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By A Maurer, N Pereira

Low-density explosives have been developed with trials being conducted for over 20 years and yet have still only gained limited market acceptance despite producing some very promising results. The biggest concern with industry acceptance has been disbelief that a product with lower density than the ANFO benchmark could fragment anything but the weakest of strata. Trials have been carried out with products such as diluted ANFO, low-density ammonium nitrate (AN) and various other mixes, although it has been only recently that low-density explosives have been accepted as a serious alternative to traditional products such as ANFO and heavy ANFO. The recent uptake of low-density products has been the result of several key factors: the current resources boom forcing AN supply issues, the development of new handling techniques, and a far better understanding of the utilisation of such products. This paper highlights the benefits of low-density products available in the market and focuses on the situations where low-density explosives can provide the end user with benefits that would otherwise be achieved through more time consuming methods. Through correct implementation, low-density explosives can provide the blast designer with another option when looking at the optimum method of breaking the rock. This while still controlling the other limiting factors such as cost, environmental impacts (noise, vibration, dust and fumes), coal damage and safety (stable walls).

Jan 1, 2005

Due to collapsing copper prices during 1974/75, a rapid changeover was made at the C.S.A. mine from mechanised cut and fill stoping with incline access to the more economic long hole open stoping method. In 1974/75, 20 per cent of total production came from open stopes. For the 1976/77 year-to- date, more than 80 per cent of total production has been won from open stopes. As a result, mining performance has improved considerably. Stops, drilling performance has increased by more than 50 per cent since the changeover from extension rod, 50 mm diameter cut and fill uphole drilling to 115 mm diameter in-the-hole hammer drilling of holes up to 65 m long. Stops blasting performance has improved from 750 tonnes to 950 tonnes blasted per manshift. Open stope primary blasting per- formance is much higher, but reduces to 950 tonnes per manshift when secondary blasting and firing of hung drawpoints are taken into consideration. Ground control, the most expensive and least productive aspect of cut and fill mining, is almost entirely eliminated in long hole open stoping.

Jan 1, 1977

Over the past several years, copper prices have surged from under a dollar to over three dollars a pound. However, the long-run trend in real copper prices since at least the early 1970s has been sharply downward. While many now contend that the long-run trend in real copper prices is now upward, the result of structural changes in this market, others are sceptical. Nor is copper unique; the prices for a number of other metals, including aluminium, iron ore, lead, nickel and zinc, have followed similar patterns. This paper examines the forces behind short-run and long-run trends in metal prices. It first focuses on the short run, where it argues that shifts in demand are largely behind changes in prices. It then turns to the long run, where it concludes that production costs and supply largely govern price trends. Finally, it explores several implications of these findings, including those for diversification and market risk, for forecasting mineral prices, for assessing the growth of metal demand in China and elsewhere on metal prices, and for changes in the long-run price trends.

Jan 1, 2006

The paper sets out the context for water and the challenges that have to be faced in the battle to alleviate global poverty. It acknowledges that the world has been blessed with abundant water but because of population and development pressures, and the projected changes in climate, avoiding serious water shortages in some places will be difficult. MiningÆs use of water is placed in context and the paper then considers the specific threats to the industry in terms of availability and price and the need to find mechanisms to deal with the issue of resource degradation caused by abandoned mines. Rio TintoÆs use of water is then set out and three examples are given of how different water challenges have been addressed. The paper goes on to consider each element of a water strategy designed to move Rio TintoÆs performance towards excellence. This strategy incorporates improved management procedures (policy, principles, standards and targets), performance enhancement (through use of the Rio Tinto Water diagnostic and technology changes) and working with others in the academic and NGO community who seek to address the same global issue.

Jan 1, 2003

By Player WP

The legislative operating environment, or the mineral regime, that a country has to offer is one of the key determinants that a company wanting to invest in an area takes into account in formulating its investment decision. The New Zealand Government recognises this and the importance of getting the regime right in order to provide for continuing investment in mineral exploration and mining in New Zealand. In recent years, the Government has given considerable attention to developing legislation which provides for investment to take place; for those making the investments to have a stable, fair and open investment environment with government intervention only when considered absolutely necessary because other approaches are not working; and for the people of New Zealand to know that investment must meet acceptable health and safety standards and have acceptable impact on the environment. Also of key importance is having a clearly defined mining regime which includes rules on how to obtain a permit and rules in respect of ongoing permit compliance, rights to develop a mineral resource and permit conditions (in particular, the royalty regime). In New Zealand, these matters will all be addressed in what are referred to as "minerals programmes".

Jan 1, 1995

By Mouritz M

Ventilation characteristics and the occurrence of nocturnal surface inversions have been investigated within the Mount Whaleback open cut iron ore mine at Newman in Western Australia. When winds are light and/or nocturnal surface inversions form within the pit, episodes of atmospheric stagnation can occur with resultant accumulation of dust, diesel exhaust fumes, and sulphur dioxide evolved from spontaneous combustion of pyritic shale. Nocturnal surface inversions were recorded outside the mine on more than two-thirds of nights. Inside the pit, inversions were much less frequent - occurring on roughly 20% of nights when they were observed outside - and much weaker - the maximum temperature difference being 5 C¦ over 210 m inside the pit compared with 15 C¦ over 150 m outside.

Jan 1, 1988

By Menne DM

The carbon-in-pulp (CIp)process has become well accepted and firmly established in the gold industry of South Africa and, at this stage, six large CIP plants are treating close to I million metric tons of material per month. Many small operators are also using CIP and additional large plants are either nearing completion, are on the drawing boards,. or are being considered. The programme of testwork that preceded the acceptance of the CIP process in South Africa was conducted over some eight years and has been previously described'-7. With the start-up of the President Brand CIP plant on 'calcine' in July 1980 and that of the Western Areas CIP plant on repulped filter residues in September 1980, the emphasis on the CIP process switched from pilot plants to these large plants - and has largely remained there. As it has started up, each new CIP plant benefited from the experience gained and the developments made, on earlier plants but, since so few plants have so far been established in South Africa, each new plant and each new design has revealed a further set of conditions to be met and problems to be overcome. However, in the highly collaborative atmosphere of the South African gold-mining industry, the results and observations from the operation of these first plants were shared by all mining groups. This paper will attempt to describe typical developments on, and results obtained from, these new large plants, and will incorporate significant results from the earlier laboratory and pilot-plant investigations.,

Jan 1, 1982

The paper deals with the problems of grouting methods for fissured-porous rock. The paper describes design procedure, injection process patterns and hydrodynamic testing techni- que to plan grouting programs for fissured-porous aquifers. A number of case histories is given to illustrate the imp- lementation of developed methodology at various mining pro- jects.

Jan 1, 1988

During the 20th century, the iron ore mining industries of Canada and the United States passed through several periods of transformation. The beginning of the 21st century has seen yet another period of transformation, with the economic failure of a number of steel companies, the acquisition of their facilities by more viable steelmakers, and the consolidation of control within the North American iron ore industry. Changes in Canadian and United States iron ore production and the market control structure involved are analysed. The consolidation of ownership, formation of foreign joint ventures within North America, planned divestitures of upstream activities by steelmakers, and industry changes made to ensure availability of feedstocks will be reviewed. The traditional isolation of the Canadian and United States iron ore operations and their strong linkage to downstream steel production will be discussed in the context of a changing global economy. Management-labour conflicts that have taken place and agreements made during 2000 through 2004 will be discussed in the context of the economic environment leading up to these agreements. Cooperative agreements between competing Canadian and United States companies to resolve client needs in processing and blending will be examined. A joint industry-government project designed to use new technology to produce direct reduced iron nuggets of 96 - 98 per cent iron content using non-coking coals will also be assessed. Changes in iron ore transportation methods, ownership and infrastructure will be reviewed for both rail and inland waterway transport between Canadian and United States companies. A brief analysis of social and environmental issues relating to sustainable development of the Canadian-United States iron ore industry will be included.

Jan 1, 2005

The paper describes major principals in hydrodynamic test- ing of horizontal and inclined boreholes using flowmetering and pressure build-up techniques while tunnelling and dri- ving permanent workings through water bearing rock and fau- lted zones. A number of case histories is given together with the description of technical means and special equip- ment.

Jan 1, 1988

Forty two new apatite and zircon fission track analyses on the Kubor-Marum-Bena Bena area of northern Papua New Guinea severely constrain the timing of tectonic events and hence the tectonic models for New Guinea, particularly arc-continent collision. In addition, the data can be analysed regionally in terms of known and assumed lithospheric fault zones inferred to control mineralisation (eg. Corbett 1994; Kendrick et al 1995; Hill et al 1996) to determine reactivation of these zones. When combined with the new kinematic plate models for the evolution of New Guinea (Hall 1997) there is the potential to predict likely zones of mineralisation. The low-medium grade? Palaeozoic rocks of the Bena Bena terrane yielded a zircon fission track age of 17 Ma, indicating the time of cooling below 200¦C. The age is consistent with `the shift, at about 16-18 Ma, from volcanolithic sediments to mixed provenance sediments rich in quartz and metasedimentary lithic fragments in the southern Finisterre Ranges (Abbott et al. 1994). This shift was recorded in the Sukurum Formation, which ranges in age from Middle Miocene to Pliocene with quartzose and metasedimentary grains in all samples. Although recording rocks at temperatures of 200¦C and hence depths of ---5km, the 17 Ma age suggests the Bena Dena terrane was rapidly cooling at that time due to uplift and erosion, supplying metasediments to the southern flank of the Finisterre Range, currently 100 km to the east. Significantly, the Middle Miocene Akuna Intrusive Complex, dated 14-17 Ma by Page (1976), lies almost entirely within or adjacent to the Bena Bena terrane. Potentially the uplift, erosion and cooling of the terrane at 17 Ma may have been caused by the rising plutons. If so the 800 sq km exposure Akuna Intrusive Complex at the SE end of the Bena Bena terrane may have been the focus of uplift and supplied the metasedimentary detritus to the Finisterre Range. This suggests that the Finisterre Range was not far removed from the Bena Bena terrane, perhaps less than the 200 - 400 km indicated by Abbott et al (1984). The Akuna Intrusive Complex probably resulted from subduction of the Solomon Sea Plate beneath the PNG margin. In order for the subducted slab to reach depths of -100km below the area to facilitate partial melting and plutonism (Hamilton 1994), subduction probably commenced 3-5 Ma Ma before plutonism, ie at or prior to 20 Ma suggesting a significant change in the tectonic regime at -20 Ma, perhaps related to collision of the Solomons - Ontong Java Plateau collision (eg. Hall 1997). The main result to emerge from the 28 apatite fission track analyses is that the whole of the study area underwent rapid cooling due to uplift and denudation in the Late Miocene, mainly between 7-10 Ma. Results from several samples indicate that they were not totally overprinted prior to uplift indicating maximum burial of -3 km in the Middle Miocene, assuming normal temperature gradients. The burial is less if higher gradients are assumed, allowing for Middle Miocene plutonism. The Late Miocene cooling in the Mobile Belt agrees well with the Pliocene to Recent cooling in the Fold Belt to the SW, interpreted to be due to uplift and erosion associated with fold and thrust deformation of the Miocene Limestones (Hill & Gleadow 1989). This timing relationship suggests, that compressional deformation in the Mobile Belt occurred in the Late Miocene, at 105 Ma, and that the deformation migrated towards the undeformed foreland in the southwest in the Pliocene, at 5-2 Ma. The regional Late Miocene uplift and denudation in the Mobile Belt is also consistent with that postulated by Crowhurst et al (1996; 1997) for northwest PNG, although they considered the event to have occurred mainly from 8-5 Ma. If so, then the uplift and denudation may have been migrating from east to west as well as to the south into the Fold Belt. These timing relationships place significant constraints on tectonic models for the area, indicating that the major compressional pulse in PNG commenced in the northeast at -10 Ma and migrated to the southwest and west in the latest Miocene to Pliocene. This suggests that the initial arc-continent collision and associated shortening occurred in the Late Miocene around -10-12 Ma. This immediately followed intrusion and cooling of the Akuna Intrusive Complex at -17-14 Ma and the Bismarck Intrusive Complex at -12.5 Ma (Page 1976), indicating a linkage between the end of plutonism and the start of compressional deformation. The timing is consistent with the observation of Hamilton (1994) that in areas of subduction `the common regime in overriding plates is extensional and leading edges are crumpled only in collisions. This suggests that the Middle Miocene magmatism in northern New Guinea occurred during extension above a subducting slab and was terminated by Late Miocene arc collision and resultant compression commencing at -10-12 Ma. In general, these data indicate that the acme of denudation and cooling in the Mobile Belt was in the Late Miocene, with relatively little denudation there since. In contrast, Hill & Gleadow (1989) found that the peak of denudation in basement outcrops in the Fold Belt was in the Pliocene at -4 Ma. However, in this study some samples from the Mobile Belt yielded Pliocene ages or high

Jan 1, 1997

By A Struminski

The principles of occupational risk evaluation resulting from the improper ventilation of the underground mines were presented. It was shown that the risk level implies the appropriate planning and usage of prevention methods. That approach is fundamental in the ventilation, fire and climate safety management in the copper ore mines. The paper uses the adequately modified Risk Score method.

Jan 1, 2003

East Nelson and Marlborough, in the northeast of the South Island, contain a wide variety of metallic minerals, including gold, silver, copper, chromite, antimony and scheelite, but no sustained metallic mining industry has evolved. Gold was the most sought-after mineral during the first century of European settlement and numerous discoveries were made but these failed to live up to expectations. While traces of gold are widespread in east Nelson, including in quartz veins in Nelson City, no payable deposits were found. In Marlborough the probability of a gold discovery had initially seemed remote but all this changed with the finding of rich deposits in the bed of the Wakamarina River in 1864, which provided a much-needed boost to the provincial economy. However, the decline of gold mining in Marlborough began virtually as soon as it had commenced. Extensive floods in 1865 hastened the exodus of miners to the profitable new fields of the West Coast.

Jan 1, 1993

A unique opportunity is presented to Australia by recent developments in the Carpentaria and Mount Isa Mineral Province.Unique in two ways:The size, diversity and multiplicity of mineral finds in the region, and the continuing prospectivity.The approach being undertaken to accelerate development, increase the value generated for all stakeholders, and the value added in the region.

Jan 1, 1993

The international scientific and engineer-ing community is being challenged to take advantage of the opportunity offered by the U.N. International Decade for Natural Disaster Reduction (IDNDR) program to reduce rapid onset geological hazards along the Pacific Rim. Natural disasters observe no national boundaries; international cooperation offers the best opportunity to reduce the losses these catastrophic events create.

Jan 1, 1990

By J M. Wang, Q M. Hao

A mathematical model is set up to solve the problem of optimal design of the production scheduling on exacting open pit mine. At the same time, the establishment of model in operation condition and its solution are considered completely. It gives not only algorithm of optimal design but also strict mathematical argumentation in the process of optimal design.

Jan 1, 2003

World class ore deposits can be defined commercially as deposits which contain metal concentrations in the upper quartile of resources size and/or grade, world wide, from which economic extraction can be undertaken, over a production period exceeding ten years, at a cost below the weighted average cost of cumulative production of the contained principal commodity of mines world wide.

Jan 1, 1993

Mining of the silver-lead-zinc orebodies at the George Fisher Mine officially started in 2000. A review of mining performance to date shows that many of the extracted primary stopes have experienced some degree of hangingwall dilution. The degree of hangingwall failure in the stopes became progressively more extensive throughout mining of the orebodies in 2001 and 2002, culminating in the unplanned catastrophic failure of the 744D stope in which the ore between 13C (2683RL) and 12L (2714RL) sublevels caved into the previously mined cavity between 13L (2654RL) and 13C sublevels. This was followed several months later by another unplanned caving event in a nearby stope, 740D. As a direct result of these unplanned failures it was decided to mine the stopes with a smaller span than had been previously planned and in a primary-secondary pyramidal stoping sequence. To limit the exposure of the stope hangingwall, a hangingwall drive is no longer developed and therefore geologists no longer have access to the detailed geological information that this provided. Geologists at George Fisher Mine have had to be adaptable and flexible in response to these proposed changes and rely more on data from drilling than mapping for their geological interpretation. The result is that the drilling cycle has become much more critical in the planning process.

Jan 1, 2003

By S Wasi, J Tobiczyk, J Roszkowski

Methane and fire hazards have a vital effect on work safety and continuity of mining plant operation. In the 1990s, the SMP hazards monitoring and ventilation control systems, based on continuous measurement of air parameters, were put into operation at nearly 30 Polish mines. These systems provide continuous measurement of methane concentration within the range of zero to 100 per cent with automatic switching off of electrical energy immediately after detection of potentially explosive conditions. Early detection of coal spontaneous combustion and open fires is made by continuous measurements of CO, CO2, smoke and O2 content in mine air as well as temperature changes in air and rock mass. The essence of the system is intrinsic safety of all underground instrumentation and uninterrupted central power supply from the surface. All abnormal and critical states are signalled to the mine control room. These trigger alarm and emergency procedures. The computer based ventilation monitoring and control system also performs the function of an expert system for fire detection and underground fire fighting. The mine control operator (dispatcher) makes use of stored data in computer escape route schemes and procedures for the safe withdrawal of miners from hazardous areas. The operator can put in motion intrinsically safe alarm signalling units and banners with programmed messages indicating escape routes.

Jan 1, 2005

By M Lewis, A Cook

This paper is based on the technology and functionality of a Modular Mining IntelliMINE« system which is a real-time decision-making tool. The IntelliMINE« system, incorporating Dispatch, is a fully Integrated Mine Management System. Measuring, quantifying and analysing the performance of mining is considered a fundamental and strategic step towards changing the nature of technical and operational decision-making at the majority of international mining corporations. Successful implementation of electronic data capture devices and computerised tools have enabled many mining operations to improve their competitive position with an improvement in the utilisation of the key assets, mineral resources, capital mining equipment and human resources. Real Time Mine Management Systems are designed to direct the emphasis away from collecting data and focus decision makers on the real issues with well-presented and reliable information. The systems provide a common stream of information to enable senior management, operations, maintenance, technical and process plant staff to make complementary decisions based on reliable, accurate and timely data. The mine asset information tools focus all employees on performance and give them feedback on their area of responsibility. The resulting tangible benefits can be delivered in different forms depending on the mining method, ore type, workplace culture and the current competitive position. Typical areas of improvement reported by system users are:reduction in capital expenditure on mining equipment fleets; more effective planning and budgeting parameters and procedures; increased control over ore-extraction and processing; increased employee accountability and organisational performance; and improved co-ordination between planning, operations, maintenance and processing. These improvements can be delivered in different forms depending on the status of the mine and commodity markets. In times of market oversupply and low commodity prices, the benefits can be delivered to the bottom line in terms of reduced cash costs, reduced capital and operating resources to maintain constant production. In times of market expansion, existing capital resources will be more productive delivering increased production and revenue. Mine management systems have the potential to transform a traditional mine operation into a learning organisation with an improved understanding of the critical performance issues and enable development of relevant strategies to continually identify and eliminate operational inefficiencies. The effectiveness of each strategy and operational change can be accurately monitored and its success (or otherwise) will be quantified. The latest downturn in the world metal prices has forced many mining companies to focus on cost reduction and productivity improvements as a means of remaining competitive. Maintenance represents a significant proportion of the overall operating costs in the mining industry. A structured proactive maintenance approach such as Reliability Centered Maintenance (RCM) can achieve significant cost reductions and productivity improvements. Remote condition monitoring systems are becoming increasingly commonplace and have the potential to identify problems prior to failure. Detection of equipment degradation prior to failure will enable repairs to be scheduled, thereby reducing costs and interruptions to production.

Jan 1, 2000