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By S Agdaca

Leightons is the sole contractor at the Wahana Coal Mine Project (part of the Bayan Group), a multi-seam thermal deposit consisting of 13 coal seams with thicknesses ranging from 20 cm to 500 cm. The average dip of the deposit is 18 - 20°. However the deposit is heavily faulted in certain domains with anticlinal and synclinal structures present causing seams to dip up to 90°. Average thickness of coal inter-burdens range from less than 2 to 12 m. The minimum coal thickness being mined is 20 cm. Coal production is direct mine mouth feed and there is no coal processing plant currently used.Conventional blasting between the highly variable coal horizons in the early phases of the mine life was suboptimal from a production perspective. Drilling short holes with a reduced drill pattern, and on occasions with sloping benches, resulted in low drilling and explosives loading efficiency.A high frequency of small size blasts fired up to two times daily was required with each blast consisting of four up to five small blast areas. Each blast averaged approximately 36 000 bcm thus causing a low utilisation rate of the mining fleet from frequent blast delays and the inability to deploy larger Liebherr 9350 excavators on bench. It was identified that increasing the production targets required a more efficient drilling and blasting process. Furthermore, due to the highly variable nature of the deposit, the existing coal model was determined to not be able to accurately predict the coal seam location prior to blasthole drilling.In August 2009, Leighton Contractors Indonesia and Orica Mining Services with the full support of the Wahana team, initiated through seam blasting trials using electronic blasting systems. Further trials were conducted in November 2009. Trial evaluations indicated that the benefits from decreased lost time events due to blasting, an increased vertical advance rate per blast, and increased overall blast size could be attained while not damaging or diluting coal.Full-scale?through seam blasting has been ongoing since February 2010 for the upper eight coal seams to extract coal seam thicknesses ranging from 20 - 100 cm. This paper will discuss the parameters of the through seam blasting process in Wahana and the resulting benefits to the overall mine production.

Nov 8, 2011

A new bench blast design method and its realization with the assistance of the computer is introduced. The basic design principle is to define a rhomb cell, called fully- fractured zone, through a series of full scale bench crater tests and apply this geometric pattern in multi-hole, multi- row blast design. To illustrate the design method, the optimization process and assessment of blast performance are presented in the context of a case study.

Jan 1, 1992

Sample preparation for gold samples, where the distribution and size of gold particles is often irregular, usually demands that a relatively large sample weight is taken to produce a representative sample for analysis. Traditional sample preparation of gold samples incorporated multiple stages of coarse particle size reduction followed by subdivision of the sample prior to final fine pulverising. This technique developed because of the limited equipment options available to laboratories. As a result significant errors are introduced and the final sample size being pulverised is a small fraction of the original sample weight. Three significant developments have occurred in the last 25 years to significantly improve sample preparation of gold samples: 1.  large capacity fine pulverising,2.  fine jaw crushing, and3.  whole sample coarse pulverising. In the mid-1980s an Australian manufacturer developed large capacity pulverising bowls which had the ability to reduce samples with a mass of 1.5 - 3.5 kg to a nominal 0.075 mm product in approximately three to five minutes. Laboratories were able to produce a large homogeneous pulverised sample which significantly reduced the error in sampling. However, exploration and mine samples are usually 7 to 10 kg and the sample requires a subdivision stage following crushing to produce the 3.5 kg for the pulverising step, thus introducing potential for significant error. The development of fine jaw crushing allowed particle size reduction to -2 mm which reduced the subdivision error of the bulk sample prior to fine pulverising. Subdivision of the crushed sample at -2 mm still results in potential sampling errors, where the gold particles are not sufficiently liberated to be representatively sampled. Clearly the best option would be to reduce the particle size small enough to ensure a representative sample prior to final pulverising. Continuous mills offer a partial solution but are relatively slow and subject the sample to differential pulverising prior to subdivision. Clearly this does not provide the best solution for routine laboratory applications where high volumes of samples are to be processed. The recent development of a large capacity coarse pulverising system allows samples of up to 10 kg to be reduced to -0.25 mm prior to subdivision, and fine pulverised to -0.075 mm. Laboratories now have the necessary equipment to perform reliable large capacity sample preparation of gold samples. The exact choice of a sample preparation scheme may still depend on particular ore types but the need for multiple crushing and subdivision stages is redundant.

Jan 1, 2008

The Gold Ridge Mine is an open-cut gold mine in the Solomon Islands. The mine is owned and operated by Gold Ridge Mining Limited, a wholly owned subsidiary of Ross Mining NL. At the invitation of the Solomon Island Government, project construction commenced in July 1997 and gold production commenced in August 1998. The mine is the countryÆs first, and represents a major milestone in the development of the Solomon Islands. At the time of project approval and construction, there was a growing awareness in the country of the potential impacts of mining in the tropics, partly due to unfavourable publicity surrounding a number of other mining operations in the Pacific region. The management of environmental impacts was therefore an important consideration in the approval of the project, and continues to receive a high level of attention from the Government and community. Ross Mining did not commit to the Gold Ridge Project until it had satisfied itself that all waste rock and tailings could be safely contained on-site, and that the standards normally expected of a mine in Australia could be met. Ross Mining approached the approval, construction, and operation of the Gold Ridge Mine with a set of operating principles that met Government and community concerns. These were:best practice environmental management; operation of the mine in accordance with standards expected of mining operations in Australia; independent peer review of key technical aspects; on-going consultation with Government and community; and equitable transfer of wealth to landowners and the local community. As a consequence, the Gold Ridge Mine has developed into a successful mining operation with a high level of support from local landowners, the general community and the Central and Provincial Governments of the Solomon Islands.

Jan 1, 1999

By O Handayani, R Barr, E Isaaks

The mining industry has focused a great deal of attention recently on the impact of blast movement on grade control. Although the problem of blast movement and its contribution to dilution and ore loss is well known, solutions to the problem are less than satisfactory. Perhaps the most recent innovation is the application of blast movement monitoring (BMM) devices to quantify blast movement. These devices emit an electronic signal and are planted at surveyed locations within the preblast material. Following the blast, their new locations are found using an electronic scanner. The magnitude and direction of the blast movement is given by the vectors between the pre- and post-blast BMM locations. However, it’s not clear how the BMM vector data can be best used to minimise dilution and ore loss. One common solution is to displace preblast dig line polygons by distances indicated by the BMM vectors. However, studies of BMM vectors show that blast movement not only displaces material laterally but also mixes material internally within the bench (Thornton, 2009a).This paper presents a method for modelling the post-blast muck pile that accounts for displacement and internal dilution using simulated annealing. The preblast ore control block model is re-blocked to 1?×?1?×?1?m sub-blocks. Each sub-block is displaced by simulated BMM vectors conditional to post-blast surface topography and blast initiation sequence data in addition to BMM vector data. The displaced sub-blocks are aggregated into new ore control model blocks whose grades are calculated from the contained sub-blocks. New dig lines are then designed on the post-blast muck pile model using the new ore control block model grades. A case study based on actual data is provided.CITATION:Isaaks, E, Barr, R and Handayani, O, 2014. Modelling blast movement for grade control, in Proceedings Ninth International Mining Geology Conference 2014 , pp 433–440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Paterson M. R, Spencer P. A

Vitrokele technology is a resin process that can be applied in gold plants to reduce both capital and operating costs. The Vitrokele resin can be used for both precious metal recovery and for recovering free and combined cyanide from effluent streams. Vitrokele resin has been extensively tested at pilot plant level and is now applied successfully at a commercial heap leach facility in Zimbabwe where it is used in place of activated carbon for recovery of gold from pregnant leach solution. Significant capital cost savings were achieved by installation of a resin plant instead of a conventional carbon adsorption plant. Operation to-date has not seen any significant physical or chemical degradation of the resin either in terms of adsorption capacity/kinetics or physical appearance/size. This gold recovery process is equally applicable to slurry streams where it would be implemented in stirred tanks with interstage screens in a similar manner to a conventional carbon adsorption plant.

Jan 1, 1996

By S Robertson, I Buitrago

Mine life cycle planning and enduring value are taking centre stage to meet corporate goals and deliver socio-economic outcomes for communities over the life of a mine. There is a general agreement in the literature about mining-induced effects on locals adjacent to mining operations and subsequent closure. In response, international regulatory bodies, through the implementation of global agendas, encourage exploration and mining companies to embrace the concept of corporate social responsibility. This concept is designed to provide sustainable outcomes and maintain a social license to operate over the life of a mine. This paper proposes a practical application of the sustainable livelihood approach as a tool for international planning. With this approach as the governing framework, this paper proposes an innovative tool for mine life cycle planning. Based on the findings, this paper discusses the socio-economic impacts of mining and mine closure. It also argues that transferring some of the benefits from mining to create lasting value for communities needs to be considered at the initial stages of planning for the mine and the community. Findings also indicate that conditions such as a strong local government, good governance arrangements, relevant capacity-building for sustainable livelihoods and a diversified economy are important to transferring some of the benefits from mining to create lasting value for communities. The paper is based on a mixed research technique for data analysis and a case study methodology. The case studies were conducted in Australia and Colombia.CITATION:Buitrago, I and Robertson, S, ?2014. Mine life cycle planning – creating lasting value for communities, in Proceedings Life-of-Mine 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By E Widzyk-Capehart

The conventional ammonium nitrate fuel oil (ANFO) loader utilises a pneumatic system to control the flow of ANFO (via rotary actuator/ball valve) and air (via an auxiliary air valve). This system, though relatively simple and reliable, has several drawbacks with respect to ease of control and level of automation. In this paper, a radio frequency (RF) remote control for explosives charging is discussed. The system design incorporates electric solenoid valves to control the rotary actuator and the auxiliary air valve. All operations associated with explosives charging are selectable at the remote and are completed according to a modifiable time sequence. This allows the following charging sequence to be reduced to a single momentary application of the remote:removal of water from the hole prior to charging with ANFO; charging of the hole for a preset but adjustable period of time; and removal of the remaining ANFO from the ANFO hose. A specially developed remote switch allows the operator to maintain two-handed control of the ANFO hose whilst achieving full control of the charge-up process. Failsafe electronic architecture is incorporated into the systemÆs design to increase safety to the highest level. Should the RF remote control fail, a wired remote is included in the system to allow for the charging process to continue, albeit at a reduced level of control. The application of the RF remote control system in an underground explosives charging operation minimises and/or eliminates many problems associated with the use of the conventional charging system. These include: the wet-hole problem, trip and entanglement hazards, air embolism and the two-man loader control requirement. The developed remote control unit proved to be effective at removing water from wet holes leading to increased face advance per drilling operation. It proved to be economically feasible, allowed for an increase in systemÆs dependability and safety factor and for a truly one-man operation which resulted in reduced manpower.

Jan 1, 1999

Responsibility for the administration of mineral resources is divided between federal and provincial governments. The paper traces the evolution of mineral policies at both levels of government, from the end of World War II to the present. In the immediate post-World War II years, the emphasis was on supplying the raw material needs of a rapidly growing world economy. Policies favouring growth and development of the Canadian mining industry were instituted during this period. Two decades of uninterrupted expansion (the 1950s and 1960s) ensued. The decade of the 1970s was a turbulent one for Canadian mineral producers. Governments intervened more substantially than ever before. Moreover, the industry suffered from an intense period of competition for resource revenues by the two levels of government. At the same time, far reaching changes were taking place in the structure of world mineral markets. To date in the 1980s, the mineral industry has, perforce, adapted to existing mineral market structures. Mineral policies, too, have shown signs of adapting to the needs of the mineral industry. Whether the resulting mix of policies will permit the revitalization of the Canadian mining sector remains to be seen.

Jan 1, 1986

This paper deals briefly with three of the more controversial aspects of the geology of the Mount Isa ore deposits namely the geologic structures, the method of ore deposition and the origin of the ore.In the section on geologic structures, an outline is first given of the purely tectonic deformation advocated by the early authors. The current interpretation, which differs in the proposed order of events and causal forces, is then discussed. Other concepts, which attribute all or part of the deformation to sedimentary features or preconsolidation movement, are outlined ilnd commented on.The remaining two sections deal mainly with the better known lead-zinc orebodies. In the first of these a brief description and criticism is given of the early interpretation which was based on the deposition of successive waves of mineralisation which replacedindividual beds in the shales. The current ideas, which visualise emplacement of the ore between the beds rather than replacement of them, is then discussed. The final section develops the case for a sedimentary origin of the lead-zinc ores and broadly outlines the author's ideas concerning the evolution of the Mount Isa ore deposits.INTRODUCTIONAny consideration of the geology of Mount Isa must begin with the work of Blanchard and continue with that of Hall. Individually, or as co-authors, they published various papers on the geology of Mount Isa. Of these, the best known is their "Rock Deformation and Mineralisation at Mount Isa" (1941) which gave a comprehensive account of all aspects of Mount Isa geology.It is necessary to appreciate the limits set on geological knowledge of the mine and environs in 1941 by the extent of mine development and regional geologic studies. Underground, 7 level (897 ft.) was the lowest producing level. Development on 8 (1073 ft.) and 9 (1247 ft.) levels consisted only of exploratory drives and crosscuts in the vicinity of the Davidson Shaft. The tops of the 650 and 750...

Jan 1, 1961

By S Lloyd, J Chow, S Fitzpatrick, D Greenup

The Tropicana deposit was discovered in 2005 after AngloGold Ashanti followed up an unexplained gold-in-soil anomaly. Discovered in a remote, barely-explored area of Western Australia not previously thought prospective for gold, Tropicana is the most significant gold find in Australia for more than a decade. The new, large scale open pit gold mining operation will produce an annual production of around 330 000 to 400 000 oz over a ten year mine life mining around 60 Mt/a.Process plant construction started in early 2012 and is due to finish in the December 2013 quarter. The mining contract was awarded to Macmahon Holdings (Macmahon) and mining commenced in July 2012 using conventional drill and blast, truck and excavator open cut methods.As a construction and start-up project in a greenfields location, the establishment of mining activities at Tropicana Gold Mine (TGM) involves the implementation of technical and operational systems, including the mining contract. Some of these systems and likely challenges were identified during earlier studies, while others were not foreseen until they were encountered. Alternatively, the time frames around implementation change depending on the changing knowledge of the project and industry environment. These systems include those common to the industry and those specific to the operation and location.This paper examines the implementation and development of a number of the systems specific to the establishment of mining operations, including the history, process and some outcomes. Although expected to be discrete systems to implement, they become interdependent. This linkage between systems further offers challenges and opportunities for the continuous progress of each system and for TGM as a whole.CITATION:Chow, J, Fitzpatrick, S, Greenup, D and Lloyd, S, 2013. Tropicana Gold Mine - mitigating the challenges of a mining start-up, in Proceedings World Gold 2013 , pp 51-60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Teleoperation is one method by which an operator can remotely control and monitor a vehicle. The operator monitors the status and progress of the remote vehicle by watching the video transmitted from one or more cameras which are mounted on the vehicle. In the case of an LHD, it will be fitted with three cameras. For a twin-boom Jumbo, four cameras are mounted on the drill, three of which will have remote pan, tilt, 15x zoom, focus and lens cleaning controls. The advantage of teleoperation is that an operator can stand in the drive and send the remote vehicle around a corner, completely out of sight and still clearly see what is happening. This means that an LHD returns with a full bucket and a Jumbo can be operated from a safe distance. Standing in the drive teleoperating vehicles, exposes the operator to passing traffic including the remote vehicle. There are two solutions to this problem. One is to equip the operator with a Nautilus æBuddyÆ jacket which will help to protect them from all vehicles. The other is to move the operator into a safe room or area, away from the fumes, the noise and the traffic. In this comfortable, less stressful environment, the operator will be more productive and less likely to accidentally damage the vehicle. The operatorÆs æsafeÆ room does not have to be a formal control room, it can be any area which has AC or DC power available and is large enough to contain a chair and a 1.5 m x 0.75 m table. The æsafeÆ room can be on the surface or underground, it does not matter to the operation of the Nautilus Equipment. If the LHDÆs, trucks, locomotives, etc are automatically guided from origin to destination, the operator is free to operate several vehicles at a time, performing only those tasks which are too difficult for a computer to do by itself.

Jan 1, 1998

The introduction refers to observations made in the early days of the Nationalisation of the Coal Industry in the United Kingdom, indentifying the underground transportation problems. Statistical information is presented, highlighting the considerable developments which have been made in recent years with an evaluation of the manpower and cost involvement.

Jan 1, 1985

By Jaczkowski B. M, Cox T. J, Domfeh I. A, Stalker I

Mining and treatment of gold ore in the Ashanti region at Obuasi, Ghana has been continuous for more than 100 years. Earlier production from this world class deposit can be traced far into the history of West Africa's gold trade. As part of a general development and expansion program, Ashanti Goldfields Corporation (Ghana) recently undertook a program to heap leach oxidized near surface ore. Kappes, Cassiday & Associates was given a major role in the design, equipment supply, installation and start-up management of the 3000 tonne/day heap leach. Unusual conditions included a high annual rainfall and an ore which could be characterized as a soft, decomposed, water saturated schist. Production began in March 1990. Startup problems and their solutions are discussed.

Jan 1, 1991

By A Melloy, D Holt, M Jurak

Oaky North is AustraliaÆs highest producing underground coal mine. In 2011, the mine produced 8.7 Mt of high-quality coking coal. The high quantities are a result of the constant strive for optimising the operating time of major production units, which involves investing numerous resources, including diesel equipment, in supporting and maintaining their operation.In July 2011 it was identified that the diesel particulate matter (DPM) levels in the underground workings were above acceptable levels, due to the high level of diesel activity. Over the next 12 months, several controls were implemented to reduce exposure to personnel: the main ventilation system was upgraded; the production forecast was adjusted to better manage the diesel fleet, removing surges in diesel usage; and an electronic diesel tag board was introduced to centrally manage the distribution of diesel usage around the mine.From the start of the campaign in emission reduction, an intense DPM monitoring regime was established. Within a few months of the introduction of the centralised tag board, there was a major reduction in emission levels. After the installation and commissioning of the new main fans, the emission levels dropped further, such that over-exposures are now a rarity.Oaky North continues to explore new systems to better utilise their diesel fleet while still maintaining control over DPM emissions.CITATION:Melloy, A, Holt, D and Jurak, M, 2013. Reduction in diesel particulate matter at Oaky North, in Proceedings The Australian Mine Ventilation Conference , pp 187-190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By P Voigt, B Lumsden, P Lines, I Gurnett

Plant tests of magnetic conditioning have shown increased flotation recovery of paramagnetic sulfide minerals (chalcopyrite, sphalerite and pentlandite) in the -38 ¦m size fraction within rougher and cleaner flotation circuits. A statistical plant test was undertaken in the Mount Isa zinc flotation circuit where magnetic conditioning was tested simultaneously in both the rougher circuit and the cleaner retreat circuit (cleaner scavenger). This test resulted in a normalised increase of 1.60 per cent in the rougher circuit zinc recovery and simultaneously a normalised increase of 4.60 per cent in the cleaner retreat circuit zinc recovery - to a very high level of statistical confidence. Interestingly, in a novel approach, it was possible to verify the plant test results in two ways. Firstly, detailed MLA analysis of the tails confirmed the statistical plant test results and showed that the greatest effect of magnetic conditioning was on the sphalerite in the C3 - C6 size fraction, where there was a reduction of around 15 per cent in zinc in tails. Moreover, there was a reduction of around 15 per cent in liberated sphalerite across all -38 ¦m size fractions, but only a seven per cent reduction in non-liberated sphalerite in the tails. Secondly, plant modelling showed that increasing the rougher zinc recovery would cause an increase in zinc feed grade to the cleaner retreat circuit. The increase in the zinc feed grade to the cleaner retreat circuit with magnetic conditioning was demonstrated to a very high level of statistical confidence.CITATION:Gurnett, I, Voigt, P, Lumsden, B and Lines, P, 2012. Magnetic conditioning of sphalerite at XstrataÆs Mount Isa Zinc Operations, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 233-240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Szwedzicki T

Uniaxial testing was performed on model pillars to determine the effect of width to height ratio on pillar and surrounding rock mass stability. Samples were modelled in a shape similar to that of dumbbell weights, with the centre representing

Jan 1, 1994

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

Jan 1, 1988

By Keast-Jones R

The relative merits of treating coal by flotation and spiral concentrators have been examined by tests on run-of-plant fines samples from three seams in the Wittingham coal measures of the Upper Hunter Valley. Flotation of the complete fines was found to be the most metallurgically efficient process with yields substantially superior to those obtained from treatment of only the deslimed fines. A strict comparison between spirals and flotation for the treatment of the deslimed fines was impossible due to differences in product quality. However, the results indicated that the performance of a flotation circuit would be equivalent, and sometimes superior, to that of a spiral circuit.

Jan 1, 1984

Over a four year period from 1984 to 1987, a broad range of ground conditions were experienced in recovering old workings at the Walhalla mine in central-eastern Victoria. Access to the ore zone was gained via old workings and new development. The work included: Recovery of vertical and inclined shafts. Recovery of collapsed winzes. Recovery of level drives and crosscuts. Spiling through broken ground and old mullock. Pre-grouting of caved zones. New development using small-scale rail equipment and "bobcat" Loaders.

Jan 1, 1988