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By Longworth C. R

Competing requirements for land usage sometimes make the correct all- ocation difficult. The decision can be complicated by many factors such as local resident pressure, previous government decisions, economic pres- sures and the duration or permanency of the competing land usages. This problem often confronts the extractive industries with consequent delays in granting leases and some- times considerable local dissension. A proposal to extend the high grade silica sand quarry of the Wamberal Sand Company Pty. Limited is a microcosm of these competing requirements. The sand quarry is located on the New South Wales central coast. It is an open pit operation on a near beach deposit of silica sand suitable for flint glass manufacture.

Jan 1, 1976

By A van As

This paper serves to outline the circumstances and causes of the air-blast that occurred at Northparkes Mines in November 1999. It describes the design of the mine, the geotechnical issues surrounding cave propagation and the cave monitoring systems that were in place prior to the event. A short description of the air-blast that followed a sudden collapse is given. Details of the risk assessment process that evolved during the rectification process are provided with their subsequent modification to form the core of a major hazard monitoring process. The system is in line with the recommendations given by the Coroner resulting from the inquest into the deaths of the four people who lost their lives during the air-blast.

Jan 1, 2005

By F Anthes, U Barow

Two tunnels are being bored using a æHydroshieldÆ in section 3.1 of the extension of the Underground railway line 5. At the end of the two tunnels, directly in front of the Hotel Adlon, the shields cannot be retrieved. The steel shell of the shield will be left in place within a sealed concrete block and the reusable components taken out through the completed tunnel. For the first time in Germany, an Underground tunnel is being lined solely by means of UNI rings. BerlinÆs Underground network is 165 km long and has 167 stations. Some 450 million passengers are transported annually. On account of the urban planning modifications that followed reunification, the network has to be adjusted, particularly in the city centre. The most significant project is the extension of the U5 from Alexanderplatz to the Lehrter Bahnhof. After completion, the U5 will be a continuous east-west traffic artery. It will provide a direct link with the new parliamentary and government district, open up new business districts and the cultural centre of the city.

Jan 1, 1999

By A Baensch, E Grimsley

Eloise Copper Mine is situated 56 km east-southeast of Cloncurry, Queensland, Australia. The deposit was discovered by BHP Minerals in 1986 during follow up diamond drilling of EM anomalies associated with major aeromagnetic anomalies. The deposit is overlain by 60 m of Mesozoic cover. Amalg Resources NL commenced mining during 1995 by means of decline access and long hole-stoping. The total mineral resource comprised 1.77 million tonnes at 4.10 per cent Cu as at the end of June 2003. Proved and probable reserves are 930 000 tonnes at 3.97 per cent Cu. Mineralisation is hosted within a strongly foliated Proterozoic meta-sedimentary sequence comprising arenites and schists. The metasediment sequence also contains a coarse-grained amphibolite body possibly representing an early intrusion of gabbroic composition. Economic mineralisation characteristically occurs as a number of steeply plunging lenticular bodies with strike lengths of between 100 and 200 m and maximum widths approaching 25 m. The principal orebody, the Levuka (B) Lode, displays a down plunge extension exceeding 1000 m and is open at depth. Ore mineralogy is almost exclusively chalcopyrite with the principal gangue phases consisting of pyrrhotite + quartz + carbonate. A biotite + hornblende + magnetite assemblage represents locally intense mafic alteration of the metasedimentary host sequence. Magnetite is present in variable amounts and may be locally significant in some of the smaller satellite orebodies. Within the orebodies the sulfides display a range of textures from massive through to vein like. Sulfides commonly display brecciated textures at a range of scales. Post-mineralisation faulting has severely dislocated the orebodies, resulting in a complex arrangement of fault bounded ore blocks. These faults display considerable variability in regard to strike, dip and amount and direction of throw. A recent review of the fault system by means of large-scale structure underground mapping, re-interpretation of drill core and 3D modelling has led to a significant improvement in the understanding of these structures. A significant upgrade of the geological database has accompanied the structural review. The overall improved understanding has aided the mine design processes with particular regard to decline and access development and pillar location. This has also impacted on the design of drilling programs and exploration for additional satellite ore zones.

Jan 1, 2003

The products from beneficiation present themselves at opposite ends of the spectrum, and yet numerous synergies exist in the preparation of coking coal and hematite iron ore products for their common export markets. Returning to the coal side of the business with Anglo Coal following a five-year sojourn in WA with Hamersley Iron, has provided the opportunity for comparing and contrasting some of the key synergies of the supply chains of both bulk commodities.Comparisons include consideration of things like: resource evaluation (especially quality aspects), run-of-mine handling and preparation, beneficiation, product handling and transportation, quality assurance and customer awareness, value-in-use and impacts on iron and steelmaking, and supply chain environmental aspects.Inherent within these are several other notable contrasts including: æseamsÆ and æorebodiesÆ, rocks and minerals, rejects and tailings, oxidation and weathering, suppliers and users, and marketing and purchasing, to name but a few.This paper covers some of the more interesting of these synergies and raises some potential opportunities for sharing knowledge and innovation between the two areas of activity in the future.

Jan 1, 2005

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 J Boland

Polycrystalline diamond compacts (PDC) have been widely used as cutting elements in the drilling tools for the oil, gas, civil and mining industries because of their faster penetration rates and longer bit life. US Department of Energy reports that PDC bits account for more than one-third of the total footage drilled worldwide (US Department of Energy, 2004). However, non-thermally-stable diamond composites (NTSDC) have seldom been applied to geothermal drilling, since premature failures of such PDC cutters have been observed in hard rock formations. Several factors need to be considered to prevent premature failure of cutters and improve cutting performance when using PDC-based bits and other rock cutting tools. The first set of factors consists of the strength, density, stiffness, toughness and thermal resistance of the PDC and the rock. A second set relates to the complex behaviour of the bonding between the PDC cutter and the bit matrix, or the pick and the pick holder, which is vital in maintaining stable, reliable and durable adhesion of the cutters to their hubs. Finally, based on a better understanding of the cutting processes, the formulation of a predictive model would assist in further development of cutter design.

Jan 1, 2004

By J Leppinen, B Johanson, R Kalapudas, G McMahon

The Suurikuusikko gold deposit was discovered in 1987 in western Finnish Lapland, 54 km NNE from the town centre of KittilS in the volcanic belt of Central Lapland. It is hosted by tholeiitic basalts in a graphite-bearing albitite breccia. The ore is located in subvertical shear zones characterised by strong albitisation, carbonatisation and sulfidisation. The ore minerals consist of arsenopyrite, pyrite, chalcopyrite, sphalerite, tetrahedrite, bournonite and rutile. Small amounts of pyrrhotite, gersdorffite, jamesonite, bornite, gudmundite, tetrahedrite, stibnite, kermesite, berthierite and native Sb are also present. Gold occurs as invisible and as 1 - 2 ¦m size inclusions in arsenopyrite and pyrite, on their grain boundaries and in fractures. The average amount of gold leached by cyanide is 2.93 per cent. The æinvisibleÆ gold contents were studied in pyrite and arsenopyrite by electron microprobe analysis (EPMA) and secondary ion mass spectrometry (SIMS) at CANMET/ MTL. Gold element distribution images show zoned patterns both in pyrite and arsenopyrite. SIMS analyses range from 343 to 55 ppm Au in arsenopyrite and from 217 ppm down to 0.32 ppm (detection limit 478 ppb) Au in pyrite. EPMA results range from 939 to below the detection limit 24 ppm Au in arsenopyrite and from 267 ppm to below 22 ppm Au in pyrite. Recovery of the refractory gold ore was studied using grinding, flotation, bio-oxidation and cyanidation tests. A sulfide bulk concentrate containing 40 ppm Au was obtained by flotation at 90 per cent recovery (As content 5.5 per cent, S content 22 per cent, and mass recovery 15 per cent). The grinding fineness in flotation was P80 -100 to 120 ¦m. At the original fineness the cyanidation recovery from the concentrate was lower than ten per cent, after ultra-fine grinding P80 -10 to 2 ¦m the Au recovery was less than 17 per cent. After bio- oxidation, Au recovery of 95 per cent was obtained in carbon-in-leach (CIL). The bio-oxidation time was two weeks in laboratory test, but after regrinding the oxidation rate was faster and recovery of Au higher. However, the selected method for the mining to be started in summer 2008 is open pit mining and mineral processing methods sulfide flotation and pressure oxidation in an autoclave. The ore reserves were estimated 31 December 2007 as: Probable 18.2 Mt with 5.1 g/t Au, Indicated 5.4 Mt with 3.0 g/t Au and Inferred 10.8 Mt with 3.4 g/t Au. The production capacity will be 3000 t/day.

Jan 1, 2008

In order that the processes seen may be followed in their proper 'order, the subject will be dealt with as follows, (1) Wallaroo and Moonta Mines; (2) Wallaroo and Moonta Mines Smelting Works; (3) Broken Hill Mines; (4) Concentration at Broken Hill; (5) Smelting and refining of Lead, Silver, and Gold at Port Pirie. The first acquaintance with the copper region was made at the Yelta shaft and dressing mill of the Parramatta Copper Mines Co. at Moonta. The country rock at Moonta is a hard, tough, felsitic porphyry, the copper lodes having a general strike of N. 30° Kilipping from 500 to 70°. This necessitates shaft-sinking on the lode, and underlay shafts are the rule on the field. The ore is raised in the Yelta shaft in wheeled skips, and consists of ·chalcopyrite, bornite, pseudomorphic hematite, containing, in addition, molybdenite and tourmaline. The ore from the bins at the brace is passed over a grizzly; the over-size is hand-picked into smelting ore, concentrating ore, and waste rock (00 attle ), which is sent below for filling. The under-size is elevated to a trommel having in. holes. The over-size falls on to a picking belt made up of lengths of rope strapped with iron, working over wooden pulleys.

Jan 1, 1907

By N J. Beukes, S T. Netshio, M O. de Kock

The Thabazimbi iron ore deposit comprises a series of stratabound orebodies, on average 18 - 25 m thick that are aligned along the faulted basal contact between the Penge Iron Formation and dolostones of the Malmani Subgroup, Transvaal Supergroup. Field geological relationships and petrographic observations suggest that the formation of high-grade iron ores took place after contact metamorphism related to the intrusion of the Bushveld Complex (2.06 Ga) but before the deposition of red beds of the Waterberg Group at ca 1.9 Ga. Hard, high-grade iron ores are predominantly composed of martite and microplaty hematite. Goethite is restricted to supergene-modified ores close to the Late Cretaceous û Early Cenozoic Old African land surface. At depth, the high-grade hematite ores interfinger with low-grade dolomite-hematite and calcite-hematite ores. Iron oxides (martite, microplaty hematite) present in these low-grade ores are texturally indistinguishable from those in the associated high-grade ores, ie ore formation is genetically associated with carbonate metasomatism. Microthermometric studies of fluid inclusions in sparitic carbonates and rare megaquartz reveal their hydrothermal origin. Two compositionally distinct aqueous fluids of shallow crustal origin are identified, namely a Ca-Na-rich high-salinity brine (26 wt per cent NaClequivalent, TH ~160¦C), and an aqueous Mg-K-bearing fluid of intermediate salinity (8.3 - 12.6 wt per cent NaClequivalent, TH~120 - 150¦C). The results confirm that high-grade hematite orebodies at the Thabazimbi deposit owe their origin to an event of extensive oxidative carbonate metasomatism (calcification), similar to that recognised at other important high-grade iron ore deposits in the world. Hydrothermal ore formation is both structurally and lithologically controlled. Size and quality of the orebodies was improved by Late Mesozoic-Cenozoic deep lateritic weathering as carbonate-hematite ores were enriched to friable high-grade ores, but this supergene modification is second in importance compared to the primary event of hydrothermal ore formation.

Jan 1, 2005

A review of the factors controlling stope wall behaviour such as excavation geometry, rockmass strength, induced stress, ground support, blast damage and drill drive layout is undertaken. In addition, the advantages and disadvantages of single lift stope geometries linked to vertical crater retreat are also analysed. Finally, key components of multiple lift stoping such as cut-off slots, production rings, stope undercuts and drawpoints are studied in detail.

Jan 1, 2000

By S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of quartz-reef fields that make up the greater Central Victorian Goldfield. At Bendigo gold particles are characterised by their very coarse nature, ranging from below 100 to over 10 000 ¦m in size. Some 60 per cent of the gold occurs in particles greater than 1000 ¦m in size. This characteristic ensures that the mineralisation is very challenging to both sample and evaluate. Diamond drilling provides a measure of geological structure, but is a poor measure of in situ grade, understating it by up to 75 per cent. Drilling combined with on-reef development, bulk sampling and geological interpretation has been used to define Indicated Mineral Resources. For grade control, a balance had to be sought between sample representivity, cost, turn around time and practicality. Sampling of extreme nugget effect deposits generally requires the use of bulk sampling in order to be representative. However, the cost and turn around time is significant. As a result, a 50 kg micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can discriminate between ore and waste. As the mine passes into production, grade control will increasingly become dependent upon geological data collection and interpretation.

Jan 1, 2005

By Rowe J

The case study is based on the largest ore deposit at Mt. Lyell; the Prince Lyell deposit, comprising a regular lensoid mass of dissemina- ted and vein pyrite-chalcopyrite mineralisation. Reserve estimation employs conventional techniques, based on diamond drill hole and relevant development sampling data. Probable ore reserves are estimated using the contouring (isoline) method an longitudinal projections for ore thickness and accumulation (m %Cu) at a '0.8% Cu' cutoff. Final stope and pillar res- erve estimates (proved ore) are derived from designed ring tonnages and contoured accumula- tion for individual mining units, following more intensive sampling. Systematic grade control procedures have been adopted and individual stopes and pillars reconciled against mill production. The proved ore estimates have been found to com- pare favourably with the reconciled production.

Jan 1, 1979

By P Dare-Bryan

Many mines have an interest in improving fragmentation at their sublevel caving operations in order to produce better ore recovery, lower dilution and less overbreak. The primary requirement for the extraction phase is to understand and optimise the flow of the fragmented rock in the rings including interactions with the caved material. Rock fragment formation is critically controlled by the blasting phase and can potentially be improved by optimising the dynamic energy distribution throughout the ring through the crafting of explosive charging, priming position and initiation timing. The modelling of fragmentation and damage due to explosive loading of complete rings is inherently and irrevocably a three dimensional problem that is difficult to address. We have therefore initially utilised an analytical code to predict vector peak particle velocities and energies that are restricted to the plane of a ring. Dynamic energy distributions based on common timing and priming practice have been compared with other possibilities using conventional pyrotechnic detonators as well as initiation designs based on accurate electronic detonators. The energy distribution can be quite subtly tailored to increase energy in appropriate regions or to decrease energy in the brow region for example to potentially reduce instability and the probability of misfires. We have also recently developed the capability to efficiently model particle flow using four-sided polygonal elements. Despite the 2D limitations of such a model this results in more realistic fragment interaction and stacking than can be achieved using conventional rigid circular elements. Modelling of a typical sublevel caving ring utilising these elements activated by the correct dynamics offers considerable potential for understanding the influence of the blasting energetics and timing on the complex flow and extraction process.

Jan 1, 2005

By Wilkins L. G

Ore recovered by North Broken Hill Limited as a result of mining operations at its Broken Hill leases is obtained, at the present scale of working, in the proportions of 80% from the North mine and 20% from the British mine sections, and is composed mainly of a silver bearing, sulphide lead and zinc mineral, in association with the gangue materials mentioned later in the text.The lead-zinc sulphide lode at the North mine is deposited in folds in pre-Cambrian sedimentary schists. These folds pitch north-east at approximately 40° and dip north-west at approximately 60°. In plan the deposit appears as two lenses designated on the mine as the "Southern" and "Northern" ore-bodies.The Southern ore-body yields the main tonnage of crude ore. The sulphide mass here overlies a heavy layer of rhodonite which persists with the pitch of the lode. In the central section of this ore-body the sulphide zone is coarse grained and of high grade with a wide range of minerals in the gangue dilution. Quartz, garnet, ftuorite, rhodonite, and felspar are common, whilst chalcopyrites, pyrites, pyrrhotite and green felspar are often present. The Northern ore-body is dolomitic to siliceous in nature. Crude ore obtained from the British section is predominantly...

Jan 1, 1940

By Orr D. B

This is a case history of prospec- ting carried out by Comstaff Pty. Ltd. over the Pinnacles Area, part 4 of Exploration Licence 5/63, 9 km north of Rosebery in Western Tasmania. Evidence is presented to show that A 0 soil samp ling is a viable prospecting method for outlining polymetallic sulphide occur- rences in areas where leached organic/ glacial soils are common. Diamond drilling of low threshold anomalies has intersected base metal mineralisation.

Jan 1, 1977

By R F. Sandenbergh

Due to environmental considerations, mineral processing plants are increasingly recycling water to decrease the impacts of wastewater on environment and the depletion of fresh water resources. Industrial experience has shown that increasing recycling water in flotation typically negatively impacts the recovery and selectivity, especially in the selective flotation of minerals from complex sulfide ores. The major reason for the reduced selectivity is typically the inadvertent activation of sphalerite or pyrite by the heavy metal ions (HMI) in solution. These HMI are often produced during milling and flotation and absorbed by other minerals. In the normal flotation pH value range (8 - 10), these HMI are often in the form of precipitates or complex ions that may re-appear in solution or become active should conditions favour this. In this paper, microflotation, batch flotation and XPS surface measurement were used to investigate the use of HMI absorbents additions to the pulp to improve flotation selectivity of a complex sulfide ore. It has been demonstrated that HMI removal does improve flotation selectivity by facilitating more effective depression of the sphalerite. Microflotation and XPS surface measurements have shown that HMI absorbents compete with sphalerite to absorb HMI, and thus reduce the surface concentration of HMI on those sulfides. The practical use of HMI absorbents in complex sulfide ore flotation is also discussed.

Jan 1, 2005

By J Ferreira

To speed up multivariate geostatistical simulation it is common to transform the set of attributes into spatially uncorrelated factors that can be simulated independently. One decorrelation method is the method of minimum/maximum autocorrelation factors (MAF), where a two structure linear model of coregionalisation is assumed. The transformation decorrelates the theoretical model exactly, but the actual data are only approximately decorrelated. The MAF transformation can therefore be seen as a special case of a non-orthogonal approximate diagonaliser of a set of symmetric matrices. A more general approach for approximate joint diagonalisation (AJD) has been developed in the context of blind source separation. For these AJD algorithms no assumptions are made beyond symmetry of the individual matrices and so they can be applied to a family of experimental semivariogram matrices. In their application there are no restrictions on the number of structures in the linear model of coregionalisation (LMC) thus removing one of the conditions placed on the subsequent modelling of the spatial structure of the factors. In this paper the general background for the U-WEDGE AJD method is presented. It is shown that the U-WEDGE method achieves better spatial decorrelation than the MAF method. The factors derived from U-WEDGE are simulated using conditional turning bands simulation and then backtransformed to attribute space.

Sep 26, 2011

By G D. Carman

White Rock is a reduced tungsten-tin skarn deposit near Rye Park, New South Wales. This abstract summarises the depositÆs mining and exploration history, and current exploration by Paradigm Metals Ltd targeting an economic resource at the deposit. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

In many mining operations, the truck and loader equipment represents the bulk of the invested capital and the majority of the mine operating cost. The profitability of these mines is therefore critically linked to the efficiency of the truck and loader operations. The various factors which affect the productivity of trucks and loaders are analysed by computer simulation, and the results presented in a form allowing assessment of the importance of each factor on overall productivity.

Jan 1, 1983