Search Documents

This paper presents a review of heat illness in mining, including reference to several recent investigations by the author. Heat illness is a collective term, covering the conditions of heat stroke, heat exhaustion, heat cramps and miliaria rubra. Heat stroke is life-threatening and is by far the most serious condition. It is rare in mining, if appropriate control measures are instituted. Heat exhaustion is primarily due to hypohydration, following prolonged sweating in hot conditions. Symptoms include fatigue, headaches, dizziness, anorexia, nausea, vomiting, shortness of breath, or brief syncope. Confusion, ataxia, prolonged unconsciousness or convulsions are strongly suggestive of heat stroke. Heat cramps are painful involuntary contractions of skeletal muscle associated with work in hot conditions. The limbs are usually involved and the spasms typically last a few minutes, during which the affected part of the body is incapacitated. Heat cramps tend to occur in heat exhaustion, when hypohydration becomes marked. Miliaria rubra is a skin rash caused by extravasation of sweat into the skin, as a result of obstruction of the sweat glands. It occurs after prolonged and profuse sweating in hot environments. It can take three to four weeks of sedentary duties, in an air-conditioned surface environment, for the condition to resolve. Heat illness would be unlikely in underground mining, if the thermal environment was sufficiently well controlled by ventilation and refrigeration. This is however, often not practicable. Where engineering controls alone cannot provide sufficient control of risk, the residual risk can be assessed using an appropriate heat stress index. While procedural controls may further reduce the residual risk, it is important to remember that these are less reliable than engineering controls and cases of heat illness may still occur. Procedural controls include the application of heat stress limits, education, hydration, self-pacing, early symptom reporting, medical advice, acclimatisation procedures, air conditioned accommodation, support to achieve a healthy body mass index, and an effective emergency response capacity.

Jan 1, 2005

Groundwater issues for the mining industry are many and varied. When the depth of mining is below the water table/potentiometric surface, a groundwater æsinkÆ is created which alters the local groundwater flow regime resulting in minewater inflows. Assessment of mine dewatering, mine water balance and wastewater disposal requirements are central to the effective management of water in a mining operation. Each of these issues has a significant groundwater component. Other groundwater issues for mining operations include: water supply, aquifer storage and recovery, the impact on other groundwater users in respect of groundwater levels, bore yields and water quality, and the development of an effective groundwater monitoring network for early detection of impacts and to satisfy regulatory requirements. This paper outlines the techniques involved in assessing groundwater issues for project feasibility, during operation and post closure, and provides an overview of several mine dewatering and water disposal methods. The practical assessment of groundwater issues for the mining industry is illustrated with several case studies of mining projects in Australia, SE Asia and the subcontinent. These are projects to which the author has contributed during a career as a geologist/hydrogeologist spanning more than 25 years.

Jan 1, 2003

The risks faced by organisations are part of a risk continuum. They can be evaluated in terms of hazard, uncertainty and opportunity as well as by the degree of influence they have on conformance, operating performance and strategic objectives. This paper discusses the application of risk management techniques for mitigating blasting hazards, reducing blasting output variability, and implementing blast improvement opportunities. Effective risk management practices can identify and evaluate risks across all levels of the continuum and can deliver realistic assessments of the likelihood and impact of risks on the companyÆs safety and business objectives. This paper does not attempt to present technical details about blasting, rather it aims to provide enough blasting context and examples so that the practical benefits of applying the risk management process to blasting can be fully appreciated. The topics discussed include: explosive management plan; statistical process control; quality blasting, rock-on-ground; Blast Management; Mine to Mill optimisation; and blasting information systems. The concept of a blasting risk management system employing a continuous improvement loop is also introduced. On reflection the insights presented should be extremely useful for observing and understanding which risk face has management focus at a mine site or for a blast site.

Jan 1, 2001

This paper examines the broader implications of recent and ongoing changes in mineral resource managementå and reporting practices and the impact that these might have on mining companies. It is likely that an International Reporting Code will be developed in the near future, based on a number of National codes produced in recent years. However, this is only part of the reporting story, as an International Code brings with it a range of further issues to resolve. For the Code to be effective, there needs to be international recognition and perhaps licensing of Competent Persons and an expanded base of sponsoring professional bodies. Also, in an increasingly global business, shareholders, regulators and other interested parties need to know and understand the general processes involved in resource and reserve estimation and reporting in order to recognise companies that maintain the highest standards. There is a current trend towards greater scrutiny of company performance in a range of areas under the banner of corporate governance, and many changes are happening that will place greater disclosure burdens on all companies in the future. Good corporate governance means management of company assets for the benefit of the stakeholders. For a mining company, there is no greater asset than its mineral resources and reserves and directors are just as responsible for effective management of their mineral resources as they are for financial good practice. The paper looks at the relevance of corporate governance principles to mineral resource management and the changes that this could bring to the way that companies deal with regulators, shareholders, financiers and others. Finally, increased scrutiny and further regulation inevitably means greater effort by the industry and higher costs. Despite this the author believes that there are substantial offsetting benefits to be gained by companies prepared to take the initiative in improving resource management practices and communicating these improvements to shareholders. In order to achieve the benefits however, the industry needs to fully engage in the changes that are taking place û setting its own standards and working with the regulators rather than sitting back and being legislated against. Mineral resource reporting provides a good model of how this process can work and there will be other opportunities in the coming years as the industry seeks to develop best practice in mineral resource management. The author is an employee of Rio Tinto but wishes to point out that the views expressed in this paper are his own and not necessarily those of Rio Tinto.

Jan 1, 2002

By A Grice

AMC has completed a number of backfill options studies, including several in recent years for large, three-dimensional orebodies involving total extraction by longhole open stoping with backfill. This has led to the development of a thorough review methodology that assists in the selection of the most appropriate backfill system and the most economic mixes to achieve the required performance. A recently developed design tool has simplified the calculation of backfill strengths for various exposure dimensions and automatically determines strengths incrementally over the height of a stope. Using a generic orebody with a plan dimension of 120 m wide by 360 m long, several different stoping layouts have been analysed to determine the effect of stope dimensions and sequencing on backfill strength requirements. This has been done for stope heights from 50 m to 300 m, in 50 m increments. The required strengths have been calculated in slices and summarised for each stope in four equal layers. The average strength requirement for each layout at each stope height has been compared graphically. For all stope heights, a panel stope layout that minimises the proportion of primary stopes results in a lower average strength requirement than grid layouts on a checkerboard pattern. However, for very high stopes, smaller plan dimensions become more economic. The increase in required strength with stope height is non-linear, making taller stopes potentially more attractive. The main cost factor in most backfills is the rate of binder addition, which is closely related to the strength required. By choosing a layout that minimises the backfill strength requirement, significant savings in binder addition rates and overall costs can be achieved. These must, of course, be weighed against other factors to determine the optimum stoping layout and backfill system.

Jan 1, 2000

Offshore petroleum development involves massive capital expenditure and financing demands, with the main participants being large international oil companies and State owned enterprises. Types of project oriented financing include take-or-pay contracts, throughput agreements, and production payment financing. The main project finance credit aspects are revenues, investment budgets and cost over- runs, reservoir, political and other risks and special problems such as weather and corrosion in the North Sea. A variety of documents is required and a mix of equity, export credit and Euro-market financing will typically be included in the financing.

Jan 1, 1983

By Satayev IS, Shepelev DV

Various ways for applying the X-ray fluorescent method to process lump-by lump separation of secondary aluminium raw materials (scrap, slags, waste) as well as ferrosilicon and ferrochromium are being considered and physically demonstrated. A commercial X-ray radiometric sorter has been developed for processing secondary raw materials. Marketable quantities of aluminium scrap with appropriate copper and zinc content have been produced for smelting with a minimal additional of pure aluminium. An industrial complex for scrap processing, incorporating two X-ray radiometric sorters from the Hammermils company is successfully operating at one of the works in Russia.

Jan 1, 1993

Gold bearing sediments at Scotland Point occur within the Quaternary Gibbston Fonnation, which underlies Cromwell Flat in Central Otago. Gibbston Fonnation unconformably overlies Teniary Manuherikia Group clays, sands and quartzose gravels. Gibbston Formation sediments are composed of a texturally diverse, multistoried lithostratigraphic succession of sandy/gravelly/bouldery lithofacies, deposited within a multiple channel (braided) depositional environment. Lithostatigraphic analysis indicate an upward overall decrease in average grain size, reflecting a concomitant reduction in stream competence. This trend results from progressive channel abandonment as major distributaries avulse across the outwash plain. Grade distribution of alluvial gold is controlled by aggradational and to a lesser extent degradational lithofacies deposited as distinctive braid bar forms near the base of the sequence. These lithofacies were deposited at different topographical levels on the outwash apron, under variable hydraulic conditions. Recognition of large-scale auriferous bedforms within the braid bar depositional system coupled with an understanding of lateral facies relationships, allows headgrade control on run of mine ore and quick determination of overburden to ore ratios.

Jan 1, 1988

Activity-composition-temperature relations for both gold and nickel have been determined for the solid and liquid states of the gold-nickel system by the application of the Margules equations. These relations are in satisfactory agreement with activity measurements of nickel in the solid state, the observed phase boundaries of the system between 700 and 1725°K, as well as being consistent with data on the enthalpy of mixing.

Jan 1, 1971

By Rolley P

In the course of reviewing grade control practices at the Marvel Loch gold mine in Western Australia in 1992, FSSI Consultants developed and implemented a novel approach to ore selection using a method to maximise financial return (the MP method*). The approach was based on improved grade control sampling and an ore selection method which directly incorporates both a measure of the uncertainty in knowing the true grade of selection units in the definition of ore, as well as the operating cost and revenue parameters of the mining operation. During the past four years, FSSI Consultants have evaluated and refined the use of this approach and have implemented customised variations of the MP method at seven gold mines and a gold-copper mine in Australia. The previous methods of ore selection at most of these operations were based mainly on polygonal - sectional methods of grade estimation. At all of the sites where grade control optimisation has been given a fair trial over several months of production, the use of the MP method has been consistently rewarding to the mining operations. The benefits include increased run of mine ore stockpiles and low-grade stockpiles and decreased fluctuation in the production grade. Most operations have also benefited from a consistent ability to improve production grade through high-grading of the increased ore production. The increase in ore production has the logical benefit of reducing stripping ratios, increasing mine profitability and mine life.

Jan 1, 1997

Author Biography William Poole was born in Sydney, NSW in August 1868. He was educated at Sydney Grammar School. William spent two and a half years as a cadet in the Railway Construction Branch of the NSW Department of Public Works doing office and field work. He then undertook a civil engineering course at Sydney University. Following this he was employed for six years as assistant and resident engineer at the Water Conservation Branch, NSW and was in responsible charge of various field operations, surveys, river gaugings and works of constructions including a large timber weir and also a concrete weir on the Macquarie River, NSW. He then undertook a mining and metallurgical course at Sydney University and became a graduate (BE) with honours in civil engineering, mining engineering and metallurgy. He then spent four and a half years with BHP Co, one and a half years at Broken Hill in the mining and concentration works and three years at the smelting works in Port Pirie, SA, in the latter case he was metallurgist and night superintendent and during that time had responsibility and control at night of the blast furnaces and, during the last 15 months, of the whole of these large works. The author left the Port Pirie, SA works to assume the position of Director of the State School of Mines at Charters Towers and had responsible control of the establishment and also lectured in mining, surveying and structure. William Poole was honoured to hold membership in the following organisations: Assoc M Inst C E, L S of NSW, M Aus Inst M M, Assoc Inst M & M (London).

Jan 1, 2006

A key premise to this paper is that most people involved in the design and implementation of drilling and blasting operations could benefit from a greater understanding of the geological materials, deposits and landforms they are dealing with. The second key ingredient for successful blasting is the concept of blasting objective. Mine operators and blasting contractors must be clear on what drives their costs (blasting leverage) and should formulate blasting objectives and operational targets which help in this regard. Many operators ignore geology descriptors and features apart from the name of the rock and start crudely quantifying the rock mass properties in terms of uniaxial compressive strength, or even worse still as hard or soft. This occurs too early in the design process and not much attention is paid to the geological materials, geological structures and the characteristics of the deposit they intend to excavate. In effect the rock type name and the strength descriptor become the site geology. Furthermore many blasting operators do not formalise their blasting objective, do not set operational targets and do not measure results to the degree required for continuous improvement. In this paper a number of civil, surface mine and underground mine blasting applications are tabulated in terms of typical blasting objectives and common geological materials. A good description of geological materials can convey a lot of useful information for blasting operators if they are able to accommodate this knowledge. In addition a clear statement of the blasting objective and associated operational targets will maximise the likelihood of achieving blast-driven downstream productivity improvements. The æStarting at Both EndsÆ combination is deemed extremely useful for any continuous improvement blasting program.

Jan 1, 1999

Erratic, though spatially localised occurrences of gold particles are a common feature of high-nugget gold systems. In many cases, gold is present as isolated or clustered, often coarse particles. The nugget effect is a part consequence of small-scale geologically controlled enrichment, and the inclusion or exclusion of gold particles from samples. Economic zones are generally contained within discrete structurally-controlled ore shoots which are surrounded by, and may include barren to low-grade background material. Problems are often encountered where small sample types (eg drill core and channel samples) of a few kilograms mass understate in situ grade by up to a few orders of magnitude, due to their general inability to represent the true gold particle distribution. This leads to uncertainty in mineral resource estimates. This contribution presents case studies where geologically-based parameters have been collected from drill core and underground faces to support grade determination. These parameters - or proxies - are based on mineralogical and/or geochemical (eg specific elemental ratios, fluid inclusion compositions and elemental correlations) criteria. Such criteria can be correlated with different grade domains to provide an indication of true grade within a geologically-controlled context. Proxies have recently been used to support resource estimates reported in accordance with the JORC Code.

Mar 1, 2010

IT is generally accepted that for transport of coal underground from different collecting stations, the system of endless rope haulage with remote control is not only one of the safest and most economIcal, but is also one of the most'efficlent in dealing with output.When the coal measures lie in regular planes, the work of laying down such a haulage presents no difficulties. When, however, the dip of the measures is Irregular, or dislocated by faulting, the management is faced with the problem of constructing vertical curves of such a radius that the sag of the rope will correspond with the road bed, and thus obviate the danger of the rope rising and throwing the skips off the track.The direction of the main roads for haulage purposes being ascertained from the plan of the royalty to be worked, the faults or dislocations in the seam are determined for these roads with the greatest possible accuracy by means of bore holes from the surface.From the data thus obtained the haulage road can generally be so graded that the rope will keep on the floor during haulage operations, although the grades may in places be synclinal.The writer confesses that he knows of no accurate formula for calculating the sag of the rope under varying tensions and so determining the safe radius of the curve, and he had to depend upon past experiences under somewhat sImilar conditions.The accompanying sections illustrate a case where the writer has recently installed an endless rope underground approximately 5000 ft. in length, from the foot of a tunnel in which an endless rope delivers the output to the screening plant, and having to negotiate, first a 400-ft. downthrow fault, and later a 32 ft. upthrow.

Jan 1, 1927

Prior to 1972, Peko Mines Limited at Tennant Creek used a central mill at Peko, which consisted of a gravity circuit, flotation and cyanidation of tailings, to treat their gold ore from surrounding mines. The Warrego concentrator, 60km to the west, was built to handle the Warrego and Gecko copper orebodies, which were being developed concurrently with the concentrator construction The Warrego concentrator consisted of a flotation circuit, using autogenous grinding at 100 - 120 tph, compared to the more elaborate Peko circuit employing rod mill - ball mill grinding capable of treating only 18 - 26 tph. During development of the Warrego copper mine a gold rich ore pod was located, because of which the mining plans were adjusted to allow simultaneous, separate extraction of the copper and gold ores. However, the plans for the concentrator were not affected as the gold ore could be carted 60km to the Peko central mill for processing.

Jan 1, 1978

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

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988

Arm Royalty systems of different types are used throughout Australia by both state and federal governments to raise revenue and thus facilitate in the proper distribution of mineral wealth. Royalty systems should be neutral and equitable but by their very nature these objectives are impossible to obtain. Because of the individual nature of mineral deposits, in particular variable cutoff grades and tonnages, governments should be aware of the possible trade off between short and long term gains of the particular royalty scheme introduced.

Jan 1, 1982

By Warner B. D

Smelting at Mount Morgan started in 1906 with blast furnaces which were replaced by a reverberatory furnace in 1939. The second reverberatory, commissioned in 1944, was replaced by a copper flash smelter in 1972. Flotation concentrates, dried to 0.05 per cent moisture, were oxidised under accurately controlled conditions and produced 45 per cent Cu matte and a slag in the flash smelter. The matte was converted to blister copper and the slag was slowly cooled before grinding and retreatment in a flotation concentrator.

Jan 1, 1974

By Meakins R. L, Talaska A, Kenny D, Haycraft J. A, Dickson B. L

A vehicle-mounted radiation detector interfaced to a microprocessor called PRAM (programmable radioactive analyser mobile) has been developed to provide grade control for selective mining of a soft rock uranium ore. The grade of ore over which the vehicle passes is determined and indicated by several coloured lights to a pegman who walks behind the vehicle. Coloured pegs are then laid out to mark the uranium grade ranges on the floor of the mine pit. Comparison between grade ranges determined by the PRAM and by prior drilling and downhole logging at the Yeelirrie deposit, Western Australia indicate good agreement. Use of the PRAM decreases the cost, manpower and time required to grade extensive areas of a mine pit floor.

Jan 1, 1982