Search Documents

The advantages of coordinate geometry in design and construction of underground works are apparent for reasons of flexibility, security, computer operations, survey error analysis, and the use of numerical techniques for setting out and checking works. Integration with National or State survey systems is useful in the long term, both at design, construction and future works stage. Equipment and methods are available which permit "absolute" monitoring of structures and strata over long periods,to close toler- ances. This work can be carried out in the limiting urban environment. Rapid data acquisition by semi-automatic devices, or photogrammetry, utilizing electronic data processing is capital inten- sive, but provides more data than analogue surveys (i.e., setting out centre lines) and becomes more attractive with increased labour Costs.

Jan 1, 1976

By S Williams

The primary objective of most mining projects is to maximise the value delivered to the companyÆs shareholders. Achieving best practice performance and maintaining competitive advantage through low-cost production and high productivity is essential to achieving this aim. Benchmarking is an essential tool for the identification and implementation of best practice performance, and to realise continuous improvement by ensuring best practice becomes common practice. But to be successful, that is to deliver long-term value creation, benchmarking must be holistic and align operational performance with strategic intent. This paper outlines a rigorous and structured approach on how to conduct a successful benchmarking program that aligns operational performance with the businessÆs goals. Further it investigates the benefits that benchmarking can provide throughout the project life cycle and provides some key learnings from some of the worldÆs leading miners.

Jan 1, 2009

By Williams D. J

The boundary element method is one of a number of tools that have found wide application in geomechanics for mine design and stress analysis. Two examples are presented in this paper, illustrating the use of the boundary element method to find potential problem regions in large-scale excavations. These examples are from a Papua New Guinea open cut mine and an Australian sub-level caving operation. Because of the scale of the mines and the complexity of the excavations, the boundary element method is the only practical numerical modelling technique to account for the major influences. Although the boundary element method uses only linear elastic models of the rock mass, the paper illustrates techniques for dealing with non-homogenous and anisotropic rock masses, as well as clasto-plastic effects associated with an excavation.

Jan 1, 1995

By Biao Q, Mizuta Y

Thermal constants such as thermal con- ductivity and thermal diffusivity of rock and coefficient of heat transfer of airway wall are the most important characteristic values which decide accuracy of prediction calcula- tion. However, quality of rock is not homoge- neous and water content in rock varies with location and so, a method for in-situ measure- ment of thermal constants must be taken in. The method developed by us is to measure in- situ rock temperatures at two different depths from airway wall. It is simple and we found its accuracy is good enough in the engineering Sense.

Jan 1, 1988

By Phillips RN

Semi-confined, trachy-andesite sills which overlie the German Creek Seam, within the critical tensile strain zone, form major groundwater hazards to longwall mining at the German Creek underground mines. The water contained in these aquifers is normally neutral, but highly saline. Techniques used to detect aquifers include routine air-lift pumping in exploratory drill holes, downhole geophysical and geological logging and upstage packer testing. Hydraulic constants are calculated from pump-out and pump-in test results. Hydraulic parameters for the calculation of mine inflow rates are determined from pump-out test results because these tests appear to be more representative of aquifer drainage during goat dewatering than pump- in testing. During mining of the first longwall block at Central Colliery, caving fractures intersected overlying aquifers after the longwall had retreated 40m, and mine water inflow rate rapidly increased from less than one litre/sec to 25 litres/sec. The amount of water pumped out of the mine during first panel extraction was 140 megalitres with drawdown occurring over an area of 168 hectares. In the Southern Colliery area approximately 324 megalitres of highly saline water which is actively stored in the Aquila Sill area will be pre-drained from six well points prior to longwall mining. With effective pre-drainage from surface drill holes, maximum inflow rate into the mine during initial goafing can be reduced from 165 litres/sec to about 45 litres/sec.

Jan 1, 1988

The Copper Concentrator at Mount Isa Mines Limited treats approximately 6 Mt of chalcopyrite ore annually. The ore is currently sourced from the 1100 and 3000 orebodies at Mount Isa. Chalcopyrite is the only significant copper bearing mineral, with pyrite, quartz and dolomite being major gangue minerals. Ore is typically 10% chalcopyrite, 11% iron sulphides and 79% non-sulphide gangue. Copper ore is treated through two autogenous mills, two ball mills and a flotation circuit. The autogenous mills replaced a crushing plant, two rod mills and two primary ball mills during 1991. For routine analysis of concentrator performance, composite samples of mill feed, final concentrate and tailings are generated every 4 week period. All samples are sized and size fractions are assayed. Recovery of mineral species to the concentrate are then calculated for each size fraction. Sometimes liberation analysis was also performed by QEM*SEM (Quantitative Evaluation of Material by Scanning Electron Microscope).

Jan 1, 1990

EnergyAustralia is a state-owned corporation in the state of New South Wales, whose responsibility includes ownership and management of an electricity distribution network. Expansion of the high voltage distribution network in the Sydney central business district (CBD) includes the requirement to run an additional five 132 kV feeders over 1.7 km from south of the CBD to a new 132 kV substation in the northern section of the CBD. A driven tunnel is currently being excavated in Sydney sandstone beneath Darling Harbour to contain the new 132 kV feeders. Tunnel construction methods involve both roadheader and tunnel boring machine (TBM) excavation. This paper describes the design development of the cable tunnel, discusses the use of a geotechnical baseline report as an integral part of the contract documentation and provides an update of the current construction works.  

Jan 1, 2008

Sampling and sample preparation systems at the Hamersley Iron Pty. Limited port of Dampier, W.A., were developed for two separate objectives. 1. The need for rapid determination of physical properties. On stream size analysis enables lump ore and pellet- ized ore physical properties to be monitored and controlled whilst shiploading is in progress. As a control procedure this facility allows optimum shiploading rates con sistent with physical quality control. 2. The need for accurate chemical analysis. Chemical analysis on ship- loading forms the final link in overall quality control procedures encompassing the operation of mining, railway and port blending. Thus maintenance of specification products with minimum variation in chemical characteristics is ensured.

Jan 1, 1976

A model of dense medium cyclones is developed based on balancing the terminal velocities of the discrete particles due to the centrifugal force against a random turbulent eddy velocity. An expression of the form P - or Q _ 1 100 e."A where P is the partition number., is a function of cyclone efficiency, particle size and density differential between the particle and medium, and is the slurry spilt, is developed and may be used for regressing plant partition data. The above model provides an understanding of peculiarities of the partition curve such as asymmetrical tails, elevation of the cutpoint and elevation of the d50 with increasingly fine feed. The effect of feed variables such as particle size, medium viscosity and changes in spigot or vortex finder diameter is shown. A means of convoluting the partition curve with various feed washabilities is discussed together with how the above may be used to evaluate plant performance for a variety of feeds.

Jan 1, 1987

By P D. Williams

The Phoenix mine is one of NewmontÆs open-pit operations located in Nevada. Mining started in 2005, with the mine producing gold, copper and silver. The mine life is about 20 years. The gold grade estimation uses the Newmont in-house indicator kriging approach to handle the high variability in drill hole composite grades and support mining selectivity. Each block contains up to 200 subblocks with different gold grades. A flotation mill is designed to process oxide and sulfide ores, recovering gold, copper, and silver. An additional copper leach process is currently under study to process low gold and high copper oxide material with low copper recovery in the mill. The metallurgical recoveries and processing costs are dependent on many variables including rock formation, metallurgical domain, cyanide soluble copper and sulfide contents. This paper describes the Newmont in-house indicator kriging procedures and the revenue based mine planning software system implemented at Phoenix mine to address the complexity resulting from multi-process, multi-metal and indicator kriging model.

Jan 1, 2007

By M Ujihira, M Komazaki, K Higuchi, D F

A diesel engine with a misfiring cylinder is likely to break down in a short time when the engine is used without maintenance. The authors have developed a method of detecting the occurrence of cylinder misfiring and specifying the misfiring cylinder by using wavelet analysis and statistical analysis on the root mean square (r.m.s.) values of two kinds of acceleration waveforms. This detection method is considered superior to traditional methods, which require several accelerometers, especially in terms of simplicity. Since the development of the method, research has been conducted on semi-automatic processing of measured signals and signal transmission from the worksite to a remote office. Field tests confirmed that 1 + 105 points of dynamic data could be transmitted through the mobile multimedia network within 15 minutes, and the time for signal processing was within 15 minutes. Final determination on the condition of a diesel engine in heavy machinery could be achieved within 30 minutes. Shortened processing time is expected by improvement of the processing software.

Jan 1, 2003

The Drake-Rivertree area lies in the far north east of the New England district of New South Wales. Drake is some 500 miles north of Sydney by road and 36 miles west of Lismore. Rivertree is situated 24 miles north of Drake.The Drake deposits were first worked in 1878 for gold which occurred in a very fine state in ferruginous gossan but at depth copper ore became more significant. The lodes at Rivertree, discovered in 1887, were worked for silver but mixed sulphides became more prominent in deeper levels.Several mines operated at each centre and each locality smelted its own ore.The mines at both centres were operated sporadically for many years though production was not particularly substantial.A number of the larger mining companies have shown a recent interest in this mining field with special emphasis on the Drake locality.GENERAL GEOLOGYThe two mining centres are situated to the north and south respectively of a belt of Permian marine sediments and volcanics similar to, and probably representing an easterly extension of, the rocks of the Emmaville district further west.E. C. Andrews (1907) recognized two stratigraphic units within what he called the Drake Series. The Lower Division consists of rhyolite flows, tuft's, breccias and agglomerates, followed by trachytic and andesitic tuft's containing cladochonns, thanmopora willcinsoni and other Permian forms.

Jan 1, 1962

Warkworth Mining has been successfully operating a large open cut coal mining operation in the Hunter Valley of NSW since 1981.The mine is a complexmulti seam operation and utalises both truck and shovel and draglinetechniques. Warkworth Coal Sales Ltd markets approximately 10 different coal types.Since the mines inceptionthe development of mine scheduling and planning has been an ongoing programme. Resource recovery and coal utalisation have been the driving factors with this development as we strive to achieve maximum revenue for the investment dollar.The principal aim of this paper is to discuss the scheduling methodology as it is utilised todayhighlighting the interaction in the development of the final coal products schedule.Whilst the system is notperfect it has evolved and operated successfully in these difficult economic times and offers a practical and achievable approach to resource optimisation.

Jan 1, 1992

The reality is that in today's world almost half of nearly six billion people on the planet do not have access to commercial energy and the services it brings. Based on UN projections, in 30 years time there are likely to be nearly three billion more people in the world, over 90 per cent of them in countries which are already economically poor. The World Energy Council (WEC), through its 102 member countries, monitors trends and developments and projects future trends. WEC is a non-governmental international body representing all forms of energy and is committed to the sustainable use of energy for all mankind. This paper is based on WEC studies and papers presented at its many conferences and congresses worldwide. Primary energy demand growth is dominated by the developing countries over the next 30 years. The world energy mix is projected to change very little over the next 30 years. Fossil fuel supplies (ie coal, oil and gas) are likely to decline from 77 per cent to 73 per cent, nuclear energy may grow from five per cent to six per cent and renewable energy sources (eg hydro, solar, geothermal, wind, tidal and biomass) could increase from 18 per cent to 21 per cent. World energy consumption is expected to grow by over 50 per cent over the next 30 years. The paper reviews changes in energy demand in the world, particularly in the Asia/Pacific region. Environmental issues are covered, as are developments such as solar energy from space and the status of renewable energy forms. Agendas for action to achieve change are also reviewed.

Jan 1, 1997

Mining regulatory authorities worldwide mandate frequent inspection of winder ropes used in shaft-equipped underground mines and ski lifts. Visual inspections are effective in identifying and assessing the type and severity of damage found in the exterior of the rope. In addition, electromagnetic or permanent magnet-based methods are used to identify broken wires, corrosion damage and other anomalies that occur anywhere within the core of wire ropes made of steel, which is a ferromagnetic material. The magnetic methods yield the loss of metallic area due to wire breaks and other damage in the ropeÆs section as well as local flaws that give rise to discontinuities in the magnetic field. The quantitative measurement of the loss of metallic area is indirectly related to the loss of breaking strength that is commonly used as a rope discard criterion. The ropes used in a mine winder in the Goldfields of Western Australia are inspected using Meraster 120B permanent magnet-based rope tester and their condition is assessed against published discard criteria.

Jan 1, 2003

By Tuite M. J, Woolcock L. J

The Awak Mas gold project is located in the Province of South Sulawesi, Republic of Indonesia. It is situated 300 km by road north of the provincial capital of Ujung Pandang. The capital is readily accessible by air from Australia via Denpasar on Bali or the Indonesian capital, Jakarta (Figure 1). Elevations at Awak Mas range from 850 to 1400 metres above sea level in reasonably rugged terrain. The area is covered by primary and secondary (regrowth) rain forest. The region is subject to an equatorial-type tropical climate. The annual rainfall is a high 3000 mm most of which falls in the rainy season between March and June. In the lower valleys rice, cloves and chocolate crops are cultivated. Title to the project area is secured by a Contract of Work (COW) issued to PT Masmindo Eka Sakti (MES) on 23 October 1987 by the Government of Indonesia. MES was controlled at the time by New Hope Industries group of Brisbane. After New Hope had completed initial reconnaissance exploration of the area, Battle Mountain Gold Company (BMGC) farmed-in in 1991 and earned a 60 per cent beneficial interest in MES.

Jan 1, 1996

Access roads for haulage, construction or maintenance purposes are discussed with particular attention being given to the un- sealed "all weather" form of construction for Off-Highway applications. The service conditions experienced by the surfaces used in these roads is examined. These conditions are discussed in terms of the conventional engineering properties used for natural gravel material selection. Experience gained during the construction of a pipeline access track is used to illustratE material selection guidelines based on geological input and an understanding of good construction practices. TMITDnIll IrTT Ohl In many Australian situations off-highway haulage by wheel or track supported vehicles is carried on unsealed, gravel roads. Although the unsealed gravel road is the back-bone of the rural road network in Australia, in general, traffic loadings are relatively low compared to the off-highway unsealed haulage road. The cost of the haulage/access road construction component is one important factor in project planning which needs careful consideration. It is no longer acceptable that the initial rough exploration track be gradually upgraded so that it will eventually carry construction and maintenance traffic safely and efficiently. Fatal accidents and

Jan 1, 1982

By M Ewart

The securing of a reliable water supply for a prospective mine in the North West Queensland Mineral Province is usually one of the most influential factors in determining the mine's feasibility. The Ernest Henry Mine required a reliable water supply to serve a demand estimated at feasibility stage to be up to 20 ML/day. Numerous options were considered before a decision was made to construct a 113 km long pipeline from Lake Julius as this was the most cost effective, reliable source of supply. The North West Queensland Water Pipeline is a multi-user, Queensland government funded project initially supplying up to 7000 ML/year of water from Lake Julius to Ernest Henry Mine, with provision made for expansion to serve future users in the region. This paper discusses the history of the pipelineÆs development, together with a summary of the scheme's design features. Environmental and licensing requirements, construction and operational issues are also discussed.

Jan 1, 1998

The Bendigo goldfield is centred on the urban area of Bendigo (population approximately 60 000) in central Victoria, 130 km north west of Melbourne, Australia. Gold was discovered at Bendigo in 1851 and production continued through to 1954. The Bendigo goldfield is the second largest goldfield in total gold produced in Australia, after KalgoorlieÆs Golden Mile with a total production of 22 million oz. The geology of the Bendigo Field consists of a series of tightly folded, interbedded sandstone and shale sediments. Within the sediments the gold mineralisation is hosted in quartz reefs or ribbons closely associated with anticline axes and reverse faulting. The gold within the quartz reefs is typically both coarse grained and erratically distributed.

Jan 1, 2002

By M Donatelli, E Grazio, A Heissenberger

The distribution of a contaminant in a bulk mass greatly influences the effectiveness of sampling procedures. Most currently used sampling guidelines for genetically modified organisms (GMO) testing have stringent distribution requirements. Specifically, all these protocols are based upon the assumption that GM material, if present, is randomly distributed. Yet, assuming randomness is risky because the applied sampling plan may not provide an accurate estimate of the content of the contaminant. Despite the general consensus that an evaluation of the possibility of non-random distribution of GM materials within lots is a pre-requisite for the definition of effective sampling protocols, no experimental data on the distribution of GMOs in kernel lots are available anywhere in the world. Additionally, to date there is no distribution-free statistical model to estimate sampling errors, thus making the theoretical definition of optimal sampling technique impossible when randomness cannot be assumed. Here we present preliminary results of the KeLDA project, which is the first study investigating the distribution of GM materials in large soybean lots imported within the European Union. The extensive variability of GM content, observable both within and among soybean lots, indicates that heterogeneity issues cannot be overlooked when defining sampling strategies for large lots of particulate material and that randomness cannot be assumed a priori. A new statistical model free from any distribution assumptions, developed in order to estimate the sampling error associated with different sampling protocols together with the risk of false-negative results, is also presented. The new model, which is applicable to any consignment of particulate material with respect to any kind of contamination, presents two novelties: first, freedom from any distribution assumption; second, the possibility of estimating the magnitude of the sampling error associated with different sampling protocols as a function of specific distributional properties.

Jan 1, 2005