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By Butters S. E, Deslandes J. V

The selection of loading and haulage equipment in a proposed or oper- ating mine is vital in ensuring the cost effective achievement of produc- tion targets. To assist in the evaluation of different haulage systems, a truck haulage simulation model has been developed at BHP Melbourne Research Laboratories. The operation of the model is described and exam- ples of an actual application at Mt. Whaleback Mine is presented.

Jan 1, 1989

The task of designing stable high walls and spoil piles in strip coal mines, and stable openings with controlled roofs and floors in underground collieries - within the constraints normally imposed by economics - depends upon a reliable assessment of rock mass strengths and rock mass reactions under a variety of stress conditions. Of the geological factors influencing internal friction and cohesion within rock masses, many may be determined qualitatively or empirically from bore-hole evidence. Rock types, descriptions and properties of intact rocks, location of boundaries, limits and degrees of weathering, potential for slaking or decomposition of rocks when exposed, bedding characteristics, the nature of rock anisotropy and the likely effects of water on rock mass properties can be assessed from bore- hole data. Discontinuities, whether they be major such as faults and dykes, or minor such as joints and fractures, present a greater problem, and in most instances the mine geologist must resort to additional techniques to describe or predict their occurrence, nature, frequency, intensity or physical properties. Information on ground water and seam gas is available from bore-holes within certain levels of reliability.

Jan 1, 1977

Pulverised coal firing was pioneered in the cement industry prior to the turn of the century. Ash from the coal is absorbed into the mix in the kiln and replaces secondary materials. With high purity limestone coal with high ash content can be used. Fuel cost is a major part of the total manufacturing cost. Cement plants are thus quick to respond to fuel price changes and will use low grade fuels if there is a price advantage. Combustion conditions in a cement kiln differ markedly from a boiler. Flame length is determined by air/fuel mixing but because of fixed secondary air conditions this depends on primary air momentum. Volatile content has some effect on flame length but this can be offset by coal fineness. Much of the heat for cement production is for limestone calcination which is a low grade energy requirement. By allowing long residence time in separate direct fired vessels which then feed the high temperature kiln the energy of materials such as oil shale, tyres and lump lignite can be utilised.

Jan 1, 1987

By P J. A Lever

This paper presents details of CRC MiningÆs work with waterjet assisted blasthole drilling. The objective of this work was to investigate techniques that reduce the cost and increase the productivity of blasthole drilling. The focus is on a technology that uses a high pressure waterjet to assist the conventional rotary rock cutting action of a tricone drill bit. The potential benefits of this technique are increased productivity, reduced drill bit wear and reduced hole deviation and hence improved quality of drilling. This paper describes the results of a laboratory based experimental program comparing conventional tri-cone drilling performance to the proposed waterjet assisted approach. Additionally, work has been completed looking at the more practical issues around the collection and sampling of drill cuttings and water recovery (recycling) when drilling with a waterjet. These studies have demonstrated that waterjet assisted drilling can significantly increase the rate of penetration over conventional rotary drilling. For the best-case experimental result, the relative improvement was over 40 per cent. More importantly, it is a starting point for examining alternative uses of the additional drill productivity obtained from waterjet assisted drilling. For example, increased drill productivity could be used to improve rock fragmentation by drilling a tighter blasthole pattern in the same time period. an existing drill fleet, then the drill fleet size could be reduced, or improved rock fragmentation could be achieved by drilling a tighter blasthole pattern within the same time period.

Jan 1, 2004

By M Roberts

The aim of this paper is to evaluate the technical feasibility of application of the electric monorail as a haulage system in hard-rock underground mining in Australia, in comparison to conventional truck haulage systems. The elements of the system being investigated include mine design and layout, installation, loading and unloading subsystems, tramming speeds, cost and productivity, automation, ground support, safety and environmental factors. Electric monorail systems are potentially more cost-effective due to a range of factors: only the one system may be needed for the transportation of workers, material and rock; and excavations for monorail haulage can be smaller and mined at much steeper gradients than for truck haulage. The smaller excavation size also reduces the need for costly ground support and û in another important measure for the health and safety of mine workers, and for energy savings û it reduces ventilation requirements. Electric monorail haulage technology is being applied in hard rock mines in South Africa and considerable benefits have been realised by the industry in that country. In Australia, mine designs for metal mines generally remain based on truck haulage and/or shaft hoisting systems. There is a tendency to apply these haulage systems to every orebody. For the industry to achieve sustained growth against a backdrop of volatile diesel prices and environmental concerns, new generation underground haulage systems are required. The monorail haulage system offers opportunities in improving materials handling efficiencies in underground mining operations. This paper examines the application of monorail haulage in metalliferous underground mining, presents comparative data with track and trackless haulage systems and develops concepts for system application in combination with conveyor belt haulage and narrow vein mining situations.

Jan 1, 2005

By Mauk JL, Arehart GB, Mathews SJ

The banded nature of the quartz veins which form the Empire lode at the Golden Cross mine, is perhaps their most striking feature. Petrographic studies show that significant differences occur between the bands in terms of textures, quartz grain size, calcite, adularia and kaolinite content, and the form, concentration and mineralogy of sulfide phases. The 818Oqu i values of individual bands within the vein material range from 7.3-10.9%x. Calculations show that the 818Oqäa,u values can be adequately explained by temporal variations in the system temperature, boiling and/or variations in the systems fluid/rock ratios.

Jan 1, 1995

By Lunarzewski L, Truong D

Although there are sound principles used in the world recognised methods of gas emission prediction, results based on these methods applied to several Australian longwall extractions have yielded unacceptably high discrepancies. With the development of mining in new seams and at higher rates of extraction, the need has grown for a methodical approach to predicting gas emission levels specifically for local Australian mining conditions. Such an approach is developed from results of recorded emission readings during longwall mining at Appin and Pacific Collieries over the past 6 years.

Jan 1, 1988

King Island is situated at the western approach of Bass Strait and approximately mid way between Victoria and Tasmania. The scheelite orebodies lie within the south east of the island. Ore bearing horizons from 10 m to 40 m thick occur in south and east dipping stratiform deposits. The orebodies occur in skarn formed by contact metasomatic replacement of carbonate rocks by granite intrusives. The scheelite is deposited as fine disseminated grains in and along the margins of andradite garnets in the skarn. King Island Scheelite operates two under- ground mines from which 350 000 tonnes per year are obtained. The Dolphin mine produces almost two-thirds of the total. See Figure 1. The Dolphin orebody lies beneath the sea and an area of reclamation. The orebody is inter- sected by zones of major dislocation. A chequerboard post pillar cut and fill stoping system has been chosen to provide the necessary support to the hanging wall. Because the stability of the pillars is critical to the economic welfare of the mine, considerable attention is given to the reduction of overbreak.

Jan 1, 1977

By M J. Pascoe

The performance of 460 stope surfaces at WMC ResourcesÆ Olympic Dam Operation (ODO) has been used to investigate the confidence that can be placed in the Stability Graph Method for design of stope dimensions. A detailed database of stope performance and ground condition information was established for each stope. The database contains all the required stability graph information as well as other factors thought to influence stability, such as discrete major structures, poor shape and exposure time. The performance of each stope surface was quantified by calculating Equivalent Linear Overbreak/Slough (ELOS). The performance of stope walls and crowns was plotted on the supported and unsupported case history stability graphs. Based on this information an ODO design limit of HR = 3.3 x NÆ0.33 has been suggested for stope walls. Walls that plotted above this line were 80 per cent stable, 20 per cent unstable and zero per cent failed. Below the line 60 per cent were stable, 30 per cent unstable and ten per cent failed. Supported crowns that are flat or arched in shape and are not within the influence of major structures can be designed in the stability graphÆs æstable zoneÆ with a strong likelihood of stability. The Stability Graph Method did not reliably predict the performance of unsupported crowns at ODO.

Jan 1, 2005

By K Williams

Marvel Loch South Pit has had a number of stages of open and underground mining activities before acquisition by Sons of Gwalia. The historical pit had achieved a completed pit depth of 150 metres and the shaft and decline mine had reached approximately 220 metres in depth using open stope mining methods. The various mining methods reflect the various economics and industry practice at the time. The South Pit ore zones are medium grade (~2.5 g/t) but have a regular geometry and large tonnes per vertical metre. A number of studies have been completed up to a pre-feasibility stage looking at options to extend the pit depth and to lower the unit cost of gold production. The options considered were the re-optimisation of the pit to determine further cutbacks or the innovative use of an in-the-wall ramp. The in-the-wall ramp (tunnel) would permit the removal of the in pit ramp to expose additional ore that was within the footprint of the ramp design and to provide the opportunity to increase the final pit depth. Similar mining method has only been used at Three Mile (Coolgardie, WA) and Chalice Mine (Norseman, WA). The tunnel would serve as a gateway for further extension of the south mine and the central ore zone via underground mining methods. The ultimate depth of the South Pit has been extended to 310 metres below surface and significant additional ore has been recovered. This paper will give an insight into the various studies to optimise the Tunnel mining method, the determination of the various tunnel dimensions, and the phases of mining to arrive at the completed design.

Jan 1, 2003

By P Voigt, B Lumsden, P Lines, I Gurnett

Plant tests of magnetic conditioning have shown increased flotation recovery of paramagnetic sulfide minerals (chalcopyrite, sphalerite and pentlandite) in the -38 ¦m size fraction within rougher and cleaner flotation circuits. A statistical plant test was undertaken in the Mount Isa zinc flotation circuit where magnetic conditioning was tested simultaneously in both the rougher circuit and the cleaner retreat circuit (cleaner scavenger). This test resulted in a normalised increase of 1.60 per cent in the rougher circuit zinc recovery and simultaneously a normalised increase of 4.60 per cent in the cleaner retreat circuit zinc recovery - to a very high level of statistical confidence. Interestingly, in a novel approach, it was possible to verify the plant test results in two ways. Firstly, detailed MLA analysis of the tails confirmed the statistical plant test results and showed that the greatest effect of magnetic conditioning was on the sphalerite in the C3 - C6 size fraction, where there was a reduction of around 15 per cent in zinc in tails. Moreover, there was a reduction of around 15 per cent in liberated sphalerite across all -38 ¦m size fractions, but only a seven per cent reduction in non-liberated sphalerite in the tails. Secondly, plant modelling showed that increasing the rougher zinc recovery would cause an increase in zinc feed grade to the cleaner retreat circuit. The increase in the zinc feed grade to the cleaner retreat circuit with magnetic conditioning was demonstrated to a very high level of statistical confidence.CITATION:Gurnett, I, Voigt, P, Lumsden, B and Lines, P, 2012. Magnetic conditioning of sphalerite at XstrataÆs Mount Isa Zinc Operations, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 233-240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Thiel D. V

It is quite well known, although not so well documented, that radio noise is generated during rock fracture. Radio noise has also been observed during severe earthquakes. The source has been thought to be the fracturing of the rock, although the mechanism has never been unequivocably proven. A study of these radio emissions may provide insight into rock dynamics prior to seismic events, and after blasting. A programme of electric-field recordings has been undertaken at Brisbane quarries during multi-hole blasting. Preliminary analysis has shown that three types of signal may be distinguished. They are hole detonation, rock fall and post blast relaxation signals. It is thought that information about the blast, and the fracture of the rock, may be ascertained from these Signals.

Jan 1, 1990

After the minim operation, most raw materials that occur in the earth's crust require some form of processing or refining before they can be converted into a final end product. In the mineral industry these remarks apply to materials such as iron ore, bauxite, limestone, copper ore and many others that are found in Australia in large quantities. Processing plants for these raw materials operate more efficiently, however, if the feed to them is consistent in both physical and chemical characteristics. Such uniformity rarely occurs in nature so that some form of homogenisation, or blending, is required ahead of the processing plant. Bending also assists the mining operation itself by reducing; the need for selective mining and, by combining high and low grade materials, a more uniformly graded, commercially acceptable product can be obtained, thereby increasing the commercial life of a mine or quarry. Bed blending is the most efficient of the processes available, and following its development in the United States in 1905, over 100 plants have been installed, or are under construction, all over the world. The original process, the Robins--Nessiter system, has been the subject of continued improvements and refinements, so that economical capacities are possible from less than 100 l.t.p.h. up to 10,000 l.t.p,h. and beyond.

Jan 1, 1969

Surface subsidence caused by coal mining operations was the subject of a very successful symposium organised by the Illawarra Branch of the Australas- ian Institute of Mining and Metallurgy in February, 1973. This symposium dealt with the principles of subsidence and overseas experiences arising out of underground mining. Since that time the i eew South Wales Department of Mineral Resources and Development (formerly the Depart- ment of Mines) has incorporated in the approval for pillar extraction certain conditions related to the monitoring of surface movement. Surveys and plans are required to be kept at mines where total or partial extraction of coal takes place. This paper traces the monitoring of surface movement in the Northern Coalfields of New South Wales over the past ten years. Reference is made to the National Coal Board's Subsidence Engineers' Handbook (1975) and how the guidelines expressed therein have been Beneficial.

Jan 1, 1980

The South Comet mine is an underground silver-lead-zinc mine located on the West Coast of Tasmania with an annual production in the order of 35 000 tonne per year. All ore mined is shipped to the Rosebery mill by road, a distance of 17 km.

Jan 1, 1993

By Royston, Woods R

ANI Bradken Vortex Pulp Lifters and Grates, both as original equipment and retrofitted to existing SAG mills, are now in field operation. The development of the Vortex leading curve pulp lifter was based on an analysis of traditional radia

Jan 1, 1997

By Yao S, Wang P, Zhang C

The Zhilingtou Au-Ag deposit is situated in the eastern part of the complexly deformed and metamorphosed South China Caledonian Fold Belt. It consists of seven orebodies that are almost exclusively hosted by biotite plagioclase gneiss of the Precambrian Chencai Group. They form an apparent en echelon pattern in both cross-section and level plan. Three different ore types, based on mineralization textures, have been recognized within the Zhilingtou lode. These are Au-Ag-rich quartz veins, Au and Ag-bearing silicified rocks and Au-Ag-containing altered rocks with quartz stockworks. The mineralization is principally composed of electrum, argentite, pyrite and minor sphalerite, galena as well as traces of hessite and chalcopyrite plus a gangue assemblage of quartz, rhodonite, sericite and chlorite. Fluid inclusions related to Au-Ag mineralization yield a wide range of homogenization temperatures from 110 to 447¦C, with two distinctive peak values at 250-300¦C and 350-400¦C respectively. S30Si values of quartz veins and silicification from the three stages of mineralization range from -0.1 to -0.4%o. The mineralization at Zhilingtou is interpreted as forming by recirculated meteoric water extracting ore-forming elements from metamorphic rocks due to Mesozoic volcano-magmatic activity.

Jan 1, 1995

By Watters R

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 Harper B

The mining industry has developed a comprehensive view of the need to have production personnel well trained in the use and maintenance of mining equipment. A strong commitment from the industry to this view has been instrumental in creating an efficient, profitable and productive industry based on modem production processes, sophisticated equipment and a multi skilled workforce. As the industry continues to develop, and the skills and knowledge needed by productive workers continues to expand, the training processes adopted by the industry will need to develop in parallel, not only making use of the latest advances in learning theories, instructional design and technology, but also using these knew ideas in more efficient ways.

Jan 1, 1998

By Sloan GJ, Lysnar RD

Since the of Bergstrand's Geo-dimeter in 1946, and Wadley's Tellurometer in 1956, there have been numerous Electromagnetic Distance Measurement (EDM) instruments produced throughout the world by a variety of companies.This form of measurement has not merely replaced other methods of measurement, but has caused considerable change of emphasis in survey techniques. Major control surveys are now being accomplished using trilateration instead of triangulation. The surveying of open cuts or engineering work may be done in a fraction of the time and, in the majority of cases, to a greater degree of accuracy than with older methods.It is surprising that with this new tech-nology and development of EDM equipment which is compact, easy to use and no longer so expen-sive, no advance has been made in underground surveying. If we look at equipment being used by the majority of mining companies, we see that there have been very few changes since the Second World War. Very little research has been carried out to enable the surveyor to do his work more easily in conditions which, at the very least. are hazardous.

Jan 1, 1984