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The Pilbara iron ore industry has seen rapid growth over the last five years and is now bracing itself for another expansion which will take its seaborne trade to beyond 500 Mt/a. To effectively utilise port capacities, port stockpile turnover will become extremely rapid and each stockpile built will have to be of a quality which is precise and unbiased.Sampling systems at the older Pilbara mine sites were generally designed during the 1980s and reflect the practices which were considered adequate at the time. Hence, the precision of measurement at production sites is generally unknown and quality assurance (QA) of sampling facilities falls short of what current best practice suggests. This paper suggests practical improvements in sampling practices and quality assurance, which will assist the industry in achieving quality objectives in times of rapid mining expansion.

Jan 1, 2008

By Tyson G. R

A novel system has been developed using computer imaging techniques to make on-line measurements of material on a moving conveyor. Meas- urements of the mass or volume of conveyor materials are important in large open pit mining operations such as those operated by the State Elec- tricity Commission of Victoria (SECV). Such on-line measurements can be used for monitoring and controlling the production and transport of coal or overburden, and to assist in maintaining production levels. This paper describes a conveyor burden volume measurement system which is currently under development at the Research and Development Department of the SECV and although targeted initially for use in the Commission's open cut mines, the system is suitable for use on any open conveyor system. A basic developmental system has been built to demon- strate the viability of the technique used and further work on the system is planned. The measurement technique and the major components which have been developed as part of the system are described, some comparisons are drawn with other existing measurement systems and potential errors and future development are discussed.

Jan 1, 1989

By D Giles

We present plate tectonic reconstructions, showing that porphyry-type ore deposits are spatially and temporally linked to ridge subduction. A reconstruction of the Peruvian subduction system reveals an immediate metallogenic response to the arrival of the Nazca Ridge at the subduction trench, followed by southward migration of the zone of metallogenic activity due to the lateral migration of the zone of ridge subduction. A similar pattern is recognised in central Chile , where the spatio-temporal distribution of giant ore deposits coincides with the arrival of the Juan Fernandez hotspot chain at the subduction zone. We conclude that there is a spatial and temporal link between ridge subduction and ore deposit formation, with high metal fluxes concentrated in zones of ridge subduction. Thus, the recognition of tectonic patterns associated with ridge subduction can provide insights into predictive mineral discovery by enhancing our ability to predict the position of large mineral deposits in other modern and ancient orogens. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

The decision to contract or owner mine should be independent of, and should be made before, definitive estimated cost comparisons could be available. There is substantial potential risk of estimated cost comparisons being flawed due to difficulties in compiling comparable estimates for differing business objectives, errors and omissions or because of significant bias. In the current economic environment, escalating cost pressures potentially lead to increased incidence of disputes in mining contracts. The apparent cost of contractorÆs profit and overheads has tended to become more significant to owners. Economy-driven trends towards higher levels of performance and commercial risk for contractors, and the potential for more adversarial, difficult management; with attendant disputation between contractors and owners, have encouraged development of so-called ærelationship contractsÆ û partnering or project alliance contracts. The paper discusses the issues, circumstances when owner mining or contract mining is favoured and perceived advantages and disadvantages of contract mining. The implications of owner-perceived core business and core skills and outsourcing are also discussed. Techniques of introducing objectivity into the decision to owner or contract mine using matrix analysis or benefit comparisons are described. A disciplined procurement process should deliver a decision to owner or contract mine independent of, and prior to, any definitive comparison of estimated costs. A generic procurement process model is provided as a basis for discussion. Risk is discussed generally and as a significant factor in comparison of estimated operating costs. Consideration of risk and any prudent cost treatment are promoted as necessary pre-requisites to any comparison of estimated costs. The paper develops the concept that the decision to owner or contract mine should be based on real benefits that become obvious in the early stages of the development, particularly the procurement process; and before definitive estimated cost comparison can be available. In the context of this concept estimated cost comparisons tend to be confirmatory. Problems with comparing estimated ownerÆs operating costs with tendered contract prices are also discussed, particularly recovery of capital cost of equipment; and the owner minerÆs trade-off of operating risks for the residual contractorÆs margin attributed to overheads and profit. The paper concludes that sole reliance on a comparison of estimated ownerÆs operating costs with tendered contract prices in deciding to owner or contract mine is questionable and likely driven by a need to satisfy specific in-house customers.

Jan 1, 2003

By H Kurth

Oyu Tolgoi copper and gold mine in the southern Mongolia holds mineral resources that make it one of the largest known copper and gold deposits in the world. The project is operating an open pit mine on the near surface of Southern Oyu deposit and developing underground block-caving mine at the Hugo Dummet North where 80 per cent of total resources exists. Oyu Tolgoi (OT) commenced open pit mining in 2011 and implemented an industry standard blasthole sampling, and ordinary kriging grade control estimation with block-out process. Since 2017, grade control improvement projects have successfully completed that have led to the implementation of current, improved grade control system. Geological model is updated by blasthole logging on Leapfrog® and used for daily grade estimations. GC estimation is proceeded solely on Vulcan® by running Lava script and integrating with a relational database. Combination of block-out procedure produces GC model which is updated in Vulcan® and as well as in the database simultaneously. Switching to the integrated database eliminated many manual processes such as importing and exporting data and enabled access to the database anytime, anywhere and from any device. Thereby, these improvements allowed to increase an efficiency, create a comprehensive reconciliation system and reduce operational risks. We are looking forward to expanding applications of integrated grade control data stored in the database. This paper outlines how the grade control system was developed at OT’s open pit mine, and how it is integrated into the short range mine planning, mine reconciliation workflow and ultimately enabled development of various automated reporting systems.

Mar 22, 2022

The Broken Hill (BH) Block contains a wide variety of mineralization, with comrodities including Pb, Ag, Zn, W, Cu, Co and Sn. Much of the mineralization is stratigraphically controlled. Fe, Cu and Co-rich mineralization is dcminant in the Thackaringa Group; Pb, Ag, Zn and W is dcminant in the BH Group and Sn mineralization is present above the BH Group. Some mineralization occurs as concordant syngenetic deposits, but other types have been partly or completely remobilized by metamorphism, magmatic activity or hydrothermal fluids. Almost all of the non-syngenetic mineralization, including stratabound, vein and intrusive-related types, has formed from the "recycling" (remobilization and redeposition) of metals originally deposited with the sediments and volcanics of the Willyama Supergroup.

Jan 1, 1983

The south-east Missouri cobalt-copper-lead-zinc district is the worldÆs largest lead producer and a significant producer of by-product zinc, copper, cobalt, silver and cadmium. Current production in the district comes from six or seven mines in the Viburnum Trend. Most ores in the Viburnum Trend are characterised by a small number of minerals with simple compositions. Portions of some orebodies contain ores that exhibit greater variations in mineralogy, and these include shale-hosted lead- copper ores, bornite ores and nickel-arsenic sulfide ores. Ore textures include both replacement and open space filling textures, and the paragenetic sequence for the ores is characterised by repetitive periods of deposition of all of the ore and gangue minerals. Ore microscopy is an effective tool for not only the identification of the minerals and textures shown by the ores, but also to determine the mineralogy and textures responsible for beneficiation problems. An interesting variety of sedimentary and structural ore controls have determined the locations of individual orebodies in the district. Based upon the positions of orebodies with respect to Precambrian ridges and knobs, together with areal patterns of mineral/metal zoning, it is interpreted that the ore fluids came from diverse directions to form the deposits in the district. It is concluded that the Old Lead Belt subdistrict was mineralised by fluids that flowed from the north-east and north-west, the Fredericktown area by fluids from the north-east, the Indian Creek subdistrict by fluids from the north-west and the Viburnum Trend by fluids from the north-west and west.

Jan 1, 2008

IT is intended herein: to make some brief comments on geophysical 'work in general and on the various methods, and then to refer to that branch which, perhaps, is of the greatest importance and interest to the metalliferous mining engineer, i.e., the variousmethods of electrical prospecting.The term geophysics was originally applied to those larger physical and geodetic studies and methods concerned with such purely scientific subjects as the investigation of the true figure of the earth and the determination of the stability relations resultingtherefrom. Applied geophysics and geophysical methods of prospecting are concerned primarily with the search for, and investigation of, useful mineral deposits concealed within the earth's crust and not readily detectable by the normal methods employed bythe mining geologist and prospector. The methods employed have been devised as a result of co-operation between mining men, geologists, and physicists, and, although steady progress has been made during the past 20 years or so, it is within the last four orfive years that the importance of these methods has been acknowledged by the mining world in general. Although many of these methods are still in, or have barely emerged from, the experimental stages, a steadily increasing list of important discoveries is attributable to their employment-more particularly in Europe and America than elsewhere. The various methods have each their own limitations regarding the class of work they can undertake, and no one method is capable of general application. The greatest care should be exercised in selecting the method, or methods, to be employed in any particular area, the...

Jan 1, 1928

By B Tadesse, L G. Dyer, K Ward

The Golden Mile ore deposit in Western Australia is one of the largest gold telluride deposits in the world. Approximately 20 per cent of the contained gold in the deposit is present as gold telluride minerals, the most prevalent being calaverite (AuTe2) and petzite (Ag3AuTe2). Telluride mineralogy in the Golden Mile orebody is fine grained and complex having formed due to hydrothermal deposition in the late paragenetic sequence. Nineteen tellurium bearing minerals have been identified including gold and silver as well as mercury, lead and nickel tellurides (Shackleton, Spry and Bateman, 2003). Extensive work has been completed on the flotation of gold, gold-silver alloys and gold ores however there is a lack of information detailing the difference between flotation of native gold and individual gold minerals (Dunne, 2016). Studies on the flotation behaviour of gold ores have focused primarily on the flotation of free gold and refractory sulfides (Teague, Van Deventer and Swaminathan, 1999).

Aug 24, 2022

By Baafi EY, MacKenzie -Wood P

An experienced and reliable knowledge of fire fighting procedures is necessary for mine emergency situations. Since experts in this area are scarce the technology of expert systems lends itself as a suitable component in the decision making process. This paper describes an expert system that is being developed for this purpose. The expert system. RESCUE. is a knowledge-based computer programme which incorporates the judgement, experience, rules of thumb. mine environmental conditions as well as human intuitions in the mine rescue operation. RESCUE makes decisions such as whether or not the affected area should be sealed.' whether or not rescuemen should be withdrawn, and which fire fighting agent is most appropriate for the situation. The IF..... THEN rules written in the VP-EXPERT shell contains antecedents and conclusions based on environmental as well as other conditions prevailing in the mine. For example, the CO/Oz deficiency ratio indicates the progress of heating; explosibility trends are given by varying flammable gases C CH4,H2,CO) in relation to oxygen concentration, and barometric pressure falls may affect explosibility by increasing CH4 content in workings. The interaction of such numeric-based rules with others rules reflecting the experience and judgement of the experts assist the system to arrive at its conclusions and subsequent course of action.

Jan 1, 1988

By G Kuntz, V Wall, B New

The prime aim of the Campbell Mine project was to develop a 3D geological model for the Campbell-Red Lake system to contribute to an exploration model for the region. The base data is composed of over 60 years of geological data covering an area of 16 by 8 km, and from surface down to 1830 m depth. This paper concentrates on the methods used in the GeoSpace system for the processing, integration, display and interpretation of such a large and diverse data set. A block model was developed that recorded the relative frequency of each geological feature within each block. The data input for the block models were based on recoding of the Campbell Mine drilling and channel sample databases into lithological, alteration and structural subsets. The value for each geological characteristic inserted into each block is calculated from all available data that falls within the block. Relative and absolute comparisons of the individual variables provide a targeted outcome from which the blocks are coloured for visual inspection. Different combinations of variable comparisons can be evaluated so that required features are highlighted for interpretation. Blocks are displayed to illuminate the ædominantÆ rock type, according to a formula that may be varied interactively to display the features required by the geologist. This flexibility allows rapid remodelling of lithological distributions, commonly highlighting minor lithological packages not readily visualised in, and interpreted from, drillhole traces alone. The 3D geological model was built from the drillhole datasets and old mine plans utilising standard 3D mining, GIS and database software, with several iterations of plan and sectional interpretation. Near surface bedrock geological interpretations were further constrained by low level aeromagnetic data. The Geospace approach employs an innovative technique for visualisation of the distribution of lithological packages and alteration via block modelling. The method utilises the block model format of data handling as it is considered to be more visible than drilling, flexible enough to incorporate a wide range of data sources, and allows for spatial proximity relationships to be investigated. The method is a simple form of processing large data sets so that results are clearly visible. The calculation is much more rapid than estimation procedures, and does not have any requirement for geostatistical interpretation which is also time consuming. Geospace is not unique to any mine environment software and it is expected to be able to be performed in any system. The proper portrayal of the internal structure of the mineralised body will provide practical input to exploration and mining principally in the areas of resource estimation, exploration vectoring and ore/waste characterisation and may be incorporated with other data to include mine support and mine scheduling.

Jan 1, 2003

By Hall S. F, Quast K. B Newell R, Ketteridge I. B

For the past six years research funded by the State Energy Research Advisory Commit- tee of South Australia has been conducted at the South Australian Institute of Technology, School of Mining and Metallurgy on South Australian lignites. A major part of this work has been a study of the potential bene- fication of Bowmans lignite using hydrometal- lurgical techniques. The Bowmans lignite de- posit is the largest of its type in South Australia and is a major energy reserve for the state. The utilization potential of this deposit is reduced by its very high insitu NaCl content which presents serious problems for any process. Previous research conducted by Readett and co-workers (1984a & b) has shown that NaCl is amenable to extraction using simple batch water leaching operations. This leaching has been successfully described using a two stage diffusion model derived from first principles based on a simple diaphragm cell.

Jan 1, 1987

By Mercer JK

This paper gives a description of the research undertaken by an explosives manufacturer to give better technical advice to the Mineral Industry. Blasting Physics is defined as giving a systematic and coherent account of the initiation and subsequent effects of high explosives upon the surrounding medium. As a result of this work a mathematical model based on the gener- ally accepted mechanism of blasting has been developed. The mechanism and the resulting model are briefly outlined. IFrom'this model the effects of burden, spacing, blasthole diameter, rock and explosive properties upon fragmentation and heave can be calculated. Using these calculations it is then possible to see how variations in frag Imentation and heave can affect the overall production costs of a mine whether it is surface or underground. The overall costs are made up of a number of individual costs - drilling, blasting, loading, hauling and crushing. ach of these operations influences or is influenced by fragmentation and heave s these costs are inter-related, the

Jan 1, 1975

By P Christen, D R. Ashley, G R. Power

The Ernest Henry Mine is currently a copper-gold open pit operation situated in north-west Queensland, Australia. It is owned and operated by Xstrata Copper with a current throughput of 11 million tonnes per annum; however, open pit operations are scheduled to cease in late 2011. The deposit dips at approximately 45¦ and extends for at least another 400 vertical metres below the final 530 m deep pit design. Resource drilling from 2002 until mid 2008 has enabled an Indicated Mineral Resource to be established to 1000 m below surface. Scoping and prefeasibility studies (PFS) have been completed toward determining if this resource is suitable for underground mining and a feasibility study is currently progressing with a sublevel caving (SLC) concept. This paper briefly describes the process by which the SLC method was selected, conclusions regarding the non-selected methods, and then discusses the optimisation process used to derive the mining plan. The key optimisation parameters include the production drive spacing, level spacing, draw strategy, cut-off grade and production rate. Key risks will then be assessed and economic sensitivities studied. Final sensitivities will use Monte Carlo simulations to improve the transparency of the projectÆs risk profile. The feasibility study (FS) began in March 2008 and this paper describes the main optimisation steps at the time of writing and outlines the plan for study completion through to March 2009.

Jan 1, 2009

By Taylor RN

A simple apparatus for delivering pulverized coal as fuel to a SIROSMELT lance is described, and its performance in smelting tests is evaluated. Using the pulverized coal as fuel, the SIROSMELT furnace performed well in both oxidative copper smelting and reductive smelting (zinc fuming). In both cases the evidence suggests that part of the combustion occurred by indirect oxidation of coal particles entrained in the bath. Oxygen potential measurements made during the zinc fuming tests confirmed the general features of the the non-equilibrium mechanism for zinc fuming proposed by Richards and Brimacombe. The zinc level in the slag during continuous fuming was lower than was predicted using an equilibrium model.

Jan 1, 1987

There are serious problems in forecast- ing accurately and achieving this goal depends on good quality information, correct assumpt- ions and sound analysis. planner. The forecaster must focus attention on a number of key areas of interest. These areas include major economic trends and changing GNP structure, consumption time series, end-use consumption patterns and substitution potential, accurately updating data bases (up to 5 years ahead), random factor estimation and examination of both long term and secondary mine potential. While metal price forecasting has suffered due to recent uncertainties, with increased importance on planning tools and cost analyses, it is still a necessary function. Forecasting is subject to the real world and the metal industry is made up of imperfect markets in a dynamic state. The real world provides the challenge to improve the accuracy of forecasting.

Jan 1, 1983

The Ladolam gold deposit, located on Lihir Island in PNG, is one of the largest known epithermal gold deposits, with a resource of over 37 million ounces. The deposit is characterised by a telescoped porphyry-epithermal system 2-rich sulphidic hydrothermal fluids capable of transporting significant quantities of gold, and the sudden change from porphyry to pithermal conditions caused by removal of the volcanic edifice. As magmatic ore fluids breached the surface, cool surface waters (seawater and/or meteoric) acted as a diluent. Although no other deposit is known with comparable geological characteristics and size, positive features that may be looked for in exploration for other like-deposits elsewhere include magnetite-rich alkalic volcanic rocks, large carbonate haloes, and presence of phreatomagmatic breccias. New discoveries may be recessive or undercover, due to the quartz-poor nature of the alteration.

Jan 1, 2002

Reverse circulation (R.C.) drilling or the dual tube method as it is quite commonly known, has a unique place in conventional mineral drilling. It can be classified half-way between open hole drilling at the lower end of the scale and diamond drilling at the upper end. The system basically consists of two tubes, one inside the other, with compressed air flowing between the inner and outer tubes. Sample cuttings return up the inner tube through the head of the rig and via a hose to a cyclone where the sample is collected. This system means that the cuttings are free of contamination as they are at no time in contact with the outside formation of the hole.Reverse circulation drilling is divided into two areas: R.C. Roller and Blade for softer formations; and R.C. Percussion for harder formations.

Jan 1, 1986

During the course of an investigation into the fundamental chemistry of the cyanide process, it became evident that the usual method of determining protective alkalinity was not completely satisfactory. T.he routine method for the determination of protective alkali by first removing free cyanide by the addition of silver nitrate, followed by titration of alkali with dilute acid using. phenolphthalein as indicator, can be shown to give correct results only when the alkali is a strong base. For other sUbstances, the alkali so determined is not the protective alkali. In view of the complications associated with the presence of zinc in cyanide solutions the discussion will be restricted in the first place to solutions free from zinc. Until the chemistry of simple cyanide solutions is placed on a quantitative basis it will be difficult to elucidate the behaviour of complex mill solutions.By the use of physico-chemical theory, it is possible to treat certain aspects of 'the chemistry of cyanide solutions in a manner which not only illustrates the important variables involved, but which also shows the need for care in interpretIng results obtained by conventional methods.In the following, comparatively simple systems are discussed; the principles established should be of use in interpreting the behaviour of more complex solutions. The methods described are not intended for routine work, but may be regarded as supplementary to the usual analysis carried out for the control of plant solutions, or as alternatives to be used when the latter do not appear to be satisfactory.

Jan 1, 1948

By Zamora C

The performance of a system for detecting the onset of overloads on rod mills is described. The system has bee,, tested at CODELCO E1 Salvador Concentrator where, due t,, variations on size distribution of the copper ore feed, th' rod mill is frequently subject to overloads. The main inpur signal to the system is the rod mill sound, after being measured and analog conditioned. This signal and othe signals measuring the fresh ore feed and the mill watt addition are fed to a computer containing a simpl mathematical model. The model parameters are empiricall estimated and an analog output signal is generated, whic gives an early prediction of the overload condition. The experimental results described in this paper show that the overload condition may be predicted with an anticipation of about three minutes.

Jan 1, 1985