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Production scheduling is an important element of the mine planning process. The production schedule specifies the quantities of mineral to extract, the source of this ore, the timing of extraction and, where necessary, the quantity and timing of backfill placement. These details are important in linking long-term strategic goals to short-term operational planning. Mine scheduling techniques form the basis for communicating information concerning the overall impact of design and planning changes to a wide range of people at many levels within an organisation. Consequently the techniques used for mine scheduling must support the decision-making process by consistently providing high quality schedules in response to revised and updated data. A new mixed integer programming (MIP) model has been developed to generate optimal production schedules for underground stoping operations. The model maximised the before-tax Net Present Value of the production schedule while satisfying constraints such as contained metal tonnage, hoisting capacity, stope geometry relationships and stope backfilling demands. Zero-one variables were used to represent the decision to extract or backfill each stope in a particular time period. Continuous variables, capable of having non-integer values, were used to denote the quantity of ore or backfill associated with a specific stope in a given time period. A case study is presented to demonstrate the significant improvement in before-tax NPV over a comparative manual production schedule in a large underground mine. The MIP model allows for further modification to reduce solution times and meet the needs of individual mines.

Jan 1, 1995

Autocompression and virgin rock tempera ture have a marked influence on the ventilation of the lower levels at North Broken Hill Limited N.S.W. To maintain comfortable working temp- eratures without penalty to working hours, increase in airflow or the cooling of the work area is necessary. The use of refrigerated air cooling is discussed. Ventilation of underground mining opera tions at North Broken Hill Limited is accomplished by downcasting air through No.3 shaft, the main operating shaft, 1581 m deep, with additional air through No.1 shaft (542 m) 2 and No.2 shaft (978 m), both no longer opera- tional shafts. Air is upcasted through No.3 ventilation shaft which is 4.9 m diameter and concrete lined, from the No.28 level (1140 m) to the surface. On the surface level of this shaft is a horizontally mounted Richardson 4800 mm diameter single stage axial flow fan with adjustable pitch rotor blades.

Jan 1, 1977

By Fuerstenau DW

The flotation of pyrite in ethyl xanthate solutions is presented along with electrokinetic results. The results have been analysed in view of recently published thermodynamic calculations as well as other published data on the pyrite-xanthate system including adsorption and voltarnmetry studies. The flotation response of pyrite in xanthate solutions is characterised by two maxima, one at pH 4 and the other at pH 8-9. The acidic maxima is also associated with a reversal in the electrophoretic mobility of pyrite, probably due to the formation of ferric xanthate on the pyrite surface through chemisorption of xanthate ions while the basic maxima is not associated with major changes in the mobility and flotation at this pH can probably be attributed the adsorption of dixanthogen. It is concluded that there is not sufficient experimental evidence to conclusively attribute the lack of flotation response in solutions at near neutral pH to any particular phenomena, either kinetic or thermodynamic.

Jan 1, 1993

By K Karmawan, T Casten

The PT Freeport Indonesiaæs Deep Ore Zone (DOZ) copper deposit is located in the province of Irian-Jaya, Indonesia. Currently, a block cave mine is being developed around this deposit. Production is scheduled to start the fourth-quarter of year 2000 and to ramp up to 25 000 tpd by year 2003. The air quantity requirement for this mine is equal to 780 m3/s. To supply this quantity, the mine will require five centrifugal fans (one 450 and four 750 kW fans). This study summarises the technical aspects related to the installation and commissioning of two of these fans. The fans were installed on the surface in parallel arrangement with two others. Each has a design capacity of 240 m3/s of air at 2.2 kPa of static pressure. The study presents the installation details from the underground shaft excavation and portal development through fan testing and commissioning. It also presents the results of a monitoring system that was installed to determine the fan duties.

Jan 1, 2000

I offer some comments which might complement the valuable recent paper by De Angelis et al (1987), on the newly discovered nickel-copper deposit at Radio Hill.The authors have accepted subdivisions and correlations by Hickman (1977, 1983) although they are disputed (Fitton, Horwitz and Sylvester, 1975; Horwitz, 1979; Horwitz and Guj, 1986).Also, in my opinion, more plausible correlations of the Sholl Belt with Whim Creek Belt have been shown, but not discussed, in Hudson and Horwitz (1986, Figure 1). Our suggested correlations and subdivisions have appeared in publications and reports which are not readily available, but it is gratifying to note that many of the observations and conclusions of De Angelis et al are consistent with our conclusions of the Whim Creek Belt.The units of the Sholl Belt (of Hickman, 1983), between the Sholl Fault (Shear Zone) and the overlying Mt Bruce Supergroup to the south, equate well with units of the Whim Creek Belt. A basalt, characterised by an abundance of vesicles and similar in many ways to the Wararnbi Basalt of Fitton, Horwitz and Sylvester (I975), is well developed at the base of the succession, particularly in the southern part of the area (Figure 1). It is overlain by acid tuffs (locally metamorphosed, such as at Whundoo Mine) and associated acid and mafic lavas, similar to those of the Mons Cupri area. The mafics in the succession are marked by the absence of the numerous cherty sedimentary intercalations, such as the Marble Bar Chert, which occur in the Warrawoona Group; and they also lack the intense chertification that is prevalent in all parts of the proven areas of Warrawoona Group rocks.The Whim Creek Group is overlain, locally unconformably (two to three km east of Mount Negri), by the Negri Volcanics which include here the Louden Volcanics (unit Abu of Hickman, 1977), (Horwitz, 1979). The negri volcanics are an alternating sequence of variolitic and quench textured lavas not dissimilar to the highest units of the Sholl Belt (Figure 1). They range from high-Mg basalt to tholeitic andesites (Glikson et al, 1986, pp 79 and 84). The whole succession of the Sholl Belt is estimated to be of the order of four km in thickness, more consistent with the two km thick (Horwitz, 1979, Figure 1) Whim Creek area sequence than with the much thicker Warrawoona Group sequences. The Whim Creek Group (including the Negri Volcanics) is considered to be a widespread grouping (Fitton, Horwitz and Sylvester, 1976; Horwitz, 1979; Horwitz and Guj, 1986) which is prevalent in the northern part of the Pilbara Craton. It is considered by these authors to include the Mallina Formation turbidites of the trough area of Ryan (1965). One component, the Mons Cupri Volcanic, is about 2.95 Ga (Richards and Blockley, 1984). Between the Sholl Fault and Egina, the Whim Creek Group is intruded by large ultrarnafic to granophyric ills of the Millindinna Complex (Fitton, Horwitz and Sylvester, 1975), dated at 2.860 ± 002 Ga by Gulson and Korsh (1983) near the Sherlock River (south side of Caines Well Granite area). The Millindinna Complex has been equated to the same magmatic episode as the layered complexes of the Sholl Belt by Fitton, Horwitz and Sylvester (1975, p 20).

Jan 1, 1988

ALTHOUGH discovered as long ago as 1817, by Strohmeyer, the use of cadmium did not become in anyway general for nearly a century. Its properties, although well known, did not recommend it to users of metals generally, and it was, on the whole, regarded more in the light of a nuisance to zinc producers than anything else. Its real value was not appreciated until both the United States of America and Germany, who are entirely dependent on outside sources for their supplies of tin, were faced with the unpleasant fact that their tin stocks were being rapidly depleted, with practically no prospect of having them replenished. This resulted in serious efforts being made in the UnIted States of America to conserve what tin was available, and, as a consequence, several metals were tried in the hope that they would prove satisfactory substitutes for tin. Among these was cadmium, and it was found that cadmium could replace tin in a manner sufficiently satisfactory to permit of its use in many directions where tin had been used before.It is on this ability of cadmium to replace tin that its use became in any way general at first; but since then new avenues of development have been opened up in which its physical and chemical properties are proving their value. It is highly probable that its use will extend very considerably as time goes on. OCCURRENCE OF CADMIUM.There are several cadmium minerals known, but none of them occur in profitable quantities as ores. The cadmium of commerce is derived almost entirely from zinc minerals and ores in which it is almost invariably present in proportions which are usually very small. Cadmium behaves metallurgically almost the same as zinc, and hence constitutes a fraction of 1% of almost all spelter.

Jan 1, 1923

By L Lagoeiro

The samples studied in this paper were derived from the iron oxide facies of iron formations (IFs) of the Quadrilßtero Ferrffero, south-eastern Brazil. The rich-iron oxide varieties of the IFs can be regarded as Fe-O systems because they consist predominantly of aggregates of haematite and magnetite crystals. The study was based on carefully selected samples in which magnetite crystals occur as isolated large crystals set in a matrix of haematite grains. Optical microscopy and an electron microscope equipped with an electron backscattered diffraction (EBSD) system were used to investigate the microstructural and crystallographic relationships involved in the phase transformation between magnetite and haematite. The magnetite crystals in the IF samples are partially transformed to haematite and this process is also known as martitisation. This transformation occurs along the crystallographic planes {111} of the magnetite producing a characteristic triangular pattern of interlocking lamellae of transformed haematite crystals that are oriented parallel to octahedral plane {111}. This new generation of haematite is referred to martite because of the martitisation process. EBSD analyses show that the magnetite and the new haematite crystals, martite, share crystallographic planes of highest atomic density, eg {111} and (0001), respectively, possibly due to the ccp and hcp atomic arrangement of the two crystals. Stereographic projections of these two planes therefore coincide when the maxima of their poles are plotted. However, the crystallographic orientation of the haematite crystals in the matrix shows maxima of (0001) poles that do not coincide with those of {111} planes of magnetite. Consequently, it is concluded that the direct transformation to haematite crystals retains the crystallographic orientation memory of the former magnetite crystals, possibly due to the similar manner whereby their atoms are packed together in the crystal structures. On the other hand, no such relationships are observed between magnetite and haematite crystal in matrix. This suggests that haematite grains in the matrix may have been formed by other processes rather than those involved in the iron oxide transformation observed within the magnetite grains.

Jan 1, 2008

Investigations of the Mineragraphic Section; Commonwealth Scientific and Industrial Research Organisation, have included most of the known stannite-bearing ores in Australia, and have revealed several new occurrences of this relatively uncommon mineral. They provide information about its paragenesis, and its possible effect on tin recovery, that may be of general interest.Several of the investigations used in the preparation of this paper, were made in the first instance by pr. F. L. Stillwell or in collaboration with him.CASSITERITE-SULPHIDE ORES IN NORTH-WEST- TASMANIA Stannite is a minor component of most of the cassiterite sulphide ores of north-western Tasmania. These include the orebodies of Mount Bischoff, the Cleveland mine, Moina, the Stanley River district, Renison Bell, and the Heemskirk-Zeehan district, and form a well defined metallogenetic provence which is related to the Devonian granites of this part of Tasmania.In these ores mineralisation began. with deposition of cassiterite, a little wolfram, and quartz, topaz and tourmaline. With falling temperature, deposition of cassiterite ceased and arsenopy-rite, pyrite, and especially pyrrhotite, formed in abundance, tending to give massive sulphide ore. A little chalcopyrite; stannite, sphalerite and native bismuth accompanied the pyrrhotite. Deposition of quartz ceased after the pyrrhotite, was formed, and the later-formed nonsulphide gangue consists chiefly of carbonates and fluorite. With, the advent of the carbonates the pyrrhotite was altered to fine-gained intergrowths of marcasite and pyrite. Excess iron from the pyrrhotite entered the intergrown carbonate, or was precipitated as magnetite. Some solution of the cassiterite occurred at this stage, the tin being redeposited chiefly as stimnite replacement rims around the residual cassitellrite grains. Varying, but small, amounts of sphalerite, galena, tetrahedrite and silver minerals were depoSited at this stage, bringing the mineralisation to a...

Jan 1, 1951

By Eoffe SW

The wide application of computers in beneficiation plants has resulted in the creation of a number of complex automatic control systems at all stages of ore dressing processes. To create such systems it is necessary to solve complex problems of analysis and calculation. The application of computers to solve these problems demands development of simple and effective methods of investigation and simulation of ore dressing process dynamics because all the known methods are complicated in usage and cannot guarantee the desired accuracy and quality of process control. A new grapho-analytical method of investigation and calculation of ore dressing flow sheet dynamics, worked out by the authors of this paper, is based on proportion method development and is used to construct dynamic characteristics of the investigated processes. It is possible to use the given method for investigating benefication schemes with flotation machines having non-linear static characteristics and circulating loads. The suggested method of investigation of concentration flow sheet dynamics allows us to obtain dynamic characteristics of technological process parameters in both linear and non-linear systems. Moreover, the final result can be obtained without labour consuming analytical calculations by a simple graphical construction based on the static characteristics of the known equipment and processes.

Jan 1, 1993

By J Chen

Research conducted into backfill drainage at Mount Isa Mines since 1992 is described. Piping in draining backfilled stopes has been the primary cause of bulkhead failures and emphasis is placed on research into the piping mechanism. Laboratory and in situ tests aimed at understanding the piping mechanism have been conducted and the results are presented. A case history of piping in a draining bench stope fill mass is described and a technique for reducing the potential for bulkhead failures in bench stopes is presented. Hydraulic fill is produced by standard cycloning of tailings and the overflow (reject material) is sent to thickeners prior to placement in the tailings dams. Research into the partial introduction of thickener underflow into the backfill system and its influence on backfill drainage is also described.

Jan 1, 1998

By C Robertson, J Campos

The South African mining industry first experienced en-masse use of electronic detonators in the Narrow Reef environment using AELÆs ElectrodetÖ pre-set delay system. In recent years, programmable systems such as AELÆs SmartdetÖ have also established their position, and within both AEL and the mines there has been important learning around the strengths and weaknesses of these systems. In general, the fixed delay systems tend to be more easily appreciated by less-skilled work teams, and are very well suited to simple layouts, especially long, narrow blasts. However, development of programmable row controllers and series delay inserts has greatly expanded the field of usefulness of these systems while retaining most of the simplicity of use. The programmable systems are immensely flexible and therefore able to function under any condition, but require a higher level of discipline and knowledge. Much has been done to address this issue and make the systems user friendly, so the systems have converged to some extent. These systems are both valuable tools for achieving control over blasting in underground and surface applications. The choice of system is very dependent on the prevailing conditions. Accurate timing with electronic enhancements continues to show an increasing range of benefits to mining operations. There is a strong parallel with non electronic initiation systems which helps to understand the appropriate use of the systems.

Jan 1, 2001

By Taylor R. K A, Berglin C. I K

The manganese ore deposits at Groote Eylandt are quite variable both in regard to grade and physical cond- ition. In order to treat a wider range of these ores and to increase production a new primary-crusher and' concentrator complex costing $8 million has been installed and commissioned to treat ore at the rate of 12,000 tonnes per day. The initial testwork carried out to determine the method of the ore treatment required, and on which the design of the concentrator was based, is detailed. The flowsheet and equipment used is discussed together with the operation of the plant. The production achieved and product qualities obtained are given.

Jan 1, 1973

By Orr T. O H, Hodkinson I. P

The Mount Leyshon breccia complex is located on an east-west trending contact between Cambrian metasediments (Puddler Creek Formation) and the Ordovician Mt. Leyshon granite, within the Lolworth-Ravenswood block. Detailed mapping of basement, breccia and igneous unit geometries, crosscutting relationships and resolution of complex chronological relation- ships indicates that the Mt. Leyshon breccia complex should be reinterpreted as a number of intrusive igneous and breccia phases. This is in contrast to a previously published account of a largely extrusive geological setting. A complex structural history dominated by strike-slip faulting is preserved within the basement units and is responsible for controlling the location and geometry of the breccia complex. The breccia complex has been divided into brecciated "basement", "main pipe breccia" and an "interactive magma/breccia sequence". Main pipe breccia (the most voluminous unit within the complex) has been re-interpreted as an intrusive breccia, rather than an extrusive or vent fill as previously proposed. This is based on the following evidence: 1. the facies characteristics of the main pipe breccia, 2. the presence of a progression from cohesive basement through to mixed breccia, 3. minor basement block rotation during breccia complex formation, and 4. the partial structural control on the main pipe breccia. No unambiguous evidence exists for pyroclastic facies, although the fine breccia variant commonly contains "accretionary structures", very similar in appearance to those formed during pyroclastic processes. In view of 1. above, they are interpreted to be the product of particle accretion during upward movement of fragmental material, although an origin due to altera- tion cannot be completely discounted. heir occurrence in the main pipe breccia indicates that their presence within a rock unit is not necessarily diagnostic of nvroclastic nroeesses.

Jan 1, 1991

By Gillies A. D S, Just G. D

The advancement of computer applications in the coal industry is focusing interest on the presentation of washability data by mathematical functions.The normal method of presenting washability data is in the form of five curves, usually filled by eye or by cubic spline functions. It has been shown that coal washability can be characterised by two basic relations: the instantaneous ash vs relative density relationship and the instantaneous yield vs relative density relationship. In a new approach to the mathematical modelling of the instantaneous ash vs relative density relationship, theapplication of the algorithm to a data set from a mine in central Queensland was successful.

Jan 1, 1991

The passage of a vast array of new State and Federal environmental legislation over the last couple of years has required many mine operators to sharpen their focus on environmental requirements. Established requirements, such as environmental impact assessment, minimising disturbance and rehabilitation must now be complemented by mine environmental management plans. These may not only require regular monitoring of mine operations and detailed forward planning to prevent or reduce environmental harm caused during mine operation, but annual updating. It is likely that in future these plans will be required to incorporate general principles such as pollution prevention, sustainable development, waste minimisation and conservation of biodiversity and ecological integrity.

Jan 1, 1993

By Milner E. F

Thallium is largely volatilized during sintering in the conventional sinter/blast furnace production of lead. The new direct oxygen smelting processes will force the thallium into the bullion, necessitating a means of removal to avoid contamination of the refined lead. Pilot plant testwork demonstrated that thallium was efficiently removed from lead bullion by treatment with molten zinc chloride. The spent zinc chloride salt was treated in the laboratory to recover lead sulphate, a zinc chloride solution, and a thallous chloride salt containing over 80% thallium. Cominco is installing this thallium process as part of its Trail Lead Smelter Modernization Program which will commission a QSL bath smelter in late 1989.

Jan 1, 1989

By Mernagh T, Large R. R, Ryan C. G, Huston D. L

The Tennant Creek goldfield is one of the largest gold producing districts in Australia, and major deposits, including Gecko, Juno, Orlando, Peko, Warrego, Nobles Nob, Golden Forty, Argo, TC 8 and White Devil have produced more than four million ounces of gold over the past two decades. Gold-copper-bismuth mineralisation at Tennant Creek occurs in lenticular, ellipsoidal or pipe-like bodies of magnetite-hematite ironstones which are hosted in turbiditic sedimentary rocks of Proterozoic age (Large, 1975; Wedekind, Large and Williams, 1989; Le Messurier, Williams and Blake, 1990; Morrison, Donnellan and Hussey, 1992).

Jan 1, 1994

By T Klinge, P Field, N Sugden, D Trenberth

Mining remains one of the key industries in Australia and many other countries with mineral wealth. In Australia, mining contributes 8.8 per cent to the countryÆs gross domestic product (McKay et al, 2000). In Queensland alone, mineral and petroleum industries contribute approximately $9.4 billion to the StatesÆ gross state product (2001/02) (Young, 2003). Increasing pressure on mining companies to perform in a global marketing environment requires mine management to consider more innovative ways to manage their resources û human, plant and equipment û which includes the gathering and analysis of operations data and information for improved decision making. For any mining operation utilising rubber tyred equipment such as trucks, front-end loaders and ancillary equipment, annual expenditure on tyres and related items can be significant. Even a small reduction in tyre operating costs can have a real effect on the business bottom line performance in the short term. Tyre Application Risk Management (TYREARMÖ) can provide substantial benefits in the long term across a number of KPIs not just through reduction in direct tyre expenditure but through flow-on improvements in safety, productivity and reduced environmental impacts. Several accidents involving tyres have also highlighted an increased need to consider the hazards and resultant risks arising from operations of rubber tyred mining fleets (Torlach and Johnston, 1990). This paper presents the process and results of achieving sustained safety and business improvement through the strategic alliance between an earthmover tyre management service provider, Klinge and Co (Klinge) and a BHP Billiton coal mine. The accompanying case study demonstrates in some detail the overall methodology, and the tools and technologies used where active management of data, its analysis and decisions taken have resulted in a 43 per cent improvement in tyre cost performance and a corresponding reduction in tyre-related downtime since the beginning of the alliance.

Jan 1, 2003

Oxy-ACETYLENE system of welding and cutting is at present practised in two forms, which may be described as the high and lowpressure systems. In the high-pressure system the two gases, oxygen and acetylene, are delivered. to the blow-pipe under pressure from properly constructed trade cylinders. Oxygen cylinders are in two sizes, each containing 100 and 200 cub. ft. of gas respectively. These cylinders are charged to a pressure of 120 atmospheres, or 1800 lb. per sq. in. approximately. The acetylene cylinders are made in one size as far as the writer knows, and contain 200 cub. ft. of acetylene gas at a pressure of 10 atmospheres. Each cylinder is provided with a valve and connection for attaching a regulator to "break down" the high pressure in the cylinders to the necessary low working pressure of the blow-pipes, and to deliver the two gases at a constant pressure irrespective of the variable pressures in the cylinders. These regulators can be adjusted down to as low as 1 lb. and are provided with two pressure gaugesone reading the contents of the cylinder in atmospheres, and the other the working pressure in lb. per sq. in. The high-pressure, or "two cylinder" system is compact and can readily be transported from place to place in the works. For this purpose the two cylinders are mounted on an easy-running 4-wheeled truck, which the operator and assistant find no difficulty in manipulating. In the low-pressure system the two gases are delivered to the blow-pipe, one from the oxygen cylinder and the other from the acetylene gas generating plant, which consists of the following:Generating cylinder, half filled with water, into which the cathoide is plunged. The generated gas is passed through a filter to the gasometer, then through a water washer on to the hydraullic seal...

Jan 1, 1922

By K Hskansson

In earlier studies along a mining region recipient (the river VormbScken, northern Sweden), the fraction of certain trace metals recovered in the particulate phase has been found to increase with increasing concentrations of particulate iron. This study was conducted to see if the pattern could be reproduced by adding minor amounts of ferrous iron, simulating groundwater inputs. When the iron is oxidised in the near neutral river water, it will form iron oxyhydroxides and precipitate. Trace metals may be either co-precipitated along with the iron, or adsorbed onto the freshly formed precipitates. If this is the case, such a mechanism may be incorporated as a part of a final polishing step in a mine drainage treatment system based on natural attenuation processes. The experiments were performed at 0¦C and 22¦C, on authentic river waters collected during the winter and summer of 2002, respectively. In order to investigate the influence of particles and bacteria initially present, filtered river waters (4 solution were added to the experimental beakers, increasing the iron content of the waters by 0 - 1.5 mg/L. The oxidation and precipitation processes were followed by means of filtration (0.2 ¦m) for up to seven days. In order to be able to compare the experimental results with the actual field situation, on both experimental occasions, surface water samples were collected also from three stations situated along the river. The samples collected were analysed for iron, calcium, and trace metals by AAS and ICP-MS. The iron oxyhydroxides formed in the experiment did not influence the partitioning of As, Cu, and Pb to the same extent as the particulate iron encountered along the river appeared to do. Cd and Zn were recovered mainly in the dissolved (

Jan 1, 2003