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Statistical frequency distributions may be used to characterize the overall variation of grade in orebodies. Special types of distribution (e.g. lognormal, log-type A) are necessary to describe skewness inthe case of rare metals. Also needed (but for the most part hitherto neglected) is the serial correlation function which describes the tendency for grades near together in an orebody to be closer together than grades at points relatively far apart.The sampling problem for orebodies is interpreted in statistical terms. Different methods are reviewed, and the effect of serial correlation discussed.A discussion is given, based on experiments and observations made by the author, of biases arising in the minei:l material by such methods as chip sampling and grab sampling due to such causes as nonrepresentative selection by the sampler.INTRODUCTIONMiners have always recognized the large element of chance in their operations. Chance is the raw material of statistical theory and, provided there is some recognizable pattern or underlying regularity in a set of data arising from the operation of chance events, statisticians are able to formulate mathematical models to study them. Mining engineers, geologists, and statisticians have gone a long way between them towards finding general statistical rules which describe the distribution of minerals and metals in orebodies, and even the distribution of orebodies over the earth's surface.These rules do not have the force of physical laws, though they obviously derive from them and have been used to throw light on them. From statistical theory it is possible to find methods of estimating from sampling some of the characteristics of orebodies which are of importance to...

Jan 1, 1962

By Basillo CI

The adsorption mechanisms of various thiol collectors can be subdivided into four classes: chemisorption, EC-mechanism, catalytic oxidation and metathetical substitution. The chemisorption mechanism occurs at potentials below the thermodynamic potentials for the metal-thiol compound formation and is reversible. The EC-mechanism occurs when the mineral is sufficiently oxidised to liberate metal ions to form metal-xanthates; therefore, it is observed with more easily oxidisable minerals and/or with collectors having large pK values. Thionocarbamates adsorb on sulphide minerals via the EC-mechanism due to their large pK values. Although the adsorption occurs at very low potentials as compared to xanthates, it is irreversible with large overpotentials. On the other hand, the adsorption of modified thiophosphates and thiophosphinates occurs near the thermodynamic potentials because of the low pK values. The metathetical substitution is believed to occur only when a mineral is highly oxidised. These classifications are useful for studying the effects of electrochemical potentials and the molecular structure on the collector adsorption Mechanisms.

Jan 1, 1993

By Marshall GA

Structural fatigue damage of haul truck frames is a costly problem associated with the operation of large mine haul trucks. A monitoring programme is described which has been instigated to measure stresses in the frames of haul trucks under actual mine operating conditions. The instrumentation used and methodology employed in the computer analysis of the results is briefly described. The results of the monitoring programmes are reviewed, and the effects of various factors affecting structural fatigue damage of three common types of rear dump truck are considered. Factors discussed include the effects of haul route features (for example shovel, dump and crusher areas); the effect of operations such as turning, braking, loading and dumping; the influence of payload; the effects of malfunctions in suspensions; and the influence of haul route surface quality. It is shown that with respect to payload, while structural fatigue damage is increased with payload, the structural damage per unit of payload does not change significantly for moderate increases in payload above the nominal value. Finally, on the basis of these results, recommendations are made for haul route design and operational practices which will increase the structural fatigue life of haul truck frames.

Jan 1, 1986

The Honourable Neil Pickard has been in Parliament for something like sixteen years. He was Minister for Education in 1976, served as Shadow Minister in a number of portfolio areas while his party was in opposition, and since their return to power in 1988, he has been the Minister for Minerals and Energy. Ladies and gentlemen, I ask you to welcome the Minister, the Honourable Neil Pickard.

Jan 1, 1989

By G Billing a, D Gribble, E Hall, D Varga

The theoretical benefits of electronic detonators have been reasonably well documented. To support this, a practical comparison was made between the performance of the standard shock tube system, NONEL, and a high precision electronic system, HotShotÖ, at the Sunrise Dam Gold Mine. The expected benefits from electronic detonators to Sunrise Dam were identified prior to the trial. Based on these, a number of objectives were set to demonstrate the value of the HotShot system. These are an improvement in fragmentation leading to an increase in productivity, less oversize rehandling, increased throughput and more uniformity in muck pile movement. To maintain the integrity of the trial, the nominal timing of the shots was kept exactly the same, thereby restricting any performance improvements to the precision of the electronics. Accordingly, adjacent shots were chosen with consistent geology. Video footage was taken of the blasts and vibration monitoring was carried out by fixed geophones throughout the mine. Spot heights of the muck pile swell were taken immediately after the blast and heave profile graphs were generated for comparison. Video footage was taken for a period of three hours for both shots to analyse cycle times of the excavator and trucks. PITRAM data was also collected for analysis. As far as practicable, the ore was taken to the same finger on the run-of-mine (ROM) pad to assist in single sourcing for the crusher and to allow oversize to be separated out. From specific metrics taken during the trials, it was shown that the expected improvements due to the high precision timing of electronics were realised in all areas.

Jan 1, 2007

COAL constitutes such a gigantic item in modern industry, either for direct heating, production of coke for smelting, or for the generation of power, that its quality and price play a very significant part in economic industrial progress. Australia is still a very young country industrially, and is groaning under many disabilities compared with competitors overseas, not the least of which is the quality of coal. Linked with the word "quality" should be that of "utility," for high-ash content prevents efficient utilization of the fuel.The marketing of good quality coal is a very important matter indeed, and if industry in Australia is to progress in the way that it should, this matter must receive keen attention.New South Wales, above all the other Australian States, has been blessed by nature with vast coal-fields, from which fuel is shipped to every State, and provides the base for power for most of our railroads and industries.Experts frequently refer to the fact that in some districts only partial extraction of thick seam coal is being made, without a care or thought for the future. Ranking next in importance to this is the fact that much of the coal is being carelessly marketed.Very few collieries in Australia are equipped with coal-washing plants for dealing more particularly with small coal grading which most industries require, and to which coal producers as a whole pay the least attention. In England each year nearly20,000,000 tons of coal is being water-washed before sale, and is marketed as a fuel of far greater utility once it has been freed from extraneous ash.Investigation proves that a great many pits in New South Wales are marketing coal (more particularly small coal) containing a considerable quantity of extraneous ash, due to the admixture...

Jan 1, 1926

An image analysis system has been built which automatically digitizes camera input of rock fragments, analyses the digitised data to determine the sizes and shapes of the rock fragments, and outputs the analysed data to a printer in the form of a histogram or a scatter chart. The high speed of such a system allows for direct collection of data from material thrown into the air by blasting, material travelling on a conveyor belt, and material free-falling on to a stock-pile or into or out of a rock-crusher. Data on the blasted, un-crushed material provides information on changes in the lithology and structure of the rock face as it is quarried or mined: flatter fragments may represent approach to a brittle, unstable shear zone, or a change from sandstone to shale; so that the informa- tion reflects the effect on the sizes and shapes of the fragments by the blasting process and/or by the rock structure. The size and shape distributions of rock fragments produced during blasting and during processing may now be continuously monitored. Such detailed analysis of the results of fragmentation is labour-intensive and expensive when the size and shape distributions are obtained manually, but is cheap and efficient when using this image analysis system. Such a system will enable the results of blasting, quarrying, mining and crushing to be cheaply analysed and correlated with current and changing indus- trial practice so leading the way to increased productivity.

Jan 1, 1988

From 1980 to February 1991 the Rosebery concentrator purchased ore from Aberfoyle's Que River Mine. Following the termination of the contract the concentrator reverted to treating Rosebery ore alone. Since that time it has become apparent that the circuit configuration employed was no longer optimum for zinc metallurgy. The circuit was designed to treat a difficult, slow floating sphalerite; however, the opposite was now found to be true. The sphalerite is fast floating and the circuit was cumbersome. During 1992 extensive circuit changes led to the provision of a simple open circuit flow sheet. The circuit is now easier for operators to understand and lends itself to improvements in process control. Middlings streams have been minimised, which produces a far more stable circuit. Significantly, it must be noted that the key to achieving potential results must lie in reducing variations within the process. A significant ore characterisation program has been undertaken, providing an insight into the metallurgical compatability of the ore to be mined. Using the information collected in this program, metallurgical recoveries and grades can now be predicted with a geater accuracy. Ore characterisation data suggests that an improvement from a 54 per cent zinc concentrate to a 57 per cent zinc concentrate should be achievable. By understanding the size-by-size mineral assemblage, a strategy for concentrate grade improvement has been developed. The requirements of the customer must in all cases determine the quality of the product. Pasminco is a fully-integrated zinc producer and as such significant gains can result by tailoring the concentrates to suit the Smelters.

Jan 1, 1993

By H R. Phillips

The ventilation and refrigeration design of underground mines is an important aspect, when new or existing mines are considered and places a great responsibility on engineers tasked to do so. The current trend for both local and international underground mines is to extend their search for valuable ore reserves deeper below surface. In South Africa, the predictions are that about 40 kt of actual gold still lies in situ, ready for extraction. As mines extend their search for minerals of economic value deeper and deeper into the earthÆs crust, ventilation and refrigeration aspects of such mines become more prominent than before. The planning and design of the required ventilation and refrigeration within these mines, over their expected lifetime is important including the practical implications of such designs. Technology changes and improvements need to be incorporated into ventilation and refrigeration designs, where possible and advances in this specialised field explored. This paper explores ventilation and refrigeration design aspects within the underground mine sphere. Aspects such as mining depth, virgin rock temperature (VRT), mining methods, and different cooling applications available including ventilation supply are reviewed in design applications. Heat generally becomes a significant aspect to counter in these mines and they are not always necessarily deep mines.

Jan 1, 2005

By Parker RJ, Swindells CF

The authors have used the geotechnical study for design of the South Wall of Mt. Newman Mining's Mt. Whaleback Mine to illustrate how geotechnical studies can be economically justified. This is achieved by relating the savings resulting from increased ore recovery and prevention of failure to the cost of the study. An outline of the geotechnical study is provided in the paper, including a brief description of the innovative methods used to investigate geological structure of the mine and descriptions of the methods of slope reinforcement adopted.

Jan 1, 1986

By Gilligan P

The Selwyn gold-copper operation is wholly owned and operated by the Arimco mining group. The mine is located 150 kilometres south-east of Mount Isa. The primary extraction method for the gold-copper 251 orebody is by sub level open stoping. Secondary extraction is from the mass blasting of the remaining crown and rib pillars. The final mass blast of the 251 orebody occurred in December 1993. This paper details the design and execution of that firing.

Jan 1, 1994

By D Morris

This presentation discusses a water filtration technology termed Fabric Media that is somewhat novel to the Australian market place and reports several recent mining industry installations. Like many novel household cleaning products, the Fabric Media technology applies the science of active washable micro fibres as the means of capturing contaminant solid particles. The simple Fabric Media water filtration product offers several attractive attributes when compared to the more traditional media bed filtration processes such as sand filters, and barrier filters such as micro membranes. A micro fibre based filtration media enables both superior adsorption for the contaminant and wash ability. Stronger adsorption capture enables a much higher flux and greater solids loading density for the filtration task, meaning that lower cost and smaller footprint equipment is available. For Fabric Media water filters, a textile weave is selected that minimises the flow backpressure for a given particle size separation. Thus for an equivalent filtration performance this provides a much lower operating energy requirement, generally between 50 and 80 per cent less than for a sand filter. A Fabric Media is not abrasive to itself or to the filter tank. The filtration performance remains constant and predictable. The equipment life is much longer and the asset value of the new filtration equipment should maintain throughout the project life. Fibres are extremely mechanically robust and chemically inert. Fabric Media survives repetitive exposure to a rapid mechanical washing event providing high wash efficiency with minimum equipment off-line time for the backwash. Dislodging captured contaminants by a high-speed mechanical agitation enables a minimum off-line time during backwash events. The vigorous backwash destroys adhering flocculant and eliminates the formation of mud balls, which can permanently foul sand filters. The mechanical agitation wash of the Fabric Media water filter ensures complete removal of grease and biofilm, which can adhere and block a membrane surface. In comparison to sand filters and micro filtration membranes, the Fabric Media product is applicable to a significantly wider range of solids concentrations without permanent damage. The technology is very forgiving to excursion in plant control and is therefore considered a very operator-friendly concept.

Jan 1, 2006

An Investigation on the Effect of Chrysotile Particle Shape and Anisotropic Properites on the Rheology of Chrysotile Suspensions Chrysotile, a polymorph of serpentine, is a phyllosilicate mineral that occurs as a major gangue mineral in many ores (eg Mt Keith nickel sulfide ore, Western Australia). The rheological behaviour of chrysotile stems from two main factors: its distinctive morphology and its electrical surface charge. It is believed that these factors are central to the problematic rheological behaviour and low solids throughput typically experienced in the processing of such ores. In this work, a study of the effects of chrysotile surface charge properties and particle shape on the rheology of chrysotile suspensions was conducted. It was found that the rheology of suspensions of pure chrysotile is characterised by extremely high yield stress values over a broad pH range (pH 4 to 11).The disparity in the point of zero charge and range of maximum yield stress for chrysotile is consistent with the anisotropic nature of chrysotile particles. A comparison of the rheological behaviour of quartz suspensions (non-fibrous) to that of chrysotile suspensions (fibrous) provides a practical indication of the effects of the fibrous nature of chrysotile relative to non-fibrous minerals. The long, thin fibres are easily entangled to form suspensions with much higher plastic viscosities and Bingham yield stresses than non-fibrous particles. Chrysotile particle shape and surface charge are central to the rheology of chrysotile suspensions, although shape appears to play a more significant role in this regard. This fundamental study would be beneficial to the ongoing research for improved recovery in the Mt Keith nickel sulfide ore as well as other chrysotile bearing ores.

Sep 13, 2010

By Smit J. G

Following an increase in the number of methane ignitions in South African coal mines a new ventilation system was developed. The "Hydravert" system conceived in late 1979 for use in low seam coal mines, where the bord and pillar method of working is used, has been extensively developed to include applications for mining seams up to 4.5 metres high. A brief history of the development is supplied including some of the pitfalls encountered in the hydraulic equipment design and selection.

Jan 1, 1988

By G P. J Dijkema, M A. Reuter

From a material cycles perspective all processes are interconnected and consequently a process can never be evaluated as an isolated and independent unit. This also holds true for the evaluated co-incineration options. Environmental and sustainability issues for example, such as raw material and energy utilisation or air pollution, are a resultant of the whole system of industrial activities. It is therefore important, not to optimise a single process or industrial activity, but rather the whole system. Although engineering procedures for the design of individual industrial units are well developed, the problem of determining the best arrangement of these interconnected units is often far more difficult. Regulation that manages the arrangement of the units for waste processing is still under construction. In the evaluation of co-incineration, analogous principle from process control can be used: feedforward control. This principle includes the determination of which outlets can be used for all process outputs, hence avoidance of any æunusableÆ products or wastes possibly arising from co-incineration. To establish the extent, to which produced wastes are usable, a system overview is necessary, in addition to in-depth information on the subsystems, which produce and can consume wastes. Material cycles modelling can be used as the basis for a tool that supports the development of a suitable playing field. It should provide overview of the system and in-depth information on its subsystems. This tool then represents an attempt to bridge the gap between æholisticÆ industrial ecology and process engineering.

Jan 1, 2000

'Nothing happens until something is sold' This statement is not original - it is a necessary orientation for marketing industrial minerals. The most important single philosophy of marketing is that it recognises the consumer as the starting point. Production orientation is concerned with producing products that the customer might buy. Market orientation is concerned with finding the needs of the customer and how they can be satisfied. The difference between the two approaches can be recognised in company structures but the most tangible difference is in the approach by a company to selling and development. In other words, it is the market that decides what can be done with a mineral. The markets requirements dictate what mineral, what grade and what price will be paid. Therefore it follows that when pricing a product we should avoid taking the basic cost and arriving at a final selling price through a series of standard markups (unless government insists on it). We should start with the price the market can stand and work backwards to find out whether you have a profitable product or one that will fail because it is too dear. Naturally a thorough understanding of production costs is necessary particularly when marginal markets are concerned.

Jan 1, 1978

Mining companies around the world devote considerable effort to production reconciliation and metallurgical accounting. However, although sampling, weighing and analysis methods used to obtain the raw data for metal balancing continue to improve, they are still areas that are sadly neglected. Using the latest metallurgical accounting package to improve metal balancing is fundamentally flawed if the data used are unreliable in the first place. The basic rule for correct sampling is that all parts of the material being sampled must have an equal probability of being collected and becoming part of the final sample for analysis. If this rule is not respected, sampling bias can easily be introduced. Unlike precision, which can be improved by replication, bias cannot be reduced once it is present. Sampling and sample processing procedures must therefore be carefully designed both to minimise bias and to obtain acceptable precision. The most suitable sampling location is the discharge point of a process stream, where increments can be obtained by taking a complete cross-section of the stream with a sample cutter. Sampling devices that take only part of the stream may introduce serious bias and must be avoided. The moisture content and wet mass of the material being sampled are of similar importance to chemical analyses for determining metal content. The accurate determination of moisture content is particularly difficult, because the moisture content of samples can change after the sample is taken, eg due to moisture evaporation. Hence, moisture samples need to be taken quickly and placed in sealed bags or containers that are impervious to moisture. The moisture content should then be determined without delay. To determine wet mass, a range of weighing methods are used in industry, including weighbins, weighbridges, conveyor weightometers and platform scales. The precision and accuracy of these methods vary considerably, so it is important to select a method with the appropriate precision and ensure that the weighscale is well maintained and regularly calibrated.

Jan 1, 2002

By A Seneviratne, Y Li, N Udugampola, X Ai, B Li

LoRa (Long Range) is a low-power, long-range wireless communication technology that has gained significant research interest for its potential use in multi-hop linear wireless sensor networks (LWSNs) for underground mines. These networks deploy LoRa-enabled sensor nodes in underground mines, together with LoRa repeaters placed along mine tunnels to relay sensor data to a LoRa gateway, which connects to a backend network for application-level processing. Since the packets generated by sensor nodes farthest from the gateway have to hop through many repeaters, their probability of successfully reaching the gateway is significantly lower due to the higher chance of packet collisions compared to sensor nodes closer to the gateway, resulting in a lack of network fairness for the sensor nodes. In this paper, we first present an algorithm to improve the fairness of a LoRa LWSN by grouping neighbouring nodes and adjusting the number of packet re-transmissions and transmission intervals for each group. Then, we demonstrate that the fairness of a simulated LoRa LWSN can be improved by approximately 500 per cent by applying our algorithm. We verify our algorithm with network simulations under different network traffic levels and grouping strategies, obtaining fairness improvements in each scenario. Our algorithm and results will pave the way towards developing highly fair LWSNs for underground mining applications.

Sep 1, 2024

The comparatively low winter rainfall, exposure to heavy salt laden coastal winds, and the consequent high evaporation rate, are important considerations in the rehabilitation of the Maslins Beach Sand Pit. The deficit of rainfall over evaporation is assessed at 1085 mm per annum. Such a coastal environment complicates the establishment of plants. The endemic flora found on the Sand Pit environs is mainly low wind-planed shrubs and mat plants. The dunes near the coast support an association dominated by Atriplex cinerea, Spinifex hirsutus, Scirpus nodosus, and Olearia axillaris. The coastal cliffs carry a more diverse vegetation dominated by Beyeria lechenaultii and Eutaxia microphylla. Overburden is used to develop a new landscape to screen operations, batter final faces, and cover rubbish at the nearby Council dump. The early overburden dumps were built with little regard for stability, but the more recent practice of using scrapers has resulted in more stable dumps. The erosion problems created by poor compaction have been controlled by contour banks, diversion drains, bitumen lined run-off drains, and hay mulching.

Jan 1, 1976

Agglomeration Drum Selection and Design A model has been developed by for drum agglomeration which allows selection of geometry and power input. Specific aspects considered are: calculation of total operating volume, solids residence time based on drum geometry and operating parameters, selection of the drum aspect ratio, selection of proportion of critical speed, calculation of rotating power requirements. The model uses solids total residence time to calculate the required operating volume. The burden density is calculated from the solids bulk density, agglomerate packing and the fluid density. Power is calculated using a modified Liddell and Moys correlation for burden position and shape, and the operating drum speed. A further power allowance is made to allow for accretion drop off during drum rotation. Results from the model (especially power and per cent operating fill) have been verified from industrial installations of significant size. Predicted and observed power draws are within five per cent when burden slip and bypassing are not significant. When these are significant (at fills above 15 per cent) the actual power draw will be less than the model prediction. Under these circumstances the quality of the agglomerates will be poor.

Sep 13, 2010