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A method for determining the relative degree of oxidation of concentrate samples was established, and various surface-active materials and protective systems were examined as oxidation inhibitors. Sodium oleate was-the most effective of the materials tested, and a plant trial

Jan 1, 1963

By S R. Grano

The selection of the proper frother, specifically for a given ore, is essential in flotation. Traditionally, strong and stable froths are required in the scavengers, where metal recovery needs to be maximised, while selectivity must be achieved in the roughers and cleaners, where grade of concentrates is the main issue. The physical properties of a froth are determined both by frother type, by process water composition and by the amount and nature of the suspended particles. The evaluation of different frothers, in terms of metallurgical performance, is complicated at plant scale, since it may lead to periods of malfunctioning of the process and unacceptable decreases in recovery. On the other hand, evaluation based on frother chemistry only, is often unsatisfactory, because the frothing response is strongly ore dependent. A procedure, and proper tools, was developed at the Wark in order to perform the screening of candidate frothers at batch scale on real pulp samples. The main parameters related to froth stability (half-life time, froth height) are measured after introducing the pulp samples into a foaming column, where different conditions in terms of frother addition, agitation and aeration can be maintained. The approach has been applied to the selection of frothers for the flotation of an Australian sulfide ore. Procedure and results are discussed.

Jan 1, 2006

By Cook B, Cunningham J

At Mount Isa Mines, a system has been developed for general monitoring of underground mobile equipment. It can provide unit condition monitoring data such as oil pressures and motor temperatures as well as production type information such as unit location and load. The system does not rely on an expensive data communications infrastructure, using instead inexpensive radio base stations which automatically transfer data from mobile units to a surface database server on the company-wide computer network. This paper includes a general overview of the system and a discussion of the practical benefits it is expected to generate.

Jan 1, 1995

The Cleveland Mine has an annual ore production of 400,000 tonnes at a grade of 0.79 per cent tin and 0.30 per cent copper. It is achieved by an open stoping method, mechanised overhead sub-level benching. The operation is trackless with a ramp access from all working places to the surf- ace. Broken material is loaded from the stope and development headings into diesel trucks and hauled to the surface crushing plant.

Jan 1, 1977

The Regional Development Council has initiated a project that aims to find better ways for further investment by extractive industry companies in sustainable regional and community futures. It will be undertaken through collaborative actions that bring together the resources of private and public sector stakeholders in regional Western Australia.   The broad objectives of the project are to: describe and analyse the current situation with respect to the impediments to regional communities being more self sustaining, assess the effectiveness of the current and possible future levels of investment by extractive industry companies in the sustainable development of communities in regional Western Australia, identify and demonstrate collaborative ways in which extractive industry companies in Australia and other countries can play an enhanced role in sustainable regional and community sustainability through strategic engagement and investment; and confirm the effectiveness of the collaborative measures in delivering sustainable outcomes for regional communities by way of attracting and retaining populations and enterprises in Australia and similar environments.

Jun 1, 2010

By Yucheng H, Baogui Y, Wenyong L

High-water rapid-solidifying material, called 'high-water material', is a new material developed by the authors over many years. The material can solidify nine times its volume of water into solid. The material is a fine kind of binder with special properties. The solidifying body of high-water material with water has quite a high early strength. The compressive strength of the material within three days can reach the same strength as conventional Portland in 28 days. One ton of the material can replace three tons of conventional Portland cement as binder. Some important achievements have been made in application of high-water material. In metal mines, based on the material, a new full-tailing cemented backfill technology has been developed. The characteristic of the new technology is that high-water material is used as binder and full tailing or alluvial sand is used as backfill aggregate. Because of the application of the new technology, major technical problems in backfill technology such as classifying of tailing, dewatering, transportation of pulp, low strength of hackfill body. environmental contamination and so on, have been solved.

Jan 1, 1998

Ok Tedi Mining Limited has recently completed the first phase of a trial to compare the performance of D26B Krebs cyclones in different configurations to the new Warman 650 mm CAVEX cyclones. From 1992, rougher flotation feed size has increased from the target d80 grind size of 150 ¦m with increasing SAG mill throughput. At high SAG mill throughput, operators have difficulty maintaining the target cyclone feed pressure and must increase the cyclone feed density, thus resulting in a coarsening of the cyclone split. Warman International have developed the CAVEX high capacity cyclone. The new CAVEX cyclones, when compared to the Krebs units appear to:produce a measurable increase in volumetric flow for the same pressure drop; maintain or decrease the proportion of coarse particles reporting to overflow; and lower the overflow density. In all plant trials to-date, the CAVEX cyclones appear to be superior to the standard Ok Tedi Krebs cyclones. Further testwork is planned to evaluate modified Krebs cyclones (with recent design improvements) against the CAVEX cyclones.

Jan 1, 2000

The traditional concept of optimum drill and blast is that it is achieved when ore is produced at the lowest unit cost and, because of the complexities of most mining operations, represents a band which extends either side of an overall cost m

Jan 1, 1998

Industrial relations on Australian and New Zealand resource projects can be volatile. Therefore investors have become increasingly aware over the years that sound industrial relations during construction is vital to the overall success of their project. There has been a wide range of actual industrial relations performance, project by project, and the degree. of success often directly correlates with the degree and thoroughness of pre-project planning. However, although many projects have been crippled by delays and cost overruns because of labour disputes, good results are achievable. Total commitment to the project by all parties involved is essential and it is up to the employers to seek out this commitment and not just trust mother luck. Industrial relations must be taken very seriously as the price of failure can render a resource project unviable.

Jan 1, 1983

By G Diprose

Diamond exploration in Queensland is influenced by the South African approach modified by the discovery of diamonds in Lamproite in Western Australia. The current approach is to explore for Kimberlite and Lamproite bodies using indicator minerals dispersed by fluvial and colluvial processes. In the north-west, diamonds are derived from kimberlitic and lamproitic sources, whereas those in the coastal and subcoastal areas of eastern Queensland are associated with xenoliths included in rocks formed during Cainozoic volcanism. In these areas, sapphire is commonly associated with diamonds. In New South Wales diamonds in economic quantities occur in alkali basaltic intrusions and a subduction model has been proposed for these occurrences (Barrows et al, 1996). Exploration for diamonds in Australia increased following the discovery and exploitation of the Argyle mine. State geological surveys have produced digital information on the local occurrences of diamonds. As part of the Smart Mining Initiative (2006 - 2010), the Geological Survey of Queensland compiled a database and report on microdiamonds and diamond indicator minerals from open file company exploration data from 1968 to 2008 from the Department of Mines and EnergyÆs QDEX system. Most exploration in Queensland was conducted with exploration for other commodities. There is no commercial exploitation of diamonds in Queensland and, to date, only rare occurrences of microdiamonds. There is a regional difference in diamond occurrences with the kimberlitic and lamproitic models favoured for the north-western regions of the State and the subduction (S-type model) favoured for the eastern coastal zone linked to Cainozoic alkalic basaltic volcanism. Further diamond exploration is warranted in Cainozoic basalt provinces along the eastern coastal and near coastal regions and in the north-west of the state in conjunction with airborne geophysics flown as part of current Departmental Smart initiatives. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By M P. Sandy

Some Western Australian underground mines are challenged by very high stress gradients. This environment frequently results in poor induced ground conditions and damaging seismic activity. In some cases, rockbursting or squeezing ground has been observed as shallow as 250 m below surface. Very few mines operating at depths greater than 500 m experience no stress-related issues. As a general result of this difficult environment, there are a growing number of mines that are now challenged or have been closed by induced geotechnical problems. Often, the up-front savings or perceived advantage of an inappropriate mine plan may be entirely lost to the real cost of managing the hazards, or a write-down of reserves resulting from access difficulties will diminish the economic position of the mine. From an engineering perspective, it is best if stress-related hazards can be proactively minimised, because reactive measures offer less improvement in risk exposure. In this paper, some examples of sequencing techniques for managing difficult environments are contrasted with examples from mines where developing hazards have adversely affected production or the economic viability of the project.

Jan 1, 2003

By B K. Hebblewhite, G Sharrock

The strength and deformation properties of a rock mass are important parameters influencing the design of civil and mining excavations or structures. The mechanical behaviour of jointed rock masses are controlled by the characteristics of discontinuities and the strength of intact rock bridges between discontinuities. To date, analytical, empirical and experimental methods have not captured the key mechanisms controlling the mechanical properties of actual rock masses with non-persistent joints. The emergence of the synthetic rock mass (SRM) in 2007 provides a promising approach for this purpose. In this paper a rock mass with non-persistent joints is analysed with the SRM model based on PFC3D. The influence of joint geometrical parameters on the uniaxial compressive strength (UCS), rock mass deformation modulus (Em) and failure mode is studied. Joint parameters include joint orientation, persistency, spacing and step angle. Prismatic numerical samples with dimensions 300 mm × 150 mm × 50 mm were generated and a sensitivity analysis of each joint parameter on UCS and Em was undertaken. The results show that of the parameters tested, joint orientation has the greatest influence on UCS. Minimum UCS occurs when the angle between the major principal stress and joint surface is approximately 60°. The joint step angle was found to have a significant effect on failure mode and a joint step angle of 90° is the most favourable joint orientation for step-path failure. The importance of joint step angle is highlighted in the discovery of a failure mode bifurcation point at joint step angles of 60° and 90° for joint orientations of 75° and 90°, respectively. For these parameters the failure mode transitions from block rotation to a new failure mode where the coalescence of cracks results in the formation of new small regularised blocks.

Sep 26, 2011

Declines for both access and rock haulage are replacing shafts for mining relatively shallow deposits of down to 1000 m below surface. Where the orebody does not outcrop and where surface access may be restricted, it is often necessary to drive long dead end headings before a connection can be made back to surface and a ventilation circuit created. In hot tropical areas and where large diesel powered equipment is used for mining, heat may also be a problem at these relatively shallow depths. The normal design criteria based on statutory limits and good practice used to evaluate ventilation and cooling requirements in terms of air velocity, dust, gases, diesel exhaust dilution, re-entry after blasting and heat stress are described in this paper. These are then used to design and cost alternative auxiliary ventilation systems that include leakage based on general fan performance curves and typical duct systems. The implications of the current European Community recommendations regarding nitrous fumes are also briefly considered. The actual problem relates to a 2100 m long decline that may have to be extended to 3000 m long without a connection to surface or through ventilation and is located in a hot tropical area where the surface wet bulb temperatures may exceed 25¦C for more than a third of the summer period. Once the preliminary ventilation design is completed, the auxiliary ventilation system can be modelled and simulations undertaken that incorporate heat and moisture transfer routines with the objective of determining the cooling load and amount of refrigeration required. Cognisance is taken of cyclic diesel operations and the thermal flywheel effect of the surrounding rock on the wet and dry bulb temperatures resulting from these operations.A suitable modular cooling system located at the portal is described and optimised with capital and operating costs of both the ventilation and cooling systems provided.

Jan 1, 2005

By Bensley C. N

In June 1995, BHP announced that it would build a Hot Briquetted Iron (HBI) plant and associated beneficiation, materials handling and infrastructure facilities at Port Hedland, Western Australia. This plant, the first direct reduction plant in Australia, will convert beneficiated iron ore fines into metallic iron for briquetting into HBI. The reduction plant will be based on the FINMET fluid bed technology jointly developed by Fior de Venezuela and Voest-Alpine Industrienlagenbau. Electric Arc Furnace steelmakers in the Asia Pacific region will be the principal customers for the product. This paper presents an overview of the facilities to be constructed by the project as well as discussing some particular technology and design engineering issues associated with the project.

Jan 1, 1996

By Henderson J, Ward RG

Dissolved oxygen has been measured directly using a rugged, reliable, accurate electrochemical probe system developed for steelworks application by B.H.P. Central Research Laboratories. Furnace measurements show that the steel is generally supersaturated with oxygen and that oxygen contents vary considerably from heat. to heat. Ladle measurements also show considerable heat-to-heat variations. Analysis in terms of ladle deoxidation chemistry differentiates between carbon monoxide controlled and manganese silicate controlled oxygen levels. Deviations from these levels are sometimes due to aluminium present in other added ladle alloys but in some cases the plant applicability of laboratory derived equilibria is questionable.

Jan 1, 1972

By Martinick WG

In July 1986, Cable Sands (W.A.) Pty Ltd commenced mining for mineral sands at Minninup, approximately 16 km south of Bunbury, Western Australia.The area being mined is from the heel of the foredune to the rear of the hind-dune. The vegetation is mostly native vegetation with some old degraded pasture.The mining operation will be by suction cutter dredge, with continuous dredging, mineral separation and re-depositing of the sand.

Jan 1, 1986

By Iley J. D

The production of zinc from low grade concentrates, particularly those high in iron, has a poor economic return due to a combination of higher concentrate transport costs, increased processing costs and an increased cost for disposal of iron residues. The production of iron-bearing residues from the electrolytic zinc process is also seen as undesirable for both cost and environmental reasons. This paper details the pilot plant testwork conducted at the Pasminco Research Centre in conjunction with Minproc for the production of zinc oxide fume from a high-iron zinc sulphide concentrate from Colquiri in Bolivia. The concentrate is derived from a tailings retreatment operation and has a high iron content (40 - 45 per cent Zn, 14 - 17 per cent Fe) due to the presence of marmatite. Pilot plant trials were conducted using the slag bath reactor at Pasminco Research Centre at rates up to 500 kg/h of pelletised zinc concentrate, using a natural gas/oxygen-enriched air lance. The fume produced averaged 76 per cent Zn at recoveries up to 96 per cent and was recovered in a baghouse after gas cooling. The iron was oxidised into a fayalitic slag that passed the TCLP test (toxicity characteristic leaching procedure) and the sulphur was oxidised to produce a high SO2 gas which would be suitable for sulphuric acid production. The process produces a zinc oxide fume that can replace calcine as a feed for electrolytic zinc plants. The iron reports to a stable slag for disposal, thus eliminating the need for its disposal as jarosite from the leach plant. Only a simple leaching operation on the fume is required as there is no zinc ferrite present.

Jan 1, 1993

By Nilsson C

Man has always been and will always be part of his environment, in ,a good, bad or indifferent manner. Until quite recently, this environment has been the atmospheric boundary layer above the land masses, and to a limited extent the air-sea interface of the oceans. Since the days when he lived in caves, he has built up a wealth of observations on these two environments,-with ever-increasing scientific precision which unfortunately until quite recently was completely insufficient for modern capabilities of data analysis. Consequently, in a sense, he has left in his wake thousands of years of missed, opportunities for making exact observations and increasing his understanding. The data of the past are lost and he has to be satisfied with what he can assemble from now on when his environ- ment, largely as a result of his actions, is exhibiting more and more rapid variations in time; in other words, time series of observations of phenomena are required, the length of which is critical for most purposes of analysis.

Jan 1, 1970

The Highlands Region of Papua New Guinea has 3 major national highways. The locations of these national highways are shown in Figure 1. The Highlands Highway begins at Lae City on the coast and passes through the Highlands towns of Goroka, Kundiawa and Mt Hagen. It terminates at Togoba approximately 10km out of Mt Hagen town. The Enga Highway begins at Togoba and passes through the towns of Wapenamanda, Wabag and Laiagam. It terminates at the giant Porgera Gold Mine. The Southern Highlands Highway also begins at Togoba and passes through the major towns of Mendi, and Tari. It terminates at Koroba station, near the Hides Gas Field. Two separate Feeder roads intersecting the main highway service both the Kutubu Oil Project and the Hides Gas Field. These national Highways play a very important role in the development of Papua New Guinea. Goods and services are delivered to the bulk of the population of the Highlands Region using these highways. Heavy machinery and equipment for the mining and petroleum projects of Porgera, Hides and Kutubu are transported using these roads.

Jan 1, 1997

By Kallioinen J

This paper discusses different possibilities to enhance coarse particle flotation using forth manipulation and improved flotation cell design. Experiments were carried out in laboratory, pilot and industrial scale ranging from 0.0015 to 100 m3/axle. During the work it could be shown that the conventional idea of one single flotation cell type for both fine, immediate and coarse flotation of coarse and fine particles need different impeller tip speeds and a different froth control objective for effective operation. For optimal operation for coarse feeds the tip speed must be reduced and the froth vertical velocity must be increased to compensate the respective drainage velocity and also the water film thickness must be taken care of. Turbulent eddies below the froth interface should be suppressed. The paper discusses the effects of different froth manipulation variables like froth vertical velocity and froth residence time to the recovery and selectivity. A function has been developed, between the residence time of the froth and the flotation cell's ability to produce an improved concentrate grade as a function of different operating and froth manipulation variables.

Jan 1, 1993