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In a coal mine there are many substances capable of ignition under certain circumstances, which can be placed in the following groups: ordinary combustible solids, dusts, liquids and vapours, gases, metals and plastics. There are many factors influencing ignition, including temperature, minimum ignition energy, particle size, explosion pressure level, rate of pressure rise, specific energy content and also explosive limit. Not all are applicable in every case. Frictional ignition of methane is an accident statistic of increasing concern and is considered in some detail. Practical measures that can be taken to reduce the incidence of frictional ignitions are considered, and also possible ways of ignition suppression.

Jan 1, 1981

The mineralogy of the crocidolite (blue asbestos) veins at Wittenoom Gorge was examined to determine the cause of failure to recover soma of the fibre by the ore-dressing methods currently being practised. As a, result of this yamina.tion, several fo.Ctors pertinent to the problem were found to be a function of the pa.ragenosis of the veins. The occurrenceof magnetite from tho'cap rock within the veins was thought to be preventing fiborisation during troo.tment. Several petrologic features are described and their relation to the ore genesis is discussed, Comparison with the crocidolite deposits of the Union of South Africa is also considered.

Jan 1, 1963

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

By Donchak P. J, Champion D. C, Fordham B. G, Domagala J

The Hodgkinson Province forms the northern part of the Tasman Orogen and contains the most extensive outcrops of Silurian - Devonian rocks in Queensland. Deep-water, marine siliciclastic sequences (mainly turbidites) dominate most of the province except near the western margin where mafic volcanics and fossiliferous limestones characterise much of the succession. It is difficult to apply normal stratigraphic mapping techniques to the Hodgkinson Province because of extensive stratal disruption by numerous thrust faults, the general lack of stratigraphic and structural markers, and the unfossiliferous nature of much of the succession. Nevertheless, several distinct units have been delineated although their internal stratigraphy or boundary or superpositional relationships are uncertain. Ordovician strata, as well as two major unconformities have been recognised in the western part of the province. Several models have been proposed to explain the evolution of the Hodgkinson Province. Although there is no general agreement most recent researchers favour an extensional tectonic regime.

Jan 1, 1990

By H Nikraz, E Jamieson, D Cooling

The use of red sand as fine aggregate in concrete manufacture has been investigated as well as the use of fly ash as a cement replacement. The experimental work consisted of casting various concrete mixes including a control and comparing standard properties. Properties tested included compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, water permeability, chloride diffusion, pH dependence leaching and particle morphology. The results show that the concrete strength is not significantly affected when natural sand is replaced completely with red sand. The durability tests indicated high water permeability and high chloride diffusion due to the porosity of the red sand concrete, likely due to the low slump value. Leaching tests did not exceed New South Wales EPA guidelines.

Jan 1, 2006

By Olson H, Kincaid R

The marine portion of the Pacific Basin and Rim constitutes a significant part of the world's surface in which the mineral resources are virtually undeveloped. Indications of substantial resources have resulted in speculation and uncertainty with regard to their potential in the near term. The main issues are centered on the markets for the resource materials, the technology needs for their recovery, and the possible impacts of their development on the environment. While the governments of Japan, France, the Soviet Union, India, China, and Korea are financing new programs in deep ocean mining, the US is consolidating its early leadership by the continuation of NOAA's authority under the Deep Seabed Hard Mineral Resources Act and the Sea Grant Act, Interior's authority under the outer Continental Shelf Lands Act, and by the development of a new Marine Minerals Technology Center within the Department of Interior's mineral institutes program, managed by the U.S. Bureau of Mines. The Center has a Continental Shelf Division (CSD) located in Mississippi, and an Oceans Basin Division (OBD) located in Hawaii. Research and training in the divisions is directed toward the practical aspects of mineral recovery from the nearshore and deep ocean environments with a strong bias for the OBD toward industrial and international cooperative programs in the Pacific Basin and Rim. In terms of resource development, the marine minerals in the Pacific Basin may be favored in some cases, in competition with land sources, by political and environmental considerations.

Jan 1, 1990

By J Williams

The recent drought has highlighted the finite nature of AustraliaÆs divertible water resources. According to AustraliaÆs recently completed National Land and Water Resources Audit, development of water resources in southern Australia has reached or exceeded sustainable extraction limits. Similarly, 161 out of 538 groundwater management units are either totally allocated or already over allocated. Whilst mining only uses about three per cent of diverted water resources, water scarcity may be a major factor that determines whether potential mines can be developed in the future. Furthermore, the development of extraction and processing facilities that limit water use and maximise the re-use the waste water streams will be even more fundamental features of the mining industry in the 21st century than they are at present. There are encouraging examples where innovative water re-use technologies are significantly reducing the water used per unit of mined product. Whilst mining in the areas of Australia draining to the tropical seas may be less constrained by a current lack of water (60 per cent of divertible water resources drain into the Timor Sea, Gulf of Carpentaria and north east Coral Sea), it is highly probable that there will be increasing demand for these waters from the irrigation industry, whilst pressure will also be applied to ensure that environmental flows that benefit the coastal fishing and prawn industries are maintained. In the Great Artesian Basin, current research is demonstrating that the groundwaters are being recharged at rates considerably lower than current extraction. Whilst some other groundwater basins in arid and semi-arid Australia have currently untapped resources, these water are often relatively saline and/or may be intimately linked with key ecosystems in discharge areas. This paper presents an overview of the current state of our water resources and examines some of the key water use issues including allocation, use and reuse, environmental flows and competing demands on the resource that will ensure that water issues remain high on the policy agenda for mining, irrigation and other water users.

Jan 1, 2003

By M Darby, B Burdett, F Lovell

The results of the process control improvement project aimed at improving the quality of Australian Bulk MineralsÆ (ABM) iron ore pellets produced by four vertical shaft furnaces are very positive. These results are achieved through process stabilisation and optimisation, improvement in process monitoring and taking early corrective actions when operating variables were outside the target ranges. A number of benefits are obtained from this project. These benefits include: More consistent and improved pellet quality. The average cold compression strength (CCS) value of pellets produced during the eight-month trial is 260 kg/pellet, which is 16 kg/pellet higher than that produced during the 12 months prior to the trial (244 kg/pellet). Reduction in the heat input by eight per cent, from 727 MJ/tonne to 668 MJ/tonne. Reduction in bentonite rate by six per cent, from 7.1 kg/tonne to 6.7 kg/tonne. Increase in the furnace throughput rate by four per cent and additional production of 10 000 tonnes per annum through process stabilisation. Better understanding of the process behaviour. This knowledge is valuable not only for setting the target operating conditions but also for developing the ABM expert system to control the process.

Jan 1, 2005

Someone once said "Leadership is the ability to inflict pain and get away with it." The same can be said about successful management of equipment suppliers. Improved performance will not be achieved without some pain, but it should be evenly spread between both parties. In practically all mining situations there is a great deal of scope for improving performance and reducing maintenance costs on an extremely wide range of plant, but it requires co-operative effort. Most mine maintenance engineers attribute the main problems to the equipment suppliers, unsuitable designs, lack of spares, untrained servicemen, lack of standardisation, poor maintenance manuals, and so on. Conversely the suppliers' engineers are usually convinced that problems with their product are exclusively due to poor maintenance management, after all they never have the same problem elsewhere. Of course both are correct to some degree. My aim in this paper is to explore the opportunities for substituting collaboration for confrontation between the engineers of the mining and supplying companies. I will also propose that contrary to common belief, the mines rather than the suppliers, should be taking the management initiative needed to achieve a closer and more effective relationship, Many would argue that this initiative should remain solely with the supplier; after

Jan 1, 1980

By E Topal

Risk and uncertainty are attached to mining projects, and making decisions, hedging, future investment and evaluation of mining projects depend on forecasting the future price. The future technologic developments in mining will be primarily influenced by the future commodity prices. A few approaches, with different confidences are proposed to predict price movement in the future. This research introduces a new comprehensive version of the mean reverting jump diffusion model for natural-resource commodity prices. The novel model proposes that the historical data of mineral commodities have three terms to demonstrate fluctuation of prices: mean reversion component, diffusion component and jump component. The model calculates each term individually to compute the future prices of mineral commodities. Subsequently, in the second section of the paper, the model is implemented for monthly historical data of gold price from January 1968 to May 2008. This research is investigating the relationship between the historical oil price and inflation with the gold price. This is followed by a future estimation of gold price fluctuations up to 2018. The results from the application of this new method are discussed in the context of how they accurately replicate the historical gold price and how they can predict the future gold price.

Jan 1, 2008

By T Tran, F Lucien

Supercritical fluids (SCFs) have gained recognition as solvents for the extraction of a wide range of organic materials. Their principle advantages over conventional organic solvents are that they possess much more favourable transport properties and that such properties can be easily altered by adjusting the system temperature and/or pressure. More recently, SCF solvents have been employed in the extraction of metal ions. The direct extraction of metal ions using SCFs such as CO2 is normally not possible due to the charge neutralisation requirement for solubilisation. However, extraction can be achieved with a SCF solvent containing an organic complexing agent as a cosolvent (Laintz et al, 1992; Laintz and Tachikawa, 1994; Dehghani, 1996). The role of the SCF is therefore similar to the role of a diluent in conventional liquid-liquid or solvent extraction processes. In this regard, SC-CO2 is a particularly good diluent since it exhibits good solubility for many organic complexing agents. The extraction of metals with SCF solvents has been examined mainly in the analysis of environmental samples and the treatment of metal contaminated wastes. Nonetheless, some interesting results have been reported recently on the extraction of rare earth metals, which highlight the potential of SCF solvents in mineral processing applications (Laintz and Tachikawa, 1994; Dehghani, 1996).

Jan 1, 2000

By M Castle, D Mendelawitz

The Marra Mamba iron ore in FortescueÆs Chichester Range project area occurs as a very flat dipping series of waste shale and iron ore beddings. These beddings vary from millimetre thickness to several metres. The ore material generally exhibits a moderate degree of competence when subjected to ultimate compressive strength (UCS) tests, normally failing at up to 60 Mpa. However, the strength of the beddings is markedly less when subjected to the tensile forces imposed by the cutting action of the surface miner. Two surface miners of differing age and sizes were tested over a period of almost three months. These machines produced a product that had not been subjected to dilution by blasting and of such a size that primary crushing is not required. The machines were able to cut all ferrous material presented to them with varying degrees of success. Material containing higher quantities of manganese were broken but caused catastrophic wearing of the picks. During the trial the volume of material produced by the two machines in various strength materials very closely matched the manufacturerÆs estimates. The major impact on costs per tonne related to the wear on bits, which in turn varied with the bit design and composition. Bit design and composition testing is continuing.

Jan 1, 2007

The word "optimization", refers to the search of an economic optimum, or, more precisely, to the choice of technical parameters which will define the more profitable mining project, knowing the values of the economic parameters. In fact, there is no direct way to perform this optimization, because the extremely large number of technical factors involved, from the type of working and its selectivity to the characteristics of the mill and its flexibility, makes it impossible to make a comprehensive survey of all possible projects. Beside, it would be meaningless to engage in such a task as the deposits themselves are not really known, but only estimated, with sometimes a high level of imprecision. Not to mention the numerical instability which would affect such a computation! In addition, the "best" project is not necessarily the one which strictly maximizes a given profit formula. There also exist human factors which have to be complied with, when choosing the cutoff grades for instance. Finally, there are other non-numerical factors which interfere with the choice between several projects: the shape of the bottom of a pit of the layout of the access road for instance.

Jan 1, 1986

The problem of manufacturing from sulphuric 'acid and Christmas Igland "A" phosphate, superphosphate of acceptable physical condition and agronomic phosphate availability, is directly related- to the crystallisation of a reac- tion product, monocalcium phosphate monohydrate. Two solutions to the problem, vacuum drying the superphosphate and calcination of the ore before reaction with acid, are discussed.

Jan 1, 1971

By R T. A MacGillivray, S B. Curtis

Bacteriophage (phage) are viruses that infect bacteria. Protein coatings on the surface of the phage particle can be genetically engineered so that they bind to inorganic molecules. The filamentous phage particle is about 930 nanometres in length and 6.5 nanometres in diameter and consists of a single-stranded molecule of DNA surrounded by five different coat protein molecules denoted P3, P6, P7, P8 and P9. Peptide sequences in the P3 coat protein that bind to sphalerite and chalcopyrite have been identified. The binding is selective; phage with specific P3 peptide sequences bind to minerals but do not bind to silica or to pyrite. Two peptide sequences in the P8 coat protein that bind selectively to chalcopyrite and pyrite have also been identified. The amino acids in the P8 binding sequences are hydrophilic and thus a coating of a mineral particle with phage having these peptide sequences may render the particle hydrophilic. Experiments are underway to confirm this. Phage are relatively easy to grow and are not living organisms requiring an energy source to maintain life. Phage can also tolerate a range of pH and temperatures. Given this, and the ability to indentify phage coat proteins that bind selectively to a variety of inorganic molecules, phage have the potential to be useful tools in mineral processing and waste treatment.

Jan 1, 2008

By F J. Rios

In the eastern high-strain domain of the Quadrilßtero Ferrffero, Brazil, hard and soft high-grade hematite ore may occur as schistose bodies in shear zones mainly related to the Cambotas-Fundpo thrust system. These orebodies are almost entirely constituted of oriented specularite platelets that develop both as a product of crystal-plastic deformation of hematite and solution-precipitation processes. Both mechanisms interact in the partitioning of the strain, while solution-precipitation is responsible for the precipitation of hematite and localised leaching of silica resulting in the formation of syntectonic ores. The analyses of fluid inclusions from specularite crystals of the Conceitpo and Timbopeba deposits, located in the northern and southernmost areas of the eastern high-strain domain of the Quadrilßtero Ferrffero, were studied using infrared microthermometry and Synchrotron x-ray fluorescence. The results indicate the participation of highly saline aqueous H2O-NaCl fluids containing other additional cations (Ca, Fe, K and probably Ti) in solution and homogenisation Temperature (Th) averaging between 130¦ - 190¦C. However, the partial fusion of metastable saturation phases indicates crystallisation temperatures of approximately 400¦C. The mineralisation process produces high-grade orebodies as well as Fe-rich specularitic itabirites that are explored in that area. The shear zones are related to thrust faults mapped and interpreted as related to the PanAfrican/Brasiliano Orogeny that affected the Quadrilßtero Ferrffero, thrusting the Paleoproterozoic platform sequence of the Minas Supergroup over Mesoproterozoic quartzites of the Espinhato Supergroup. They intersect and even overprint an early metamorphic and tectonic fabric of Paleoproterozoic age (Transamazonian Orogeny). The geological and fabric relationships lead to the conclusion that the fluids involved in the mineralisation were most probably of external origin, of still unknown source (possibly igneous), during the closure of the Spo Francisco Craton.

Jan 1, 2005

By E R. Ramanaidou, M S. Piggott

Transport to and handling of iron ore at Port Hedland, Western Australia, results in the generation of airborne particulates that contribute to the atmospheric dust load, with concerns about potential local environmental impacts (eg mangrove swamps) and possible human health implications. Mineral and chemical characteristics of the Background soil samples were contaminated with particles of iron ore as martite octahedra and grains of micro-platy hematite as detected by scanning electron microscopy (SEM) in the 2.5 - 10 ¦m and 10 - 50 ¦m size fractions. Fossilized wood fragments similar to those observed in Yandicoogina fines ore were also detected in some background soil samples. With a predicted increase in demand of channel iron deposits (CID) ores and the inherently dusty Marra Mamba ores (eg West Angelas, MAC, OB29/30/35, Marandoo), in conjunction with particulate emissions from hot-briquetted iron and direct reduced iron (HBI/DRI) processing plants, there is the potential for additional sources of anthropogenic dust to contribute to background levels. Mineralogical and chemical characterisation of the entire range of particulates that could be produced is necessary for a complete understanding of their potential impact on the local environment.

Jan 1, 2002

By T Kitajima, T Kawaguchi, T Nakamura

Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic iron production based on this mechanism, the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evaluated. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoxidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pellet size and so forth on the reduction/metallisation degrees of the samples after the reduction experiment. It also discusses the effect of pretreatment of the composite pellets using CaO bearing materials to suppress the reoxidation of formed metallic iron in the bed.

Jan 1, 2000

By Glenn R. J

Treatment processes are outlined for the recovery of rutile and zircon from the heavy mineral-bearing sands on the east coast of Australia. With the exhaustion of the higher grade deposits and the imposition of more rigid specifications for the finished products, strict metallurgical control has become necessary.A description is given of the methods used by The Titanium Alloy Manufacturing Co. Pty. Limited to control the operation of suction dredging, of wet concentration using fans and spirals, and of dry separation using high tension and electromagnetic processes. By applying these methods a plant designed for an output of 15,000 tons of rutile per year has been tuned to produce over 20,000 tons of rutile and a corresponding amount of zircon.Details are given of (a) the method of drilling to determine the extent and grade of the ore bodies, (b) a simple electrically-timed pneumatic automatic sampler, and (c) the methods developed for the physical estimation of quartz, rutile, zircon, ilmenite and "others" in the products of plant operation.The method used for calculating the metallurgical balance and the forms used for the reporting of production results are presented.Examples are given which show the value of this detailed production and metallurgical control of plant operation.INTRODUCTIONThe organization which is now known as "The Titanium Alloy Manufacturing Co. Pty. Limited" (T.A.M.Co.)-a subsidiary of National Lead Company-commenced operating at Yamba, N.S.W., in 1935. A mixed natural concentrate was at first simply dried and bagged and later was upgraded by the removal of silica and the lighter heavy minerals on shaking tables and, after air-drying, was bagged for export. At that time zircon was the most wanted constituent.

Jan 1, 1960

By Williams P. A

Tailings dams constructed by the upstream method have traditionally been built using the sand fraction of the tailings, which has automatically provided a relatively permeable embankment material, and helped provide the necessary drainage conditions which are a pre-requisite for safe and stable dam construction using this method. This paper discusses some recent trends which have resulted in proposals to use impermeable material in place of the sand fraction as the embankment material, both for the starter dam, and subsequent lifts. The consequences of these types of decisions on the overall stability of the dam are illustrated, and the need for continued monitoring of pore pressures in the tailings as the dam is raised is emphasised.

Jan 1, 1992