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By Terry S. Cory

This report covers magnetic field strength measurements vs range and frequency in low-medium coal mines. Both quasi-conductor-free and conductor-proximity areas were investigated. The program covered 5 mines, 4 seams, 6 measurement sets, and 3 geographic areas. The results have been summarized in terms of maximum communication range expected per seam and noise condition. Scatter gain is further explored as a simple measure of energy coupled to conductors.

Jan 6, 1978

By A. H. Mumin, A. Prikhodko

"This paper provides an understanding of interpreting and evaluating airborne time domain electromagnetic (TEM) surveys as applied to massive sulfide exploration. Variations in the conductive morphologies of massive sulfide ore systems are discussed, followed by forward modelling exercises examining the derived TEM response to these morphologies and discussion of the subtleties of data interpretation. Deposit morphology in the orientation at formation and the variations occurring due to later deformation are considered. Images of corresponding resistivity–depth models are provided. The combined modelling results provide a low-cost method for initial interpretation and screening of TEM anomalies. RÉSUMÉ Cet article nous permet de mieux comprendre l’interprétation et l’évaluation des levés élec-tromagnétiques aéroportés en domaine temporel (TDEM, de l’anglais time-domain electromagnetic) appliqués à l’exploration du sulfure massif. Y sont débattues les variations au niveau des morphologies conductrices des systèmes de minéralisation du sulfure massif, suivies d’exercices de modélisation prospective qui examinent la réponse dérivée des TDEM à ces morphologies et d’une discussion sur les subtilités de l’interprétation des données. L’étude envisage la morphologie de l’orientation originelle non déformée des gisements ainsi que les variations résultant d’une déformation ultérieure. Des images des modèles correspondants de résistivité-profondeur sont fournies. Les résultats combinés relatifs à la modélisation proposent une méthode peu onéreuse d’interprétation et de contrôle initiaux des anomalies dans les TDEM.INTRODUCTION Electromagnetic geophysical surveys are an indispensable foundation of many mineral exploration programs and can account for as much as half of the predrilling exploration costs. Quantitative mass interpretation of the survey results remains difficult due to the infinite variation of deposit morphologies, their complex physical properties, and the presence of barren conductive materials that can mimic or mask the response of targeted ore. Many modern geophysical investigations that focus on time domain electromagnetic (TEM) data interpretations are devoted to problems with inversion and modelling and their algorithms. Although a few of these investigations have resulted in commercial software products, these require highly qualified and experienced users and usually include geometric assumptions. Furthermore, without the input of known physical properties and geometric constraints, the inversion results are highly ambiguous. A number of case studies document the geophysical responses to known targets in well-defined and diverse geo-electrical environments, providing a high degree of correlation between field obser-vation and the results of the modelling used in this style of investigation (Hone, 1980; Schneider & Emerson, 1980; Tyne, Idnurm, & Malone, 1981; Bishop & Lewis, 1992; Hopgood & Hungerford, 1994; Meju, 2002; Yang & Oldenburg, 2016). The uniqueness of the target/environment parameters and their specific features limits the use logy is poorly understood. The responses are therefore that are devoid of complicating environmental factors (e.g., highly conductive overburden and hostrocks or nonuniform target conductivity) as a first approach to the interpretation process of such case studies as the main reference for interpreting TEM survey responses in areas where the underlying geomodelled from generalized and typical geological models"

Jan 1, 2018

By F. Cherpereel, R. Gabillard, J. P. Dubus

We present an electromagnetic method taken from the well known radiogoniometer that allows us to locate at the surface of the ground the vertical axis of a magnetic antenna transmitter buried at a depth h in the earth. The method and the equipment achieved are called R. E. P. E. (Relevé Electromagnétique de Points Enterrés). They are daily used to accurately survey old quarries by using triangulation instruments at the surface of the earth rather than in galeries where the setting difficulties considerably reduce their accuracy and increase the work length. The results of several surveys allow us to give the optimum working conditions of the instruments and show that, when the transmitter is at a 20 meters depth, its position is known at the surface with an error lower than 1 centimeter. The power transmitter is of about 8 watts and we can find its location with an error smaller than 1 meter when buried at a depth of about 100 meters. This equipment may be successfully used for location of subsurface miners. The space surrounding the transmitter must then be free from ferromagnetic bodies.

Jan 1, 1973

By Lorant B. Geller

Sixteen miners died tragically at the Paymaster gold mine at Timmins, Ontario in February, 1945, when a badly corroded hoist rope broke. The investigation of the Royal Commission that followed arrived at a number of recommendations (Investigations, 1947) aimed at avoiding future disasters of this kind. One consequence was the development, and legislated use in Canada, several decades ago, of powerful electromagnetic (EM) instruments for the nondestructive testing of mine shaft wire ropes. The authors have been involved for many years in the design, production, and testing of EM instruments (Geller and Udd, 1990 and 1992, Geller and Kitzinger, 1991, Geller et al., 1993). Since the mid-1990s particular attention was paid to the design and operational results obtained from the computer- controlled portable MagnographJ II wire rope tester (Geller et al., 1995 and 1998). In the present article the authors summarize further hardware- and software-related developments of this instrument. Further, an account is given of the results obtained from the most recent design known as the PermaScanJ testing system. This is also a computerized dual-function system. In it, however, the sensor head is designed primarily, if not solely, for permanent installation and for remotely controlled operation. This represents a basic departure from traditional designs, which were intended for ad hoc temporary installations. The remotecontrolled instrument described in this paper has now been in operational use for more than 4 years.

May 1, 2003

By Tim Robinson, Georges Houlachi, Michael Moats, Marco Ginatta, Michael Free, David Creber, Neale Neelameggham, George Holywell

"Electrolytic processing is used commercially to recover and/or refine metals such as aluminum, copper, magnesium, nickel, and zinc. There are also new and exciting opportunities to utilize electrometallurgy in the production of titanium, lead, and other metals. This paper reviews some of the main technologies that are used to produce and refine metals as well as some of the recent advances and future directions the electrometallurgy industry may implement to meet the challenges faced now as well as those that are likely to be faced in the future.IntroductionElectrolytic processing is used commercially to recover and/or refine metals that include large scale production for metals such as aluminum, copper, magnesium, nickel, and zinc as well as small scale production for metals such as gold and silver. There are also new and exciting opportunities to utilize electrometallurgy in the production of titanium, lead, and other metals. This paper will focus only on electrometallurgical processing of metals with relatively large production markets."

Jan 1, 2012

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By M. Jahazi, M. Brochu

This paper describes the advantages/disadvantages of electron beam freeforming using two different types of filler metal: (1) brazing paste and (2) solid wire. Sound buildups were obtained from both filler metal. The freeforms produced with the brazing paste showed a certain level of porosity, which was reduced by successive melting. In comparison, the solid wire buildup was practically free of pore. When compared with the solid wire filler, the brazing paste produced narrower buildups but a larger scattering of the width.

Jan 1, 2004

By Vadim J. Jabotinski

Electron beam processing is potentially very attractive for the high temperature treatment of hazardous materials. The very high power efficiency of the electron beam energy source (80- 90% of the power from the electric power line is converted to useable energy) is one of the positive features of this technique. This paper will consider advanced electron beam concepts for solid, liquid, and gaseous waste treatment such as stabilization of radioactive solid and liquid hazardous streams. Fundamental aspects and applications including an analysis of the economic potential of electron beam processing of waste treatment will be presented.

Jan 1, 2000

By N. Rowlands

The importance of mineralogical and chemical characterization of fine particles in the fields of mineral and metallurgical processing is discussed. Emphasis is placed on electron beam analysis techniques including electron diffraction and energy dispersive analysis with special reference to the scanning trans- mission electron microscope. The correct choice of instrument depending upon particle size, composition and nature of sample is stressed and the analytica1 capabilities of different types of instruments are evaluated. Recent applications of electron beam equipment to processing problems are presented and the paper concludes with a review of new developments in the fields of surface analysis and micro-diffraction.

Jan 1, 1985

By Osamu Takai, Yoshiki Sato, Nobuhiro Tajima, Hiroyuki Sugimura

"Amorphous carbon thin films doped with nitrogen ( a-C:N) have been synthesized by means of shielded arc ion plating (SAIP). Their electron field emission properties, that is, threshold field strengths for electron emission and maximum emission current densities, were evaluated and compared with those of pure amorphous carbon (a-C) films prepared by the same SAIP apparatus. Among all of the fabricated a-C:N films, the a-C:N films with a N concentration of 23 %, which prepared using Nz arc plasm at a pressure of 1 Pa with applying a sample bias voltage of -100 V, showed the lowest threshold filed of 13.4 V/µm and the highest emission current density of 1.87 µAfcm2 at a field of20 V/µm. These field emission properties of the a-C:N film were much better than those of the a-C films. The best results obtained on the a-C film in this study were the lowest threshold filed of 15.5 V/µm and the highest emission current density of 0.052 µA/cm2 at a field of 20 V /µm. Nitrogen doping to aC was found to be effective for lowering threshold voltage for field emission and for increasing emission current density. The electron field emission characteristics of the a-C:N films depended not only on N concentration but also on chemical bonding state of nitrogen in the a-C:N films. The presence of the ~-C3N4-like phase, which contributes to improve wear resistance of a-C:N as well, distinguished by the NlsXPS peak at 400.5 eV is proved to be crucial in order to enhance field emission properties of a-C:N.IntroductionThere has been much interest in electron field emission from a cold cathode due to its potential applications in vacuum microelectronic devices including field emission displays which are expected as flat panel displays in next generation [l]. It is well known that efficient emission can be rather readily realized using tip-like shape cathodes, e.g., microfabricated three-dimensional electrodes [2], carbon nanotubes [3-5], etc. However, electron emission from planar surfaces is of particular importance since such a type of cathode is· simply fabricated and assembled into microelectronic circuits. Currently, amorphous carbon thin films doped with nitrogen (a-C:N) prepared by plasma processes have attracted attention because their threshold voltages of field emission are relatively low [6]. Among various methods for preparing a-C:N films, the process using arc plasma is of special interest since, in arc plasma, nitrogen is highly activated and new types of carbon nitride phase are expected to be synthesized. However, field emission properties of a-C:N prepared by arc plasma have been studied in less detail compared with that prepared by the other methods such as sputtering."

Jan 1, 2000

By C MacRae, N Wilson

CSIRO Minerals has recently developed an electron microprobe (EMP) based imaging (or mapping) method for characterising ilmenite concentrates. The method requires an electron microprobe analyser to collect elemental X-ray maps which are then processed via an in-house developed software module (CHIMAGE). The type of information readily available from EMP mapping includes; primary phase identification, modal analysis of phases, chemical analysis of individual phases, textural information (eg the alteration stages in the formation of leucoxene or pseudorutile from primary ilmenite and the development of macro-porosity), and the identification of coatings or pore-fill material. All of these parameters will impact on the choice of future downstream processing options considered for any particular ilmenite concentrate. The method has been demonstrated to be a sensitive analytical tool for assessing the distribution of aluminosilicate minor impurities in ilmenite feedstocks from the West Coast of Australia and also for characterising the complex chrome-spinel gangue phases common in East Coast ilmenite concentrates from the Murray Basin.

Jan 1, 2001

By O. E. Omotoso

This study is part of an ongoing investigation to understand the mechanism of stabilization/solidification of hazardous chromium wastes in ordinary Portland cement (OPC). Tricalcium silicate (C3S*),a major component of OPC is mixed with reagent grade Cr(lll) and Cr(VI) solutions, to simulate complex cementiCr waste systems. Scanning electron microscopy (SEM) and energy disperse spectrometry (EDS) were employed to provide microstructural and chemical information. Transmission electron microscopy (TEMlEDS), apart from complimenting the SEM, was used to probe the distribution of Cr in the hydration products of C3S and to provide crystallographic information. 29Si MAS NMR (magic angle spinning - nuclear magnetic resonance) Was used to characterize the influence of Cr on the hydrated silicate structure.

Jan 1, 1995

"Mechanical alloying (MA) synthesizing technology and thennohydrogen processing (THP) were utilized to produce nanocrystalline Ti-MMC's reinforced by TiB intermetallic compound by using TiH2-B powder mixtures. Powders MA'ed up to 8 hours were examined by X-ray diffraction and SEM study. All MA'ed powders afterwards were HIP'ed at 700, 800 and 950EC for 1 hour. Detailed XRD, SEM and TEM study of the samples were carried out to determine the structure and micrography of the Ti-TiB MMC material processed by MA+THP approach followed by HIP'ing at high temperatures.IntroductionThe fiber reinforced titanium base composites [1,2] which possess a great resistance to high temperature have been investigated. In these studies fibers of C and SiC were used as reinforcing materials. However, these fibers react with Ti-matrix at elevated temperature resulting in product formation at the interface between the matrix and the fiber. Because of the chemical reactions, strength of the product MMC material diminishes.In conventional techniques of whisker reinforced composite material production, the mixtures of matrix metal powders and dispersed fibers are consolidated by hot pressing, HIP and/or hot extrusion. These techniques, however, have some shortcomings. Hard and brittle fibers could be broken during mixing cycle of the processing. Consolidation techniques could also be the cause for fiber breakdown. Attaining of the uniform dispersion of fibers into the metal matrix is not an easy process. The chemical reactions at elevated temperature exposures in the interface between the matrix material and fiber reinforcement cause product formations leading to poor mechanical properties."

Jan 1, 1998

By N. S. Dalal, B. Jafari, X. Shi, M. M. Suryan

"It is well known that prevalence and severity of coal worker's pneumoconiosis (CWP) differ markedly in different regions and mines despite comparable exposures. These variations in the pathogenicity of different coal mine dusts can only partially be explained by the mineral composition of the coal mine dust and the rank of coal. Laboratory studies also do not correlate with the human experience. One major difference between human exposure and laboratory studies is that the coal miner breathes dust from freshly broken coal, while the animals or cells are exposed to stale dust. In an effort to find biochemical clues for resolving this apparent paradox, we have carried experiments to detect differences in chemical reactivities of fresh versus stale coal dust from several U.S. coal mines. Electron spin resonance (ESR) was used as a technique for the direct detection of the concentration and reactivity of free radicals. ESR measurements of freshly ground coal dusts of different ranks and composition showed significant differences in the amount and reactivities of the organic free radicals produced. The half-lives and reactivity patterns of these newly formed species of free radicals seem to correlate with the expected toxicity and pathogenicity of the dust, thereby, providing new clues to the biochemical mechanisms and pathogenesis of CWP. Similar detection of free radicals in freshly crushed quartz suggest that free radicals might play a significant role in the pathogenicity of quartz in causing fibrosis and eventually silicosis.IntroductionThe pathogenesis of coal workers' pneumoconiosis (CWP) has been an important topic of concern for decades, but the mechanism of CWP is still not understood. It is well known, for example, that the prevalence and severity of CWP differ markedly in different regions and mines despite com¬parable exposure'(1,2) but these observations can only par¬tially be explained by differences in mineral composition and rank of coal (3-5) Specifically, while epidemiological studies of coal miners indicate (1,2) that the effectiveness of coal in producing CWP correlates roughly with the rank (i.e. %,carbon content) of coal, such correlation has not been established via biological studies.(4-6)"

Mar 1, 1989

By H. L. Ludtke

Microlaminate composites were fabricated by electron-beam physical vapor deposition. The microlaminates consisted of five layers, each 2 to 4 pm thick, and were composed of either pure metal layers (Cu-Ag), or alternated between metal and intermetallic layers (Nb(Al)- Nb3Al). The microlaminates were heat treated in an Ar atmosphere for 2 to 12 hours, at temperatures of 600°C for the Cu-Ag and 1000°C to 1200°C for the Nb(Al)-NbsAl. Microlaminates were examined after deposition and after heat treatment by scanning electron microscopy and energy dispersive x-ray spectrometry. The effects of heat treatment on the morphological stability of these composites will be described.

Jan 1, 1999

By J. G. Debanne

MOST company-employed petroleum engineers have in their accounting departments punch-card computers that can perform engineering calculations thirty to three hundred times faster than desk calculators, or they can rent such machines from Computing Service centres. These machines not only eliminate the drudgery of desk calculation but also the risks of human errors. The I.B.M. t 604 punch-card computer of Texaco's accounting department in Calgary has been used for oil and gas property evaluations, curve fitting by least squares, statistical core analysis studies, unsteady-state water in-flux studies, phase equilibrium performance prediction of oil reservoirs, gravity segregation calculations, etc.

Jan 1, 1958

By Steve Brace

Electronic detonators have been commercially available to the mining industry worldwide for over ten years. It is estimated that total cumulative global sales will have reached 25 million units by the time of the Conference in February 2004. This is below 0.2% of all detonator types sold during this period. Perhaps 20 million will have been used underground in South African gold, diamond and platinum mines. These will have been produced by South African companies, in South Africa for South African customers. Here efforts have met with greater success and in 2003 fully 5 million, or 3% of local detonators sold, could be of an electronic type. However, it is estimated that about US$7.00 (R50.00) has been expended on R & D, manufacturing facilities and marketing, for each unit so far sold. Large sums of money continue to be spent. Despite the apparent success in South Africa, is it justified? Electronic initiation systems have not produced significant technical benefits to the end-user underground nor corporate profits to the supplier. Some doubt they ever will (even from the large surface operations where the price per unit is much higher). A conclusion might be that they have failed. In 1998 Smit and Pistorius wrote a paper titled “Implications of the Dominant Design in Electronic Initiation Systems in the South African Mining Industry”. This ISEE paper seeks to summarise and review the conclusions of the earlier work. These were: that a dominant design had not yet emerged; the type of connector and the way in which detonators are connected and programmed would be a strong determinant influencing the development of a “winning” product; technical aspects rarely solely determine which becomes the dominant design (marketing, social and economic factors often have a strong influence); electronic initiation systems were an emerging technology for the underground gold mining industry in South Africa and because it was under severe cost pressure the mines would look to them to raise productivity and hence profits; finally, as a dominant design begins to emerge, one could expect a number of players to exit from the industry.

Jan 1, 2004

By Laurent Airaud

For around ten years, electronic detonators are available for those who want to use advanced methods and to apply theories promoted by engineers and professors to reduce blast concerns or improve fragmentation and dilution. Furthermore, decision makers can verify the use of electronic detonators to drive down mining costs. Engineers and more specifically blasters are the actual users and have to be convinced of the easiness of electronic detonators. This paper deals with electronic detonators and the notion of easiness. Common feelings about the notion of easiness are discussed. Then, examples of new technologies like, automobile, photography or Information Technology are discussed to observe how they progressed throughout time with new features and sales volume. For the specific explosive initiation industry, each step of the life of an electronic detonator is dealt with concerning the easiness and a table is used to quantify this notion.

Jan 1, 2004

By Tristan Worsey, Nathan Rouse, Evan Thibaud

Electronic detonators allow for variability and accuracy with blast delay selection and timing sequence. However, a single published guideline for selection of electronic timing delays is not available on the OneMine database. There are published documents that present options for timing with electronic detonators, some of which provide great detail and scientific evidence, but there is no single document that presents several different approaches with simple instructions on how to apply the various timing approaches. This paper reviews published electronic timing approaches and results, then presents guidelines for electronic timing for alternative mining methods, which include: bench blasting (ie. quarries) and crater blasting (ie. metals mines). Most of the approaches are based on calculating milliseconds per meter for rock types, as quantified by the rock sonic velocity. Guideline calculations are provided for recommended hole-to-hole delays and row-to-row delays for both free-faced bench blasting and crater blasting approaches. These are the two most common blasting methods for mining operations. Typically, free-faced bench blasting is the approach used in quarries with a bench height to burden ratio of around 4, and crater blasting is typically used in large blasthole diameter/short bench blasting in metals mines with a bench height to burden ratio of around 1. Mines may focus on fragmentation, mucking rates, ore movement distance and movement direction. Recommendations are also included to provide general recommendations based on a mine’s preference for movement and fragmentation. References include twelve studies on bench blasting and six studies on crater blasting. In addition, a discussion is included on the application of these recommendations at a full-scale surface gold mine.

Jan 21, 2025

By Douglas Bartley, Kevin Hachmeister, Rich Barry

The use of explosive energy as a tool in mining and construction is the most effective way to move large amounts of rock that is otherwise unable to be efficiently excavated. Since the early days of explosive engineering utilizing black powder initiated by cap and fuse to the present day diversity of specialty products and technologies the goal has always been to "Break and Move" as much rock for the least expense possible. It has primarily been the competitive nature of our economy that has driven the advancement of technological innovations and practice. However, the concept of removing rock is not specific to the mining and construction industry. Since the dawn of creation, man has used rock as a medium to express his creativity in the form of sculpture. Even though the process of sculpture requires the removal of rock, the final work is defined by the rock that remains intact. This typically necessitates the extreme care of the sculptor to painstakingly chip away the rock allowing the image to emerge from the original mass of stone. The famous sculptor Michelangelo once said, "I saw an angel in the marble and carved until I set him free."

Jan 1, 2004