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By O. A. Bascur

Ores are becoming extremely variable with mineralogy and hardness disturbing the grinding and flotation circuits. The current grinding and flotation sensors provide large amounts of data for process optimisation. Adding the right context and operational events augments operational knowledge for proactive actions to improve the performance of the grinding and flotation circuits. A data-driven strategy is needed to enable operations, maintenance, and business personnel to quickly and easily take corrective action when abnormal conditions occur. A digital plant template transforms data into operational insights in real-time. It uncovers the hidden, idle and downtime losses. By measuring and managing these unproductive times, people find new ways of avoiding them, improving the profitability of the plant. The information created by the real time analytics enables the calculation of recovery in real time and develops predictive analytics models to find the best operating condition based on the type of ore currently mined. The creation of new workflows and collaboration between mining and concentrator plant and the enterprise, including services providers, are enabled. A grade recovery model is used to identify the best operating conditions in real-time. An optimal Gaudin size distribution shape is used to find the grinding operating conditions that optimise the metal recovery in the rougher sections of the mineral processing plant. Sensors in the flotation circuits enable estimation of metal recovery and determine the optimal froth depth and aeration profiles, using an industrial air holdup flotation model. The implementation of a recovery/grind strategy with industrial examples in non-ferrous metal concentrator is presented in the paper. Keywords: Digital transformation, soft sensors, predictive analytics, grinding flotation optimisation, flotation bubbles, particle size, particle size distribution shape, froth aeration profiles, flotation air hold up model, recovery predictive analytics

Jan 1, 2020

By D. F. Malan, D. Ile

This study explores the use of backfill in hard rock bord-and-pillar mines to increase the pillar strength and extraction ratio at depth. The use of backfill will also minimize the requirement for tailings storage on surface and the risk of environmental damage. A literature survey indicated that backfill is extensively used in coal mines, but rarely in hard rock bord-and-pillar mines. To simulate the effect of backfill confinement on pillar strength, an extension of the limit equilibrium model is proposed. Numerical modelling of an actual platinum mine layout is used to illustrate the beneficial effect of backfill on pillar stability at greater depths. The magnitude of confinement exerted by the backfill on the pillar sidewalls is unknown, however, and this needs to be quantified using experimental backfill mining sections equipped with suitable instrumentation.

May 3, 2023

By Ian MacKenzie

Over the past twelve years, professionals such as architects, engineers, accountants, and attorneys have not had to pay a great deal of attention to GST. The fees charged to clients (outputs) have not been subject to GST, but they have had to pay GST on al purchases of materials and taxable services relating to their activities.

Jan 1, 1990

By J. Galloway, P. K. Hofmeyr

Obviously all mining operations require much analytical work to be carried out. This starts with exploration, becomes more stringent with the evaluation of a mineralised area and finally becomes on-going when mining operations are under way. All these phases are carried out by geologists, metallurgists and mining engineers. They require analyses to carry out their functions but usually have no involvement in the analyses themselves. Analyses are carried out at commercial laboratories or in-house analytical laboratories. In the past in South Africa the tendency was for the larger mining houses to have their own centralised laboratories for exploration samples with each mine having it?s own laboratory to meet only that mine?s requirements. The centralised laboratory maintains QC functions at the subsidiary laboratories. In other mining areas of the world there has been a strong tendency for all geological analytical requirements, especially for exploration and mining, to be carried out at commercial analytical laboratories. In recent years there has been a tendency for mines in South Africa to move in the same direction. This paper discusses the factors that need to be taken into consideration when a new laboratory is being planned and automation is an option. The planning of the laboratory at the new Langer Heinrich Uranium mine in Namibia is discussed considering these factors. 2.0 REQUIREMENTS OF A MINING ANALYTICAL LABORATORY The purpose and requirements of a mining analytical laboratory are fairly obvious and can be summarised as follows :- 1. All mining operations must have access to analytical facilities, either in-house or commercial 2. The laboratory must be able to handle all the sample types submitted by the mining operation These can be mining, exploration and/or plant samples. They can comprise solids (rocks, bore-cores), slurries and/or liquids.

Jan 1, 2007

By I. Soto, E. Córdova, A. Anani

The new caving megaprojects that are planned to go into production in the next decade have scheduled horizontal developments at very high rates, which are difficult to achieve. Research has been conducted that seeks to model the construction times for underground developments to determine the feasibility of achieving the planned rates. However, these previous attempts do not consider all the operational aspects that make up the mine development cycle. Here, we present a discrete event simulation (DES) model that individualizes each unit operation of the development cycle to determine the construction rates that new projects will be able to attain. The developed model was applied to the New Mine Level (NML) of the El Teniente Division (DET). The results indicate that it would be impractical to achieve the advance rates scheduled in the original plans if the unit operations of the mine continue to be executed using the status quo. The metres developed after six years in the sections analysed can be significantly improved by changing the maintenance strategy for the equipment (457 metres increase), orepass availability (194 metres increase), and the initial planning sequence (1 598 metres increase). It is recommended that the mine implements a flexible maintenance strategy, defines a strategy to ensure and increase orepass availability to contractors, and makes use of current simulation tools for a more robust development sequence planning.

Oct 1, 2022

By G. Akdogan, T. P. Kekana, Q. G. Reynolds

The DC arc plasma gasifier concept is currently under development at Mintek for testing the feasibility of producing syngas from waste coal fines and dry steam. The technology is intended for the valorisation of low-grade discard coals into market-quality syngas, which may then be used for largescale electrical power generation to address current grid supply challenges in South Africa. Other potential applications include feedstock for petro-chemical plants, fuel for transportation vehicles, domestic and industrial heating, and others. The proposed concept of a DC arc plasma gasifier was developed based on a plasma torch, metallurgical-based and entrained flow coal gasifiers. The principles of design and operation of the proposed gasifier are based on the concept of the Westinghouse Plasma Corporation (WPC) gasifier where the torches are substituted by graphite electrodes from which electric arc plasmas are generated. The DC section of the gasifier will be designed considering Mintek’s experience in the sealing of the furnace as carried out in the Mintek Thermal Magnesium Process. As part of the building blocks of a full conceptual design, the feasibility of the DC arc plasma gasifier was investigated through testing and modelling of its critical elements as proof of concept. The main activities of this work included pilot scale evaluation of the arc behaviour in the presence of dry steam, modelling of the temperature distribution within the reactor and explosibility studies on three different coal dust samples. Keywords: DC arc plasma gasifier, explosibility index, lower explosion limit, minimum ignition energy

Jan 1, 2020

By R. Simon, P. Pagé, L. Li, P. Yang

The Mathews-Potvin stability method is widely used in the Canadian mining industry as a starting point to determine the maximum dimensions of mine stopes. However, it cannot be applied to inclined (more frequently encountered) mine stopes without conducting numerical modelling to obtain the stress factor A, defined as a function of the ratio of unconfined compressive strength of intact rock to the induced principal stress on the exposed stope walls. The need to conduct numerical modelling significantly limits the application of the Mathews-Potvin method. In addition, given its empirical nature and main application for preliminary design, it is deemed undesirable to conduct numerical modelling, especially elaborate modelling. Alternatively, theoretical methods can provide a much simpler and quicker way to estimate stresses around stopes and the corresponding stress factors. Over the years, a large number of studies have been conducted to estimate stresses around openings excavated with various crosssections. However, theoretical or graphical solutions remain unavailable for mine stopes that typically consist of horizontal floor and roof, and two parallel inclined walls (hangingwall and footwall). To remedy this situation, a series of numerical simulations is first performed for openings with vertical and inclined walls, including typical stopes commonly encountered in underground mines. A group of empirical solutions is then formulated to estimate the induced principal stresses at the roof centre and mid-height of the stope walls. The validity and predictability of the proposed solution have been verified using additional numerical simulations. The proposed solution can thus be used to calculate stresses and the resultant stress factors A around typical mine stopes with any inclination angle and height to width ratio, under any in-situ stress state, without conducting numerical modelling.

Aug 1, 2021

By Y. F. Bulgakov, Y. V. Melnikova, V. S. Zakharov

A new technology of atmosphere in inertization of fire section with the help of gazeous nitrogen is presented in the report. This technology is based on membrane air subdivision into two streams, concentrated with nitrogen (up to 99%) and with oxygen correspondently with subsequent giving them into the place of fire. This technology belongs to environmentally friendly ones and it has a great number of technical, mobile and economic advantages comparing with the rest of well-known methods of fire extinguishing. This technology application in Ukrainian coal mines allowed to reduce the member of isolated places of fire at the expense of their extinguishing efficiency.

Jan 1, 2003

By Mike de Wit

Of the approximately 6,500 kimberlites known to date, less than 3% are diamondiferous and less than half of those are economically viable. Admittedly, this is a global figure and varies from area to area much depending on geological, logistical, and political circumstances. The number of diamond-bearing kimberlites is an important geobarometer, and an age-frequency profile has been compiled in order to identify diamond metallogenic epochs and provinces. Four primary diamond clusters have been recognized: Siberia (332-370Ma), Kaapvaal South(114-144Ma), Kaapvaal Southwest(84-95Ma), and Slave (52-55Ma). In addition, three secondary clusters are the Kaapvaal Central (S06-S38Ma), the Man Craton (139-lS3Ma) and the Kasai Craton (120-130Ma). The Kaapvaal is the only area where kimberlites with diamonds were discovered between 1870 and 1925, except for the Prairie Creek discovery in North America in 1906 and Colossus in Zimbabwe in 1907. Between 1906 and 1940 no major diamondiferous kimberlites were discovered, but many of Africa's alluvial deposits were found and exploited in that period. Advances in scientific prospecting in the 1940's rapidly accelerated the discovery rate that peaked in the 1990's; 39 diamondiferous occurrences were found in the 1980's, of which 8 became mines and 5 are in feasibility, and nearly 450ha of kimberlite was added to the global resource base. Despite the accelerated exploration expenditure, the last decade (e.g. 2000-2009) has been the leanest since the 1940's. The most important reason for this decline in exploration success is that any undiscovered deposits are largely buried by younger cover. Understanding complex and geophysical noisy basement geology, as well as decomposition of path-finder minerals are major challenges to further exploration success. Major investments in basic geological expertise and field research will have to be made in order to secure future diamond resources. Integrated geophysical studies, geochemistry diamond forensics, and improved imaging of Earth's upper mantle are perhaps foremost in this requirement, but the costs of these activities are such that government support will be required if countries are to sustain their diamond mining industry.

Jan 1, 2010

The key aspects of process metallurgy that distinguish platinum group metal (PGM) concentrate smelting from that of other base metal sulphide concentrates are presented. These differences include considerably higher input chrome and magnesia contents that directly raise the slag liquidus temperature and have the potential to increase accumulations of refractory spinels. Most importantly, the higher processing temperature required for PGM smelting, and the resulting very high matte superheat lead to considerably more onerous smelting conditions than those typical of other smelting operations. This has presented challenges to furnace design and integrity, especially when coupled with the progressive intensification of smelting, involving doubling, and then redoubling, of furnace power input over the past 20 years. These power increases have been enabled by increasingly more advanced furnace cooling and structural technologies. Key technologies include strong constant-force spring-loaded bindings acting in three dimensions to minimize infiltration of superheated matte into brick joints, and robust well-cooled tapholes for reliably tapping the superheated matte. The result has been substantially improved productivity, and reduced smelting capital cost outlay per unit of production. A significant challenge that was not anticipated, presented itself in the form of insidious corrosion of the furnace lining, and especially high-intensity copper cooling elements. Investigation of corrosion in related industries eventually identified 'chloride-accelerated sulphidation', and this term has been retained as it generically describes the most pertinent aspects of the accelerated low-temperature wear of copper coolers observed in PGM smelting. In addition to discussing the corrosion mechanism, this paper describes a number of solutions that were developed jointly by Anglo American Platinum and Hatch to address the copper corrosion problem. First, new monitoring technologies allowed furnaces to be operated more safely for a longer period of time. Second, a system for replacing corroded coolers from outside the furnace during a fast 'hot' shutdown minimized the impact on furnace operating factor and hearth life. Finally, a corrosion-resistant graphite-protected cooler design significantly improved furnace campaign life, and heralds a more lasting solution to cooler corrosion in PGM furnaces.

Jan 1, 2012

By M. R. Anderton

"A hierarchical four-character code designed for geological and allied data may be used to log exploration drill-holes and store the information on magnetic media. The code is intended for use in semi-free format and permits the collection of as much, or as little, data as the geologist may require for the purpose in hand. A method of data storage by variable length records is discussed.Information may be retrieved by means of a simple enquiry language. Optional output facilities could allow the retrieval of data in a form suitable for direct input to a contouring package. The enquiry parameters and interrogation program can thus provide the interface between the data bank and associated application systems."

Jan 1, 2014

By R. Weber

Methane explosions in underground coal mines are a major concern across the mining industry. After the Pike River disaster, Arnot Coal became even more aware of the explosion risk. To determine whether Arnot has adequate precautions against a methane explosion, such as the one that led to the Pike River disaster, a literature survey covering the causes of the incident and what preventative measures should have been in place was conducted. Many different methane explosion prevention methods were evaluated, as well as codes of practice. Based on the findings, Arnot?s measures to prevent conditions favourable for a methane explosion were evaluated.

Jan 1, 2014

By A. J. C. Paterson

High density slurry and paste tailings systems offer significant environmental benefits primarily related to reduced water consumption. However, these potential advantages need to be evaluated on a project-by-project basis. The successful design of a thickened or paste tailings system requires that the system is designed to accommodate the effect of the high density slurry on pumps, pipelines and the overall system operation. The transport system must be designed as an integrated unit and the interaction of all the components need to be considered. The transport system includes the slurry preparation plant, the pump station and the pipeline. This paper assesses the impact of increasing the slurry density in a platinum tailings system from conventional densities to thickened and paste tailings densities. As slurry density and rheology increase, there is a sharp increase in energy consumption for the additional water savings and this additional cost needs to be considered. A case study shows that there is a considerable benefit in increasing densities to the point at which tailings can be still be deposited in the standard manner. For existing systems, increasing density can result in an increased capacity at a marginal power cost, provided that the slurry is not too viscous. For a new system, a smaller pump and pipeline can result in lower capital costs and a marginally higher energy cost, if the optimum density is selected. Keywords: tailings, paste, pumping, slurry

Jan 1, 2004

By S. F. Böde, K. Böde

This paper focuses on developing a comprehensive and pragmatic information technology (IT) strategy for low-margin construction activities. This forms part of the realignment of the general business strategy, and refocusing the operational model. The main elements of the IT strategy formation are analysis of the current IT environment in terms of software and hardware, carrying out a gap analysis, and developing individual functional digitalisation strategies in construction execution based on Building Information Modelling (BIM), business administration processes, communication, business intelligence (BI) and reporting, and data security. Further, substantial emphasis is given to the sustainable strategy implementation in terms of hardware and software readjustments, their integration, user training, and defining the way forward.

Sep 1, 2021

By M. S. Shishvan, J. R. van Duijvenbode, L. M. Cloete, M. W. N. Buxton

Geochemical and mineralogical datasets from Tropicana Gold Mine, Australia, have been used to define ore fingerprints. VNIR/SWIR spectral data were represented by four normalised wavelength regions and were clustered to form spectral classes. Sequentially, these spectral class proportions within a block and collocated XRF data were clustered to form material types (fingerprints). The material types were related to an Equotip-BWi correlation. These correlations can be used to extrapolate a hardness signature and generate a BWi proxy for different blocks. The combined fingerprints and BWi proxy can assist as a tool for enhancing the prediction of comminution behaviour. They can explain specific domain-related hardness variations. For example, one material type could be separated into a softer (~15-18 kWh/t), and harder (>20 kWh/t) material blend. This was accomplished using the commonly overlooked VNIR region at 605 nm. This outcome has significance for blending strategies.

Sep 1, 2021

By B. Ceki, A. Mabentsela

The BCL furnace is scheduled to restart operations after being placed on care and maintenance in 2016 due to depressed nickel prices. The decision to start operations after such a stoppage ought to be led by a techno-economic evaluation of process options to make operations more resilient. For BCL, the decision lies between using the existing flash-smelting furnace (FSF) or a top-submerged lance (TSL) furnace. Available studies show that the FSF combined with other converting technologies is cheaper to operate; however, such studies are based on flowsheet simulation results of single copper concentrates and therefore do not provide a full scope of practical capabilities based on smelter operator skills. Using a t-test on normalized prior operational data from three Cu FSF and two Cu TSL, it was found that the only statistical differences between the operating costs of the FSF and TSL technologies are in the coal use for heating the feed blow and number of rebuilds: the FSF consumes coal to heat the feed blow and the TSL requires 2.4 rebuilds during a course of a single FSF campaign. A summative operating cost comparison over the existing BCL FSF 11-year life shows that BCL can decrease operational costs by some BWP 55.5 million if the operation were to change to the newer TSL technology. The savings derive from reduced coal use, which is normally associated with heating the blow when using the FSF. Despite the TSL carrying added costs of 2.4 rebuilds during a life time of one FSF furnace campaign, the cost associated with the TSL rebuilds of approximately BWP 1.3 million is minimal compared with the overall operational expenditure decrease that BCL will incur on using the TSL technology. In terms of the technology, BCL can have higher Ni–Cu recoveries at lower operational costs by elimination of Ni–Cu losses and eliminating the slag-cleaning furnace by converting to a TSL furnace.

Jul 10, 2024

By G. L. Smith, B. Genc, V. Morar, U. Govender

This paper presents a novel holistic healthy human framework for C-suite executives and senior leaders in the minerals industry. The value-add of the framework centres around the integration of inner holistic health and interpersonal holistic health to support and enhance environment, social, and governance transformation, with a focus on the social enterprise. The framework unpacks key components of holistic health and their interlinkages to environment, social, governance, and stakeholder engagement. Insights were gleaned from interviews with 10 C-suite executives, each with over twenty years of experience in mining or business leadership. By applying the holistic healthy human framework, industry leaders can strengthen the social licence to operate and positively transform the industry's public image. Broader application to other sectors is underway.

Oct 2, 2025

By J. Zwartendyk, A. Azis

"Every nation must decide how it should exploit its mineral resources so as to contribute most to its national objectives. It is argued that the present value of the future corporate income tax flow derived from mineral exploitation may serve as a useful indicator in moving toward a taxation policy that would contribute optimally toward the greatest public benefit.The future stream of corporate income taxes depends largely on the mineral endowment, consisting of deposits now being mined, known unmined deposits, and unknown deposits.Unknown deposits may be estimated by geological inference. Both known and unknown deposits can be categorized according to grade and size, and divided into economic and uneconomic deposits on the basis of certain prices, costs, rate of return and taxation levels.Computer simulations can be run of discounted cash flow models at various taxation levels to show the impact of taxation changes on future tax revenues."

Jan 1, 2014

By A. Lebedev

Application of dynamic simulation for a base metal processing plant is discussed. The plant receives ore of variable quality from two pits and blending had to be applied to maximise recovery. The plant employs multiple stage crushing, screening, dense media separation, two-stage milling, flotation and further filtration. Stockpiles and bunkers are used in the plant to cater for breakdowns and operating delays, the latter being appropriately incorporated in the model. A detail dynamic simulation model was constructed from the rock face to the filtration plant to assist the plant design, notably with definition of the ore blending method, sizing storage capacity and in-plant conveyors. The plant model was broken down to capital equipment items and various feed types and mass balances were tested to ensure that the production target is met. The dynamic simulation tested the proposed blending method, identified bottlenecks, produced risk profiles for all strategic storage facilities and overall helped minimise the project risks and improve confidence in the plant design. Keywords: Dynamic simulation, ore grade, blending, capacity, risk profile, throughput, utilisation

Jan 1, 2020

By E. K. Mutinda, D. K. Maina, R. M. Kasomo, B. O. Alunda

Assessment of blast fragment size distribution is critical in mining operations because it is the initial step towards mineral extraction. Different empirical models and techniques are available for predicting and investigating the consequences of blasting, one of which is the Kuznetsov Cunningham-Ouchterlony (KCO) model. In this paper we summarize the advances in the empirical models from inception until now, and explore the improvements that have been made so far with particular emphasis is on the most recent KCO model. Utilization of the model and the errors that arise between expected and the actual outcomes are analysed. The results indicate that the KCO model remains useful for predicting the blast fragmentation at limestone mine sites, despite the availability of other advanced prediction models. It is also a valuable instrument for pre-surveying the impact of varying certain parameters of a blast plan.

Mar 1, 2021