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Multi Torque Industries and Jadefoil have developed a safer, more efficient method of explosive protection, retention, placement, and constraint. In particular, this refers to advancements in airbag technology, where the system will offer an alternative to conventional gasbags and decking methods to provide a far more controlled and safer working environment. Airbags have provided operator control and reliability which has not until now been possible in this type of application. The benefits have been noted by current users and the advantages have provided an increase in productivity and significant savings in explosive waste. Obvious problems with gasbags lie in their instability in hot conditions where the danger is associated with gas canisters exploding with great force posing a significant risk to operators. Other problems associated with the decking systems currently on offer is the lack of versatility and operator control. The airbag systems give the operator full control to guarantee accurate placement, assured retention whilst boasting a quick operation of less than a few seconds for conventional void blocking, decking and plugging. One of the main advantages of the airbags is that the operator has full control over placement and retention force, therefore in wetter conditions where slippage can be a problem extra air can be added at the operatorÆs discretion to ensure a sufficient grip. Technical calculations coupled with experimental testing have demonstrated that an airbag will support the weight of a 30 m water column in an 89 mm hole at an initial bag pressure of 5 psig. Applications are increasingly growing whilst more customers embrace their use. Advancements such as the ability to deck in overhead holes, block voids in overhead holes at any depth, explosive retention in very wet conditions, longhole stabilisers to prevent hole closure and concertinaed liners reflect a dynamic potential for new technologies. All of these applications provide a decrease in explosive waste, an increase in operator safety, an increase in explosive protection, and an increase in productivity.

Jan 1, 2004

The central thickened discharge system of tailings disposal takes advantage of the natural beach slope formed by sub-aerially discharged tailings, and the non-segregating properties of thickened tailings, to create a homogeneous conical stack. The need for containing embankments can be largely avoided leading to capital and operating cost savings. Methods for estimating beach slopes and tailings density, essential parameters for the design of such a system, are described. Case histories from three mining operations are used to illustrate the application of the technique, There are also seen to be potential advantages in the areas of water management, seepage, and rehabilitation. Laboratory and in-situ testing enable parameters to be determined.

Jan 1, 1991

Despite the research interest on non-cyanide gold lixiviants over the past three decades all the non-cyanide gold processes are still at the developmental stages with limited understanding on solution and pulp chemistry in some cases. This is partly associated with:the difficulties in measuring reliable equilibrium data for various gold(I/III) complexes with non-cyanide ligands; the lack of knowledge on mixed-ligand complexes; and different kinetic stabilities of gold(I) complexes with respect to disproportionation. This paper presents reliable equilibrium data for complex formation, dissolution, precipitation, hydrolysis and disproportionation reactions of gold(I/III) compounds with a range of non-cyanide ligands: S2-, HS-, S2O32-, SO32-, SCN-, SC(NH2)2, OH-, NH3, Cl-. Solubility of gold(III) compounds with non-cyanide ligands follows the order: Cl- > NH3 > OH-. In the case of gold metal the solubility order at a given temperature is MgS > Fe(III) or Cu(II) / Cl- > Cu(II)/NH3 > NaOH, but the solubility increases with increasing temperature. Rate of gold oxidation with different non-cyanide lixiviants depends on the oxidant, ligand and temperature and follows the general order of oxidants: Fe(III) or Cu(II) > X2 or OX- > O2 (X = halogen). In the case of metal ion oxidants oxygen is required to reoxidise Cu(I) or Fe(II). Some of the reported data on chloride and thiosulfate leaching of gold are presented to highlight the effect of additives and the copper, silver and sulfur contents of the starting material on the success of non-cyanide leaching processes.

Jan 1, 2004

In June 1992, the High Court of Australia recognised native title of the Meriam people over parts of the Mer Island in the Torres Strait as a form of common law. The Court also indicated that native title may have survived European settlement of the mainland Australia where it had not been extinguished by Governments and Aboriginal people have maintained their traditional connection with the land. The decision meant that two systems of land law were seen as existing side by side in Australia: ò one which derived from grants from the Crown under laws passed by Parliament; ò another which derived from the diverse laws and customs of the many Aboriginal groups in Australia.

Jan 1, 1996

By Johns A. L

The concept of the Melbourne Underground Rail Loop and the organ- isation to achieve its construction are covered in the companion papers (Reference 1, 2) and will not be repeated here. The Victorian Railways, as well as being the eventual operator of the Loop when it is completed by MURLA, have also been responsible as "Contractors" to MURLA for the construction of the "cut and cover" or "box" tunnels and related approach works located on existing Railway property. These tunnel connections link the existing suburban system to the new underground works. The following tabulation indicates the significant work volume involved in this cut and cover tunnelling exercise and which is covered in some detail by this paper.

Jan 1, 1981

By J van Niekerk

The BIOX« process for the treatment of refractory gold ores and concentrates has been commercially in operation for 18 years. A total of six BIOX« operations have been successfully commissioned since the commercialisation of the process. Four of these BIOX« plants are still in operation today. There has been a renewed interest in the process the past few years with two BIOX« plants, the Suzdal plant in Kazakhstan and the Fosterville plant in Australia, scheduled for commissioning during 2004. Four new projects are also in various stages of development and are currently scheduled to be commissioned during 2005 and 2006. Research into the process are currently focussed on the two highest operating cost items for the commercial operations, namely power for agitation and air dispersion and cyanide consumption during leaching. Laboratory aeration and agitation testwork using the A340 up-pumping agitation system has shown that similar mass transfer rates can be achieved at slightly higher agitator power. The up-pumping system, however, eliminates the need for a separate blower and sparger system as air is introduced into the slurry from the slurry surface. The use of the thermophile bacteria as the final oxidation step during biooxidation has shown great promise. Reductions in cyanide consumption of up to 50 per cent were achieved when using the combination mesophile and thermophile process compared to standard BIOX« product solids. The combined process takes advantage of the milder oxidising conditions of the well known BIOX« process for the bulk of the oxidation and then uses the high temperature thermophile bacteria to complete the oxidation. The ASTERÖ process for the biological degradation of cyanide and thiocyanate containing effluent solutions has been proven to be efficient and stable. The process uses an activated sludge system with a residence time of approximately six hours in the sludge reactor. Heavy metals and metal cyanide species have also been shown to be removed successfully from solution.

Jan 1, 2004

Mining is a high risk, high capital and potentially high reward undertaking. A large proportion of the risk comes from a lack of definition of the orebody (which also provides some of the potential) and the unpredictable nature of the market. This makes the planning process difficult but encourages the development of a robust yet flexible mining system. The system should be capable of absorbing some deviation from the anticipated concept without a significant impact on profitability. The mine planning process tends to consist of a series of related but discrete stages. For instance, the pit shells are designed, a schedule for the pit shells is created, a plant fleet is chosen to achieve the schedule and a financial analysis is carried out on that scenario. It is likely a few iterations are carried out using various mill throughputs to produce a favoured financial result. The problem is that handing results from stage æBÆ for use in æCÆ doesnÆt encourage a flexible system. æCÆ is likely to be built for exactly æBÆ. Unfortunately, in mining, æAÆ (the orebody) has the highest potential for variability and impacts everything else downstream. æDÆ the market also has high potential for unplanned variability. These variations can spread and æreverberateÆ through the whole mine process. For example an unexpected increase in ore oversize impacts all downstream mine processes to the primary crusher which may in turn create problems back æupstreamÆ by restricting throughput rate. Also an unexpected drop in demand or price could require modifications to the planned production rates. This paper looks at how mining process simulation can be used to support the development of strategies to counteract unforseen circumstances or alter production to match fluctuations in demand and price.

Jan 1, 2003

By Coppock BW

Sintering of lead and zinc concentrates is practised by Sulphide Corporation Pty. Limited to provide both desuiphurised lump sinter feed, for simultaneous reduction to zinc and lead in the Imperial Smelting Process blast furnace, and sulphur dioxide gas for sulphuric acid manufacture. From November, 1969 a 20 percent increase in production rate has been obtained through improvements in operating technique. A gradual increase in bed permeability was achieved by modifications to the feed mix conditioning equipment and by improving moisture control. However advantage could not be taken of the higher permeability to increase sulphur elimination because the hardness of the lump sinter decreased. Higher throughput, better quality sinter and more stable sintering conditions were however made possible by simultaneously: 1. reducing segregation and compaction in the sinter bed, by narrowing the discharge opening of the main layer feed hopper, 2. reducing the sizing of sinter returns to give a closer size spectrum of particles in the feed mix, and 3. increasing the sulphide sulphur content of the feed mix to give higher bed Temperatures.

Jan 1, 1972

Although a formal EES was not prepared for the WIM project due it winding down, CRA Ltd has been through the EES and planning scheme amendment process for its demonstration plant. Community consultation was involved with all aspects of this process. The paper outlines the WIM EES consultation program and provides lessons for future community consultation for major projects in regional locations with significant potential to alter the environment.

Jan 1, 1992

By Sullivan T. D, Lohe E. M

Geological structure is one of the main controls on ground conditions within mining. It has a significant impact on the mining conditions and productivity of coal mines within the Sydney - Bowen Basin. The three main types of faults common to this region, normal, reverse and strike-slip systems, each present distinct challenges to mining. These systems effect a wide range of geotechnical and mining conditions within the mines. These include coal quality, strata stability, goat and caving behaviour, productivity and maintenance schedules of mining equipment, mine design and mine-site stress fields. A better understanding of the regional, local and mine-scale structural setting, timing relationships of structural events and the mechanisms of fault formation will greatly aid industry's push for greater productivity and competitiveness.

Jan 1, 1991

By B Roach, P M. Ashley, B Hooper

Mineral occurrences of the Hillgrove Au-Sb-W district are hosted in late Palaeozoic polydeformed, hornfelsed metasediments and Permo-Carboniferous granitoids of the NewEngland Orogen. In excess of 204 individual occurrences have been identified to date with the mineralisation developed as strike extensive (>20 km of known veining) and potentially depth extensive steeply dipping fissures. These are contained within an elongate area measuring some 9 km by 6 km in surface dimensions. Recorded gold production of 720 000 ounces along with current resources in the order of 340 000 ounces highlight the significance of this district. Historical antimony production is estimated at in excess of 50 000 metric tonnes. Significant tungsten of over 2000 t in the form of scheelite has also been produced from the field. Mineralisation is developed in veins, vein breccias, sheeted veins, network stockworks and as alteration sulfide haloes to the main structures. The vast majority of fissures are subvertical and vary in widths of up to 20 m in places. Paragenetic studies have previously indicated that the earliest mineralising event was a scheelite-bearing phase of quartz veining. Subsequent phases of arsenopyrite-pyrite-quartz-carbonate veining were accompanied by gold and minor base metal sulfides. Alteration is typically sericite-ankerite-quartz. Overprinting stibnite-quartz veining with gold-electrum, aurostibite and arsenopyrite form an important subsequent phase. Veining can be inferred from historical records to extend for vertical depths of over 1 km.

Jan 1, 2004

A nuclear technique utilising the gamma-ray resonance scattering process is used at Isa Mine for the determination of copper in drill core and bulk mineral samples. The Copper Bulk Analyser (CBA) provides quick and accurate non-destructive copper analysis of drill core at costs two to three times cheaper than conventional chemical techniques.The almost immediate availability of sample results enhances the efficiency of the mine geologist in the duties of grade control, design of diamond drilling programmes, and input to planning. The unit has proven to be a reliable and accurate production tool requiring a minimum of technical support.

Jan 1, 1990

By E V. Man, O N. Savassi, J-P Franzidis

In flotation, the property that is exploited to effect the separation of a mineral from an ore is referred to as its floatability. Assessment and quantification of ore floatability is of fundamental importance in modelling and simulation of flotation circuits. This paper describes the design, construction and operation of a new laboratory flotation rig that has been developed at the Julius Kruttschnitt Mineral Research Centre (JKMRC) to determine the floatability of different ores on a small-sale. The rig is designed for continuous operation. The major features of the rig are highlighted in this paper. An unique characteristic of the rig is a 9.1 L conditioning vessel. This provides a mixing regime close to plug-flow which avoids complications such as different collector coverages for similarly sized particles (which would considerably increase the complexity of ore floatability determination). The main advantages of this rig when compared to conventional batch flotation cells include better control of the chemical environment and the ability to determine froth recovery, entrainment and water recovery with increased accuracy. Preliminary tests undertaken with a high-grade lead/zinc ore from BHP Cannington are presented demonstrating the good level of reproducibility obtainable in operating the equipment.

Jan 1, 2000

By E Werner, B R. Leavitt

The chemistry of acidic mine drainage discharging from flooded coal mines is commonly reported to improve with time after flooding. This investigation describes a 18-year dataset of post-flooding water chemistry for a below-drainage underground coal mine within the northern Pittsburgh coal basin (Pennsylvania, USA). The Montour mine is a 5650-hectare below-drainage coal mine of maximum 260 metres depth. Montour was closed in 1980 and flooded to within 38 metres of land surface within 4.8 years. Pumping averaging 210 L/s was then employed to maintain water levels at this elevation. The flooded proportion of the mine (by volume) at full flooding was 56 per cent. The shaft where water was pumped from Montour for water control is located about 70 per cent of the distance between the mine water table and the back of the mine ù that is, it is close to the back of the mine. The residence time (total water volume at flooding divided by pumping rate for control) is estimated at 5.6 years. Time series of chemical analyses show three phases of chemical behavior in post-flooding discharge. In Phase I (zero to two years after flooding), iron concentrations were high and reached their maximum (1100 mg/L). In Phase II (two to four years after flooding), a transition was begun to alkaline conditions, with decline in iron and other solutes. In Phase III (>4 years), net alkaline conditions began, with iron concentrations declining exponentially to 50 per cent of mined volume. This attainment of net alkalinity in this case may have also depended on abundant calcite in overburden extended up to 30 m above the mine floor.

Jan 1, 2003

This study introduces a new probabilistic approach to seismic stability analysis of embankments and slopes. The approach is based on Sarma's solution, which is modified through presentation of the seismic force by its horizontal and vertical components; i.e. the force may have an arbitrary inclination. The probabilistic modelling includes Monte Carlo simulation of the shear strength parameters of the soil mass, which are assumed to have a normal distribution. The probability of failure is determined based on the seismic co-efficient, which is treated as a random quantity. The probabilistic approach is illustrated through a solution of a numerical example from an opencast coal Mine.

Jan 1, 1992

By Watson K, Pollard D. M

The electrolytic recovery of metals from solution requires an understanding of the characteristics of the particular system employed, and the current efficiency and morphology of the deposit are influenced by such factors as cell design, metal ion and supporting ion concentration, acid concentration, temperature, impurity levels and cell design. The electrolytic deposition of both cadmium and silver present individual difficulties, and special cell designs are used for each of these metals. It was found that cadmium deposition was plate-like at lower cadmium concentrations, and at higher current densities. The presence of zinc in the electrolyte promoted nodular growth. Current efficiency remained high even at 50C in contrast to published information. Silver deposition morphology was relatively unaffected by changes in silver concentration, pH and current density. Current efficiency was reduced as temperature was increased.

Jan 1, 1989

Large Off Highway Trucks operated in this country are generally of Diesel Electric Drive, this system tends to employ the familiar Electric Wheel. A number of fleets now employ the Traction Motor System as an alternative. An investigation is made of the operation of two such fleets. A brief description is given defining the components and their basic functions in each system. Available life history is presented and system reliability, maintainability and operator reaction is examined. Trlmnnnr rpm rn~r In the past large Off Highway Trucks operated in this country, that is those greater than say 120 tons, have tended to be driven by a Diesel Electric traction system. Although manufacturers are now offering mechanical or mechanical/hydraulic drives in the larger machines comments will be restricted to examining the Diesel Electric System. Since commencing operations in the mid 1960 period Hamersley Iron has made use of the diesel electric drive system using the familiar Electric Wheel. A departure was made at Tom Price with the purchase of the Wabco 3200 Series Trucks. These 235 ton capacity units employed a dual rear axle system with externally mounted motors. In 1976 a

Jan 1, 1982

THERE are few industrial and metallurgieal processes which do not require the application of heat energy, and the modern demand for increased working efficiency has resulted in attention being paid to temperature control as a means of ensuring fuel economy and more efficient plant operation. In general, mill accuracy required is not very contant in laboratory work, and few industrial operations are controlled to within less than 5° while in many cases greater limits are allowable. Almost every thermal property of matter has been suggested as a basis for the construction of pyrometers, but the thermo-electric type finds by far the widest application, and hence this paper will deal only with the principles, construction, and uses of this type of instrument. THERMOELECTRIC PYROMETRY.In the year 1821 Seebeek discovered that if the ends of two dissimilar metal wires were joined and one junction heated, a current flowed in the circuit, and the KMF (electro-motion force) set up could be measured by inserting a galvanometer at the cold junction. The phenomenon was not thoroughly investigated for many years, but, as the demand for high-temperature thermometers increased, several investigators, of whom Le Chatelier was one of the pioneers, successfully endeavoured to utilize the principle in pnometric construction. The couples which gave the most satisfactory results were discovered, improvements were made in material and design and the present-day type of instrument gradually evolved. The apparatus consists of three main parts, viz. (1) The thermo-couple itself of two dissimilar metal or alloy wires together at one end. (2) The leads which connect the terminal of the thermo-couple with the measuring instrument.

Jan 1, 1923

The New Zealand Mines Rescue Brigade was established as a result of the Dobson mine disaster on 3rd December 1926, when 9 men lost their lives. Prior to this, there had been four major disasters in New Zealand coalmines, with a total of 145 fatalities. Only large-scale events such as explosions or major fires were considered reportable. Until and including the Dobson disaster, no mine emergency response facilities or organisation was in place.   Unfortunately, over the next five decades the establishment of a Mines Rescue Service did not mean that disasters involving multiple fatalities ceased. The coal mining industry continued to suffer the consequences of poor mining practice, inadequate or inappropriate monitoring and management, and sometimes complete disregard for the regulatory requirements current at the time.   The role of Mines Rescue has been defined in statute, and regulated by Coal Mines (Mine Management and Safety) Regulations. Currently, the statutory obligations have been under the Mines Rescue Trust Act 1992.   The Mines Rescue Brigade historically, has primarily been a reactive service, with stations and facilities established to train brigadesmen in emergency response procedures, specifically to mobilise in the event of a call-out at any one of the many coalmines operating within each stationÆs area of jurisdiction.   Over the last ten years, this role has changed. The service has adopted a proactive approach to emergency response, and has established a close liaison with all mining and tunnelling operations throughout industry, both underground and surface. The objectives have become emergency prevention focussed, and the service has incorporated a range of theoretical and practical training, simulated exercises, more sophisticated equipment and techniques, and a desire to ensure that emergency response capabilities are not needed, whilst maintaining the traditional and statutory obligation to respond if they are needed.

Jan 1, 2004

By Smith E. L

The Ore Reserve/Exploration System implemented at Mount Isa for M.I.M. Holdings Limited is a comprehensive computer system designed to process assay, geological, structural and survey data input via special purpose logging sheets from daily activities at Isa Mine, Hilton Mine and various Carpentaria Exploration Company prospects. The system performs two basic functions; (1) data acquisition, validation and file maintenance to prepare the data for retrieval, and (2) generation of routine and optional reports. The types of reports available range from masterfile detail printouts and retrieval of data by key items to survey computations, structural analyses, cutoff calculations, statistical analyses and ore reserve calculations by the polygonal, inverse square or moving average techniques. The use of various optional reports available through the system is illustrated by several examples, and planned future development is discussed.

Jan 1, 1973