Search Documents

By L M. Zhang, T H. Xu, J Zhao

Blasting is one of the most commonly used strategies for excavation in civil and mining engineering. Yet blasting can also bring along such undesirable effects as ground vibrations and soil disturbance. Numerical analysis is a powerful tool for estimating the effects of blasting and improving blasting design. In this research, a constitutive model for sand is proposed for the numerical analysis of blast-induced ground motions and wave propagation in soil mass. In the model, three model surfaces, ie the critical surface, the dilatancy surface and the bounding surface, are defined following the bounding surface hypoplasticity framework. The strain rate is included explicitly into the model formulations so that the proposed model is valid under high strain rate loadings caused by blast-induced vibrations. The performance of the proposed model is validated by the simulation of drained triaxial compression tests conducted on a crushed coral sand under different strain rates.CITATION:Xu, T H, Zhang, L M and Zhao, J, 2014. A bounding surface model for sand subjected to blast-induced vibrations, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 201–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By J Koshy, M Ralph, P Foley

Mining in the state of Western Australia (WA) formally commenced in the 1840s, and over the ensuing 180 years has evolved to be the epicentre of the Australian mining industry and a significant contributor to the national economy. The lithology of WA is replete with mineralisation that hosts uranium and ‘critical minerals’ required for the global renewable energy sector. The state’s first uranium mine is under development, and high levels of activity are occurring in the state’s nascent critical minerals sector, with 168 WA-based companies pursuing rare earth-bearing minerals, 51 of which are actively drilling on their tenements. WA’s mineral deposits typically contain levels of the naturally occurring radionuclides (NORs) thorium-232 and uranium-238 that are elevated above the global crustal average. Workers are exposed to NORs during the mining and mineral extraction processes, and radiation doses that exceed applicable exposure standards may eventuate. The research traces the history of worker radiation doses from 1977 to 2020, finding the maximum dose was 163.4 mSv, more than eight times the current derived annual dose limit. Whilst 93.5 per cent of all workers received doses of less than 5.0 mSv per annum, the potential for elevated doses is ever-present as witnessed by 10.3 mSv reported in 2009/2010. The increase in activity coincides with a revision of the dose coefficients (DCs) associated with the intake of radionuclides. The research evaluates the revised DCs and forecasts doses from inhalation of radioactive dusts will nearly double, and lead to workers receiving doses exceeding 5 mSv for the first time since 2009/2010. The research finds that the current regulatory framework is fit-for-purpose. However, inter-agency relationships, and the capacity of the regulator to effectively regulate the current and future number of mining operations is questioned. The mining industry is vulnerable to capability and capacity constraints – but has failed to respond to issues in relation to competent radiation safety officers first raised by the Winn Inquiry (Winn, Mathews and Tough, 1984). Disconcertingly, monitoring of worker exposures to NORs reached a nadir in 2021, raising questions as to the veracity of worker doses reported to the regulatory agency. The research recommends personal dust sampling be prioritised.

Apr 16, 2024

By J B. Collier, R M. Fraser, O Dahl, I M. Platten

Grade control is a process of maximising value and reducing risk, through the delivery of quality tonnes to the mill via the accurate definition of ore and waste. It essentially comprises data collection, integration and interpretation; local resource estimation; stope design; supervision of mining and stockpile management. The foundation of all grade control programs should be that of geological understanding led by high-quality mapping and sampling to drive appropriate estimation strategies and mining. Gold veins show various complex features relating to erratic grade distribution (nugget effect), variable geometry and internal architecture. These include variations in dip, strike and width, late-stage faulting/shearing effects and geometallurgy. Such variations generally require close geological understanding to ensure optimum grade, minimal dilution and maximum mining recovery. A well designed grade control program will prove to management and stakeholders that by applying geological knowledge, the mining process can be more efficient and cost effective. This paper reviews the issues of grade control in underground gold mines and focuses on integrated mapping and sampling through three case studies.

Jan 1, 2009

By G Bubner, C Gaughan

Magnetite mineralisation within the South Middleback Range has been known since the early 1930s; however, it was not until 1989 that BHP (then owners of the Middleback Ranges mining leases) drilled 10 700 m of diamond core into what was then known as the Iron Duchess low-grade deposit. In 2002 a review of Iron Resources left in the Middleback Ranges and the identification of downstream processing benefits using magnetite as a primary feed source led to the commencement of an 18 000 m resource drilling program of the high-grade core of the Iron Duchess low-grade orebody (renamed the Iron Magnet deposit). This paper describes the geology, processes and procedures used since drilling recommenced in early 2003. The Iron Magnet deposit is located 53 km southwest of Whyalla in the South Middleback Range, South Australia. It is a Paleoproterozoic stratabound magnetite deposit that lies down-dip and lateral to the Iron Duke hematite deposit, hosted within the Lower Middleback Iron Formation of the Hutchison Group meta-sediments within the Cleve subdomain of the Gawler Craton. Magnetite bearing host units within the Lower Middleback Iron Formation can be divided into a æmixedÆ basal sequence, a lower iron carbonate unit, a middle iron talc unit and an upper iron silica unit, all units grading up sequence and laterally into one another. The magnetite mineralisation is hydrothermal in origin. The strongest consistent mineralisation coincides with the iron carbonate unit, and the hematite orebodies of the Iron Duke are interpreted to represent up-dip supergene enrichment of the same unit. The Iron Magnet occurs within a large-scale parasitic syncline-anticline pair on the west limb of a larger syncline. Major bounding north-south shear zones occur on the east and west sides of the deposit. Cross-cutting west-northwest, northwest, northeast and east-northeast trending faults displace mineralisation. The commencement of drilling in 2003 lead to the migration of geological and geochemical databases, re-logging and re-assaying of all old cores that intersected the deposit, updating of logging codes and procedures, and strict Qa/Qc procedures to ensure the study satisfied JORC standards. External consultants were used for auditing and bench marking. The strong geophysical responses of magnetite and the wealth of close spaced ground magnetic and gravity data already completed over the Middleback Ranges allowed for refining of drill hole targets for the drilling program. It also provided an indirect method for ascertaining magnetite grade and tonnage volumes.

Jan 1, 2005

By M Z. Abzalov

Drilling mineral sand deposits has specific challenges, which are different from drilling hard rock deposits: Drilled sequences are represented by non-consolidated free-flowing sands to semi-consolidated clayey sands and indurated layers. Valuable heavy minerals (ilmenite, rutile, zircon, leucoxene) have an average density of 4.6 g/cm3, which is significantly heavier than the hosting sand matrix; mainly represented by quartz (density = 2.6 g/cm3). The large difference in the mineral densities can result in sample segregation in the drilling rods and capturing devices causing biased composition of the recovered samples. The drilled strata can contain beds of consolidated sediments, hard pan lenses and concretions. Therefore, chosen drilling equipment should be flexible and permit a switch from drilling the free-flowing sands to hard rock drilling. Thickness of the sand hosted mineralisation varies from several metres to more than 170 m. Mineralisation is distributed above and below the water table. Evaluation of the mineral sands deposits is based on hundreds of drill holes and many thousands of samples, therefore drilling methods should be fast and cost effective. The drilling methods commonly used for mineral sand deposit evaluation, include aircore, triple tube diamond and sonic; including its variants, such as vibrocore drilling technique. The ability of the studied drilling techniques to properly address the above listed challenges in mineral sand deposits, whilst maximising the quality of the obtained samples has been compared in three deposits: Corridor Sands (Mozambique), Richards Bay (Republic of South Africa) and Fort-Dauphin (Madagascar).This study has shown that aircore samples tend to be negatively grade biased, underestimating the heavy minerals content, in particular when drilled intervals are located below the water table. Triple tube diamond core method can produce non-biased samples. However, results can be marred by incorrectly chosen drilling mud. Sonic drilling is a relatively new technique based on a high frequency vibratory technology. It is the only production drilling technique that allows a continuous relatively undisturbed sample of unlithified sands to be obtained. The main limitations of this technology preventing its wider use for developing mineral sand resources are the relatively high drilling costs, in particular when the depth of drilling exceeds 100 m, and speed of drilling advance.

Oct 5, 2011

By E Nik, A Manzoori, H Namavari, P Witt

The smelter building at Sarcheshmeh Copper Complex, Iran, houses two reverberatory furnaces and five Pierce-Smith converters. Under normal operating conditions SO2 emissions fill the building, posing a major health problem for all workers in the building, and reducing their ability to maintain the plant. The converter fume extraction system was analysed using plant measurements, engineering modelling of the entire system and CFD modelling of the extraction hoods. By applying fundamental engineering concepts, a user-interactive computer program was developed that enabled plant engineers and operators to gain a detailed understanding of the system. In conjunction with plant measurements, the model quantified the amount of inleakage throughout the system, identifying it as a significant contributor to the poor extraction performance. Furthermore, it enabled investigation of the effects of hood gates, converters on line, hood dampers, flue insulation, electrostatic precipitator (ESP) operation, and inclusion of an acid plant. The model gave unprecedented insight into the operation of a counterintuitive buoyancy-driven extraction system.

Jan 1, 2004

By T Angerer, N H. Maund, S Hagemann, D R. Cowan

Cliffs Natural Resources Pty Ltd - Asia Pacific Iron Ore's (formerly Portman Iron Ore Limited) K deposit (Dowd's Hill), at its Koolyanobbing operation in Western Australia, hosts enriched magnetite mineralisation below the presently mined haematite-goethite ore zone. Two distinct northwest-southeast elongated, highly magnetic anomalous bodies that dip to the north-east appear to be sourced by this deeper mineralisation. Magnetic modelling indicates significant remanent magnetisation with Qratios around 1.5, directed shallow down. The north-west anomaly is overlain by a ridge of uneconomic banded iron formation (BIF) and the present waste dump, whereas the south-east body was partly exposed during ongoing mining of overlying haematite-goethite ore. Sections of the magnetite mineralisation in this south-east anomaly were intersected previously by diamond drill holes. Review of the historic cores identified potential magnetite enrichment, with grades and mineralogy that might be amenable to beneficiation. A first-phase reverse circulation drilling program was designed to further delineate the trend and extent of the two anomalies. The following magnetite mineralisation assemblages are recognised from cores, reverse circulation (RC) drill cuttings and pit mapping of the south-east magnetic body: higher-grade magnetite-haematite ¦ goethite and magnetite ¦ pyrite and lower-grade, recrystallised magnetite-quartz (BIF), magnetite-carbonate, magnetite-talc and minor magnetite-bearing mafic schist. Disseminated specularite is locally present in theassemblages. Talc-schist and massive pyrite occur along the footwall contact. Magnetic susceptibility measured from drill chips within the magnetite-enriched zones reveals an apparent susceptibility values range of 0.2 to 1.3 SI. Preliminary results from Satmagan and Davis tube recovery analysis shows that the magnetite content in these mineralised zones correlate well with existing geophysical data and magnetic susceptibility measurements.

Jan 1, 2009

By J Jardine

An improved ground support method for development intersections, wide spans and stope brows was implemented at Kanmantoo mine. The method uses a jumbo to simultaneously drill and install self-drilling anchors (SDAs) to depths from 4.5 m to 7.0 m. Resin is subsequently pumped into each SDA using a specially designed integrated tool carrier basket, with plating occurring within 10 mins due to rapid resin cure. This methodology means that SDAs can be installed rapidly due to reduced process steps and wait times with reduced hazards to personnel. Cablebolts are used extensively in underground mines to reinforce the ground in wide spans, such as at intersections and stope brows. The flexible cablebolt tendon allows for a long, continuous and high-capacity reinforcing element to be inserted into the rock. A common cablebolt installation practice at Australian underground mines that do not utilise a mechanised cable bolter, is for cablebolt holes to be drilled by a jumbo or longhole rig, hand installation and grouting by a service crew, then plate tensioning following a grout curing wait time of typically 12 to 24 hours. This process involves multiple separate labour-intensive work processes and results in reduced availability of priority headings. This paper discusses the development history of vertical SDA use in wide spans at Kanmantoo mine. The installation process is fully described, including aspects such as reliable in-hole coupling of SDAs, resin selection and pumping aspects. A cost benefit assessment, and a case for ground stability are presented to compare cablebolt use to SDAs in development intersections.

Mar 29, 2023

By M Sebbag, T Taimre

Barrick Gold Corporation is proceeding with development of the Buzwagi Mine in the Lake Victoria Greenstone Belt District of Tanzania. The Buzwagi orebody occurs in the Nzega Shear zone within the Greenstone Belt and is hosted in a K-Feldspar rich granite in contact with mafic volcanic. The orebody presents 2.6 M ounces in 41 Mt of reserves, at 2.0 g/t. Over the ten year mine life, total material movement will be 261 Mt. The feasibility study was completed in 2006 and presented several technical challenges. Two principle challenges are grade control and the impact of dilution on the economic viability of the project. The principle challenges for grade control will be quality control and quality assurance in the sampling of the massive coarse grained granite, which comprises 70 per cent of the deposit. The principle challenge with dilution will be with the selective mining of the narrower mineralised zones contained within the mafic volcanics. This paper will focus on the mine planning methodology which has been applied including selective mine unit (SMU) and dilution estimation, net smelter revenue (NSR) calculation and the effects of cut-off grades to the project economics and mine schedule.

Jan 1, 2007

By S J. Schafrik, E S. Gilliland, E C. Jong, J Waynert, C W. Weiss

Two commercially available through-the-Earth (TTE) communications systems were evaluated at an active underground longwall mine in West Virginia. One system utilises magnetic field (H-field) antennae while the other system utilises electric field (E-field) antennae to achieve communication. A large portion of this mine is overlain by an inactive gas-oil field composed of densely spaced wells. This feature provided a unique opportunity to determine the impact of cased wells on both TTE technologies. The following communication modes were investigated: surface to underground, underground to surface, underground to underground and real-time two-way communications. Standard deployments of the TTE systems using the manufacturer’s recommended procedures were able to achieve clear communications between underground and surface locations under certain circumstances. As a result, the design and deployment that will optimise TTE transmissions are unique to each system and to the specific area of the mine. This field study was conducted as a part of a larger multisite evaluation of available TTE systems in an effort to determine their operational sensitivity. The performance of these two TTE systems suggested that one may be preferable over the other depending on the conditions present during deployment.CITATION:Jong, E C, Schafrik, S J, Gilliland, E S, Weiss, C W and Waynert, J, 2015. Pairing magnetic and e-field through-the-Earth communication systems based on mine site conditions, in Proceedings Third International Future Mining Conference, pp 245–252 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By M Haest

This study demonstrates the application of HyLogging™ technologies for mineralogical characterisation of different iron ore types throughout the Hamersley Province (Western Australia), including a channel iron deposit (Murchison Metals Ltd) and bedded iron deposits in the Brockman and Marra Mamba Iron Formations (BHP Billiton Ltd).Drill core from these deposits was analysed using CSIRO’s hyperspectral drill core logging systems (HyLogging systems), which are commercially available at the AMDEL and AMMTEC laboratories in Perth (Western Australia), through a leasing agreement. These HyLogging systems provide high resolution photographs at 0.1 mm pixel resolution as well as visible and infrared spectroscopic refl ectance data at 1 cm spatial resolution. The minerals identified include haematite, goethite and its subtypes (ie vitreous and ochreous goethite), AlOH-clays (kaolinite, Al-smectite and white mica), carbonates, gibbsite, chlorite, amphibole and hydrated silica as well as water content. The abundance and composition of these minerals was established from the spectral data and was validated against XRF analyses.The full potential of HyLogging systems in the iron ore industry is only starting to be unveiled, but some major benefits have already been demonstrated:• HyLogging systems can delineate different ore zones by mapping the vitreous and ochreous goethites. This has a potentially large impact in mine planning and operations, as hard, vitreous goethite and soft, powdery, ochreous goethite have different processing characteristics that can affect plant throughput if not carefully managed.• HyLogging mineralogy can also be used to support stratigraphic interpretations of the host, for example in subdividing the Dales Gorge 1 - 4 submembers of the Brockman Iron Formation.• HyLogging can have a potentially signifi cant impact on waste rock characterisation, as many of the waste materials can be identifi ed and quantifi ed with hyperspectral data (eg clay-type,• hydration state).• HyLogging can provide accurate three-dimensional (3D) mineralogy to iron ore companies that will empower them to improve future exploration and resource planning.• Application of high resolution photography to further improve ore deposit domaining is also to be considered.

Jul 11, 2011

By R M. Arellano, D M. W Harney, M Makhuvha

Mineral resource and ore reserve estimates are founded on two sources of data: tonnage and grade. The tonnage is a product of volume and density; both of which are estimates. Density impacts numerous operational factors, which include, but are not limited to, mine design, mine planning, equipment selection and operational performance. Hence, density is a significant parameter and its determination requires similar care as the measurement of grade. Selecting an appropriate method to determine density, and ensuring its rigorous application, thus reduces risk and can improve operational performance, which in turn increases profit margin.Different Anglo American sites use a variety of practices and protocols to determine density, which is highly dependent on the physical characteristics of the orebody, local conditions and historical practices. Also, individual sites sometimes execute the same method in a slightly different way, which may also affect the outcome of the measurements. In order to gain a better understanding of how density is determined at Anglo American projects and operations, a review of these techniques was undertaken. The objective of the study was to identify and share good practices across the company, as well as to look for improvement opportunities, where applicable. Ten different methods of measuring density, applied to nine different commodities, were identified and described. An additional technique was recently developed by Anglo American Technical Solutions. The core pycnometer is a large gas displacement pycnometer capable of measuring density at high accuracy on full pieces of intact core.This paper provides an overview of methods used to determine density within the Anglo American Group, including quality control and quality assurance aspects. It is not the purpose of this paper to identify a preferred method, but to highlight the importance of choosing the best suited practice for a project or mine site. In addition, a case study comparing two different density determination methods applied to the same rock samples from the Los Bronces Copper mine was undertaken and the results of that study are presented here.Selecting the most appropriate method to determine density and comparing results from two or more techniques against each other, together with other suitable quality control procedures, is considered to be of utmost importance for all mining operations and exploration projects.CITATION:Makhuvha, M, Arellano, R M and Harney, D M W, 2014. Determination of bulk density in Anglo American plc, methods and impacts, with a case study from Los Bronces Mine, in Proceedings Ninth International Mining Geology Conference 2014 , pp 85–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By D Kent, R Paine

"Automated mining systems are increasingly being seen as a key requirement for a productive mining operation in the future. The importance of an integrated communication network infrastructure to support such systems is growing.This paper outlines the introduction of automated mining systems in large conventional mines as well as their growing role in block cave mines currently operating or being developed. The paper will then focus on a case study of how the communication infrastructure is fundamental to the operation of such systems and explain why the resultant communication networks require much more than just increased bandwidth (data capacity) to properly support the automation system within the overall mine operation.Mining operations already embarking down this road are discovering that the required network must be based on a true enterprise level architecture to not only enable the mine’s current plans for remote and automated mining, but also provide a scalable and integrated platform for future developments and requirements. The emerging issues for the communication network to truly support automation systems include: increased complexities of operating and maintaining multiple networks integration issues with disparate systems problems with reporting particularly as demands for corporate reporting and compatibility with enterprise systems become the norm ongoing management challenges, which will only increase with the proliferation of new technologies.The paper will explore how certain mining operations are addressing this by adopting a long-term strategy for automation deployment, which includes laying the necessary foundation architecture to meet their current requirements, while supporting their future visions for the fully automated mine.CITATION:Paine, R and Kent, D, 2014. Developing the foundation communication infrastructure to support remote and automated mining initiatives in underground mines, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 151–158 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By E Jak, P Hayes, J Chen, M Shevchenko, E Nekhoroshev, D Shishin

Recent decades have seen significant advancements in analytical and experimental techniques, thermodynamic theory, and computational capabilities in high temperature research which are particularly timely to address the challenges of increasingly complex and variable feedstocks in both primary and secondary pyrometallurgical processes, the need to optimise and improve them. Currently a research program is in progress on the development of the 20-component multi-phase thermodynamic database for pyrometallurgical smelting, refining and recycling systems describing thermodynamics and phase equilibria of molten slag, matte, speiss, salts, alloys and associated solids. The integrated experimental and modelling program has been supported for nearly two decades by several consortia of 14 major international companies with over 30 operations around the world, integrates many components, incorporates many in-house developments, and brings together many different groups of professionals of different levels from junior and mid-career to senior from both industry and university sectors. The aims of the paper are:  to outline the many components and issues of the overall program including analytical, experimental and thermodynamic modelling research as well as implementation of the results in industrial practice, professional education, planning and organisation issues.  to highlight the opportunities, challenges, and possible solutions.  to present these to all different groups of professionals involved in the current program.  and thus, importantly, to facilitate possible future further developments and collaborations in the field of phase equilibria and thermodynamics of complex high-temperature systems.

Jun 19, 2024

By García B., Wolff E.

In Colombia, northeast of Antioquia, there is a gold deposit that has produced continuously since the middle of the XIX century, located within mining title RPP-140, property of Gran Colombia Gold Segovia (GCGS) since 2010. Mining materials are taken to the “María Dama” Processing Plant where 1500 tonnes of materials are processed daily. Before 2010, the previous owner of the mining title processed about 600 tpd and directly discharged almost all tailings, given that they had no capacity to put them into final deposits. El Chocho was conceived as a final tailings deposit to store the pulp produced by the processing plant; it was divided into two phases with two dams (upper dam and lower dam) given that the presence of illegal miners at the lower phase impeded a single dam design. A squatter impeded construction of the upper dam; so afterwards, starting at the higher end was necessary (owned by GCGS), building dam 1B to store tailings in pulp; after the squatter returned the lands to the owner (GCGS), construction of tailings dam 1A was required and thus complete construction of dam 1C or the upper dam. While all of this was happening, GCGS decided to acquire a 1500 tpd filter press which currently dehydrates tailings in order to take them to the valley controlled by dam 1A. Construction of dam 1A was designed following the containment wall model, made with geotextile tubes. These improvements generated reduced pressure on renewable natural resources because water is recirculated and less fresh water contributions are required; less pressure is placed on soil, flora and fauna because the area intervened for tailings storage will have a higher storage capacity and, as such, a longer useful life.

Jun 17, 2024

By J Ledgerwood

Namakwa Sands is a mineral processing company based on the West Coast of South Africa and is solely owned by Exxaro Resources Limited. Mineral ore is mined and processed, concentrated and both chemical and mechanically upgraded before being sent for electrostatic and magnetic separation units. The final high value mineral products report as Zircon, Rutile and Ilmenite.The recovery of non-magnetic material is largely dependent upon a number of factors, including but not limited to dew point, ambient temperature, feed rate, mineral size distribution, specific gravity and mineral content in head feed. One important limiting factor to recovery in typical dry mill operations is the particle size distribution of the feed. Variance in the particle size has catastrophic consequences for recovery. This is the reason for this study. Until recently large variances in non-magnetic production were viewed to be a function of machine operation. This view was later rejected with the feed size distribution determined as the major driver of low recoveries, for Namakwa Sands orebody 50 per cent variance in particle size distribution can be noticed within one day. This is because of the successive mining blending techniques employed.The predicament is that the two modes were so closely placed together that recovery of a single mode is almost impossible without the consequence of greatly reducing recovery. The second mode was found at 125 µm while the first was at 90 µm. Interestingly, for the mentioned feed type a cumulative size distribution of a unimodal feed type is almost exactly the same as for a bimodal size distribution. Thus a plot of cumulative size distribution will show no difference due to the modes being so close together. This is the reason why this phenomenon was not noticed before.The study also found that, using an high tension roll (HTR) or rare earth roll, a fine stream with a single mode at 90 µm versus a coarse stream with a single mode at 150 µm would yield completely different results interms of yields. Larger conductive particles are thrown from the roll while small particles loose charge faster (entrainment). Results in terms of the bimodal size distribution show that even though 25 per cent of the feed type is greater than 150 µm the yields followed a similar pattern to that of the coarse particles rather than that of the majority (75 per cent) fine particles. This confirms what was published by M Ziemski and P N Holtham in 2005 on charge decay rates; they mentioned that particle bed effects played a major role in recovery.

Oct 5, 2011

By Waghorne E. P

The State Electricity Commission of Victoria is Australia's largest single coal producer. Approximately 19 Mt of coal will be produced in 1989 from the SEC V's newest mine, Loy Yang Open Cut (LYOC), which com- menced overburden stripping operation in October 1982. When the adja- cent Loy Yang Power Station is completed in the late 1990's, LYOC will supply between 35 to 45 Mt/a, depending on power station performance and demand of coal for non-power generation uses. LYOC has been a major challenge for the SECV. It is the biggest single open pit coal mining development undertaken in Australia, with a whole of life capital cost approaching A$1 billion. The mine has supplied a very rapidly growing demand for coal from the expanding power station while developing in breadth, length and depth. Coal demand has consistently been above the figures anticipated during the initial planning because of the substantially improved performance of the 500 MW units of the Loy Yang A Power Station. The superior performance of the LYOC and power station has generated additional electrical energy during the first 5 years of power station operation compared with the initial planning targets- at almost no additional capital cost. This has been a major benefit to the SECV. LYOC will continue to present major challenges for the SECV, particularly in achieving overburden removal and coal reserve targets as development of the open cut continues to full depth over the next 15 years.

Jan 1, 1989

By E Rubio, N Morales

A common practice in the mining industry is to decompose the planning process into different tasks, so the overall process and specific schedules can be constructed easily. Nevertheless, currently there are some adverse effects, such as not capturing the real value of a project by not taking into account the construction of several underground drifts and general infrastructure. Then the common practice is to compute mining sequence and cut-off grade profiles over the life of the mine without constitutively integrating the development schedule as a means to measure the constructability of a given mine design and sequence. Thus, the investigation summarised in this paper shows a novel, integrative way of treating an underground mine sequence and production schedule while considering drift development scheduling. Moreover, it is thought that, because of this original model, the whole underground production scheduling exercise must concentrate on combining the development and the production scheduling to compute a robust and a feasible production schedule.In order to quantify the effect of the conventional way of viewing the planning, the concept of the building information model (BIM) needs to be used, which was postulated by Charles Eastman and has been used extensively since the late 1970s. BIM takes other aspects of a project into account, considering at the same time the spatial relationships, quantities and properties of building components, but especially some kind of model visualisation, which is the advantage to be incorporated. This paper presents the basis for an optimisation model that allows for defining the sequence of the mining development so that the production plan can be achieved. For this, the model considers the space dimensions, time, pattern or strategy, cost or benefit, precedence and resources available. Tests were performed considering a block caving and sublevel open stoping method. Finally these tests showed the main conclusion, that production sequence changes when the building capacity is considered.

Sep 26, 2011

By P Minkkinen, J Lohilahti, T Korpela, B McPherson

Concentrator plants intake the ore from the mine and produce concentrates by extracting valuable minerals in a succession of process steps. Controlling the extraction process and detecting changes in the process requires updated information on a minute basis. Moreover, due to economical reasons, one must also collect metallurgical samples on a daily basis for monthly reporting.In this paper, we present how slurry samplers were installed in a Cu-Ni flotation plant to accomplish the aforementioned tasks. An on-stream elemental analyser at the plant is used for flotation process control by taking samples from selected process streams. Two process streams, the flotation feed and tail, are also equipped with metallurgical samplers. The metallurgical samplers were designed to have low head loss, be robust and easy to maintain and to collect slurry samples in a reliable way for the metallurgical accounting.Samples were collected by different sampler types and we discuss the uncertainty arising from sampling in the assays. Variographic analysis was carried out on the process data in order to find periodic components in the process, and estimate the correct number of shift sample increments and measurement error components. The metallurgical samplers were proven to be reliable devices with zero downtime and no sanding issues in the main process flows. In addition, we show that the tail measurement is the most important one for the plant recovery calculation, which emphasises the importance of the sampling accuracy in the tail stream.CITATION:Lohilahti, J, Korpela, T, Minkkinen, P and McPherson, B, 2014. Analysis of slurry sampling arrangements at a froth flotation plant, in Proceedings Sampling 2014 , pp 91–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By R Morrison, R Dunn

In many mineral processing operations, the reported production figures for an accounting period may not make the best use of available data. While most of the mathematical approaches, such as check-in/check-out, mass balancing, used in effective metallurgical accounting strategies are well understood, the sources and magnitude of measurement errors generally are not. As part of the æAMIRA P754-Metal Accounting and ReconciliationÆ project, a study was undertaken at the Northparkes copper/gold concentrator near Parkes, New South Wales to examine the data used in their concentrator metallurgical accounting system. This paper summarises the results of a detailed examination of the mass measurement systems around the concentrator as well as the primary sampling system used for grade estimation. The goal of this work was to develop practical techniques to quantify the error (ie both accuracy and precision) of the measured metal accounting information. With this information, statistical confidence levels for this data can then be calculated. If the errors are small, the effect of error in each piece of measured data can then be propagated to other calculated production figures such as recovery and feed grade using a statistical technique called æthe propagation of errorÆ.

Jan 1, 2007