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By F. F. Skiba, P. J. Root

A mathematical model has been used to investigate crossflow effects in a stratified reservoir during an idealized displacement process. A process in which one incompressible fluid displaces completely another incompressible fluid of the same density and viscosity was considered. The reservoir was assumed to be composed of homogeneous layers which are discrete but interconnected. Approximate five-spot flow geometry was simulated by arranging two pie-shaped cylindrical (two-dimensional) wedges in series. Some of the common production methods rely, for their effectiveness, on the fact that the formation consists of isolated strata. This is particularly true of selective plugging and single-zone production-injection methods. The effectiveness of these techniques for several cases in which adjacent strata are in communication has been evaluated. The usual production-injection schemes for fluid injection processes involve using the same completion interval in both the production and the injection wells. The efficiency of this, as well as alternative productioz-injection procedures has been examined for some cases involving communicating strata. INTRODUCTION The performance of many fluid injection projects is marred by early breakthrough and by production of a high percentage of the displacing phase after breakthrough. This channeling effect, if it occurs in reservoirs which have large permeability variations, is often explained on the basis of a model composed of discrete, isolated strata. Corrective or preventive measures based on this same model are also common. The behavior of stratified models has been the subject of considerable study. An excellent review of the early literature was given by Seba.1 Studies of the depletion performance have since been made for continuous, unrestricted communication between strata2-4 and for production from one permeable bed in continuous but restricted communication with an adjacent permeable bed.5,6 Model studies of displacement processes in stratified systems with crossflow also have been reprted.7-12 Finally, methods which account for crossflow have been developed for computing displacement behavior in stratified systems.13,14 Most methods for controlling or preventing channeling involve some change in the interval open to production and/or injection. Although many variations of the selective completion problem have been studied in regard to the depletion of a reservoir, little attention has been given to the behavior of a displacement process under similar conditions. Sebal used a resistance network model to study the performance of a process in which one incompressible fluid displaces an identical fluid from a linear, stratified reservoir. He investigated the possibility of improving the vertical coverage by limiting the completion interval of the production well. This investigation deals with techniques in which selective completion of the production and/or the injection wells is used in an attempt to control channeling. At one extreme, selective plugging and single-zone isolation (assuming perfect execution) should be successful if the reservoir is actually made up of independent strata. At the other extreme, they can hardly be expected to be successful if the channeling is caused by a mechanism in which stratification effects are negligible even though there are extreme variations in the formation permeability and/or the injectivity profile of the wells is not uniform. By contrast, it is difficult to anticipate the effect that the amount of communication between the beds of a stratified system will have on the efficiency of selective completion techniques. The objective of this study is the quantitative determination of the effect of communication on the behavior of some particular stratified systems which will at least lead to qualitative conclusions.

Jan 1, 1966

By N. M. Safaya

Moderate to acute deficiency of plant available phosphorus is very common in western coal mine spoils and topsoils. Although some of the spoils are known to contain seemingly adequate amounts of total phosphorus, the plant available phosphorus is so low that it constitutes a serious plant growth limiting factor in the mined lands. For the revegetation of these spoils, the use of species, varieties and ecotypes exhibiting greater efficiency for P uptake and utilization, or conversely, lesser susceptibility to P deficiency would be highly desirable. To identify such plants, quick and adequate methods of screening germplasm should he available. In the present growth chamber study several plant species were screened using continuous flow culture and spoil culture systems to provide information on their relative susceptibility. In flow cultures, P was maintained at 0.25, 2.5, and 25 moles; while in spoil cultures it was applied at 0, 25, and 75µg/g to a P-deficient spoil. Phosphorus deficiency symptoms appeared in alfalfa cultivars, birdsfoot trefoil, emerald crownvetch and yellow sweetclover within 7-10 days upon transfer of their seedlings to U.25 or 2.5 µM P solutions. Burning bush and Russian thistle, found abundantly as pioneering species on mine spoils, showed no deficiency symptoms; their shoot dry matter yield in the 0.25µM P treatment was 24% and 36%, respectively of their maximum yield obtained with 25 µM P. However, the percent increase in the dry matter yield of legumes with 0.25 µM P ranged from 7-13% over their maximum yield. With the increase in solution P concentration, the root dry weight ratio in the legumes increased from an average of 0.22 to 0.43, while in the weeds from 0.14 to 0.30. The low susceptibility of Russian thistle to P deficiency was also demonstrated in the spoil culture experiment. Legumes showed greater response to P-fertilization on the spoil than did the two weeds. With increasing concentrations of P in the solution, the root weight ratio of all the species decreased. At 25 µM P, weeds invested only 14% of their total dry matter yield in the root fraction, where as legumes and grasses invested as much as 24% and 33% respectively. Weedy species averaged higher P concentrations than the legumes and grasses. The mean P concentrations of alfalfa cultivars were the lowest among legumes. In general, P concentrations increased with the increase in P supply. In the flow culture system, P supply increased the Ca levels of legumes. The mean Mn concentrations were highest in the weedy species. The increases in P supply decreased Zn levels in all of the species. File effects of P fertilization on the tissue concentrations of Mn and Zn in spoil culture were similar to that of flow culture system. From this preliminary study, it may be concluded that the continuous flow culture system is efficient in rapid screening of a large number of species under controlled conditions for their efficiency in adapting to mineral stresses.

Jan 1, 1982

By John C. Machisak

INJURY experience and employment data at all metal mines in the United States and Alaska are presented in this Information Circular for the calendar year 1958. This publication covers the metal mining industries, and contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. These operations report injury and employment information annually to the Bureau of Mines on a voluntary basis. The Bureau is authorized to make requests for such data, and the information submitted contributes immeasurably to the promotion of safety in the metal mining industry. Every effort has been made to make the annual canvass as complete as possible. This publication contains, along with production and development workers, the office employees at the mine location. The metal mines identified in this publication are classified according to the mineral ores mined; that is, copper, iron, lead-zinc, gold-silver lode, gold placer, and miscellaneous metals.

Jan 1, 1962

By A. Golshani, M. Oda, K. Suzuki, T. Takemura

Anisotropic behaviours of OhshimaOshima granite were investigated by carrying out uniaxial compression tests, together with observations of microcracks under an optical microscope. The elastic modulus tensor of Oshima granite at 10 per cent strength,E10, were calculated using theoretically formulation of elastic modulus tensor in terms of the second-rank crack tensor for pre-existing open microcracks. Furthermore, with the assumption of orthorhombic elasticity, the nine moduli of Oshima granite E10were determined by uniaxial compression test. Twenty-onemoduli of samples, calculated without assuming any symmetry, also showed orthorhombic features. Direction of the symmetry axes agreed well with the orientation of preexisting cracks. Comparison of crack tensor-based formulation results with the experimentally determined one show that the anisotropy of elasticity of Oshima granite is caused by pre-existing open microcracks, not by pre-existing healed microcracks and also crack tensor formulation can be used, as a first-order approximation at least, to describe the anisotropy of Oshima granite induced by pre-existing open microcracks. ZUSAMMENFASSUNG: Das anisotrope Verhalten des Oshima-Granits wurde mit Hilfe voneinachsigen Kompressionstests und durch die Betrachtung von Mikrorissen unter einem optischenLichtmikroskop untersucht. Das Elastizitätsmodul von Oshima-Granit bei 10 Prozent Kraft E10wurde berechnet, indem man die Formulierung des Elastizitätsmodultensors, ausgedrückt alsRisstensor zweiter Ordnung theoretisch auf bereits existierende Mikrorisse angewandt hat.Außerdem wurden die neun Module des Oshima-Granits unter der Annahme orthorhombischerElastizität E10mit einem einachsigen Kompressionstest bestimmt. Einundzwanzig Stichproben,die ohne die Annahme irgendeiner Symmetrie genommen wurden, zeigten ebenfallsorthorhombische Merkmale. Die Richtung der Symmetrieachsen stimmte mit der Orientierungbereits vorhandener Risse überein. Der Vergleich der Ergebnisse der auf dem Risstensorbasierenden Formulierung mit der experimentell bestimmten Formulierung zeigt, dass dieAnisotropie der Elastizität von Oshima-Granit von bereits vorhandenen offenen Mikrorissenverursacht wird, und nicht von vorhandenen vernarbten Mikrorissen, und dass dieRisstensorformulierung auch zumindest für eine Annäherung erster Ordnung benutzt werdenkann, um die durch vorhandene offene Mikrorisse induzierte Anisotropie des Oshima-Granits zubeschreiben. RESUME: Les comportements anisotropes du granit d’Oshima ont été étudiés en réalisant destests de compression simple, et en observant les microfissures au microscope optique. Le tenseurdu module d’élasticité du granit d’Oshima sous une résistance de 10 pourcents, E10, a été calculéen se servant de la formule théorique du tenseur de module d’élasticité basé sur le tenseur defissures de second ordre des microfissures ouvertes préexistantes. En outre, sur base del’hypothèse de l’élasticité orthorhombique, les neuf modules du granit d’Oshima ont étédéterminés par des tests de compression simple. Vingt et un modules d’échantillons, calculés endehors de toute hypothèse de symétrie, ont aussi montré des caractéristiques orthorhombiques. Ladirection des axes de symétrie correspondait bien à l’orientation des fissures préexistantes. Lacomparaison des résultats de la formule basée sur le tenseur de fissures avec les résultatsdéterminés expérimentalement montrent que l’anisotropie de l’élasticité du granit d’Oshimaprovient des microfissures ouvertes préexistantes, et non de microfissures préexistantes referméeset que la formule du tenseur de fissures peut servir, au moins comme première approximation, àdécrire l’anisotropie du granit d’Oshima marqué par des microfissures ouvertes préexistantes.

Jan 1, 2003

By Jacob Mathis, Mark Bradford, Alston Noronha, R. M. True

In June 2022, Louisville MSD completed a 6.5-km (4.0-mi), 6.1-m (20-ft.) diameter CSO conveyance and storage tunnel system located along the Ohio River in downtown Louisville, Kentucky. For large diameter shaft and tunnel construction, drill-and-blast operations among other methodologies were used in close proximity to federal, commercial, and residential properties with no impact to stakeholder infrastructure. s one of the rst maor tunneling proects in Louisvilles metropolitan area, this paper explores Black & Veatchs rigorous geotechnical instrumentation monitoring program that provided uality assurance for local stakeholders and afrmed innovative tunneling solutions can be successfully executed in an urban setting.

Jun 23, 2024

By Ross R

Although mining is an old industry its management is quite a new science, and its complications are now being recognised as demanding expert knowledge in many branches of technical and professional education. Not the least amongst these isaccountancy, for probably its most important problem is "How to control the expenditure." Unlike most businesses a mining company stands almost entirely in the light of a purchaser in the world's markets, and not as a seller, except say for product so the established and perfected systems of modern industries cannot be adopted for mining purposes. For this reason it has been left for late years to consider the matter seriously, and now a number of well-managed concerns have devised costs systems to suit their own requirements.Very little, however, has been published and even that is disjoined and difficult to make use of. Some of the costs systems in vogue, although elaborate and imposing, are not of very great value for keeping check on wasteful expenditure, or for displaying the commercial effect brought about 'by any particular change in practice, or by an addition or alteration to a portion of existing plant.

Jan 1, 1912

Water quality standards for some of the substances likely to be discharged to natural waters by the mining industry are discussed. After briefly examining how uses of water can be affected by discharges, standards for suspended solids and turbidity, pH, and toxic materials are considered. Heavy metals are examined in some detail because of recent public concern regarding their discharge. Caution is given in connection with their analysis at the very low concentrations required for management of natural waters. Finally, the issues of what constitutes a water right concentration compliance breach, and the appropriateness of biological monitoring as a condition on a water right are raised.

Jan 1, 1986

Comminution is a vital part of minerals extraction, and therefore of the South African economy. The high cost and throughput-limiting nature of comminution forms a strong motivation for research directed at improving the efficiency of the process. Building on a ten year background of fundamental charge motion research, a new formal UCT flotation and communication group has been formed. The group is also moving strongly into the field of milling circuit modelling and simulation, based on close links formed with the Julius Kruttschnitt Mineral Research Centre (JKMRC) of Australia, and an international collaborative research programme.

Jan 1, 1998

By J. M. Houston

"In October 1982, Rio Algom Limited, purchased a tin prospect near East Kemptville, Nova Scotia, from Shell Canada Resources. This purchase led to the development of the first substantial tin mine in North America. This paper deals with the drillingand blasting operations at Rio Algom, in particular the use of emulsion explosives technology.This presentation describes what emulsion explosives and Heavy AN/FO are, and the support system used to deliver these products to the blast site.HistoryThe East Kemptville mine site was discovered by Shell Canada Resources (SCR) in July 1978. SCR started diamond drilling on the tin prospect in March 1979. After 8220 m of BQ drilling, it was estimated a reserve of 56 000 000 tonnes of 0.165% Sn was present.The property, which is located 54 km northeast of Yarmouth, Nova Scotia (Fig. 1), showed, after a feasibility study that, given an ore treatment rate of 9000 tonnes per day, a mine life of 17 years could be expected.GeologyThe tin deposit of the East Kemptville Mine, occurs in granitic rocks at their contact with metasedimentary rocks. The mineralization is in the form of cassiterite with associated sulphides of copper and zinc. The tin occurs in a stockwork of tin bearing Greisen alteration zones.East Kemptville MineThe mine planned an open pit operation with the first five years being mined at a rate of 14 000 tonnes per day, of which 5000 tonnes will be waste and low grade ore. Eventually, the total mining rate will be 21 000 tonnes per day, including 12 000 tonnes of waste and low grade ore. Figure 2 shows the general layout of the mine site.East Kemptville Chooses Emulsion ExplosivesIn December 1984, East Kemptville Mine awarded the Explosives Division of C-I-L Inc. a contract to supply explosives to the borehole. The system chosen gives East Kemptville the on-the-bench choice of regular AN/Fa, or a high density, Heavy AN /Fa product called SuperAN· or a water resistant emulsion explosive called MAGNAFRAC· for holes that cannot be dewatered.Emulsion ExplosivesAn emulsion is an intimate mixture of two liquids that do not dissolve in each other. Emulsions have contributed to our daily lives in such products as insecticides, salad dressings and cosmetics."

Jan 1, 1987

By B. W. Gandrud

This is the third report published by the Bureau of Mines concerning the washability of Black Creek coal. Both of the former reports.5/6/ dealt with the Black Creek coal at the Bradford mine, Dixiana, Ala., near the northeastern extremity of the Warrior field, whereas the present report is based on float-and-sink tests of coal from what is presumably the Black Creek bed near the southern extremity of the field. Although the Yolande Coal & Coke Co., owners of the property at Yolande No. 6 slope, consider this opening to be on the Black Creek bed, the authors do not feel that there is as yet positive proof that this correlation is correct. There has been little or no development of the Black Creek bed in the Yolande Basin in the past, and a positive identification of the bed at Yolande No. 6 will have to await further exploration and development. The Yolande No. 6 is an exploration slope 3/4 mile north of Rockcastle, Ala. The slope is approximately 400 feet from top to bottom on a dip of 180. As far as the authors can ascertain, coal has never been produced commercially from the Black Creek bed in the southwestern part of the Warrior field. Exploration work in the past has indicated that the Black Creek coal in this area is extremely friable and high in sulfur. Extreme friability would naturally discourage its use as a domestic and railroad fuel, and high sulfur content would be a disasvantage in its use for coking coal. The present study of this coal has been made with particular reference to sulfur elimination on the assumption that it would make a good coking coal provided enough of the sulfur could be eliminated by washing.

Jan 1, 1939

Additional Attractive Force Between Alumina Particles Due to Low Solubility of Dicarboxylic Acids

Sep 13, 2010

The Bureau of Mines conducted large-scale laboratory copper ore leaching tests to enable improving copper recovery from large dump-leaching operations. This was done by comparing leaching progress when copper was recovered from recycled leach liquor either by cementation or by solvent extraction. Copper was leached from 7-ton ore samples at room temperature using pH 2 ferric sulfate solutions. With are samples containing 11 percent minus 0.5-inch fines, no marked advantage in using either of the copper recovery methods was evident after 416 days of leaching. With ore containing 32 percent minus 0.5-inch fines, solvent extraction of copper was advantageous in that 60 percent of the copper was extracted after 568 days, whereas only 48 percent of the copper was extracted when cementation was used. Less acid was consumed during leaching when solvent extraction, rather than cementation, was used for copper recovery. Iron, contributed by cementation with scrap iron, plugged the ore bed containing 32 percent fines.

Jan 1, 1981

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 H M. Ahmed, W S. Dunbar

Construction of cave mining systems requires significant capital expenditure and long-term commitment of human, equipment and material resources before production commences. Risks and uncertainties of these large-scale mining projects are significantly higher than for small-scale projects. This is due to the complexity and interactions of the construction schedule components and the large scale and uniqueness of such projects. One way to successfully manage construction uncertainties that would lead to schedule delays is to include a reasonable cost contingency in the budget estimation. A real options approach based on the least-squares Monte Carlo (LSM) method is used to estimate cost contingency associated with schedule uncertainty in mass mining projects. Cost contingency is estimated as the cost of potential project crashing (acceleration) decisions, which pays for not extending the schedule. While such a significant undertaking is expected to be subject to some delays, these can have an enormous impact on the economic value of such projects. The value of the crashing option was explicitly formalised into the process of valuation, as it is assumed to be a single option being considered in the valuation at every decision point prior to the construction completion date. As a part of the proposed method, a stochastic function for the percentage of remaining scope of work for the remaining duration of the entire project was integrated into a framework of numerical simulations. This ensured that this function can implicitly account for sources of schedule uncertainties for projects represented by multiple and overlapping work packages. The LSM method was applied to a real case scenario in an operating block cave mine, with modified scale and features. The results yielded by the LSM method indicated that significant changes in capital budget allocation stem from variation in a contractor’s risk perception and confidence level of estimated delays.CITATION:Ahmed, H M and Dunbar, W S, 2016. Budget estimation and contingency allocation of block cave construction using least-squares Monte Carlo real options, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 801–808 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By G McMillan, P Mulvey

"Geochemical characterisation is done based upon the geology and metallurgical batch testing prior to commencement of the operation of the plant.  Tailings repository design is based upon geochemical assessment of the waste material, as well as the geomechanical issues associated with storing the waste. The resultant conceptual and detailed design is incorporated into the environmental impact statement (EIS), upon which mine approval is based. The entire environmental monitoring and harm mitigation program, which is usually a condition of the Mine Lease approval, is based upon the applicability of the original characterisation.Tacit to this process is that there is no change in the geochemistry of the tailings, i.e. no change in the implications for acid & metalliferous or saline/neutral mine drainage (AMD/SNMD) generation. But any changes in milling and processing can have a substantive impact on the geochemical behaviour of the tailings metallurgy, and potentially render an operation non-compliant within the conditions of the mine license.Environmental and statutory approval implications for continuous improvements of metallurgy need to be understood because unintended consequences could cost more than the benefits of the improvement, and in some cases cost more than all the profit made from the mine.  Examples uncovered during audit and consultant practice will be presented together with a process to ensure implications for adverse environmental harm and license conditions are fully considered.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Continuous improvement - how changes in metallurgy can have a substantive impact on environmental impact and closure - lessons learnt from environmental auditing, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By Rudolf E. Greuer

This report contains the practical application of a computer program for the simulation of ventilation systems under the influence of mine fires and other emergencies on five hardrock mines. The introduction describes the need for such a program, its basic features, and the range of its applicability which is mainly a function of the available ventilation data. The second chapter discusses program modifications, whose necessity or desirability was, during the application, discovered. The following five chapters, which comprise the major portion of the report, give the detailed description of the program application on the five mines. For every one of the selected mines, the ventilation system, the source of the used ventilation data and their preparation for computer simulations are outlined. Based on data for the airflow distribution solely, fumes concentrations in the mines are calculated for several assumed fire locations. Based on data for airflow and pressure distributions, ventilation disturbances caused by fires as well as the resulting fumes concentrations and temperatures are determined. The consequences for escape routes and the possible means to keep them free of fumes are discussed. To investigate the capabilities of the program, other contaminant sources and other potentially dangerous ventilation factors, like fan failures and changed surface temperatures, are simulated also. The results of the calculations have been entered into ventilation plans which makes them easier to scrutinize. All significant computer printouts have been attached.

Jan 1, 1981

By A. Iannacchione

Longwall mining began within the Pittsburgh coalbed of Pennsylvania (PA) in the early 1970?s. Originally, longwall mine layouts were designed to fit within existing room-and-pillar operations, where panels were limited to that of typical production panels, e.g. a few hundred feet wide by a few thousand feet long. In these early designs, the gate entries were comprised of chain pillars similar to those found along main entry systems or within pillar recovery sections. The modern longwall mine has little in common with their 1970?s predecessors. Today the entire mine layout is designed around the longwall mining method. The longwall panels have grown to well over one thousand feet in width with lengths now measured in miles. In addition, development pillar sizes and shapes are matched to specific performance requirements.

Feb 27, 2013

Mr. Murray said: Having recently returned from a visit to America, it may be of interest to members to hear something from me of the mining fields and metallurgical works which I had the opportunity of seeing, and the impressions which I formed concerning general practice and conditions there, as compared with our Australian standards in the mining industry, and in matters generally.The most striking feature of the North American continent is thehuge plan upon which Nature has built, the multiplicity of immense mountains, rivers, and lakes, the snow-covered tops of the former forming reservoirs for the latter during the summer months, being most impressive to the Australian visitor. Starting from Vancouver I travelled east for over 500 miles through the wonderful Canadian...

Jan 1, 1927

By S. G. Shabestari, S. Saeidinia, P. Mokarian

"The experiments were conducted to investigate the influence of various process parameters in rotary degassing of aluminum alloy AS5U3G. Degassing was carried out by use of argon inert gas. The flow rate of the gas was investigated in the range of 12 to 21 L/min., 350 to 500 rpm rotor speed, 6 to 12 minutes degassing time, and 755°C to 780°C melt temperature. Degassing efficiency was evaluated through measuring the density of RPT samples. By optimizing the process parameters, RPT sample density was increased up to 2.73 g/cm3, which guaranties the production of high-quality aluminum castings. Tensile strength and elongation were increased considerably by degassing process. Scanning electron microscopy (SEM) shows small size and well-distributed microporosity. IntroductionOne of the major problems associated with the casting of aluminum alloys is the formation of gas porosity. Aluminum and its alloys are very susceptible to hydrogen absorption. Because solubility is much lower in solid state than liquid state, hydrogen atoms leave their position during solidification and combine together to form hydrogen molecules. These micrometer- scale cavities, called microporosity, cause the reduction of mechanical properties, particularly strength, ductility, fracture toughness, fatigue resistance, pressure tightness, and corrosion resistance (Laslaz, 1991; Jorstad and Rasmussen, 1993; Sigworth and Wang, 1994; Korasani, 1996; Anson and Gruzleski, 1999; Zhang et al., 2000). To avoid these problems and produce good quality castings, it is necessary to remove hydrogen from the melt. Several methods are available for degassing aluminum melt. One of them is a rotary degassing system using inert gas, e.g. Ar or N2. Various thermodynamic and kinetic factors govern the removal of hydrogen from molten aluminum (Anderson, 1987; Sigworth, 1987; Pignault, 1993; King and Reynolds, 1995). These are some parameters that affect degassing efficiency. Some of them are discussed here and some are examined in this project."

Jan 1, 2004

By H. Powell

"This paper discusses how elemental analysis of conveyed bulk flows in real time using PGNAA (Prompt Gamma Neutron Activation Analysis) technology has resulted in significant improvements in advancing plant control in mineral processing operations. PGNAA through belt, full stream, continuous, multi-elemental, real time analysis technology is explained. Capabilities and limitations in plant operating environments are discussed including comparison with other real time, on-line technologies through review of published information available for on-conveyor minerals applications. Case studies include an iron ore and copper-gold company, both of which consider the technology an essential component in advanced plant control necessary in new process flow sheet designs, rather than an optimisation tool.INTRODUCTION Process operators rely on supply of a reasonable ore quality and consistency from the mine. Unfortunately neither the mining nor process operators have much control over the ore quality once it has been put into the crusher. Grade control typically stops once the material is designated as ore and the process plant operator needs to process it irrespective of quality. Plant control is most effective when technologies measure process streams directly and preferably in real time. Measuring sampling streams that are not representative of the primary flow will result in incorrect plant control decisions. Sampling coarse conveyed flows is expensive and impractical at many operations, however, this does not mean those flows cannot be measured. Investigations to find techniques suitable for real time elemental analysis have focussed on the application of known laboratory techniques to process streams. For conveyed applications, development of neutron irradiation techniques were most promising and early studies indicated potential success for bauxite measurement (Beurton et al, 1995). Tran & Evans (2001) concluded there was no equivalent technology to PGNAA in terms of material penetration power and that the technology was eminently suitable for basic industries such as cement. Nelson and Riddle (2003) evaluated PGNAA for possible use in the phosphate industry by using a unit installed in a cement plant to test performance on phosphate samples and ultimately recommended its use for further characterisation of the mine’s various ore types to improve stockpile allocation and grade control"

Jan 1, 2014