Search Documents

By Jonathan Peck, Doug Pollitt, Malcolm Scoble

Over the past 5 years the Department of Mining and Metallurgical Engineering, McGill University, has been involved in the performance monitoring of both percussive and rotary drills. Studies conducted in open pit coal and iron ore mines using microprocessor-based research and commercially available instrumentation resulted in the monitoring of at least 6 performance parameters while drilling vertical production blastholes.

Jan 1, 1991

"In mineral exploration and mining applications, it is sometimes necessary to reduce sampling error in order to improve representivity of individual sample assays. Historic efforts to reduce sampling error have relied on the belief that larger samples exhibit less sampling error. Justifications for this belief traditionally have coupled the binomial theorem with an ideal geological material consisting of ore and gangue particles of equal size and shape (an equant grain model) and empirical tests of geological materials, to illustrate an inverse relationship between sample size and sampling variance. To date, no proof exists of this sample size-sampling variance relationship in real geological materials exhibiting variations in grain size, shape, composition, and degree of liberation.Using first principles calculus and the formula for the mean, sample mass and sampling variance are proven to be inversely proportional in all geological materials. Distribution assumptions and physically ideal geological models are not used in this proof. Furthermore, algebraic manipulations of expressions describing the variances of equant grain models consistent with binomial, hypergeometric, and Poisson distributions reveal that these models also exhibit an inverse sample size-sampling variance relationship. Thus, the sampling behaviors of these models are numerically consistent with the sampling behaviors of real geological materials, and these models can be used to estimate sampling errors in real geological materials using simple sampling parameters."

Jan 1, 2007

By Paul J. Axtell

Self-hardening cement-bentontie (c-b) slurry walls were constructed as shear walls to stabilize the downstream slope of Tuttle Creek Dam near Manhattan, Kansas. The slope stabilization was required to protect the existing pressure relief well system located at the downstream toe of the dam. The wells require protection from slope deformation induced by liquefaction of the foundation sands during or immediately after the design seismic event. The shear walls are transverse to the axis of the dam, unreinforced, and relatively brittle members that may be exposed to relatively large shear strains, and possible cracking, during or immediately after shaking. An extensive laboratory investigation was conducted on recovered core samples to optimize the mix design and stabilization scheme. Furthermore, as is the topic of this paper, a portion of the laboratory investigation was to determine the large-strain, or post-peak, shear strength of the c-b material for use in limit-equilibrium slope stability analyses and numerical deformation modeling to assess the magnitude of permanent deformation caused by the design earthquake. These data may be beneficial to other projects that are considering the use of unreinforced c-b slurry walls for seismic retrofit purposes.

Jan 1, 2010

By Patrick J. Hannigan

A comparison of 40 statically and dynamically load tested piles was performed to evaluate the variation between testing methods. This evaluation indicated an agreement of 10% to 15% could be obtained when the available static resistance is fully mobilized by both methods and when time dependent capacity changes are minimized. Dynamic pile testing recommendations for minimum induced impact force, ram weight to pile weight ratio, and considerations for time dependent capacity changes are presented.

Jan 1, 1987

Jan 1, 1992

By P. H. Morris

To achieve the full potential of sub-aerial co-disposal the properties of the co-disposed wastes must be known and understood. A description is given of the morphology and properties of waste deposits that were formed during 19 field trials of sub-aerial co-disposal at the dual Goonyella-Riverside mine in Queensland and at Hunter Valley No.1 and Warkworth mines in New South Wales

Jun 19, 1905

By A. J. Farstad

Recent advances in microcomputer technology have opened the way for systems which can track the location of underground mining personnel from the surface. A computerized system has been designed which is capable of not only tracking the location of the miner but also of monitoring underground parameters, communicating between work stations and sounding alarms when underground conditions are judged to be unsafe. For the system described herein, the locations of the underground personnel are detected by a network of underground terminals which routinely emit RF pulses to interrogate miniature transponders worn by the miners. Each transponder is uniquely programmed to delay its response in such a way that the RF terminal can identify the individual transponders by the time slots in which the responding pulses are received. The underground terminals are then interrogated by the host computer on the surface which keeps a running account on underground mine conditions and personnel. The underground portion of the system is designed to operate even during mine emergencies, deriving its power from rechargeable battery supplies which are float charged during normal operation. Nine mines were visited on this program and the industry reaction to the system was generally favorable. By slanting the system design for daily use in the mine, the chance of its acceptance by the industry is enhanced. Furthermore its likelihood of being operational in the event of an emergency is significantly increased.

Jan 1, 1981

By Mark Aylmore, Guy Deschenes

"Increasing pressure are motivating the gold mining industry to develop a substitute to cyanide for leaching gold. This effort in mainly based on the high toxicity of cyanide and on the lack of efficiency of cyanide in the treatment of mildly refractory gold ores (sulfides and pre-robbing). Consequently, in only a few years, consortia have been created to elucidate and implement a new technology. The most promising lixiviant that has been selected to replace cyanide is thiosulfate. This paper will present a critical analysis on the latest developments in thiosulfate leaching and illustrate the potential and limitations of the technology with experimental data. Finally an assessment of the cost and performance of thiosulfate leaching relative cyanidation will be evaluated.INTRODUCTIONConcerns regarding the toxicity of cyanide and inability of cyanide solution to effectively leach some carbonaceous gold ore or mild refractory gold ores have made the gold mining industry evaluate alternative lixiviants to leach gold. This concern has been heightened recently by the cyanide spill at a mine in Romania, which devastated a 250-mile stretch of the Danube River and its tributaries, and the environmental damage at Ok Tedi mine in Papua New Guinea. Some countries and locations have prohibited the application of cyanidation to recover gold, such as, California and Colorado States, Japan and Turkey etc.There are several potential non-cyanide lixiviants (Sparrow and Woodcock, 1995) for gold extraction, such as thiosulfate, thiourea and halogen. A pilot feasibility test (Marchant and Broughton, 1987) had suggested that thioureation might result in acutely toxic byproducts even after treatment. Scientists of Swedish Academic of Sciences reported that thiourea is a carcinogen. Halogen is also a pollutant to the environment. Thiosulfate leaching appears to have very good potential as an effective and less hazardous procedure for gold and silver extraction from auriferous ores. In addition to being much less toxic and relatively cheap, it forms a stable anionic complex with gold but is less reactive to other metals, for instances, copper and carbonaceous materials, in comparison with cyanide."

Jan 1, 2001

By Jan Pru?ka

This paper describes the sheet pile design for the Line C extension from Ládví station to the North of Prague. The first part of the paper describes the geological conditions and structural configuration of the project. Typical cross sections, the description of the construction stages, and monitoring are discussed. The second part of the paper focuses on the sheeting design method. It describes the method of dependent pressures, that is, how the pressures acting upon a structure depend on the deformation. The design process and verification methodology are described in detail with comparison of the results with in-situ monitoring.

Jan 1, 2011

By Eddine Chafika

El presente texto señala las diversas etapas de la exploración de Bear Creek Mining Corporation y su influencia en crear las condiciones para que las comunidades apoyen una mina, donde el resultado previsto de las relaciones comunitarias en las etapas de la exploración y minería, es el impacto sostenible y constructivo cuando el trabajo termine, no importa cuánto tiempo dure esto.

Sep 9, 2007

By G. L. Mowrey, S. D. Maksimovic

An important element of the U.S. Bureau of Mines (USBM) mining research program is the development and evaluation of reliable coal interface detection (CID) systems. Commercially available CID sensors based on natural gamma radiation (NGR) are only applicable if the immediate roof is composed of shaley material. The USBM has made numerous underground and laboratory measurements using several NGR systems approved for installation on mining machines by the Mine Safety and Health Administration. In addition, two small handheld NGR instruments were used to make comparative measurements. Underground NGR measurements in 10 different coal seams, potassium-uranium-thorium radiometric analyses on samples from 16 seams, and chemical analyses of coal and rock for correlation with NGR counts were made. Laboratory test results on the effect of air gap and sample thickness, size, and weight on the NGR measurements, as well as general results of the various NGR systems, are discussed.

Jan 1, 1995

By Berny Rivera

The paper point out the Galvanox process developed at the University of British to leach concentrates containing copper sulfide mixtures, mainly chalcopyrite. This patented process is based primarily on the galvanic interaction between chalcopyrite and pyrite, which allows chalcopyrite to be leached preferentially over pyrite. Under the correct process conditions, near-complete extraction of copper can be reached typically within twelve hours. This study will also show that this process is suitable to treat low grade copper concentrates (bulk concentrates) taking advantage of the selectively of chalcopyrite over pyrite, and the use of pyrite as a catalyst.

Sep 9, 2007

By A. B. Cecala

A few years ago, the National Institute for Occupational Safety and Health and Unimin Corporation developed a clothes cleaning system that is able to quickly, effectively, and safely remove dust from a worker?s clothing without dust exposure to the worker, the work environment, or co-workers during the cleaning process. To perform the process, a worker enters a cleaning booth and activates an air spray manifold which blows the dust from the worker?s clothing. Since the cleaning booth is under negative pressure, all the dust and product removed are contained. In the original design, this dust-laden air was exhausted to a dust collector system. However, since most operations do not have excess dust collector capacity, it was decided to determine an alternative method to provide for a stand-alone cleaning system. This was achieved by ducting the exhaust outside the plant and into the atmosphere. This technique was recently tested and shown to be a viable method to provide for a stand-alone clothes cleaning system.

Jan 1, 2009

By Shadia J. Ikhmayies

The SnO2/CdS/CdTe thin film solar cells were fabricated on glass substrates by using the spray pyrolysis (SP) technique for the deposition of the SnO2 and CdS layers and vacuum evaporation for the CdTe layer. The transmittance curves were used to investigate the interdiffusion in the two interfacial regions SnO2/CdS and CdS/CdTe by taking the first derivative of the absorbance as a function of wavelength. The appearance of new bandgaps around the bandgaps of SnO2:F, CdS:In and CdTe layers is a strong evidence on the interdiffusion in the two interfacial regions and/or the formation of quantum dots.

Jan 1, 2010

The physical setting and background to mining operations on Misima Island and the overall plant lay-out are outlined. Developments and changes made to each section of the plant are described as they were encountered during commissioning and initial operation.

Jan 1, 1991

By Mehmet Guney

At the Armatcuk mine in Turkey, various modifications of sublevel methods have been tried during the last decade in an effort to eliminate gob fires, dangers from roof falls, and surface subsidence, and also to increase extraction efficiency. From the experience thus gained, it was decided that the most likely system to give maximum benefits, considering the existing geological conditions and coa1-seam characteristics, was hydraulic stowing. This paper examines trends in the working techniques of hydraulic stowing and discusses the favorable results and technical problems that the method produced at Armutcuk. The Armutcuk mine, a subsidiary of Eregli Coal Mines (EKI), produces 1300 tons of run-of-mine coal daily from thick (about 10-90 ft) and highly dipping (about 50-90°) coal seams. The coal is highly volatile with good coking properties that make it highly suitable for industrial use. Most of this coal is used in the iron and steel industry at Eregli on the Black Sea coast. Complete recovery of the coal is of vital importance to industrial development and progress. Initial coal extraction was carried out by means of a sublevel mining system modified to accommodate local geological conditions and coal seam characteristics. This method is similar to that employed in metalliferous mines. Several problems arose from the application of the method, one of them being the prevalence of gob fires which caused periodic shutdowns in some sections. To achieve maximum coal extraction with minimum dilution, to eliminate gob fires and surface subsidence, and to reduce fatal accident rates, a decision was taken to change from this method to a hydraulic stowing system. The pres- ence of large deposits of conglomerate and sandstone on the surface contributed to the decision to employ this new method. Although hydraulic stowing practices have been carried out in America and Germany, Upper Silesia may, so far as coal is concerned, be considered the birthplace of the method. Here the process was adapted to thick coal seams on a large scale to reduce dangers from gob fires and damage from surface subsidence. Today, the mining system is not only widely used in the coal mines of France, the Saar, India and Poland, but has also been successfully applied to the iron ore and potassium salt mines in Russia and Germany. LOCATION AND HISTORY The Kandilli-Armutcuk coal field, the most western outcrop of the North Anatolian coal basin, extends for five miles along the Black Sea coast (Fig. 1). The Armutcuk Mine is situated on the southern boundary of the coal field about 40 miles from Zonguldak and about 12 miles from Eregli. The history of coal mining in the North Anatolian coal basin goes back more than a century. Mining commenced on a small scale in the Kandilli-Armutcuk coal field in the late 1880's, and from this time until nationalization in 1940 the mines were operated by private Turkish and foreign interests. In 1940, Eregli Coal Mines was established to takeover the management of these enterprises. The Armutcuk Mine was developed for the first time in the mid-1940's. Since then it has been in continuous production and it now produces an annual 440,000-ton run-of-mine output from which 320.000 tons of salable coal is obtained. MINE GEOLOGY The carboniferous inlier of the Kandilli-Armutcuk coal field crops out over an area about three miles long and one mile wide. The major part of the inlier consists of the Namurian formation with only a relatively small area of Westfalian-A visible on the surface (Fig. 2). The Namurian formation, which has no exploitable coal seams in the Armutcuk Mine, consists mostly of arkose sandstones and black shales often having

Jan 1, 1969

Jan 1, 1963

THE art of mine surveying has made very great progress in recent years, and is still advancing, perhaps faster than any other branch of surveying. The scope of the mine surveyor's duties has greatly increased, his instruments and methods have improved, the responsibility of his position is greater, and the end is not yet in sight.It might be supposed that such a steadily growing subject would have an adequate literature, but this is by no means the case and outsiders commonly judge mine surveyors by their text-books. Hardly any condemnation can be too strong for most of these books. The English books truckle to the antiquated and crude methods apparently still in use in England, and thereby largely aid in perpetuating them; they commonly in illustrative examples give the distances in fathoms, feet, and inches; they spend page after page discoursing on instruments that should have been forgotten long ago; they try to antagonize theory and practice by detailing such calculations as that a certain vein will contain 2,003.907 pounds of galena per square fathom, and then reduce this amazing quantity to hundredweights, quarters, and pounds. Nothing can be more unscientific, or, for that matter, less businesslike, than unwarranted assumptions of accuracy; it is, perhaps, the greatest curse of applied science. Here we have a calculation to thethousandth part of a pound, when there is probably an unavoidable error of two hundred pounds. What shall we say of a man who explains how to measure the depths of shafts to the hundredth part of an inch by means of short brass rods screwed together...

Jan 1, 1909

By Fred Pena

Cyprus Pima Mining Company is located in the Mineral Hill District of southern Arizona, approximately 22 miles south-southeast of Tucson. Cyprus Pima Mining Company is owned 50.01% by Cyprus Mines Corporation, 24.99% by Utah International Incorporated, and 25% by Union Oil Company of California, with Cyprus having the management responsibility. Cyprus Pima's history has been one of continued expansion from an initial plant of 3,000 TPD in 1957; 6,000 TPD in 1963; 18,000 TPD in 1966; 36,000 TPD in 1967; and 53,500 TPD in 1972. The major reason for Expansion IV was that a large volume of low-grade ore had to be moved to get at a higher grade ore in the course of proper pit development. With mining costs already defrayed, this relatively hard, low-grade material became economically profitable for subsequent milling and concentrating treatment. Similar material previously stockpiled was available for ore treatment. In an effort to meet the continuing search for lower unit costs, the largest milling and concentrating equipment had to be examined. The management of Cyprus Pima Mining Company began investigating autogenous, and semi-autogenous milling in 1964 when two carloads of ore selected from the Cyprus Pima pit were sent to the Koppers--Hardinge Operation at York, Pennsylvania for testing. One car contained approximately 40 tons of hard arkosite and the other contained approximately 40 tons of ore classified as soft Hornfels. The purpose of the testing was to determine the amenability of both ore types to autogenous or semi-autogenous grinding.

Jan 1, 1974

By L. J. Heaslip, J. M. Toguri, T. R. Meadowcroft, R. L. Addinall

"""Pilot Plant Operations"" is a final-year core course given to the Metallurgy and Materials Science students at the University of Toronto. This course involves a laboratory study of an industrial project at an industrial site. Details of this program are discussed and reviewed after eight years of experience. IntroductionEducators in the field of Metallurgy and Materials Science have long agreed that ""hands-on"" experience is an important component in the education of metallurgical engineers. This philosophy is reflected in the undergraduate curricula of most metallurgical schools. The major problems encountered with laboratory-associated courses are the requirements for equipment, space and funds for both purchase and maintenance of equipment. For example, consider an exercise in crushing and grinding treatment in a mineral processing laboratory. Such operations require the handling of tons of material and often equipment of large size. The problems of storage of ore, methods of handling and maintenance of equipment are a few of the concerns facing the department. Considering that metallurgical departments at universities are, in general, relatively small, the support to purchase and maintain largescale equipment becomes an annual budgetary concern. In reality, universities today are not geared to operate mini-pilot plant equipment, either in terms of space or personnel.For the above reasons, in 1972an undergraduate core course called ""Pilot Plant Operations"" was introduced to the fourth year curriculum in Metallurgy and Materials Science at the University of Toronto. This course consists of I to 2 full weeks (8 hrs per day) of pilot plant laboratory study at an industrial site on a project of mutual interest with the industrial organization whose facility is being used. The first 5 years of the program were carried out at the pilot plant facility at the Ontario Research Foundation; Stelco's Research Centre in Burlington, Ontario, was used for the last 3 years. The nature of the projects undertaken during the 8-year period is shown in Table 1."

Jan 1, 1980