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By M. Le Roux

Fine coal (-500 µm) is notoriously difficult to dewater. It is not uncommon for a dewatered product to have a moisture content as high as 30 per cent after vacuum filtration. This poses several handling and financial problems to such an extent that a lot of fine coal is discarded onto slurry waste ponds. A novel way of dewatering fine coal was developed at North-West University. It entails deliberately damaging the filter cake during dewatering to allow for an increased flow of air through the cake at the expense of the applied pressure differential. This method resulted in an average improvement in final cake moisture of between 3 per cent and 5 percent when executed in the laboratory under controlled conditions. A device was designed that could be fitted onto existing belt filters that would damage the filter cake as it passes by. This device was tested on a vacuum belt filter installation at a coal beneficiation operation in the Waterberg coal field in South Africa. The results showed a 3 per cent reduction in final moisture of the cake, proving the validity of the method at full industrial scale.

Jan 1, 2012

By P. Altounyan

Techniques used to safely control the roof in UK coal mines for some 10 years have been applied to a South African coal mine. This new approach known in the UK as advanced rockbolting technology, is based on applying four fundamental principles: ?Understanding the roof failure mechanisms ?Using an effective roof support system ?Designing this support using measurement ?Monitoring the performance of the system. The paper summarizes the approach in detail and describes how it is being applied by Anglo Coal, giving results obtained to date. Investigations at a number of South African coal mines, including stress measurements at two Anglo Coal mines, have confirmed that the mode of roof failure (lateral shearing due to horizontal stress) is the same as in other coalfields worldwide, and aspects of current world best practice, including the use of advanced technology rockbolting, are therefore relevant in South Africa. The stress measurements indicated a high level of stress field anisotropy and further investigation of stress conditions in South African coal mines is recommended. The most effective bolting system to resist shear failure is one with high bond strength and stiffness. Short encapsulation pull testing of existing South African systems confirmed that they have low bond strength and stiffness. An improved rockbolt system with the required performance, and features allowing rapid installation and installation quality and performance audit, has been developed and is currently under full-scale trial. Design by measurement and routine monitoring procedures including the use of a rotary telltale device are also under trial. It is anticipated that South African coal mines will be able to obtain significant safety and productivity benefits from the application of this technology.

Jan 1, 2001

By Q. X. Yun

This paper provides a new approach to optimize the production planning in underground mines by means of evolutionary algorithms. Firstly, genetic algorithm is used to reach the global optimization in planning. Then, evolutionary programming is employed to obtain the partial optimization for each year. The application proves that the new approach is reasonable and useful. Keywords: Evolutionary algorithm, Genetic algorithm, Evolutionary programming, Optimization, Mining engineering.

Jan 1, 2003

Surface Plasmon Resonance (SPR) spectroscopy, combined with cyclovoltammetry, has been successfully used to study the interactions between ethyl xanthate, heptyl xanthate, dithio-phosphate and propyl trithiocarbonate flotation collectors and a gold surface. Large, easily measurable responses have been obtained in the potential areas where the thiol collectors are known to interact with gold. The four collector types lead to differing SPR maximum values, with longer alkyl chains resulting in higher SPR responses, and the trithiocarbonate leading to the highest response values. The SPR responses differ considerably from the current density response at very anodic and cathodic potentials. There are indications that thiols might still be adsorbed at potentials as low as-300 mV (vs SHE). Keywords: flotation collectors; thiol collectors; cyclovoltammetry; surface plasmon resonance spectroscopy.

Jan 1, 2005

By L. A. Thompson, A. J. Linington

"Copper–cobalt extraction is a reagent-intensive process resulting in acid consumption greatly contributing towards production costs, which in the current market conditions curtail profitability. Nanofiltration (NF) membranes have become an attractive approach in the mining and minerals industry for product concentration and reagent recovery based on the ability of the membrane to separate monovalent ions from divalent ions. NF membranes can selectively separate acids from metals and salts allowing acid to be recycled as well as the concentration and purification of product streams. Membrane technology in the field of copper–cobalt processing focusses on the concentration of Cu2+ and Co2+ in the pregnant leach solution, recovery of acid from waste streams to neutralization, recovery of valuable metals from waste ponds and process water recovery. This paper aims to provide insight into the potential applications of NF membranes in copper–cobalt processing circuits as well as a brief overview of the effects of process conditions on membrane performance and process development. INTRODUCTION The copper–cobalt industry commonly uses inorganic acids, such as sulfuric acid, in large quantities for primary leaching of copper–cobalt oxide ores and releaching during product purification (Stuurman et al., 2014). This results in numerous acidic intermediate streams containing high metal concentrations and acidic waste streams with low metal concentrations. Acid consumption typically accounts for 10–15% of the operating costs of mines in the Democratic Republic of Congo (DRC) and Zambia (Acid Plant Database, 2015). Due to remote mine locations, poorly maintained roads and cross-border conflict, the cost of sulphuric acid can range between USD 300 and 400 per ton. The pivotal role of acid in the copper–cobalt extraction process has driven many mines to build sulphuric acid plants on site to ensure a reliable acid supply, however elemental sulphur still needs to be imported which faces similar logistical challenges and contributes towards operating costs."

Jan 1, 2015

By M. Le Roux

Fine coal (-500 µm) is notoriously difficult to dewater. It is not uncommon for a dewatered product to have a moisture content as high as 30 per cent after vacuum filtration. This poses several handling and financial problems to such an extent that a lot of fine coal is discarded onto slurry waste ponds. A novel way of dewatering fine coal was developed at North-West University. It entails deliberately damaging the filter cake during dewatering to allow for an increased flow of air through the cake at the expense of the applied pressure differential. This method resulted in an average improvement in final cake moisture of between 3 per cent and 5 percent when executed in the laboratory under controlled conditions. A device was designed that could be fitted onto existing belt filters that would damage the filter cake as it passes by. This device was tested on a vacuum belt filter installation at a coal beneficiation operation in the Waterberg coal field in South Africa. The results showed a 3 per cent reduction in final moisture of the cake, proving the validity of the method at full industrial scale.

Jan 1, 2012

The re-use of waste water from coal preparation plant tailings is always desirable, but is generally problematic in terms of solid-liquid separation. Dewatering and disposal of coal slurry at a high percentage of moisture poses a major technological and environmental challenge to mining and mineral processing industries world-wide. Characterization and flocculation of these coal tailings reveals that the separation of fine coal tailings depends on factors such as size distribution, slurry viscosity, zeta potential, pulp density, circuit design, plant operating parameters, and the behaviour of solid particles in an aqueous medium. The present study was carried out on -600 mm coal tailings collected from a coking coal preparation plant of Jharia Coalfield, India, using anionic flocculent. Characterization studies revealed that the zeta potential was highest (-44 mV) at a pH of 9.0, the size range of the particles was 1.1?700 m, and the average ash content was 62.57%. Flocculation studies were performed at different solid concentrations, pH values, and polymer dosages. The results indicated an efficient settling rate of 178.15 mm/min at 8% solid (w/w) at a flocculent dosage of 32.50 g/t solid. The turbidity of the clear liquid obtained was 7.42 NTU.

Jan 1, 2014

By M. Reuter, U. Boin

The target of the current metallurgical industry is to recycle and utilize all their by-products, so as to close the sustainable production loop. Slags are the important wastes and by-products of metallurgical industry, which have been treated, recycled and used worldwide. The present paper summarizes the current status of utilization of the various slags from ferrous and non-ferrous metal production, as well as waste incineration, and recycling of salt fluxes in secondary metal production. In addition, the environmental issues of the metallurgical slags are addressed. The metallurgical oxide slags have stone-like properties and, thus, their major applications are in civil engineering field. The slags should be recycled, modified and processed in a proper way, by taking the environmental impact into consideration. With the treatment of salt slags for melting aluminium scraps, as an example, the recycling and elution properties of the salt slags are discussed. Our research indicates that the viscosity of the salt flux is increased with addition of non-metallic components, that a certain percentage of fines remain in suspension, which determines the viscosity, affecting the settling of heavier materials. High slag viscosity will lead to more fine aluminium metal entrapped in the salt slag (may also be seen as a high temperature slurry), and thus increase the load of salt slag recycling. Keywords: recycling, environment, metallurgy, slags, fluxes, salts.

Jan 1, 2004

By G. C. Smith

Process control applications in the minerals processing industry have grown extensively over the years due to the many benefits derived, both financially and operation-wise. Although control theory is widely known, conventional control does not address many of the problems posed by minerals processing circuits. Some of these problems include interactions between process units, large dead times, few and sometimes unreliable measurements of process variables, non-linear systems, disturbances entering the process, processes with varying dynamics, and many more. For the past 26 years Mintek has been active in the field of providing specific, customized solutions for the minerals processing industry. This paper focuses specifically on applications in milling and flotation control. The underlying control principles have been applied to a wide range of other processes including submerged arc furnaces. Advanced control application is implemented on a common advanced control platform, called the PlantStar. Much innovation has been brought to the fore in terms of adapting theoretical techniques and developing new methods to resolve specific milling and flotation circuit issues by using process control. The general approach adopted by Mintek when implementing advanced control is to enforce stabilization of the process as a solid foundation for optimization strategies to be built upon. In doing this, a robust control solution is presented, and the end result is flow and level stability, better product quality regulation, increase in throughput and a stable feed to downstream processes. The MillStar advanced milling control system ensures that the milling circuit is at all times easy to operate while achieving optimum product quality and throughput. Stabilization should include product size regulation and sump level control. Another important aspect of stabilization control is the handling of milling circuit constraints without introducing cyclical behaviour and with minimal disturbance to the final product quality. Process constraints may include factors such as process water limitations, cyclone feed density, and cyclone underflow angle. An optimization strategy should be developed to increase the mill throughput without affecting product quality or introducing mill overloads. The relationship between solids feed and power draw is examined and manipulated for optimization. The interactive nature of flotation circuits and the presence of recirculating streams tend to make satisfactory control almost impossible with conventional techniques such as PI (Proportional plus Integral) or PID (Proportional, Integral and Derivative) control. The FloatStar Level Stabilizer simultaneously considers all the flotation levels in a circuit by use of a multivariable algorithm, and takes compensating action in anticipation of disturbances. The FloatStar Flow Optimizer is an optimization strategy that controls the concentrate flow rate between various sections of a flotation circuit (e.g. Rougher ?Cleaner; Cleaner ?Recleaner). By controlling the concentrate flow between the sections, the mass pull, circulating loads and residence times of the circuit can be stabilized, thereby enhancing the performance of the flotation process. Optimizing grade and recovery are coupled with the dynamic optimization of circulating flows. The FloatStar Grade-Recovery Optimizer will maximize the grade in a section, whilst ensuring that recovery or any other process specific limits remain within predefined limits. With successful applications on several milling and flotation plants worldwide processing amongst others PGMs, gold, copper and nickel, Mintek has shown that it is a leader in milling and flotation control innovation

Jan 1, 2004

By J. Kortnik

Mining has always been, and still is, an activity which is vital for the development of mankind. This is because a predominant proportion of industrial products and energy is produced from raw materials that are excavated using mining methods. The need for environmental protection and the close proximity of urban settlements and mines in Slovenia have necessitated ever stricter requirements for the excavation of raw materials and introduction of more environmentally-friendly mining methods. This is achieved by implementing a closed eco-technological cycle of raw material excavation within the scope of mining methods. In surface mines, this means prompt reclamation of the degraded surfaces, and in underground mines the use of methods with minimized impact on the surface and on underground water. In underground mines, mining methods with backfilling installed according to the multi-barrier disposal system are the only ones that allow the possibility of implementing a closed eco-technological cycle of excavating raw materials. Various industrial waste materials are also included in the backfilling material in order to improve its strength properties. Backfilling consisting of several different waste materials is produced in the form of a composite. Before backfilling consisting of waste material composites can even begin to be used in mines, an environmental impact assessment of its suitability for mines needs to be made. In order to make such an assessment, a pressure leaching cell and an open diffusion cell were made, i.e. a pressure leachate test and a sorption test were developed. The two cells and the developed tests will enable the study of the influence of backfilling on the environment if installed in an underground mine. The pressure leachate test performed with the use of the pressure leaching cell simulates leaching from a consolidated backfill during the seeping of underground water into the backfilling material under pressure. The sorption test performed in an open diffusion cell simulates the flow of eluate leached from the backfilling material through the rock/geotechnical barrier. The two tests were developed in such a manner that they are performed either in succession immediately after one another, but they can also be performed separately at a certain time interval. The paper presents an assessment of the suitability of backfilling made of different waste material composites. Keywords: environmental impact assessment, multi-barrier disposal system, waste material composites, pressure leachate test, sorption test, pressure leaching cell, open diffusion cell, eco-technological cycle, mining methods with backfilling.

Jan 1, 2003

By R. J. Hundermark

Keywords: Anglo American, Anglo Platinum Ltd, Waterval, Mortimer, Polokwane, ACP, pyrometallurgy, platinum, PGMs Anglo Platinum Ltd is the largest primary platinum producer in the world and operates three smelters in South Africa: Waterval, Mortimer and Polokwane. The operational details of the smelters are covered in previous reviews, thus only unit operations that have been upgraded are discussed. The most significant of the upgrades include the installation of a second ACP converter at Waterval Smelter in 2006 and the anticipated upgrade of Mortimer Smelter to 38MW in 2011. Several advances have been made in the smelting operations to improve the furnace stability and longevity. Control of the chromium input to each of the smelters has substantially allowed continued operations at levels below the spinel saturation point in slag, which results in lowered matte and slag temperatures. Mogalakwena concentrate, arising from the Platreef ore, is used to dilute high chromium-containing concentrates. In addition, furnace controls have improved in terms of crucible temperature and condition monitoring, improved feeding control, management of alarms and trips and having the quality of instrumentation and operational rigour required to support this. Advances have been made on the ACP converter in terms of good converter matte quality, and increased intensity and efficiency of operation. Combined with improvements to both the conventional and tower sulfuric acid plants, the emissions from Waterval Smelter have been reduced substantially since the introduction of the ACP. This is in spite of increasing metal throughput. The Anglo Platinum Ltd smelting operations have made significant progress since 2006 and further advances are envisaged to further improve on safety, reduce costs, increase efficiencies and throughput, while reducing emissions.

Jan 1, 2011

By B. Samanta

LHD (load haul dumper) is now used as a loading machine for intermediate mechanization in underground coal mining. For survival in the intense competition in the global business environment in recent years it is essential that LHD machine should be reliable and maintained effectively and efficiently. This paper seeks to study the reliability, availability and maintainability (RAM)of an LHD machine with failure and repair data by Markov modelling. The constraints and reasons for machine unavailability are outlined. The reliability and maintainability of an LHD and its subsystems are evaluated. Possible modification or design alternatives are highlighted. Reliability and maintainability of an LHD system are disappointing. There is room to take decisions on optimal maintenance planning and machine improvement from this analysis. Keywords: reliability, availability, maintainability, Markov model, LHD

Jan 1, 2004

By T. Celik, B. Genc, C. Musingwini

"Mine planning software continues to be an important factor when it comes to the development of the South African mining industry. To contribute to this development, a new methodology to define and measure mine planning software utilization in the South African coal mining sector within an evolving data-set framework was developed. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgy in 2013. In 2014 the data-set was updated with additional and new information.In this paper, using the 2012 and 2014 time-stamps, a methodology for estimating the software utilization is developed. In this methodology, three variables: commodity, functionality, and time factor are used to define and measure the software utilization in order to ultimately inform decision making strategies for software utilization. Utilization in the coal sector was measured according to six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation and Optimization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and wanting to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2016

By Noel C. Joughin

In making judgements on tolerable levels of risk in industry, and in all spheres of life, it needs to be understood that every action gives rise to risk. Without risk, nothing can be done. Without risk, no economy could be advanced. There is a strong tendency to emphasize the risk at work, but persons who are not working are exposed to a different set of risks. Often persons who are not working face greater risks than persons who are working. Simply, in being alive, one is exposed to the risk of an accident, the risk of contracting a disease, and an extremely diverse variety of other risks. According to the Health and Safety Executive of the UK, it is not possible to have a state of zero risk, because ?a state of zero risk does not exist?. Because zero risk is a physical impossibility, it is not possible to design for a state of zero risk in all engineering design. While the strategic target of achieving zero risk is laudable it does not provide any practical guidance to engineers as to what acceptable limits of risk should be. This causes a significant and real problem in the design for and the management of risk. Without meaningful guidelines, engineers, managers and the authorities often find themselves in disagreement. Thus, it has become essential to establish criteria for tolerable levels of risk and unacceptable levels of risk in order to design and manage engineering systems properly.

Jan 1, 2011

By G B. Gnoinski

The Skorpion Zinc Mine and Refinery is situated approximately 25 km north of Rosh Pinah, south-western Namibia. The supergene zinc oxide deposit at Skorpion is hosted in a volcano-sedimentary succession within the para-autochthonous Port Nolloth Zone of the Gariep Belt. Rock types hosting the ore deposit include altered and metamorphosed volcaniclastic and clastic sediments, limestone and rhyolite. At Skorpion, the metallurgical process is unique and the plant design requires minimal fluctuations within a selected feed grade. In addition, the presence of limestone inter-fingered with ore in some areas of the deposit results in dilution problems which may increase gangue acid consumption and therefore processing costs. Hence, selective mining is necessary to ensure the delivery of suitable ore to the processing plant, in order to keep the overall operating costs at a minimum. A complex control system is in place and is capable of a high degree of selectivity. The paper describes the grade control system in place at Skorpion Mine which ensures that the qualities of the blocks planned for mining and the material being mined meet the stringent process requirements of the refinery, i.e zinc grade, gangue acid consumption and deleterious elements that may impact on the efficiency and costs of the metallurgical process. Keywords: Skorpion zinc, zinc oxide, supergene, volcano-sedimentary, grade control

Jan 1, 2007

By S. K. Murphy, S. M. Spottiswoode, A. M. Milev, D. Geyser

A portable, stand-alone instrument especially designed for recording strong ground motion was used in this study to create a large database of peak particle velocities measured underground. A total number of 39 sites located in stopes mining Carbon Leader and Ventersdorp Contact Reefs were investigated. Peak particle velocities whith values up to 3 m/s were recorded at some sites. The data recorded on the skin of the excavations were compared to the data recorded by the mine seismic networks to determine the site response. The maximum site response was obtained for source radii of between 5 m and 30 m and events locating within 200 m of the site. The extreme values of peak particle velocities were obtained in cases were the face-area lay within the source radius. Un instrument portable unique spécifiquement conçu pour enregistrer les mouvements dynamiques des terrains, a été utilisé dans cette étude pour créer une base de données importante sur la vélocité maximum des particules, mesurée en souterrain. Un nombre total de 39 sites situés dans les excavations exploitant les récifs appelés ‘Carbon Leader et Ventersdorp Contact Reefs’, a été investigué. Une vélocité maximale avec des valeurs allant jusqu’ à 3 m/s a été enregistrée sur certains sites. Les données enregistrées sur le bord de l’excavation ont été comparées aux données enregistrées par les réseaux séismiques de la mine pour déterminer la réponse du site. La réponse maximum du site a été obtenue pour des sources de rayons entre 5 m et 30 m et des évènements situés dans les 200 m du site. Les valeurs extrêmes de vélocités maximales ont été obtenues pour les cas où la zone de face se trouve à l’intérieur du rayon de la source. Ein mobiles, alleinstehendes Instrument, speziell entworfen um starke Formationsbewegungen aufzuzeichnen, wurde in dieser Studie verwendet um eine große Datenbank von Partikelspitzengeschwindigkeiten, die Untertage gemessen wurden, aufzuzeichnen. Eine Gesamtanzahl von 39 Aufstellungsorten in den Schichtabbauorten vom Carbon Leader und Ventersdorp Contact Reef wurden untersucht. Partikelspitzengeschwindigkeiten mit Werten bis zu 3 m/s wurden an einigen Standorten aufgezeichnet Die an der Oberfläche des Grubenraumes aufgezeichneten Daten wurden mit jenen Daten verglichen, die vom seismischen Netzwerk der Grube notiert wurden, um die örtliche Reaktion des Standortes zu bestimmen. Die maximale Standortreaktion wurde für Ursprungsradien von zwischen 5 m und 30 m erhalten und Ereignissen die sich innerhalb von 200 m vom Standort befanden. Die extremen Werte der Partikelhöchstgeschwindigkeiten wurdenin jenen Fällen erreicht wo sich der Abbaubereich innerhalb des Ursprungsradiuses befand.

Jan 1, 2003

A diverse selection of rockbolt designs and resin anchors are available for use in underground mines. Research in recent years at the UNSW Mining Research Centre led to the construction of a rockbolt pull-testing facility. This facility has subsequently been upgraded, commissioned and initial test work has been completed to verify the pull-test process. A test program has been completed with the objective to understand the load transfer mechanism and improve the general performance of rockbolts. This paper describes the results of this research. Une sélection diverse de dessins du rockbolt et ancres de la résine est disponible pour usage dans les mines de métro. Faites des recherches ces dernières années à l'UNSW que le Centre de la Recherche Minier a mené à la construction d'une facilité de l'essai de la traction du rockbolt. Cette facilité a été améliorée par la suite, le travail de l'épreuve en commission et initial a été complété pour vérifier le processus de la traction-épreuve. Un programme de l'épreuve a été complété avec l'objectif comprendre le mécanisme du transfert de la charge et améliorer la performance générale de rockbolts. Ce papier décrit les résultats de cette recherche. Eine verschiedenartige Auswahl an rockbolt-Designs und Harzankern ist dafür verfügbar, benutzen Sie in unterirdischen Bergwerken. Forschung in letzten Jahren beim UNSW-Bergbau Forschung Zentrum führte Ruckerprobung-Einrichtung zur Konstruktion eines rockbolt. Diese Einrichtung ist anschließend befördert worden, ist beauftragt worden und wird abgezeichnet, prüfen Sie, die Arbeit ist vervollständigt worden, um den Ruckprüfung-Prozeß zu verifizieren. Ein Prüfungsprogramm ist mit dem Objektiv vervollständigt worden, den Lastübertragungsmechanismus zu verstehen und die allgemeine Aufführung von rockbolts zu verbessern. Dieses Papier beschreibt die Ergebnisse dieser Forschung.

Jan 1, 2003

By S. D. Dladla, S. Ramsamy

The majority of the tailings dam operations in South Africa will be required to comply with the new Global Industry Standard on Tailings Management (GISTM) within the next one to three years, depending on the dam classification and the requirements of the respective investors and insurers. With up to 72 auditable requirements, the implementation of the Standard needs careful planning and prioritization. This paper focuses on the practical steps to GISTM compliance for tailings facilities in operation in South Africa. The discussions are based on current practices, South African regulations, and industry standards requirements. The possible changes in dam classifications and the associated requirements are presented.

Jun 2, 2022

By F. Habashi

The first documentary evidence for the use of fire to extract a metal was furnished by the wall paintings of the ancient Egyptians showing workers using the blowpipe and bellows to increase the temperature to melt gold in a crucible. Furnaces grew in size and complexity, coke replaced charcoal in the blast furnace, and the Industrial Revolution took place in England that gradually spread worldwide. More metals became known and new techniques were introduced for their extraction. Among these, metallothermic reactions became prominent in the nineteenth century immediately after the discovery of the electric current and its use to liberate the alkali metals from their salts. Once these metals became available, they were used to produce aluminium from alumina that resisted all other methods of attack. Aluminium, now available on a large scale, was used to decompose the most stable compounds and liberate more metals that became the basis of modern civilization.

Jan 1, 2004

By Ernie Holden, Chris Ringas

In the last 20 years, In Line Inspection (ILI) using intelligent pigs has become the principal tool used by pipeline operators to assess the condition of their pipelines. New pipelines are normally designed to take intelligent pigs, but many older pipelines require some modifications and special procedures for their inspection. This paper is aimed at practicing engineers and managers of pipelines, or people aspiring to those positions. The paper describes the benefits of ILI and some of the practical issues regarding pipeline preparation and cleaning, choice of inspection tool, running pigs in pipelines, and what to do with the data collected. What are the responsibilities of the Pipeline Engineer ? ? Maintain reliable and acceptable performance of the pipeline in terms of safety and product delivery at economical cost. ? Provide a defined margin of safety for operating the pipeline at its designated pressure. ? Provide timely information on all pipeline defects such that repairs can be carried out according to a managed schedule. What Defects does the Pipeline Operator have to cope with ? A useful record of actual incidents seen in pipelines can be obtained from the web site of the US Office of Pipeline Safety (OPS) - http://ops.dot.gov/stats/stats.htm. US pipeline Operators are obliged by Law to report all pipeline incidents exceeding certain threshold criteria (e.g loss of life, escape of product, cost of incident etc). These OPS statistics show that corrosion and third party damage have remained consistently the prime causes of reportable incidents in the US, with similar experience elsewhere. There are several kinds of flaws and defects in pipelines that can lead to failure, the main families being :- ? Metal loss ? Cracks or crack-like defects ? Laminations and other mid-wall defects ? Geometric anomalies

Jan 1, 2006