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By J Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration in small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using e-Dev™ electronic detonators in a typical mining application was conducted at Resolute’s Mt Wright operations in North Queensland in 2010. Results were based on direct comparisons to the current industry standard of non-electric firings as a baseline, with as many parameters as possible being captured during the trial. Development costs are typically high in most underground mines, especially in capital development headings, which are in waste and therefore of no direct economic value, so by being able to accurately fire to design, costs relating to both ground support requirements and volume of material removed, (and therefore haulage required) can be minimised. A direct comparison of overbreak (ground blasted outside of design) and cast (distance rock thrown from blast) was also made during the trial, as well as close monitoring of the drilling accuracy.

Mar 21, 2011

By D Price

Mining at the Tuckabianna Mining Centre in the Murchison district of Western Australia ceased in 1997, after the production of 550 000 ounces of gold at an average grade of 2.5 g/t from 22 separate open pits (Tectonic Resources, 2006). Like many historic mining camps in WA, Tuckabianna was considered exhausted of gold, such that an economic project could not be sustained on the existing resources. Since 1997, three separate companies have owned the Tuckabianna leases. Each of these companies completed minor exploration and some form of mining study to determine if mining could be sustained. All three companies concluded that the remaining resources were insufficient to support an economic project. Silver Lake Resources acquired the adjacent Tuckabianna, Comet and Moyagee projects in 2007 with a combined resource base of 693 000 ounces of gold in 11 separate deposits. In September 2009, Silver Lake commenced exploration in the Murchison targeting extensions to the main resources at the three project centres and completing targeted regional exploration across the lease holding. At the same time, a detailed evaluation of all historic drill data was completed and all resources re-estimated. This has culminated in the resource base increasing to 1.5 million ounces of gold in 20 separate deposits, with two new discoveries being made. In August 2010, a mining feasibility study was commissioned. Preliminary results from the study indicate that an economic stand alone project can be sustained for a minimum of five years. The ability to bring the remaining resource from a once unloved project into production is due to a number of factors: historically high gold price, combining adjacent projects into a single operation, evaluation of all resources regardless of size and grade, and well funded exploration directed to both resource extensions and new discoveries. Using the Tuckabianna Project as an example, this paper attempts to outline the strategy Silver Lake used to define the resources to justify the capital expenditure required for production, and give a summary of some of the successes and failures made as the projects progress towards mining. Examples of where being too rigid and over exuberant have resulted in less than optimal use of expenditure are used to high-light the difficulties in exploring in mature terrains. Evaluation of the success of a company’s exploration strategy at all scales from project acquisition to target selection is critical to the success of future project development. This paper has been part of that process for Silver Lake with some interesting discussions and insights being made. It is hoped that some of the points discussed can be applied to other projects to help achieve the best outcome from the assets available to a company.

Aug 22, 2011

By A Giblett, S Hart

"In 2015 operations under the ownership and/or management of all Newmont Mining Corporation subsidiaries (Newmont) produced 5.7 Moz of gold and 619 Mlb of copper from mining operations in five countries, with well over 100 Mt of ore processed by various grinding technologies. Processing methods used in the extraction of metals include flotation, oxidation, conventional cyanidation and heap leaching. The grinding technologies applied in milling operations feeding metal recovery processes include conventional wet grinding semi-autogenous grinding (SAG), rod and ball, dry grinding, concentrate regrinding and ultra-fine grinding, and ball milling of high pressure grinding roll product. SAG/ball (SAB) configurations represent the dominant comminution flow sheet within the company and the circuit configurations employed include SAB, SABC-A, SABC-B and single-stage (SS) SAG milling, with SAG mill feed ranging from run-of-mine (ROM) ore through to secondary crusher product. The collective experiences earned from designing, operating and debottlenecking these various comminution circuits provide many lessons that can be applied to the design and optimisation of future operations. This paper provides an overview of Newmont’s diverse comminution circuits, discusses recent performance and offers some insight into optimisation and design considerations based on recent experience in both endeavours.Citation:Giblett, A and Hart, S, 2016. Grinding Circuit Practices at Newmont, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 293–302 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

The Rio Tinto Iron Ore group currently estimates grade attributes for mineral resources using ordinary kriging (OK). OK produces a smoothed globally unbiased estimate, but does not capture local variability, which can have significant impact on mine planning and scheduling. The dimensions and the multivariate nature of iron ore deposits make point simulations of whole deposits impractical. With a direct block simulation method the size and speed limitations of point simulations can potentially be overcome, resulting in a viable method for capturing local variability and for providing risk measures into the mine plan and schedules. Some iron ore deposits are highly folded (post mineralisation) and require preprocessing using an unfolding algorithm to properly define the continuity parameters and directions of anisotropy before simulation can proceed. Block co-simulation proceeds in unfolded space and since mine planning require a block-model with regular block-sizes; a regular block-model is unfolded first. This paper discusses a block co-simulation approach that can be used to simulate the irregular blocks resulting from the unfolding process. A section of an iron ore deposit is used for testing the block co-simulation algorithm and the simulation results are compared against the Isatis direct block simulation method. Available blasthole data is also used to validate the behaviour of the block co-simulation algorithm.

Sep 26, 2011

By P Thwaites

The mining industry uses many types of mineral and metallurgical plants to produce saleable product from ore mined. Plant design history has left current operations with a mixture of manual operation and various forms of automated process controls. Consequently, we typically see high-variability in the continuous operations together with a shortfall in the attainment of full capacity or higher utilisation of consumables.At a level of best practice, ‘operational performance excellence’ focuses on process control, using automation and control systems to deliver process optimisation. This more sophisticated delivery is a great deal more difficult than the first stage of equipment selection/installation. It includes the appropriate selection of the right instrumentation and control system, key process knowledge, individuals with a solid control engineering background/experience and the essential backing/support of the operations management team together leading to higher-value delivery. Robust solutions can be realised, considerably minimising process variation, thus leading to process optimisation. This approach results in an easier, efficient and safer process while providing considerable returns for the plant owners.How variable are your processes, and do you maintain optimised process performance with dedicated resources, modern instrumentation, ‘best practice’ control systems and performance monitoring tools? In this paper, these questions and their possible answers are discussed.I say we can do much more and be ‘more efficient’ in our efforts to remain competitive. This area remains a major opportunity for improved efficiency, minimising tailings losses and other milling costs.CITATION:Thwaites, P, 2014. Manual control, process automation or operational performance excellence – what is the difference?, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 13–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

The Kalgoorlie Golden Mile is proposed as an Archaean volcanogenic-type deposit, modified and redistributed along later-developed structures. Rich pyritctelluride and Green Leader gold mineralization is associated with the end phase of basic volcanism and, in a general sense, is confined to a broad interface zone between the products of marine basic volcanism and later acid volcanism. There is virtualIy no ore associated with the main body of acid volcanics.Green Leader is the local name of a type of ore that occurs at some igneous rock contacts in association with graphitic sediments and layered acidic tuffs. It is characteristicalIy green, of various shades, and commonly yields very high gold assays, the reasons for which are not apparent in hand specimen.Carbonates, carbonaceous shales, tuffites, rich gold ores, and acid and intermediate dykes, alI indicating a common heritage, are features common to the main ore hosts, viz. the Paringa Basalt (Calc Schist) and theGolden Mile Dolerite ("Quartz Dolerite Greenstone").Several probably related fracture systems have reconstituted most, but not all, of the original deposits into a large number of steep tabular lodes.Includes two sets of discussions and comments from later Proceedings volumes.

Jan 1, 1974

By R G. Jeffrey

The Northparkes, Endeavour 26 orebody is a porphyry copperûgold deposit and comprises a moderately to well jointed rock mass characterised by gypsum veining, the intensity of which decreases with depth. The top 480 metres of the orebody is currently being mined by block caving, the undercut dimensions measuring 196 metres in length by 180 metres in width. Continuous caving was never achieved after the completion of the undercut thus cave inducement techniques were sought to maintain caving so as to safely sustain production. The use of hydraulic fracturing as a cave inducement tool was successfully trialled in December 1997 using existing exploration boreholes located midway up the current lift. Subsequent fracturing campaigns have enjoyed various degrees of success and have yielded in excess of seven million tonnes of ore at a significantly lower cost than conventional cave inducement techniques. Monitoring of both the hydraulic fracture system and the rock mass response has provided considerable insight into the geometry, growth and influence of hydraulic fracture networks above the Northparkes block cave, and has initiated additional research into the use of hydraulic fracturing in other mining methods.

Jan 1, 2000

By V Matousek, A Sellgren, R Visintainer, G McCall

A 4-component model for settling slurry pipe flow has been previously described by Wilson et al (2006) and Sellgren et al (2014) to predict pipeline friction loss (hydraulic pressure gradient) over a range of slurry compositions: from fine to coarse particle size, narrow to broad particle size distribution, and low to high solids concentration. The method applies a weighted average of established pipeline models for various settling slurry flow regimes, according to the volume fraction of solids falling within the applicable size range for each model. Further development of the model was undertaken by Visintainer et al (2017a, 2017b), based on a comprehensive set of laboratory tests in 203 mm (8 inch) and 103 mm (4 inch) pipelines, and it was also adapted to the modelling of slurry pump performance derates. However, this work was all performed with solids having a specific gravity near 2.65, as is typical for many mineral processing and dredging applications. The goal of the present work is to test the applicability of these models for settling slurries having a higher solids specific gravity, as may often be seen in the mineral processing of iron ore deposits. To that end, a test program was carried out in a 103 mm (4 inch) pipe loop using various compositions of an iron ore product having a solids specific gravity of 4.75 and containing both coarse and fine solids. By screening and flushing operations, a range of particle size distributions were created having different proportions of the coarse and fine elements. In all, 19 tests were performed with d50 particle sizes ranging from 50 μm to 3.2 mm and delivered solids concentrations from 10 per cent to 43 per cent by volume. Particle size distributions varied from very narrow to very broad, with d85/d50 ratios ranging from 1.75 to 26. Pipeline pressure gradient and pump performance data were collected and used to test the applicability of the previously developed 4- component models and to propose improvements to the models for the handling of high-density solids.

Nov 8, 2021

By D Bertoldi, C Haines

"The Waihi Gold Mine (WGM) operated by OceanaGold New Zealand Limited is a wholly owned subsidiary of the OceanaGold Corporation of Australia. Traditionally WGM has stockpiled and processed separate campaigns of open pit and underground ore. The ore is processed via a conventional semi-autonomous grinding (SAG) / ball circuit (SABC). The low aspect SAG mill operates in a closed circuit with two 20" cyclones, whilst the ball mill is also a closed circuit with a 10" cyclone cluster. A major wall movement in April 2015 ceased open pit operations indefinitely, 18 months ahead of the mining plan. This immediately reduced the forecast mill tonnage leaving two options: begin campaign milling or change the operating strategy and target lower throughput. Additional cost pressures necessitated improved milling cost efficiency. The immediate ore restriction limited processing alternatives to within the existing major infrastructure. Available comminution circuit survey data laid the foundation for developing a comminution model using the JKSimMet™ software package (version 6, created by KJTech). A number of flow sheet variants were then evaluated based on predicted throughput and efficiency. The comminution models suggested opportunities for improved efficiency lay in reducing throughput and increasing utilisation rather than on/off campaign milling under the existing operating philosophy. A series of process alterations followed, delivering new cost efficiencies that maintained the current $/t processing cost. This paper aims to review the change in circuit performance and examine the decisions and challenges faced following the transition from a high tonnage SABC circuit to lower tonnage SABC circuit.Citation:Haines, C and Bertoldi, D, 2016. The Transition from Semi-autogenous to Autogenous Milling at Waihi Gold, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 303–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

Any Australian who knows of the poverty of the early settlers in the first few years following the arrival of Captain Arthur Phillip with his "first fleet" at Botany Bay must feel proud of the progress that has been made in the 174 years that have elapsed since that momentous occasionGFor all its attractive appearance as reported by Captain Cook and Sir Joseph Banks, the shores of Botany Bay and of Port Jackson proved most ,inhospitable, and the accessible country surrounding them anything but suitable for sustaining the life of the small settlement. It is well known that during the first 15 or 20 years the hardy colonists and un-tfortunate convicts were close to starvation on several occasions and were only saved by the arrival of supply ships, which were dependent on the vagaries of wind and current, and the hazards of the uncharted seas they had to -navigate-.When Australia was little more than a miserable penal settlement, Great Britain was one of the great-powers of the world, and the U,.S.A. was an independent nation with a growing degree of prosperity that even then gave promise of its mighty awakening to become, as it has, a e.olossus of industry and commerce,-and the. leader in living standards of the world to-day.Australia, from such a shaky, and comparatively recent start, has risen to a position in which its living standards rank very high in comparison with those of most of the nations of Europe and America. Exact com-parisons are hard to fix because of the wide variety of factors involved .but the Institute of Pab?Lic Affairs .(Victoria) places Australia fifthin the world, excelled only by the U.S.A., Canada, Sweden and Switzerland. The next best after Australia are the United Kingdom, West Germany and France.How we achieved such a high standard of living is a vast subject for study but some of the economic aspects of our climb from abject poverty to a position of near affluence can readily be identified.

Jan 1, 1962

By Servant S

In the mine of this study, cemented hydraulic backfill is placed under the form of a slurry at a percentage of solid by weight varying from 50 to 65 per cent. This slurry settles and cures in the stope. During this process an important amount of water must be drained from the scope. Field observations in the case studied here show that the geometry of the drains system has a significant impact on the drainage of the stopes. The mode of filling produces a backfill showing an evident stratification typical of a sedimentation process. In situ observations on this material show that this stratification translates into a very strong heterogeneity in the physical properties of the cemented backfill. This heterogeneity should affect the hydraulic conductivity of the backfill in the scope. In order to study this aspect, finite element simulations were performed. This paper presents the results of these simulations, where the impact of this stratification on hydraulic conductivity is related to the performance of the backfill drainage system for various geometry. This preliminary study is aimed at providing a better understanding of the role of the drains in the dewatering process of the backfilled stope in the case of this Mine.

Jan 1, 1998

By M Armony, J F. C L Costa, J C. Koppe

Linear kriging methods fail to estimate local grades and local reserves for highly skewed variables due to three reasons: it uses only part of the available data information, it has no physical principles associated with the mathematical proceedings to minimise the problems, and it works with continuous variables while data are discrete because of the limited precision of any equipment. The techniques commonly used up to now to solve the highly skewed variables estimation problems were unsuccessful, unless mathematical rigor is abandoned. Even the method of multiple indicator kriging is not satisfactory. This paper presents a new framework, the field parametric geostatistics (FPG) that transforms noisy variograms into well-behaved variograms and justifies mathematically empirical procedures commonly used, as trimming or capping arbitrarily very high values. The method, when applied to non-skewed variables, yields similar results to classic kriging. The methodology is illustrated in a case study at a gold deposit in Brazil, and compared to results obtained by usual techniques.

Sep 26, 2011

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 J Bassan

The mining industry is faced with imperatives to improve worker safety and productivity, adapt to skills shortages, high worker turnover rates, and provide more effective maintenance to new and ever more complicated plant and equipment. While more effective use of data combined with advanced analytics offers opportunities for improvement, providing this information to the worker in the field, in real-time, has proven expensive, cumbersome and ineffective. New capabilities are now emerging which address some of the limitations experienced to date. Augmented reality (AR) provides a means to overlay interactive digital information on top of the physical world. Combining the latest visual display, mobile computing and ‘track and trace’ technologies, AR provides an experience similar to a heads-up display in a fighter jet through small, personnel devices, such as smart phones or wearable glasses. Applying AR would allow a mobile worker to ‘see’ all relevant information for a given task, in the context of their physical environment and at the time they require it. The technologies behind AR are rapidly maturing and becoming available at a price point that is viable for commercial applications. It is anticipated that AR will become ubiquitous at a consumer level within the next five years. The specific challenges faced by the mining industry make it an ideal early adopter of AR technologies. This paper examines a number of use-cases of how AR can be applied to the mining industry and the benefits that can be realised. The paper will identify areas of further work and viable opportunities for immediate adoption within the industry.

Nov 22, 2011

The New Broken Hill Consolidated Airshaft is the first major undertaking in the development of New Broken Hill Consolidated Ltd's. property, which adjoins that of The Zinc Corporation Ltd. on the latter's southern boundary.The Zinc Corporation ore-body has a southerly pitch. The Zinc Corporation's New Main Shaft is 1000 ft. north of the common boundary, and the general plan of development of the New Broken Hill Consolidated property is by driving south from this shaft on the lower levels. No downcast airway from the surface was available south of the Zinc Corporation's New Main Shaft; this shaft acts as the main downcast to the bottom of the Zinc Corporation mine, the general air flow then being northward and upward to the upcast shaft at the extreme north end of the Zinc Corporation property.Rock temperature is 920 F. at 2000 ft., increasing by 10 Fahr. each 72 ft., the rock temperature at 3000 ft. being estimated at 1060 Fahr. With the general air flow northward from the Zinc Corporation's New Main Shaft, adequate ventilation under these temperature conditions would not be practicable for any great distance south of this shaft without another main airway from the surface. Accordingly the New Broken Hill Consolidated Airshaft is being sunk at a point 1000 ft. south of the common boundary, i.e., 2000 ft. south of the Zinc Corporation's New Main Shaft, to ventilate future New Broken Hill Consolidated workings and that part of the Zinc Corporation mine between the boundary and the New Main Shaft.

Jan 1, 1940

By S Gossmann, J Barlow, S Denner

"Unconventional gas resources, including coal seam gas (CSG) reservoirs, can be located above and below aquifers that provide groundwater for agricultural, industrial, urban and other uses. Development of these resources may, therefore, lead to potential impacts on groundwater supply.Management of reservoir/aquifer interconnections necessitates a program of focused data acquisition. For example, groundwater transfer from shallow aquifers to underlying CSG reservoirs may occur where CSG-containing units subcrop beneath shallow aquifers, possibly at significant distances from operating wells.Arrow Energy is undertaking studies of connectivity between aquifers including an investigation in collaboration with the Queensland Office of Groundwater Impact Assessment to evaluate connectivity between the Condamine Alluvium (CA) and CSG-containing Walloon Coal Measures (WCM).The Condamine Valley hosts highly productive agricultural land with groundwater resources heavily utilised for irrigation. Water demand outstrips available supply and groundwater has been subject to restrictions on further development since the early 1970s. Developments that could have an additional impact on groundwater resources in the CA are of major concern to local landholders. This paper describes: planned field investigations at two sites: 1. Stratheden, where pumping from the WCM will be undertaken 2. Daleglade, where pumping from the CA will occur how the data to be collected from field investigations will be used to refine predictions of flux between the CA and the WCM.CITATION:Denner, S, Gossmann, S and Barlow, J, 2013. Planned field investigation of connectivity between the Condamine Alluvium and Walloon Coal Measures, in Proceedings Water in Mining 2013, pp 91-98 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

ABSTRACTFor the binary system copper-lead two relationsEquation 1andEquation 2have been derived for the activities of copper and lead at compositions and absolute temperatures within the liquid region of the phase diagram.These relations give, with greater accuracy than is given by previously published relations, the activity-composition temperature variations for all regions of the phase diagram of interest to metallurgists.These relations are essentially simple forms of the Margules equations but with linear temperature dependence applied to their coefficients. This has been done in such a manner that a phase diagram obtained from these relations agrees well with the data available for this system. The methods of obtaining the relations and constructing a phase diagram from them are both given in detail. The enthalpies and entropies of mixing are compared with those derived by other methods.

Jan 1, 1971

By B Tutmez

Determination of stress-strain behaviour of rocks plays a crucial role in understanding the response of rocks during loading. However, it is a tedious, expensive and a time-consuming process to obtain such characteristics both in the laboratory and in situ. On the other hand, non-destructive testing methods such as ultrasonic velocities can produce a reliable and fast solution to indentify state of strain and stress in rocks. The present paper aims to provide insight into the relations amongst ultrasonic wave velocities, amplitudes and deformability properties of porous siltstone under compressive loading. For this purpose, pulse (vP) and shear wave velocities (vS) along with amplitudes (AP - AS), and applied loads with resultant strain were measured simultaneously so that response of siltstone to compression can be evaluated. In addition, initial vP and vS were recorded at the beginning of each test to calculate dynamic elastic properties of the specimens. This provided a comparison between static and dynamic elasticity properties of siltstone. Crack damage associated with the onset of dilation was also investigated. The results showed that there is a non-linear logarithmic relation between velocities and stress-strain level for siltstones.

Sep 26, 2011

By S S. Kanchibotla, I Brunton

Most blast fragmentation models assume the rock mass properties, explosive properties and blast design variables to be constants and uniformly distributed within a blast. However, in reality all these input variables vary within a blast resulting in variation in the resulting fragmentation size distribution. A stochastic modelling approach is introduced in this paper to quantify this variation. This technique takes the input variables as statistical distributions rather than constants and through several thousand iterations, generates a statistical representation of the expected fragmentation resulting from a production blast. A case study of three production blasts from a large open pit mine are presented and the modelled fragmentation æenvelopeÆ shows good agreement with the fragmentation æenvelopeÆ estimated from Split image analysis. The various blast-related parameters influence different parts of the fragmentation distribution, eg rock strength and explosive velocity of detonation have most impact on the fines. The technique is used to identify the parameters that have the greatest influence on various size fractions. Such an analysis will be useful to direct resources to efficiently minimise the variation.

Jan 1, 2001

By J E. Wajon

This paper discusses the background, requirements, need and content of plans for management of drinking water self-supplied to mining-related operations, including construction camps, especially in remote areas of Western Australia. The paper discusses the importance of cooperation between regulators, the mine site operator and the consultant in preparing a plan fully compliant with the Australian Drinking Water Guidelines to protect the quality and safety of drinking water supplied to mine sites. The paper outlines some of the issues that need to be addressed in preparing a drinking water quality management plan, such as hazard identification, risk assessment, the multiple-barrier approach and the concept of critical control points. Data requirements, monitoring, incident management, training and reporting are also covered.CITATION:Wajon, J E, 2013. Drinking water quality management for mining operations in Western Australia, in Proceedings Water in Mining 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013