching strategies for improving the physical, social, and psychological work environment of the miner. The products of this program have shown that a consistent link exists between safety and productivity, and the key to this link is the use of effective human factors and management practices. There are specific research findings from the research projects of the Bureau on ergonomic design of mining equipment, redesign of tasks (especially materials handling) to minimize back injuries, human resource management techniques for increasing safety and productivity, and improved shift rotation schedules. Current research is continuing these themes with new applications to high technology mining systems, including computer assisted extraction devices and mine monitoring.

Jan 1, 1991

A major problem with many items of underground equipment is that they have either been converted or adapted from surface equipment, or that they have been designed and assembled in comfortable offices and factories with adequate lighting, specialised tools, and ample space. As soon as they are in use underground in cramped spaces maintenance frequently becomes difficult, parts are awkward to change, and a whole range of accidents can happen.Similarly, ingenious operators discover a whole range of uses for which the equipment was not designed, such as using a loader bucket for a work platform, or scaling backs with it.Design modifications of equipment and removal of hazardous components that can trap limbs is expensive when the dangers are discovered in operation, sometimes posthumously, and it is not surprising that workers compensation insurance premiums are high. The cheapest place to ensure that equipment is safe is in the design office, where the operator should be considered first, rather than being added to a purpose built machine as an afterthought.

Jan 1, 1992

The efficiency with which it is expected that a particular coal may be burnt in a power station boiler significantly affects the value of the coal. Consequently many laboratory tests have been developed to provide data on the combustibility of coal. Computer modelling of coal combustion has also provided insight into limits on coal burn- out. Such modelling suggests that burnout of bituminous coal in a power station boiler will be strongly influenced by physical limits on the diffusion of oxygen to the individual coal particles. Coal chemical reactivity appears to be relatively less important. As a consequence of the diffusional limits, significant improvement in burnout is achieved either by producing less large p.f. particles or by providing sufficient furnace residence time to burn the large particles. Field data from a variety of power stations supports these cn.clusions. Burnout was also found to correlate well with volatile content for a number of coals from widely different sources. This is expected as the high vola- tile coals produce less residual char to be burned by the relatively slow heterogeneous Combustion.

Jan 1, 1987

Although geophysical methods of prospecting have proved indispensable in the search or oil deposits elsewhere; it is only 'in recent years that they have been used to any significant extent in Australia. The increase in their use has been quite remarkable over the past two or three years, due in Sao small measure to the encouragement given by means of Commonwealth subsidy. There is no doubt that the use of' geophysical methods will coxi-tinue to increase and this increase could be greatly accelerated as and when oil is discovered in commercial quantities,This review of their use A in Australia and the remarks and statistics are confined to work on the mainland. There has been, a substantial amount of geophysical work in Papua, but as operating conditions are so very different to the mainland Papua has been regarded as a separate province.

Jan 1, 1962

Dewatering tailing slurries by mechanical means is often not possible and gravity and solar driven processes must be used. It has been shown previously that better use of gravity is achieved when the tailing is drained as it settles. Not only are more compact sediments obtained but also the dewatering is faster. From the results of laboratory and field tests reported here, equations were established which describe the evaporation and drainage components of the dewatering. These equations were used to calculate the effects of ponding depth, solids content of the tailing and clim- atic conditions on the time required to dewater the tailing. Since the calculations can be made with and without the drainage component, the advantages to be gained with drainage can be determined. The tailing used in the work was a clay slime from a sand washing operation. However, it is anticipated that this approach will be applicable to other similar tailing.

Jan 1, 1978

Against a background of deeper pits, the introduction of prestripping fleets and the need for closer control of operating costs (especially the waste removal component), Australian coal operations utilising draglines have in recent years become increasingly focused on:1. assessment of more efficient excavation methods; and2. application of explosive products and initiation systems which offer more flexibility than ever before.Additionally, developments in blast performance assessment techniques and equipment, and computer modelling and excavation monitoring systems have provided an improved opportunity to design a blast to achieve a desired profile suited to the excavation equipment and Sequence.

Jan 1, 1992

By S Furman, M Caccetta, A Hacket, B McDonald, M A. Wells, D Lau

In 2004, the Western Australian Department of Industry and ResourcesÆ Burrup Rock Art Management Committee commissioned a number of independent scientific studies to evaluate the condition of rock art in the Burrup Peninsula near Karratha (Western Australia). These studies are evaluating the physico-chemical aspects of the effect of environmental modification on the visible appearance of the rock art. Because of the cultural significance of the sites, the research approach has been to employ non-destructive testing strategies and work in the field has progressed with respect for the importance of the area. This paper only reports the spectral mineralogy monitoring at each of the sites to evaluate whether changes in mineralogy are observed on rock surfaces. Reflectance spectroscopy is a non-destructive, in situ materials characterisation technique that provides information about the mineralogy. The minerals detected include haematite, kaolinite, chlorite, goethite, gibbsite and manganese oxides. Current results indicate that the surface mineralogy of the rock art has not changed in the last four years.

Jan 1, 2008

The impact of moves to introduce Abori- ginal land rights was felt in the Northern Territory as early as 1972 when the Federal Government froze the processing of all appli- cations for mining interests over vacant Crown land. The Aboriginal Land Rights (Northern Territory) Act was finally proclaimed on Aust- ralia Day 1977 and since that date the mining industry and the Territory legislature have struggled to make the Act work. Despite these efforts long delays have been experienced by those required to negotiate mining and explor- ation agreements under the Act. In fact explor- ation on Aboriginal land has been effectively stiffled since the introduction of the Abori- ginal Land Rights Act. The Northern Territory government and the mining industry have both sought amendment to the Act to remedy some of its more onerous problems. These efforts have generally been fruitless. Some of the recommendations put forward by Mr Justice Toohey following his recent review of the Act would provide relief in some important areas. However, any such improvements are more than offset by a number of Mr Justice Toohey's recommendations which would severely disadvantage the vast majority of Territorians. A recent survey of mining companies seeking exploration licences over Aboriginal land indicates that many of the existing diffi- culties could be overcome without significant amendment to the Act but rather by the adoption of a positive administrative approach by the Land Councils. It is now up to the Commonwealth and the Land Councils to demonstrate that their Act can work without crippling the Northern Territory economy and its mining industry.

Jan 1, 1984

Mining of the silver-lead-zinc orebodies at the George Fisher Mine officially started in 2000. A review of mining performance to date shows that many of the extracted primary stopes have experienced some degree of hangingwall dilution. The degree of hangingwall failure in the stopes became progressively more extensive throughout mining of the orebodies in 2001 and 2002, culminating in the unplanned catastrophic failure of the 744D stope in which the ore between 13C (2683RL) and 12L (2714RL) sublevels caved into the previously mined cavity between 13L (2654RL) and 13C sublevels. This was followed several months later by another unplanned caving event in a nearby stope, 740D. As a direct result of these unplanned failures it was decided to mine the stopes with a smaller span than had been previously planned and in a primary-secondary pyramidal stoping sequence. To limit the exposure of the stope hangingwall, a hangingwall drive is no longer developed and therefore geologists no longer have access to the detailed geological information that this provided. Geologists at George Fisher Mine have had to be adaptable and flexible in response to these proposed changes and rely more on data from drilling than mapping for their geological interpretation. The result is that the drilling cycle has become much more critical in the planning process.

Jan 1, 2003

Autocompression and virgin rock tempera ture have a marked influence on the ventilation of the lower levels at North Broken Hill Limited N.S.W. To maintain comfortable working temp- eratures without penalty to working hours, increase in airflow or the cooling of the work area is necessary. The use of refrigerated air cooling is discussed. Ventilation of underground mining opera tions at North Broken Hill Limited is accomplished by downcasting air through No.3 shaft, the main operating shaft, 1581 m deep, with additional air through No.1 shaft (542 m) 2 and No.2 shaft (978 m), both no longer opera- tional shafts. Air is upcasted through No.3 ventilation shaft which is 4.9 m diameter and concrete lined, from the No.28 level (1140 m) to the surface. On the surface level of this shaft is a horizontally mounted Richardson 4800 mm diameter single stage axial flow fan with adjustable pitch rotor blades.

Jan 1, 1977

By Medhurst TP, Trueman R

The aim of the paper was to model numerically some aspects of the extraction of coal pillars by split and fendering. A two-dimensional elasto-plastic plane strain model with strain softening and interface mod- elling was used. The model was able to simulate the improvement of conditions experienced in lifting from the fender, when the roof adjacent to the fender has caved. In contrast, when a stook was left, providing support to a span of uncaved roof, the model pre- dicted the fender would suffer considerably more de- formation and strain.

Jan 1, 1992

Mine planning is difficult. Even for small operations, it involves reasoning with complex variables and the practical difficulties of mining. It is also about predicting and planning the future in an unpredictable physical and economic environment. Yet we rely on a handful of individuals and their spreadsheets to tell us how to do it û planning the business and activities of mining to hopefully produce results that will please stakeholders. Does it work? Not as well as it could. Planning affects everyone in the organisation. Company executives are demanding more reliability and stability in cost and revenue forecasts from their operations. Management want to explore ways of being more cost effective. Miners and contractors want more useful plans and realistic targets. And the planners have to describe the method that will translate business objectives into implementable plans. Even with the use of computer technology a lot of effort is expended to produce plans that are largely qualified by the level of knowledge and experience of individuals. Better use of information and the application of Intelligent Technologies can improve the quality and reliability of mine plans and schedules. By capturing the knowledge within the organisation and speeding up the planning process, Intelligent Technologies allow more options to be considered more rigorously. But it is not just about technology. It is about how technology is implemented and embodied in the way the business is managed for performance. When this happens, the real benefits of better planning start to flow.

Jan 1, 2003

By Yushan Ma, Jiqing Wang, Hanyi Jia

The Hedong Gold Mine is located in the Yantai area, Shandong province, China. It is an underground mine with an annual gold output of some 700 000 grams. The orebody is located on the edge of the Wanger Shan metamorphism zone, and the hangingwall of orebodies is thus defined by a prominent set of fractures. The proximity of the metamorphism zone and the inclusion of the fracture set ensure that both the orebody and the country rocks are unstable. The main orebodies dip at an angle of between 40 to 45¦, with a strike length of 160 metres and a horizontal width of 50 metres. Surface subsidence in the area is not permitted. Cut and fill mining is usually practiced. As the mining operation proceeds to greater depths, the ore grade is diminishing and it is necessary to find a more efficient stoping method. Sublevel open stoping with sequential extraction and filling of each sublevel has been designed and applied in situ. This new mining method is called æsublevel open and fill stoping methodÆ in the mine. Experience to-date is that new mining method is satisfactory.

Jan 1, 1998

A blast is designed to completely break competent rock such that it can be economically extracted, and efficiently handled or processed. Efficient breakage of the rock is critical to the success of an operation, and in many operations blast design is optimised to achieve fragmentation, muckpile profiles, and material that is easily excavated. There are inevitably other issues, such as damage to adjacent rock, that should be taken into account when designing a blast to achieve overall optimisation. Some of the key issues with respect to the integrity of the in situ materials adjacent to a blast are identified and briefly discussed in this paper. The potential for damage and the effects of a blast will be strongly influenced by the rock mass properties. This makes it important that site specific conditions and their response to blasting are known. Practical techniques that allow the disturbance adjacent to a blast to be measured with minimum disturbance to operations are described in the paper. Experience shows that, during the blasting process, there is considerable potential to disturb the in situ rock mass adjacent to the blast. In some circumstances a very important objective must be to minimise disturbance outside of the immediate blast area. Measured and observed disturbances caused by blasting to adjacent rock, for various common types of blasting, are discussed in this paper. Blast induced disturbances to the rock mass have been observed in both the near and far fields. These disturbances have the potential to impact on geotechnical design. The geotechnical significance of blast disturbance on a rock mass that is to remain in situ is explored and suggestions with respect to design are given.

Jan 1, 2004

By S P. Suthers, J M. F Clout, J J. Campbe

An advanced technique for modelling hydrocyclone separation performance has been developed. This technique is based on the combined modelling of hydrocycloning parameters and ævirtualÆ iron ore feed. The virtual feed modelling was performed using a novel (in-house) software package called æRecognitionÆ, which uses data from optical image analysis to classify the particles in certain size fractions according to total iron content and calculates data for every grade class. These data include the average mineral composition and density of every liberation class in every size fraction. This information about every size fraction, representing the ævirtual feedÆ, was input to the mineral processing modelling package USIM PAC. The hydrocycloning process was then modelled for this virtual feed using the Plitt hydrocyclone model. Empirical calibration coefficients for the hydrocyclone model were calculated using an optimisation procedure in Excel. Pilot-scale hydrocyclone beneficiation experiments were performed on an iron ore blend, using different hydrocyclone pressures and per cent solids in the feed pulp. These experiments were modelled and the modelling results were compared with the experimental results. The new modelling approach enables prediction of the recovery of each mineral in the products, calculation of the total iron grade and recovery, and optimisation of iron ore beneficiation using hydrocyclones.

Jan 1, 2005

By Collins J. L, Fytas K

Surface mining accounts for more than 50% of the world's total mineral production. In future years this status is expected to change somewhat in favour of surface mining. The production technology during the past decade has concentrated on greater degree of mechanization with high capacity heavy duty equip- ment. This trend will continue. Next two decades will also see microproces- ,or based equipment, health and performance monitoring and management information systems fully integrated with excavated and material handling systems which in themselves will be amenable to auto- matic and remote control. Computerized mine planning will also be integrated within the system providing a fully integrated planning, excavat- ing and materials handling system. The surface mines of the 1990's and beyond will be so computer dependent that manpower will be reduced to one third of current levels.

Jan 1, 1988