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By F Burns, G Peachey

The Hidden Valley process plant has recently undertaken a program to relieve process flow bottlenecks and improve process automation. An environment of cost reduction and restrained capital necessitated solutions that primarily utilised existing equipment and internal resources. Removing bottlenecks relieved pressure from a strained circuit that was unable to maintain consistent performance. Improved process automation firstly stabilised the process, then allowed the circuit to sustainably operate at the expanded capacity limits. These allowed implementation of an operating approach that focused process operators towards identifying and resolving process disturbances in advance. Plant recovery and throughput have markedly improved as a result.CITATION:Burns, F and Peachey, G, 2014. Recent process improvements at Hidden Valley gold mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By J Wei, A Yo, R Levy

Waste water reuse from municipal and industrial effluents is becoming increasingly important in many areas around the world. Water scarcity, local regulation and environmental impact are driving many industries like coal and copper mines to reuse the large volume of waste water they produce. For example, the Chinese coal industry generated about 4.2 billion tons of mine waste water in 2005 of which only approximately 30 per cent was reused. Coal energy represents 76.6 per cent of the total energy generated in China in 2007 and most of the coal-fired power plants are located in north-west of China, which is a water stressed area.The selection of mine waste water treatment process is challenging as the effluents typically contains high levels of organic compounds and salinity and their composition can vary significantly. In recent years there has been a growing interest in the integration of ultrafiltration (UF) and reverse osmosis (RO) membrane technologies for mine waste water treatment and reuse.In this paper, an overview of the design and performance of ultrafiltration and RO membranes applied for reuse of mine waste water are discussed. A study was carried out in two effluents treatment plants treating copper and coal mine waste water, which are located in Chile and China respectively. The following topics will be discussed to demonstrate the performance of an integrated membrane system in mine waste water reuse: The main challenges from copper mine waste water treatment: high level of chemical oxygen demand (COD); high level of total suspended solids (TSS); high salinity; high concentration of silica, sulfate, iron and other contaminants; and fluctuation of raw water quality. The main challenges from coal mine waste water treatment: high level of total dissolved solids, and waste water quality fluctuation. Design parameters for waste water treatment systems: Selection of pretreatment for dual-membrane system in the copper mine: Clarifier with coagulation and flocculation to remove high TSS; Dissolved Air Flotation (DAF) to remove non-settling solids; Media filtration to handle fine solids and particulate organics; Activated Carbon filters (ACF) to remove dissolved organics, colour and odours. Selection of UF and RO membranes and specific design of their recovery, flux, chemical dosage and cleaning regimes. Finally, the performance of UF and RO, including the main fouling factors and efficient cleaning procedures, will be presented and compared to the design parameters to demonstrate the efficiency and performance of the selected integrated membrane systems in each case.

Jan 1, 2009

By R Shrimali, P Rajmeny, L Shekhawat, A Joshi

Rampura Agucha open pit mine has successfully been excavated to a depth of 320 m, incorporating multistage working. The key to success is the implementation of presplitting as control blast measures at every stage of mining, including intermediate cut backs, in addition to the final wall. The major challenges encountered in establishing presplitting in the hang wall as compared to the footwall of the mine are:reversely dipping foliation, ie dipping into the hang wall itselfstriking obliquely at an angle of 20–30° with regards to the general strike of the pit wallthe presence of numerous geological planes of weaknesses like major faults, slips, etc.Control blast parameters like hole inclination, spacing and stand-off with buffer row were chosen initially from the literature survey and were subsequently fine-tuned by field trials to the mine geo-mining conditions of the hang wall. Electronic initiation used for trim blasts along with double presplitting in fault-affected zones helped in getting better presplit performance and resultant stability of the hang wall.CITATION:Rajmeny, P, Shrimali, R, Shekhawat, L and Joshi, A, 2015. Establishing the design parameters of a control blast for long-term stability of the hang wall at Rampura Agucha Mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 437–446 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By A Roseman, T Gruber

Traditional methods for installing gaskets for segmented bored tunnels have relied upon different bonding procedures with adhesives that carry a series of disadvantages to segment producers. Fixation of the gaskets into the concrete segment as part of the casting procedure has been developed over the last 20 years and has emerged as an economical solution to produce high-quality tunnel segments for various technical tunnel applications. This paper investigates the advantages of using anchored gaskets, the different tunnel systems that employ anchor gaskets and reviews the first anchor gasket project; the Lee Tunnel and analyses how segment production efficiencies are gained.CITATION:Gruber, T and Roseman, A, 2014. Use of anchored gaskets in segmented bored tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 253–256 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

GENTLEMEN, lt is with much pleasure I meet you tonight at this the second meeting of the Australasian Institute of Mining Engineers, held in Western Australia, and I sincerely thank you for the honour you have conferred upon me in electing me as your President. I greatly appreciate the distinction, and will endeavour to fulfil the duties of the office to the best of my ability, and hope to prove a worthy successor to those gentlemen who have held the position before me. On behalf of the local members of the Institute, I extend a hearty welcome to the members from the other States of the Commonwealth, who have come so far to attend this meeting, and also to the non-members whom we have invited this evening. We are especially pleased to have Mr. Gregory, our Minister of Mines and Railways, and the Government and School of Mines officials with us; and I take this opportunity to thank the Premier, Mr. Gregory, and the Government officials for the assistance given us, and for doing so much to make the visit of our members from the other States so pleasant and instructive. I have also to thank the Mayor and Councillors of Kalgoorlie for the courtesy and hospitality given to our members, which is much appreciated.I assume you want me to follow the time-honoured custom of giving a Presidential address...

Jan 1, 1909

By D Laurence

Mining cycles have come and gone and with them there have been dramatic swings in the levels of interest and student entry into minerals-related education programs, hence graduate supply to the industry. So what is the problem? These trends will keep happening and the industry will keep on keeping on – or will it?This paper discusses recent trends in Australian minerals education programs and some international examples, together with some of the more recent initiatives taken by both the minerals education sector and the industry, such as the Minerals Tertiary Education Council (MTEC) and MEA. The real problem is that things will not just keep going the way they have over recent decades – there will come a time when there is no longer a supply of minerals academics available to provide the educational programs; and universities will simply shut down subcritical mass mining programs and invest in the much more lucrative programs such as commerce, law, medicine, etc. By the time this starts to happen it will be at least ten years too late for any last-minute reactive response by industry, if they were to try and avert such a consequence. International experience with mining programs bears out this scenario quite clearly.It is therefore timely for industry individual mines and mine management to take a much more strategic look at their role in the education sector. Sustainable mining also means sustainable minerals education – without one, the other will not function over the long-term. There is a pressing need for long-term strategic buy-in by industry into the education sector – not just for the good times, but also through the tough times. This means much more than a scholarship here or there, but includes such commitments as major industry-university research partnerships; collaborative recruitment initiatives and much more. The paper will discuss a range of such issues, problems and opportunities to address these important issues through strategic, comprehensive, long-term commitments by industry and equally significant and appropriate responses by the education sector. We care – do you?

Mar 21, 2011

By K L. Silversides

Shales form distinctive peaks in natural gamma downhole logs, which are used to manually identify the location of ore boundaries. These shales form important lithology markers that can potentially be automatically identified using Gaussian processes. This approach is trialled using data from a typical iron ore mine in Western Australia which contains the Marra Mamba sequence of the Hamersley province.The method uses Gaussian processes (GPs) with a single length scale squared exponential covariance function. A library of 8 m sections, where natural gamma measurements were taken at 10 cm intervals down the hole, was used to train the GP model. This library was iteratively improved and was tested using natural gamma logs that were not included in the library. Areas that were misclassified or were not clearly classifi ed were added to the library. The new library was then used to train the model and improve the results. The trials used a double gamma peak from the NS3 and NS4 shales at the boundary between the Newman 1 and Newman 2 ore zonesin the Newman member and the AS1 and AS2 shales at the base of the West Angelas member. The results show that both boundaries can be identifi ed with an accuracy of over 99 per cent. The classification has the highest accuracy on undeformed shales. This method provides a fast, accurate and objective identifi cation of shale and ore boundaries and can potentially replace the current manual detection.

Jul 11, 2011

By M Haest, S Sandler, R Botha, H Lang, K Hume

Benchmark practices in the mining industry include the establishment of Quality Programs — Quality Assurance and Quality Control (QAQC) — to monitor the correct execution of sampling protocols and control each stage of the ‘Sample Cycle’: Sample Collection, Preparation (comminution) and Analysis. QAQC reports commonly include statistical-numerical results that quantify performance of QAQC controls (field duplicates, preparation duplicates, blanks, standards etc). Graphics such as scatter plots, QQ plots, histograms and cumulative frequencies are used to represent the results. Statistical values including relative difference, absolute difference, relative variance, averages, T-test, and Zscores are used to quantitatively express the relationship between duplicate pairs ... but is an effective quality program just a statistical exercise? This paper aims to highlight the concept of ‘Quality Management’ (QM) as the precursor of continuous monitoring (ideally in real time) of QAQC results on Exploration, Production, Processing and Port samples, determined by trend analysis performed on a time and/or grades basis. Currently, there is a paradigm in the process of quality assurance that if individual data points fall within a predetermined acceptance limit then they are ‘acceptable’ and therefore suitable for informing operational and investment decisions. However, what is stated with respect to QM is that sometimes results found within the acceptance limits can indeed be internally biased, or show material deviations over a period of time, thereby impacting reconciliation results and/or potentially creating discrepancies with the final buyers. QM refers to the proactive detection of these ‘anomalous tendencies’, the approach and communication with the source of the information, the understanding of the reasons that cause the deficiencies, and the generation of agreed action plans to remediate the situation and ensure the consistency of results, in other words: continuous improvement on proactive manners.

Mar 22, 2022

By G Baiden

The removal of rock blockages in mining operations has long been a risky undertaking, especially in high overhead conditions. Moreover, the assessment of where to put charges and the placement of them has been difficult due to the lack of visibility and safe access to the area. Traditionally, wedging long poles with explosives on them to keep the operator at a relatively safe distance has been the tried and true method of attempting to remove the blockages. Unfortunately, this is not a perfect system as it usually takes several attempts to remove the blockage. Each successive attempt results in even more dangerous conditions for workers and/or damage to the mine due to the successively larger amounts of explosives used until the hang-up finally comes down.Over the years, different ideas have been proposed to improve this process and reduce the inherent safety risks. Some of the technologies that have been trialled include projectiles fired at the hang-up; large, cumbersome arms; and massive amounts of explosives, each of which come with their own inherent safety risks that result in dangerous situations for miners and the mine.After gaining a thorough understanding of the process, Penguin Automated Systems Inc has developed a robotic system that is capable of working in a rock blockage safely. The idea combines the latest in telerobotics technology with 3D scanning and underground geospatial positioning. The hang-up removal is performed by scanning the inside of the hang-up to rapidly develop a geospatially placed 3D model for the operator to use. The 3D model is detailed enough that the operator can attempt to pick the ‘keystone’. A blasting engineer or the operator can then determine the exact position where the explosive charge should be placed in the 3D model and thus at the actual hang-up. The operator, controlling the robotic arm, uses the 3D virtual reality model of the robot system and the actual drawpoint information model to display the location information, the arm can then reach into the hang-up to position the charge using the kinematic model of the robot system. The 3D model is used to provide views inside the hang-up so that the operator can move the arm safely and precisely. This process allows the operator to place the charge (using the 3D representation of the drawpoint) from a long distance away. As the process continues, the end of the arm drills the rock and precisely loads the explosives. The robot then returns the blasting cable to the command station, which is located in a truck at a safe distance from the blockage.This paper will review the development of the system and present the results to date.CITATION:Baiden, G, 2016. Robotic hang-up assessment and removal of rock blockages in mining operations using virtual reality for safety, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 745–754 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By G J. Lyman, S A. Tittlemier

International regulations exist to manage the concentrations of mycotoxins such as Ochratoxin A (OTA) and deoxynivalenol (DON) in grains and prevent health risks from excessive exposure to OTA and DON. Since the permitted levels of these mycotoxins are very low (existing maximum levels are in the range of 5 ppb for OTA and 1–2 ppm for DON), sampling for these mycotoxins is potentially challenging. Given that the distribution of infected kernels in a consignment of wheat can be highly heterogeneous, detection by current sampling methods is subject to a high variance. Furthermore, the concentrations of mycotoxins in individual kernels vary over orders of magnitude, intensifying the heterogeneity of the bulk grain.In these circumstances, there is much interest in developing sampling plans that inform regulatory agencies, and mitigate the risk of misclassifying grain shipments as compliant or non-compliant within the global grain trade, when correctly implemented.Experimental data from laboratory and field studies describing individual wheat kernel concentrations of OTA and DON were combined with experimental data describing the variance due to the analytical methods used for OTA and DON to calculate the sampling distribution for wheat having various levels of contamination. This work has focused on quantifying the heterogeneity of samples at the point of submission for analysis and within subsequent sample preparation to arrive at total sampling distributions that include uncertainties due to the intrinsic heterogeneity and the analytical uncertainties. The sampling uncertainty that relates to the difference between the primary sample analysis and the true lot analysis is not included as it has been dealt with elsewhere.CITATION:Lyman, G J and Tittlemier, S A, 2017. The sampling characteristics of grains contaminated by mycotoxins, in Proceedings Eighth World Conference on Sampling and Blending , pp 281–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By A R. Hollis, M Heddon

The safe life cycle of a Tailings Storage Facility (TSF) is founded on the fundamentals of proper design, construction, operation and closure. Leinster Nickel Operations (Leinster) utilises four active TSF cells that are cycled between filling (deposition), desiccation, and construction to meet a targeted rate of rise. This results in ongoing and consistent raising of the TSF walls. Critical to maintaining the safe life cycle through this consistent wall raising is precision construction and high frequency quality assurance to ensure compliance to design requirements and TSF walls free from defects. Leinster has recently deployed Intelligent Machine Control technology for TSF construction. Advances in Intelligent Machine Control have decreased variability in construction; ensuring variations are within the tolerances of design. The Intelligent Machine Controls are programed to ensure construction conforms to design tolerances of +/-30mm. This level of accuracy provides assurance of borrow area set out, compacted layers are as per design, compaction monitoring is within the zone placed, scarification between layers to prevent lamination is maintained, and batter angles are set to the correct grade. This level of control provides certainty that construction meets the design intent. In conjunction with Intelligent Machine Control, periodic drone surveys are conducted to verify construction against design. Advancement in survey equipment and techniques allow higher frequency, high accuracy survey to be completed on demand by site based personnel. This provides quality assurance through all stages of the construction phases, as well as the final constructed wall, ensuring compliance to design. Combining Intelligent Machine Control with higher frequency quality assurance provides an increased level of certainty that the TSF construction is defect free and within quality specifications. These recent technological advancements in Construction and Quality Assurance ensure cell raises are constructed to the design intent with greater levels of accuracy and precision than ever before.

Jul 1, 2021

Igneous phosphate deposits located in tropical and subtropical regions of the world are characterised by low P2O5 grades, very diversified mineralogy and intensive lateral plus vertical variations in chemical composition, mineralogical assembly, rock texture, grain size, slimes content and morphology plus surface coating of apatite particles. Those variations characterise ore types with distinct behaviour in mineral processing plants. This work reviews the main challenges to concentrate those ores, addressing developed solutions. Apatite concentration requires long chain anionic collectors to conduct reverse flotation of barite (alkyl sulfate) before direct flotation of apatite (sarcosinate, sulfosuccinate and oleate) at basic medium. The long chain collectors decrease the surface tension of the flotation solution (?LV) and a particular value of 51 mN/m was found to promote the most selective separation between apatite/gangue at a particular plant. Effective control of the magnitude of ?LV in industrial plants has not been realistic because there is a lack of reliable instruments to carry out in-situ measurements. Regarding gangue depression by starch, a review is made on possible mechanisms that promote its remarkable ability to depress some minerals (Fe-oxides, ortho plus meta silicates and calcite) vis-a-vis others (quartz, apatite and layered silicates). Flotation recovery (R) of fine (20<R<30 per cent) and coarse (30<R<60 per cent) apatite particles is considerably lower than the recovery of the intermediate ones (R>70 per cent) and inadequate hydrodynamic conditions within flotation cells are the main reasons for that behavior. Once the best hydrodynamic conditions to float coarse particles are not the same to float the fine ones, flotation of coarse and fine particles is commonly conducted at separated circuits in industrial scale. Entrainment of very fine gangue particles is an important source of contamination of apatite concentrates, mainly when weathered ores are treated. In most cases, adjustments in flotation equipment (columns or mechanical cells) promote considerable improvement in the quality of final concentrates.

Sep 13, 2010

Chalcopyrite concentrate was combusted in oxygen-nitrogen atmospheres, the composition of which ranged from 1-100 per cent oxygen. Factors studied included particle size, experimental temperature and oxygen concentration. The study was assisted by chemical and X-ray diffraction (XRD) analysis and temperature measurements of single particles. Size reduction occurring after melting was found to have a major effect on the overall reaction time. Thus time to attain ignition was largely determined by the original particle size, whereas combustion time was independent of this factor. For particles larger than 40 I'm in air the time to attain ignition predominated. The maximum temperatures measured for single particles were the result of pyrite present in the concentrate. Chalcopyrite did not attain thesame temperatures. Vaporization, either as CU(g) or CuO(g) lImited the temperature. Maximum temperatures measured for single particles of pyrite ranged from 1610°C in 14 per cent oxygen to 2360°C in 100 per cent oxygen (both at 700°C). Measured temperatures were compared with those calculated from a diffusion-based model.

Jan 1, 1983

By W Schauenburg

The increasing problems associated with the disposal of waste and the potential for use of by-products as underground filling material is a subject which is relevant not only to the coal-mining industry. The progressive scarcity of surface disposal facilities for by-products and waste has now become a problem in all sectors - not only for the mining industry. The considerable capacity offered by underground cavities which exists in various mining branches present an extremely promising potential in this context. The backfill process for coal mining developed by DMT in co-operation with Ruhrkohle AG make use of the cavities which are offered by the extraction of coal. It consists of several stages: The fine-grained by-products, such as sludge, filter cakes, fine refuse, ash and flue-gas cleaning residues are processed on the basis of specified formulations in metering, blending and pump facilities on the surface to produce pumpable pastes with precisely defined flow characteristics. On Walsum Colliery of Ruhrkohle AG up to 200 m3/h stowing paste is conveyed into the mine in pipes with diameter of 200 mm (8"). The delivery pressure of the pump operating on surface in conjunction with the hydrostatic pressure of the shaft pipe - amounting in total to as much as 25 MPa - makes it possible to convey the stowing material for a distance 12000 m underground up to the workings without any need for additional booster pumps. Via a pipe installed in the face, the paste is pressurised into the cavities in the specially fragmented rock in the mined-out zone well behind the support. Consistent use of stowage of caved-in goafs makes it possible to reduce surface settlement above the workings. Fires in the stowed rock are either smothered or completely prevented thanks to the exceptional air-tightness in the caved goaf and the cooling effects of the slurry stowage. The reduced danger of fire, the preventation of air-leakage and the positive effects on gas emission from the coal improve safety in the workings.

Jan 1, 1998

The complicated mining-geological conditions in the Kuzbass have led to some difficult mining situations in the past. Now, with historical data, supplemented by geomechanical information and measurements, together with an appropriate kinematic theory, a more reliable basis exists for prediction and control of the geomechanical state during extraction, with caving and with backfilling. Continued progress and improving reliability comes from data banks and computations, and now prediction of geomechanical situations is upgraded by more routing measurements and monitoring. Not only in the Kuzbass, but throughout the USSR, 14 dedicated groups are ready to solve various specific problems of prediction an control of geomechanic situations with assured increase in the quality of mining.

Jan 1, 1991

By A Woodley, G Keir

The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG emissions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects.This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a flexible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites.The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality).The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.CITATION:Keir, G and Woodley, A, 2013. Regional trade-offs between mine water and energy use - a water treatment case study, in Proceedings Water in Mining 2013 , pp 21-28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Evolutionary changes to the original sizer concept are mild when compared to those which have taken place in the engineering standards embodied in today's commercially available machines. This paper examines the principles of sizer operation and reviews the development trends in new applications for this unique screen type.

Jan 1, 1978

By J P. van Dyk

A new crude ilmenite beneficiation process was recently proposed that allowed for the preparation of a smelter grade ilmenite from ilmenite with elevated chromium content. Magnetising roasting was not utilised in the process. As part of this circuit an ilmenite low susceptible reject stream was produced that had a low magnetic susceptibility. In this article a magnetising roasting process was investigated to beneficiate this material. Tests were conducted on material produced by pilot scale simulations on a typical South African East Coast heavy mineral reserve. The results obtained were compared to those published in literature for crude ilmenite. The small-scale experiments were used to define approximate operational limits for the oxidising roasting of a low susceptible ilmenite low susceptible reject stream, although industrial roasting conditions may differ significantly from those obtained in laboratory units. In a next phase these results will be confirmed on pilot plant scale.

Jan 1, 2001

Aurum Reef Resources is a provincially owned unlisted public company which holds a number of prospecting licences over Otago hard rock historically active minesites. The Bullendale Licence 31 1845 was applied for in 1985, granted 1991, including a DoC special condition allowing re-opening of the historic workings. The underground workings were commenced in 1862 and up to the mine's closure in 1906 some 40 000 ounces were produced at an average grade of 15.5 g Au/t. The purpose of the summer 1991 work programme was to enter the workings in an attempt to observe and sample the mullock between the lodes operated by the early miners. This objective was achieved on the third attempt. Samples were taken and subsequently a contract geologist resampled the workings and prepared a report indicating the Bullendale lode zone to be generally mineralised. Mullock interlode and schist foot-wall consistently returned assays over 0.5 g/t.

Jan 1, 1992

The literature pertaining to the electrochemical reaction at the anode during electrolytic reduction of alumina by the Hall-Heroult process is not in universal llgreement about the gaseous product. The possibility of electrochemical formation of CO at the anode was examined using existing data. Although the thermochemistry favours co-evolution of CO and CO2 with CO as the major product, the mechanism of the reaction shows this is unlikely. Since the origin of CO can be more logically explained by non-electrochemical mechanisims, it is concluded that CO2 is the only product from the electrolytic reaction at all current densities.

Jan 1, 1967