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By BLAKE DAWSON WALDRON

I must acknowledge my strategic adviser, Mr Lance Grimstone, who contributed to the development of this paper, and collated the text and figures.

Jan 1, 1994

The words ""Uncertainty"" and ""Risk"" pervade every discussion about mining exploration and investment. Perhaps these terms are subjectively understood by industry professionals, but objective portrayal of these concepts outside the industry is a woefully undeveloped science. This paper addresses current industry understanding and practice regarding quantitative risk assessment techniques, and provides examples of the application of three of these techniques. Probabilistic techniques for financial risk assessment are valuable adjuncts to conventional financial analysis, and address a range of issues not assessable by any other means. The value of whole-of-project probabilistic risk assessment is currently debatable for decision-making purposes, but is seen as important as a mechanism to focus attention to the critical issues that ultimately impact on project success. The dissection of project capital into risk and non-risk components provides valuable insights into risk characteristics not readily quantifiable in any other way. This technique also provides a framework for more objective ""what if?"" scenario evaluation and for the capital structure of resource projects. Finally, mechanisms for the valuation of undeveloped reserves are examined, and guidelines suggested. The importance of reliability in production cost estimates is highlighted and the impact of early development on reserve valuations is discussed. The importance of economics throughout all stages of the evaluation process is fundamental.

Jan 1, 1994

By C Riley, N Davies, J Carpenter, I Lipton

Nautilus Minerals Incorporated (Nautilus) recently announced the worldÆs first Seafloor Massive Sulfide Mineral Resource at Solwara 1 in the Bismarck Sea, Papua New Guinea . The discovery, exploration and resource modelling of this æblack smokerÆ system located 1500 m under the sea involved unique technological development. Whilst the resource estimation methodology had similarities with approaches adopted for analogous volcanic-hosted massive sulfide (VHMS) deposits, specific parts of the resource estimate called for new ways of assessing data. This paper discusses several innovative methods for collecting and assessing Solwara 1 exploration data. This ia an ABSTRACT only. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By G M. Mudd

Mine tailings represent one of the two largest sources of mine waste from the minerals industries (the other being waste rock). Given the problems of declining ore grades and growing production, tailings generation is increasing exponentially across the global mining industry. Common practice is for mines to build large containment dams to store tailings during operations, which are then rehabilitated following mine closure. At some sites, however, the controversial practices of riverine or marine dumping of tailings is still practiced. As recent tailings dam failures have shown, there are legitimate questions being raised about the long-term viability of leaving tailings above ground due to the risks of collapse and failure. At present, it is rare for mines to emplace tailings back into former mine voids following mine closure, most commonly into a former open pit mine void (although a fraction of the tailings may be used for underground mine backfill, this is minor in scale). The approach of in-pit tailings has numerous advantages, such as inherent physical stability, low to negligible acid and metalliferous drainage (AMD) risks, as well as allowing more productive use of formerly mined land. In tropical areas where surface repositories are prone to leakage with potential for AMD and widespread dispersal of radionuclides (in the case of uranium mining), in-pit management provides particularly strong advantages – thorough hydrogeological studies are required, however, to address residual groundwater contamination risks and to establish sound, long-term environmental monitoring regimes for groundwater quality and subsidence issues. This paper presents a study of in-pit tailings management and compares it with surface repositories established in a tropical climate. The comparisons lead to the conclusion that, at least under tropical conditions, in-pit tailings management should be considered as world’s best practice – especially for radioactive uranium tailings.

Aug 8, 2011

Design and construction techniques used to develop two highway tunnels in inaccessible mountainous terrain are described. Measures used to adapt the design to the unusual geology and topography are discussed, as well as measures to adapt the construction methods to available equipment, materials, and skills. Sharp local variations in geoloqic conditions resulted in field modifications to both design and construction techniques. The geology is a volcanic ash and breccia-agglomerate at one site, a jointed andesite at the other, which is also the site of a major landslide. Both rock reinforcement in the form of pretensioned and grouted rock bolts with a shotcrete lining,and rock support by struc- tural steel sets with a reinforced concrete lining were used. A canyonside location and high lateral in-situ stresses required modification of design procedures. Pilot tunnels at both sites resulted in adapting the designs to site conditions with large savings in lining costs, disclosing problem areas in advance of the main excavation, and cushioning of blasting pressure to minimize stability problems.

Jan 1, 1976

A practical approach has been developed for the design of both grates and pulp lifters. It is based on: an appreciation of the process interaction between grates and pulp lifters, an interpretation of mill charge structure as it relates to discharge through grates, and an analysis of pulp and solids flow in pulp lifter channels. This approach can be used to improve the overall discharge effectiveness of AG and SAG mills.

Jan 1, 2000

This study begins with the semivario- gram modelling of variables rutile grade and clay content from a beach sand rutile deposit. This is followed by two dimensional block kriging. The deposit was divided into blocks of 30 x 30 x 1.5 m dimensions and the kriged estimate together with the associated kriging variances for each variable within each block were determined. Finally, using the results of the krig- ing program and considering the acceptable limit of clay content together with the cutoff grade for rutile, a method for optimization of mineable thickness and hence the tonnage of ore was applied and the results were dis- Cussed.

Jan 1, 1986

The mining industry is quite often faced with declining selling prices for its products in the face of rising prices for the input cost resources that it uses. Blasting is a key activity within the mining system and has a vital role to play within the Mine to MillTM concept. It is therefore important that blasting makes a positive contribution to mine profit and productivity. There are several variables involved in considering the profitability and productivity of blasting. The rock types and structures, the bench height, the blast hole drill rig specifications, hole diameter, spacing and burden, explosive loading and initiation and blast size fragmentation. Productivity accounting is a methodology which is used elsewhere to give additional insights into the productivity and pricing factors that drive the financial performance of a business. Miners know intuitively that productivity and pricing influence costs and profit, but only with productivity accounting can the dollars involved be calculated. Drilling and blasting are part of a chain of unit operations in a mine. For an owner-miner, drilling and blasting would be considered as cost centres and a productivity accounting cost model approach would be relevant. On the other hand a contractor is likely to consider drilling and blasting as a profit centre, in which case a productivity accounting profit model approach would be appropriate. Both of these will be explained. The paper provides a basic outline of deterministic productivity accounting and demonstrates its application to blasting. Drilling and blasting data from a mine was obtained for a two-month period. The change in productivity and prices was calculated to obtain the dollar contributions from them towards the change in cost. It was determined that although there had been productivity dollar gains these were offset by larger pricing dollar losses, the net effect being that total drilling and blasting costs increased. The productivity accounting analysis gives the facts and the mine is in a position to establish priorities based on knowing the dollar contributions of each input used.

Jan 1, 2001

Plant growth is likely to prove the most suitable and satisfactory material to stabilise and cover quarry faces and worked-out surface mining sites. The careful selection of plant species is of paramount importance to the success of any attempts to re- vegetate these sites. Various tech- niques are recommended and attention is drawn to different factors,which will adversely affect plant growth.

Jan 1, 1976

By M Mee, R L. Gwyther

Accurate measurement of rock mass response during the mining of massive underground orebodies is essential, as mines become larger and deeper. These measurements enable: provision of quantitative data for optimal pit slope design and engineering; monitoring of the stability of deep pit slopes, the long-term integrity of shafts and large-scale underground infrastructure, and long-term measurements of deformation or rock mass creep following the mining process for environmental management. Strainmeters traditionally used for deformation measurement have neither the long-term stability nor the high sensitivity to perform measurements in these applications. This paper describes a new precision borehole strain monitoring system (GTS) currently deployed by CSIRO Exploration and Mining, which has the potential to solve these new issues in rock mass deformation monitoring. This technology was originally developed for use in hard rock mines (Gladwin, 1977) and refined considerably for earthquake research (Gladwin et al, 1994; Gwyther et al, 1992). A case study of the use of the GTS in monitoring longwall coal mining over the period 1993 - 1998 is presented.

Jan 1, 2000

By C L Humphrey

Biological monitoring programs for environmental protection require techniques that will provide both early detection of possible adverse effects, and assessment of the ecological significance of these effects. Monitoring techniques must include responses sensitive to the impact, that can be subjected to rigorous statistical analysis and for which statistical power is high. Such issues in baseline research of 'what and how to measure?' and 'for how long?' have been the focus of a program being developed to monitor and assess effects of mining operations on the effectively pristine, freshwater ecosystems of the Alligator Rivers Region (ARR) in tropical northern Australia. Application of the BACIP design, utilising a form of temporal replication, to univariate data (single species) and multivariate (community) data is described. For new ventures in Australia (such as mining), monitoring programs should be designed to establish with high probability that an impact on the ecosystem no greater than a prescribed amount has gone undetected - as opposed to simply allowing development to continue as long as 'proof' of impact is not available. Such a precautionary approach represents a shifting of the 'burden of proof' and would require with the BACIP design, a minimum number of baseline years in order to achieve some desired level of statistical power in a test for impact. Power analyses conducted on two to five years (depending upon the technique) of baseline data from streams of the ARR indicate that the BACIP design would not impose developmental constraints on mining and that a policy of reversal of the burden of proof would provide the cornerstone required for managing such development in an ecologically sustainable manner.

Jan 1, 1994

By Hawes GW

Until 1980 copper, lead and zinc sulphide slurries have been success- fully dewatered for rail and sea transport for many years at the Rose- bery site of North Broken Hill Holdings Ltd. utilizing conventional vacuum disc filtration systems. An upgrading and mill expansion program completed in 1981, which also permitted the introduction of ore streams changes, had resulted in difficulties dewatering copper and lead sulphide slurries to comply with transportable moisture limits. Following an extensive investigation which included both laboratory and pilot plant testing a program was commenced to replace the 2 vacuum disc filtration systems with 2 pressure filtration systems for use on copper and lead slurry dewatering and also to retain other existing vacuum disc filters as standby. An analysis of mill operations performance resulted in slurry storage tanks with a capacity equivalent to 20 hours of normal production being incorporated into the project. The pressure filters are mounted above the concentrate stock- piles. A sealed sloping floor incorporating launders is used to prevent any accidental contamination of the concentrate from pipe leakages, spillage, or from water hoses used for clean up purposes around the area. The project was completed in 1985 and operating performance has been better than that predicted from testwork. Equipment availability at 95076 together with the slurry storage capacity provided results in minimal requirement for the standby vacuum filtration system. Some typical operating results are given.

Jan 1, 1988

The intent of this address is to look forward into the 21st Century and present certain thoughts as to how underground coal mining might be conducted. The views in this talk are based principally on the author's experience with mining practices in the United States. It may be difficult to accept, but the 21st Century is a mere 12 years away. What new techniques will be available? To develop an understanding of the way in which technology has been and could be changing, a two- stage analysis is made of mining technology for U.S. Coal. The first phase covers the period 1975 to the present, while the second includes 1960 to 1975. This historical perspective includes a view of underground production by mining methods, considerations of labour productivity, and a review of accident and fatality rates. Several topics are important features of this historical analysis. Among the most significant are: (1) the introduction of Ion-wall mining technology into U.S. underground coal mines, (2) the use of computers to assist in mine planning and design activities, (3) major efforts to improve health and safety performance, with emphasis on underground dust control, and (4) improvements in mining equipment with an eye towards increased reliability and up-time performance. Based on that historical perspective, projections are made in three increments. The first being immediately at the turn of the century, the second being a dozen or so years beyond that, and the third being at the quarter point of the 21st Century.

Jan 1, 1988

By J Col, D La Rosa, W Valery, A Jankovic

Metso Minerals Process Technology Asia-Pacific and South America (MMPT) has been working with operations around the world to increase their efficiency through æMine-to-MillÆ or Process Integration and Optimisation (PIO) projects. These projects have delivered significant improvements in mine efficiency, mill throughput and reduced operating costs at mines around the world. The MMPT methodology involves rock characterisation, site auditing, data collection, modelling/simulation and implementation of integrated operating and control strategies on site. This results in significant benefits to the operations û for example, 5 to 20 per cent increases in concentrator throughput have been measured. MMPTÆs rock characterisation utilises simple and inexpensive measurements that can be performed by trained site personnel. The advantage of these measurements is that a large amount of data can be collected in a very short timeframe, as the samples do not require shipping to an outside laboratory. Typically, a PIO project starts with a site visit to perform blasting and process audits, collect high quality data including measurements of run-of-mine fragmentation and survey data around all crushing and grinding circuits. These measurements are combined with rock characterisation and the definition of strength and structure domains to model the complete production chain. Site-specific models of the blast fragmentation, crushing, grinding and flotation processes can then be developed. This proven methodology has applications ranging from greenfield projects to long-standing operations with AG/SAG or conventional grinding circuits. Process improvements can be higher mining productivity, higher mill throughput, decreased overall operating costs and higher flotation or leach recovery. This paper discusses a recent application of PIO conducted at a large open pit operation in South America and emphasises the potential that every operation has to ædo more with what they haveÆ.

Jan 1, 2007

The Gj0vik Olympic Mountain Hall is the world's largest underground cavern for public use and was created primarily to facilitate the ice hockey tournaments for the 1994 winter Olympics in Norway. The cavern has a span of 61 m, is 91 m long and is 25 m high. Ordinarily, rock caverns have a span width of 15 to 25 m, however, temporary mining caverns of up to 60 m have been excavated and natural caves with even greater dimensions occur. The Gj0vik Olympic Mountain Hall is unique as it is for public use with a capacity for 5800 spectators. Blasting was conducted with a high production rate at normal costs due to detailed planning and strict supervision of each round. The initiation system and vibration monitors were the main tools to control vibration levels and to facilitate a high production rate. It was of utmost importance that the rock remaining in the roofs and walls was of high quality after blasting to avoid rock fall, rock slides and excessive maintenance work.

Jan 1, 1995

By Gray E, Banks J

In mine site revegetation, exotic grasses are more commonly used than native grasses. This is due to unavailability of native grass seed on a commerical scale and lack of information on agronomical aspects of native grasses. This paper lists a number of native grass species that have the potential to grow well on mine sites, and provides some information on their seed collection, processing and germination. Further, it demonstrates via results of a field trial conducted at Ranger Mine spoil the relative performance of ten native grasses and Rhodes grass. It is concluded that (i) some native grasses have similar ability to grow on mine spoils compared to Rhodes grass and (ii) the use of native grasses have added advantages in ecosystem restoration.

Jan 1, 1994

By P Audet, D R. Mulligan, D Doley

This analysis attempts to reconcile existing ecological theories, rehabilitation planning goals and implementation constraints in the form of a rehabilitation paradigm that considers potential and pragmatic ecosystem transformation pathways. The framework prioritises multiple developmental scenarios for post-disturbed landscapes within a continuum of ecological outcomes. A feature of the framework is that ænovelÆ ecosystems and agro-ecosystems, having a range of commercial and societal values, are valid outcomes spanning the conceptual divide between the ecological functions of under-rehabilitated versus re-instated ænaturalÆ landscapes, especially in a changing environment. Landscape suitability analyses are considered to be fundamental to the incorporation of regional landscape and climate in the implementation of land rehabilitation and management strategies. Altogether, the paradigm could facilitate the identification of widely pertinent rehabilitation goals having direct implications at the regional scale of restoration ecology and acceptance of the need for ongoing commitment to the management of disturbed environments.CITATION:Audet, P, Doley, D and Mulligan, D R, 2012. Can ænovelÆ ecosystems offer suitable rehabilitation alternatives for post-mined landscapes?, in Proceedings Life-of-Mine 2012 , pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

A brief history of the significant haulage truck feature changes and the factors that influenced those changes during the 60's and 70's provide a basis for forecasting the changes that can be expected in the 1980's. A review of the impact factors and changing requirements that currently exist that will create changes. Define the critical requirements of a successful haulage truck design and discuss the availability of bigger engines and better electric drive componetry to provide deeper pit capability and improve reliability. The Unit Rig Trolley Assist System to provide improved productivity and diesel fuel savings and an economic analysis to evaluate the Trolley System is covered. The Unit Rig Automatic Truck System for a driverless truck is covered in concept and discussed from the point of view of the experience in a test in a New Mexico mine. INTRODUCTION A good basis for trying to forecast what is going to happen in the future is to go back a little bit in history, to see what the influencing elements were in different periods of time as a foundation for the forecast. INFLUENTIAL FACTORS IN THE 1960'S If you look at the truck development that occurred in the 1960's, there were some identifiable factors that give us insight. (See Fig. 1) Several things happened at the beginning of the 1960's. Mechanical drive haulage trucks were introduced that were

Jan 1, 1982

By B Muller

The disposal of tailings has become a greater issue due to the changing economics of mineral extraction. The processing of lower grade deposits and tougher environmental regulations has led to the selection process for tailings disposal options becoming more complicated. Current selection methods are too time consuming or too easily manipulated for inexperienced users to use successfully. This paper examines a different method for the initial selection of a tailings disposal system, using a numerical system that was introduced into the mining method selection field. The numerical method system was compiled by reviewing previous work done on the positive and negative aspects of the tailings disposal methods used by the coal and metallurgical mining industries. Assessing the common trends and design aspects of each of the methods was undertaken and a ranking was designed to explain how well suited the tailings disposal methods are to a situation. The tool successfully analysed sites using common data to indicate methods for disposal that would have provided minimal technical problems, low environmental risk and been practically possible. The tool also proved successful in identifying critical areas that would need further investigation. This new system was tested on some disaster case studies from around the world in order to show that it could have successfully selected a different method for tailings disposal that would have prevented the disaster.

Sep 26, 2011

By Miller D. R

The mineral exploration and extraction industries have gained major cost and efficiency benefits from the use of computers. However these industries are now at a cross-roads with two seemingly disparate developments - that of an increasing number of complex geoscience databases and, at the same time, the merging of all known data for the particular regions at minimal cost. These two developments can be managed by the development and of an industry accepted geoscience data model and dictionary. This will provide a common basis of understanding for geoscience data through a common language and a common structure for geoscience information. Integration of specialist systems and databases can then proceed efficiently. The development of a data model is going ahead with consensus from the mining industry. This is a joint government and industry funded project and managed through the Australian Mineral Industries Research Association, AMIRA. AMIRA is a well known research broker to the Australian mining industry obtaining sponsorship for projects both from private and government groups. The AMIRA project, P431, called the Geoscience Data Model, is to be the Australian standard data model for geoscience disciplines. The requirement for a standard geoscience data model has been recognised in Australia for some time. In October 1991, the Australian Government Geoscience Database Policy Advisory Committee (GGDPAC) established a Geoscience Data Standards Working Group which drafted a comprehensive list of data categories of the geoscience area. An AMIRA project called AMDEX was established to develop a transfer standard for the mining industry data at about the same time as this committee was in operation. The first AMDEX sponsors meeting was held in May 1991. It was proposed to use the US Spatial Data Transfer Standard (SDTS) as the basis to transfer mining data in AMDEX. A limited data model of mining data to be transferred was developed for the AMDEX standard under SDTS. The Australian Geological Survey Organisation (AGSO) saw the need to extend this and develop a complete data model for the geosciences and proposed this as a new project to AMIRA. This was strongly supported by GGDPAC which lead to sponsorship of the project from most state geological surveys. The Geoscience Data Model can be broken down into separate data models for a number of geoscience themes and sponsorship obtained so far will enable models to be developed for a comprehensive set of themes selected by the project sponsors. Further sponsorship is required to enable a more complete coverage of the geoscience area to be developed. Sponsorship for the Geoscience Data Model has been strong from the geological surveys and there was some effort by GGDPAC to promote the project in these organisations. An Australian geoscience data model is of immediate use to the geological surveys in assisting the standardising of huge quantities of geoscience data held by government agencies and it is preferable that this be an Australia-wide standard.

Jan 1, 1995