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By R. Emmett Hughlett

The Bureau of Mines has developed a statistical approach to the laboratory evaluation of response bias and precision in gas detectors. The techniques described employ a computerized analysis and a new method of data presentation called composite graphing. The underlying theory, its practical application to the data, and the experimental equipment and procedure are described.

Jan 1, 1982

By R. K. Linn

The New Idria Mining and Chemical Co. owns and operates the New Idria mine in southern San Benito County, Calif. During 1957-59, the New Idria mine was the largest producer of mercury in the United States and its alltime production of over a half-million flasks was exceeded only by one mine. It is one of the oldest and most consistent producers in California. With the exception of 1921-22, the mine has an annual production of mercury dating back to 1854. This paper by the Federal Bureau of Mines describes the exploration, development, mining, and furnacing of mercury ore at the New Idria mine. Figure 1 is a view of the furnace plant of the New Idria mine. The purpose of this report is to promote the development and conservation of our mineral resources by dissemination of technological information on mining and processing procedures, and related practices at operating mines.

Jan 1, 1961

By W. L. Connell, O&apos

The properties of some heavy liquids which can be used in sink-float separations are discussed with major emphasis being given to the halogenated hydrocarbons. Data are presented on density, viscosity, thermal characteristics and the effects of moisture and temperature on the corrosiveness of the liquids towards various materials of construction. The toxicity of these materials, the hazards involved in handling them, and the procedures for handling them safely are also discussed. True liquids have certain advantages over colloidal suspensions for sink-float separation of minerals which makes their use especially advantageous when close separations, fine particle sizes or water-soluble minerals are to be treated. For best separating results, the medium should have an easily controlled, uniform, stable density. Here, true liquids have the advantages of allowing closer control of density and of not requiring agitation to maintain a uniform den- sity in the equipment. Low viscosities are desired in a separating liquid so that rapid separations of fine material can be made. Many liquids have lower viscosities than the colloidal suspensions at operating gravities of 1.4 to 5.0. For economic reasons and to prevent contamination of the product, the separating medium must be easily and completely removed from the ore. Normally, true liquids must be more completely removed than the cheaper suspensions and thus cause more problems in this area. The fact that the medium should not react with the minerals, air, water or the common materials of construction limits the choice of liquids which can be used, but many are available which are sufficiently stable. A more serious objection to the use of true liquids is that many of them present a toxic hazard to operating personnel and users of the product. Most true liquids are toxic to some extent, but modem knowledge of toxicity allows us to recognize the hazards inherent in handling them and enables us to design around them. Three types of true liquids are available for this use: 1) Halogenated hydrocarbons cover the gravity range from 1.2 to 3.3. They are generally more volatile and less viscous than the other liquids.

Jan 1, 1963

By S. O. Bada

Coal samples taken from the No. 2 Seam and No. 4 Seam in a South African colliery were tested in a rotary triboelectrostatic separator. The two-stage triboelectrostatic separation results using the -177 µm size fraction reduced No. 2 Seam coal containing about 30.4 per cent ash to a clean product of 8.9 per cent and 13.1 per cent ash with combustible recoveries of 9.6 per cent and 30.7 per cent respectively. The same separation approach on No. 4 seam feed coal, which contained 36 per cent ash, produced a clean coal product with 10.8 per cent ash at a combustible recovery of 6.0 per cent. Petrographic tests show a significant improvement in the vitrinite content and a reduction in visible minerals encountered when using the triboelectrostatic separator, with about 53 per cent vitrinite reporting to the clean fraction for No. 2 Seam compared to the feed content of 21 per cent, and a 54 per cent vitrinite in the clean No. 4 Seam from a feed content of 21 per cent. Significant sulphur reductions were also observed after separation in both coal samples, with a better separation in the second-stage coal products.

Jan 1, 2012

By C. Dinis da Cama

In order to reduce the complexity of mechanisms influencing rock- fragmentation by blasting a simulation approach is proposed, using the capabilities of micro-computer interactive graphics. Situations involving cratering and bench blasting are simulated, and both jointed and intact rocks can be subjected to explosive action, taking into consideration its breakage mechanisms. Size analysis curves relating rock distribution before and after the blasts are determined and compared with field data.

Jan 1, 1984

By F. Essrich

A quantitative rockburst hazard assessment procedure was introduced on Elandsrand Gold Mine at the end of 1994. It is currently used to evaluate the seismicity-related risk in production areas on the mine. Six parameters related to seismicity, geology, mining layout, and production are rated and results are used as a planning tool on a regular basis. The applied assessment can be considered successful in that it promotes awareness of the seismic hazard and provides an opportunity to address seismicity-related mining problems. A comparison between high risk panels and those working areas with rockburst incidents showed that high hazard ratings reliably forecast the occurrence of larger events in the following month but they do not necessarily predict those working places with rockburst-related accidents. From this one may conclude that high levels of seismicity do not coincide with high rockburst rates.

Jan 1, 1997

By N Clarke, G R. Ballantyne, M S. Powell, P Elms, A Anyimadu

AngloGold Ashanti Ltd nominated Sunrise Dam Gold Mine as a case study via their involvement with the long-running Australian Mineral Industry Research Association (AMIRA) International P9P research program (AMIRA, 2015) . A group of researchers from the Global Comminution Collaborative (GCC) conducted a comminution circuit survey and review together with a large group of graduate metallurgists, senior metallurgists and operators. Fundamental and applied research understanding was used to identify productivity and efficiency improvements around the crushing and grinding circuits. The limitations of current scientific knowledge were identified through this process and this will allow future research to be more focussed on what is required by industry.The comminution circuit at Sunrise Dam comprises three stages of crushing followed by two stages of ball milling. The secondary crusher and primary ball mill classification were identified as the primary limitations of the circuit. The secondary crusher was found to be underperforming through overall equipment efficiency (OEE) analysis and an improved chamber design was identified by Chalmers University. This improved design will promote higher power utilisation, choke feeding and a finer crushed product for the milling circuit. The primary ball mill product is classified by a combination of a trommel, 3 sieve bends and a hydrocyclone. The combination of poor classification and coarse, competent feed led to a situation where the primary mill was overfilled with rocks, reducing grinding rate due to cushioning of impact. Size specific energy (SSE) benchmarking methodology was used to identify that a 10% increase in throughput could be achieved with improved primary classification.CITATION:Ballantyne, G R, Clarke, N, Elms, P, Anyimadu, A and Powell, M S, 2015. Application of research principles to identify process improvement at Sunrise Dam Gold Mine, in Proceedings MetPlant 2015, pp 221–229 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By H. Kinilakodi, R. L. Grayson

In 2010, the U.S. Mine Safety and Health Administration (MSHA) began holding hearings on a new coal mine respirable dust rule, which proposed a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the “hot spots” where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines’ compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, average mining height and selected “hot spot” counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications for the need for better dust control methods.

Jan 1, 2012

By John Babcock, Bryan C. Smith

In a partnership between Luck Stone Corporation and Loudoun Water, a 42” (1.067m) steel pipeline was constructed along the perimeter of an extensive permitted reserve of diabase rock Luck Stone was about to begin mining. Loudoun Water provides drinking water and wastewater services to over 75,000 households in Loudoun County, Virginia. In discussions to establish the 30-foot (9.1 meter) easement for Loudoun Water within the permitted reserve of diabase rock, Luck Stone and Loudoun Water agreed on the following basic conditions: • Luck Stone could execute production blasting as close to the easement as physical conditions of overburden depth permits. We estimated the minimum distance to be about 75-feet (22.86 meters) from the centerline of the pipe. • Loudoun Water would install strain gauges on the pipe every 500-feet (152.4 m) along the entire length of the future reserve area. This resulted in the installation of 18 strain gauges. • Luck Stone would contract a third-party vibration monitoring company, agreed to by Loudoun Water, to monitor the strain gauges and provide seismograph reading at appropriate locations along the pipe as mining progresses. All information would be provided to Loudoun Water. • Luck Stone’s blasting will be conducted in a manner that ensures the recommended strains are not exceeded.

Jan 1, 2019

By D. R. Corson

The Bureau of Mines instrumented an operating stope in a deep vein mine to determine the amount of wall closure and the magnitude of loads imposed on a backfilled stope. Hydraulic pressure cells used to monitor pressures in the fill) with bolt closure points to measure vein-wall movement and the procedure for their installation) are described) and the results of the laboratory calibration analysis of the reliability of these cells are given. An attempt to monitor density and moisture changes in the backfill with a nuclear density-moisture device was only partly successful) owing to either deformation of access tubing or relative displacements of the vertical vein walls relative to the emplaced tubes. Data from the instrumentation indicate vein-wall closure in excess of 20 inches and pressures within the fill approaching 600 psi. Analysis) incorporating field data with results of laboratory tests of the compressibility of timber and tests defining the constrained moduli of the fill) points out the limited restraint to vein closure offered by timber sets. Ground movement induced by mining activity could be more effectively con-trolled by the use of densely compacted backfill.

Jan 1, 1967

By Sara Jane Boles

In recent years the interest in rare-earth compounds as refractory materials has exceeded the available literature on the subject. While some basic properties, such as density and melting point, of the more readily available rare-earth compounds have been reported in the literature, relatively few papers can be found that deal comprehensively and primarily with high-temperature refractory properties and applications of rare-earth oxides, carbides, sulfides, and nitrides. Therefore, this bibliography has been pre-pared for the use of the ceramic industry as a guide for locating and utilizing the scattered and frequently fragmentary information available. The term "rare earths", as applied in the literature search for this bibliography, is understood to include the following elements: cerium, dysprosium, erbium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, samarium, terbium, thorium, thulium, uranium, and ytterbium. (On the periodic chart, these elements appear as numbers 57 through 60, 62 through 71, 90, and 92.) It is emphasized that many of the abstracts included are from papers in which the rare-earth compound or compounds are treated along with several other ceramic materials, are mentioned only secondarily, with primary interest placed on a more commonly used refractory material, or are used as part of a mixture of materials formed experimentally and reported on in the paper. As the better known rare-earth materials, such as the oxides of uranium, thorium, and cerium, appear more frequently in the literature, they also appear more frequently in this collection. Articles abstracted include only information on the basic properties that are of interest to the refractories investigator. References to crystal lattices and related topics are generally excluded from this publication. The temperature 1,500° C. has been set arbitrarily as the lower limit for reported data on thermal properties. However, because of the scarcity of information, some reports are included in which data are limited to those obtained at lower temperatures. Many of the articles abstracted include lists of references that will be of additional assistance in pursuing specific lines of investigation.

Jan 1, 1962

In March 1990, Heritage Mining conducted a 2000 line km high resolution aeromagnetic survey of all its prospects in the Coromandel Peninsula. One of the areas covered was the Onemana Peninsula, situated about 5 km north of Whangamata. Details of location and geology are given by Robson and Stevens (this volume).   The detailed helicopter-borne magnetic and radiometric survey over the Onemana area consisted of 163 line kmÆs of flying, and was carried out in order to assist in the definition of hydrothermal alteration and pre- or post- mineralisation structures. The line spacing chosen was 100 m, flown east-west, with a mean sensor terrain clearance of 80 m. Tie lines were flown north-south every kilometre for levelling purposes. The sensor was a Geoinstruments G-813 proton precession magnetometer in a towed bird, with data recorded using a Geoinstruments G-2000 acquisition system.   The Onemana alteration system is at the northern end of a major north-north east trending structural corridor defined by regional aeromagnetic surveys performed by AMOCO in 1980 (Rabone, 1991). T his structure hosts a number of other extinct hydrothermal systems including Karangahake and Golden Cross. In the Onemana contour plot the predominant north-northeast structures form the boundaries of a large area of subdued magnetism in the southern part of the surveyed area that is caused by intense hydrothermal alteration. This area is about 3.5 km long by 1 km or more wide and contains outcropping sinters and hydrothermal eruption breccias, as described in Robson and Stevens. A number of other structures transect this alteration zone, with strike directions ranging from northwest to north. A northwest feature notably truncates the zone to the south, while the northern end seems to be simi1arly bounded; however as data coverage ends at the coast, this feature is less conclusive.    Two distinctive types of strongly magnetic rock were discernible the contoured data. The strong negative magnetic anomalies the north and west are caused by fresh negatively magnetised rhyolites. This was confirmed by ground follow-up work that showed the rocks to be fresh biotite rhyolites with high magnetic susceptibilities.

Jan 1, 1991

By K. L. Murphy, G. Multamaki, P. M. Huck

"A preliminary evaluation, based on existing data, has been made of the implications of placing radium-barium sludge in tailings areas. The study was restricted to a consideration of possible increases in the quantities of radionuclides escaping to the environment through either groundwater or surf ace water, considering the types of tailings treated and the effluent treatment systems currently operating in Canada.IntroductionIn the recovery of uranium from ore deposits, the tailings produced by mine/mill complexes are conveyed to impoundment areas in slurry form. After settling, the supernatant is discharged to the environment together with runoff from precipitation on the tailings bas in. Currently, all operating uranium mines in Canada employ barium chloride treatment to control the release of dissolved radium to the aquatic environment. The dissolved radium in the tailings decant is precipitated with barium chloride, forming (Ra,Ba)SO4, and allowed to settle in ponds or lakes. In some instances, settling tanks have replaced ponds and flocculants have been added to aid settling. Because the Atomic Energy Control Board does not consider the precipitation ponds to be suitable for final disposal of these sludges, acceptable sites must be found. Options which have been suggested for sludge management include underground placement either in worked-out mine areas or in special chambers, or placement in the tailings areas. Conceptually, the latter alternative is attractive and probably would minimize sludge handling. This alternative would be subject to the AECB policy which requires that upon abandonment, radioactive releases from a tailings area must be within present regulatory limits and that treatment to meet these limits should not be required in perpetuity.No quantitative data exist concerning either the effect of physical and chemical conditions in the tailings on resolubilization of radium from precipitated sludges or the fraction of this additional radium which would be released."

Jan 1, 1982

By H. P. Greenwald

Cooperation between the Bureau of Mines of the United States Department of the Interior and the Safety in Mines Research Board of Great Britain dates from 1924. It has been intimate and has involved exchange of personnel and. equipment as well as information. Correlation of divergent results obtained in large-scale tests of the explosibility3/ of coal dusts made in the respective countries was one of the first problems to be studied. The purpose of this paper is to show to what extent such correlation has been achieved. COMPARISON OF TEST METHODS The first research accomplished Jointly by the two organizations was a comparison of large-scale methods of determining the explosibility of coal dust. Large samples of coal were exchanged and subjected to test in the Bureau's Experimental coal mine and in the Board's steel gallery, 38 inches

Jan 1, 1939

By H. P. Greenwald

Cooperation between the Bureau of Mines of the United States Department of the Interior and the Safety in Mines Research Board of Great Britain dates from 1924. It has been intimate and has involved exchange of personnel and. equipment as well as information. Correlation of divergent results obtained in large-scale tests of the explosibility3/ of coal dusts made in the respective countries was one of the first problems to be studied. The purpose of this paper is to show to what extent such correlation has been achieved. COMPARISON OF TEST METHODS The first research accomplished Jointly by the two organizations was a comparison of large-scale methods of determining the explosibility of coal dust. Large samples of coal were exchanged and subjected to test in the Bureau's Experimental coal mine and in the Board's steel gallery, 38 inches

Jan 1, 1939

Collins Radio Company, through this contract with the Bureau of Mines, has conducted a System Study of Coal Mine Communi¬cations. The program was a three phase program to establish a data base, perform communication system analysis and optimi¬zation, and prepare equipment specifications to be included in this final report. At the start of establishing a data base both a knowledge of mine communication and coal mines in general was obtained. Communication system requirements and constraints were determined along with a survey of current and potential mine communication equipment. An investigation was completed concerning theoretical LF and VLF propagation characteristics, and UHF propagation tests were conducted in a working coal mine. Different mines were contacted and on-site surveys completed with respect to coal mine communication requirements.

Jan 1, 1973

The Tenth International Conference of Directors of Safety in Mines Research was held in the United States from September 28 through October 2, 1959, at Hotel Webster Hall, Pittsburgh, Pa. The Conference was organized by the Federal Bureau of Mines. In accord with the program outlined at the Ninth Conference (1956, Heerlen, Holland), the papers submitted dealt with the following three subjects: 1. Safety of coal mine explosives 2. Explosion hazards in mines 3. Ignition and fires in mines Seventy papers were presented. There were eight technical sessions followed by an extended tour of the Bruceton facility of the Bureau of Mines on October 2. Simultaneous translation was provided in the three official languages of the Conference--English, French, and German.

Jan 1, 1962

By Blaisdell J. L, MacPherson G

The present communication records the results of a research investigation conducted in the Porcupine Gold Mines in Timmins, Onto. Soon after silicosis became a compansable disease in Ontario under the Workmen's Compensation Act in 1926, the attention of mine operators and physicians was drawn sharply to the prevalence and importance of this condition in the mining industry. A number of examining centres were established in Northern Ontario by the Workmen's Compensation Board, and the yearly X-ray examination of miners was made compulsory.Although working conditions were soon improved, the mining industry realized that they were confronted by a problem demanding basic research for its final solution. The late Sir Frederick Banting had, for a number of years, been interested in silicosis, and it was upon his suggestion that an experimental investigation was undertaken at the McIntyre-Porcupine Mines Ltd., Schumacher, Ont., in November, 1932. A preliminary report of this investigation was published in 1937 by Denny, Robson and Irwin and a further report by the same authors in 1939.Accepting the theory that silica exerts its injurious effect upon animal tissue through a slow transformation into silicic acid in the presence of body fluids; these authors assumed that if the solubility of the silicious material retained in the lung could be sufficiently reduced, the usual fibrotic response would be modified or would not occur. A search was therefore undertaken for some non-toxic compound that would fulfil this purpose. After investigating ma:qy substances, Denny and Robson discovered in 1936 that the presence of small amounts of aluminum powder almost completely inhibited the solubility of silicious material in vitro. An intensive study of the mechanism involved later showed that the reduction in solubility was due chiefly to a coating of the silica particle with a thin film of a gelatinous hydrated alumina which on drying formed the crystalline alpha aluminum monohydrate boehmite (AI203.H20). The presence of this absorbed layer on the surface of the quartz was indicated by -staining it with aurin (ammonium salt of aurin tricarboxylic acid) and proved by Germer and Storks by means of electron diffraction patterns.Inhalation experiments with animals were at once begun, using pure quartz dust with and without aluminum powder. (See original communications.) These observers showed that while typical silicosis was produced in about 5 months in the control animals receiving silica dust alone, the...

Jan 1, 1945

By Glenn S. Dobby, Glenn A. Kosick

"Column flotation circuit engineering has matured to a good level of understanding regarding testing, scale-up and design. Some of the factors important to the process of implementing columns are addressed in this paper, highlighting the following issues• operating bias and the maximum achievable solids carrying rate for a column application.• internal circulating loads of full scale and pilot plant flotation columns• short-circuiting oflarge scale columns and the impact on separation selectivity• the number of stages in a column circuit and the impact on selectivity.The paper uses several case studies, from pilot plant to full scale implementation, to illustrate these design issues.1. IntroductionTen years ago, in 1984, there were very few column flotation installations world wide and the largest columns were about I . 5 to 2 m diameter or square. During the following decade there have been in the heighbourhood of 80 column installations that have been successful and profitable, as both retrofits and green-fields plants. Now, columns as large as 3 to 4 m are not uncommon. Examples of installations with many large columns include Escondida, with ten columns each at 4 m square, and P T Freeport Indonesia, with 21 columns: nine 3 m diameter columns, four 2.4 m diameter columns and, starting up in April I 995, eight 3.6 m diameter columns.During this growth period there have also been column installations that can be considered as failures. In the majority of these cases, the reason for their failure has been an insufficient installed capacity for applications where there is a high weight recovery of solids to the froth product These include zinc cleaning, copper cleaning and iron ore flotation (silica flotation from a feed that is 15 to 30 %Si02) An application with high weight recovery to the froth product makes column scale-up and circuit design more complicated. This is particularly so if a high degree of selectivity is also required while attaining a high weight recovery, which can happen with iron ore flotation in columns."

Jan 1, 1995

By I. Gombköto, G. Földing, G. Mucsi, B. Csoke, J. Faitli, B. Kovács

This paper summarizes the main achievements of our previous project entitled "Development of a technological system producing quality guaranteed fly-ash based binder". Furthermore, this study deals with the laboratory experience of lignite fly ash utilization for two different goals. On the one hand the fly ash was tested as a binder; on the other hand it was investigated as an underground mine backfill material. Considering the first goal, the utilization of a mixture of mechanically activated fly ash and lime for producing an independent binding composition has been assessed involving determination of relationship between the degree of activation of fly ash and the strength of the obtained concrete. The results confirmed that this hydraulic binder is suitable for construction of stabilization and capping layers or base layer. Regarding the backfilling application, this paper presents laboratory experiments, their results including settling tests, hydraulic permeability and strength measurements and dense slurry technology related results.

Jan 1, 2011