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By H. A. Bilgin, G. G. U. Aldas

"Ground vibration is the natural result of the blasting process. Many empirical formulae and methodologies including analysis of travel path effects have been developed. The scaled distance, which is the most popular approach for the calculation of the attenuation of particle velocity in the ground, has led to significant advances in the prediction of particle velocity when both explosive charge and distance vary. However, this approach does not consider the effect of ground anisotropy and existence of structural geological features on ground vibration. Therefore, in this study, the effects of these rock mass properties on types, amplitudes, and frequencies of ground vibration waves at four surface mines are examined. The results, which were implemented at Kangal coal mine, Bastas quarry and Kíbrís quarry, provided guidance for the extensive study at Orhaneli surface coal mine.As a result of the study, the authors came to the conclusion that vibration amplitudes change depending on the ground on which sensors were deployed and the conditions depending on whether measurements were done near major structural geological features. It was determined that the vibration amplitudes, measured at equal distances from the source but in different directions, change because of the propagation velocity anisotropy. Besides the change of wave type due to the kind of ground at the measurement location, it was determined that vibration anomolies were due to structural features."

Jan 1, 2004

By Laura McNally

In 2006 McNally International Inc. in a Joint Venture partnership with Aecon Constructors was the successful bidder on two York Region Tunnel Projects: Bathurst Collector/Langstaff Trunk Sewers; and YDSS Interceptor Sewer 19th Avenue Project. These projects comprise a total of 13 kilometres of 2.74 meter finished diameter tunnels and are both part of the York Durham Sewer System (YDSS). Both contracts require the use of EPB tunnel boring machines with a precast concrete segmental liner. The following provides an overview the two projects.

Jan 1, 2008

By J L. Carpenter, S M. Iveson, K P. Galvin

Wet beneficiation of iron ore fines less than 1 mm typically involves a desliming stage ahead of the fine gravity separation such as spirals. The desliming is achieved using a bank of cyclones. The reject ultra-fines emerge in the overflow stream at relatively low pulp density, contain high proportions of low-value slimes, but also well-liberated iron ore ultra-fines below 0.045 mm in size; however, recovering the valuable iron ore ultra-fines from this overflow stream presents a significant challenge due to the need to remove such a large amount of water and slimes.The REFLUX™ Graviton consists of distinct 3D-printed modular units, based on REFLUX™ Classifiers, which are rotated at high speed in a large centrifuge. This system has previously been investigated under semi-batch conditions, demonstrating the potential for precision separations with significant capacity. It has been shown that the throughput advantage of the inclined channels and G forces multiply. This is the first paper presented showing the performance of this system under continuous steady-state conditions. Ultra-fine silica in the size range of 0 to 0.045 mm was fed to the Graviton at different volumetric rates, fluidisation rates and pulp densities ranging from 2 wt per cent to 30 wt per cent, in order to develop a fundamental understanding of the system’s performance. Experiments were then repeated using ultra-fine iron ore.CITATION:Carpenter, J L, Iveson, S M and Galvin, K P, 2017. Separation of ultra-fine particles using the REFLUX™ Graviton, in Proceedings Iron Ore 2017, pp 141–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Sam Ammermann, William Heasley

"The mining industry is on an ever accelerating path to complete mechanization. As companiesutilize more sophisticated and efficient methods of blasting, a more thorough look should begiven to the pros and cons of mechanized shaft sinking. Historically, Vertical Shaft SinkingMachines (VSSM) have been capital intensive, making it hard to enter lowest bidder marketssuch as the United States. As advances in safety and technology have occurred, VSSM methodsare becoming increasingly common in many countries outside the United States. Decreasedcapital requirements, a greater amount of competition within the VSSM market along withgreatly improved safety practices, have made it more competitive with traditional drill and blast(D&B) methods. However, VSSM technology has yet to be embraced by the United States. Alarge culture shift will have to occur before VSSM technology will become common in theUnited States. The history, and advent, of raised boring machines will be discussed and how itrelates to the current development of VSSM technology. The researchers will analyze the uniquerisks of D&B methods and how they compare with the unique risks of VSSM technology. Theresearchers will put an emphasis on risks directly affecting the safety of personnel working onthe shaft sinking operation. Many of these risks are identified by contracting companies withregards to geology, relative location of resources and the chosen shaft sinking method. Theresearchers will discuss specific risks a given shaft sinking company will want to consider whenchoosing between D&B and VSSM methods."

Jan 1, 2016

By C. Legote

"This paper investigates the conditions leading to the indefinite termination of production in four critical primary panels at an underground coal mining operation, the observed shortcomings in the mining approach, and the proposed strategy to mine through the affected panels. Initial assessment of the abandoned panel conditions indicated time-dependent strata failure,(i.e. bolted roof failure overrunning intersections), which occurred from mere minutes to up to four weeks post-production, with and without prior warning of failure. This prompted the constant re-supporting of back areas, which raised safety and productivity concerns. Investigation of the initial mining conditions revealed that the failures were due to a critical combination of factors, the chief of which was isolated horizontal stress. Other factors that were initially overlooked by the mine (i.e. influence of hydraulic stress, misinterpretation of borehole data), resulted in the conditions being described as abnormal. Remedial actions were determined, and in so doing, a new strategic approach was formulated to thoroughly address all failure concerns. The four panels were explicitly planned to serve as the main intake and return airways for the recently commissioned secondary ventilation shaft, as well as providing access to millions of tons in proven coal reserves. It is thus imperative to mine the panels. A feasibility study showed that the proposed strategy set for implementation would be financially viable. Paper written as project work carried out in partial fulfilment for BEng(Mining Engineering) degree"

Jan 1, 2015

By Arthur L. Murray

"INTRODUCTION In compliance with those provisions of the organic act establishing the Bureau. of Mines which relate to improvement of health conditions of persons engaged in the mining, preparation, or treatment of mineral substances, sanitary surveys have been made of towns and villages housing the coal miners, metal miners, and mill and smelter employees of Utah.The purpose of the surveys is to afford studies of conditions prevailing in the various mining and smelter towns so far as concerns housing, water supplies, sewage disposal, refuse disposal the handling of foodstuffs, general sanitation, wash and. change houses, and the control of preventable diseases, all of which directly or indirectly have a bearing on the health and efficiency of employees and their families. Certain other factors have been added to the general sanitary surveys such as school and recreational facilities, which have a decided influence on contentment and efficiency. Through comparisons of favorable and unfavorable conditions and practices, and the dissemination of such information, improvements can be effected which will benefit both the employees and the employers.ACKNOWLEGMENTSAcknowledgment is made of the many courtesies shown by the officials of companies and towns visited. In some instances the towns were entirely under the control of officials of mining companies, being on company property whereas, in other instances, the towns wars incorporated not under company management. Particular acknowledgment is made of the assistance given by the Utah State Board of Health through Health Commissioner Dr. T. B. Beatty."

Oct 1, 1932

By P. Hickey, J. Spenceley, T. J. DeMull

Development of the Batu Hijau Project was successfully completed in the fourth quarter of 1999 with the final handover and start-up of ore processing facilities. The development project had started more than three years earlier, in August 1996, when the Owner, PT. Newmont Nusa Tenggara (PTNNT), awarded an EPC contract to Fluor Daniel (FD) for design and construction of the project including: copper concentrator, port, power plant, town site, and infrastructure. PTNNT managed the development of the mine and procurement of mine equipment with its own forces. Bringing the Batu Hijau copper deposit into production was the largest mining project ever undertaken. Development of Batu Hijau was a complex project involving the work of tens of thousands of people in all parts of the world to complete engineering, manufacture and deliver equipment, supply materials, and build the plant. The ore deposit is located on the tropical island of Sumbawa in a remote and undeveloped section of Indonesia. The location and environment presented challenges for all phases and aspects of the project. To meet the challenges, the project team combined good planning and teamwork to best utilize the resources available. This approach assured continuity of personnel through construction to operations and minimized cost, resulting in completion of the project ahead of schedule and under budget.

Jan 1, 2001

By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994

The upper amphibolite-grade mctasediments of thc rinaroo area, North Queensland, form part of a regional aurcole to the large Tinaroo Batholith and are the stratigraphic equivalents of the Hodgkinson Formation of gencrally low metamorphic grade. There is no evidence of any lithological unconformity.The higher grade metasediments have a more complex deformation history than is typical for thc surrounding region and this may bc due to one or a combination of two factors; an additional strain componcnt associated wilh the intrusion of Ihe Tinaroo Batholith, or a more marked finite strain response to the overall regional stress field within hotter. more ductile rocks.Four deformational events can be characterized within Ihc Tinaroo Area. Close to Ihe Tinaroo Batholith D1 and D2, arc so strongly developed that they disrupl the continuily of Ihe original Iithological layering. In the aureole region, D1 is strongly overprinted and its original fabric intensity is obscured, but both D2 and D3 display a mappable decrease in intensity away from the granite margin. These three deformations occurred during Carboniferous or early Permian time. D4 is later and only patchily developed.The broad, moderate pressure metamorphic aureole surrounding the Tinaroo Batholith is a typical of the CairnsCooktown group of Permo-Carboniferous granitoids. which usually develop narrow, lower pressure contact aureoles. Two periods of metamorphism are distinguishable. The first reached peak temperatures somewhat greater than 520°C, the second temperatures around 620-630° C immediately adjacent to the granite contact.Several cale-silicate lenses containing scattered scheelite mineralization occur within the area. Scheelite appears to have crystallized at the same time as the cale-silicate minerals, its appearance coinciding with the intrusion of the Tinaroo Batholith. Unlike many "skarn-type" scheelite deposits, the scheelite-bearing cale-silicates are Fe-poor, with no positive correlation between total Fe and W.

Jan 1, 1982

CENTRAL mine ore consists mainly of galena and marmatite in a siliceous and rhodonitic gangue, the average assay values being approximately 11.5 oz. per ton Ag, 14.5% Pb, 14.5% Zn, 1.3% Ox Pb, 0.3% Ox Zn.Owing to the 1923 fire in the underground workings, much of the ore now being mined has been subjected to a certain amount of oxidation, as shown by the oxidised values above.This factor is of great importance from a flotation point of view, as a sulphide surface which has been subjected to the influence of oxidation is not as amenable to flotation concentration as a fresh sulphide surface. The importance of this factor is increased when a differential flotation is to be made, and, as in the case of Central mine ore, the sulphide, which is to be floated first, has been oxidised...

Jan 1, 1931

By M. Yavuz, M. Aksoy, G. Once, M. Iphar

This paper is concerned with a study on the floor heaving in the transport road of the GLI Omerler Colliery in Tuncbilek-Turkey. This gallery has been opened at the depth of 200 m through the formation of marl in 4.6 m width and 3.5 m height in cross section. Floor heaving occurred up to 70 cm in height in maximum and caused severe problems in railway and band-conveyor transportation in the main road. In addition; after the current panel mined out, the shield support units could not be transferred to the new panel because of the deformation of roadway cross-section. The I-profile steel arch supports also sank into the weak floor rock. This situation has been studied by numerical analysis using the FLAC3Dfinite difference program in order to investigate the rock mass behaviour around the opening. The obtained outputs of the numerical model have showed consistency with the amount of floor heaving in the gallery at 200 m depth. A new gallery has been driven at the depth of 115 m and M4 longwall panel has just been taken to production. So as not to encounter with the same problems at 200 m depth, especially longwall face moving problem, various numerical models have been studied in order to keep the floor heaving in the acceptable limits required to move shield support units. Keywords: Floor heave, Numerical modelling, FLAC3D, Failure criteria, RocLab

Jan 1, 2003

By H. Yilmaz

A testing method for assessing the shear-bond strength of thin spray-on liner (TSL) on rock substrate was developed at Wits University Rock Mechanics Laboratories. The gap between a 20 mm thick steel ring and a rock core is filled with TSL along the depth of the ring. After the curing of the TSL for a predetermined period, the sample is placed on a base, which offers support to the steel ring and the TSL but not to the rock core. A compressive load is applied on the rock core displacing the core on TSL contact and punching it towards the void in the support base. Shear-bond strengths for different TSL products as well as shotcrete were measured. This paper describes the test set-up and points out the important aspects and procedures during sample preparation and test execution. The test results are also presented and discussed.

Jan 1, 2007

By Rees J. Llewellyn

Improved product development, assessment methods and evaluation studies of materials for oil sands applications have traditionally focused on low and high stress abrasion and slurry erosion resistance mechanisms, because they were considered to be the predominant wear modes prevailing in oil sands mining, transportation and bitumen recovery. More recently with the very successful introduction of oil sands hydraulic transportation systems, there has been increasing use of crusher systems in which materials of construction are also required to have good toughness and gouging abrasion properties to withstand impact and the severe indentation and ploughing forces that are involved. To assess material property requirements for mitigating this additional wear mechanism, jaw crusher gouging abrasion tests using a modified ASTM G81 procedure, have been carried out on a range of wear materials of interest for oil sands mining service. The method involves a comparison of the wear losses that occur for reference and selected test plates when a controlled amount of standard feed rock is comminuted in a laboratory jaw crusher. Among the classes of material evaluated have been Q&T plate steels, austenitic manganese steel, chromium and chromium molybdenum white irons as plain castings and in laminated forms and also chromium carbide and tungsten carbide overlaid wear plates.

May 1, 2004

By Lewis Stansfield

A rotary displacement method was used to install permanent steel casings for bored piles through an asbestos tip. This method was chosen in preference to alternative driven systems because it was quieter and more versatile if obstructions were encountered. New equipment was designed and made specifically for the project, and stringent health and safety regulations had to be observed.

Jan 1, 2000

By Steven D. Wirch

Abandoned underground coal mine areas must either be sealed or ventilated to comply with federal mine regulations. Ventilation of these abandoned areas is often impractical due to roof falls and inadequate primary mine ventilation. If the area is sealed, a very complex ventilation system is set up. In which the gob "breathes" in and out due to barometric pressure fluctuations. The Gob Assistant is a computer program (for use on IBM compatible personal computers) which allows the prediction of air flows into and out of a sealed mine area. Gas flows with applicable control techniques are also modeled. This information is presented to the user who will decide which control technique, or combination of techniques will ultimately be applied. The Gob Assistant is an intelligent gob simulator that can reduce the guesswork involved in predicting the effects of sealing and control techniques before they are applied. This paper provides the fundamental principles upon which the Gob Assistant is based, verification of these principles, and an explanation of how these principles were integrated into the Gob Assistant.

Jan 1, 1988

By Franklin D. Cooper

This Bureau of Mines report reviews in detail the foundry coke situation in the United States in 1975. It discusses intrinsic production problems and identifies opportunities for modifying operating practices so that the quality and yield of foundry coke can be enhanced without unnecessary investment in new equipment. Major topics include operating data and attendant practices and problems, the relationship of carbonization phenomena to coke quality and yield, environ- mental impacts of foundry coke plant operations, suggested research and development opportunities, and data on components of oven charges and on foundry coke production and shipments.

Jan 1, 1977

By M. G. Zabetakis

This publication contains highlights of a 4-hour lecture and demonstration by the Bureau of Mines on the fire and explosion hazards of flammable liquids and solids, oxidizing materials, corrosive liquids, and compressed gases. The authors first presented this material as part of a 2-week course given to officers and enlisted men at the U.S. Coast Guard's Dangerous-Cargo Handling School, established at Fort Eustis, Va., in 1959. The Bureau was asked to present the lecture and demonstration because of the extensive experience of its researchers in handling certain harardous commodities.

Jan 1, 1961

By Michael Valencia, Alonso Marchena, Fredy Arcos, Miguel Chumbe

Cobrepampa es un depósito de cobre ubicado en Acarí (Caravelí-Arequipa). La mineralización se emplaza en pórfidos dioríticos pertenecientes al intrusivo Cobrepampa (Superunidad Linga) y está constituida por bornita, calcosina, covelina y calcopirita y en la zona de oxidación cuprita, crisocola, malaquita y hematita. El magmatismo es calcoalcalino con alto K. El intrusivo Cobrepampa evoluciona por fraccionamiento y contaminación en una corteza más delgada que la superunidad Linga. Petromineralógicamente se tiene epidotización con diseminaciones de calcopirita, pirita y bornita, gangas de cuarzo y calcita con hematita acicular. Las inclusiones fluidas muestran temperaturas de homogenización de 165.5 - 266.43 °C y salinidad 3.5 - 16.8 % eq. peso NaCl de un mesotermal o epitermal, pero que por sus características geomineralógicas sería un mesotermal. Por tanto, Cobrepampa presenta más de un evento de mineralización: una con magnetita y actinolita, y otro mesotermal de vetas de cuarzo con sulfuros.

May 22, 2019

By Lisa Morrison

The 11th Annual Mineral Economics and Management Society (MEMS) conference was held April10-12, 2002, in Montreal, Quebec. It consisted of a series of technical sessions. Each paper addressed the economic issues that are related to the changes that many people believe are now required in the mining industry. Some of the papers were directed at how the mining industry will handle the changes that will be required in its philosophy and operations management. Of equal importance was whether the industry possesses the toolkit necessary to effect these changes and emerge stronger from its challenges.

Jan 1, 2002

"The measurement of error in assays collected as part of a mineral exploration program or mining operation historically has been undertaken in a variety of ways. Different parameters have been used to describe the magnitude of relative error, and each of these parameters is related to the standard measure of relative error, the coefficient of variation. Calculation of the coefficient of variation can be undertaken in a variety of ways; however, only one produces unbiased estimates of measurement error: the root mean square coefficient of variation calculated from the individual coefficients of variation.Thompson and Howarth’s error analysis approach has also been used to describe measurement error. However, because this approach utilizes a regression line to describe error, it provides a substantially different measure of error than the root mean square coefficient of variation. Furthermore, because regression is used, Thompson and Howarth’s results should only be used for estimating error in individual samples, and not for describing the average error in a data set. As a result, Thompson and Howarth’s results should not be used to determine the magnitudes of component errors introduced during geochemical sampling, preparation, and analysis.Finally, the standard error on the coefficient of variation is derived, and it is shown that very poor estimates of relative error are obtained from duplicate data. As a result, geoscientists seeking to determine the average relative error in a data set should use a very large number of duplicate samples to make this estimate, particularly if the average relative error is large."

Jan 1, 2007