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By Hutchinson IN

In order for the Australian underground coal mining industry to achieve the high productivity rates demanded of it without compromising its good safety record, improved geotechnical monitoring systems are required. One of the main problem areas affecting underground coal mining is the deterioration of previously stable roadways.CSIRO Division of Geomechanics has been working on a NERDDC funded project to develop an instrument to monitor coal mine roof deformation. The instrument which has been developed, Roof Alert, is a self contained, battery powered, intrinsically safe device. It can monitor the magnitude and rate of deformation and give multiple, variable visual alarm signals where preset levels ate exceeded.

Jan 1, 1991

By M Ben, P de Donato, M Kongolo

The extensive literature on sulfide flotation indicates that pyrite poorly floats under alkaline condition. Xanthate concentration has a positive effect on pyrite flotation, but above a pH of 11, pyrite seems to be strongly depressed, independently of the concentration in xanthate. In this investigation, aeration and xanthate concentration effects were studied for pyrite flotation conditioned at pH 11 with lime. Results presented in this paper include surface infrared analyses and pulp chemistry measurements which have showed that aeration had a dual effect on pyrite flotation. It induced pyrite surface activation by oxygen, and oxidation of ferrous iron to ferric hydroxides or oxyhydroxides species. It also favoured dissolution of CO2, leading to calcium carbonate precipitation and adsorption onto pyrite surface. Both CO2 dissolution and ferrous oxidation generated protons and decreased pulp pH. Pyrite flotation was observed to be effective with a statistical monolayer of xanthate that could be adsorbed as mixture of dixanthogen and metal-xanthate complex. Non-floated fractions showed high amounts of carbonate, and presence of hydroxyl iron sulfate (Fen(OH)m(SO4)p, xH2O) which have inhibited the hydrophobicity effect of adsorbed xanthate. Environmental desulfurisation could be improved by aeration control causing pyrite oxidation and pH decrease to reach optimal flotation condition with a relatively low xanthate concentration.

Jan 1, 2005

It is generally known that Charters Towers was discovered by Mosman, Clarke and Fraser in 1871. However, the time was ripe, and these three were barely in front of others. There is one account that prospectors from Ravenswood visited the area months before but decided it was too far from water, and that one of them had told Mosman and party of the find. There is another account that Joe Larkins found the discoverers before they had registered any ground - this may explain Mosman's quick departure for Ravenswood.When the news spread, the rush was rapid, and there was soon a sizeable population: probably too many, as within twelve months the infant settlement was under considerable stress. First, the presiding Gold Commissioners had adopted "unusual and arbitary" interpretations of the Regulations, and many of the miners were aggrieved; Charters, the senior Commissioner, was accused of favouring moneyed interests, and of retiring ill whenever a brawl or confrontation occured. As a result, the law of the field soon became "the survival of the strong". Second, the settlers were, divided on where the main town should be: Millchester, near the water, or Charters Towers near the mines. Third, the discovery of gold at the Millchester Deep Lead in August, 1872 was followed by highly exaggerated accoants in_' the southern papers, apparently fabricated by local business speculators. The resulting rush resulted in hundreds of unlucky prospectors having to return or seek other fields. In that period two men were killed in squabbles over ground. To make matters worse, by October 1872 a drought had set in, water cost three pence a bucket, fodder was scarce, cartage expensive, and the price of crushing ore rose to thirty shillings per ton.

Jan 1, 1986

Titanium tetrachloride may be reduced to trichloride with hydrogen on a hot tungsten filament and other hot: surfaces. The effect of temperature, time and size of t.he filament on the rate of reaction has been studied. A laboratory unit for preparing a few pounds of trichloride at a time is described. The yield of trichloride is 2·2 - 2·4 gm/sq. cm. of hot surface/hour at 1,000°C. and the energy requirement 3'5-4 kWh/pound of trichloride produced.'INTRODUCTIONThe lower chlorides of titanium (titanium tri- and dichlorides) are amenable to electrolysis, being electrovalent in nature. Furthermore, relative to other oxygen-free titanium salts, they are easy to prepare in a pure state and their use has been investigated to prepare titanium. The experimentaJ work described in this paper deals with the preparation of titanium trichloride by reduction of titanium tetrachloride with hydrogen on hot surfaces.REDUCING AGENTS FOR TITANIUM TETRACHLORIDEThe free energy diagram (Fig. 1) for the formation of chlorides suggests that titanium' tetrachloride may be reduced to trichloride by various reducing agents such as aluminium, zinc, arsenic, antimony, tin, mercury, silver, hydrogen, sodium, potassium and magnesium. Ruff and Neumann (1923), Thorpe (1885) , Billy and Brasseur (1935) and Seurbert and Schmidt (1892) used various metals to reduce tetrachloride to trichloride and found that the yields were invariably low and the products difficult to separate.Besides the metallic reducing agents, hydrogen may also be used to reduce titanium tetrachloride to trichloride.Goerges and Stahler (1909) obtained a deposit of violet...

Jan 1, 1956

By A V. Nguyen

Spherical calcium dioleate particles (~10 ¦m in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has longer range than DLVO (Derjaguin-Landau-Verwey-Overbeek) prediction. The repulsive AFM force between the calcium dioleate sphere and the fluorite surface does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at fluorite- and calcite-water interfaces as revealed by the numerical computation experiments using molecular dynamics simulation.

Jan 1, 2005

During the past decade geopolymer technology has emerged as a possible solution for the effective stabilisation and solidification of waste materials. Amorphous to semi-crystalline geopolymers form by the co-polymerisation of individual alumino and silicate species, which originate from the dissolution of silicon and aluminium containing source materials at a high pH in the presence of soluble alkali metal silicates. It has been shown previously that geopolymerisation can transform a wide range of waste alumino-silicate materials such as fly ash and blast furnace slag into building and mining products with excellent chemical and physical properties, including high compressive strength as well as fire and acid resistance. These chemical and physical properties suggest that geopolymeric matrices derived from waste materials are well suited for environmental and other applications such as the encapsulation of mine tails, the immobilisation of heavy metals and also the fabrication of structural products. The current challenge is to demonstrate that a wide variety of natural Al-Si minerals could serve as potential source materials for the synthesis of geopolymers. Moreover, it should be shown on a large commercial scale that it is possible to encapsulate waste materials into the geopolymeric structure without compromising the chemical and physical properties of the final product for the desired application.

Jan 1, 2000

Laboratory scale simulation experiments show that the adsorption capacity of Au(CN)Z- on activated carbon in the presence of organic plant contaminants is dependent on the particle size of the carbon. This observation suggests that fine carbon in a CIP contactor can protect coarse CIP carbon from fouling in a dirty CIP plant. A preliminary test of this concept was made using fine lignite coal as the organic scavenger in the presence of the CIP carbon Calgon GRC22 in an alkaline cyanide solution containing Teric 401, sodium ethyl xanthate and kerosene.

Jan 1, 1991

To counter depressed world nickel prices, a continuing effort is being made at Kalgoorlie Nickel Smelter to reduce unit production costs. One major area in which production costs can be reduced is the substitution of coal for fuel oil. Two areas where this has been achieved to bring about a saving are, the addition of coal to flash furnace flux to reduce supplementary fuel oil requirements in flash smelting and the replacement of two oil-fired air preheaters with a coal-fired unit. These actions have resulted in coal replacing 67% of the current fuel oil requirement in flash smelting at the Kalgoorlie .Lckel Smelter.

Jan 1, 1987

Prospecting in arid terrain can produce substantial environmental impacts, comparable to or greater in magnitude than the impacts associated with actual mining or petroleum production. Impacts are likely to be particularly severe where prospecting involves intensive geophysical exploration, especially in areas which have escaped degradation by other land uses such as pastoralism. With appropriate environmental planning and management, however, the environmental impacts of prospecting in arid terrain can be greatly reduced and mitigated, at low cost. In many countries, prospecting licences, exploration leases and associated tenements now carry a range of conditions relating to environmental protection. The assessment, avoidance and mitigation of environmental impacts is therefore an important component of and-zone exploration. My aim here is to give an overview of some of the main aspects of an environmental planning and management (EPM) programme for prospecting in arid terrain (PAT). Detailed operational prescriptions for environmental protection procedures are necessarily specific to particular areas and types of prospecting: see. e.g., Buckley (1982a, 1984, 1985a, 1986a), Klepacki et al. (1985) and Stone (1986). The intention here is to provide a checklist rather than a recipe book: as an aid in incorporating environmental aspects into the overall planning and management of an exploration programme, and in liaison with company environmental staff, consultants and regulatory bodies. I also hope to show that whilst some of the techniques used in particular environmental disciplines certainly require specialist expertise, the overall design of an EPM programme is not in the least esoteric, but simply an exercise in straightforward common sense. Perhaps this paper could be subtitled: "Demystifying environmental Planning".

Jan 1, 1988

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

By West Coast Staff

Attention to the design of facilities for drainage, of both surface water and seepage, made it possible to attain, for a qam impounding residues from a concentrating mill, a more stable sand wall which can eventually be carried to a greater height.EXPERIENCE WITH No. 1 DAMResidue from the lead zinc concentrating mill, which treats the ore from the Rosebery and Hercules Mines, was pumped 3,600 ft. through a 5-in. diameter woodstave pipeline to the site of the dam. It was formerly delivered through a 4-in. steel pipeline.State laws prevent the residue being discharged to waste into the Stitt River. Furthermore, as a pyritic residue it is a potential source of sulphur.Between 1936 and 1956 more than 1,000,000 tons. of residue was paddocked. The run-of-mill product was roughly classified at the dam in a 6-ft. diameter cone classifier and the sand fraction was pumped by a 3-in. pump to the front wall of the dam across a shallow valley. The overflow gravitated to the rear of the dam (Fig. 1). Typical sizings were:

Jan 1, 1958

By Davies S. G, Jayaweera A

The oxidation of nickel sulphide and copper sulphide concentrates, and coal, has been studied under non-ignition and ignition conditions using Differential Thermal Analysis (DTA) and Thermogravimetry (TG). The non-ignition reaction was favoured by slow heating rates < 10°C min-1), low masses < 10 mg) and an air atmosphere. Under these conditions, the typical stepwise oxidations of the various sulphide minerals present in the concentrate were observed as resolved exothermic peaks in the DTA curves and weight losses in the TG curves. Above a heating rate of 10°C min-1 , sample masses in excess of 10 mg and an oxygen atmosphere, an ignition reaction was induced, as indicated by a major high energy exotherm in the DTA curve and a major rapid weight loss in the TG curve. The ignition temperatures of the minerals under ignition conditions, found for 15 mg samples heated at 20°C min-1, were 434°C for the nickel sulphide concentrate, 372°C for the copper sulphide concentrate, and 230°C for the coal. By plotting a curve for mass against ignition temperature at constant heating rate and extrapolationto zero mass, a value of 470°C was obtained for the mass independent ignition temperature of the nickel sulphide concentrate. Ignition temperatures and extents of reaction at various temperatures were obtained using the TG technique in a novel manner which produced heating rates of 4500°C min-1. Under ignition conditions, the oxidations approximate to flash smelting conditions.

Jan 1, 1985

By A Scott

Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data û especially with semi-automated data acquisition by instrumented mine equipment. However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model. An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc not only have many areas of interest but also have very different conceptual models by which they evaluate performance. It is too ambitious to attempt to bring all of these cultures together û in a single step. However, the success of the Mine to MillTM project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from orebody model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling. However, in both cases the data collected is strongly focused on the technical requirements û not on the business model. This paper considers how to define at least some of the key decision points in terms of some case studies. Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning.

Jan 1, 2002

By Eldridge B. J

During recent years, Central Queensland has experienced a boom in its coal mining industry. This has involved many companies in projects requiring large capital expenditure. As with most projects of this size, many operating problems are now being experienced which were unforseen at the feasibility stage. One of these problems is the failure of pit slopes and spoil piles at some of the strip mining operations. There have been serious stability problems associated with Utah Development Company's strip mining operations in Central Queensland, in particular the Goonyella Mine. A field investigation programme was under- taken to determine the cause of highwall and spoilpile slope failures. Spoilpile failures were found to result from weakness near the spoil/floor contact zone. Highwall failures were found to result from a combination of unfavourable bedding plane dips and weakness, and the presence of joints in weak o~erburdep; Satisfactory solutions fa the staiity, problems are difficult to formulate, and-field stability experimentation is still at an early Stage.

Jan 1, 1974

Silver and gold bearing ore from the Palmarejo mine, located within the Mexican state of Chihuahua, contains a complex mix of electrum, native silver, silver sulfides and silver chlorides. This paper presents a case study that describes the selection, development and engineering of a tailored process plant for the recovery of silver and gold from this ore. Process circuit feasibility study modelling, metallurgical test work and engineering studies are outlined. Options considered to optimise the recovery of the contained silver and gold are compared, based upon cost, operability, recovery and engineering aspects. Concentration by flotation was found to be the preferred primary recovery route. Intensive leaching of the flotation concentrate resulted in solution grades sufficient to allow direct electrowinning to be evaluated against the more traditional Merrill Crowe process. The flotation tailings stream is processed through a separate leaching stage as there is sufficient economic metal extractable from this stream. The processing flow sheet, which is designed to maximise the recovery from both the flotation concentrate and tailings, and to utilise a common metal production facility, is presented.

Jan 1, 2009

Many mining companies, by their remoteness of location from source of power, have to generate their own power and must experience the same problem that had to be met when deciding to increase the capacity of the power station. At present the Company is treating approximately 54,000 tons of ore mined per month, and the present shift average load. is approximately 8,500 kW. at 0.8 power factor, generated at the power plant, the observed peak load being 10,500 kW.It is proposed to increase the tonnage of ore treated to include 36,000 tons of copper ore, in addition to the present 54,000 tons of lead ore. The average load is estimated to be approximately' 16,000 kW. with a peak load of 17,500 kW. The estimate provides for power of 1,000 kW. to be supplied to the north end leases in the next 12 months, also for increased ventilation in the mines.There are installed in the main power station three turbo alternator sets each of 5,000 kW.; normally two sets are run in parallel and one set is a standby unit. A 12,500 kW. set is being installed and proposed loading with the increased tonnage will require the 12,500 kW. set and one 5,000 kW. set, or alternatively, the three 5,000 kW. sets When the 12,500 kW. set is down for service. When the original plant was installed some 25 years ago, the switches selected and installed in the main 3,300 V. power plant switchboard were rated at 150 MVA and the substation distributing centres located at the surface of the mine, in the mill, and in the smelter, were purchased as having a rupturing capacity of 100 MVA, and the stator...

Jan 1, 1953

The impact of moves to introduce Abori- ginal land rights was felt in the Northern Territory as early as 1972 when the Federal Government froze the processing of all appli- cations for mining interests over vacant Crown land. The Aboriginal Land Rights (Northern Territory) Act was finally proclaimed on Aust- ralia Day 1977 and since that date the mining industry and the Territory legislature have struggled to make the Act work. Despite these efforts long delays have been experienced by those required to negotiate mining and explor- ation agreements under the Act. In fact explor- ation on Aboriginal land has been effectively stiffled since the introduction of the Abori- ginal Land Rights Act. The Northern Territory government and the mining industry have both sought amendment to the Act to remedy some of its more onerous problems. These efforts have generally been fruitless. Some of the recommendations put forward by Mr Justice Toohey following his recent review of the Act would provide relief in some important areas. However, any such improvements are more than offset by a number of Mr Justice Toohey's recommendations which would severely disadvantage the vast majority of Territorians. A recent survey of mining companies seeking exploration licences over Aboriginal land indicates that many of the existing diffi- culties could be overcome without significant amendment to the Act but rather by the adoption of a positive administrative approach by the Land Councils. It is now up to the Commonwealth and the Land Councils to demonstrate that their Act can work without crippling the Northern Territory economy and its mining industry.

Jan 1, 1984

The mineral resource that a mining company has access to, represents the majority of the embedded value that exists within the company, as well as the competitive advantage that the company has over its peers. However, the real value is only realised once effective mining plans have been put in place, which optimise the extraction of the resource, and add measurable value to the company. The concept of mineral resource management (MRM) has been developed in South Africa, to ensure this optimisation happens in an integrated and quantifiable manner, such that value is added and risk is reduced, resulting in bottom line improvement for the stakeholders of the business. This paper describes the process of mineral resource management, and draws on successes and failures of various companies, to illustrate how it should be implemented, and what measures should be put in place to ensure its success. This requires a fundamental re-appraisal of the way in which mining companies plan and execute their businesses, and focuses attention on real value adding activities and behaviour through the use of economic value added as an appropriate metric by which to measure real value and risk. Specifically, the paper focuses on these aspects as applied to planning models and processes, exploration activity and risk management, to ensure operational and project success.

Jan 1, 2006

By Gang L

Seventy-nine gold deposits and prospects have been discoveried in the Jiamusi region of northeast China, and constitute one of the most important gold metallogenic belts in China. All these endogenic gold occurrences can be subdivided into three main deposit types: (1) porphyry related; (2) metamorphic-intrusive hosted, and (3) sediment-hosted deposit. The first two types of gold deposit are spatially and temporally related to Mesozoic Yanshanian granitoid intrusions with hydrothermal activity channelled along crustal-scale fissures. The ultimate cause of the Yanshanian magmatism is considered to be the subduction of Pacific oceanic lithosphere beneath the Eurasian continent. In contrast, The chemical sediment-hosted deposit is typified by the Dongfengshan gold deposit, and genetically related to Proterozoic sedimentation and Mesozoic igneous activities.

Jan 1, 1995

The safety of mine winder systems with regard to overwind, underwind, rope factors of safety, winder brakes and the like is discussed. Many misunderstandings and poten- tially unsafe practices are discussed as well as variations between requirements of various Mines Departments. Various methods to improve safety are suggested and the formation of an industry committee to review present practice and foster development of improved safety and economy is also suggested.

Jan 1, 1984