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By P. G. Henderson, G. C. Thompson

The organization and mechanized colliery management of a large by G. C. THOMPSON, B.Sc. (Min. Eng.) (Witwatersrand), M.B.L. (Member), and P. G. HENDERSON, B.Sc. (Min. Eng.) (Pretoria), M.B.A. (Member). Usutu Collieries Limited, at present the largest single producer of coal in South Africa, supplies Cam den power station. and produces 435 000 tonnes per month by conventional mechanized methods from bord-and-pillar workings in three mines. The thickness of the seams averages 2 metres, and the depth below surface varies from 15 to 150 metres. Each mine depends to a different extent on certain common facilities and services. Two of the mines are located on the same coalfield, and their rationalization would possibly be advantageous. Production policy is one of productivity with flexibility. The double-loader system is widely used, and one section at each mine is worked on single shift. Pillar extraction is practised where possible. In addition to lubrication and inspections, planned maintenance of mining equipment consists of sub-assembly replacements and overhauls. Conveyor and tractor/trailer transport is used underground. but trolley-wire locomotive haulage is being considered. The organization is such that co-ordination is relatively difficult, and certain changes could possibly improve the functioning of the engineering and mining departments. Technical and management training is carried out. Long-term planning will make use of a computer programme and will involve the investigation of other mining methods. Five-year and twelve-month plans are prepared, the planning of coal quality being based on the view that the mine and the power station together constitute a system. Control information systems make use of a remote computer terminal located at the mine. An improved integrated system is being investigated.

Jan 3, 1975

By T. J. Otto, C. Musingwini

"The objective of any mining company is to sustainably maximize the net present value (NPV) throughout the life-of-mine (LOM). The expected NPV over the LOM is calculated based on a mine plan, yet the actual value realized by the mining company depends greatly on the level of intertemporal execution against the mine plan. Consequently, a major key performance indicator (KPI) that is often overlooked in open pit mining, due to a greater focus on temporal KPIs, is the degree of spatial compliance to the mine plan. Such focus sometimes leads to short-term actions being detrimental to long-term plans. In this paper we describe the development and implementation of a spatial mine-to-plan compliance reconciliation approach for an open pit mine. Application to a case study open pit iron ore mine in South Africa indicated a significant improvement in the spatial mine-to-plan compliance, from 69% to 94% over a three-year period from 2014 to 2016. These results indicate that implementation of the proposed spatial mine-to-plan compliance reconciliation approach can contribute positively to improving the level of spatial execution and assists in improving the alignment between short-term, medium-term, and LOM plans.IntroductionThe objective of any mining company is to maximize the net present value (NPV) throughout the life of mine (LOM). However, this objective needs to be fulfilled in a sustainable manner that considers the needs of various stakeholders, including employees, shareholders, and local communities where the mines operate. The expected NPV is calculated using a mine plan as a basis. Mine planning broadly involves identifying a strategy to exploit the mineral resource in a way that maximizes value at an acceptable level of risk throughout the LOM (Tholana and Neingo, 2016).The mine planning process is a well-recognized component in the mining value chain of an open pit mine. Figure 1 reflects the relative position of mine planning within a typical open-pit mining value chain from the mineral resource to the market"

Mar 1, 2019

By K. Hodgson, J. P. M. Hojem, N. G. W. Cook

Already about one-third of South Africa's coal is mined at depths exceeding 100 metres. Almost all this mining is done by the bord and pillar method. Conventional design procedures call for ever larger pillars as depths of workings increase, resulting in the loss of large amounts of coal and reductions in productivity. Barrier pillars are in general use to ensure against large collapses. The presence of these strong pillars would allow a more efficient design of the bord and pillar layout to yield improved extraction ratios by using smaller, yielding, pillars between the bords. Knowledge of the complete load- displacement curves for such pillars is a prerequisite for the design of such a system. A 100-MN, stiff jacking system for measuring the complete load-displacement curves of pillars with cross-sections of up to 2 m X 2 m is described. The jacks are installed in a slot cut across the central plane of symmetry of a pillar, thereby ensuring that the stress distribution in the pillar during a test, especially at its contacts with the roof and floor, is identical to that caused in a similar pillar by convergence across the seam. Preliminary results in the form of complete load-displacement curves for test pillars of about 1.5 metre square section are given.

By H. Rosenberg

Haldor Topsoe A/S has developed its WSA technology to meet the demand in the market for a simple and reliable process that converts sulphurous emissions from off-gasses into high-grade sulphuric acid. With more than 50 references in 25 countries, the WSA technology has proven its ability to generate acid at 98% concentration, efficiently and economically. The wet gas sulphuric acid (WSA) technology treats the furnace off-gas directly from upstream gas cleaning plants. No further drying is required, since the humidity present in the off-gas is used to hydrate the SO3generated in the converter and produce sulphuric acid. The heat generated during the oxidation, hydration and condensation processes is principally reused in the process to preheat the off-gas to the required temperature level, and also to generate high pressure superheated steam for process use. This advantage of steam production, coupled with lower water and power consumption requirements, is particularly important in the African production environment. Having fewer process components than conventional acid plants, the WSA technology is a simple and compact operation, which makes it easier to retrofit into an existing smelter plant. Further, the WSA technology simultaneously offers the possibility to treat multiple gas streams arising within the production facility due to superior flexibility in terms of SO2concentration and turndown ratio.

Jan 1, 2006

By L. Woollacott, R. P. King

Although several models for the carbon-in-pulp (CIP) or carbon-in-leach (CIL) processes have been published, most of these models do not consider in detail the way in which the carbon phase flows on large-scale plants. This paper illustrates the importance of these details if the CIP or CIL process is to be modeled correctly. An appropriate model, based on population-balance techniques, is then derived. Suitable mathematical techniques for the solution of the model equations are also described. Finally, a method for estimating the model parameters for a full-scale plant is described.

Jan 1, 1990

By R. G. B. Pickering, B. Ebner

The hard rock gold and platinum mines in South Africa have seen little development in the technology of mining. Holes are still drilled in the rock—though the latest water hydraulic rockdrills will complete that task in two minutes compared with the eight hours for hand drilling. Charging up is with far safer explosives and with available initiation systems it is no longer necessary to run up the face lighting each fuse. Movement of rock in the stope is predominantly by means of scraper buckets and scraper winches — these were first introduced in the 1920s.Support is still mainly rock, either in sit pillars or backfill, or alternatively wood. Just as themining process has changed very little it is hardly surprising that the productivity of mining is also relatively unchanged. Major efforts have been made to mechanize the mining process. However, most of the narrow reef mines where ‘trackless mechanized mining’ was introduced in the early 1980s have reverted to conventional mining. In the wider reefs mechanized mining is the option of choice, unfortunately most of the gold and platinum mines have very narrow reefs that are not suitable to’ off the shelf’ equipment. The move to introduce room-and-pillar mining into the narrow UG2reefs is at the expense of mining more waste with the reef, fortunately it appears that appropriate waste and reef separation processes are available. Room-and-pillar mining followed by long holedrilling and blasting of a narrow slot of reef out of the pillars currently appears to offer the best of both worlds—maximum reef recovery with minimum waste dilution. All these mining methods are still dependent on blasting to break the rock. The cyclic nature of mining by blasting places severe constraints on the rate of face advance that can be achieved and consequently the utilization of the invested capital. For narrow reef hard rock mining to break out of these constraints and to really make progress in the 21st century it is necessary to follow the lead of the soft rock mining industry and change the technology of mining. In the underground coal mining industry, coal cutting has been proved to be the most cost-effective solution. In narrow reef hard rock mining the future must be based on the development of non-explosive methods of rock breaking that in turn are integrated into continuous mining systems. Non-explosive so that the mining operation can be conducted on a continuous basis, with nodelays for the removal of blasting fumes. Continuous mining also maximizes the return on the capital invested in developing the mine. Rock cutting will define the stope width and that in turn will be designed to minimize waste dilution; it will also minimize damage to the hanging and create a safer environment. Mechanization makes it possible to automate the mining process and further improve safety by positioning the operators in a safer environment. This paper defines the work to evaluate cutting processes carried out by Sandvik TamrockVoest Alpine. The evaluation was in the UG2 and the pyroxenite and norite typical of the Merensky Platinum Reefs. A novel form of mining machine is proposed that will utilize existing technology. Finally the paper describes the interaction between Sandvik Tamrock Voest Alpineand Lonmin Platinum and the initiation of an agreement to develop and trial a prototype hard rock narrow reef mining machine.

Sep 1, 2001

The treatment of gold-plant tailings with ferrous sulphate to remove the cyanide is currently in use, on several gold plants. In some cases there is scope for optimization the process. The present work provides a detailed study of the reaction between cyanide and ferrous sulphate. Optimal conditions for the removal of total cyande required a ph of 5,.5 to 6,5 and an Fe:CN molar ratio of 0,5. Ferrocyanide ion is shown to be unstable In aqueous acidic solution, with rapid oxidation to ferricyanide, (Fe(CN) 6 ), and formation .of Fe(CN)5H2O3- at pH values below 4, The precipitate from the reaction between cyanide and ferrous sulphate consists mainly 01 Insoluble Prussian blue, Fe4[Fe(CNI&!.3,and IS shown to be unstable in the presence of alkaline solution, since it decomposes rapidly at pH values above 7 to form ferrocyanide, (Fe(CN)6 ), in solution and various insoluble iron oxides,

Jan 1, 1992

By O. Korhonen, T. Leskinen

The use of large OK-16 flotation machines at the concentrators of Outokumpu Oy by o. KORHONEN and T. LESKINEN(Visitors) The development ofthe OK-16 flotation machine is described briefly, and an account is given of its use at various concentration plants in Finland. The benefits arising from the use of larger flotation machines are listed, and the technical specification of the OK-16 machine is detailed in an appendix.

Jan 6, 1976

By J. Kitagawa

The principal objectives of a metallurgical test programme for a 'grass roots' mining project are twofold. The first requirement is to establish the metallurgical viability of the project by demonstrating that acceptable results can be obtained by processing of the ore. The second goal is to obtain essential supporting data to determine whether the project is economically feasible. This involves several functions, which include the establishment of a workable flowsheet, the obtaining of design criteria for the commercial plant, and the collection of the evidence necessary to convince management, and often a third-party expert, that the metallurgy predicted for the ore can be achieved in a full-scale operation. The latter task is facilitated if a coherent overall picture is presented considering the geology of the orebody, the mining plan, and the mineralogy and metallurgy of the ore. The purpose of this paper is to provide guidance in the establishment of a test programme to meet the above objectives.

Jan 1, 1978

By F. H. Deist, R. P. Plewman

The history of development of analytical techniques for the determination of elastic behaviour around tabular excavations, is examined briefly. The design of a completely digital system, which appears to afford considerable improvements in speed, accuracy and versatility compared with existing analogue methods, is described in detail. The practical application of this system is illustrated by means of an actual underground problem. The results are presented, not in the form of specific solutions to the mine's problems, but as indications of the versatility and scope of the new method.

By V. Matou?vek

The paper addresses pipe flows of aqueous medium-sand slurries at velocities lower than the deposition-limit velocity. Laboratory test results including measurements of particle concentration distributions are used in order to describe a flow with a (pseudo-) linear concentration gradient above a stationary bed. Particle dispersion within the flow is evaluated and a stratification-ratio equation is formulated, estimating a portion of contact load in the flow. The formula is incorporated in the proposed predictive model for the hydraulic gradient for a medium-sand flow above a stationary bed.

Jan 1, 2007

By R. du Preez

Tati Nickel is currently operating a hydrometallurgical demonstration plant in Botswana, using the Activox® process developed by LionOre Technology to produce nickel cathode and a cobalt salt from a sulphide concentrate. Cobalt is extracted using Cyanex 272. This reagent also extracts all the iron, aluminium, copper, zinc, and manganese from the nickel stream. Versatic 10 carboxylic acid is then used as extractant to recover nickel from the stream, separating it from calcium and magnesium, and upgrading it to provide a suitable advance electrolyte for nickel electrowinning. However, the selectivity of Versatic 10 for nickel over calcium is limited, and gypsum formation in the extraction circuit is a problem when attempts are made to maximize the recovery of nickel. Mintek has developed a synergistic system with Versatic 10 for improved separation of nickel from calcium and magnesium. Laboratory testwork was conducted on the raffinate of the cobalt solvent extraction circuit to optimize the Versatic 10/Nicksyn? (Mintek synergist) system to be employed. Extraction and stripping parameters suitable for this stream were optimized in the laboratory and then applied on the demonstration plant. A commercial batch (0.5 tons) of Nicksyn? reagent was produced for the demonstration plant. The laboratory testwork results and the demonstration plant performance are discussed in detail in this paper.

Jan 1, 2007

By P. M. Swash

A mineralogical investigation of the main causes of refractoriness of some metalurgicaly complex gold ores in South Africa is reported. It is shown that this refractoriness is related to the presence of submicroscopic gold, carbonaceous material, pyrhotite, and base-metal sulphides. Gold ores can be classified according to their content of these components. Electron-microprobe analysis shows that gold occurs in arsenopyrite and pyrite, the gold contents of which can be up to 2700 gft. The gold and arsenic contents of these minerals are closely corelated. Furthermore, within zoned arsenopyrite grains, the concentration of gold closely folows that of arsenic. Mossbauer spectroscopy caried out on samples of concentrate from the Barberton area indicates that the submicroscopic gold within the sulphides is in a non-metalic form. The mineralogical examination of beneficiation products is important, since it sheds light on some fundamental aspects of the behaviour of the ore and gangue components during milling and flotation. Such basic information will lead ultimately to a better understanding of the problems in the beneficiation of these ores. Investigations have shown that the overmiling of the auriferous arsenopyrite and the disseminated nature of the sulphide mineralization are the main problems during beneficiation.

Jan 1, 1988

By S. Konetschnik, E. Dreyer, A. Filzwieser

"More intense furnace operations require effective cooling in order to achieve low refractory wear and good furnace lifetimes, making cooling technology an important aspect of furnace operations. However, the use of water - today’s standard cooling medium - has some disadvantages, as it can cause problems both during furnace start-up and operation, namely hydration problems, corrosion, and explosions. Apart from these aspects, the energy that is removed by extensive cooling cannot be recovered and is normally lost in the cooling towers.With METTOP’s new patented cooling technology it is possible to overcome the disadvantages of water by using an alternative cooling medium, namely ionic liquids (ILs). The main advantage of ILs is the fact that there is no risk of explosion should this liquid come in contact with molten metal. Furthermore, ILs can be used at higher temperatures than water - up to 200°C. This relatively high cooling medium temperature avoids hydration and corrosion problems and allows recovery of the energy by combining the ILTEC system and the organic Rankine Cycle (ORC) technology, for example.Due to the removal of the explosion risk, much higher safety standards can be achieved, particularly in critical areas such as tap-holes"

Jan 1, 2014

By J. Tikka, E. Bäcklund, N. -O. Lindfors

Tornados are the most violent weather events in the world, and we have all seen the forces and phenomena created by tornados in nature. Airgrinder AB has been working with a material treatment technology, which most easily could be described as an artificial tornado. The process consists principally of one air fan providing a high-velocity airstream that enters a mechanical cyclone. When the gas enters the cyclone, an outer vortex is created. This outer vortex rotates next to the cyclone wall, and at the bottom of the cyclone funnel the gas stream is turned and an inner vortex is created. The control of the air flow is tuned by a special device on top of the cyclone. The gas outlet is at the top of the cyclone and the material outlet at the bottom. The material is fed through a feeding device into the air stream channel prior to the inlet into the cyclone. The process is basically an improved grinding and dehydrating system, which is very efficient and environmentally friendly and can even be employed with very sticky materials. Also due to its rotating comminution, the material particles become rounded during grinding, hence more free flowing and easier to handle. MEFOS has already tested more than 30 different applications in the pilot equipment. The materials tested range from metallurgical slags containing 2?3% moisture to sludges with up to70% moisture. This technology has a potentially strong impact on mineral beneficiation, including the drying of sticky fine-grained materials, improved and selective gas scrubbing and the manufacture of free flowing powders.

Jan 1, 2007

By R. R. Mankowski

The work described here is an extension of current theory applied to obtaining the power dissipated at the wavefront of a transverse disturbance traveling along a mine hoisting cable. A previously derived empirical relation is adapted to the present problem, and is solved by use of a Lagrange-type reference frame moving with the wavefront. As a result of tie limitations inherent in the original relation, only a lower-bound for the domain of predicted power losses is defined. A qualitative assessment of conditions leading to the undesirable effects of internal frictional losses at the wavefronts are discussed in terms of the operating environment found on typical mining installations

Jan 1, 1990

By A. Whillier

Recovery of energy from the water going down mine shafts by A. WHILLIER, Pr. Eng., Se. D. (M.I.T.) (Fellow) The influence of energy-recovery systems on the rise in temperature of water going down mines is examined. It is concluded that the, cost benefit of such systems, deriving partially from the reduced temperature rise in situations where cold water IS sent underground from surface, would more than justify the installation cost.

Jan 4, 1977

By M. R. Khalesi, S. Arfania

"Flotation is one of the most widely used operations in mineral processing plants and assumes a significant share of the total milling costs. The purpose of this paper is to introduce a new set of capital and operating cost models for major flotation machines based on the application of single (SRA) and multiple regression analysis (MRA). Thirty-seven major flotation machines were analysed for this purpose. Depending on the machinery type, different technical variables such as diameter, required air flow rate, required floor space, cell volume, required air pressure, and power were considered as predictor variables, individually (in SRA) or simultaneously (in MRA). Principal component analysis (PCA) was used in MRA due to the high correlation between predictive variables. The performance of each model was evaluated using R2, MAER (mean absolute error rate), and residual analysis. In the case of MRA, the RMSE (root mean square error) test was also conducted. Maximum obtained MAER of 13.5% and minimum R2 of 0.86 indicated that these models could be applied as credible tools in estimation of capital and operating costs of flotation machines for design and feasibility studies.IntroductionMineral processing is a vital part of mining projects and mainly involves comminution, sizing, concentration, extractive metallurgical processes, and dewatering. Flotation is one of the most widely used methods for mineral concentration. Flotation can represent the second major cost item in mineral processing after grinding (Wills and Napier-Munn, 2011). Accordingly, it is a main concern of mining project managers to select and optimize flotation circuits in order to decrease costs and increase productivity. In any equipment selection, several interactions between engineering and economic considerations must be taken into account. Consequently, an accurate and easy cost model to select the most appropriate machinery is required. Moreover, cost models could be used in flow sheet simulations applied in design and optimization. Models of unit operations built into the simulators could be improved by linking the equipment cost models (Khalesi et al., 2015)."

Jan 1, 2017

By T. R. Marrero, J. W. Wilson

The transportation, by water that flows through a pipeline, of coals in the form of water-impermeable cylinders is discussed, and shown to have distinct advantages over other forms of coal transportation, including significantly reduced costs for larger throughputs. The description of the concept comprises various aspects of the system, such as methods for the manufacture of coal logs, their injection into the pipeline, the manner in which they are conveyed in the water in the pipe, and the methods used for their preparation as feed material to electric power stations at the end of the pipeline. It is pointed out that the technology involved in the transportation of coal in the form of logs via pipelines is applicable also to other minerals and commodities.

Jan 1, 1993

By C. Mueller

Automation of mining operations is pushed by cost pressure and cyclical product prices. However, until now the different types of equipment were not able to communicate electronically with each other or with central computer systems. Therefore, the International Rock Excavation Data Exchange Standard (IREDES) was launched by major players in the industry. The task of this initiative is to define a ‘common electronic language’ for easy and standardized data exchange. As in other industries, this standard is expected to have significant impact on the use of automation in general and on the markets for third party components and software. The standard’s technical architecture is open and flexible for future applications. It consists of an ‘horizontal’ structure defining ‘Application Profiles’ for different types of data sets. An additional ‘vertical’ structure (‘Equipment Profiles’) implements equipment dependent definitions for each of the applicable Application Profiles. First profiles will be available for Drill Rigs. The standard bases on the XML language thus enabling easy data exchange with commercial databases. IREDES data sets may use storage media as well as networking infrastructures for information exchange. The IREDES work is carried out by the initiative members working jointly together in the IREDES work groups. It is open for participation of all interested organizations. First prototyping applications are expected to start during 2001, the first products may be available in the following year. Key words: Mine Automation; Machine Automation; Data Exchange; Rock Excavation; Standard; Remote Control; Teleoperation; Ethernet; TCP/IP; Internet Technology; Service; Quality Assurance; Control Centre;

Sep 1, 2001