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By D Cioclea, I Toth

Coal mining can lead to the occurrence of spontaneous combustion events. If these events are not prevented they can give rise to fires that have major adverse effects on the mine plan. After studying the chemical structure of coal, the theories of self-ignition and of the oxidation reaction of the organic compounds, two new technologies have been developed for fire prevention based on the inhibition of coal oxidation. The first technology consists of spraying water drops mixed with inhibiting substances into goaves. The second consists of the infusion of a mixture made of several chemical compounds. Tests performed in situ showed the new inhibition technologies to be highly effective even for longwalls mining coal with a high reactivity from the point of view of self-ignition.

Jan 1, 2005

By M.E. Crump

Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-' and varies widely from place to place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO. colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed that heating the mud to 500 -600¦C for 1 hour followed by acid/alkali treatment gave complete recoveries.

Jan 1, 1995

The strategy of adjusting operating conditions to maintain optimum process performance as the feed quality varies - adaptive optimisation - is being investigated by computer simulation of chemical processes for the treatment of ores. Those ore-process systems that are most likely to yield substantial benefits from adaptive optimisation are being identified as a guide to the selection and development of systems for practical application. The generalised mathematical representation of the cost structure, ore quality variations, process kinetics, reactor characteristics and operating variables for ore-process systems is described. Results are summarised for temperature, reagent concentration or residence time as the manipulated variable. For almost all systems, adaptive optimisation was economically beneficial, although a few exceptions have been identified where there is a significant synergistic effect between poor-performance and good-performance materials in a blended feed. The sensitivity of the benefits of adaptive optimisation to a range of economic and technical factors is summarised.

Jan 1, 1985

By K Knorr

Desktop X-ray powder diffraction using a D2 PHASER equipped with fast linear detector was performed on several iron ore and mill scale samples. Data were analysed using cluster analysis and Rietveld quantitative phase analysis. The quantitative mineralogy of both materials could be established. Thus the input is provided for understanding the energy consumption and the CO2 emission during iron production. Furthermore, tabletop XRD allows to distinguish iron ore from mill scales and to quantify their mixtures.

Jul 11, 2011

By Schmidt LC

The method of supporting excavated roofs in underground coal mines by conventional roof bolting systems is challenged due to its shortcomings of being time-consuming and leading to possible unsafe installation. Though a few alternatives have been considered, the ultimate and most efficient bolting method has often been conceived as one using a self-drilling roof bolt, or a Rapid Face Bolting System (RFBS). The on-going Rapid Face Bolting Project undertaken by the University of Wollongong includes a special tubular bolt design.The tubular bolt designed for the RFBS is a "single-pass" bolt equipped with cutting tips used to drill a bolthole to accommodate the bolt. Different from that of the coring bit employed in geological site investigations, the principal design consideration for the tubular bolt is low cost associated with a small working life for the cutting tip.

Jan 1, 1991

The Lennard Shelf Operations owned by Western Metals Ltd evolved from the Cadjebut Zinc Lead Mine (BHP) in August 1994. Original production of 0.5 mtpa will rise to 2.0 mtpa at the end of 1998. Employees work a multiple of fly-in/fly-out (FIFO) rosters from the Kimberley region and the WA Capital. The three underground mines, treatment and services departments will employ approximately 300 people by the end of 1998. The expansion of the Lennard Shelf Operations as a remote mining location was based on a fresh look at management systems and employee rosters which were generated from many years of mining experience. This paper will endeavour to summarise these experiences and analyse some of their outcomes. Dealing with several mining methods, engineering difficulties, logistical problems and climate extremes, the Lennard Shelf Operations has managed social/employee issues with excellent results. Much time has been spent to get this correct for the Lennard ShelfÆs own set of circumstances. Employees and associated companies must expect continuing changes and improvement as Western Metals strives to continually improve its management systems and employee rosters.

Jan 1, 1998

Natural gas was introduced to the Melbourne reticulation system in April 1969 and since that date sales to industrial consumers in the Gas & Fuel Corporation of Victoria area of supply, have increased by over 50% This increase has occurred despite the fact that the areas in which the new fuel is available have been dependent on the progress of the conversion operation from manufactured gas. The half way mark for conversion was reached in May 1970. The reason for the adoption of natural gas by industrial users is usually the result of objective financial analysis leading to the conclusion that the new fuel will give the lowest overall production cost. Many factors are involved in such an analysis of which the price of the fuel is only one. Amongst other important elements in the cost calculation are:- -ò òò -(1) The effect of fuel on product quality (2) Maintenance and handling costs for alternative fuel. In addition to economic gains for the individual user, the use of natural gas should benefit the whole community through its effect on such things as, air pollution and overseas balance of payments.

Jan 1, 1970

Almost all industrial products, such as buildings, cars, plastics, railways, radio and television sets, computers, and others are made from materials extracted from the Earth. Earth is main resource of energy and up to now; the energy has been derived mainly from natural resources. Mining industry has significant influence to the nature, sometimes evokes a devastation of nature. On the other hand we have got a lot of nice examples that good preparation, sensitive mining practice and consistent reclamation can minimise the negative effects. All the mentioned problems calls for effective tools for mine design, mine operation and mine reclamation. Third millennium brings next challenge given by advances in information and communication technology. The development of very sophisticated software tools provides to technical systems some features of autonomous æthinkingÆ and intelligent behaviour. We can find large effort and a lot of scientific papers reflecting last advancement in science and technology and providing inspiration for new mining technology of third millennium called Intelligent Mine. Some aspects related to creation and utilisation of æIntelligent ModelsÆ as a background of æIntelligent MineÆ are presented and discussed in this paper.

Jan 1, 2003

A feasibility study will fail its objective if it does not identify and then correctly assess, all the risks which could have a substantial impact on the financial viability of a project. Before this assessment can be undertaken, one needs to understand the risk profile of the entity which is making the decision about the project. Some of the commonly encountered issues when assessing project risk are related to the problem of not being able to see the wood for the trees. In any risk analysis it is important that conservatism does not strangle a viable project; that the variables are internally consistent with each other, that reality checks are carried out and that appropriate expertise is used. Sensitivity analysis forms a part of the overall project risk assessment; however, it can only test those variables which have already been identified in the financial model. The most useful tool in performing a sensitivity analysis is Monte Carlo simulation. When properly used, it provides a more real world scenario than the simple adjustment of key variables by ¦ 10 per cent one at a time. Monte Carlo can provide valuable information about the robustness of a project. Project risk and sensitivity assessment is prone to the analysis paralysis syndrome. The focus should be on quality rather than quantity.

Jan 1, 1997

This paper compares and evaluates the impact of income tax and value-added tax on the decision to explore for minerals or to develop a mine in four countries: Australia, Papua New Guinea, Argentina and Indonesia. Three aspects are considered in depth:- domestic tax rules applicable to mining projects;- taxation of foreign mining investment and foreign providers of expertise;- taxation of project finance (other than equity) from foreign sources.Specific tax issues discussed include tax deductibility of various costs, treatment of tax losses, special tax incentives, comparative treatment of various corporate structures, non-resident withholding taxes, and tax costs of various forms of project finance. The paper also illustrates the comparative impact of income tax on rates of return by means of a simulation of a mining project in each of the four countries. The simulation demonstrates why the highest rate of return may be obtained in Argentina and the lowest in Australia.Relevant features of the income tax systems in each country (at 15 February 1990) are summarized and compared in several tables annexed to the naner.

Jan 1, 1990

Discounted cash flow (DCF) methods are well suited and recommended as a primary valuation method for mineral assets for which there are at least indicated resources and some form of feasibility study containing engineering, production and capital and operating cost data. DCF methods are also applicable as a secondary or check valuation method for exploration properties for which no technical study has been prepared. For projects where little or no engineering, production and/or cost data is available, the process of formulating a project concept by specialists who do not possess experience and expertise in the relevant technical faculties is totally rejected as a basis for applying DCF techniques as a primary valuation method. Such an approach runs counter to The Australasian Institute of Mining and Metallurgy (AusIMM) requirement to apply relevant expertise to specific aspects of mineral valuation. Technical and commercial inputs to mineral valuation should be reviewed by specialists who have specific expertise in the relevant disciplines, and should be tempered by the quantity and quality of technical evaluation which has been undertaken and the development status of the asset.

Jan 1, 1994

The geotechnical and environmental aspects of heap leaching are very closely tied during design, operations and closure. Potential environmental impacts from heap leaching are mostly due to land disturbance and water quality issues, including both groundwater and surface water. Water quality issues are mostly related to containment design, which is primarily a function of proper sizing of the facilities and site specific liner design. Geotechnical analyses is the dominant discipline in providing cost efficient, operationally effective and environmentally sound heap leach facility designs. Much has been published on geotechnical aspects of heap leach design, for example Van Zyl, Hutchison and Kiel (1988) and Van Zyl (1987). This paper will emphasize a few specific aspects related to the geotechnical and environmental consideration for heap leach projects. These aspects are: ò site investigation; ò containment design; ò slope stability; ò heap flow dynamics; and ò closure design. Design of a heap leach project must consider not only the operating life but also closure and post-closure considerations. As a matter of standard practice, designing for closure is an extremely important concept. Not only is it important for environmental aspects, but experience also shows that projects designed for closure will be overall more economical for the total life cycle of the project. Closure considerations are also important during project feasibility evaluations to ensure that total life cycle costs are evaluated.

Jan 1, 1994

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

The Bowen Basin of Queensland and the Hunter Valley of New South Wales are the two largest black coal producing areas in Australia. Mining activities require the availability of large on-lease storages for water and tailings. The legislative framework for the regulation of large dams is slightly different between the states. The paper provides a broad outline of the regulatory framework in each state, with particular reference to Queensland and New South Wales. In New South Wales, water storages and tailings dams are treated similarly by the regulator. Under the Queensland Water Act 2000, now proclaimed, referable dams are restricted to water supply dams the failure of which involves population at risk downstream. Tailings dams are excluded, being deemed hazardous waste dams regulated under the Environment Protection Act 1994. These storage facilities are required to include a ædesign storage allowanceÆ so that the possibility of spillway discharges is minimised. New South Wales is moving toward this requirement. A curious anomaly is emerging in Queensland: the legislative definition of hazardous waste û material resulting from the processing of minerals û does not extend to coal tailings since coal is not included in the definition of a mineral. The paper explores this and other ramifications for mining operations of the new legislation as well as general trends in criteria affecting the cost of providing water and tailings storages.

Jan 1, 2003

By Rolley P

In the course of reviewing grade control practices at the Marvel Loch gold mine in Western Australia in 1992, FSSI Consultants developed and implemented a novel approach to ore selection using a method to maximise financial return (the MP method*). The approach was based on improved grade control sampling and an ore selection method which directly incorporates both a measure of the uncertainty in knowing the true grade of selection units in the definition of ore, as well as the operating cost and revenue parameters of the mining operation. During the past four years, FSSI Consultants have evaluated and refined the use of this approach and have implemented customised variations of the MP method at seven gold mines and a gold-copper mine in Australia. The previous methods of ore selection at most of these operations were based mainly on polygonal - sectional methods of grade estimation. At all of the sites where grade control optimisation has been given a fair trial over several months of production, the use of the MP method has been consistently rewarding to the mining operations. The benefits include increased run of mine ore stockpiles and low-grade stockpiles and decreased fluctuation in the production grade. Most operations have also benefited from a consistent ability to improve production grade through high-grading of the increased ore production. The increase in ore production has the logical benefit of reducing stripping ratios, increasing mine profitability and mine life.

Jan 1, 1997

By Luck D

Current methods of mucking out small development tunnels are a major limitation to improved efficiency and high rates of advance. This is particularly true in the deep metalliferous mines of South Africa, where the harsh environment, remoteness of operations and the hard abrasive rock conditions mitigate against the use of the tunnel borer type of equipment. The Loader Distributor Train was designed to overcome the special problems of hard rock tunnelling. It combines advanced innovative technology with proven simple methods of operation and maintenance. The system aims at taking advantage of new, efficient and cost effective power sources in South African mines based on replacing compressed air with electro hydraulics and the new concept of hydropower. It also introduces electronics and computer technology, for both automatic control and fault finding, into the production environment. The system is designed to permit sophisticated equipment to be operated and maintained by a semi skilled labour force. Although still undergoing trials it is believed that the Loader Distributor Train will prove highly effective, and that the new concepts offer considerable potential in areas other than flat tunnels, in particular the cleaning of inclined shafts.

Jan 1, 1986

I began my interest in sample preparation when I joined the Institute of Nuclear Sciences in 1962. I worked in the fields of rock dating and stable isotope geochemistry. Preparing a sample could take several days and the analysis took another day or more, so great care was taken with each sample. In 1968 I changed to mineral exploration analysis and was surprised to find that there was much less care in how a sample was taken and prepared. Virtually every sample was processed in the same way. In the use of ring and puck mills, Australia and New Zealand were among the world leaders. It took another ten years before labs in North America changed over from disc mills. In 1975, my partner and I divided our business into two parts. He took the laboratory into his consulting laboratory business and I took the small business that we had started, making ring and puck mills. For the next six years I was RocklabsÆs only employee. In the 1980s and 1990s, sampling specialists like Francis Pitard and Dominique Francois-Bongarcon began to make a difference in the understanding of what constitutes good sampling and preparation practice. They and others took courses on the new concepts of Sampling Theory, as developed by Pierre Gy. The desire for better procedures lead to the development of new machines, including the big bowl pulverisers from Australia, jaw crushers that could crush finely like our Boyd Crusher, rotating dividers of new designs and flow-through ring and puck mills. Other machines did not fare so well, including rolls crushers, cone crushers and hammer mills.

Jan 1, 2008

The karst water system in Han-Xing District is charaterised by heterogeneity in karstification and permeability of the limestone aquifer, unsteady flowing of the groundwater along karst runoff zone system, periodic recharge related with the periodic precipitation, and concentrative discharge of the groundwater in the form of karstic spring groups. The basic law is that the quantity of the water is very large during waterflood period and rather small in dry period, which has brought about difficulties and contradictions in mining and water supply. The measure to bring the karst water under control must be based on the principle of comprehensive ways and on the systems engineering method. Macroscopiclly, it is the reasonable countermeasure to retain surface water in the upstream section of the karst water system and to strengthen infiltration in the midstream section and to combine exploitation and utilization of the groundwater with water protection and mine dewatering in the area in which mines are distributed.

Jan 1, 1988

On the face of it this is an easily answered question. Modern technology and life as we know it today would be impossible without industrial minerals and the responsible utilisation of mineral resources is essential for the economic wellbeing of the nation. The quarrying industry supplies a high percentage of the industrial minerals used in New Zealand and our role therefore, is to ensure a constant supply of high quality roading and concrete aggregates so that society and the community as a whole can develop. We must do this in a manner which causes the least possible disruption to members of the community, which efficiently utilises all the valuable resources, which causes as little pollution as possible and last but by no means least, creates realistic profit for the operator. It is only by achieving a reasonable profit that we are able to continue in business and therefore play our part in the development of the country. Unfortunately, quarries have a poor image and are not generally popular, as on the whole, they are noisy, dirty and dusty and attract large trucks which create traffic problems. Judging by the amount of restrictive legislation with which we have to comply today, not even government or the local authorities want quarries which presents the industry with some serious problems, some of which will be outlined in this paper.

Jan 1, 1978

Accidents in open pit mining have a high cost in lost time of person- nel, damage to equipment and installations, and lost production. The realities of export competition require that Mine Management sig- nificantly reduce the costs associated with accidents and workplace ill-health. Newer management approaches are proving effective in reducing the Total Cost of Risk through a strucured Occupational Health and Safety Programme exhibiting the following features: ò Formal Company Policy ò Accountability for OH&S performance clearly designated to each level of management and supervision ò Effective utilisation of a Mine Occupational Health and Safety Co- Ordinator and a Mine Occupational Health and Safety Adviser ò Development of realistic OH&S Objectives ò Training of Management, Supervision and Workforce in Occupa- tional Health and Safety ò Development and adoption of Safe Work Practices and Procedures ò Effective employee selection procedures, control of Contractors ò Monitoring of the health of the workforce ò Collection, recording and distributing information on all Mine inci- dents, accidents, injuries and damage ò Ensuring that the Mine environment is healthy and safe ò Effective Emergency Procedures to deal with injury, fire, rescue and other situations of risk ò Controlling those Mine hazards which cannot be removed ò Adopting a high standard of Occupational Rehabilitation ò On-going visible Management participation in the programme to ensure that momentum is developed and maintained. This approach requires that Occupational Health and Safety be given equal status with product quality, maintenance of plant and output per- formance; its implementation is rewarded with improved morale and major cost reductions.

Jan 1, 1989