Search Documents

Ore reserve estimates form a basis for strategic mine planning at Argyle Diamonds open pit and alluvial operations. Most ore reserve statements are mainly concerned with resource tonnage and grade. Because diamond deposits are low grade, high value resources, diamond quality ($/carat) is also an important parameter. Relatively large variations in quality and/or grade can occur. These variations must be taken into account before the resource potential can be fully assessed. Computers (HP9000 and PC's) are utilised to compile resource inventories. Resource inventories are then ranked on an economic basis. This paper discusses the methods used to compile resource inventories and explains how these are then used to present ore reserve estimates in terms of resource potential.

Jan 1, 1990

The need to estimate the block size distribution of a jointed rock mass is of great importance in the design of blasting rounds to attain a pre- established fragmentation. Other Geomechanics topics, such as ,hydraulic behavior of rock-masses, as well as the determination of their strength properties, also require the accurate prediction of a rock-mass composition in terms of block size taking in due account the three dimensional interference of joints and other geologic discontinuities. In this paper, a method for computing the block size analysis of a jointed rock mass is described, using as input the common geologic data (dip and strike) of fracture planes existing in a rock bench prior to blasting.

Jan 1, 1977

By Hunter GW

This paper gives an account of the filling system at Mount Isa from surface fill production to stope discharge underground. A brief explanation of the surface facility and reticulation is given prior to the discussion on aspects of underground reticulation. These include fill hole types, pipe and breastplate installation, wear characteristics, etc. The different types of fill and their respective applications is mentioned as a prelude to a general overview of the mining considerations associated with fill placement and its role in the long term planning strategy at Isa Mine. Some practical aspects of stope preparation and filling procedures are outlined for the various stoping methods. Finally a brief outline of future fill developments is given.

Jan 1, 1982

By A B. Bayooke, A C. Robertson

In terms of underground tunnelling in metres advance per capita, Australasia compares well with the best world performers. This is because of the large number of metalliferous mines, coalmines and civil tunnelling projects, with the Australian tunnel advance for civil and mining projects exceeding 625?km/a. In terms of hard rock quarry extraction, Australia produces approximately 200?Mt/a of aggregates, roadbase, fill material and specialist rock products from its quarries, which equates to approximately 8?t/capita. Australian mining and tunnelling contractors are also of world standard and are used to excavating in a variable range of ground conditions in a competitive environment. One author has been involved in tunnel and underground space planning and quarrying in Australia for the past 25 years and predicts that, over the next 20 years, there will be a major swing towards underground space for commercial uses. This paper identifies the potential uses of underground commercial excavation and the planning and geotechnical challenges for the future. Underground quarrying creates new opportunities to extend existing quarries within their urban footprint with minimum impact on the surrounding community. Investigations by the authors reveal that there are very few cities in the world that actually incorporate underground space planning in their city plans. However, cities such as Helsinki have been planned in detail to utilise the rock resources beneath them. Brisbane is used as a case study for a practical application of commercial underground space and underground quarrying in Australia.CITATION:Bayooke, A B and Robertson, A C, 2014. Geotechnical challenges for underground commercial space and quarrying in Australia, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 317–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Xstrata CopperÆs Mount Isa Copper Operations is located in mineral rich north-west Queensland and is one of the largest sources of copper in the world. This world-class underground operation is planned to produce over 6.6 million tonnes of copper ore in 2007 from the X41 and Enterprise Mines. With an underground mining history of over 50 years and underground reserves of over 83 million tonnes at 2.6 per cent copper, mine planning for the future becomes an exciting challenge for the technical team due to the older nature of certain areas. The 1100 Orebody of the X41 mine was one of the first places that copper mining occurred, with its discovery in 1953 - 1954 and mining commencing in the 1960s. Sublevel open stoping mining methods have been employed since that time as the means of extraction, using a primary-secondary sequence to maximise stope turnaround time. Large Transverse Pillars within the 1100 orebody were not mined out in order to provide access for ventilation, power, orepasses and other services. The Panel Pillar, 4180XC and 4010XC pillars are three such Transverse Pillars in the 1100 orebody that will be mined as a final retreat. This paper discusses the technical challenges and issues associated with the extraction of Q390 stope, one of the stopes located in the Panel Pillar, and the design solutions to overcome these issues. Managing the exposure of backfilled stopes of variable fill strength, ensuring the stability of the crown, stope walls and drawpoints, managing vertical openings, re-establishing service networks, and stope filling are the critical issues given consideration for the final design of Q390 stope and other such stopes within a Transverse Pillar. Communication and coordination between the different departments in the mine are essential for the necessary work to be completed in a timely manner to bring pillar stopes into production.

Jan 1, 2007

By R Hao

Uncertainties in large open pit geotechnical modelling has been a major concern for slope stability analysis. The level of confidence in the in-put assumptions, such as structural and rock mass model, dictates the modelling results to some extent. This article is to detail a case study of Kalgoorlie Consolidated Gold Mines (KCGM) regarding a predicted inter-ramp failure on an as-built pit walls by a 3D numerical modelling. Significant concerns were raised across site and multiple preventive plans were considered. After intense data collection work, it was confirmed that the risk of failure had been overestimated. The case study has improved the understanding of geotechnical data in-put and has enhanced the process of creating and updating geotechnical structural models at KCGM.

Jun 22, 2022

By C Sylvestre

For the last 50 years, traditional safety management has improved safety performance by: • Fixing the environment (eliminating the hazard). • Improving the system (more/less rules, procedures etc). • Making safety more conscious (more/better interactions about the importance of safety). Although these approaches certainly have merit, and may be part of an overall solution, they are not enough to prevent many modern-day incidents. Today, these three approaches are used more than before, and are used better than ever before. Yet, workplace fatalities in Australia have stagnated from 2013 to 2019, as have the number of incidents, even serious ones. In the USA, workplace fatalities have increased by 15 per cent in the same period.

May 5, 2022

By J D. Tolley

The shift towards clean energy technologies is having a significant impact on the mining industry, with the demand for minerals such as copper, nickel, cobalt, lithium, manganese, and graphite increasing exponentially. To meet the goals of the Paris Agreement, mineral requirements for clean energy technologies would need to quadruple by 2040, and to achieve net-zero globally by 2050, mineral inputs in 2040 would need to be six times more than today. The most significant driver of mineral demand is electric vehicles (EVs) and battery storage, with lithium seeing the fastest growth, and copper demand doubling over the same period due to the expansion of electricity networks globally. The demand for these minerals is expected to rise significantly as investments in clean energy technologies continue to grow in the future. As the world moves towards a decarbonised economy, the minerals industry is under increasing pressure to reduce its environmental and social impacts and meet the increased demand for minerals. Mining companies are facing additional challenges due to the depletion of near-surface mineral deposits globally, with more mines transitioning from open pits to underground. The transition to underground mining requires the right strategy to economically access deeper mineable inventories and to keep up with future clean energy technology demands to achieve net-zero globally by 2050. One key way to achieve this is through decarbonisation using ‘green’ mining technologies such as replacing current primary diesel mining fleets with battery electric vehicles (BEVs). However, these measures through electrification overlook the bigger opportunity to maximise the socio-economic returns from the mine while also reducing the overall carbon footprint. Corporate cut-off grade policy is one of the most significant influencers on the total environmental and social impacts of the mining industry. The purpose of a corporate cut-off grade policy is to implement strategies aligned with achieving all the mining companies’ corporate goals, with decarbonisation targets becoming a primary driver for mining companies. Table 1 shows the evolution of cut-off theory with the increasing number of dimensions and driving inputs per iteration.

Aug 2, 2023

There is an increasing demand for refrigeration as mines progress deeper. Mine refrigeration plants have special requirements in terms of their duty and application. There are no national or international standards applicable for the testing of these plants. There have been numerous examples of plants failing to meet their required nominal capacity, but with the plant owner being unable to enforce the design duty on the manufacturer, due to a failure to unambiguously specify testing or accepting criteria. This paper discusses some of the reasons for performance shortcomings and describes a methodology for developing and specifying performance criteria, when inviting design and/or construction tenders, and a method of performance and acceptance testing once the plant has been built and commissioned. These guidelines encompass the full range of performance duties expected from a mine plant, including stable operation at maximum and minimum plant capacity, and under the various combinations of extremes of high and low condensing and evaporating pressures. A description of a methodology for developing a computer-based mine refrigeration plant model is also presented as part of the performance testing criteria. The methodology is illustrated with reference to the actual performance and acceptance testing process used on the worldÆs largest bulk air cooler (R67) at the Enterprise mine at Mount Isa, Australia.

Jan 1, 2005

By Y Cui, G Cao, H Zong, J Zheng, J Wang, S Yue, J Zhao, B Li

The iron (Fe) concentration in nickel slag is high, making its recovery and utilisation a hot and challenging topic. In the nickel smelting process, using CaO instead of SiO2 to adjust slag’s composition, and then directly reducing Fe from the output of molten slag is a more feasible method in practice for Fe recovery in nickel slag. The adjustment of slag’s composition in the nickel smelting process will have an impact on the distribution of impurity elements such as Pb, Zn, and As. In this paper, the slag adjustment of nickel smelting process was carried out with the oxygen-enriched topblowing system. The distribution of impurity elements in the smelting products with each composition slag was conducted by using thermodynamic software. Experimental verification was performed with rich oxygen top-blowing, and the distribution characteristics of impurity elements in the smelting products were characterised to explore the differences in mineral phases of impurity elements with each smelting conditions, elucidating the distribution patterns of Pb, Zn, and As in each phase. The results indicate that after slag adjustment, impurity elements are more easily to volatilisation and removal into the gas, reducing their total concentration in slag and matte. In the slag, the existence form of Pb, Zn is changed from silicate to ferrate, and As is changed from arsenate to low-valent arsenic oxide. It is easier to decompose the impurity-containing mineral phase and remove the impurity elements in the subsequent iron extraction process.

Jun 19, 2024

By McMahon D

The approach to valuations at the Normandy Poseidon Group is a measured and methodical process that utilises skills sourced from a number of different disciplines. Whilst being subject to a strict set of guidelines, it is also sufficiently flexible to be able to cope with the considerable variety across the resources industry. The group uses Discounted Cash-Flow (DCF) techniques extensively in order to develop a base valuation. Other external factors (eg the market) are, however, also taken into account when forming a view on value. Other methods of valuation are used in tandem or as alternatives depending on the task. DCF techniques are an important tool but would never be used in isolation. Considerable care must be given to developing the DCF analysis as its components (eg discount rate) are prone to misuse. Whilst the valuation process is quite detailed and scientific, it is really only as good as the inputs or assumptions (technical, financial, etc) that are used. The methodology used remains consistent whether the group is undertaking the corporate planning process or making an acquisition.

Jan 1, 1994

By Falbo A, Barbaro M, Esposito MA, Passariello B

Acidic reductive leaching is one of the best known and most widely employed chemical processes for beneficiating minerals of industrial interest. Conventional acidic leaching with sodium dithionite (Na2S2O4), employed to bleach industrial minerals used in the production of ceramics, glassware, paper etc, does not always allow products of high quality to be obtained. In the work reported here two reducing agents, ascorbic acid and oxalic acid, have been employed in a medium acidified by means of sulphuric acid. Continuous systematic tests have been performed on a kaolin sample containing 0.8 per cent Fe2O3, adopting various operating parameters such as, leaching time, temperature and reagent concentration. In each case the total quantity of bi- and trivalent iron dissolved was ascertained. Removal of 80 per cent and 100 per cent of iron with ascorbic and oxalic acid respectively was obtained, while less than one per cent of iron was dissolved in the presence of sulphuric acid only. Products having a very good degree of whiteness (92 - 94 per cent) were obtained, whereas with sodium dithionite the degree of whiteness was in the 85 to 88 per cent range. The best conditions identified were applied to a sample of quartz for the removal of ferric impurities.

Jan 1, 1993

The Kaltails Project is situated close to the city of Kalgoorlie-Boulder in Western Australia. Located on the south-eastern fringe of the Golden Mile, Kaltails has been in operation since June 1989. The tailings forming the reserve for Kaltails have been derived from 100 years of underground mining on the Golden Mile, but, some of the re.;erve has been retreated in the past. A map of the tailings reserves and treatment plant site is presented as Figure 1. The gold project is a joint venture between Poseidon 90 per cent and Gold Corporation (ten per cent) and is managed by Poseidon Gold Kaltails.

Jan 1, 1992

By Akerkar D. D, Dey M. L, Mathur S. B, Chowdhury S. K R

The extraction of gold and silver from chalcopyrite concentrates has been investigated. In view of the recent interest in non-cyanide leachants for gold and silver, one such alternative reagent, namely thiourea, has been employed in the present work. Precious metal leaching was attempted from received copper concentrates as well as pre-oxidised concentrates. Pre-oxidation of the concentrates was carried out by three different methods, namely roasting, pressure oxidation and biological oxidation. After pre-oxidation and leaching of the base metals, the leach residues were subjected to further leaching for precious metal extraction. The results obtained on the extraction of gold and silver from received concentrates as well as pre-oxidised concentrates are presented and the effectiveness of the three pre-oxidation routes employed is compared.

Jan 1, 1992

By I Jabouri

There are many physical factors that can affect the self-heating rate of coal. The presence of seam gas has often been referred to as inhibiting coal self-heating due to the limited access of oxidation sites created by the presence of the gas adsorbed on the coal pores. Similarly, the presence of bed moisture in the coal also acts as an inhibitor of oxidation by blocking access of air into the pores. Gas drainage of a coal seam prior to mining removes both gas and moisture from the seam. Bulk coal self-heating tests in a two-metre column on both gassy, as-mined and gas-drained, dried high volatile bituminous coal show that removal of gas and moisture from the coal accelerates the rate of self-heating to thermal runaway from 8.5 days to 4.25 days, from a start temperature of 30¦C, with an airflow of 0.25 L/min. The corresponding gas evolution pattern for each of these situations is different. Therefore, it is necessary to take this change in coal condition into consideration when developing a spontaneous combustion management plan.

Jan 1, 2005

By D R. Seaman, Y Peng, F Burns, D J. Bradshaw

Telfer Gold Mine is a gold-copper mine in the eastern Pilbara of Western Australia, owned and operated by Newcrest Mining Limited. TelferÆs ores are processed by a dual train, 21 Mt/a, concentrator where gold is primarily recovered by gravity concentration and the flotation of a gold-bearing copper concentrate. A minor portion of TelferÆs gold is also recovered to a pyrite concentrate that undergoes treatment via carbon-in-leach (CIL) cyanidation. The gold recovery of the CIL circuit is below the industry standard and operates with a high reagent consumption rate.With a new fine-grinding facility, the Telfer process plant will have the ability to liberate copper and gold from the pyrite concentrate and recover these by flotation prior to the existing leaching circuit. This process will improve overall gold and copper extraction, while reducing reagent consumption in the CIL circuit.This article is an overview of the development of this methodology. Size-by-size analysis and mineralogical studies of monthly composites identified factors limiting the CIL gold recovery and the causes of high reagent consumption. Laboratory studies confirmed a relationship between the regrind product size and gold leach recovery. The addition of an intermediate flotation stage ensured that the regrind circuit will improve overall recovery while at the same time reducing operating costs. Without the addition of a flotation stage, the additional reagent consumption from regrinding alone would be prohibitive towards increasing recovery. Pilot scale studies confirmed the conditions required to selectively recover gold and copper from the pyrite concentrate as well as establishing the full scale regrinding energy requirements. Construction of this facility at Telfer is currently underway.CITATION:Burns, F, Seaman, D R, Peng, Y and Bradshaw, D J, 2012. Development of a pyrite regrind circuit at Telfer Gold Mine, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 45-52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By B Besa

Australia is a world leader in the design and operation of mines accessed by the decline method. Literature indicates that a number of metalliferous underground mines using the decline system are also increasing steadily. This increase has generated a great deal of interest in underground haulage systems in future due to the huge costs involved in the development of declines. Studies have also shown that the current method of accessing orebodies by the conventional decline method has proved to be expensive, especially for narrow vein deposits. This is because decline development costs are influenced by mine planning and design parameters as well as available haulage systems that the mining engineer can choose from. The current access method suggests that more waste material is being extracted because of the size of decline openings adopted (5.5 mW and 5.5 mH). Also the conventional 1:7 decline gradient and turning radius of 20 m makes decline lengths, as well as the duration of development, excessively longer. This paper discusses results of a mine design case study with monorail technology as a method of accessing and developing the decline. The proposed system is economical, has high advance rates and offers a significant reduction in capital expenditure. The study compares costs, development metres and the duration of decline development using the monorail system with the conventional (truck haulage) access method. Results obtained indicate that the monorail technology has the potential to reduce the decline length by over 62.6 per cent and decline costs by 63 per cent for the case study. The monorail system also reduces the total capital development costs by 22 per cent for the same case study. Due to rapid development resulting from increased advance rates and the shorter decline length coupled with smaller decline openings, the time to access the deposit reduced by 71.8 per cent. This case study demonstrates that the economics of narrow vein deposits can be improved significantly by using the monorail system of decline development.

Jan 1, 2008

By P Gehrke, S O’Gorman

The precise measurement of NO2 was historically difficult in road tunnels, hence criteria and design analysis was based on converting from NOx concentrations via a set NO2:NOx ratio. The reliable direct measurement of NO2 is now possible, however design analysis is still dominated by emissions tables and formulas specified in terms of NOx. For converting from NOx to NO2 in a road tunnel environment in Australia, the ratio has typically been assumed to be ten?per?cent. This has generally been based on the recommendation in PIARC (2000) and on the ‘average’ value cited in PIARC (1995).Determining this ratio is important as changes in engine technology and in-tunnel pollution criteria along with improvements in CO and particulate emissions control, may mean that NO2 will become the driving factor for future ventilation requirements. Correct selection of this ratio can directly impact the ventilation capacity and system design.Recent research has indicated that choosing a constant ratio of ten?per?cent for all tunnels may not be appropriate. The in-tunnel ratio has been estimated to be as much as 20?per?cent to 30?per?cent and depends on the location in the tunnel, the type of ventilation system and the traffic/fleet characteristics. This paper discusses the effect of some of these parameters on the NO2:NOx ratio in road tunnels.The findings indicate that the ten?per?cent upper limit on the NO2:NOx ratio in PIARC (2000) may be a conservative value for design purposes for longitudinally ventilated road tunnels of typical length in Australia. A value of seven?per?cent to eight?per?cent may be more appropriate in some circumstances. However, the value chosen will depend on the specific tunnel in question and the confidence in traffic conditions expected. Values above ten?per?cent may be encountered for short periods but usually when the NO2 levels are low.CITATION:O’Gorman, S and Gehrke, P, 2014. NO2:NOx ratios in Australian road tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 95–102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R Beaulieu, D Burlingame, C Hanks

The Ekati Diamond MineÖ is CanadaÆs first diamond mine and is located 300 kilometres northeast of Yellowknife in the Northwest Territories. The development of the mine supports sustainable development through the integration of environmental, economic and social considerations with the broad aim of minimising environmental impacts while maximising opportunities and benefits to northern residents and northern businesses. The environmental assessment and regulatory processes for the Ekati Diamond MineÖ were the most extensive seen in the NWT to that date; in Canada only uranium mines receive more attention. In addition to the regulatory requirements, an Environmental Agreement was negotiated with the Governments of Canada and the Northwest Territories to address environmental concerns not covered by existing legislation and regulation. Under the agreement an Independent Environmental Monitoring Agency was set up to oversee the regulatory process and implementation of the Environmental Agreement. Environmental stewardship is implemented through an Operational Environmental Management Plan, part of which includes effects monitoring programs for wildlife and aquatics where available traditional ecological and scientific knowledge are integrated to broaden our understanding of the tundra environment. A Socio-economic Agreement was concluded with the Government of the Northwest Territories to maximise employment and business benefits to the north. Voluntary and confidential Impact Benefits Agreements (IBAs) were also negotiated with four Aboriginal groups who use the area where the mine is located. The intention of the IBAs is to foster development initiatives and a partnership thereby helping to insure that benefits from the project flowed to the Aboriginal groups despite a lack of settled land claims in the region. All these were completed before commercial production in October 1998. Employment targets of 62 per cent residents of the Northwest Territories and 31 per cent Northern Aboriginal have consistently been met thereby ensuring benefits flow to residents of the Northwest Territories. In 2000, $316 million was spent to support operations at the Ekati Diamond MineÖ. Of this, 82.2 per cent of total spending and 26.6 per cent total northern spending was northern and northern Aboriginal businesses, respectively. The environmental and socio-economic monitoring results are reported annually to the responsible government agencies and potentially affected Aboriginal groups. To date, there have not been any significant adverse environmental effects documented and socio-economic targets have been met.

Jan 1, 2002

By Toro HCH, Von Borries GH

A brief description of the semi-autogenous grinding (SAG;) facilities of Compania Minera Disputada de Las Condes is given. A data-logging and computer system was connected to the plant inter facing the existing analog control system in a supervisory s, control philosophy. The development of a control straiov,v t,) maintain maximum power of the SAG mill atsubjected to process restrictions is shownThe present control scheme is discussed inalgorithm was designed based on correlations onLween vartaoles. Associated with this, a direct level of control was developed be, on classical control algorithms, process inter-active tuning has been included. Also, an algorithm to prevent overloading of the is discussed. Control scheme tests are presented in comparison t manual operator control under the same conditions. It is shown t the control strategy gives a more stable operation and a higher plant throughput.

Jan 1, 1985