Search Documents

It is widely accepted that the type of grinding media has an impact on the grinding chemistry and subsequent flotation behaviour of the sulphide minerals being separated. There are countless laboratory investigations demonstrating that inert grinding media produces more oxidizing pulp potentials, reduced levels of grinding media corrosion products, and superior concentrate grades and valuable metal recoveries. However, taking these results to industrial scale has proved difficult. This paper provides details of the protocol developed and used during a high-chrome grinding media plant trial. It describes the test regime employed to measure changes in pulp chemistry as well as concentrate grades and recoveries to produce a statistically meaningful result. The work also highlighted the need for close cooperation between the metallurgists on site and the researchers conducting the trial. To demonstrate the protocol, data gathered during a plant trail in a PGM concentrate will be presented describing the changes in pulp chemistry and metallurgical response observed.

Jan 1, 2012

By G. L. Smith

As the Platinum mining industry expands in the Eastern Limb of the Bushveld Complex it is increasingly evident that a major constraint to development is a lack of appropriate infrastructure. Of critical concern are water resources and spatial development / infrastructure. This paper identifies the context for infrastructure development in the Eastern Limb and two solutions that have evolved in the areas of water supply and spatial development. INTRODUCTION In an economics context, infrastructure is considered to be the structural elements of an economy which allow for the production of goods and services, without themselves being part of the production process. Despite the lack of a specific definition, infrastructure has largely become understood as to comprise road and rail transport systems, public transport systems, airports, public educational facilities, water supply and water resources, wastewater management, solid waste treatment and disposal, electric power generation and transmission, telecommunications and hazardous waste management systems. Critically it is important to understand that infrastructure not only comprises these physical elements but also the operating procedures, management practices and developmental policies that facilitate the effective utilization and development of the infrastructure in response to societal demand.

Jan 1, 2008

By C. Musingwini

An often overlooked factor in the analysis of mine layouts and schedules is technical operating flexibility (or tactical flexibility), mainly due to its nebulous nature. By glossing over technical operating flexibility the resultant mine layouts and schedules maybe suboptimal. The need to incorporate technical operating flexibility into the analysis and comparison of mine layouts and schedules is increasing in importance. The nature of technical operating flexibility is illustrated, previous work on valuing of operating flexibility reviewed, and a proposal made on how technical operating flexibility can be quantified for tabular reef mines by using a platinum reef deposit as a case study. Once technical operating flexibility has been quantified it becomes possible to explore its incorporation into the analysis of mine layouts and schedules and subsequent optimization processes. This paper is a revised version of a paper presented in the Proceedings of the Second International Platinum Conference, ?Platinum Surges Ahead? in 2006. The work described in this paper is part of a current PhD study at the University of the Witwatersrand. Keywords: mine plans, layouts, schedules, technical operating flexibility/tactical flexibility, ore availability.

Jan 1, 2007

By N September, R Abate

Bateman Modular (previously Van Eck and Lurie) has been building and supplying the mining industry with modular DMS plants for the last 30 years. These DMS modules range in capacity from 1 tph to 200 tph. The most popular unit produced by Bateman Modular over the years has been the 50 tph module. Development In the last 7 years a need has arisen from the industry to provide Modular DMS plants that can treat higher tonnages (150 to 200 tph). The first DMS provided to the mining industry based on the modular concept was a 150 tph DMS Module to MIBA in the DRC. Since then Bateman Modular has provided some 14 Mega DMS modules over the last 7 years with the latest two orders from Debswana (Damtshaa double up project) and Namdeb. Ever since the first Mega Module was supplied Bateman Modular has been improving the Modules. Implementation The modules can be supplied in different configurations so as to improve the overall availability of the plant. Two off 150 tph DMS modules were supplied for a Transhex operation. This allowed the client to still operate one DMS module while maintenance is being performed on the other DMS module. The client also has the option of choosing a single module. Successes The following list of projects provides the base for the success of the Mega Modules.

Jan 1, 2006

By R. V. Ramani, R. Stefanko

"The favorable mining conditions in the United States of America that resulted in the development of the highly productive room and pillar systems are largely disappearing. Increasing mechanization, poorer natural conditions, and greater concern for health, safety and environment gave impetus to the enactment of the Federal Coal Mine Health and Safety Act of 1969. These regulations prescribe more stringent requirements in face ventilation and mine air distribution, necessitating significant changes in existing ventilation systems. Stringent mandatory standards were applied to respirable dust control for the first time, and simultaneous control of both gas and dust has affected the face as well as primary distribution, most notably on haulage entries.The size and complexity of the present-day mining operations, and the need to evaluate various system changes in a limited time, call for scientific methods in mine planning. In this paper, the authors trace the previous applications of computers to mine ventilation planning and discuss the results of their work in applying a ventilation simulator developed at Penn State. The paper includes an analysis of current trends and suggestions for future research and development."

Jan 1, 2014

By W. W. de Graaf, M. J. Ntsekhe

Klipspruit Colliery is experiencing coal losses, which leads to a negative impact on coal production and subsequently loss in revenue. This study aimed to identify the possible causes of coal losses in the No. 4 upper and lower seams. The objectives were to identify potential sources of coal losses through a literature survey, to identify areas where the coal losses occurred, to determine factors affecting coal losses, and to identify the most cost-effective methods to reduce coal losses. Highwall losses, top-of-coal losses, and coal edge losses were identified as the major areas of coal loss at Klipspruit. These losses were mostly attributed to the drilling and blasting practises of the pre-split, interburden waste, and the coal seams. Recommendations include re-visiting the current pre-split design and the tolerances adopted for the interburden and coal seam drilling and blasting design. It is furthermore recommended that Klipspruit implement a continuous improvement plan for the drilling and blasting and refresher training for the blasting crew and operators.

Jun 10, 2024

By Q. P. Campbell

The high final total moisture content of fine coal after mining and processing is one of the major reasons that this resource is not extensively used in subsequent power generation, combustion, or other conversion processes. Some coal products, like export coal, may be subjected to a variety of environmental conditions during transport and storage, such as temperature and humidity. To understand the mechanisms by which moisture is attracted and held on and within fine coal particles, further information is needed regarding the processes occurring at the coal surface. In order to determine the correlation between physical coal properties and its moisture adsorption and desorption characteristics, a series of sorption experiments were conducted on various coal samples under climatically controlled conditions. Equilibrium moisture data was collected while changing the temperature and humidity. This data was correlated to coal properties such as particle size, porosity, maceral composition, and mineral content. All the coals that were studied were medium-rank bituminous coals. It was found that the best predictors for moisture adsorption and desorption were the mineral and inertinite contents. Keywords moisture, adsorption, desorption, fine coal, surface properties.

Nov 1, 2013

High pressure grinding technology has gained further interest in various industries. So far in the mining industry, machines are in operation in diamond mines and iron ore applications. In gold and copper ore processing, test work has been conducted showing considerable operational and process benefits. Similar benefits can be expected from HPGR applications in the platinum industry due to the preferred ore breakage along grain boundaries, thus liberating the PGE particles. This paper will provide an update on the state of high pressure grinding roll technology. Developments in the design of high pressure grinding rolls, for minimized maintenance requirements and availability just as high as conventional mills, will be presented. Plant flow sheets and concepts will be discussed, which allow for a reduction of capital and operating cost in comparison to existing two-stage milling circuits.

Jan 1, 2004

By Rodney Ishak, Merete Tangstad

In the HC FeMn production, better utilisation of coke and electric power is vital for reducing the production costs. The higher manganese oxides in the charge are reduced to MnO in the prereduction zone, where also the Boudouard reaction is active. These gas-solid reactions are to a large extent decisive for the total consumption of both coke and electrical power in ferromanganese production. In the present work formulas for calculating the Degree of prereduction have been developed for industrial practice. It shows that the typical Degree of prereduction is between 10-40%, but it may in good periods be as high as 60%. Statistical analysis has been done in order to find how various operational parameters influence the Degree of prereduction. A few parameters were observed to have an effect on the prereduction. Comilog ore definitely had a positiveinfluence on the prereduction, Comilog sinter and Mamatwan ore probably had a positive influence on the prereduction, all in relation to the average prereduction in the selected periods. Meanwhile, As man ore definitely, % H2O in raw materials and increasing Hd probably, had a negative influence on the prereduction. The findings for these raw materials were very much in coherence with the results of laboratory scale experiments performed, where the CO-reactivity of different ore materials was studied.

Jan 1, 2007

By G. G. le Roux

The purpose of the investigation was to assess various options for increasing the efficiency of the conveyor belt transporting system used at 4 Belt Shaft at Lonmin?s Marikana operations. The reason for the investigation was to prevent the occurrence of a ?bottleneck? at the main ore passes delivering ore to the conveyor belt system, thus creating more fluent operational conditions. The options assessed for increasing the efficiency of the conveyor belt transporting system were: ?Variation of the conveyor speed ?Concurrent tipping from two ore passes on the belt ?Increase the available drive unit power ?Increasing the feed rate from vibratory feeders ?Change in belt width/belt specifications The report shows that the most preferable option to the current situation at 4 Belt, Lonmin, would be the option of concurrent tipping from two ore passes to the belt.

Jan 1, 2008

By R. W. O. Kersten

It was decided that Anglovaal should conduct a course on technical computing to help middle and upper mine management (40 years and older) to use computers. Background This decision was taken against the background of perception that various people have of computers and computer-related processes. People of the older generation Book review Rock mechanics for underground mining, by RH.G. Brady and E. T. Brown. London, George AlIen & Unwin, 1985. 527 pp. Reviewer: S. Budavari Mine safety awards The mining challenge of our time is the maintenance of the very highest safety standards, says a Chamber of Mines Executive. Haulage in surface mines An international symposium on 'Of-highway Haulage in Surface Mines' is to be held in Edmonton, Canada, from 15th to 17th May, 1989.

Jan 1, 1988

By T. Markus, K. Hilpert

Discharge vessels of advanced light sources are made of translucent polycrystalline Al2O3(PCA).These tubes contain salt mixtures, which essentially consist of metal halides. The salt mixture is present as a melt at the coldest spot of the vessel under operating conditions and vaporizes partly. The temperatures of the coldest spot range between 1200 K and 1300 K, depending on the lamp performance. The maximum wall temperatures range up to 1500 K and for special purposes up to1700 K. Important constituents of the melt are alkali halides AX (A = Na, Cs, X= Br, I) and rare earth metal halides LnX3(Ln = Dy, Ho, Tm). Severe corrosion attack on the wall material is observed in the PCA discharge vessels. The aim of this work is to elucidate the corrosion mechanism. Annealing experiments under well defined temperatures were carried out in order to understand the complex chemical corrosion processes. Two different annealing vessels were used, one for experiments under isothermal conditions with a temperature of 1473 K and one for experiments with a linear temperature gradient from 1450 K to 1600 K. The vessels were filled with salt mixtures of different compositions and annealed for 1000 h. The corrosion attack was characterised by XRD, analytical electron microscopy, high temperature mass spectrometry, and chemical analysis of the salt melts. The results of our investigations show that the corrosion attack is caused by vapour species and by the salt melt. The most severe corrosion is observed in vessels filled with mixtures of alkali halides and rare earth metal halides. No corrosion of the alumina is practically observed if pure alkali halides or pure rare earth metal halides are present in the annealing vessel. Keywords: thermodynamic, corrosion, lamps, metal halide salt

Jan 1, 2004

By D. F. Malan

This paper describes the development and implementation of amine-wide continuous stability monitoring system at the Declines Section, Anglo Platinum Union JV. The Declines Section at Union JV experienced a number of large panel collapses during 2005 and 2006. As well as posing a major safety risk, the panel collapses had a major effect on production since the Declines Section is a semi-mechanized operation. The collapses would often extend into the mechanized strike roadways, resulting in a loss of access to both current and future production faces. The collapses have been largely overcome owing to a change in support design and the implementation of a mine-wide stability monitoring programme. This paper describes the precursors to collapses, which were identified using continuous closure measurements and the remedial measures taken. It also outlines the design and introduction of a robust and reliable monitoring tool, which is now used on a mine-wide basis to provide early warning of large-scale collapses.

Jan 1, 2010

By D. McCarthy

Contract is a PC-based software program designed to satisfy the main features that have been identified to be lacking from cost estimation systems currently in place in the Australian coal industry. Contract was developed in conjunction with an Australian contracting company to refine the existing core structure used by the company for project evaluation. The key feature of Contract is the availability of analysis functions to explore multiple options within a contract project by altering identified variables. The ability to update project files has been incorporated into Contract to ensure that it is user-friendly and relatively simple to use. Lists of mining equipment and consumables are stored in MS ACCESS database files, along with the supplier details for each item. Each time a project is initiated there is a dynamic link to the database files and the most recent current information is retrieved and linked with the project. Contract provides an option to calculate the changes in metre unit cost as a function of the average development cost. Keywords: Contracting, cost estimation, sensitivity analysis.

Jan 1, 2003

By I. J. Barker

This paper argues that the scale up of furnaces and the supply of electricity are going to be two major issues that will affect the ferro-alloy industry in the near future, and that economic factors will drive this development. The most common type of furnace for producing ferroalloys at present is the submerged-arc furnace with three electrodes, fed from a three-phase AC electrical supply. The scale up of this technology has now reached a fundamental constraint, which is caused by the electrical reactance of the secondary circuit. If the economy of any further scale up is to be achieved in the future then a different technology will have to be used. The supply of electrical power in future is likely to become amore complex issue than it is at present. Existing submerged-arc furnaces tend to run at fairly steady loads, but the ability to swing the load under demand-side management may offer advantages, and may allow a furnace to obtain cheaper power from the organizations that supply this power. This will have to be counterbalanced against the nuisance factors incurred by having a varying load in the operation of the furnace. Various options are therefore discussed in this paper. The possibility of scale up of Søderberg electrodes is discussed, as well as the use of DC power and multiple electrodes. Some of the issues with load swinging are also examined. A particular scenario is also briefly presented to show that considerable further scale up of ferro-alloy furnaces is still possible.

Jan 1, 2011

By A. W. Dougall, T. M. Mmola

"SynopsisThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs) – which are those areas of performance that are reflected explicitly or implicitly in the vision and strategies of an organization and reflect the critical success factors of the organization. This paper is a review of key performance areas in the southern African mining delivery environment. The KPAs discussed in this paper have been identified by comparing KPAs of the several mining houses engaged in surface mining operations in southern Africa and then extracting those KPAs that are common to most of them. Although the authors support the view that each organization should develop KPAs to specifically fit its needs, the study reveals that five KPAs – safety and health, costs, product quality, fleet management, and delivery should form a default list that covers the key areas that any organization should consider when choosing KPAs. KPIs are those subsets of KPAs that we measure in order to manage KPAs.IntroductionThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs), which are ‘those areas of performance that are reflected explicitly or implicitly in the vision and strategies of the organization’ (Barker, 1997). The terms KPA and KPI (key performance indicator) are often used interchangeably – whether correctly or erroneously is debatable. KPIs are ‘quantifiable measurements, agreed to beforehand, that reflect the critical success factors of an organization’ (O’Neill, 2007). Each KPA probably has multiple KPIs associated with it."

Jan 1, 2015

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

By O. F. Ochonogor

Laser metal deposition (LMD) is an additive manufacturing technique whereby a stream of metal powder is consolidated by a focused laser beam on the surface of a substrate or engineering component. The interaction zone between the laser beam and powder particles is scanned superficially, generating tracks of deposited material. The tracks are overlapped in a deposition strategy in accordance with slices of a CAD model. Successive layers of material are built up to fabricate a near net shape part. In this work, the technique is used to fabricate metal matrix composites (MMCs) by using an elementally blended feedstock combining metal and ceramic powders in the melt pool, which melt and solidify to create the required morphology. Ti6Al4V + TiC MMCs were produced with 10, 20, and 30 vol.% reinforcing ceramic, and Zr + TiC MMCs were fabricated with 10, 20, and 30 vol.% TiC. The deposited thin walls were analysed using optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and indentation testing. In both systems, the analysis revealed the presence of partially melted TiC particles embedded in the metal matrix along with fine dendrites of re-solidified ceramic. The dendritic structures in the Ti-based composites were confirmed as TiC, whereas in the Zr-based composite the Zr metal reacts with theTiC to form ZrC, leaving Ti in solid solution. Both the MMCs show an increase in microhardness with increasing ceramic (carbide)content, reaching a peak HV0.1 value of 500 in the Zr- based MMC and HV0.1 of 550 in the Ti based MMC.

Jan 1, 2012

Bateman Engineering managed the establishment of a second diamond treatment plant at the Letseng Mine in the Mokhotlong District of northern Lesotho, about 100 km from the town of Buthe Buthe. Letseng Diamonds Proprietary Limited, is owned 70 % by Gem Diamonds and 30 % by the Government of the Kingdom of Lesotho. The second plant, which commenced construction in late 2006, doubled Letseng Mines' hard rock processing capacity from 2.6 million t/yr to 5.2 million t/yr, making it the worlds' seventh largest diamond mine by throughput. Bateman Engineering provided the engineering design, procurement and construction management of the new plant.

Jan 1, 2010

By O. T. Konina, V. A. Masloboev, A. V. Svetlov, E. A. Krasavtseva, D. V. Makarov, A. A. Goryachev

Dusting phenomena have been examined at the tailings storage facility of Apatit JSC Kirovsk, a mining operation located in the far north of the Russian Federation. The material composition of the tailings was identified. Existing dust suppression methods were examined. Field observations were undertaken and official data was obtained from the Murmansk Administration for Hydrometeorology and Environmental Monitoring, and analysed. A database was built for forecasting dusting according to critical scenarios in order to estimate the peak MPCs of suspended solids in the atmospheric air. Mitigation measures were formulated and recommended to the mining operation. Keywords: Mineral dust particles, apatite-nepheline ore concentration tailings, suspended solids MPC, climate change

Jan 1, 2020