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By Johnson G. D

The typical management systems used to address the issue of operating risk centre around technologies that identify, analyse and evaluate the risk factors. These logical systems such as HAZOPs, Fault Tree Analyses, etc rely heavily on technical considerations and process flow analysis. However, several research projects, across industries and countries have clearly shown that up to 80 per cent `operating risk' is determined by the actions of workers, supervisors and managers. Yet, most of the focus of risk management is on technical and procedural issues. This suggests that a significant imbalance exists in our management systems and that industries are unlikely to show significant improvement on current levels of safety performance. Effective risk management must include the intangible element of the organisation psychology towards risk. A practical and theoretically sound approach had been researched and developed in and for the mining industry. This paper describes the approach and methodologies applied at the Cosmo Howley Gold Mine in the Northern Territory, where an inclusive approach to managing financial and operating risk was followed. The Cosmo Howley Mine showed a dramatic reduction in lost time injuries and improvements in financial indices - providing conclusive evidence of the link between management effectiveness, safety and productivity. This `triangle' has often been the subject of speculation and theory. It is demonstrated in this paper how the management team of Cosmo Howley focused their practices and systems on the improvement of organisational dynamics, ensured tangible and clear focus on parameters of costs and safety and how the improvement process was managed. It is concluded that the improvement process did not require a `major re-engineering' of the organisation. The organisation culture changes that occurred were incremental, planned and effective. It entailed the implementation of sound risk management methodologies, and ensured that a significant emphasis was placed on an aspect that is defined as `organisational dynamics'.

Jan 1, 1994

Mineral resource and ore reserve classification defines the risk associated with quoted resource tonnes and grades, allowing the interested party to make a judgement as to the `worth' of the resource statement. The JORC Code and Guidelines (1992) are now well entrenched as the foundation upon which gold and base metal deposits in particular are publicly reported. There are three categories of resource, namely Measured, Indicated or Inferred reflecting decreasing levels of confidence. The ore reserve, that is the economically mineable part of the resource, is classified as Proven or Probable and can only be drawn from the Measured and Indicated resource categories. As summarised by Stephenson (1995), resource/reserve classification has been an issue ever since the earliest days of mining in Australasia where, like elsewhere in the world, the industry, for a long time, lacked firm reporting guidelines. Those currently adopted in Australasia as the minimum standards for companies reporting to the Australian Stock Exchange (ASX) have been developed and revised since 1972 by The Australasian Institute of Mining and Metallurgy (The AusIMM), the Australian Institute of Geoscientists (AIG) and Australian Mining Industry Council (AMIC). Debate is now underway in terms of adopting an international code. The Code specifically does not attempt to regulate either the classification technique nor the method of estimation of the resource/ore reserve, but rather places the responsibility for this task on a `Competent Person' whose experience will decide the appropriate approach for a given commodity/orebody. The Competent Person must be a Corporate member of either The AusIMM or AIG with five years experience `relevant to the style of mineralisation' under consideration.

Jan 1, 1996

By Rosengren KJ

Geotechnical conditions often have a critical influence on the design of new open pit and underground mines, but they are often considered of secondary importance in relation to other factors, such as detailed geology, orebody geometry and grade distribution. As a result, geotechnical studies may not be carried out during early project investigations or, at best, may be given only superficial attention, often to the overall detriment of the project. Technically and economically, it is logical that geotechnical studies should be integrated with geological investigations as soon as it becomes evident that the particular deposit may prove to be economic. The paper discusses the use of geotechnical information in the selection of mining methods and mine design for underground mines and for wall design and assessment of excavation characteristics in open pit mines. It then considers methods of obtaining the relevant data, with particular reference to exploration boreholes. Selected case studies on the application of geotechnical data to mine design are Included.

Jan 1, 1986

By McGill RA

The Ranger Uranium Mine is surrounded by a World Heritage National Park. The strict environmental controls under which the mine operates are based on scientific and social requirements. Release of non-process storm runoff water to the Magela Creek during flood discharge and under controlled conditions has been identified as Best Practicable Technology for the operation of the water management system. Social and political factors have limited this release to a wet season with an Annual Exceedance Probability of one in ten. The first-generation trigger mechanism was based on a percentile analysis of monthly rainfall. The second-generation trigger is based on cumulative monthly volume increase in the retention ponds and is considered to be more applicable to the operation of the mine water management system.

Jan 1, 1988

In response to requests from the iron ore mining industry, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Division of Mineral Physics has developed a number of bulk analysis techniques in which analyses are obtained directly from ore samples weighing many kilograms or from ore located on conveyor belts.Because penetrating neutron and gamma radiation is used, measurements are obtained from a large volume of ore, which ensures thal the analyses are represelllative of the bulk.Two different gamma-ray techniques have been developed to measure iron ore grade. The first is based on backscallering of 60CO gamma rays, while the second involves measurement of the annihilation radiation which arises when the ore is irradiated wilh 226Ra gamma rays. Both techniques measure the iron concentration with an accuracy (1 s) of better than 0.4% Fe.A thermal-neutron irradiation technique using a 252Cf neutron source has been developed for the simultaneous determination of iron and the aluminium impurity (expressed as AI2O3) in iron ore fines on a conveyor bell. Because the conveyor speed must not exceed about 0.05 m/s, if good accuracy for AI2O3 is required, an auxiliary analysis bell is required Lo avoid inLerference with normal ore processing. Dynamic trials have demonstrated that accuracies of 0.6% Fe and 0.1% AI2O3 can be obtained.

Jan 1, 1985

By A B. Richards

Effective control of blast vibration and flyrock requires that significant factors be identified and quantified, that the blast be designed to ensure both blasting efficiency and compliance with applicable limits, and that the blast design be effectively implemented by field personnel. Significant factors contributing to ground vibration and airblast are: charge mass; distance and direction relative to the blast; drilling design: burden, spacing; stemming height and material type; hole diameter and depth; and initiation sequence and direction.In addition, airblast may be strongly influenced by shielding and meteorological conditions. Ground vibration is also influenced by the transmission characteristics of the ground and soil. Flyrock throw is determined by charge mass, burden, stemming height, blasthole diameter and depth. The contribution of each of the factors has been quantified and models developed to enable the environmental outcomes of blast design to be predicted. Environmental blast design is necessary to ensure compliance with regulatory limits and the implementation of æsafeÆ exclusion zones for flyrock clearance. This paper discusses the models used for environmental blast design and demonstrates the often significant effects that lapse during implementation of the design can have on predicted outcomes. In practice, drillers and shotfirers are sometimes confronted with situations that require modifications to the blast design to cope with the real site situation. Methods are presented that may be used by drillers and shotfirers to evaluate the effect of these modifications, the tolerances that must be reached during their work practice and checking procedures, and the consequences of their actions.

Jan 1, 2004

By F J. van Zyl, C A. S Thomson

"Anglo American Thermal Coal conducted a high level study of all of its underground collieriesto determine if there were electrical power saving opportunities at the main fan stations.A systems approach to electrical power savings was used to identify potential savings in the various components of a primary ventilation system. Furthermore, only technological interventions were considered to obtain electrical power savings. From generic technological driven electrical power saving strategies four energy savings strategies were identifi ed, namely potential overall reduction in ventilation volume, improved underground air utilisation, optimisation of fan-set effi ciency and potential fan drift design optimisation. The study indicated the colliery (say Colliery D, Shaft A) that showed most potential in the four technology driven energy savings strategies. A detail study was undertaken at Colliery D, Shaft A to increase the confi dence level and the study confi rmed that up to 45 per cent of the main fan absorbed power can be saved (475 kW) with an estimated capital payback period of 18 months. The study clearly showed that an integrated approach to optimise the entire mine ventilation system has great potential for power saving, and that a clear, well -defi ned methodology will be applicable to similar underground collieries. This paper discusses the background to the study and the process followed to implement the energy savings initiative at Colliery D, Shaft A."

Jun 1, 2012

By F Hungerford

"In-seam drilling has been undertaken for the past 30 years for gas drainage to reduce the risk ofoutburst and lower the concentrations of seam gas in the underground ventilation. The drillingpractices have reflected the standards of the times and have evolved with the development oftechnology and equipment and the needs to provide a safe environment underground. Earlypractice was to adapt equipment from other fields, but with changing emphasis, research anddevelopment by the coal industry has created specifi c equipment, technology and practices toaccurately place in-seam boreholes to provide efficient and effective gas drainage."

Jun 1, 2012

Goodenough and Fergusson Islands, in eastern PapuaNew Guinea, lie in an area of crustal extension on the western end of the Woodlark Basin seafloor spreading system. The islands are made up of a number of mountainous domes of complexely deformed basement, and these are intruded by large bodies of granodiorite. The domes are bounded by curved shear zones and faults dipping outwards at angles of around 25 to 45¦. The cores of the domes contain lower crustal rocks of eclogite and granulite facies, these rocks have undergone retrograde metamorphism in the outer sheared zones. Movement indicators on the shear zones indicate a complex moverm.-It geometry which does not fit the models proposed by earlier workers. These dome-like structures are similar to the metamorphic core complexes of the western United States Cordilleran region, however there are a number of aspects which do not fit with the models proposed for the development of metamorphic core complexes. Uplift of the metamorphic basement probably resulted from a combination of forces associated with the extension of the crust and the intrusion and emplacement of granodiorite plutons.

Jan 1, 1990

By Denby B

The ever increasing demand on land use has led to large areas of land being considered for development, which because of past mining activities are covered by substantial depths of fill materials. This paper examines the problem faced with the development of land infilled with open cast mining backfill, in predicting the behaviour of the fill upon development. To be able to design foundations suitable to withstand the movements that occur within open cast backfills or design a backfilling operation that produces land suitable for a proposed after development, a means of predicting backfill settlement is required. Factors critical to this prediction are the timing of backfilling operations, the compactive state of the backfill and the inundation of the backfill. The analysis of a considerable quantity of data collected from the monitoring of backfilling operations and backfill movement at a range of open cast coal sites located within the UK has given the authors a better understanding of how open cast backfills behave in terms of long-term creep settlement, collapse settlement and how these are effected by backfill scheduling. This knowledge has been encoded into a program running under Microsoft Windows that enables a user to make settlement predictions for a point, a given section or area or for the whole site. Differential settlements, critical to any development design, can also be determined between any two points taking into consideration the heterogeneous nature of open cast backfills. The program was tested with data from an open cast coal site in the UK. Compaction monitoring during the placement of the backfill material enabled a model of the backfill to be constructed taking into account backfill properties and scheduling. This model, taken as input into the program, enabled future backfill settlement predictions to be made. A comparison is given between these results and actual settlements obtained from a short-term settlement monitoring scheme.

Jan 1, 1995

Ulan Coal Mines Limited operates an underground and open cut mine near Mudgee in the Central West of NSW. The mines are part of a Joint Venture managed by Exxon Coal and Minerals Australia Limited (ECMAL). Currently all the mines output of over five million tonnes per annum is sold into the export market predominantly as a steaming product.

Jan 1, 1993

By Van Heuzen JA

The extensive deposits of brown coal in the Latrobe Valley form the major solid fuel resource in Victoria and are the energy source for most of the State's power generation. This paper describes the coalfield resources allocated for electricity generation and a potential sequential develop- ment of these areas in future years to supply future power stations.

Jan 1, 1982

The major copper orebody at Mount Isa is being extracted at a rate of four million tonnes per year. The method used requires an equivalent rate of back filling with (mainly) cemented fill. There were three major incentives for developing this mining system. The first was the prospect of high ultimate recovery of the orebody. The target is 100% recovery. Also the proposed stoping layout appeared to offer significant advantages in development and production costs. Finally, extensive subsidence above the northern end of the orebody could have disturbed permanent surface installations and jeopardised a possible future open cut. The full implications of this ambitious strategy were not apparent in the early years. Now, after twelve years of production the benefits are being realised and they can be weighed against the costs. Probably the most interesting result which comes from this analysis is the significance of cutoff grades and dilution factors in balancing mining and filling rates.

Jan 1, 1980

By James S. E

Financial risk of environmental problems is the key to many important business decisions within the mining industry. Massive uncertainty makes it difficult to choose a strategy for managing environmental problems to reduce corporate financial exposure to environmental impairment. A correct and practical method exists to clarify the risks and help make decisions. A case study on an insurance problem illustrates the method.The approach used is to translate existing data on environmental problems into probabilistic expressions of financial risk, and organise the expressions to reveal alternative solution strategies for the insurance problem.

Jan 1, 1993

By Fiedler VA, Threadingham GM, Leckenby DF, Clarkson CJ

The Utah Development Company Research and Development Laboratory has embarked upon a programme of optimisation of the company's coal preparation plants. This goal is being accomplished in a three-fold manner - use of pilot plant equipment for optimisation and modelling of the various unit operations, evaluation or development of on-stream ash analysis for process control, and evaluation or development of alternative processes. In each of these areas, digital data acquisition- and at a later stage, process control feedback, is being extensively utilised, based largely upon the use of the HP85 and HP9915 desktop computers. A variety of input/output configurations such as HPIB, BCD, GPIO are used, and at times supplemented by microprocessors such as the Intel 80/05 to assist in data transfer. This paper will discuss a number of specific projects, especially in relation to the manner in which the variables are monitored, and the data later retrieved and analysed.

Jan 1, 1983

Oxygen is required for the leaching of gold ores in cyanide solutions. The source of this oxygen demand and the effect of dissolved oxygen concentration on the rate of the process are briefly reviewed.A method of measuring the oxygen consumption rate is described and some experimental results reported.Fundamental aeration theory and rating of aerators is summarised to show how this type of experimental work provides the basis for full-scale design of aeration equipment.

Jan 1, 1984

By Pradhan GK

Blasting is one of the most important operations involved in surface coal mining. The removal of over-burden waste in surface coal mines of India had experienced many improvements in terms of blasting, explosives selection, blast design, equipment selection, deployment. etc. Two case studies of very large surface coal mines have particular importance in their blasting operations. Both these units have been equipped with large capacity excavating machines, hauling units and also have some difficult mining situations. Blasting is done in benches in close proximity to human dwellings and over coal seams developed by underground methods with problems of high wall stability etc, as well. The various steps taken to improve the blasting operations ensure smooth operation of the equipment to meet the targetted coal production.

Jan 1, 1991

The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

By Mayer TE

The Granites Goldfield is located 550 km northwest of Alice Springs. Mineralisation was discovered in 1900 and intermittently worked along nine km of strike until the early 1950's, yielding a recorded production of 470 kg of gold. The geological environ- ment, pre-existing exploration drilling results, and an optimistic view on gold, prompted acquisition of the property by North Flinders Mines Limited in 1975. An agreement was signed with the Central Land Council in August 1983 and drilling commenced in the same month. In the past, gold was won from alluvial deposits, rich quartz veins and lower grade, disseminated stratabound mineralisation. The last is contained within a distinctive unit in the Mt. Charles Beds, of the Early Proterozoic Tanami Complex. This informally named "Host Unit" is a metamorphosed, chemical- pelitic sediment. The schist contains variable proportions of amphibole, quartz, garnet, clinopyroxene, carbonate and sulphide, inter- calated with recrystallised chert beds. Free gold occurs in several mineralised horizons within the Host Unit, generally conformably distributed within lithologic bands or at lithologic contacts. The Host Unit occurs within a sequence of metamorphosed pelitic sediments and intermediate volcanics. Although mostly confined to the Host Unit, stratabound gold mineralisation also exists in both Footwall and Hanging Wall Schists, usually within zones displaying certain Host Unit characteristics. The deposits may be loosely categorised as being of banded iron formation (bif) type, although some important differences are noted between them and classical bif type orebodies.

Jan 1, 1984

By Kametani H

Since pyrite is a semiconductor, the relationship between the leaching rate and the semiconducting properties is of interest. In order to investigate this relationship, a pyrite concentrate (95% FeS2) was oxidized at 90¦C (363 K) in an acid solution containing 100 g/dm3 H2SO4 and 1.0 to 25.1 g/dm3 total Fe. The suspension potential (Pt vs. SCE) was maintained at the desired values, within the range 0.40 to 0.70 V, by controlled additions of a KMn04 solution during leaching. The results were analyzed using a simplified kinetic expression. The rate constant was independent of the Fe concentration, while it increased with suspension potential. Partly oxidized samples were then prepared at varying fractions of reaction. After removing the elemental sulphur formed, they underwent thermoelectric power measurements using a packed bed lying in a temperature gradient. The value of thermo- electric power increased from about 0 to 30 pV/K in the early stages of oxidation. The results obtained are compared with those for chalco- pyrite reported in a previous paper.

Jan 1, 1987