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By Peter Swanson

A seismic monitoring network has been installed in western Colorado (USA) in the vicinity of three underground coal mines to (i) distinguish and characterize seismic activity as either mining related or naturally occurring, (ii) implement a real-time event monitoring and notification tool, and (iii) collect data for use in research studies aimed at quantifying impacts from mining-related and natural seismicity. These potential impacts include dynamic rock mass failures such as coal bumps as well as strong shaking in the vicinity of critical structures such as impoundment dams, reservoirs, mine seals, mine openings, and steep slopes. Examples of two damaging seismic events are presented and the mining and geologic factors attending these dynamic failures are described.

Jan 1, 2008

By John R. Parker

Work places of an underground coal mine are required (30 CFR 1719) to be illuminated while self-propelled equipment is used. Permissible machine mounted systems have been developed and applied satisfactorily to many mining operations. However, some low seam and thin seam equipment has been difficult to illuminate because reliable, direct current systems and compact, low output, low glare luminaires were not available. This program resulted in the design and prototype construction of compact, low glare luminaires and AC and DC power systems, particularly suited to resolving illumination problems on low and thin seam mining equipment. Design objectives were based on enhancing the prospects for thin seam illumination solutions through definition of a product which could challenge markets enjoyed by higher glare luminaires and through reduction of technical risks associated with any new product development as well as the MSHA certification process.

Jan 1, 1982

By Zdzislaw Miczkowski

At KGHM Polska Miedz S.A, a direct flash smelting process is used for smelting of chalcocite concentrate for the production of blister copper. The paper presents a model of complex oxidation process of single concentrate grains smelted at KGHM. The description covers main chemical reactions, phenomena of heat and mass exchange inside the grains and between a grain and the surrounding space. In the model, two zones describing the course of process inside the grain were distinguished: ? The first one, which moves faster towards the centre of a grain, both organic and carbonate carbon are freed, The process takes place without the presence of oxygen and results in an increase of the temperature in the core of the particle. ?The second zone moves slower into the grain and the rate of the movement is determined by the presence of oxygen, In that zone the sulphur is eliminated and the oxidation of the organic compounds vapours moving from deeper layers of a grain takes place. Based on the results of laboratory tests, the coefficients that describe the oxygen transportation into the grain and decide the progress in the chemical reaction were determined, The paper contains the results of model calculations for single grains reacting in environment of various content of oxygen as well as the results of model calculations for the laboratory reactor system.

Jan 1, 2003

By Stephen Gerard Sawyer

This report presents a Fortran IV computer program for the structural analysis of space-frame protective canopies used in underground mines to protect equipment operators from falls of roof, face, or rib. This program entitled CANOPY permits rapid calculation of the elastic strength of a canopy for a variety of static loading conditions. Stresses in, and displacements of each structural member are computed and printed out. Additionally, identification of all members that have commenced yielding, weight of the canopy, total loads on the canopy, and maximum loads that the canopy can sustain elastically are output. Program description, input instructions, program listing, and two example problems are included.

Jan 1, 1972

By Serge Ouellet

Résumé Six modèles métriques de remblai cimenté en pâte (RCP) ont été suivis durant 120 jours par l?utilisation de deux méthodes géophysiques non-destructives : la résistivité et la micro-sismique. Les RCP étaient constitués de trois résidus miniers et de deux proportions de ciment (3% et 6% en poids). En parallèle, des cylindres de RCP étaient utilisés pour évaluer périodiquement l?UCS. La résistivité augmentait quasi-linéairement de 28 à 120 jours pour tous les RCP investigués. Des variations de résistivité selon le type de résidu et le pourcentage de ciment ont été observées. Une équation empirique a été dégagée entre l?UCS, la résistivité, le temps, la densité relative et le rapport eau/ciment (E/C). La mesure de la vitesse des ondes de cisaillement a permis de dégager une équation mathématique de type exponentielle qui relie la résistance mécanique sans correction préalable par les paramètres de la recette de RCP. La réalisation de ce projet avait pour but de dégager la meilleure approche non-destructive afin d?estimer la résistance mécanique des remblais en chantier minier. Sur la base des résultats obtenus, les deux méthodes utilisées ont donné des résultats probants afin d?estimer la résistance mécanique et les deux méthodes sont donc à même d?être utilisées en chantier souterrain. Abstract Six scale models of cemented paste backfill (CPB) were followed during a 120 days period using two nondestructive geophysical methods: resistivity and micro-seismic. CPB were made up of three mine tailings and two cement proportion (3% and 6% by weight). In parallel, CPB cylinders were used to periodically evaluate uniaxial compressive strength (UCS). Resistivity was increasing nearly in straight line from day 28 to day 120 for all CPB models. According to the tailing type and cement percentage, resistivity variations were observed. An empirical equation emerged from UCS, resistivity, time, specific gravity of tailings and, water/cement ratio. The use of shearwave velocity allowed to identify a mathematical exponential equation related to mechanical strength without prior correction of the CPB?s formula parameters. The purpose of this project was to identify the best non-destructive approach in order to evaluate the mechanical strength of backfill in a mine site. On the basis of those results, both methods gave conclusive results in order to estimate mechanical strength and both methods can be used in underground operations.

Feb 1, 2008

By Julie Shang, Tim Evans, Michael McDonald, Yu Guo, Bingfeng Xue

Effective chemical grouting represents a technical and economic solution to many challenges related to soil stabilization and blocking the flow of water. Chemical grouts are facing increasing demands in durability, environmental impact and value. To better meet these challenges, a novel and cost effective process was developed to produce a sodium silicate that increases the ratio (i.e. silica to alkali) beyond what has been used in traditional silicate-based grouts. The move to a lower sodium form of silicate was anticipated to have two desirable performance enhancements; a reduction in leachable sodium and improvement in the durability of the silicate grout. An in-depth study was performed at the University of Western Ontario Geotechnical Research Centre to quantify improvement in durability as well as other performance properties such as compressive strength. The study began by first modelling the gelation time and reaction kinetics of the high ratio sodium silicate over a range of silicate concentrations using two different setting agents as well as with/without a hardener. As expected, reducing the level of sodium produced a much more water resistant grout. These same formulations also showed a four order magnitude reduction in permeability. Somewhat surprising, test results showed the higher ratio silicate having much higher compressive strength. At the time of this abstract, the high ratio silicate was moving to the trial stage for geotechnical applications while the petroleum industry was further along with several successful field trials for water blocking as well as cement remediation. This paper will review the chemistry, testing and features of this next generation form of sodium silicate. Introduction Sodium silicate based grouts have been used for decades for soil stabilization and water control. Over the years, several silicate-based systems have been tailored for specific application conditions to maximize performance and reduce cost. Past research has also focused on the selection of setting agents and hardeners for silicate grouts. A constant in the development effort has been the grade of sodium silicate. The vast majority of chemical grouts have been formulated using a ~3.2 ratio sodium silicate. As a very brief overview on the meaning of “ratio” and why it is so important to performance properties. The ratio describes the proportion of sand to alkali or SiO2:Na2O used to make different grades of sodium silicate. Comparing a 2.2 ratio to a 3.2 ratio, it is easier to polymerize and set the 3.2 ratio. Upon setting and forming a silica gel, the system has higher compressive strength values and improved durability with a reduced level of syneresis (i.e. shrinkage). This leads to the question if 3.2 is better than 2.2 why not go to 4.2 or higher?

Jan 1, 2018

By Anibal Gastañaga

La determinación del cuarzo es un problema dentro de la Higiene Industrial, puesto que este mineral se convierte en una de las enfermedades ocupacionales causadas por la inhalación de pequeñas partículas de cuarzo encontradas en el aire. En ese sentido, el presente texto señala la importancia y peligrosidad de los polvos del mineral a través de la determinación cuantitativa de cuarzo en los polvos industriales, ya que el riesgo de adquirir silicosis es proporcional a la concentración de cuarzo en los polvos ambientales. Existen tres métodos para la determinación cuantitativa de cuarzo: El método químico, el de difracción de rayos X y el petrográfico. El método que presenta mejores beneficios es el de N. A. Talvitie, puesto que se basa en la propiedad del ácido fosfórico, donde se forma complejos solubles en agua con los silicatos y óxidos metálicos, quedando el cuarzo prácticamente inalterado.

Aug 1, 1955

By M Bird, B Oats, M Sganzerla

Mining operations are continually aiming to reduce operating costs to improve plant profitability. One way in which the Cannington operation sought to achieve this was by increasing the wear life and reducing the energy consumption of their flotation mechanisms. This was made possible using Outotec’s FloatForce mechanism. The FloatForce mechanism has been developed by Outotec over a six year period involving both CFD modelling and rigorous site testing. FloatForce delivers improved air dispersion and cell agitation efficiency; as such it can be operated at lower rotor tip speeds when compared to Outotec’s previous mechanism.Cannington trialled three FloatForce mechanisms in a train of ten OK38 zinc roughers. The mechanisms’ rotational speed was reduced by 10% compared to the previously installed MultiMix mechanisms. The purpose of the trial was to quantify the energy saving and assess whether there was any reduction in plant metallurgical performance.The trial was successful with FloatForce delivering a 17% reduction in power, an improvement in wear and improved recovery. Analysis of pre and post-installation metallurgical accounting data showed the following:The FloatForce installation resulted in a recovery increase of zinc to zinc final concentrate of 0.4 – 4.0%*The FloatForce installation resulted in a recovery increase of lead to zinc final concentrate of 0.0 – 0.3%*There was no statistically significant change in silver recovery to zinc final concentrate that can be attributed to FloatForce**95% confidence interval (CI) using multiple linear regression models.The Cannington operation is now in the process of further optimizing its power consumption and wear savings by changing the remaining OK38 zinc and lead rougher float cells to FloatForce mechanisms.CITATION:Bird, M, Oats, B and Sganzerla, M, 2015. Improvements in flotation cell maintenance, power consumption and operation at South32 Cannington, in Proceedings MetPlant 2015, pp 230–245 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

JAMES A. BARR Consulting Engineer Mt. Pleasant; Tennessee Washington, D.C. BEHRE DOLBEAR G COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4. N. Y. BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia LENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 210 La Arcada Bldg. Santa Barbara, Calif.

Jan 1, 1952

JAMES A. BARR Consulting Engineer Mt. Pleasant. Tennessee Washington. D.C. BEHRE DOLBEAR G COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 210 La Arcada Bldg. Santa Barbara, Callf.

Jan 1, 1952

A review is made of the limited published experience of the effects of cemented fill in flotation.A general approach is adopted in listing and discussing possible sources of, and reasons for, ore contamination by cemented fill, together with basic, fundamental approaches to minimizing this contamination. These approaches involve basic mining design, effect of fill placement density, optimization of curing time and of cement content, variation of fill particle grading, use of flocculants and of pozzolans, fill placement and dewatering, and or blasting and handling practice.

Jan 1, 1974

By B. Arlyuk

The complex system has been developed for long-term assessment of world prices and sale volume of primary aluminium when using the analytical model of the market and market supply forecasts as well as economy development in the Western countries characterized by the industrial production indices as correct data of Western World aluminium consumption are absent, The important part of this system is the model developed for forecasting the degree of capacities utilization of smelters and refineries depending on the price level, The model contains a statistic part corresponding to the capacities distribution by the production cost, and a dynamic part determining the deviation from the static depending on the price variation dynamics, The developed complex system has been identified by the actual data of the world prices of smelter grade alumina and primary aluminium, conservation and reactivation of refineries and smelters in the Western countries within the period from 1992 to 2003. The system was used for primary aluminium and alumina price forecasts till 2020.

Jan 1, 2004

By I. Ward, E. Milosavljevic, M. Botz

"The silver nitrate titration method is a rapid and acceptably accurate means of analyzing for cyanide in leach solutions that contain primarily free cyanide. However, in leach solutions containing elevated levels of copper, the titrimetric method overestimates the concentration of free cyanide and underestimates the concentration of weak and dissociable (WAD) cyanide. The authors have developed a modified potentiometric (MP) titration method for determining WAD cyanide that overcomes issues associated with high copper levels in solution. The new MP-WAD method involves addition of a chemical ligand to the sample prior to silver nitrate titration to release cyanide bound to copper. Once released from copper, cyanide in solution is no longer affected by the presence of copper, and titration results are quantitative rather than empirical. In multiple laboratory trials with synthetic solutions and complex actual leach solutions, analytical results obtained with the new MP-WAD method were found to be within about ±5% of analyses obtained with the USEPA OIA-1677 WAD cyanide analytical method.IntroductionThe silver nitrate titration method is widely used to estimate the concentration of cyanide in leach solution for purposes of cyanidation process control. Cyanide determined by silver nitrate titration is commonly referred to as “free” cyanide, but frequently should be referred to as “titratable” cyanide. By definition, free cyanide is the sum of the concentrations of aqueous hydrogen cyanide HCN(aq) and the cyanide anion CN- (ASTM, 2010). Titration will only yield a reasonably accurate measurement of free cyanide when metal-cyanide complex concentrations (e.g., cadmium, copper, mercury, nickel, silver and zinc) in solution are low. In other words, titration will only yield a reasonably accurate measurement of free cyanide if the solution primarily contains free cyanide."

Jan 1, 2015

By D. Harrington

This circular presents part I of a review of the literature on effects of breathing dusts, with special reference to silicosis, largely in the minim; and allied industries. The literature on this subject is so extensive that no attempt has been made to include all published material but only to assemble some of the more outstanding data on several aspects of the subject. Parts II and III will deal with prevention and treatment of dust diseases and some of the economic and legal aspects of dust diseases in industry, with special reference to mining. Dust diseases arc much before the public at present, and there is good reason to believe that the information on the subject available to the layman is extremely meager; even those rated as experts usually have a more or less theoretical conception of the diseases, their causation, remedies, and prevention, rather than actual experience with them. Until recently little attention has been given to prevention, and the usual attitude of the engineer, upon whom the main reliance for prevention ultimately must devolve, has been to let "sleeping dogs lie" or, more definitely, to "let well enough alone." However, the "laissez faire" attitude no longer is tenable, and in the past few years numerous conditions have caused those engaged in industry, including mining, to bring the subject before the public with a view to ascertaining the facts upon which to formulate remedial measures, primarily preventive.

Jan 1, 1935

Collaboration between education providers is the key to long-term sustainability and improved quality in mining education. The mining industry is now, more than ever, an industry doing business on a global basis. Staff are recruited by global mining companies in many different countries and can find themselves deployed anywhere in the world. The mining engineer of tomorrow must be willing to take on this international challenge, and must be educated to a level where he or she has a comprehensive grounding in technical aspects of mining engineering, but also a well-founded appreciation of management, social, environmental and cultural issues that may be encountered around the world. In order to deliver such an education, academic providers must collaborate at both a national and international level. This paper provides an overview of progress that has been made in Australia through the national joint venture ? Min¬ing Education Australia (MEA). Supported by the mining industry in Australia, through the Minerals Council of Australia (MCA), MEA has been operational since 2007 and is seeing the development of a range of innovative courses and delivery methods, together with a high level of staff cooperation across the country. MEA has also commenced some international teaching initiatives that are seen as a catalyst for a far greater degree of international collaboration in the future. Such activity is not only to the benefit of the students who are taught by experts from around the world, but it also ensures that individual univer¬sity programs remain viable in terms of staffing numbers and financial performance. The paper also presents some statistics on recent upward trends in mining engineering student numbers from around the world, in response to the global shortage of mining engineers.

Jan 2, 2010

By R. L. Brown

This report, summarizing the Bureau of Mines research and technologic work on coal and coal products for the period July 1, 1950, to July 1, 1951, is based largely on publications issued during the year. The sixteenth in an annual series, it gives footnote references to publications giving further details of the research and technologic work described, except in a few cases where research data presented herein has not been published previously. During the year, the national fuels situation was generally one of plentiful supply.3/ Mineral-fuel resources appeared adequate for several hundred years at reasonably increasing rates of supply. Coal-production capacity was in excess of demand; petroleum supplies were adequate; and natural gas use was limited only by pipeline capacity. However, it was pointed out that a world war would drastically change this situation of relative plenty, particularly with regard to supplies of petroleum and its products. Conversion to the use of coal on a large scale would be required, and improved methods of mining and of processing and using coal in solid or fluidized form or converted to liquid fuels could materially contribute to our national safety.

Jan 1, 1952

By Richard A. Forth

During the construction of the Island Line (ISL) in Hong Kong between 1982 and 1986 piled foundations of a building were encountered in a tunnel drive. As the tunnel alignment could not be changed work was temporarily suspended whilst grouting took place beneath the pile cap. The tips of the piles were then cut off. The normal precast concrete lining segments were replaced by the "stiffer" spheroidal graphite iron segments and tunnelling resumed. Settlement of the building was found to be under 10 mm due to the tunnel drive and no damage was reported to the building.

Jan 1, 2002

By W. L. Cornell

The Missouri lead ores are the only domestic sources of cobalt presently being mined and processed for other materials. They represent the best short-term solution for meeting up to 13 pct of the Nation's strategic and critical cobalt needs from domestic sources. Presently, the cobalt is lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minium impact on present production does not exist. This paper presents results of research, built upon earlier Bureau of Mines laboratory research, to enumerate the problems encountered in cobalt recovery from the copper concentrate under actual mill conditions; to present alternative solutions to these problems; and finally, to describe the best available technology for cobalt recovery within the imposed constraints. Mineralogical analyses showed the cobalt present as a distinct mineral phase, predominately siegenite, amenable to a physical separation method such as froth flotation. Flotation was chosen for recovery because of easy adaptation by the mills. Unit processes of grinding, conditioning, and flotation were studied individually and in concert, and a series of continuous tests were run based on the parameters developed to obtain engineering data for subsequent economic analysis. Overall cobalt grades of 3.00 wt pct at a recovery of 64.0 pct were achieved.

Jan 1, 1987

By R. B. Alke

Request to Mine Beneath Bridge The Jabs Run Bridge is a reinforced portland concrete arch filled bridge located on WV Bouts 7 near Pentress, WV. The bridge has a span of 22.9 m (meters) and a height of 4 m above normal pool elevation to the underside of the center of the arch (See Pig 1). The bridge is a two lane structure with a width of 6.86 m. The structure is over 50 years old Wing been built in 1929 and is owned by the Department (WV Department of Highways).

Jan 1, 1984

By Stanton L. Tainter

As a part of a wartime program to aid in the development of known ore bodies and in the discovery of hitherto unknown deposits of strategic minerals, the Bureau of Mines investigated the feasibility of diamond-drilling the Christmas copper deposit, in Gila County, Ariz., to increase the reserves of milling ore. Upon recommendation of the examining engineer, drilling was begun in September 1942, from the bottom (770) level of the mine. One month later, in cooperation with the Bureau, the Federal Geological Survey started geologic mapping of the mine workings. Since extensive and costly development would be required, the War Production Board concluded that ore below the bottom level could not be mined at that time because of the wartime shortages of equipment and man-power. In January 1943, drilling was moved to the 300 and 400 levels to locate reserves readily accessible for continued production of fluxing ore. This drilling, which was under the supervision of L. G. Marshall, was completed in January 1944.

Jan 1, 1948