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It is indeed a pleasure to be here this morning to open the 4th Mill Operators' Conference. It is no mean feat to organise such an event and I would like to congratulate the committee for the work that they have done. I am sure that the Conference will be an outstanding success. I welcome overseas visitors and hope that they gain and share in the openness of this Conference. There is personal satisfaction for me to speak to you as a mining engineer addressing a large group of metallurgists and mill operators. I would have thought that it would be impossible for a mere mining engineer to inform a metallurgist of anything. I will desist from using such derogatory terms as "xanthate munchers", "bubble makers" and "glorified mathematicians". Terms of endearment as these may not be seen with much equanimity. Such is the warm association that the two professions have enjoyed over the years. The economic climate that we at present face is a major problem to all of us. I wonder how many people here come from mining operations that are in trouble financially or that are cutting back in one form or another. This is the recession that we needed to have. When the world's greatest treasurer can tell us that then we truly have a lot to fear. The present downturn can be seen as a normal adjustment in the cycle of our business. Yet the world does not experience such severe adjustments as frequently as we experience ours. The root cause for the regular adjustments can be placed at the feet of inflation. Until the politicians of this country of ours can come to grips with inflation, we will continue to experience downturns on a 5 to 7 year cycle. This, in my opinion, is the basic reason why we appear to experience more downturns than the rest of the world. We simply price ourselves out of the market. This takes about 5 to 7 years to be highlighted and then we need to make adjustments. However, this recession is worldwide. The adjustments usually take the form of redundancies, retrenchments and early retirements. What is the solution?

Jan 1, 1991

This paper summarises the performance of the gold exploration industry in the Western World since 1970, with particular emphasis on the period 1985 - 2003. It identifies the number and size of major (ie >1 million ounce) primary gold discoveries made over this period by location and type of company. Estimates are also made of the likely contribution from smaller discoveries down to 0.1 million ounces. It also assesses the overall trend in the percentage of grassroot discoveries that are converted into mines, and the time taken to get them into production. By comparing the discovery data against total exploration expenditures it is possible to determine the average unit cost of finding a major gold deposit. It is significant to note that the average unit cost per discovery and per ounce of resource has tripled over the last 30 years. An attempt is made to determine the overall economic value generated by the industry. This is based on a detailed analysis of the rates of return and the Net Present Values (NPVs) of 109 major gold projects. After including an adjustment for discoveries not modelled, the NPVs are compared against the total amount of money spent on exploration to determine the value-to-cost ratio for the industry. Based on historical spot gold prices and tax rules, it is found that the return on investment for gold exploration in the Western World over the period 1985 - 2003 was around five per cent real after-tax. The returns achieved in the US and Australia was significantly higher than that for Canada. The returns also appear to have declined in recent years. With regard to the relative performance of junior versus major companies, the paper estimates that the junior sector accounted for 30 - 40 per cent of the total exploration expenditure, and were was associated with 34 per cent of the total number of major deposits, 27 per cent of the contained ounces and 25 per cent of the economic value found.

Jan 1, 2004

The major incentives for developing continuous processes for the production of formcoke are to achieve a wider range of coals which can be used, greater operating flexibility enabling the production of various coke qualities, and environmental improvements. The characteristics of a formcoke which must be considered when assessing its performance in the blast furnace are compressive strength, abrasion resistance, volatile matter, reac- tivity, porosity, density, size, shape, ash yield and sulphur content. Lurgi's development work in attempting to pro- duce a formcoke which meets the specified requirements has resulted in most current efforts being concentrated on the Bergbauforschung/Lurgi hot briquetting process. This process blends hot char produced from a non-caking coal with small quantities of caking coal in a special mixer in the plastic range of the caking coal. The material is subsequently briquetted hot, then subjected to a thermal after-treatment to produce a strong abrasion resistant formcoke. A 650 tonne per day plant for British Steel Corporation is now under construction. A study of the equipment requirements and the operating costs indicate that the economics of large scale formcoke plants compare favourably with those of conventional coke-making plants.

Jan 1, 1975

By Evans A. F

Arising out of the increasing demands for efficiency in modern ore-dressing operations has grown a requirement for fuller knowledge of the characteristics of the ore treated. In part, this is being met by improved methods of study of the mode of occurrence of the constituent minerals, and of the intricacies of their physical relationships.A typical instance of the need for such a study is the presence of some undesired mineral in a flotation concentrate or tailing, which may be due either to mechanical association through insufficient grinding, or to incomplete separation in the flotation operation.Again, with modern practice in fine grinding, which often requires that from 70% upwards of the ground ore shall pass a 200-mesh screen, it is obviously impossible to obtain data on comparative grinding efficiencies, for instance, unless there is adequate knowledge of the size-composition of the material passing the finest available screen.Studies like these can be made satisfactorily only after size-separation (which may be carried out conveniently by elutriation) and by actual visual examination with the aid of a microscope, and the minute size of the mineral grains to be examined has necessitated the development of a new technique of sizing and microscopic examination.

Jan 1, 1932

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

Boliden's Aitik open pit mine located in northern Sweden, will expand yearly production from 18 to 36 Mt of copper ore during 2010. The expansion includes a new concentrator located 3 km off the pit, two new apron feeder crushers connected to the ore storages and concentrator with conveyors at a total length of 7 km. The concentrator has two lines with autogenous grinding mills and flotation each with a capacity of 18 Mt. Consequently the mine operation has to be expanded. To achieve this, there was several parallel processes ongoing; investments in new equipment, reorganisations, improvement projects in maintenance and productivity. The Aitik 72 project was started to coordinate productivity and mine planning activities. Initially the long-term strategic mine plan called for a total movement of ore and waste to increase from 40 to 72 Mt but has today increased to 89 Mt. Productivity projects have been focused on load and haul activities such as fuel economics (Renstr÷m, 2007), effective utilisation of trucks partly by increasing manning levels, improved dispatch and shovel utilisation focusing on optimal use of loader/truck fleets. The eco-driving projects previously reported have reduced fuel consumption significantly. This project is also a productivity project, as part of the fuel savings comes from minimising idle engine hours due to queues, break-downs, operator shift changes, etc but also from under and overloading. Effective use of truck fleets, ie transport of material, loading and dumping, thus excluding non-productive engine hours has been an essential motivator when deciding the size and number of new trucks required. This has resulted in a reduction of the investment with at least one but maybe two trucks. A third major project was to optimise shovels together with truck fleet by improving short-term, up to two weeks, detailed planning of drilling and shovel activities. Daily scheduled breaks for maintenance as well as planning of shovel utilisation, down to shift level are included in the production plans. KPIs and online production reports, based on real-time monitoring of drill rigs, shovels and trucks, have been an essential tool used regularly to engage and motivate mine production personal and information reporting to management. Several projects have already reached their goals. The projects will continue throughout 2010 to ensure that productivity targets are met.

May 1, 2010

The Mt Lyell Mine at Queenstown, Tasmania was re-opened in 1995 by Copper Mines of Tasmania Pty Ltd, a wholly owned subsidiary of Mt Lyell Mining Co Ltd. The re-opening followed over 100 years of copper and gold mining at Mt Lyell. Major changes in practice were implemented across the site. Preventing further damage to an already disturbed environment was a major priority. Sublevel caving, at a lower cut-off grade, replaced open stoping for the deep underground mining. Development and later stoping are handled by a contractor, National Mine Management Pty Ltd, in the largest underground contract awarded at the time. Large scale sublevel caving was new to Mt Lyell and not widely practised in Australia, requiring studies and systematic development of the method, particularly in drilling and blasting. Rehabilitation and upgrading of mine infrastructure have been and will continue to be a challenge. The mine has, since 1995, returned to being a stable producer with potential for growth.

Jan 1, 1998

By D Nourry

Optimising the blast is a major issue in the blasting business. It generally means acting on the blasting pattern (drilling, charging, detonating) in order to get a given æresultÆ. This result may either be related to economic reasons, such as the fragmentation influencing productivity, or technical reasons, for example vibrations and projections. Within the frame of the EEC funded Brite-Euram project entitled æBlast-ControlÆ, involving academic research and applied expertise, a general methodology was developed to approach such a problem and currently applied to the industrial partners of the project and final end-users of the generated results. These partners are the limestone ALZO quarry of the CALCINOR group in the north of Spain and the dolomite DMD (Dolomies-de-Marche-les-Dames) quarry of the LHOIST group in the east of Belgium. A first part of the project, over 18 months, was dedicated to establishing a clear relationship between productivity of operations from drilling to primary crushing and the fragmentation resulting from the blast. Extensive monitoring of blasting, production performance and fragmentation data was carried out and automatically collected into a database on both quarries. As expected, it appeared that excessive amounts of fines or boulders were substantially reducing productivity and thus profitability of the operation. Furthermore, an æoptimalÆ fragmentation was assessed for the quarries to run at the best (high throughput, low cost). The second and last part, for the remaining 18 months, was then dedicated to adapting the blasting practice in order to orientate the fragmentation towards a æbetterÆ one. A very common problem normally addressed by any consultant. Nevertheless, the target was not limited to solving the problem for these two quarries, but also to develop a generic method to address this blasting adaptation process and to implement it into a computerised tool. At this stage, it is then obvious that portability of the method and the system are major qualities to be looked for. This paper is aimed to present how this method was developed, how the system was implemented and how it was finally used.

Jan 1, 2001

By M Dorricott

This paper describes the design, construction and performance of sill pillars using cemented development mullock at the Crusader Gold Mine. The orebody is some 35 m - 60 m in length, 5 m - 8 m wide, dipping at 60¦ - 85¦ and plunging at about 40¦ to the north. It is accessed via a footwall decline. The ore occurs at the contact between basalt and ultramafic. This contact is characterised by shearing and alteration; and is prone to unraveling failure. The cut and fill mining method at Crusader extracts 25 m high ore blocks in four flat back lifts and one 8 m thick crown pillar. To enable full recovery of these high-grade crown pillars with minimal dilution, a 5 m thick sill pillar is constructed using cemented rock fill (CRF), after mining of the bottom two lifts in each block. Uncemented development mullock is used as rock fill (RF) for subsequent lifts. Development mullock and cement/water slurry is mixed underground to produce CRF. The fill is transported to the stope in LHDs and dumped on the floor. The sill pillar is advanced progressively, with compaction provided by the loader driving over the previously placed fill. Old jumbo rods are installed as shear pins along the flat dipping hangingwall to reduce the risk of rotational failure of the pillar. A fan of cable bolts is installed into the hangingwall to prevent unraveling failure in the sheared ground. Buffer blasting is used to minimise damage to the CRF sill pillar when the crown pillar below is extracted. At the time of writing, extraction of the crown pillar underneath the CRF has taken place at the 930 stope. The crown pillar was extracted successfully with dilution from the backfill and hangingwall minimised and 98 per cent of the gold recovered. This compares with pillars that were mined beneath uncemented backfill where only 70 per cent of the gold was recovered and where there was significant dilution from the backfill and from hangingwall failures. Where no CRF was placed, there were also numerous production delays caused by large rocks from the hangingwall blocking the stope brow.

Jan 1, 2002

Mineral exploration and development can have a significant impact on the environment and local communities, in some circumstances extending well beyond the mine site. Poor environmental performance and consequent social impacts by some companies have affected the reputation of the whole industry to the extent that the principal public concern about mining is its impact on the environment. This is consistent with public attitudes about other major natural resource sectors such as forestry and commercial fishing. Traditionally the community has relied on governments to set the benchmark for acceptable environmental and social performance through establishing and revising regulations governing the mining industry. This however assumes that regulations keep pace with community expectations. It also does not take into account those circumstances where governments can have conflicting roles as both watchdog and project partner. Government regulations and industry self-regulation are not in of themselves sufficient for the minerals sector to demonstrate that it has adequately addressed environmental and social issues associated with the sector. For the minerals sector to improve its reputation it must first improve its environmental and social performance. To do this requires the sector to operate to acceptable standards of environmental and social performance and for the sector to be able to credibly communicate this to its stakeholders such as investors, non-government organisations (NGOs), customers, staff, regulators and local communities. Independent third party certification of environmental and social performance (æcertificationÆ), already operational in forest and fisheries management, is proposed as a mechanism to enable the minerals sector to achieve this. World Wide Fund for Nature (WWF) and industry partners will be collaborating in a project to ascertain the applicability of æcertificationÆ to the minerals sector. A number of economic, social and environmental benefits are identified that could accrue should mining companies be able to differentiate themselves on the basis of environmental and social performance, an attribute evident in æcertificationÆ schemes. External audiences are seeking increasing levels of information and data on environmental and social performance of mining companies, be it local communities, investors, financial institutions or NGOs. Environmental and social reporting should be a key communications device that stakeholders can rely on as a reliable, credible source of information on environmental and social performance. WWFÆs contribution to the debate about environmental and social reporting has been to develop a process to assess the quality of environmental and social reports against reporting ingredients which WWF believe are important if a report is to be an accurate reflection of the reporting entitiesÆ environmental and social performance.

Jan 1, 2002

By Partridge AC

The measurement of particle size is very important in many industries. Comments in this paper refer principally to the Mineral Industry and in particular to Coal Mining and Coal Preparation. The objective is to indicate the importance of particle size in process design and process assessment and to describe techniques for particle size measurement and the presentation of results.

Jan 1, 1984

The treatment of steels with acid solutions for the removal of oxide products represents possibly the largest outlet for chemicals in steel processing. Organic pickling inhibitors are required to prevent base metal attack by these acids otherwis

Jan 1, 1980

Surface geological observations are predominantly two-dimensional but can be expanded into three dimensions using geophysical techniques. These techniques have proved succ- essful in the past and will be utilised more frequently in future mineral exploration. Geophysical training establishments must recog- nize future requirements and teach geophysics as part of a broad earth science course as well as a specialised geophysical course. Central- isation of teaching skills, the use of high- technology in the classroom, and greater interaction between academic and industry staff are recommended as a means of ensuring a vibrant geophysical training base in Australia, for the geophysicist of the future.

Jan 1, 1986

This paper looks at the problems associated with surface settlements and other subsidence effects from the underground extraction of coal in relation to consent applications under the Resource Management Act. The main features of subsidence are examined with respect to identifying the adverse effects as defined under the RMA. Particular attention is paid to sites where little or no data is available as in the case of greenfield sites or at mines where new or different mining methods are being introduced. In these situations it is not possible to make accurate predictions of settlements or strains and therefore other factors need to be considered. The long term effects which might occur post mining are examined in relation to mitigation and management options.

Jan 1, 2003

Activated carbon is ideally suited to treating low grade ores and tailings by the carbon-in-pulp process and is rapidly replacing the use of zinc for recovering gold from cyanide leach solutions. Coarse carbon particles derived from coconut shell adsorb up to 30,000 ppm Au as a gold cyanide complex and can leave barren solutions containing

Jan 1, 1982

Gold mining commenced at Telfer in Western Australia in 1977. Ore mining was carried out by owner equipment and personnel with waste stripping by a contractor. Initial ore reserves were in predominantly high grade, geologically simple reef structures. A mining method was developed using dozers to selectively mine the ore bearing horizons with a minimum of dilution. As the mine has developed the simple, high grade ore reserves have been progressively replaced by more geologically complex, lower grade reserves. In turn, mining methods have evolved to extract this ore by the most appropriate methods. On-going attention to ore mining practices will ensure that project profitability and viable mine life are optimised.

Jan 1, 1986

By Mackenzie JMW, Virnig MJ, Kotze MH

A new range of solid and liquid ion exchange extractants for gold based on the guanidine functionality is described. These extractants have pH versus gold extraction isotherms which lie between those of the conventional weak base and strong base resins which have previously been studied as aurocyanide extractants. Possible applications of these new extractants in gold recovery are discussed.

Jan 1, 1993

By Whiteley M, Robinson T, Vernon B

The Western Australian gold industry has approximately 100 operating plants, mainly CIP/CIL. The nature of the State's rapidly expanding gold industry gave rise to concerns over management of the cyanide hazard, in that most plants are remote from major population centres, have a workforce with a high turn over and use highly saline process water. Approximately 4,500 workers in the industry have the potential to be exposed to cyanide in the course of their normal work.This paper outlines the risk management strategy developed by Government and industry to monitor atmospheric HCN gas in the work environment and the role of continuing education and training along with regular site inspections by Department of Mines Inspectors.

Jan 1, 1990

Systematic ICPES (Inductively coupled plasma emmission spectrometry) analysis of magnetic concentrates from drainage samples has been used to discriminate concentrates dominated by magnetite from those dominated by pisolites, presumably maghemite-rich. In addition, a set of spurious zinc enhancements was recognised and explained with the help of mineralogical data, and systematically isolated using chromium as a Discriminator.

Jan 1, 1987

Maximising margins in highly competitive international markets demands superior productivity. A key to superior productivity is using a process approach to enable rapid, ongoing improvement of production, commercial, administrative, marketing

Jan 1, 1998