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By Favreau RF

Over the last 20 years the blasting industry has progressed from the stage of being artform to a science as it is today. The use of computers to simulate blasting results has allowed blasting engineers to accurately pre- dict blast results and to optimise their blasting. This paper describes the computer blast simulator called BLASPA and its various applications in blasting. BLASPA allows the blasting engineer to predict blast results given known details of explosive properties, their distribution, rock type and properties, hole size, burden, spacing, collar and subdrill. The simulator runs mathematical situations and outputs numerical estimates of fragmentation and muckpile results. The paper discusses results which show that the mathematical outputs correlate very closely with actual results seen in the field, thus confirming the validity of the simulator. BLASPA can be used to help improve blast design by predicting stress levels in the rock mass and consequent rock breakage.

Jan 1, 1986

By Eupene GS

The Early Proterozioc Pine Creek Geosyncline hosts a large number of gold showings. Mineralisation types include stratiform, synsedimentary deposits within iron formation and carbonaceous mudstone; disseminations in granophyric intrusives; and quartz vein related concentrations in the form of shear fillings, saddle reefs and stockworks. Stratiform gold deposits preferentially formed near penecontemporareous faults during periods of basin instability. Intrusive basic magmas later assimilated some stratiform mineralisation and subsequently redeposited it within differentiated phases. Gold was again remobilized during regional deformation and metamorphism. Stratiform mineralisation was upgraded insitu in high strain zones and gold was mobilized into metamorphic fluids. Fluid induced fracturing during prograde metamorphism and later uplift caused the deposition of extensive gold rich vein systems. The genetic relationship between gold deposit types is reflected in the clustering of showings along regional anticlines, and provides a powerful exploration tool. The large volume of 'exhalative'òmaterial in the Geosyncline with elevated gold content suggests significant economic stratiform mineralisation may be present, and probably provides a source for later disseminated and vein deposits.

Jan 1, 1984

The Indonesian province of Papua is a remote jungle-clad region covering the western half of the mountainous island of New Guinea. Despite being relatively under-explored to this day,Papua is home to the greatest mineral success story of the 20th century. The Grasberg/Ertsberg minerals district atop the central dividing range contains the worldÆs largest reserve of both copper and gold (Freeport-McMoRan Copper and Gold, 2002). With large mines at Ok Tedi,Por gera and Lihir,and many well-delineated resources such as Frieda River,Wafi and Hidden Valley, neighbouring Papua New Guinea,the eastern half of New Guinea has enjoyed sustained exploration campaigns for gold and copper since the mid 1960s. The combined Grasberg and PNG exploration successes can be measured in terms of ounces of gold produced over the last decade versus available landmass,conf irming the island of New Guinea and surrounding islands as a world-class destination for gold explorers. Yet despite this obvious regional prospectivity and the profitability of the Grasberg operation, a sustained exploration effort in the Papua province in Indonesia has not been achieved. Periodic political constraints, poor infrastructure, high costs, operational challenges, social and environmental concerns and lack of immediate exploration success often impact exploration investment decisions. Accordingly a lesser number of mineral occurrences have been documented in Papua compared to those seen along tectonic strike in geologically similar Papua New Guinea.

Jan 1, 2004

By Erceg MM

The Waft River gold deposit is hosted by low grade metasediments which have been intruded by a dacite/andesite porphyry complex. Wafi River is classified as a high sulphur, epithermal type gold deposit having: a high sulphur content, a close association with calc-alkalic igneous rocks, zoned advanced argillic and argillic alteration, and enargite group minerals. Gold occurs as minute inclusions in pyrite and pyrrhotite within intermediate dickite/kaohnite - interlayered illitic clay alteration zones. Central leached silicic, alunite and pyrophyllite zones and peripheral chloritic zones are low in gold. The gold mineralisation at Wafi is interpreted to have been predominantly caused by mixing of hot upwelling acidic magmatic mineralised fluids with cool, neutral meteoric/hydrothermal fluids within permeable sediments. Locallised high grade breccia zones are encountered within the porphyry. An initial resource in excess of I million ounces Au has been defined.

Jan 1, 1990

By Ward C. W

Conventional polygonal and block modelling techniques inadequately represent the grade-thickness distribution of some narrow shear and stratabound gold deposits. The polygonal influence of high-grade drill intercepts can result in overestimates of resource tonnages at high-grade cut-offs. Although block modelling methods provide grade smoothing and a better representation of structural continuity, the technique can lack precise definition of ore width. An alternative method known as Spatial Object Modelling (SOM) has been developed on MineMap software to overcome some of these modelling issues. This method does not rely on a uniform cell size and allows grade smoothing between resource intercepts in three-dimensional space. The SOM technique creates grade-thickness bars on regular, user-defined spacings which allow easy visual comparison of raw intercept data to the interpolated model. Model cell values are readily transformed into isopachs, isopleths and resource perimeters for reporting and mine planning purposes.

Jan 1, 1997

By Neill A. O, Worth I, O&apos

The formation of Kalgoorlie Consolidated Gold \lincs 1't% Ltd hati pla,xd all the major the gold producing areas adjacent to the city of Kalgoorlie/Boulder under one management, enabling the development of the 'Super Pit'. This has facilitated the economic optimisation of the resource. Optimisation has been achieved by the timely collection and presentation of data and the use of these data to reduce costs and improve planning procedures.In particular the following issues have been addressed:ò the reduction of the impact of the mining activity on the adjacent urban population centre,ò implementation of safety procedures for mining through underground voids,ò the determination of the optimum bench height and mining method for ore production benches and blast design. This system is fundamentally based on maintaining a high degree of selectivity while achieving a balance of relatively low unit operating costs,ò assessment of the comparable benefits of contractor versus owner operated earth moving equipment, andò the development of effective ore body models, production reconciliation and the long term mine planning procedures to facilitate effective strategic planning.

Jan 1, 1993

Mssissippi Valley-type (MVT) and sedimentary-exhalative (SEDEX) zinc-lead deposits represent about half to three-quarters of the world's production and reserves of lead and zinc. The two deposit-types have traditionally been regarded as separate entities in terms of genesis largely because they possess very different morphologies, resulting from the epigenetic nature of MVT deposits and the syngenetic origin of SEDEX deposits. Similarities in regional setting, metal ratios, size and grade, lead and sulphur isotopes, and source(s) of fluids and metals in the two deposit-types, however, suggest that they could be products of similar genetic processes. The physical properties of MVT ore fluids suggest that certain types of SEDEX deposits could have been formed from fluids possessing similar salinities and temperatures. The hypothesis is further strengthened by the facts that: 1. in several cases MVT and SEDEX mineralisation occurs in the same region, and 2. recent advances in establishing the timing of MVT mineralisation has revealed that some MVT deposits are contemporaneous with nearby SEDEX deposits. If MVT and SEDEX zinc-lead deposits do indeed share a common ultimate derivation from fluids that emanated from sedimentary basins, then the presence of one deposit-type in a region could be used to infer the possible presence of undetected deposits of the other type. Furthermore, knowledge of the mineralisation age of one type will constrain the exploration target host rocks of the other type. A genetic relationship between MVT and SEDEX mineralisation may also explain why certain individual deposits, such as several in Ireland and eastern Canada, appear to be 'hybrids' and possess geological attributes of both end-member types.

Jan 1, 1993

By F Palkovitz, S Wilson, F Felipe

The management of waste from mining operations is a significant aspect of bringing a mineral commodity to final market. The ore beneficiation process and transport/disposal of waste involves significant consumption of costly resources. A number of options exist to dispose of mill waste on surface and as a backfill material. These range in complexity, risk, capital cost, operating cost and ultimately business performance. This paper discusses the value delivered to a business in using dewatering systems including paste as opposed to conventional slurry tailings disposals. This is illustrated through various case studies and serves to demonstrate how paste can add value and reduce risk to a successful business.

Jan 1, 2009

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007

By Woodcock J. T, Millett R. N

It was shown that manganese dioxide could be used as an oxidant in acid thiourea leaching of a gold ore. Manganese dioxide could generate high redox potentials and was as effective as hydrogen peroxide in the leaching process. Results obtained under closely controlled leaching conditions confirmed that high redox potentials enabled faster dissolution of gold to be obtained but led to extremely high reagent consumptions (thiourea, acid, and manganese dioxide). Additions of sodium sulphite solution in an attempt to lower thiourea consumption by reducing formamidine disulphide back to thiourea were only marginally successful. Although thio- urea consumption was slightly decreased, the consumption of acid and manganese dioxide was substantially increased and there was no net benefit in using sulphite. Tests in which a single addition of mangan- ese dioxide was made before addition of thiourea minimized overall reagent consumption and gave only a slightly lower dissolution rate of gold. This is a promising technique for further Investigation.

Jan 1, 1987

The application of reinforcement techniques to enhance the stability of underground coal mine roadways subject to high stresses is discussed. Research conducted in the Illawarra Coal Measures has been aimed to delineate the factors which influence the behaviour of rock above roadways and the performance of the reinforcement placed. Design considerations for the reinforcement of mine roadways in the Bulli coal are based on a quantification of the rock response together with a reinforcement strategy to enhance the structural integrity of the roof strata.

Jan 1, 1986

IN this paper the author's intention is to convey a brief resume of the lead flotation treatment and lead flotation machines, which have replaced the May jigs and Wilfley tables at the plant of the North Broken Hill Ltd., and converted this mill into an all-flotation plant.Attention is directed to the fact that this drastic change from semi-gravity to all-flotation treatment, has been successfully accomplished without resorting to finer grinding than that previously in vogue for Wilfley table concentration, viz.: 10% to 16% plus 40-mesh I.M.M. screen.From the figures now available it is manifest that the scheme of all-flotation concentration-new as regards its successful application to Broken Hill ores is resulting in considerably higher-grade lead concentrates, and is substantially decreasing charges for labour, stores, and maintenance.The new treatment is far-reaching in its simplification of plant, as evidenced by the idle jigs and tables, and the results being obtained by North Broken Hill Ltd. may possibly influence metallurgical practice generally in Broken Hill.The outstanding features of the treatment are:(1) The coarseness, and high grade of lead concentrates obtainable.(2) The low time factor required for flotation.(3) The plant capacity, and the simplicity of its operation.(4) The low horse-power consumption.(5) The small cost for reagents used (not exceeding 3d. per ton of ore).

Jan 1, 1930

By Fabjanczyk MW, Aziz NI, Hii J

The paper presents the results of a series of pull out tests performed on roof reinforcement systems currently being adopted in mines in Australia 7mm wire, dividag bar, 15.2mm strand cable, and birdcage cable. The study also investigated the load deformation chara- cteristics and the various design parameters controlling the effectiveness of a cable-grout system. Suggestions for continued work are Highlighted.

Jan 1, 1986

Deposition of uranium in the South Alligator river area has been influenced structurally by reverse faulting; and lithologically by carbonaceous shales and sandstones. Mineral assemblages suggest a mesothermal-epithermal epigenetic mode of origin. The ultimate source of the uranium and associated metals is probably in deep seated magmatism which is expressed at surface in the widespread penecontemporaneous vulcanity.

Jan 1, 1968

By Simpson JF, Murrie SJ

In determining new areas for slag disposal a foamed slag aggregate has been developed for use as a skid resistant material. The foaming of the slag does not rely on the use of water, but rather on the slag chemistry. Laboratory test results indicated that a product having good skid resistant properties has been prod- uced. A section of road is being assessed for performance of the aggregate in a surface dressing application under heavy load. The results from the test section after seven months have shown that the foamed slag is suitable for this application. Further test sections are now being considered.

Jan 1, 1979

Since the announcement of early experimental work on rotating magnetic field (RMF) separation at the Sixth Mill OperatorsÆ Conference in 1997, the concept of RMF separation has been developed and tested further, and a range of separator designs is now being developed for the mineral processing industry. Shortened, but full diameter, prototypes of these designs are now available for test separations. The main advantage of RMF low and medium intensity attraction separation is the significant reduction in particle entrapment. This reduction is so significant that RMF separators are capable of operating very close to their theoretical limit for separator precision. This makes small laboratory RMF attraction separators ideal for low to medium intensity magnetic sample analysis, and larger separators ideal for applications requiring sharp magnetic susceptibility splits. Feedrates and separation rates are comparable to those of conventional attraction separators. Although RMF attraction separators are now well advanced in development, RMF rotation separation is still in the early experimental stage. The exception to this is the dry particle rotation eddy current separator that offers eddy current separation of small non-ferrous metallic particles from about 2 mm down to about 100 microns. Wet small particle eddy current separation is also possible, but has not yet been developed to a practical stage.

Jan 1, 2000

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

By Yan D. S

The removal of antimony from a refractory gold-bearing stibnite ore by roasting and selective chlorinating roasting was investigated. The influence of roasting temperature, roasting time, roasting atmosphere and type and amount of chlorinating agents on antimony removal were studied. The laboratory studies carried out included roasting tests of 4 g samples in a laboratory rotary kiln, followed by 400 g samples roasted in a fluidised bed. The test results revealed that antimony was efficiently removed by roasting at temperatures over 800¦C in a nitrogen atmosphere. The most efficient volatilisation of antimony was achieved with the addition of ferric chloride at temperatures between 350-600¦C.

Jan 1, 1995

By Gregory L. M, Phillips G. N

Although it has long been recognised that there is a diversity of minerals associated with Victorian gold deposits, the degree to which this mineralogy is systematic or haphazard has remained uncertain. Recent work by the authors and students under their supervision permits a sharp delineation of the boundaries between different mineralogical domains, and these are interpreted in terms of recent rapid advances in Victorian tectonics, and the regional framework of Victorian gold geology described in Phillips and Hughes (1996).

Jan 1, 1997

Longwall mining in Australia is approaching maturity. Longwall production from 'state of the art' Australian longwall mines now rivals similar US based longwall operations. Regrettably however, Australian gate road development rates in general fall short of the required development to longwall production ratios that are required to sustain annual longwall production capabilities. By contrast, most US based longwall mines achieve the required development to longwall production ratios to sustain their longwalls. This is despite many having to drive three heading longwall panel gate headings to meet regulatory requirements.

Jan 1, 1998