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Longhole stope overbreak has always been a source of unwanted cost within the underground mining industry, and efforts to control it using various rock reinforcement systems have long been a rock engineering challenge. At the Pasminco Mining Broken Hill Operations trials have been carried out using an innovative cable bolt reinforcement system known as Rib-Roc. The system, based loosely on the Swedish Rib-in-Roc concept, utilises zones or ribs of heavily reinforced rock in the troublesome hangingwall and back areas of longhole stoping. The trials were carried out under a strict qualitative and quantitative scientific stope measurement program utilising rock mechanics instrumentation. Not only did the trial demonstrate the success of the system but data obtained was useful in implementing the system virtually as standard practice throughout the operation.

Jan 1, 1995

By D Thornton, B Smith, S Demey

Mine to Mill (MTM) optimisation, a total systems approach to the reduction of energy and cost in mining and mineral processing operations, is well-established technology. However, successful applications of MTM optimisation have been largely confined to gold, copper and lead/zinc semi autogenous grinding (SAG) operations, where the goals of tweaking the blast design to increase fines and hence throughput through the mill have been relatively easy to meet. The application of MTM optimisation in a more demanding environment, like that of a multi-stage crushing and screening aggregate operation, was conceived as part of a Department of Energy (DOE) initiative in 2004, aiming to reduce the energy consumption in the US aggregates industry. Two quarries operated by the Luck Stone Corporation of Richmond, Virginia, were selected for the demonstration sites. Dealing with ore variability and a requirement to maintain a fixed feed size distribution to the tertiary plant, whilst still aiming to increase yields of saleable products, presented some unique challenges. Despite these variables, the implementation of the MTM approach at Luck StoneÆs aggregate plant in Pittsboro, North Carolina, has led to a tangible improvement in productivity, particularly in the primary and secondary plants. The successful outcome was dependent upon several key factors, including reliable blasting and processing models, careful analysis of the rock conditions and plant configuration, understanding and buy-in from the Luck Stone operations staff, excellent collaboration with Virginia Tech staff and students, and long-term monitoring made possible through comprehensive PLC logging. This paper presents a review of the work conducted at the Pittsboro quarry and highlights the key reasons behind the successful implementation of the MTM approach in a complex plant environment.

Jan 1, 2007

By Poplawski R. F

A 32-channel PSS seismic monitoring system was commissioned at Mt Charlotte mine in 1994, and at the time it was the first such system in Australian mines. The system continuously observes the occurrence of seismic events and locates them accurately in space and time. Mt Charlotte has a history of seismicity, with the largest event in recent years of Richter magnitude 4.3. The decision to 'go seismic' was made despite some uncertainty regarding its potential usefulness. However after the first year of operation, benefits have been realised in terms of less production downtime, improved mine safety and mine planning, and better understanding of the nature of Mt Charlotte seismicity. The seismic network has performed well, recording 550 events in its first year of operation to a location accuracy averaging ¦ 12 metres. System reliability is excellent, with very little downtime, and acceptable operation and maintenance times and costs. Observations show major distinct changes in the rate of mining induced seismicity over time periods of weeks and months. Events have tended to cluster in specific mine areas and on particular faults and structures. Case examples of pillar preconditioning, breakout around an orepass, and a major stope rockburst, illustrate the role of seismic data and the benefits it brings to safety, productivity and planning.

Jan 1, 1995

The Fiji islands are the world's most ac- cessible Cenozoic remnant arc. They provide occasional subaerial exposures of an arc frag- ment some 750 km long and 80 km wide, or about the size of the NE Japan volcanic arc. The fragment is one part of the former Vitiaz Arc which once connected Fiji to Vanuatu and Tonga. The Fijian portion has the most completely stu- died Tertiary section which contains a history of arc volcanism from the late Eocene to late Miocene (the Early and Mature Arc stages), a rich diversity of subsequent magmatic responses to the most recent episode of arc rifting (Ear- ly Rifting stage), and an example of transition from arc to intraplate volcanism as this rift- ing proceeded (Late Rifting stage). The arc fragment is surrounded by younger backarc ba- sins. The chemical composition of magmas in both the arc and backarc changed with time, but in opposite directions. In the arc, magmas be- came enriched in sialic components from the Early Arc to Early Rifting stages, whereas in the basins the magmas became more similar to mid-ocean ridge basalts (MORBs) with time. In southwest Fiji, the oldest backarc basin has subducted obliquely beneath the remnant arc du- ring the last 3 Ma, resulting in chemically ex- otic calcalkaline volcanism. During the last decade over 150 radiome- tric age measurements and 650 rock analyses, many with trace element and isotopic measure- ments, have been obtained for samples from Fi- ji, Tonga, and the surrounding seafloor (Figs. 1 and 2). These data are summarized, drawing from the publications of Colley and Hindle (1984), Gill et al. (1984), Hawkins and Melchi- or (1985), Kroencke (1984), Malahoff et al. (1984), Scholl et al. (1985) and Whelan et al. (1985), from the specific research papers refe- renced therein, and from the half dozen or so manuscripts currently in preparation by these people and others.

Jan 1, 1987

By Stitt P. H

This paper provides a brief historical review of the invention of the spiral separator and its adoption into Australian metallurgical practice. The purpose of the review is to demonstrate that spiral development to date appears to have been a largely empirical process, and that the cur- rent resurgence of interest in the spiral, especially in the coal industry, warrants an increased fundamental research effort. Current research work concentrating on empirical modelling is outlined, while some preliminary experimental results of a more fundamental nature are presented and some research of other disciplines interested in particle transport introduced in order to stimulate further work and discussion.

Jan 1, 1988

By S Gannon, J Abols, T Hughes

In the past year, two very innovative gold ore processing plants have been designed, built and commissioned by Gekko Systems Pty Ltd. The first plant in Vietnam utilises conventional crushing and ball milling followed by gravity concentration (Inline Pressure Jig (IPJ) and Falcon concentrator), flotation, intensive leaching (GFIL), the first industrial scale use of AuRIX«100å ion exchange resin and a cyanide destruction circuit. The second plant, in Australia, uses a three-stage crushing circuit to crush the gold ore to minus 1 mm, followed by gravity concentration utilising a rougher, scavenger, cleaner circuit of IPJs and a Falcon concentrator. A direct smeltable gold concentrate is produced as well as a lower grade concentrate for future intensive leaching or sale. Both plants were designed and built within very tight time frames and budgetary constraints. The experience gained during the plantsÆ design, commissioning and operation are discussed.

Jan 1, 2006

By M J. Kelleher

CREAM is an acronym for coal recovery, evaluation, analysis and management and is a business improvement project at BMAÆs Goonyella Riverside mine that is focussed on maximising coal recovered. In August 2003, Goonyella Riverside was set a challenge to quantify coal loss and dilution and their relationship to cost, revenue and ultimately profit. While the mine was confident in its site forecasts of recovery (and loss), it was clear that the traditional measurement and analysis systems were inadequate to firstly, identify key loss areas and mechanisms and secondly, successfully quantify the benefit of various coal recovery initiatives. The path that BMA Goonyella Riverside has travelled to maximise coal recovered can be divided into four key steps: Mapping the process û This step involved the development of a coal flow process map for Goonyella Riverside that stepped through each component of the process from the coal reserve to the customer and identified key measurement points for the purposes of reconciliation. Understanding coal loss and identifying opportunities û This step involved conducting two detailed Reserve to Customer projects at the mine site to track a block of coal from the reserve to the customer and to gain a greater understanding of the relationship of dilution, coal loss mechanisms, revenue and costs associated with recovering additional coal. Coal data systems development û Two important coal data systems have been developed and implemented at Goonyella Riverside in the past twelve months, namely SnowdenÆs Coal Reconcilor and SeamFix. These systems enable coal losses and dilution to be quantified and reconciled back to the initial coal reserve. Implementation of loss reduction initiatives û This step involved the formation of a business improvement project referred to as æCREAMÆ in August 2004, for the purposes of improving pit coal recovery and maximising business value. To date a series of coal recovery trials have been run in a number of pits at Goonyella Riverside that have yielded significant improvements in business value. The key to the success of this project has been the discipline to follow a defined process map, management commitment through resourcing and shared key performance indicators, a successful acceptance strategy resulting in holistic ownership and the implementation of sustainable reconciliation systems. Coal loss and dilution are now quantifiable and their relationship to cost, revenue and ultimately profit is well understood. This paper discusses the process that Goonyella Riverside has adopted to maximise coal recovered.

Jan 1, 2005

Pyrrhotite is the predominant gangue mineral at Renison comprising about 60 percent of the sulphides in an average ore blend. It exists as two crystal structures - monoclinic and hexagonal. Monoclinic pyrrhotite is the slowest floating of all minerals but is ferromagnetic and hence recoverable more efficiently by low intensity magnetic wet drum separators than flotation. This paper discusses the installation and commissioning of four 0.915 m x 3.0 m, 0.1 Tesla permanent magnet, wet drum separators prior to sulphide roughing flotation. Planned circuit and process control modifications to better accommodate magnetic separation into Renison's flowsheet will be Discussed.

Jan 1, 1991

By Sauer P

The features of Banana screens have been known for some considerable time and recently considerable interest has been generated in the performance of these units. This paper reviews screening principles on Banana and conventional units and demonstrates the capacity and effic- iency of these units. Furthermore, the behaviour of modern Banana screens and modem screens in general, are examined with respect to life, vibration isolation, noise emission and maintenance requirements.

Jan 1, 1978

By Brien R. J, O&apos

Faster and more efficient methods of producing and refining iron and steel are imposing severe conditions on the refractory materials used to contain these metals in the molten state. In order to provide refractory linings which will give the desired service life and maintain unit availability at an economical level, it is necessary to appreciate the aggressive environment in which the refractories operate and determine the reaction mechanisms by which the refractories are destroyed. Only by such studies can the most suitable refractory or refractory combination for a particular unit be selected. Examples of refractories selection and reaction mechanisms are discussed for blast furnaces, BOS vessels, AOD vessels, steel ladles, vacuum degassing units and continuous casting.

Jan 1, 1976

By Dunn P. G

The copper ore reserves at the Chuquicamata mine were re-estimated during March to June 1994, as part of a comprehensive audit of the mine's overall short- and long-term planning. The basic principles essential to all ore reserve estimates were implemented viz: 1. A detailed study of the geology, in this case particularly of the orientations of structural features of copper mineralisation and the subdivision of the orebody into geologically homogeneous sections, 2. the use of both drillhole and blasthole data sets, 3. statistical and geostatistical analyses of both data sets to model anisotropic spatial structures for all the geologically homogeneous sections, 4. block kriging using both data sets individually; and 5. a comprehensive validation of the block valuations to confirm the absence of global and conditional biases and to quantify the actual improvement achieved in the overall quality of the estimates compared to those executed on earlier techniques.

Jan 1, 1995

By Jensen B

The investigation of the explosion characteristics of nine Bowen Basin (Central Queensland) dust samples in a suitable coal dust explosion chamber using a new dust concentration probe provides several advances in the area of coal dust explosibility testing. The 20 litre explosion chamber, of novel design, uses rotation of the main body of the chamber together with air jets for dust dispersion, and allows testing of different types of explosion initiators and analysis of the explosion characteristics of coal dust/methane mixtures of varying concentrations.A new development was a dielectric dust probe for the measurement of coal dust concentration. A capacitive micrometry technique was successfully adapted to measure dust concentration. The system uses a ratio-transformer bridge for measurement of small changes in a capacitive probe designed to sample a representative volume. The device is accurate, and is capable of operating in the hostile environment within the explosion chamber.The explosion chamber and dust probe characterise the explosive potential of coal dust samples by determination of the dust lean limit concentration in varying mixture with methane. Plots of lean limit points obtained in this way present an explosion curve for each sample which indicates the potential of the coal dust/methane to explode under the conditions of initiation in the chamber. The explosion curve obtained for each sample presents a unique signature that appears to reflect the physical and chemical characteristics of the dust.The results from this series of laboratory experiments appear to provide a useful index and indicate potential areas of interest for future research.

Jan 1, 1991

By Williams SR

Column Flotation cannot be used indiscriminately. Based on extensive pilot plant experience at Lakefield Research, a number of limiting parameters have been identified for the application of column cell flotation. Parameters of importance are the use of wash water, flotable mineral content, pulp viscosity, type of mineral selectivity being sodght and degree of mineral liberation. The paper discusses when wash water should be used and the positioning of a column within the circuit as this is important to maintain a sound water balance for the circuit and prevent excessive circulating loads. Other areas of debate are pulp chemistry, very low and high weight recovery, for which the conventional column is a poor selection of equipment, and treatment of complex ores, where the separation of valuable minerals is more difficult than non-sulphide, sulphide mineral separation. Based on these observations, the application of column flotation must be carefully considered or can be optimised.

Jan 1, 1993

By Erepan P. C

Flash flotation technology was introduced by Outokumpu in 1985. Considerable success was achieved in other plants with similar operations to OTML. Conclusions from site visits and amenability tests performed on plant samples were that the OTML

Jan 1, 1997

By A Robertson

Australia has been slow in adopting the use of underground space as a part of our urban planning process. Australia has one of the highest levels of tunnel advance per capita per annum in the world, yet the use of underground space in our cities appears difficult for our planners and politicians to comprehend, not withstanding the general availability of good quality rock and contractor expertise in Australia. However, the lack of space in our urban areas is being highlighted as our major cities expand outwards and people and businesses gravitate towards city centres. Typical potential underground space uses include car parking, self-storage and archiving facilities, water storage, underground quarrying, small industrial facilities and another layer of traffic (electric and fuel cell) and services network. Historically, blasting in high density population areas has resulted in blast vibrations and blast overpressures exceeding the limits, which in some case have been set extremely low in terms of peak particle velocity (PPV). This makes conventional blasting difficult, often requiring low charge weights per delay and associated small blast sizes and slow advance rates. However, the introduction of new technologies, such as computer aided drilling, electronic delays and low-energy explosives has made this task considerably easier. Although more expensive than conventional blasting, excavation by blasting using these products and technologies in relatively good quality ground is believed, in most cases, to be less than the cost of mechanical excavation. In this paper, the authors look at innovative trends in underground quarrying, underground commercial space and tunnelling and put forward their concept of future excavation demand, future product requirements and technical specifications to the drill and blast community.

Jan 1, 2007

Pan Australian Mining lid installed a milling and gold leaching plant designed to process 2 million tonnes per annum of breccia sulphide ore. This plant was commissioned in January 1989. Since commissioning, increased ore reserves have been established and the plant has been expanded by the addition of one ball mill and several tanks to increase the design capacity to 3 million tonnes per annum. This additional plant was commissioned in May 1990, bringing the total number of mills up to three, each 4.5 m diameter x 7 m long. The paper details how milling rates have been increased at the expense of grind size to increase the capacity of the original plant from 2 million to 3.1 million tonne per year rate before the additional ball mill was Commissioned.

Jan 1, 1991

By Grant JR, McKavanagh BM, Dear SJ

A geophysical technique of rock mass assessment for engineering purposes is being investigated and shows positive correlation with direct structural logging and mapping techniques for the detection of major geological features. The technique is cross-hole acoustic surveying incorporating high speed signal averaging, with a maximum hole separation in excess of 30 metres in hard unfractured rock masses. The bulk of the field test work was carried out in open stopes in the copper ore bodies of Mount Isa Mines Limited. The investigation forms part of an integrated study of blasting in mining, aiming for fragmentation control through blast design modification. The rock quality factor, Q, is presented as a blasting index and can be determined for a significant portion of a production stope.

Jan 1, 1981

By Yanagase T, Nakamura T, Ueda Y

The possibility of removing the phos phorus and sulphur contained in steelmaking slag has been studied by observing directly through the microscope melts heated on Pt- filaments. After a CaO crystal was placed in the molten slag, distributions of P, S and other elements formed around the CaO crystal were determined with the aid of EPMA. The results indicated that a layer of 2CaO SiO2 is formed on solid CaO in CaO-Si02 melts. Then between CaO and the newly formed compound the molten slag tends to migrate through cracks. For higher Fe 2 03 contents, the layers of the compounds 2CaO.Si02 and 3CaO SiO2 formed around the CaO crystal are not continuous but look more like particles, which promotes the dissolution of CaO. Phosphorus in slag was found to be enriched in the 2CaOòSi02 layer. Phosphorus in the 2CaO SiO2 phase is not related to the primary slag composition, being about 5-7% P205.. Sulphur in slag,as well as the phos- phorus,was concentrated in the 2CaO.Si02 phase. Disintegration due to weathering observed for slags produced in these investigations appeared to be due principally to hydration of lime.

Jan 1, 1980

Sublevel open stoping was introduced at Rosebery in 1972; most of the stoping prior to this was horizontal cut and fill. Sublevel open stoping presently accounts for 65% of the Rosebery underground production of 560 000 tonnes per year. This primary stoping technique leaves 50% of the ore in the crown and transverse pillars. The methods used in pillar recovery to date are reviewed and comments made on the success of these operations.

Jan 1, 1982

Pillar mining methods at the Pasminco Mining Broken Hill Operations are not new. Since mining commenced on Pasminco's leases at the turn of the century virtually every pillar extraction method tried throughout the world has been used. Much of the remaining mineral resource in the Pasminco Broken Hill leases is contained in pillars.However, due to the on-going need for mechanisation with bulk mining methods, and the very peculiar physical circumstances surrounding the formation of these pillars, their exploitation requires the development of a virtually new method based on excavation technology not previously used in the Australian mining industry. Trials of the method are to take place at the southern operations during 1991.

Jan 1, 1992