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By E. Garab, M. Pillalamarry, E. Develo

"Recent geological exploration at Rosh Pinah mine revealed that the mine’s major production is shifting towards the western orefield, which will increase the demand for air flow to be supplied to this area. A snapshot of the ventilation survey carried out in December 2014 at the western orefield drill drive B (WOF-DDRB) showed that the air flow was well below the required standards. In order to improve the existing conditions, possible options were considered and simulated using Ventsim™ software.The best option found was to replace the existing western orefield fans with the larger fans from the inactive southern orefield workings, to increase the air flow in the DDRB district. Simulation showed that as much as 20 m3/s of air can be received at the working faces of WOF 30, compared to the previously received amount of 1.37 m3/s. The economic analysis indicated that the above option can reduce the ventilation cost by N$1.9 million annually. It was also noticed that after implementing this option together with other projects, the ventilation conditions in the mine were greatly improved and currently give no cause for concern. IntroductionA good mine ventilation system should be capable of providing adequate quantity and quality of air to all working faces, and is critical to the occupational health, safety, and comfort of underground employees (Luxbacher and Ramani, 1977; Exikis and Kapageridis, 2006). No ventilation system can remain adequate indefinitely; as the mine workings are extended, the ventilation characteristics such as system pressures, air volumes, leakages, and airway resistances change considerably. Continuous improvement of the ventilation system is needed to ensure compliance with health and safety regulations (Lovejoy, 2010). It also ensures that the right quality and quantity of air is delivered to all the necessary areas at the lowest possible cost. This can be achieved by identifying inefficient airways and poorly ventilated areas in the mine and planning how best to upgrade them.The latest geological exploration shows that the focus of production at Rosh Pinah mine is shifting towards the western orefield (WOF). As mining progressed, the working areas have advanced away from the main fans, which increased the resistance to air flow drastically and resulted in increasing demands being imposed on the main fan in order to supply an adequate air flow. This process also created more leakage paths between the fan and the working areas, which has caused the air to short-circuit before it can reach the faces. Consequently, a much larger quantity of air has to be circulated by the fan so that the stipulated quantity reaches the face, which increases operating costs (Singh et al., 2004)."

Jan 1, 2016

By S. Liaghat, J. Rosenkranz, P. Semsari Parapari, S. Chehreh Chelgani, A. Tohry

It is commonly accepted that the energy consumption for comminution within mineral processing is responsible for around 3% of the global electrical energy usage. However, it was clearly noted that inside mills, less than 1% of this energy efficiency is actually consumed for particle size reduction. Therefore, monitoring of grinding parameters and modelling of product particle size distribution (e.g. characterised by the 80% passing size P80) play an essential role in operating costs of a mineral processing plant. Several empirical models have been introduced for the prediction of the P80. Since in the industrial scale usually a few numbers of grinding variables are monitored, these models cannot identically be used in plants. In addition, these empirical models do not always indicate the magnitude of correlations between milling variables. This study proposes to introduce the Hilbert-Schmidt independence criterion (HSIC) as an intelligent model for exploring linear and nonlinear relationships between grinding variables and P80 for an industrial scale data assessment. HSIC can rank variables based on their importance and help to select the most effective one for the generation of predictive models. HSIC modelling through various monitored grinding variables (ball charge, feed input rate, F80, power draw and work index) of an industrial plant indicated that F80 as a feed property has the highest effect on P80 of the ball mill products. Modelling results highlighted that the P80 can be accurately predicted, based on effective variables by using a HSIC model. These outcomes showed that HSIC as a powerful modelling tool can assess the relationships between monitored grinding parameters, select the most effective grinding parameters and satisfactorily predict the P80. Keywords: Product particle size, variable importance measurement, Hilbert-Schmidt independence criterion, mill charge

Jan 1, 2020

By T. M. Louw, L. Auret, S. M. Bradshaw, F. F. Noelle

Modern industrial processes undergo frequent process state shifts due to changes in demand, feedstock or maintenance operations. Multimodal continuous process monitoring is therefore required for effective plant operation. Steady state analysis is a key component in effective multimodal monitoring. Various issues still remain in determining the starting and ending times of transition states. High dimensionality of process data is a characteristic that makes it difficult to select variables to consider when conducting steady state analysis. In order to address these problems, steady state detection on the principal component space is proposed. First, data undergoes principle component analysis to reduce dimensionality, then existing multivariate steady state detection algorithms are applied on the principle component scores. A novel algorithm, threshold PCA-SSD, is proposed and compared to an existing technique for steady state detection. The algorithms are investigated on high dimensional synthetic data Keywords: Multimode process, steady state detection, principle component analysis

Jan 1, 2020

By D. Minson, G. Lindner, S. Miskovic

Thickening is an essential process in the mining industry and currently one of the most costeffective technologies for recovering water from tailings streams. Improved performance of thickeners can lead to significant energy savings, and increased recovery of water close to the mill. Its performance is directly affected by the rheological properties of slurry at the raking zone. To further understand the dynamics of slurry inside thickeners, a multiphase particle-in-cell method (MP-PIC), is used to investigate its behaviour on a sliding channel. Parameters like particle-size distribution (PSD), rheological properties, and domain discretisation were benchmarked to study its influence on highly dense flows. The slurry concentration by weight of the samples ranged between 60 to 70% of solids by mass, under which conditions it is known to behave like a non-newtonian fluid. An experimental flume, 0.2 m wide and 2 m long, was used for validation under different angles and slurry composition. Visual analysis of the slurry height and shape, as well as velocity measurements, were compared with numerical data. The preliminary results show the ability of MP-PIC method to represent different types of highly dense flows, while still being computationally affordable and practical for industrial use. Keywords: High density thickener, CFD, MP-PIC, multiphase-flow

Jan 1, 2020

By K. Esmeli, A. Ozkan

The enhancement of shear flocculation of a galena suspension by ultrasound in the presence of sodium isopropyl xanthate and potassium ethyl xanthate was investigated by studying the effects of surfactant concentration on flocculation efficiency, contact angle, and zeta potential. Strong flocculation was obtained under alkaline conditions (pH > 9) and a high ultrasound power level (150 W). Although the ultrasonic treatment increased the negativity of the zeta potential of the galena particles, this did not decrease the flocculation efficiency, thereby showing that the hydrophobic interactions between the particle were stronger than the electrical double-layer repulsion resulting from xanthate adsorption. The findings indicate that the ultrasonic treatment promoted the adsorption of surfactants onto the mineral surfaces.

Jul 5, 2023

By G. J. McTeer, D. J. Rioux

Teck Metals Ltd operates an integrated zinc-lead complex at Trail, British Columbia, Canada. Since 1997, KIVCETTM flash smelting technology has been utilized for the treatment of zinc plant residues and lead concentrates. Trail Operations’ furnace uses four water-cooled jackets for bullion tapping. This paper provides an overview of KIVCET bullion tapping for the past 16 years, and discusses successes and challenges encountered with respect to operations, training, and monitoring.

Jan 1, 2014

By D. G. Krige

The problem of a realistic investment analysis for a new mining venture that sells its products on the international metal markets IS studied against the background factors, firstly, of different inflation rates between the countries hosting the mines and those. hosting the metal markets; and, secondly, of the changing pattern of currency exchange rates between such countries. The purchasing-power parity theory is used to establish a pattern of relationship between these two factors, and to develop a more logical approach to the long-term forecasting of metal prices in the currency of the country in which the mine is situated.

Jan 1, 1979

By H. Matsuoka, M. Kawata, K. Mitsuhashi, C. Tokoro, T. Kato

Copper sulfide minerals generally have high floatability, but their floatability decreases when surfaces are oxidised under some conditions. Sodium hydrosulfide, NaHS, is known both as an activator and as a depressant for copper minerals. NaHS at low concentrations activates copper oxides by sulfurising surfaces, but at high concentrations depresses copper sulfides by interfering with the adsorption of collectors. In this paper, we applied NaHS to activate oxidised chalcocite and bornite and focused on the conditions of NaHS treatments such as dosages and pH, and the effect of these conditions on the floatability of those minerals. The pure minerals treated with NaHS were analysed using zeta potential analyser and X-ray photoelectron spectroscopy. Analyses indicated that the reactions of NaHS and the products on the mineral surfaces after the reactions (i.e. oxidation, pH change) depended on whether NaHS reacted with copper or iron, and the reactions between NaHS and iron depend on NaHS concentration and pH. Flotation tests using a small column cell were performed with a single pure mineral, and using a Denver-type flotation machine with a copper sulfide ore. The results of each flotation test were utilised to clarify the floatability. The relation between flotation behaviours and analysis results were also discussed. Keywords: Chalcocite, bornite, NaHS activation, flotation, floatability

Jan 1, 2020

By I. V. Filippova, Y. Foucaud, M. Badawi, L. O. Filippov, S. Lebègue

To optimize the flotation of Ca-minerals, their separation contrasts were investigated by coupling experimental and theoretical techniques. We showed that they mainly rely on structural properties such as the Ca-Ca distance on their exposed surfaces but also on the ability to control the intermolecular interactions. An optimized composition of the carboxylic collector by calculating the collector-mineral and the intermolecular interactions was developed. Blending the saturated acids and non-ionic molecules with a fatty acid collector significantly increases the flotation selectivity between scheelite (CaWO4) and fluorite (CaF2). The theoretical results were validated by experimentally improving the separation contrast between Ca-minerals. After the tests of several depressants and collectors, the best depression of gangue Ca-minerals (fluorite, apatite and vezuvianite) was found by combining sodium silicate and sodium carbonate. Keywords: Ca Minerals, Fluorite, Scheelite, Carboxylic acids, Unsaturated Acid, Fatty acids

Jan 1, 2020

By D. Yu Pleev, V. G. Krivolapov

Mines of Southern Kuzbass working out, basically, coal formations of flat seams. Seams, as a rule, are inclined to self-ignition. Detection at early stages of the centers of endogenous underground fires has great value for safe conducting mountain works. One of methods of detection of an early stage of underground fires in the worked out space is the method of superficial radon survey. In the report the method is de-scribed and examples of superficial radon survey on concrete layers are given.

Jan 1, 2003

By I. Wigden

This paper discusses system integration and installation of High-Tec systems in underground mines. ABB has the capability to be a System Integrator and co-operates with partners in different areas of technology. Today it is difficult to find one Company that is responsible for the complete Automation System. The design of the system is also dependent on the caving procedure that is currently being used in mines. Most of the engineering must be done during the feasibility study and the design phase. Any mistakes made during these phases will be costly to rectify in the commissioning phase. The paper will also include a presentation of the benefit of using Automation in an Underground Mine, and the importance of integration with the people component. Most of the experience and discussions in this paper are from different technologies that have been developed in Scandinavia and adopted from LKAB in Kiruna. The author of this paper was responsible for the Automation projects in Kiruna Mine during1994 - 1999. These projects include: • Broadband communication of data, audio and compressed video in one data stream. • Control System for Haulage -1045m • Automation of Load Haulage and Dumping machines (LHD) • Control of Production Drilling Rigs from a Central Control Room.

Sep 1, 2001

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

By D Olivier

De Beers' Finsch Mine is situated in the Northern Cape province, 170 km northwest of Kimberley. The concentrator facility, designed and constructed by Bateman Engineering, was commissioned in 1967 and upgraded in 1979 using diamond liberation and extraction technology available at the time of design. Since then significant advances in diamond processing and technology have been made and these -have been incorporated into the new main treatment plant and recovery plant flowsheets, making diamond liberation and recovery from the Pre-1979 dumps a viable economic option at Finsch."

Jan 1, 2010

By T. M. Chagwedera, A. E. Lewis, J. Chivavava

Eutectic freeze crystallisation is a novel separation technique that can be applied to treat brine solutions such as reverse osmosis retentates, which are often a mixture of different inorganic salts. The treatment of calcium sulphate-rich brine solutions through eutectic freeze crystallisation has resulted in gypsum scale formation on the walls of the crystallisers and ancillary equipment. In order to prevent gypsum scaling on equipment surfaces, it is essential to understand the mechanism of gypsum scaling on cold surfaces. This paper focused on the interaction between gypsum crystallisation in the bulk solution and scaling on the crystalliser walls in the presence of gypsum seeds. A cooled, U-shaped stainless-steel tube suspended in the saturated solution was employed as the scaling surface. Preliminary results showed that the scale layer was predominantly composed of needle-type and hexagonal prismatic crystals. The rate of scale deposition was highest during the first 24 hours, thereafter it decreased. A thin scale layer was observed to have coated the tube within the first hour of the experiment. Seeding, using reagent grade gypsum crystals, was effective in reducing scale layer formation through providing a surface for growth. The highest scale reduction, 81%, was realised at a seed loading of 0.50 g/L. At a high seed loading of 4.01 g/L, the seed material adhered to the tube. Keywords: Gypsum, eutectic freeze crystallization, seeding, scaling, cooling crystallisation

Jan 1, 2020

By Jürgen Antrekowitsch, Harald Osthof, Stefan Steinlechner

"In the case of feasibility assessments or feasibility studies, an important point of discussion is often how to calculate the capital (CAPEX) and operating expenditure (OPEX) of a plant. Generally, there is also the request to know how the CAPEX varies when the size of the plant is increased. Nowadays, many databases give an indication of specific equipment costs in relation to the production rate. These data are based on cost information from equipment suppliers and have to be continuously updated by the owner of the database. The approach presented here is a model which allows sizing of process equipment, for example a leach tank, based on process data in combination with the calculation of mechanical properties. Furthermore, it calculates the CAPEX based on construction material cost and adequate machining surcharges. Thus, a single cost model for a leach tank is adequate for both copper and other hydrometallurgical plants and stays valid with changing construction material prices. To summarize, the advantage of this model is the more versatile approach and thus the flexibility due to the inclusion of design aspects, process and mechanical engineering aspects and an updatable database. The database, which is in regard to material cost and is the basis for the cost estimation, is easily updatable from commonly accessible data. This model thus approaches the procedures of an engineering company when designing a plant and executing a cost calculation. INTRODUCTION Hydrometallurgy nowadays plays an important role in processing of primary and secondary resources. In copper metallurgy, hydrometallurgy accounts for roughly 20 % of worldwide primary production, especially in the case of oxide or low copper-containing ores. Zinc smelters changed their method of production from a pyrometallurgical-dominated concept decades ago to mainly hydrometallurgical routes today. Gold production processes using leaching, especially, have a long history without any development which would not be competitive if not based on hydrometallurgical concepts (Pawlek, 1983; Winnacker-Küchler, 2006)."

Jan 1, 2015

By M. Kumral, S. Li, M. Balci, Z. Shao

Main haulage roads play an important role in the performance of underground mines because of the cost of transportation of the extracted ore, equipment, and workers. During mine development, these roads are designed through manual tools or CAD-based software. However, the optimisation of these roads is still a complex problem due to some constraints such as minimum turning radius and maximum gradient. By utilising Dubins path theory, three elevation cases; namely low, medium and high are defined, considering gradient constraint as well as the minimum turning radius in a three-dimensional space. The shortest path between two points can then be found by the three-dimensional Dubins path algorithm with elevation constraint. As a further step, a three-dimensional Dubins path algorithm with elevation constraint for multiple points is also developed for multi-point cases. The effectiveness of these algorithms is tested through case studies in order to determine the optimal path between different points.

Sep 1, 2021

By D. Hu, J. Xu, N. Liao, C. Wu, J. Ye

The vertical stirring mill’s fine grinding equipment is affected by the operating conditions during the grinding process. The grinding media has a great influence on the energy consumption and particle size distribution. This paper investigates the fine grinding performance of nano-ceramic balls and steel balls of the same weight for magnetite by a wet grinding process in a vertical stirring mill, where 15 mm nano-ceramic balls and 12 mm steel balls are used as grinding media to carry out batch grinding tests. We have observed that the newly qualified particle content of the nano-ceramic balls is higher than steel balls of the same weight at the same specific energy. The reason may be the advantage of a greater surface area and volume filling rate with the nano-ceramic balls. Moreover, the specific energy of nanoceramic balls is less than steel balls of the same weight under the same grinding fineness. In addition, energy efficiency indicates that the nano-ceramic ball has a higher energy efficiency than a steel ball of the same weight. This is due to the light bulk density of nano-ceramic balls. The application of a nanoceramic ball in a vertical stirring mill will improve iron ore grinding performance. Keywords: Steel balls, nano-ceramic balls, vertical stirring mills, fine grinding, particle size distribution, energy consumption

Jan 1, 2020

By F. K. Crundwell

The rate of dissolution of sulphide minerals is frequently interpreted in terms of the passivating behaviour of a layer of material on the surface. This interpretation has driven research to identify and possibly remove this layer from the surface, and thus yield higher rates of dissolution. The identification of such layers has proved difficult, with different researchers claiming different compositions for possible layers. An alternative framework has been pursued by the author and co-workers, who have argued that the rate of dissolution is governed by the electronic structure of the minerals which give rise to their semiconducting properties. Researchers sceptical of this approach have argued that semiconducting properties are only important in highly pure substances. In this paper, we review the electronic and semiconducting properties and discuss how they impact dissolution behaviour. These properties affect their colour and dissolution properties even though the minerals are not high purity substances. Keywords: Dissolution, leaching, passivation, semiconductor, chalcopyrite

Jan 1, 2020

By K. Cole, D. Mesa, P. R. Brito-Parada, M. R. van Heerden

Turbulence in stirred tank flotation vessels determines the bulk transport of particles and has an important role in particle-bubble collisions necessary for attachment. Positron emission particle tracking (PEPT) produces quantitative measurements of the kinematic motion of different particle classes inside flotation vessels. This paper presents flow profiles of the vessel, residence time distributions, flow profiles through the mesh and macroturbulent kinetic energy distributions as experienced by valuable (hydrophobic) mineral particles in a laboratory scale flotation vessel. The results highlight the impact of the rotor-stator design and a retrofit mesh modification at the upper part of the vessel which improve recovery by decreasing turbulence in the quiescent zone and at the interface. Keywords: Flotation machines, turbulence, PEPT

Jan 1, 2020

By A. Melkumyan, M. Balamurali, J. Zigman

Understanding the contribution of geophysical variables is vital for identifying ore indicator regions. Both magnetometry and gamma-rays are used to identify the geophysical signatures of the rocks. Density is another key variable for tonnage estimation in mining, and needs to be re-estimated in areas of change when a boundary update has been conducted. Modelling these geophysical variables in 3D will enable investigation of the properties of the rocks and improve our understanding of the ore. The Gaussian Process (GP) was previously used to generate 3D spatial models for grade estimation using geochemical assays. This study investigates the influence of the following two factors on the GP-based autonomously generated 3D geophysical models: the resolution of the input data, and the number of nearest samples used in the training process. A case study conducted on a typical Hammersley Ranges iron ore deposit using geophysical logs, including density, collected from the exploration holes, is examined in this paper.

Sep 1, 2021