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By W Lu, D Wang

Study of coal oxidation at low temperatures forms the basis of investigating the inherent properties of spontaneous combustion of coal. In general, the process of coal oxidation at low temperatures is very complex, involving many factors. Experiments examining the properties of oxidation and ignition of coal have been carried out. Based upon the results of these experiments, the catastrophe properties in the process of coal oxidation are analysed and the mechanism of catastrophe is proved for the ignition of coal. A folding catastrophe model is also established for the process of coal oxidation. Results obtained show that the process of coal oxidation to ignition is discontinuous, where the coal-environment system yields structure destabilisation. The system can jump from one stable attractor to another. The research results presented in this paper help to show the irregularities of coal oxidation at low temperatures and how to pursue effective control measures.

Jan 1, 2005

A cry that is often heard from front-line employees, particularly as a mine grows or circumstances change is "We used to be one big team but now they have set up teams for different functions - we don't know what's going on and we don't share resources any more. We used to just get in and do what had to be done, now we can't.". It usually occurs after management decides that, with the increasing mine complexity, functions and accountabilities of a manageable size need to be identified and defined for individuals and teams to facilitate optimum performance. However, as the statement indicates, these changes have often not delivered all the intended benefits. This paper will explore the reasons why the full benefits have not been realised and will identify actions which can be taken to improve the likelihood of optimal outcomes.

Jan 1, 1998

As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

The correct assessment and understanding of geotechnical conditions is fundamental to mine design and, hence, successful (safe and efficient) mine planning, design and operations. However, this assessment and understanding is simply not possible unless there is a sound appreciation of the geology of the project. This paper addresses geological uncertainty in mine engineering and its communication, and shows that a mining project that does not take geology properly into account in the engineering phase is fraught. Uncertainty levels become excessive, which leads to hazards and consequential risks in design and operations in terms of both safety and efficiency. Several examples, both positive and negative, are provided to make the point. The paper concludes that mining geologists must become more overtly cognisant of the influence of geology on mine engineering. Equally importantly, mining (and geotechnical) engineers must communicate better with their geological colleagues to ensure that they (the engineers) have a clear understating of the geological issues affecting their operations. The engineers must know how to ask the right questions of the geologists. Engineers who do not understand and take account of geology in their designs and operations are failing the expectations of stakeholders.

Jan 1, 2006

By Z B. Rakisheva

By explosion rock mass behaviour is conditioned by preset complex of rocks natural characteristics. Very important role of blockness, which is percent (share) content at examining massif of natural separatenesses of different dimensions and configurations, separated each from other by the cracks of geological and technogene origin. Besides natural properties of massif the power, detonational characteristics of applied explosives, parameters of explosives charges disposition at massif and technology of explosion influence vastly at lumpiness (granulometric structure) of exploded rocks. The mathematical model of rock mass destruction by explosion had been elaborated and substantiated. It ties mutually the initial data (rocks properties, parameters of the charges disposition) and final results of explosion (granulometric structure of exploded rocks). The program of this complicated problem solving had been compiled. Analysing the received results of the problem solving, one can reveal contribution of each group of influence factors for lumpiness of exploded rocks. This fact creates preconditions for elimination or diminution of negative role of some controlled initial data.

Jan 1, 2003

By B J. Fallon

This study used structural equation modelling (SEM) to develop a series of models to explain the impact of work-life balance on employeesÆ perceptions of job performance, job satisfaction, turnover intentions and absenteeism. The sample comprised 257 participants (108 males and 149 females) from a range of occupations and levels of seniority. In sum, the results clearly demonstrated that successful work-life balance is associated with higher levels of job performance and worker satisfaction and with decreased levels of absenteeism and turnover intentions. The data also lent support to the impact of employeesÆ coping styles, schedule flexibility and supervisor support on employeesÆ abilities to balance work and life. It is concluded that tangible benefits to an employerÆs bottom-line can be anticipated from organisational initiatives to assist employees to better balance their work and personal lives.

Jan 1, 2005

There is an established need for an inflow of foreign capital if New Zealand is to meet projected growth rates. The Government recognises this and encourages capital inflows especially where there are allied economic benefits such as the access to specialised know-how or export markets. The Government has promulgated certain Regulations which are administered by the Reserve Bank. Under the Capital Issues (Overseas) Regulations 1965, consent is required before any company incorporated overseas can commence business in New Zealand or before an overseas person can borrow or raise any money in New Zealand. A New Zealand company is deemed to be an overseas person if more than 25% of the voting power is held by non-residents. In terms of current policy, overseas companies are permitted to borrow in New Zealand only a limited amount of working capital and some longer term capital calculated on the ratio that their New Zealand owned equity capital bears to their overseas owned equity capital. Wholly owned overseas companies are expected to bring all of their Fixed term capital from overseas.

Jan 1, 1971

Differences in the assay results of replicate samples engender doubts on the reliability of ore sampling and of assaying procedures. An analysis of variance is a technique to estimate the variability at each level of the procedures. In an example, the variability of one-metre core samples was far greater than that of the assaying technique.

Jan 1, 1976

The mineral sands industry in Australia can contribute much more sig- nificantly to economic development beyond the year 2000 by increased production of constituent minerals such as ilmenite, zircon, rutile, leu- coxene and monazite from existing and new resources, and especially from downstream processing to intermediate and finished products based on these resources. The end-use areas for mineral sand-based products include those products whose demand is tied to general economic growth, such as paints and plastics, and refractory bricks for the steel industry. High techno- logy applications such as zirconia ceramics and super-magnets are indica- tive of new developments in technology which provide considerable scope for expansion at higher rates than overall western world economic growth. An optimistic outlook for the industry is outlined, based upon a brief review of opportunities.

Jan 1, 1988

Uniaxial compressive strength and Young's modulus values measured in the laboratory on NX diamond drill cores were examined statistically to bring out any significant differences between different locations in the mine which might require special treatment in subsequent photoelastic analyses of the mine layout. Correlations were sought between the strength and modulus and various other features of the rock. The estimated mineral content of the core correlated with the modulus of the core, but the range of modulus values was too limited to show any strong correlation with compressive strength.Strength in the vertical direction was found to be significantly higher than in the horizontal direction and the same pattern was followed by the moduli, but was less pronounced. It was concluded that, whilst the modulus variations were significant, they would not invalidate any photoelastic studies.

Jan 1, 1969

By Houghton BF

Ruapehu is an extremely active andesitic composite volcano, built in at least four cone- building episodes over the last 250 ka. The volcano was constructed by a variety of extrusive and subplinian, strombolian, phreatomagmatic and dome-related explosive eruptions from summit, flank, and satellite vents. The volcano may be subdivided into the cone itself, of volume 110 km3, and a surround- ing epiclastic ring plain of similar size. Four facies associations can be recognised at Ruapehu,-two each on the cone and on the ring plain. Neither cone nor ring plain provides a complete record of the history of the volcano. The cone is dominated by the products of extrusive eruption, as primary pyroclastic deposits are seldom preserved, being rapidly removed by erosion from the steep water- saturated and/or snow-covered flanks of the cone. The ring plain consists of the products of mostly explosive activity forming an alter- nation of primary pyroclastic fall deposits and material transported from the cone by lahars, floods and debris avalanches and then rapidly reworked in sediment-choked hyperconcentrated Streams.

Jan 1, 1987

As this Seminar is on "Progress - Mining and the Environment", I am taking the liberty of extending my address beyond the scope implied by the subject, "Rehabilitation of Mined Land", with a preliminary discussion on broader economic issues relevant to "Progress and Mining in Western Australia" before discussing its effect on the Environments Western Australia is nearly one million square miles in area and has a population density of approzimately one person per square mile. Because of its vastness it has wider climatic variations than any other Australian State. The north is tropical and the south is in the temperate zone. The major portion of the State is an arid plateau with less than 10 inches of mean annual rainfall. The climate, rainfall and soil conditions of the South-West region are more favourable to agriculture than any other part of the State and consequently was settled first. The immediate need of the colonists being food and shelter, the early economy was based on farming and forest products.

Jan 1, 1971

This brief overview of the history of Brown Coal mining in Victoria is a luncheon presentation -I do not intend to make it indigestible with extensive listings of resources or production. There is a vast pantry of collated historical records and of vari- ous predictive studies available for the enquired with a hearty digestion. A gourmet collation is provided in The Aus IMM Monograph No 11 published in 1984 entitled "Victoria's Brown Coal-A HUGE FORTUNE IN CHANCERY", currently still on offer by the Institute and available at a bargain price in the foyer at this conference. Monograph No 11 also provides a feast of excellent references on the theme of Victorian Brown Coal assembled by the several contributors. In contrast, my presentation paper is a fast-food service, extracts from the printed paper only-you have no choice-you "get what you get" and in small quantity. I hope it will tantalise your appetite -like Oliver Twist you will ask for more. -Buy the Monograph!

Jan 1, 1989

Benchmarking of mining operations has been in vogue for a number of years: it seems teams are forever flying around the world to try to understand what other operations are doing. However, unless a benchmarking exercise involves data gathering at a fundamental level and a rigorous analysis process is applied, the trip will be nothing more than industrial tourism. When benchmarking is performed thoroughly, the range of comparisons that can be made is extensive and informative, and need not be restricted to sites with similar conditions and equipment fleets. This paper describes the detailed and rigorous process for benchmarking used throughout AMC benchmarking studies. The paper demonstrates how, through drilling down to the underlying drivers, the often heard cry of æyou canÆt compare us, weÆre differentÆ can be overcome. Included in the discussion are a number of significant issues that have been identified during AMC benchmarking studies. The paper then considers the types of opportunities that have been identified and the potential for improvement. The paper concludes with a discussion of the implications for planning, measuring and management of operational performance.

Jan 1, 2003

By Quast K. B, Newell R, Caterford J. H

The most common reason for gold-bearing deposits being refractory is the presence of sulphides; in many cases these interfering minerals contain arsenic, antimony, or other environmentally-sensitive elements. A number of processes have been proposed or developed for pre-oxidation of interfering minerals. In most cases developers have focussed on gold recovery and capital costs, with relatively little data on the deportment or form of these potentially harmful elements. This paper surveys recent work connected with pressure pre-oxidation processes. Data from pilot plant treatment of refractory gold materials, using the nitric acid Redox process, is discussed along with the attendant flowsheet and engineering implications. Four refractory gold-bearing materials have also been tested at the University of South Australia for arsenic and antimony deportments.

Jan 1, 1991

By Silitonga M

Generally, the acceptable parameter for predicting the intensity of ground vibration due to a blast is the amount of explo ive u ed and the distance from the explo ion. A eries of closely controlled tests were carried out and it was observed that the degree of confinement or burden of an explosive charge play an important role in the variation of the transmitted magnitude of the shock wave through the ground.The intensity of the shock wave increases with burial depth or with greater confinement of an explosion until a critical depth is reached.Beyond this critical depth, the magnitude of ground vibration remain constant. This is an important finding, which explains the anomalies between the expected level and the monitored ground vibration in a particular situation.

Jan 1, 1984

Investigations into the flotation behaviour of single minerals, mineral mixtures and ores at the CSIRO Division of Mineral and Process Engineering have led to the development of sophisticated laboratory flotation testing equipment. Both routine and complicated flotation investigations can be conducted in a precise and reproducible manner using procedures and equipment that have been refined over many years of conducting careful batch flotation testwork. Several important advances in flotation research can be attributed to changes in testing procedure developed as a consequence of the availability of this equipment. The flotation cell and ancillary equipment is described and associated developments and techniques discussed.

Jan 1, 1992

This paper describes the planning mechanism and implementation of a progressive rehabilitation programme at Hunter Valley Mine in the Upper Hunter Valley of New South Wales. Hunter Valley Mine is a large open cut coal mine which produces approximately 7.0 million tonnes of coal (run of mine) annually for export. This production level involves the movement of some 60 million tonnes of waste and coal each year.The rehabilitation programme at Hunter Valley Mine has been developed to provide a combination of pasture, based on improved pasture species and timber belts to enhance the visual characteristics of the rehabilitated landform, whilst creating amenity in the form of shade for livestock.The operational philosophy for the rehabilitation programme is that of progressive rehabilitation. The best time to undertake rehabilitation is now.' As a result, planning for the rehabilitation programme is continuous, so that all site works are completed in time for vegetation establishment during the critical periods each year.

Jan 1, 1992

The results of iron ore exploration in Western Australia between '1961 and 1964 are outlined, with particular.reference to the Hamersley Iron Province. Exploration during: these three years has increased the known resources of the-,Statle from 275 million tons to almost 9,000 million tons of high- grade hematite ore. In addition, reserves of lower-grade .pisolitic limonite ore are-estimated to amount to 6,000 million tons. The origin and characteristics of the different types of ore is discussed,

Jan 1, 1964

By J M. Dwyer, S Williamson

Acceptable post-closure performance of decommissioned mining operations is a critical factor in persuading todayÆs environmentally conscious public that the mining industry will not continue to burden future generations with the legacy of environmental tragedies. Post-closure impacts must be identified and managed through robust engineering design if the post-closure environment is to be environmentally sustainable. To manage potential post-closure risks (environmental, health, safety, social and economic) within acceptable limits, WMC incorporates a risk-based approach to closure planning and engineering design. WMCÆs risk-based closure engineering design process provides a simple methodology for developing robust closure plans û the process æengineers outÆ unacceptable risks and æengineers inÆ a sustainable post-closure environment. Benefits of the risk-based process include stakeholder endorsed closure criteria for an agreed post-closure land-use, focusing of resources on major risks, and a realistic and accurate estimate of the required closure provision. The outcome is an increased likelihood of satisfying the three pillar goals of sustainable development û a financially sound solution that poses a low risk to the environment and future generations.

Jan 1, 2003