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A rotating disc of precipitant zinc in a single stage flow reactor was used to study the effects of deposit mass on the reaction kinetics of copper cementing on to zinc from dilute aqueous solutions.The reaction rate is controlled by external mass transport and the mass transfer coefficient (relative to the original precipitant area) is dependent on the quantity of deposit present. For deposit masses up to about 0·3 mg/cm2 the mass transfer coefficient (first order rate constant) is that expected for the counter-diffusion of reactant and product cations through a laminar boundary layer to a smooth rotating disc. For depositmasses from 0·3 mg/cm2 to about 5 mg/cm2, the mass transfer coefficient increases significantly with deposit mass. For deposit masses greater than 5 mg/cm2 and at least up to 12 mg/cm2, the mass transfer coefficient has again a constant value which is some four to seven times the initial ("deposit free") value. The rate constant for the entire range of deposit masses studied (0 to 12 mg/cm2 ) can be expressed empirically as a cumulative normal distribution of the logarithm of the deposit mass.The enhancement in the mass transfer coefficient for deposit masses greater than 5 mg/cm2 relative to the initial mass transfer coefficient depends on the local operating conditions and increases with increasing disc rotational speed. This enhancement is, however, independent of the previous history of reaction rates.

Jan 1, 1973

By R B. Stewart

Where pasture production is the intended land use of the areas to be reclaimed, the creation of a suitable growing +medium is a major objective. To achieve this land reclaimers require a sound understanding of the proposed mining plan and a knowledge of the physical, biological and chemical properties of materials intended for resurfacing disturbed areas. Where the original soil is not being replaced in its natural state, research is usually required to determine an alternative growing medium. Results from field research conducted on waste material from the Waihi Gold mine are reported with emphasis on the significance of soil depth in relation to pasture production in this environment.  Problems in extrapolating field research to large scale operations are also considered.   Essentially the requirements for successful pasture production, on surrogate growing medium, are akin to conventional approaches used in New Zealand in the development of unimproved agricultural land. High inputs of fertiliser are initially needed, especially where volcanic soil is used, and careful management of pastures and soils is required to minimise soil erosion and create a sustainable system. In the first three to five years of pasture production, grazing use of the land requires to be dictated by pasture availability and soil conditions and not by animal feed requirements. The use of light stock (young dairy or sheep) is recommended.   Successful land restoration requires a team approach by a range of cooperative specialists including engineers, soil scientists, farm managers, agricultural contractors, landscape architects and environmental officers.

Jan 1, 1991

By S G. Gemell

"The financial model is an integral component of any project evaluation based on mineral resources, ore reserves and (at least internally) exploration targets. Given the unity of purpose for preparing financial models for project evaluation purposes, the diversity of both format and content of the finalised models is surprising. Many models are prepared by staff or consultants who are comfortable with a particular format that may be used for other purposes, such as budget preparation or financial reporting. It is natural in these situations that the practitioner will take these models and adapt them to the purpose. The end result may or may not succeed in providing a clear, accurate and sufficiently detailed view of the project’s economic viability.When preparing a model, the practitioner should be cognisant of the interpretation and review, or audit, process. The auditor may be a consultant or employee of a bank, potential equity provider or of the project sponsor itself. Depending upon the scale of the project and the level of participation of the entity that the auditor represents, the financial model will be interrogated more or less rigorously. In any event, the end user will require the model to permit easy change of inputs and will wish to confirm that such change is appropriately and thoroughly transmitted throughout.Accordingly, there are some ‘dos and don’ts’ that can be readily applied in the creation of the financial model that will greatly assist the end user, not just in the change of inputs, but also in reviewing the model’s integrity. The less time and effort required by an auditor in this regard is reflected directly in the cost of the review process.CITATION:Gemell, S G, 2016. Financial modelling with the auditor in mind, in Proceedings Project Evaluation 2016, pp 172–180 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

An understanding of the way that solutes are transported in mining or natural environments is essential to the development of sound strategies for managing waste disposal. Research on miscible pollutant movement in unsaturated porous media is carried out both experimentally and numerically. Results of numerical modelling are obtained by solving the groundwater flow equation and the solute transport equation. The finite element method is employed and comparisons between simulation results and experimental data are found in remarkable agreement.

Jan 1, 1995

By E Widzyk-Capehart, C Hölck Teuber, S Steffen, V Rivero, O Fredes, E Sanchez, I Pedemonte, N Gonzalez

This paper summarises the research, development and initial application of a sensing platform that has the potential to monitor subsurface deformations, pore pressure and other variables simultaneously to gain a better understanding of rock mass behaviour. The platform is based on Networked Smart Markers (NSMs) devices, which, with their ability for wireless communication between individual sensors and the possibility of real-time data acquisition and processing, will assist in the development of predictive tools to better assess rock mass behaviour.A good opportunity to implement this technology is in the specific application of transitioning from an open pit mine to an underground caving operation. One of the key elements to maintaining the mining business during such a transition is having a good understanding of the unique geotechnical conditions of mutual influence created during the open pit to underground interaction. The knowledge acquisition will require the implementation of a robust platform for geotechnical monitoring, which could be enhanced by incorporating the NSMs. The integration of sensors within the NSMs would enable the collection of additional data about rock mass behaviour (ie caving propagation and crown pillar fracturing), which could be used to improve the management of mining operations and, specifically, allow the development of reliable predictive tools based on the data collected.CITATION:Widzyk-Capehart, E, Hölck Teuber, C, Fredes, O, Rivero, V, Sanchez, E, Pedemonte, I, Gonzalez, N and Steffen, S, 2016. Understanding rock mass behaviour through the development of an integrated sensing platform, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 275–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Acoustic Emission Monitoring of Froth Flotation

Sep 13, 2010

By N Hungerford, A Coote, S Doyle, D Henderson, F Della-Pasqua

A systematic, detailed airborne geophysical programme carried out in the Taupo Volcanic Region (TVR) in 2005 by Glass Earth NZ Ltd culminated in the identification of 21 epithermal gold targets. In this paper we present the follow up ground-truthing results from the first target drilled, Tahunaatara (TAH).   The Tahunaatara target was identified by means of a multi-disciplinary integrated approach (ôdata interventionö) that defined and ranked the target as being highly prospective for epithermal gold mineralisation. A follow-up ground resistivity survey over the target area revealed the presence of a ôresistorö buried beneath an extensive cover of recent volcaniclastic material. Geochemical soil sampling carried out in conjunction with the resistivity survey yielded anomalous gold values.   The host unit at TAH consists primarily of flow banded rhyolitic lavas, volcaniclastic deposits and tuffs of the Ohakuri Ignimbrite with small outcrops of silicified bedded breccias forming local topographic highs. Results from the first orientation drill hole show wide zones of intense silicification, clay alteration and mineralisation. Sulphide mineralisation is disseminated throughout the core in association with hydrothermal replacement and also occurs in association with quartz veins and infill in fractures (sulphide-only veinlets as opposed to quartz + sulphide veinlets). Textural evidence from drill core indicates that hydrothermal fluid flow was multi-staged with potential for multi-stage gold, and other elements. The presence of polymictic hydrothermal eruptive breccias indicates a hydrothermal vent system.   Alteration varies from argillic to silicic, with pervasive adularia and vuggy silicification also present. Chlorite is minor and associated with quartz, illitic clay and adularia. Assay results currently available confirm the presence of anomalous gold values in association with zones of vuggy silica deposition and intense silicification.

Jan 1, 2006

Role of Bubbles in the Action of Flotation Agents

Sep 13, 2010

By H Rossiter, A Maddever, J Market, P Jeanneau, A Virani

It is generally acknowledged that the head grade of the world’s copper resources is declining. Accordingly, there is an increase in the volume of resource material being mined and processed to maintain copper production. This has led to increases in cost base accompanied by reductions in Life of Mine (LOM) Net Present Value (NPV). The higher tonnages of material mined are driven by increased quantities of lower grade material required to satisfy the short term mine model. In turn, this has brought an increased focus on sampling and assay methods, since any error associated with estimating the grade of each block and determining its correct destination serves to magnify the losses that will occur. Presently most open-pit copper mining operations use blasthole sample assays to feed their shortterm model. The problematic nature of blasthole sampling is well documented (Engström, 2017), particularly the poor timeliness of the data and the significant errors that are inherent to the technique. Methods to improve grade control, such as drilling a separate grade control grid, have been proposed but come with their own cost, logistical, and accuracy shortcomings. A recent development in grade estimation is the Pulsed Fast and Thermal Neutron Activation (PFTNA) downhole logging probe. Deployed on an efficient semi-autonomous platform, PFTNA is being aggressively adopted in the Australian iron ore industry. The technology provides in-situ elemental analysis of the geological formation, delivering high accuracy, high efficiency, near realtime data from a sizeable measurement volume. In this paper we consider the application of the technology to copper. Whilst there are several operational components to such a value proposition, we focus on the benefits of improved gradeestimation. A simulated copper mine is used to model the quantum of improvement expected from a reduced grade-estimation error, which reduces the likelihood of misallocating material to the wrong destination, which in turn increases NPV.

Nov 10, 2020

By S Das

Deposit-10/11A is situated in the iron rich Bailadila region of India comprising haematite ore of average grade 65 per cent Fe. The deposit production line was commissioned in the year 2002 having a capacity of 5 Mt/a. The plant has the state of the art mineral processing equipments.The ore is transported from mines to crushing plant by means of dumpers. The ore is comminuted in two stages to get 150 mm top size product and this product is transported through conveyor system and is stored in silos as feed stock for beneficiation plant. In the beneficiation plant this crushed product is wet screened in two stages to produce a product of lump (-150 + 10 mm) and fines (-10 + 3.15 mm). The product of -3.15 mm top size is fed to primary classifier for a size separation at 150 µm. The resultant product (-3.15 mm + 150 µm) is dewatered and transported to fi ne ore product stock yard through conveyor system. The minus 150 µm material from classifier overflow is fed to cyclones (508 mm cyclone battery with an apex of 65 mm) for desliming at 45 µm and to recover ultrafi nes (-150 + 45 µm). The cyclone overfl ow slimes (-45 µm) along with water is treated in lamella thickeners to recover process water. The thickener underflow material is transported to tailing pond (discharge rate is 300 m3/h at a specific gravity of 1.4) by pumping through HDPE (high density poly ethylene) pipeline and the over flow water is being recirculated. The water requirement for beneficiation is approx 1.5 m3 per ton of ore.This paper aims at identifying and quantifying the factors that affect the overall plant performance (grade and recovery) during the different seasonal variations especially in the rainy season (mid-June to end October). The effect of seasonal variations on unit operations such as milling, classification, thickening and filtration are discussed. Specific cases are presented as examples and recommendations are formulated.

Jul 11, 2011

By W Mahoney, F Clement, E Saraiva

Prefabricated waterproofing sheet membranes are extremely complicated to install in underground sections with complex geometries and, despite being already subjected to quality tests in the factory, the installed membrane often exhibits leakages due to different reasons. Main sources of leaks are the required high amount of welding seams and damages caused during installation of reinforcement, as well as overstretching and poorly installed secondary concrete linings. Also the design of the tunnel lining is strongly influenced and limited by the use of prefabricated waterproofing sheet membranes. The use of sprayed waterproofing membranes for more than a decade has contributed to durability and serviceability, as well as to increasing sustainability of tunnel linings. The presented sprayed waterproofing membrane MasterSeal 345 is an advantageous alternative to prefabricated waterproofing sheet membranes under typical tunnelling conditions, especially in geometrically complex areas, such as in lay-by niches, cross passages and crossover caverns, where installation of conventional waterproofing membranes is inherently difficult, and locating leaks is challenging. This membrane has been successfully used in underground projects with different waterproofing design concepts and under diverse hydro-geological and environmental conditions for over a decade. It provides tunnel designers with different options and optimisation for the design of the tunnel concrete lining. Additional advantages to owners, contractors and designers from the use of the sprayed membrane include flexibility in the design, increased productivity and flexibility in working programming, as well as improved logistics, resulting in significant program and cost savings and reduced long-term maintenance costs. This paper describes the key features of this sprayed waterproofing membrane, its application range and limitations, the waterproofing concept, design options and related benefits. Further, guidance for membrane application and quality control and a summary of two recent project references in the United Kingdom and in Switzerland are provided.CITATION:Saraiva, E, Clement, F and Mahoney, W, 2014. The use of sprayable waterproofing membranes in underground structures – concept, design options, benefits and limitations, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 323–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J M. Galvin, B J. McKinnon

Lightning Ridge, Australia, is the largest opal producing area in the world. Most opal is mined from shallow underground mines by individuals or small partnerships with the industry having been protected from large-scale development to date. The safety performance of opal mining has lagged both general mining industry standards and community expectations. The application of geotechnical analysis to the opal fields has the potential to considerably reduce injuries and fatalities. With consideration of the local culture, preliminary geotechnical analysis has been applied to some current methods of work utilised at Lightning Ridge. Practical solutions have been advocated and are presented in this paper. Improvements to safety generated by these practical solutions indicate that further geotechnical research at Lightning Ridge is warranted and would be beneficial.

Jan 1, 2002

Open pit mining at Bingham Canyon commenced in 1904 and about two billion tonnes of ore have been extracted since then. There remain just under one billion tonnes of ore in the pit and this will be mined by 2015. Because the porphyry system extends below the ultimate pit limits, Kennecott Utah Copper Corporation initiated a study in 1997 to determine the viability of underground mining. The study was initiated at that time because the results were to be used to compare the economics of a further pit expansion to that of an underground mine. If a pit expansion was viable then overburden removal would have to start in the near future. This paper is a summary of the work that was carried out for the underground study. Block cave mining was determined to be the most appropriate method to mine the deposit. Two block cave areas have been planned with a total production rate of 72 500 tpd. Additional sources of ore will come from skarn orebodies that are associated with the porphyry deposit. The geology of the deposits is described together with the geotechnical techniques that were used to characterise the rock in the absence of more detailed data that are normally available. A general description of the mine plan is given along with the reasons for selecting the particular methodology used. The study was completed at the end of 1998 and demonstrated the viability of underground mining at Bingham Canyon. Funds have been approved for further drilling and technical studies, which will lead up to a feasibility study in 2004/5.

Jan 1, 2000

By C A. Heinrich, J L. Walshe, V J. Wall

The Porgera Gold Mine, located in the highlands of Papua New Guinea, has produced over 5 million ounces of Au, since its opening in late 1990. The deposit is located within Upper Cretaceous Papuan Platform sediments approximately 25 km south of the Lagaip Fault, and is spatially and temporally associated with the 6 Ma alkaline Porgera Intrusive Complex.

Jan 1, 1995

Tapira Mine (Tapira, MG, Brazil) is the largest phosphate ore and concentrate producer in Brazil. The mine is an open pit, which until recently operated with a large equipment fleet and now uses a smaller fleet operated by contractors. The annual production reaches 17 Mt of ore plus 14 Mt of waste at a stripping ratio of 0.82. Defining the geological boundaries and forecasting the annual production can be a difficult task if not performed on a reliable model. The geological model has been totally reviewed as well as the estimation process. Ordinary Kriging has been used to build the new block model with P2O5 and contaminant grades. After estimation, block model validation and classification criteria definition to assess resources and reserves, the result is given by the life-of-mine plan is defined after pit optimisation and design. The Lerchs-Grossmann algorithm implemented in the NPV Scheduler was used to define the long-term production targets based on the main parameters P2O5 and the contaminants that are just important to the beneficiation process.

May 1, 2010

By P Mulvey, M Stuckey

"Inter-aquifer leakage due to fractures caused by coal seam gas extractions or longwall mining is an important issue for both the gas and coal industries. Currently, predicting stress induced macro-porosity associated with hydraulic fracturing, depressurisation via dewatering or collapse of overlying seams to infill a void left by longwall mining, is problematic. If fractures can be located the fracture can be sealed. Locating fractures is difficult. The non-geophysical approaches to locate fractures has been to consider the mixing of different waters, particularly that of more recent shallower groundwater with older deeper groundwater, via differences in radio-isotopes integrated with geochemical models to predict likely mixing of waters. This approach is applicable under appropriately complex settings; however, it is an expensive technique and is based on the assumption that the daughter isotopes are equally non-reactive which may not always be the case.Potentially a cheaper and faster technique is to consider integrating geochemistry (mineral weathering) and hydrogeology. The chemistry of groundwater, controlled by the weathering of primary rock?minerals and?formation of secondary minerals, can not only be differentiated between geological strata but also within strata as different stages in weathering results in differing impacts on water quality (ie different reactants).Field analysis of pH, electrolytic conductivity (EC), oxidation reduction potential (ORP) and dissolved carbon dioxide together with laboratory analysis of dissolved constituents characterise the chemistry of the water. Collection of rock samples at the time of drilling for bore installation can provide the (only) opportunity to assess the media in which the groundwater resides and migrates through. An assessment of aquifer matrix chemical makeup, via bulk sample chemical analysis, X-ray diffraction (XRD) and petrographic analysis can achieve this.The chemistry of groundwater is dependent on the water velocity. Water at deposition and post-diagenesis dissolution of minerals by hydrolysis and oxidation will result in equilibria of the dissolved phase with the solid phase. Post-depositional fractures caused by either tectonic activity or weathering alter the rate of weathering and thereby the geochemistry. Slow water flow in microfractures results in water in equilibrium with the rock minerals. Faster flow in larger fractures results in water being in disequilibria with rock minerals.Fractures can alter groundwater chemistry by two pathways: changing groundwater velocity, which changes the rate of hydrolysis or oxidation mixing water from different geological strata.Both pathways cause subtle changes in the water chemistry.It is however, the dissolved phase chemical data, which can be observed over time at individual locations and/or at a point in time along a flow path, which allows the hydrogeologist to ælook up-gradientÆ and locate the zone of leakage. Hence, influences on rock/groundwater chemistry, from anthropogenic sources to natural mixing of waters, can be assessed via appropriate interpretation of geochemistry, hydrogeochemistry and flow data.This paper will use the example of the geochemical and hydrogeological characterisation of aquifers within the Hawkesbury and Bulgo Sandstone of the Southern Coalfields to the south of Sydney in New South Wales to demonstrate this approach.CITATION:Stuckey, M and Mulvey, P, 2013. Looking for fractures - integrating geochemistry with hydrogeology to find inter-aquifer leakage above dewatered or collapsed coal seams, in Proceedings Water in Mining 2013, pp 99-108 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By S Jokanovic, J L. Mauk

The Taharoa ironsand deposit covers approximately 16 km2 and is located 144 km south of Auckland on the west coast of the North Island, New Zealand. The heavy mineral-rich sands predominantly contain titanomagnetite, ilmenite and hematite, along with lesser amounts of amphiboles, pyroxenes, and feldspars. Throughout the Taharoa mine site 142 samples were collected of which approximately 25 samples were used in mineralogical analyses of the magnetic, heavy non-magnetic and light non-magnetic fractions. Mineralogical and petrographic analyses confirmed the high abundance of homogeneous magnetite and magnetite containing ilmenite exsolution lamellae which have oxidised to hematite. A limited number of sand samples were collected from Taranaki beaches. Petrography reveals exsolution textures of magnetite and ilmenite (now hematite), and homogenous magnetite grains similar to those observed at Taharoa. Petrographic analyses from previous research projects were also closely investigated in order to make mineralogical comparisons from along the west coast of the North Island and with other potential source areas. The origin of detrital magnetite grains along the west coast of the North Island is generally presumed to be the eroded volcanic cones of the Egmont volcanoes and active and dormant volcanoes of the central North Island. Electron microprobe analyses of magnetite grains from Taranaki beach samples reveal TiO2 values of between 1.5 and 120 per cent. MgO and A12O3 contents also vary widely from 0.75 to 6.5 per cent. This large variability may reflect different volcanic eruptions, the presence of exsolution textures or alternative source areas for these magnetite grains. Geochemical results from the Taharoa mine site correlate with the Taranaki beach samples suggesting that the Egmont volcanoes are certainly one source area. Variability in XRF results, especially Fe and Ti contents (9.04 - 59.22 and 0.80 - 4.64 respectively), from the magnetic and heavy non-magnetic fractions likely reflect the detrital nature of this deposit.

Jan 1, 2003

By using knowledge-based technology to create a Virtual Mining Enterprise and integrating it with existing technical and financial computer systems, a gold mining company has been able to reduce the time taken to produce a mine plan from 14 weeks to less than one week. Typically, the mine planning process requires circulating and managing large amounts of information. Even with the use of computers in todayÆs business, this is often still a manual process involving file transfers and individualised spreadsheets. Mine planning also involves understanding and managing large quantities of complex and interrelated variables. Added to this is the ever changing dynamics and constraints associated with the business of mining. These issues not only hamper the planning process but also question the validity and usefulness of the mine plans being generated. By integrating the information and knowledge of the numerous departments involved in mine planning into one core Knowledge Base - so called æone version of the truthÆ, - mining companies are able to overcome these pitfalls experienced in traditional planning methods. Once set up, the Knowledge Base creates and runs a virtual mining enterprise with which to visualise and test various scenarios of mining, business and logistical activities. The final output is an optimised enterprise-wide plan with clear and detailed instructions for each of the divisions of the company.

Jan 1, 2000

By P Cameron

MetPlant conferences have focused on ensuring mining projects are well designed then optimised to operate safely and effectively at the top end of world’s best practice to ensure shareholders are not just happy but delighted. This assumes the MetPlant was built right the first time. However, reality is, too often Plant Metallurgists (PlantMets) find after commissioning they are faced with the expensive task of correcting errors or modifying shortcomings to achieve product quality at name-plate capacity, i.e. get it right the second time. Why do companies spend good money to engineer an excellent feasibility study then allow “wise men” remote from the project team to impose cuts in budget and schedule, often under the guise of value engineering? Since mining is full of uncertainties, such actions can increase the risks of failure with the result that some MetPlants do not work well. Can PlantMets influence the remote wise men who often are also imposing the rules for lending and the required returns to appreciate the uncertainties of mining and their associated risks then let the project team get it right the first time? PlantMets can negotiate with the wise men from the outset of the project and bring them into an outer layer of the team where they can understand the risks then share responsibility and accountability to achieve the common goal of building a MetPlant which works well the first time and deliver the forecast profits. Since shareholders are not in the business to make losses they appoint a Board of Directors to deliver the best outcomes for the shareholders. Thus the Board should seek effective advice on the risk reward implications from the PlantMet before making their decisions.CITATION:Cameron, P, 2015. Do all metplants work well? PlantMets can ensure they do, in Proceedings MetPlant 2015, pp 2–9 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

A model was developed of a CIL/CIP circuit for recovery of gold and silver. The model uses a simple two rate representation of the leaching kinetics. Parameters for the leaching kinetics may be simply obtained by sampling the feed to a circuit and the tailings from each tank and assaying the solids for both gold and silver to obtain the assay profiles of the solids down the tanks. The parameters in such a leaching model would be expected to be a function of the ore type, the grind, whether oxygen was used and the general chemical environment. These parameters are primary inputs to the model for any simulation. Standard power law relationships are used to express the practical equilibrium between the gold and silver cyanides adsorbed on the active carbon and the tenor of the solutions. The parameters for this may be derived from solution and carbon assays for the same set of samples. The model is constructed by writing a mass balance for gold and silver in and out of each tank in the train and for the circuit overall. Other inputs to a simulation are the feed rate of ore, per cent solids of the slurry in the tanks, gold and silver loadings of the input æbarrenÆ carbon and the rate of movement of carbon through the circuit counter-current to the slurry. With appropriate practical parameters the simulation is able to reproduce typical tank profiles.

Jan 1, 2004