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By C T. Dunbar, P A. Walker, G E. LeJuge

A programme of blast improvement was initiated at the Mt Whaleback iron ore mine by BHPIO management in early-1998. One component of that work was the need to improve wall control blasting practices to better achieve the designed pit slope elements. This paper describes the geological conditions in which pit walls are developed, the mine operating equipment, the blast design concepts applied to minimise blast damage, the techniques applied in an assessment of the blast performance and the operational procedures developed to ensure that the blast concepts are effectively implemented in the production environment. Substantial changes have been implemented in both technical and operational aspects of the mining operation in order to achieve the improvements in pit wall condition, in particular recognising the need for a more flexible approach to limits blasting in response to highly variable and complex geology. The benefits to the mine are not only an improved wall condition, but increased confidence on the part of mine management that mine plans may be implemented on design and on schedule.

Jan 1, 2001

Many mining companies, by their remoteness of location from source of power, have to generate their own power and must experience the same problem that had to be met when deciding to increase the capacity of the power station. At present the Company is treating approximately 54,000 tons of ore mined per month, and the present shift average load. is approximately 8,500 kW. at 0.8 power factor, generated at the power plant, the observed peak load being 10,500 kW.It is proposed to increase the tonnage of ore treated to include 36,000 tons of copper ore, in addition to the present 54,000 tons of lead ore. The average load is estimated to be approximately' 16,000 kW. with a peak load of 17,500 kW. The estimate provides for power of 1,000 kW. to be supplied to the north end leases in the next 12 months, also for increased ventilation in the mines.There are installed in the main power station three turbo alternator sets each of 5,000 kW.; normally two sets are run in parallel and one set is a standby unit. A 12,500 kW. set is being installed and proposed loading with the increased tonnage will require the 12,500 kW. set and one 5,000 kW. set, or alternatively, the three 5,000 kW. sets When the 12,500 kW. set is down for service. When the original plant was installed some 25 years ago, the switches selected and installed in the main 3,300 V. power plant switchboard were rated at 150 MVA and the substation distributing centres located at the surface of the mine, in the mill, and in the smelter, were purchased as having a rupturing capacity of 100 MVA, and the stator...

Jan 1, 1953

By H Utama, hi, A Suw

PT. Indo Muro Kencana (PT.IMK) is gold and silver mine located in Central Kalimantan province, Indonesia. Mining activities in PT.IMK is conducted in Bantian pit area by applying surface mining method and using combination of excavator and hauler (articulated dump truck and rigid haul truck) as the transportation for ore to the crushing plant and waste material to the waste dump. Current blasting practice is ore-waste blasting. Ore-waste blasting is the term where the ore and waste rock are blasted in the same blasting process. Blasting is conducted by using nonel initiation system. By multiple pits operation, monthly powder factor is varied from 0.23 kg/t to 0.27 kg/t. Emulsion blend with density 1.15 g/cc is used as bulk explosive. At this stage, the concept of geoblast is proposed as an engineering tool for Drill and Blast engineering practice in PT.IMK. In addition, there is a need to maintain rock fragmentation by blasting, to maintain monthly powder factor, and to maintain excavator’s productivity. Next, the concept of scaled depth of burial (Chiappetta and Treleven, 1997) and the concept of blastability index (Lilly, 1986) are proposed as geoblast’s tools to improve blasting practice in PT.IMK. It is expected that rock fragmentation by blasting, explosive consumption and excavator’s productivity will be maintained by integration of geoblast and drill and blast engineering. Furthermore, the objective of this paper is to integrate geoblast and drill and blast engineering in order to create an engineering guideline in PT.IMK. Additionally, blasting trials with air decking application is proposed in order to support the geoblast’s improvement. It is planned that these blasting trials will be conducted in 2022. In conclusion, it can be seen that integration of geoblast and D&B engineering in PT.IMK is relevant to improve current drill and blast current practice and applicable to maintain rock fragmentation by blasting.

Nov 29, 2022

In the last 40 years nuclear energy has taken its place as a major source of electricity worldwide. It now produces 17 per cent of the world's electricity and could conceivably produce a higher proportion, to displace some six billion tonnes of carbon dioxide emissions per year. Concerns about global warming and environmental quality now underline the virtues of nuclear electricity among alternative sources of energy. Global electricity demand is rapidly increasing as a proportion of total energy usage. The proportion has doubled since 1960 and the demand is expected to increase at least 75 per cent between now and 2020. The source of this extra capacity, and the replacement of present capacity, raise questions with major resource and environmental implications. Today nuclear energy is a mature technology. Over 1200 nuclear reactors have been built and operated, some of these have been decommissioned, and among the 440 reactors in commercial operation the first advanced reactors are now entering service. Some 8000 reactor-years of operation have, with the sole exception of Chernobyl, shown nuclear energy to be extremely safe and reliable. High-level wastes are being managed properly and in different parts of the world two strategies are applied to this. Australia has a major role as a long-term supplier of uranium, since it holds almost 30 per cent of the world's reserves. This, along with an impending sellers' market for uranium, is making it an opportune time to develop new mines here. However, after several decades of concern about civil nuclear energy contributing to the arms race, we now have uranium liberated from nuclear weapons stockpiles being diluted for use in civil reactors, which will supplement ex-mine supply. The public acceptability of nuclear energy remains the critical factor in its future and hence in ours.

Jan 1, 1997

With the exhaustion of orebodies close to the main haulage shaft of the Emperor mine, an increased rate of development, aimed at earlier investigation of values disclosed by exploration drill holes has been attained with an overall reduction in unit costs.This paper describes the techniques used in rates of advance up to and exceeding 1,000 ft per 28-day period.

Jan 1, 1966

By A K. B Chigwada

Mining organisations grapple with the same problems year after year, wasting incredible amounts of time and money. According to estimates from the International Labour Organization (ILO), over one million work-related deaths occur annually, and hundreds of millions of workers suffer from workplace accidents and occupational exposure to hazardous substances worldwide. Many accident reports cite human failure as a primary cause (Busse and Johnson, 1998). The workers at the Bhopal chemical plant pumped methyl isocyanate into a leaking tank (Morehouse and Subramaniam, 1986). On 3 December 1984, more than 40 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal, India, immediately killing at least 3800 people and causing significant morbidity and premature death for many thousands more. The company involved in what became the worst industrial accident in history immediately tried to dissociate itself from legal responsibility (Broughton, 2005). Australia is not spared from safety problems either (Lucas, 2022). The ILO Convention 176 (1995) as a response provides that national law should inter alia provide for the supervision of safety and health in mines; the inspection of mines by designated inspectors of the competent authority; the procedures for reporting and investigating of fatal and serious accidents; the compilation and publication of statistics on accidents, occupational diseases and dangerous occurrences; the competent authority to suspend or restrict mining activities on safety and health grounds until conditions giving rise to the suspension are addressed; and worker consultation on matters related to safety and health in mines. This has assisted in getting enough data to define the magnitude of the problem to the mining sector.

Apr 16, 2024

This paper discusses recent ore reserve methodology at the Woodlawn base metal Mine in New South Wales. The ownership of the Mine changed hands in 1987 and a number of revisions to ore reserve practice were instigated by the new operators. While the overall modeling and calculation procedure remained essentially unaltered, the modifications and revised assumptions significantly increased the ore reserve. While general ore reserve procedures are discussed in this paper, it is the impact of these changed assumptions on the reserves which is our main focus.

Jan 1, 1990

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By B Putland, I Lovatt, D Schwann, A Cervillin

The Mount Carlton project in Queensland's North East sits on a high-sulphidation epithermal style deposit rich in gold, copper and silver. Mt Carlton is an open pit mining operation with ore processed using a primary crusher, single stage SAG mill and flotation to produce a concentrate for sale. Orway Mineral Consultants (OMC) was involved in the original design of the comminution circuit and the project was commissioned in late 2012, with first concentrate shipped in March 2013. When Evolution sought to optimise the project in 2015, OMC was invited to assist by undertaking a circuit review to identify opportunities for the optimisation. During 2016, the Mt Carlton site team implemented the optimisation strategies developed in conjunction with OMC. These included reconfiguring the SAG mill discharge arrangement, reducing the average ball diameter and allowing the mill to operate at higher speed and under more autogenous conditions. Cyclone operation was changed to constant pressure and the vortex finder size was decreased. The combined strategies improved energy efficiency and allowed higher SAG mill power utilisation. The additional power has been used to increase throughput by 2.4 per cent while achieving a 27µm reduction in product size (P80) to gain downstream recovery improvements. The reduction in grind size has been achieved with only 6.8 per cent increase in specific energy consumption because of a 6.5 per cent increase in grinding efficiency. The circuit product size is also notably more consistent due to the improvements made to the cyclones, providing benefit to the downstream flotation circuit. A significant decrease in ball consumption was also gained, saving hundreds of thousands of dollars a year in operating cost.This paper will discuss the circuit design, start up and will detail the changes made during the optimisation and why these were successful.CITATION:Putland, B, Lovatt, I, Cervillin, A and Schwann, D, 2018. Mount Carlton comminution circuit design, start-up and optimisation, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 517–528 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

Is your company paying taxation on profits which are partly illusory?ò Are unions making wage demands based on erroneous notions of the real level of value added to your companyÆs production?ò Do you receive historic data on profit contributions by different products, or for different market areas, which you feel may be misstated?ò Do you find that cash is not always readily available to pay dividends out of reported earnings because, it is required to finance additional working capital without a real increase in the level of activity?ò Are your planning and budgeting routines hampered by the need to rely on historic financial data which bear little resemblance to what the future may hold for your company?ò Are you able to maintain your business at its optimum operating capability or do you feel each year that it becomes more and more difficult to achieve the same volumes of prdduction at the same level of return on assets employed without having to raise more capital?If your answer to any of these questions is "yes", then it is very likely that Current Cost Accounting (CCA) has something to offer you!characteristics of the mining industry and for single venture mining operations.

Jan 1, 1984

By Williams RE, Ralston DR

Acid mine drainage is a serious environmental and economic concern, resulting in regulation of the mining industry and significant water treatment costs. An interdisciplinary approach is needed to analyze the many aspects of a complex acid drainage problem. This paper describes the integrated application of techniques from the following fields to the characterization of acid drainage at a large underground lead-zinc mine: 1) hydrogeology, 2) surface stream analysis, 3) structural analysis of fracture distribution, 4) hydrochemistry, 5) geostatistics, and 6) multivariate statistics. The Bunker Hill Mine in northern Idaho, is developed in highly fractured and faulted quartzites and discharges 95 L/sec of water with an average pH of 2.8 and an average zinc concentration of 120 mg/L. Research has been conducted on all aspects of the acid water production and drainage problem. Recharge to the mine has been investigated using geophysical techniques and tracer studies. Fracture mapping and geostatistical analysis of the fracture data have been used to determine characteristics of inflow to the mine workings. Hydrograph analysis techniques have been applied to water flow data within the underground workings. Chemical sampling and analysis have been used to identify acid producing workings, and better understand mechanisms controlling acid water production. Multivariate statistical techniques have been applied to analyze the quality and flow data. Research results from the many subprojects of the Bunker Hill study reveal the importance of an interdisciplinary approach to the analysis of acid mine drainage problems.

Jan 1, 1988

By J F. C L Costa, J C. Koppe, C Diedrich

Currently mineral resources evaluation is firstly expressed in terms of volume. Next the resources are transformed into tonnes by using an average bulk density applied to the whole deposit or, in some other circumstances, various different densities to distinct geological domains. Previous work in uranium, copper and nickel deposits used linear correlation between grades and bulk density to derive the density. Geophysics methods are also another good way to obtain density indirectly.These approaches do not take into account that two samples with the same grade but with different bulk densities can characterise different sample supports, leading to severe bias in grade and tonne estimates. It is important that the systematic measurements of bulk density are included into the estimation process, particularly when density is not correlated with the grades. Additionally, the extra time and costs involved in obtaining the bulk density data have made the mining industry disregard it.This study reports the impact in resource estimates by using a methodology that includes the bulk density variability. It involves the determination of a variability model for the bulk density and another model for the composite that was weighted by density as well as by its length. Next, these variables are estimated by kriging and the final grade estimates are obtained. The tonnages are obtained with the bulk density estimates. The conventional methodology was also applied and both estimates are compared to the reconciliation data from a major copper deposit. The results show a significant difference between the tonnage and grade estimates obtained from these two methodologies.The results show that considering density variability when compositing leads to a more accurate methodology resulting in better grade and tonnage estimates locally and globally.

Sep 26, 2011

By C McCracken, R Landers, B Hesse

Minnovare identified the potential to improve production drilling outcomes in underground long-hole stopes through the adaptation of new technology which was under ongoing development. An approach to Evolution Mining resulted in the companies agreeing to a collaborative agreement to further develop the technology for use on underground long-hole drilling equipment. During a period of six months in FY2018, a series of trials were conducted to compare drilling accuracy using two different methodologies and the subsequent impact this had on ore dilution. Testing was conducted at Cracow underground gold mine in Queensland, Australia. The drill rig’s existing setup/alignment process was compared to the new technology system with the following observations: • Using the existing process only 20% of holes surveyed recorded toe points within the +/ 300mm (11.8in) tolerance blast-hole deviation. • The new technology was proven to limit rig setup/alignment error, reducing average blasthole deviation and increasing the number of holes drilled within tolerance by 160%. The increased accuracy reduced stope dilution by reducing over-break of subgrade ore: • Stopes drilled using the new technology recorded 62.6% less average dilution. • This contributed to an overall reduction in dilution for the full year (FY18) of 5 percentage points compared to FY17 - from 22% to 17% (a net decrease of 22.7%). • With the system implemented as standard practice following results of the FY18 trial and continued success, overall dilution for full year FY19 showed continued reduction to 12% Evolution has continued use of the new technology at Cracow, where the improved accuracy has allowed the extraction of narrower stopes where drilling accuracy is critical. Evolution has also deployed the technology at the Mungari operation and has stipulated that the contractor use the technology at the Mt Carlton operation, which is currently under development. Future implementation of the Development Optimiser system should be verified by commencing additional trials to include a larger data base for validating the initial trial results.

Mar 15, 2021

By K T. Broekman, R L. Koenig

"The Braemar Iron Formation is atypical ore when compared to the current magnetite ores being processed. In attempting to process and economically recover the vast quantities of iron ore stored within the Braemar Iron Formation, æshifting the paradigmÆ is required. The formation has a low Davis tube recovery (DTR) grade of 15 - 20 per cent, which is much lower than magnetite ores processed in Australia. Despite this, by thoroughly testing and understanding the ore characteristics, it is found that the Braemar ores have significant advantages to processing than the harder banded iron formation (BIF) and taconite resources.The Hawsons magnetite iron ore resource has been known from the early 1960s when CRA explored the area. The grade was low and the Pilbara region discovery lead to the development of high-grade direct shipping hematite ores. Carpentaria Exploration (CAP) rediscovered the magnetite whilst undertaking multi-commodity exploration in the Broken Hill district during 2009. Shifting the paradigm away from grade the advantages of processing this ore are achieved by having an extremely low waste to ore ratio, lower Bond work index, lower abrasion levels and high-grade magnetite concentrates with little impurities other than silica. While developing the Hawsons Iron Project (HIP) it became more apparent that a positive business case is achievable when the following factors are exploited: very large resource - the resource is contained within one pit the rock fractures easily along grain boundaries - ideal for cheap impact crushing of the ore the ore is extremely soft, with a Bond work index of 6.3 - 8.0 kWh/t all major infrastructure required is readily available - rail, power, access and port the mine is in close proximity to Broken Hill - rich mining history and skill set available the resource contains many billions of tonnes of magnetite mineralisation.Shifting the paradigm by selecting equipment suitable for processing soft ores and not hard BIF or taconite ores and taking locality and available infrastructure into account may change the way people approach new low-grade resources in future.CITATION:Koenig, R L and Broekman, K T, 2013. Understanding ore characteristics and equipment selection, in Proceedings Iron Ore 2013, pp 403-410 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By P Mikula, B Darlington, J Graham, P Young

In underground mines experiencing dynamic events, there is an ever-present challenge to design and maintain a capable ground support system. One key component of ground support systems is surface support, which serves the essential roles of retaining failed rock and transferring forces generated by surface displacement to rock bolts or other support elements. Observations underground show that in many instances, standard mesh panels alone do not provide sufficient dynamic support to retain substantial bulking failures imposing displacement onto mesh, and in such cases Mesh straps and W-straps may be employed. Determining the performance of surface support elements proves to be difficult, with a multitude of variables at play in the underground environment. Quite comprehensive work has been completed on laboratory testing of surface support systems; however, very little work has been conducted on in situ dynamic testing of Mesh straps and W-straps. In 2019 in Western Area’s Flying Fox Mine, in situ dynamic testing was conducted on a series of Mesh straps and W-straps using Sandvik’s in situ Dynamic Test Rig (DTR). The testing regime applied impact energies from 5.1 to 15.3 kJ to Mesh straps and W-straps. The performance of the straps that did not fail was a maximum absorbed energy of 9.3 kJ and 14.2 kJ for the Mesh straps and W-straps respectively. The testing successfully demonstrated the ability of Sandvik’s DTR to test not only rock bolts, but also surface support elements, creating new testing and research possibilities. The testing also provided important design guidance data that is not practicable to obtain using laboratory dynamic testing facilities.

Nov 29, 2022

By L Boczek

The term Engineer of Record (EoR) is commonly used in North America and South Africa to define the responsible person for the design, construction and operational phases of a tailings storage facility (TSF). Recently, this role has been elevated in prominence within Australia, but what does it really mean? Recent updates to international TSF guidelines suggests appointing an EoR is good practice, but where does the responsibilities of the EoR start and finish. Interestingly, both Samarco and Mount Polley failures had active EoR’s in place. This suggests that nominating an EoR alone, is not the full answer to mitigating the potential for a TSF failure. Appropriate construction and operational practices are key to the success of the design of TSFs, where all too often, operators ignore the operating plans developed by the designer. To be successful, a key consideration of the EoR role, is involvement in the operational phase of the TSF. This requires ‘buy-in’ from the mine managers and a change in the way TSFs are perceived by site. This paper explores how the roles and responsibilities of the EoR can assist in improving governance of TSFs if implemented effectively and what role the client has to ensure the success of the EoR.

Jul 1, 2021

By J Field

Many aspects of water use in mining are driven by the technical requirements for water. There has been little consideration given to both the safety and the health requirements. Workers in the mining industry are exposed to water from a range of treated and untreated sources. The intended use of this water dictates the required quality of the water, sometimes with limited consideration for contact with miners. Particularly for underground workers, there is exposure while working in and walking through groundwater possibly contaminated by hazardous substances. Where controls are inadequate the outcomes of this exposure can result in disease, illness and injury û the costs of which can be significant. The situation could also arise where, due to the lack of human exposure, the controls are unwarranted and the financial cost unjustified from a health perspective but warranted from an equipment management standpoint. In addition to the health aspects, water can impact on a range of safety issues resulting from high pressure usage, dust suppression, fire fighting and other processes. The protocols and procedures in place need to consider the safety issues in addition to managing water usage. The current state of water management in mines from an occupational health and safety perspective has been ascertained from a survey targeting underground and surface coal and metalliferous mines. This survey considered the health and safety issues associated with water use, the types of surveillance, control protocols and the strategies that the mines have in place to manage the health and safety risks associated with water systems. The results assisted in the identification of potential occupational health and safety risks associated with water systems and the management processes that may be appropriate from a risk management perspective. Health and safety issues are often neglected but remain critical issues affecting the value of water to the mining industry.

Jan 1, 2006

Probabilistic seismic hazard analyses (PSHA) have now gained wide acceptance in the development of design criteria for major projects. When used with regional criteria the procedures have also allowed the preparation of more rational seismic zoning maps. Seismic zoning maps using various levels of results from PSHA studies around the Pacific Rim now include Canada, Indonesia, New Zealand and the United States. Some Pacific Rim countries such as Chile where the seismic exposure is dominated by subduction events have no subdivision into separate zones.Approaches to risk based zoning are being considered in several Pacific Rim countries including Australia. Australian studies must face problems similar to parts of the Eastern United States where seismic activity is low with irregular and infrequent occurrences of moderately large earthquakes. The perception of the seismic exposure by both regulatory agencies and the public at large is different when considering areas of low seismicity. There is therefore a need to make different interpretations of the results of PSHA studies in these areas of low seismicity. The aim of this paper is to explore some of these differences by comparing the results from two site specific studies from areas with widely differing seismic activity rates.

Jan 1, 1990

By Reichman J. P

Extensive use is made of a small scale computer (IBM 1130), in the calculations of ore reserves for Western Mining Corporation's nickel mine at Kambalda, W.A. All surface drilling data such as assays, density and location information, are stored on disk files at the Company's Technical Computing Centre at Perth, W.A. The computer is used to search through the data, select significant ore intersections, calculate the area of influence of each intersection and perform the necessary calculations to arrive at an estimate of the ore reserve. Comparing the computer-assisted ore reserve calculation with an entirely manual operation, it is estimated that a saving of 40 percent in time is achieved together with

Jan 1, 1973

This paper is for mine managers. It is about maintenance of mining equipment. This is an extremely broad subject so this paper is given with the caveat that it necessarily contains generalisations, not true in all cases, but broadly correct. The job of mine managers is to be good at making money from the excavation and preliminary treatment of mineral. To do this well, they need to understand the cost and value drivers in the business. This includes understanding the drivers associated with maintenance. Maintenance is often identified as a problem at mine sites. It is frequently listed as the cause of production shortfalls when reporting. The state of maintenance within mining as an industry is generally among the lower end of the range, when compared to manufacturing, petrochemicals, etc. Why is this? Experience and review of many audits and evaluations of maintenance has shown that some patterns are consistent with good performance and some consistent with poor performance. These often centre around the time horizon of the management team and are associated with knowing the sensitivity of the business to certain maintenance drivers and the mechanisms of maintenance and their results. To summarise, some common misunderstandings can be listed as statements that are obvious and extrapolations from those, which are not necessarily correct. For example: High availability of equipment is necessary for production. Incorrect extrapolation:focus on availability will produce high production. Design is often the greatest factor in determining the reliability of a mining machine. Incorrect extrapolation: the newest and biggest machines generally have the lowest cost operations. Operation has an enormous impact on machine productivity and reliability. Incorrect extrapolation: the fastest operators are generally the best from a productive point of view. Some maintenance improves the performance and reliability of machines. Incorrect extrapolation: more maintenance will give you more reliability. Some maintenance depends on disassembly and reassembly of components. Incorrect extrapolation: assembly is basically the reverse process of disassembly. Maintenance improvement in the mining industry in the last 15 years has focused largely on planning and systems improvement. Incorrect extrapolation: most of the problems in maintenance can be traced to a lack of planning. Actions based on flawed extrapolations will steer a business suboptimally. It is therefore important that the mine manager understands these issues so that the improvement effort can be directed to the greatest benefit.

Jan 1, 2006