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By Noel Dent

The Electrodet@ Electronic Detonation System Wilere are we going with regard to Accurate, Reliable, Easy to Use and Cost Effective Initiation using electronic initiation techniques? Improvements and applications in theJierd

Jan 1, 1995

Brunswick Mine, one of the largest underground zinc mines in the world, is scheduled to close in 2010 after almost half a century of production. All mines eventually close; some suddenly as a result of unsustainable economic or technical conditions and others, as in our case, as a result of the depletion of the orebody. When the mine is the most significant employer and an economic driver in the region, it is key that the closure is handled in a planned, communicated, well-executed fashion. The following paper documents strategies, plans and activities that are currently taking place in order to ensure a seamless closure that satisfies all stakeholders including employees, management, regulatory bodies and the public. It is an important deliverable for the company that the good will, credibility and reputation that has been built up over the years is sustained throughout the closure process and beyond. A life of mine labour agreement with the unionised workforce, staff retention and recruiting programs, regulatory closure plans, communications and transition adjustment activities will be discussed. The use of a stage-gate style project management tool analysing the risks and key deliverables will be highlighted. It is hoped that the concepts and approaches discussed here may be of value to other operations that will be faced with closure, and its inherent challenges, in the not too distant future.

Jan 1, 2006

By M. J. Beus, M. K. Larson, J. K. Whyatt

U.S. Bureau of Mines researchers reviewed an in situ stress estimate developed from measurements of overcore strain taken at test sites on the 7300 and 7500 levels of the Star Mine near Mullan, ID. Although the field measurements of overcoring strain were found to be useful, significant deficiencies were found in the stress estimation procedure. A new stress estimate was developed incorporating statistical methods and an improved understanding of stress concentration factors for interpreting overcore strains recorded by doorstopper cells. Spatial variability of overcore strains and the implications for stress field variability were explored.

Jan 1, 1995

By Dennis Alan Clark

An increase in construction and quarry operations has necessitated blasting activities in areas once considered rural and in the close proximity of transmission pipelines. A method to determine the maximum allowable bending stress by the formulas outlined by the Battelle Memorial Institute report of October, 1962, and the assumed stress comparison with actual measured data is presented. A direct relationship between pipe stress and ground particle velocity is shown, and a method to predict stress by relating stress to charge weight and distance from the shot point is discussed.

Jan 1, 1976

By Sarah K. DeBono, Alan J. Monaghan, Emmanuel V. Manlapig, Gregory J. Harbort

"The Jameson Cell is a type of flotation machine in which air and pulp are brought together in a vertical tube called a downcomer. Within the downcomer the air and pulp are dispersed into a dense foam of fine bubbles, which creates a favourable environment for bubble-particle collision and subsequent collection of hydrophobic particles. The intense collection zone within the downcomer can be considered similar to the zone between the rotor and stator in mechanical flotation cells.Research into the bubble-particle collision and fluid dynamics of mechanical cells rotor-stator zone has been limited by the difficulty of achieving accurate measurements in production sized machines. With the Jameson Cell the downcomer is largely external and separated from the flotation tank, allowing ready access to the primary contacting zone for measurement and analysis.An investigation has been undertaken into the operating characteristics of the downcomer relating to bubble-particle collision. An effective mapping of the downcomer has been made through measurements of void fraction and bubble size taken across cross sections of the downcomer. Analysis of these measurements has provided an interpretation of the variations in the air and fluid dynamics, bubble size and distribution throughout the downcomer chamber."

Jan 1, 2003

By W. Blake, J. K. Whyatt, T. J. Williams

Researchers at the U.S. Bureau of Mines collected and analyzed over core measurements and other indicators of in situ stress characteristics at the Lucky Friday Mine, Mullan, ID. An analysis of these data revealed that significant local variations in in situ stress are present in this mine and that these variations existed prior to mining. High stresses were found to be associated with the most competent strata and a locked section of a fault. An estimate of the predominant stress field was developed for mine-wide modeling. The estimate shows that the greatest principal stress was oriented north of northwest. This information should provide a basis for mine-wide structural modeling of the Lucky Friday Mine and should generate important insights into localized stress conditions, which may significantly affect both local and mine-to-mine variations in seismicity induced by excavation.

Jan 1, 1995

By Pierre L. Labelle

Non electric Dual Delay initiators have revolutionized many aspects of underground mining. The units are used in all types of underground blasting operations. Some operations, due to the complexity and variety of their blasts, have extremely large inventories of conventional non electric products. The Dual Delay system has drastically reduced these inventories and has added an important element of versatility to blast designs.

Jan 1, 1994

The purpose of this paper is to outline current research on the Paparoa and, at the request of conference organisers, to present a general introduction to the geology of the Greymouth Coalfield as background to more specialised papers. Few results of my present work will be given; these can be presented at the next conference. Briefly, the research aims for an understanding of the controls which depositional environment has exerted on coal character, to be reached by a study of coal type and thickness, shape and extent of seams, integrated with a basinal analysis of the coal measures. An accurate description of the coalfield in these terms should facilitate prediction of subsurface trends, with possible application to the planning of drilling programs, and to mine development. Although study of Paparoa coal types is included here as only part of the research, coal type should be recognised as an important concept which has until revently been almost entirely neglected in New Zealand.

Jan 1, 1979

By F. T. Cawood

The new South African Mineral Policy has major implications on the way mineral rent will be collected and shared between the stakeholders in future. Although the policy does not supply details on how this will be done, drastic departures from practices under the previous dispensation require a new approach. For example, there introduction of the ?right to mine? principle implies that the repealed lease consideration concept will be expanded to all minerals. The new policy also makes provision for predetermined standard terms and conditions for all prospecting and mining permissions. It also states that, regardless of whether the mineral rights are state or privately-owned, all prospecting fees and mineral royalties will be determined by state officials after consultation with the registered holder of the mineral rights. This paper proposes a standard mineral royalty formula that complies with the principles mentioned in the White Paper and has been shown to be internationally competitive.

Jan 1, 2001

By J Ramezani, K Faure, N Mortimer

Western New Zealand can be regarded as a rifted continuation of eastern Australia. Detailed studies of units previously considered to have trans-Tasman correlations are being undertaken within the FRST Programme Mineral Wealth of NZ and its EEZ to test specific connections, and thus add to the exploration framework of NZ. Correlation of two major episodes of granitic magmatism are currently being investigated. These represent the oldest (mid Paleozoic) and youngest (Early Cretaceous) magmatic events that conjoined Australia and New Zealand are believed to have in common.

Jan 1, 2007

By P. K. Naik, B. Das

Flotation studies were carried out to recover carbon values from blast furnace flue dust containing ~30.34% carbon, 4.6% volatile matter (VM), and 65.03% ash. The variables chosen for the experiments were dispersant (sodium hexametaphosphate), pH, collector (diesel oil), and frother (MIBC). The experiments were designed according to a 24 full factorial design method and regression equations for the recovery of carbon and product grade were determined from the data. Experiments were performed to optimize recovery and grade using the steepest ascent method. The maximum recovery of carbon was 90.0% with a concentration of 56.5%, whereas the maximum obtainable grade of carbon was 66.35% with 50.45% recovery.

Jan 1, 2005

By S. Schwartz, T. Bilney

"Over recent years a number of techniques have been developed as part of the AMIRA1 P9 project to represent mathematically or measure directly sub-processes occurring in flotation cells. These include the determination of:•,?a machine parameter (bubble surface area flux, Sb);•,?a froth parameter (froth recovery, Rf );•,?entrainment and drainage parameters (???and d); and•,?an ore floatability parameter (Pi).These flotation parameters allow the plant engineer to develop a model of the flotation circuit that can be used as a powerful tool to diagnose the performance of that circuit. The recently developed JKSimFloat V6 flotation simulator uses these parameters to predict the flotation circuit performance that would arise from changes in operating conditions and circuit configuration.This new flotation technology was applied to the Placer Kanowna Belle Gold Mine in Western Australia. A series of plant surveys, cell characterisation measurements and laboratory batch tests were conducted to determine the flotation circuit model parameters to be used within the JKSimFloat V6 simulatorA thorough flotation circuit analysis was then performed at Kanowna Belle using JKSimFloat V6. The recommendations that were provided by this circuit analysis have resulted in large improvements in the flotation performance at Kanowna Belle. These include a 1.3% increase in flotation gold recovery and a substantial decrease in operating costs. The analysis is still ongoing, however, the benefits already obtained from applying this technology have resulted in a US$1.3 million a year improvement to the mine."

Jan 1, 2005

By A. B. Fox, R. P. Thackray, K. C. Mills

The role of mould fluxes in continuous casting is reviewed. The main functions of the flux are described and the importance of the flux in providing lubrication and the right level of heat transfer between the shell and the mould is described. The major problems of longitudinal, transverse and star cracking, gas and slag entrapment and deep oscillation marks in the steel product and ?sticker breakouts? are analysed. The important physical properties of the flux in combating these various problems are identified. Physical property data for the fluxes are given.

Jan 1, 2004

By T. Watanabe, M. Nakagawa, K. Kimapong

Ultrasonic wave was irradiated on metal surface in water to introduce compressive residual stress. The ultrasonic wave that was oscillated with 19.5 kHz ultrasonic transducer and amplified with a step type horn was irradiated. Slight plastic deformation occurred at the surface region of pure metal such as Cu and compressive residual stress was introduced. It seemed that the plastically deformed depth from the metal surface corresponded approximately to the depth of introduced residual stress. The higher compressive residual stress could be introduced into the surface of Cu-Zn brass and SUS304 stainless steel because work-hardening was simultaneously induced to those alloys. Furthermore, since martensitic transformation was induced by the plastic deformation in the case of SUS304, the compressive residual stress could be introduced more deeply into the surface region. The residual stress of SUS304 reached to the maximum value of 574 MPa by irradiating for 5min.

Jan 1, 2004

The prime objective of geometallurgy is to improve the profitability of mines through the use of spatial models of rock properties that have a significant impact on value. Although a key property is the grade of the component of interest, because it directly influences the revenue from saleable material, increasingly attention is being focused on other attributes. These 'non-grade' variables may have a less direct, but equally profound impact on value, either by reducing potential revenue (eg lowering recovery, deleterious elements, etc) or increasing mining or treatment costs (eg comminution, grindability, throughput, reagent use, etc). Collectively, these variables have been described as 'geometallurgical'. There are three main areas of activity required to realise the value of geometallurgy: 1. acquisition of appropriate data through sampling and measurement, 2. building spatial models of geometallurgical variables, and 3. using these models to optimise value. Each of these is built on the foundation of the preceding step. In building reliable spatial models, it is critical that the amount of error introduced to data by the sampling and measurement processes is understood and quantified, in order that the inherent variability of the component of interest can also be properly understood. Management of the quality of grade variables is now applied (with different levels of diligence and success) across nearly all sectors of the mining industry, not least because of the necessity to adhere to Codes of practice (eg JORC, 2004). The necessity for quality management and at least the broad framework of what to do in practice is reasonably understood by many relevant professionals. There are also a number of tools, including software products, statistical analyses and presentation formats, available for those managing grade data. It is also abundantly clear, that in many cases people have little understanding of why they are doing particular quality control activities, or how to sensibly interpret the results. The same is not true for many geometallurgical variables. In almost all instances the authors have seen, the magnitude of sampling and analytical/measurement error variance embedded in geometallurgical test data is untested and unknown. This is partly because until relatively recently, metallurgical data has mainly been collected for the purpose of process and mill design, with few, expensive tests carried out on 'average' samples of the orebody. Increasingly however, there is a move towards collection of much larger data sets from spatially distributed sampling, and thus a growing necessity to understand the errors inherent in both sampling and analysis of these types of variables, and how to manage them. In order to understand how the quality management practices applied to grade variables can be extended to geometallurgical variables, it is essential to understand the theoretical foundation that supports these practices. This requires an analysis of the concepts that underpin the 'principles of additivity' (Matheron, 1963), the 'theory of sampling' (Gy, 1982, Pitard, 1993), and 'statistical process control' (Shewhart, 1930). Relevant concepts are then integrated to form a foundation to develop methods to improve the quality management of geometallurgical variables. Application of this framework will significantly increase the integrity of geometallurgical data, the reliability of geometallurgical models and ultimately the value derived from implementing geometallurgy. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Mar 1, 2010

By H. Stuart Auvil

Twelve samples of run-of-oven coke were taken at coke plants in the United States and Canada. Sampling procedure was directed toward obtaining the highest possible degree of uniformity in the gross samples, so that variations in results caused by sampling variations were at a practical minimum. Under these conditions the standard deviation of the screen analysis test on 500-pound samples is found to range from 1.2 percent for the 1-inch screen to 4.5 percent for the 5-inch screen. At present, the A.S.T.H. standard method of test requires that results be reported to the nearest 0.1 percent. This implies a higher than actual degree of precision, and revision of the report required by the method is suggested. Much larger Samples than are generally tested are required to reduce normal testing errors to a point where they are not appreciable fractions of the total variations found in a smoothly operating plant. For example, it is deduced that over 100,000 pounds of coke must be screened to determine if ordinary day-to-day variations in screen analysis have appreciable effects on the performance of a blast furnace.

Jan 1, 1950

By M. K. Larson, J. K. Whyatt, F. M. Jenkins

The U.S. Bureau of Mines conducted an overcore stress measurement on the 5300 level of the Lucky Friday Mine, Mullan, ID, to investigate the stress regime around an experimental stope in a rock-burst-prone mine. The result indicated a stress field with unexpected magnitude and orientation [F . 135 MPa (19,600 psi) oriented S 80E1W]. An unusual amount of rock-burst activity was encountered during subsequent excavation. A careful review of the overcore data suggested the overcore strain measurements were valid. Moreover, concentrated rock-burst activity suggested that the measured stress field did exist, but was localized and therefore did not represent the far-field in situ stress field.

Jan 1, 1995

In surface mining operations, ultra-heavy trucks operate on haul road networks which are typically from 10?40 km in length. These road networks are often not optimally designed and maintained and as a result, identifying and remediating road functional defects is problematic. Most surface mine operators agree good roads are desirable, but find it difficult to translate this into an effective road maintenance system. This paper presents a haul road maintenance management system which utilizes an assessment of rolling resistance based on a functional performance evaluation of a haul road, together with mine haul truck operating cost models to derive the optimal frequency of road maintenance. A typical application is presented which illustrates the potential of the technique to manage maintenance as and where needed with resultant reduction in total road user costs and an improvement in service provided for the road user. Keywords: Haul road, surface mining, road maintenance, transportation, pavement design

Jan 1, 2003

By J. du Plooy

Mintek has implemented a training scheme that provides students with the experiential training requirement for the National Diplomas in Chemical Engineering and Extraction Metallurgy. This note describes the main features of the scheme and the course content, and our view of future developments in this area.

Jan 1, 1998

By Kunihiko Takeda, Kimio Imaizumi, Tsuyoshi Arai

"The study on the preparation of mono-dispersed liquid droplet was performed using ultrasonic as one of the steps of producing the perfectly mono-dispersed particle. The ultrasonic system was a 33.6kHz ultrasonic generator, an amplifier, an electric distortion element, and a bolted Langevin type horn installed in .a cell. For the first time, a liquid pillar under a nozzle of the cell ·was stably formed. Then, dense and coarse parts were alternatively constructed by oscillating the wavelength of the ultrasonic.· The diameter of those liquid droplets were found to be· perfectly uniform, therefore, it was measured by ""multiplex photography"" using a synchronized stroboscope with the ultrasonic.- From the results, more than 30,000 of perfectly uniform liquid droplets in 1 second were observed by this method.IntroductionRecently, research on the control of physical form is done in various fields of industry. Some examples are the processing technology of the minute compound material of micro-machines and integrated circuits, and the form control of molecule size like catalysts. There is a need for such material to take on various forms in correspondence to its use. ""Form control"" as used in this study will indicate ""research on physical chemistry factors which determine the size of the material"" and will refer to the contour uniformity of comparatively little particles. A well-known method of preparing particles is to spout a mist of liquid and slurry from a nozzle l) 2). Particles for metals, catalysts and food have been prepared by this method. In this case, although an approximate particle diameter can be decided by controlling the nozzle diameter and the violent outflow velocity, it is not easy to completely control ·the contour and to prepare a particle with uniform diameter. ·However, the preparation of perfectly uniform particles is necessary for solders for the adhesion of electronic wiring 3), ion exchange resins4), catalysts and so on. Large quantities of fine particles and super-fine particles are generated when manufactured in the usual way. Large quantities of these fine· particles and super-fine particles have polluted the internal and external' environments of factories. The products yield' ·decreases, also. From such a background, this study examines the preparation of perfectly uniform particles that could be· collected -100% as products. Recently, NASA has succeeded in the preparation of perfectly uniform particles in zero gravity 5). But the preparation of 'perfectly uniform particles by this method is difficult, and it can not be used in general industry"

Jan 1, 2000