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It is argued that the capture of par- ticles by bubbles is primarily caused by hydrophobic ("structural") attraction forces. Neither dispersion forces nor double-layer forces can account for hydro- phobicity, though the latter are known to influence the kinetics of capture. The recent experiments of Israelachvili and Pashley (Nature, 300: 341-342, 1982) with hydrophobic mica plates provide the first measurements of the range and magni- tude of hydrophobic interaction forces.

Jan 1, 1984

By C Tukel

Copper sulfate is traditionally used to activate various types of sulfide minerals. The list of users includes Falconbridge Sudbury operations, where copper sulfate solution is added to the pyrrhotite/pentlandite middlings at the scavenging stage. Results from some batch tests reported in the literature suggested that copper activation is helpful for the improvement of pentlandite recovery, especially in the difficult to float fine particle range. Any improvement in pentlandite recovery is important since it is the main nickel bearing sulfide mineral. The impact of copper sulfate for this function has been investigated. Since the focus of current investigation was the flotation behaviour of minerals at the scavenger stage, rougher flotation was kept as constant as possible at two different weight recoveries, namely 13.2 per cent and 15.5 per cent that is relevant to industrial practice. Samples taken during batch testing were extracted using DETA and flotation products from selected tests were analysed to determine the recovery by size behaviour in relation to the use of copper sulfate. Results provide significant evidence that the addition of copper sulfate to these middlings does not yield greater nickel recovery, either on an overall or specific particle size basis. It is concluded that copper sulfate is wasted in the process and that self activation behaviour of the ore at a slightly reduced pH is sufficiently significant to maintain the scavenger recovery of pyrrhotite and pentlandite at desirable levels. Results obtained from limited circuit trials have shown supporting evidence for this conclusion.

Jan 1, 2005

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

By Thorburn D

This paper reviews the history of environmental assessment in New Zealand with reference to mineral developments. Emphasis is given to larger more controversial projects particularly metal mines. The changing role and application of the Environmental Protection and Enhancement Procedures is examined in the context of changes in the government's environmental administration and the response of the Ministry of Energy's resource allocation group. Conclusions are drawn on the effectiveness of the present environmental assessment activities and on the allocation of administration of priorities in the Ministry. The Ministry of Energy has effectively ceased to exist.

Jan 1, 1990

By Worotnicki G, Tillmann V. H

Past experience with fully bonded cable dowels placed as a means of reinforcement in highly stressed crop pillars at the New Broken Hill Consolidated Limited (NBHC) mine indicated such support was not fully effective. Typically overbreak of the crown occurred leaving long lengths of cables hanging from the back stripped of grout and rock with the potential load carrying capacity of the cables not having been fully utilised. This mode of behaviour had been observed in the cable dowelled crowns of three longhole open stopes (EROS) mined to the No. 12 level at NBHC. A system of support with improved mechanism of load transfer from rock to cable and capable of full utilisation of cable strength was proposed for the crown pillars of future Stopes.

Jan 1, 1983

By T QUINLAN

A resource estimate uses data obtained by sampling an orebody. An example is described in which a random drilling pattern did not provide a representative set of assays, and the estimated resource was significantly less than the mine production. It is believed that a better estimate would have been made if the exploration holes had been drilled on a regular grid.

Jan 1, 1992

By Jena P. K

Smaller deposits of high grade chalcopyrite or the concentrates of low grade and complex copper bearing ores, can be subjected to extraction processes other than smelting and converting. Low temperature chlorination and segregation processes are among those mentioned in the literature. In the present work, extraction of copper from a Brazilian chalcopyrite concentrate by slurry chlorination with chlorine gas at room temperature, dry chlorination by chlorine gas in the temperature range of 350 to 450¦C and segregation roasting of the calcined concentrate in the temperature range of 650 to 800¦C have been carried out. The effect of several experimental variables on the extraction of copper has been discussed in all these cases. Under optimum experimental conditions, 100 per cent Cu extraction was possible by either slurry or dry chlorination processes and around 86 per cent Cu by segregation roasting. For all the three cases, possible methods have been suggested to trial the studies on a pilot scale to assess their technoeconomic viability.

Jan 1, 1992

By Kennedy B. J

The 1100 Orebody is the main copper production area of Isa Mine with an output of 390 000 tonnes per four week period and a work force of approximately 260 men per shift. Currently a total of 56 nippers work a three shift, five day week roster to-service crews spread over a strike length of 1000 m and a vertical height of 220 in. A variety of rail and diesel equipment provides shaftto cribroom and cribroomto sublevel work place transport of men and materials. Overall eficiency and safety has been improved with a selected group performing supply, storage, clean-up and "bus runs" throughout the orebody - activities which are further co-ordinated by an FM radio system linking units with a control clerk.

Jan 1, 1977

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

Territory Iron has seen fit to revive the old Frances Creek iron ore mine some 30 years after it ceased operations in AustraliaÆs Northern Territory. The key to this revival has been the changes that have happened since market forces, infrastructure limitations and a cyclone combined to force its closure. As it breathes life into this old mine, the Company is serious about its responsibilities to its shareholders, to its workers, to local and regional communities and to the environment. This paper addresses how Territory Iron has approached technical, operational and regulatory issues that apply in Australia. Some insight may be gained into the myriad of tasks that mining companies face to revitalise an old mine. These tasks vary from employing the latest exploration tools, best practice drilling, sampling and modelling of orebodies, optimisation of pit designs and schedules, maximising product value by blending, optimising infrastructure usage and minimising capital and operating costs. All of this has to take cognisance of commercial, environmental and other issues including Native Title.

Jan 1, 2007

By M Simpson, K Brodie, J L. Mauk

Subaqueous water-rock reactions that occur at the pit wall/lake water interface can affect the pH of pit lakes. Many pit lake water chemistry models neglect subaqueous reactions, which may create inaccurate predictions over time. A mineral quantification method is presented that defines the wall rock mineralogy of active open pit mines, using samples collected from the Martha Mine, a low-sulfidation epithermal Au-Ag deposit in Waihi, New Zealand. The mineral quantification method has five components: field observations and sampling, X-ray diffraction analyses, selection of representative samples, geochemical analyses, and mineral accounting. Predicted mineral concentrations closely match observed mineral concentrations visually estimated using petrographic techniques. Results of the method can be incorporated into a geochemical model of long-range pit lake water quality resulting from subaqueous water-rock reactions.

Jan 1, 2003

By Bailey JG

There are some thirteen laboratories in Australia in which coal petrological work is carried out on a consistent and routine basis. Applied coal petrological research is conducted by several institutions in different disciplines which can be grouped into four main categories:

Jan 1, 1989

The major heavy industrial consumers of limestone are the cement, lime'and steel ind- ustries. Each of these requires large quantities of cheap raw material. Other ind- ustries such as glass and chemical manufactur- ing are significant consumers and agricultur- al and constructional activities provide additional demand which is usually more local in its occurrence. Limestone is widely dis- tributed throughout Australia but location in relation to major markets, and transport con- siderations render most deposits of no economic value. Among deposits which are sufficiently close to the major metropolitan markets many must be rejected as being unsuitable on grounds of quality, inadequate size for major.develop- ment, or other reasons such as environmental considerations. The major producing locations are sit- uated in a variety of geological environments. Most have limited reserves and require partic- ular attention to quality control. Planned extraction programmes based on detailed geo- logical investigations enable not only satis- factory grade control but also permit, by the adoption of appropriate quarry procedures, the use of sub-grade material, thus optimis- ing utilisation of the available reserves.

Jan 1, 1976

Cleaner Production stands for a proactive and preventive approach to industrial environmental management and aims for process- and/or product-integrated solutions that are both ecologically and economically efficient (æeco-efficiencyÆ). Pioneers in the field were large manufacturing and processing industries in the USA (since the late-1970s), but it took until the early-1990s before Cleaner Production was generally recognised as a valuable approach for large and medium sized enterprises. The application of Cleaner Production in mining and minerals, metals and energy production appears to lag behind other sectors, such as manufacturing and processing. This paper starts with a discussion of the Cleaner Production concept and provides examples of its application from a few selected Australian mining and minerals processing industries. This evidences that Cleaner Production can achieve significant reductions in environmental impact, in terms of reduced waste and emission generation and in terms of conservation of materials, energy and water, while simultaneously reducing operating costs. The paper then investigates a number of key issues pertaining to the implementation of Cleaner Production; ie organisation and management of Cleaner Production activities, effective tools for mastering the Cleaner Production concept as a way of life, and performance measurement.

Jan 1, 2002

By Reynolds JO

This contribution by. The Australasian Institute of Mining and Metallurgy has three main thrusts. First, an Institute (and industry) view on academia and the need for more entrepreneurship at top academic levels, second the need to lift our technological game, and third, professionalism and the perceived role of mineral industry education. While I will deal with each of these separately they are of course inter- related and can be brought together under the frequently used, but insufficiently practised title, "communications". First then, The Institute and industry view of academia. There are some academics in the audience and I imagine they may wish to reply to my remarks with an academic view of industry. That is not unreasonable. Like all human institutions, academic institutions vary in quality and characteristics. Some are successful and some less so. Some historically are well renowned. Others that were once successful schools have declined. Lesser known schools have grown into prominence. What is it that sets apart 'good' highly regarded schools from those that are not so well regarded? It comes down to one main ingredient - "leadership". The strong mining schools in the past 100 years have been strong because they have had outstanding and clearly identified leaders. Strong clearly identified leadership has always had rapport with, and the support of the industry. The two go hand- in-hand, each nourishing and supporting the Other.

Jan 1, 1986

Relationships between lead blast furnace performance and the composition and size distribution of sinter were determined from analysis of lead blast furnace operating data. Sintering plant practice was subsequently modified and substantially improved furnace performance resulted.

Jan 1, 1971

Subsidence issues associated with historic mine workings have highlighted the need for enhanced geotechnical management of the Martha pit over the remaining life. In conjunction with a detailed analysis of pit slope issues a comprehensive geotechnical management plan has been developed at Martha and is being used as the basis for development of similar plans in other Newmont operations.   This paper covers the geotechnical issues facing the Martha operation and the development and application of the management plan.

Jan 1, 2004

By Hutchinson IN

In order for the Australian underground coal mining industry to achieve the high productivity rates demanded of it without compromising its good safety record, improved geotechnical monitoring systems are required. One of the main problem areas affecting underground coal mining is the deterioration of previously stable roadways.CSIRO Division of Geomechanics has been working on a NERDDC funded project to develop an instrument to monitor coal mine roof deformation. The instrument which has been developed, Roof Alert, is a self contained, battery powered, intrinsically safe device. It can monitor the magnitude and rate of deformation and give multiple, variable visual alarm signals where preset levels ate exceeded.

Jan 1, 1991

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

The space probe Magellan is on its way to Venus (May, 1989) and with its sophisticated radar systems will discover much more about our twin planet. There is tennuous evidence that Venus once had liquid water. Did it have life? Why was it not stable and why did liquid water not persist through the period of the dimmer young Sun? These are profound questions for us. We understand why Mars froze when volcanism terminated (Just as Earth will freeze one day) but could Earth boil if we continue to add greenhouse gases (Broecker, 1985). What will happen if 10 billion humans continue to use fossil carbon as their main fuel source? The Earth is warming fast and the new satellite data show that the oceans are warming faster than we thought. Is this just a fluctuation or is the greenhouse signal coming through the normal noise of climate?

Jan 1, 1990