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By C Garlick, O Gregory, H Rogers, B I. Winters, Z C. Ye

BHP New Zealand Steel produces iron from titaniferous ironsand by a direct reduction process comprising multihearth furnaces/rotary kilns/electric iron melters. The electric iron melter is a six-in-line rectangular submerged-arc furnace which takes the partially reduced ironsand (80 per cent metallisation) from the rotary kiln and completes the reduction process to produce iron of nominally three per cent carbon. As the melter operates at around 1500¦C and under very hostile conditions, it is near-impossible to obtain any basic operating parameters such as the velocity and temperature distribution in the slag and in the molten iron. As a first attempt to understand the operating conditions inside the melter, a scaled room-temperature model using wax and water to represent the slag and iron, was constructed. This paper will report on some of the preliminary model results on the temperature distribution.

Jan 1, 1995

By S Vianna, K Caldwell, R Silva, T Olson, D Bell

Studies to enhance the FLSmidth forced air machine through changes in the design, showed important improvements through changes in the number of Rotor blades, stator designs, rotor air distribution and other designs features. The main outcomes from this study highlighted that increasing the number of rotor blades increased the selectivity while decreasing power requirements while stators with slots have better results in terms of recovery, flotation efficiency and selectivity than without slots.Also the rotor air distribution makes a difference in the design when comparing different distribution criteria whilst keeping all features of shape and number of blades etc constant. At the most efficient rotor air distribution design, copper recovery reached one of the highest values while keeping good selectivity. The possible explanation for that is the increase in the pump capacity indicated by the increase in the specific power.It was seen as significant that reduction in specific power for some designs tested compared with the then current standard design had an average of 30% less power consumption.As a result, FLSmidth was able to identify new designs that decreased power and improved recovery, as well as, identifying some designs that specifically improved fine and/or coarse particle recovery.CITATION:Silva, R, Caldwell, K, Bell, D, Olson, T and Vianna, S, 2013. FLSmidth flotation developments - Dorr Oliver machines, in Proceedings MetPlant 2013 , pp 413-430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

The recent boom in the mining industry has lead to some unique challenges in successfully operating processing plants. With high turn-over rates of both operators and technical staff, and many experienced personnel leaving regional sites for city based jobs there is often an onsite knowledge vacuum and this in turn puts pressure on both site training departments and senior metallurgists to provide the relevant skills to the continuous stream of new staff. Frequently both operators and new metallurgists are instructed on a æhow-toÆ basis rather than giving them the understanding as to why tasks are performed and decisions are made. This paper has been written with the plant operator and metallurgist in mind and aims to provide suitable material to be incorporated into a site training manual. Topics have been broadly divided into the following categories: factors that operational staff can control; including pulp density, air addition rate, froth depth, particle size and reagent type and use; factors that operational staff cannot control; providing general information on bubble size, froth stability, pulp chemistry and the mechanical effects of the rotor/stator system; and process improvements. Each topic is discussed with a view to clarifying the key process variables that need to be understood and optimised in an industrial operating plant.

Jan 1, 2009

If the industry keeps doing what it has always done, it will continue to get what it has always got - rising operating costs. Why is this so? Generally grades being chased are becoming lower, stripping ratios becoming higher, ability to attract personnel to the industry becoming harder and/or more expensive, higher safety standards are being demanded and environmental governance is being enforced.   How then should the surface mining industry plan for the future whilst delivering on improved safety and the environment? In-pit crushing and conveying (IPCC) points the way, as a partial or complete substitute for trucks.   IPCC systems promise significant advantages over traditional truck and shovel operations, including improved safety, reduced operating costs, reduced dust and noise emissions, far greater efficiency in energy use (electric versus diesel motors predominantly and the ability to regenerate electricity back into the local grid for downhill situations), reduced carbon emissions (dependent on power generation source) and reduced water consumption. Despite these advantages, there is a general industry reluctance to migrate from truck and shovel operations. This reluctance stems from a familiarity with truck and shovel operations and a perceived concern that IPCC lacks flexibility which will negatively impact on the mining operation.   In studies conducted since 2007 (with the new modular builds) comparing IPCC with truck-optimised pit designs, IPCC has delivered up to USD$0.82 per tonne moved less than an equivalent truck operation. In addition, IPCC is easily automated from a central control room (local or remote) - something that trucks have yet to commercially achieve.   IPCC is a proven process that, with a fresh mindset, can make a significant improvement to mining operations - its safety, the impact on the environment and its costs. It maybe of interest to note that there is over 200 IPCC installations worldwide today.   This paper and presentation will assist in furthering the understanding of IPCC and its applicability.

Jun 1, 2010

A pilot steel ladle injection facility designed to assist in the production of high quality steels suitable for use in pipelines has been built and commissioned at the Basic Oxygen Steelmaking (BOS) plant at Port Kembla Works.The plant design and the injection procedure are described.The performance of the unit and some metallurgical results are discussed in terms of the addition to the steel ladle of various quantities of calcium silicide and a lime based material. The effects of these additions on sulphur content and inclusion morphology and hence on steel ductility are also presented. The influence of ladle lining on desulphurisation is illustrated.On the basis of the experience gathered in the pilot plant a permanent and more sophisticated injection facility has been designed.

Jan 1, 1983

By Bratt G. C

When zinc is electrowon from concentrates or residues of high manganese content, the zinc sulphate electrolyte may contain high levels of manganese. The manganese level is usually controlled by removal of manganese at the anode as the dioxide during the zinc electrodeposition stage.By increasing the temperature of an electrolyte containing 8 gll manganese from 35°C to 90°C, decreasing the acidity from 100 gll to 30 gll, reducing the current density from 432.A.m-2 t6 286 A.m-2 and using new lead anodes containing over 0·75 per cent silver, the current efficiency for manganese dioxide removal was .increased from less than 1 per cent to over 20 per cent.At the same time the current efficiency for zinc deposition was maintained above 90 per cent by additions of high molecular weight cationic polyacrylamides to the cell. By utilization of these conditions in a small number of cells, the manganese level in the circuit could be economically concrolled to any desired level.With these conditions the formation of the dioxide changes from an indirect route, via Mn04-, to a direct oxidation of Mn2+ to Mn02.The incorporation of impurities such as Pb, K, NH4, Cu, Ni, or Fe makes the deposit unsatisfactory for direct use in Zn - Mn02 dry cells. The deposit structure changes from cryptomelane at low temperature to y3-Mn02 at high temperature.

Jan 1, 1975

By Uusna S, Canning R. G, Goodheart B. A

The development of a process for removal of iron oxides from ilmenite is outlined whereby the Ti02 content of Western Australian ilmenites can be upgraded from 55 to approximately 90 per cent. In the first stage, the iron oxides are reduced with solid carbon (coal) to metallic iron. Experimental reductions were carried out in crucibles, a fluidized bed, and a small pilot plant rotary kiln. The reduced ilmenite was then agitated in aerated water, in the presenceof catalysts, so that the iron "rusted" away from the ilmenite grains and the precipitated iron oxide was easily separable by decantation.The influence of variables on the rates of reduction and oxidation are discussed. The oxidation rate was examined for both the physical oxygen transfer characteristics and electrochemically by reference to Pourbaix diagrams, in which redox potential is plotted against solution pH.The upgraded ilmenite is expected to be an attractive material for pigment manufacture, and the iron oxide has prospects of being a marketable by-product. The process may possibly be applied to other ores.INTRODUCTIONThere are extensive deposits of ilmenitic beach sands, Le. iron titanium oxides of the general formula FeTi03, 'occurring in the lower south-west portion of Western Australia, and although there has been considerable commercial development, local producers face keen competition on a freight-cost basis. Thus the removal of the unwanted iron oxide constituent would have the double advantage of reducing the freight differential and presenting a more attractivematerial to pigment manufacturers.

Jan 1, 1965

By N E. Whitehead

An application to mine an ilmenite-rich sand deposit in Westland led to public concern about potential radioactive hazards should the ore be further processed to recover zircon or monazite. A review recommended that any material involved in the heavy mineral sand industry containing more than 0.05% thorium, uranium or their mixture should be considered a radioactive substance and, for mining purposes, a notifiable product. Safeguards for those occupationally exposed would operate via the Radiation Protection Regulations. The major safety requirement would be the minimisation of dust in certain operations.

Jan 1, 1993

Variations in product distribution in the carbon-sulphur dioxide system due to variations in reaction temperature, sulphur dioxide concentration in the feed gas, and gassolid contact time were studied in detail for a brown coal char. The results were compared with those for two wood chars, a coke prepared from Liddell coal and two cokes prepared from Ac1and coal. Conditions were chosen such that gas-solid diffusion rates did not hinder chemical attack of the carbon.With brown coal char under suitable conditions, the selectivity of sulphur in the sulphur dioxide fed, to either elemental sulphur or carbon disulphide, was in excess of 90 per cent. The wood chars gave very similar product distributions Ito brown coal char. However, the cokes from Ac1and and Liddell coals were respectively approximately three and seven times less reactive than the brown coal char.The approximate carbon holdup required to just achieve total conversion of sulphur dioxide, and thereby achieve high selectivity to elemental sulphur, is given as a function of reaction temperature.

Jan 1, 1974

An account is given of experimental apparatus for generating a short duration high velocity water jet and the effect of its impingement on various rock samples under air or water cover. The penetration was found to be highly dependent upon the rock structure; in general material with closely interlocking grains was resistant.The damage sustained by a stationary sample held close to the jet did not vary greatly whether the sample was in air or confined under a water layer; but when the sample was translated under the jet there was a marked increase in the damage sustained.Some consideration was given to the possible practical application of a water jet for deep hole drilling and an estimate made of the power requirements and transmission losses for such a system.

Jan 1, 1969

The Hyde Macraes Shear Zone (HMSZ) is an extensive low angle semibrittle mineralised structure in the Otago Schist Belt, New Zealand. The shear zone is located on the lower limb of a late metamorphic recumbent fold. Structural observations suggests that the shear zone initiated as a high strain mylonite zone and transgressed the ductile/brittle boundary (D4) later in its development. A surge zone at Round Hill is bounded to the south by a NE-SW striking lateral ramp which displaces the hanging wall shear (HWS) by 50 m. Oblique strike slip displacement during surge zone propagation created space for deposition of the sheeted vein complex or stockwork. Quartz recrystallisation in stockwork veins suggests that the veins were deformed in a ductile manner and implies that surge zone propagation may have occurred during late D3 deformation. A macroantiform was produced during D3/D4 shortening below the HWS. Over tightening of the antiform hinge created SW and NE-dipping ramp thrusts. Continued strike slip displacement along the lateral ramp rotated the antiform and associated ramps into a south plunging drag fold. Post-mineralisation (D5) structures include NE-dipping nonna! faults below the HWS and SW-dipping low angle imbricate thrusts above the HWS. The development of these structures was kinematically compatible with normal movement on the HMSZ and is related to mid Cretaceous break up of Gondwanaland in the SW Pacific.

Jan 1, 1992

By C Li, D O’Dea, R Moreno-Atanasio, T Honeyands

The behaviour of iron ore granules in the feeding process of sintering is significantly influenced by the material properties of the granulated mix. Therefore, the measurement of key material properties of the iron ore granulated mix is indispensable prior to the simulation of the sintering process based on the discrete element method (DEM). In this paper, three key property parameters of the iron ore granulated mix, apparent density, elastic modulus and rolling friction coefficient, were measured in laboratory-scale experiments. For different sintering processes, the moisture content of the granulated mix normally varies according to the specific requirements for granule size distribution and operating conditions. Therefore, understanding the effect of moisture content on the property parameters of iron ore granules is very helpful in accurately determining the property parameters for DEM simulation work. In this paper, six groups of iron ore granule samples with six levels of moisture contents were prepared through granulation and the trends in apparent density, elastic modulus and rolling friction coefficient with the increase of moisture content were plotted and analysed based on the measurement results. The results show that as moisture increases from 6.9 per cent to 9.1 per cent, the apparent density decreases from about 3000 to 2800 kg/m3. With moisture increasing within the same range, the elastic modulus first decreases from over 200 MPa to below 100 MPa and then reaches a relative constant value of about 40 MPa at higher moisture contents. Rolling friction coefficients are measured using two methods with both indicating a similar trend, with the rolling friction coefficient first decreasing and then rising as moisture increases from 6.9 per cent to 9.1 per cent. The relationship between µr and µ’r is assumed to be similar to that between static and dynamic friction coefficients.CITATION:Li, C, Moreno-Atanasio, R, O’Dea, D and Honeyands, T, 2017. Variation in property parameters of iron ore granulated mix with moisture content, in Proceedings Iron Ore 2017, pp 79–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By B S. Utting, W J. Cowie

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850s has been an estimated 480 t (15 Moz) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 t of gold for 1989. Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By L A. Maslov

We have considered the following characteristics of the crust and upper mantle of the Pacific Belt: seismic wave velocity anomalies, mechanical stress and shear deformation rate fields, heat flow and the pattern of metallogenic provinces of the Belt. It has been noted that there exist certain .regularities in distribution of the above mentioned geophysical characteristics and metallogenic zones within the Belt, displayed by prevalence of the lithophile elements in the Asia-Australian part of the Belt, and of the chalcophile ones within the American part.

Jan 1, 1995

Laboratory scale equipment was developed to recover zinc as oxide fume from granulated lead blast furnace slag. The cyclone furnace process is characterised by high treatment rates combined with continuous and independent operation.Results were sufficiently encouraging to warrant pilot plant scale trials being undertaken.INTRODUCTIONSince granulation of lead blast furnace slag started at Port Pirie in 1921 the stockpile of this material has increased to nearly 5 million tons which averages 17·5 per cent zinc by weight. Although a number of processes for recovering the zinc have been examined, economic considerations indicate that a slag fuming process is likely to be most suitable.In the conventional slag fuming process zinc is extracted by injecting pulverized coal and air into a molten slag bath. By maintaining a suitable air to coal ratio the oxidised zinc contained in the slag is reduced to metal. Volatilization of the zinc is followed by reoxidation in the gaseous phase with the addition of further air above the bath. The zinc oxide fume so produced is collected by normal gas cleaning methods.By examination of the thermodynamics of this process Bell, Turner, and Peters (1955) determined the zinc oxide activity of the slag over the duration of the fuming cycle.A combination of high temperature and high carbon monoxide/carbon dioxide ratio was found necessary for rapid zinc elimination.Since melting of the slag is an essential step in the slag fuming process, only two treatment methods appeared possible at Port Pirie until recently...

Jan 1, 1964

If lead buttons are cupelled under closely controlled conditions in a suitable design of furnace, silver losses during cupellation are given by a simple equation. The effect of copper on these silver losses has been studied and a "copper limit" for cupellation has been determined. Scorification and crucible fusion procedures for copper-bearing materials have been designed so that the lead buttons produced will not contain amounts of copper greater than this determined copper limit. Silver losses during these crucible fusion and scorification procedures are given by the distribution law, and can be calculated. Thus, silver can be determined in copper-bearing materials with a satisfactory degree of accuracy provided that the appropriate corrections for losses are applied to the weight of the silver prill produced.

Jan 1, 1957

Economically significant gold-silver mineralization occurs in Miocene andesitic flows and tuffs at Golden Cross, eight kilometres northwest of Waihi, New Zealand. The highest grade mineralization occurs in a steeply dipping elongate zone of strong quartz veining and brecciation underlying, but contiguous with, a gently dipping tabular quartz vein stockwork containing potentially open-pittable lower grade gold-silver mineralisation. The stockwork zone is enveloped by argillic alteration and overlain by unaltered Pliocene andesites and recent tephra. Evaluation of the prospect involved underground and surface geologic mapping, rock and soil geochemistry, IP-resistivity, magnetic and gravity surveys as well as 1844 metres of reverse circulation drilling and over 30 000 metres of core drilling. The paper outlines the exploration history of the area and describes the results of the various exploration techniques used at Golden Cross.

Jan 1, 1986

By S A. Myers, T Klein

The Yanacocha mining district is located in the northern Andes of Peru. The project is within the Cajamarca province, 20 km north of the town of Cajamarca and 600 km north of Lima, the capital of Peru (Figure 1). The district encompasses an area of 120 km 2 and is centred on the 78030'west longitude and 7000' south latitude. The project lies at an elevation of 3400 to 4200 masl.

Jan 1, 1999

By J Cook

In this paper we present a case study of the challenges and opportunities associated with the development of cultural heritage management strategies at the Lihir gold mine in Papua New Guinea. We discuss the contextual drivers and constraints, and outline the ways in which Lihir Gold Limited is aiming to set new industry bench marks for the region through the development of values-based best practice cultural heritage management programs. This approach is largely based upon a compliance partnership with a local stakeholder group. We argue that such partnerships are a prudent means of mitigating company risk, while constituting a far more necessary tool for local people in the reconceptualisation and negotiation of the experiences of significant social change and modernisation experienced in the context of recent resource development.

Jan 1, 2009

The mining industry in Australia frequently uses the services of specialist engineering and managing contractors and consultants for a majority of the work required for project development, from feasibility studies to project commissioning. The project owner's prime objectives are to achieve predictability and competitive advantage for their project. As the majority of this work will be carried out by contractors, the effective evaluation, selection and management of these contractors in the most appropriate forms of contracts is an essential ingredient to project success. The first stage to project development should be for the owner to examine its own resources to establish the role that it will fill and thereby identify the role and scope of contractors' involvement. Once the owner has developed this work plan, the selection of contractors and consultants should be structured to ensure that the owner acquires the appropriate expertise and experience to achieve its project objectives. The sequence of selection procedures is: 1. Pre-qualification of prospective contractors according to the owner's adopted criteria, through the use of a pre-qualification questionnaire. 2. Evaluation by the owner tender board according to predetermined mandatory criteria. 3. Preparation of tender documents for submission to qualified contractors. 4. Evaluation of tender submissions by the owner tender board using a pre-determined, weighted matrix of technical and commercial criteria. 5. Final selection and contract negotiation.

Jan 1, 1990