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During the extensive research which has been conducted in the Metallurgy Department of the University of Melbourne, into the properties of lead and its dilute alloys, the Brinell test has been used for the determination of hardness.The work described herein represents part of an investigation into the influence of various factors on such determinations, particularly when carried out on different qualities of "pure" lead. It is intended to publish the more theoretical and controversial aspects of this research elsewhere.MATERIALS USED AND THEIR PREPARATION FOR TESTINGThe tests to be reported have been conducted on a specially pure electrolytic lead, and several brands of commercially "pure" lead. The analyses of the samples upon which most of the work has been carried out are given in Table 1.Note: Oxygen was not determined, but from the work of H. W. Worner, in the Rosenhain Memorial Laboratory, it appears probable that it was approximately 0-0003% in all samples.

Jan 1, 1940

By R. W. Brigstocke

History The birth of the mining industry of Canada took place about 1670. According to Salone (Salone E., La Colonisation de la Nouvelle France, page 205) the first discovery of ore in the country was made by an iron-master, Monsieur de la Potardiere, near Trois Rivieres, Quebec. Under French rule some prospecting was done; but at this time no one seemed to consider the working of mines practicable. It was not until the time that Begon became Intendant, when the Marquis of Vaudreuil was Governor, that mining was attempted. Begon was a patron of industrial arts and did his best to promote home manufactures. The mining industry was developed under his regime and discoveries of copper and lead ores were made in 1730. About this time the St. Maurice Forges were erected to treat bog-iron ore, and they were in operation for many years. Prior to 1747, iron pans to the value of £21,000 were manufactured, together with bar-iron and plough-shares. About 1769, that is, ten years after the conquest by Wolfe, stoves and other articles, and, later, potash kettles, appeared. What is still more interesting to us-or was, at least, to General Wolfe-is that cannon balls made at the St. Maurice Forges delayed his operations. A map dated 1744, a copy of which appears in the report of the Ontario Bureau of Mines for 1913 (Vol. XIX), indicates the extensiveness of the wanderings of the French and also shows the location of the lead mine on the east shore of Lake Timiskaming. Bog-iron ore was turned into metal, with charcoal for fuel, at Norman-dale, Norfolk county, Ontario, in 1813, and at Clementsport, Nova Scotia, in 1825. In a volume published in 1672, reference is made to the occurrence of coal on the Atlantic seaboard, and in 1677 Monsieur Duchesneau, the Intendant, levied a royalty of twenty sous per ton on all coal taken from Cape Breton.

Jan 1, 1932

By Thomas M. Barczak

This US. Bureau of Mines report examines the roof and floor contact pressure provided by the interaction of a shield with the surrounding strata. Controlled forces were applied to an 800-ton two-leg shield in the Bureau's mine roof simulator; the distribution of forces acting on the canopy and base of the shield were measured with 24 hydraulic pressure cells. Several influential factors that affect the load distribution were investigated: (1) the magnitude of loading (leg pressure); (2) the profile of the canopy, principally the upward-sloping tip; (3) the base-lifting device; (4) horizontal load acting on the shield; and (5) compliancy of the immediate roof and floor. It was concluded that the shield does not develop full canopy or base contact without deformation of the strata. Maximum contact pressures are developed at the rear of the canopy and on the toes of the base. Less than 10 pct of the available shield capacity is developed at the canopy tip despite the design intention to ensure tip contact. Horizontal loading reduced the toe pressure acting on the base by as much as 75 pct. The base-lifting device exaggerated the inherently high toe loading, increasing the contact pressure by more than 200 pct.

Jan 1, 2010

By J. Mikhael Erekson, Connie Campbell Brashear, Brent Meins

Christmas morning 2020, an IED in an RV was detonated along an evacuated section of downtown Nashville, Tennessee. The blast damaged over 40 buildings, including AT&T’s Main Central Office and caused internet and cell outages across 1,200 zip codes for three days including the airport and EMS services. Published investigations by the ATF and FBI were inconclusive in determining the explosive composition and size. Video captured a large fireball that may indicate a fuel-air-mixture explosion which would create lower peak pressures than high explosives, but longer pressure duration and significant impulsive loading. Blast pressures were amplified by reflections in the urban environment bordered by the 8-story AT&T building and a row of multi-story historic buildings. Some structures had little damage as they were shielded from the blast pressure by closer buildings, and seemingly far-field structures contained damage from the pressure wave after multiple reflections and propagation through porous parking garages. Damage to the reinforced concrete frame AT&T building included snapped masonry ties, cracking and spall to the closest column, and vertical displacement of the elevator, even with the brakes applied. The historic structures directly across the street from the blast partially collapsed. Initial damage included complete failures of unreinforced masonry façades, broken timber beams, and uplifted roofs. Secondary, progressive collapse took place over months as the brick walls and weakened historic mortar could not resist typical wind and environment loads. One of the close historic structures was renovated in the 1990’s and structural retrofits to comply with building codes were required. The addition of steel columns and façade tie-ins improved survivability and it remained standing with a high percentage of the front brick intact. Generally, the observed blast damage was related to a structural component’s mass and flexibility. Internal timber framing was unscathed, but many steel studs required replacement. Glazing damage was observed several blocks away and many roof membranes were punctured by falling debris. Secondary damage from broken sprinkler lines and loss of environmental control often led to more costly repairs than the initial blast pressure damage. The proliferation of bomb-making knowledge leads to hundreds of bombings each year in the US. Building risk considerations should include explosive threats along with other hazards. ASCE structural standards and design manuals have been published to address these risks and may be useful guides for building construction.

Feb 6, 2023

By Roozbeh Afzali

Designing an appropriate tunnel blasting pattern reduces the cost of rock breakage and subsequent operations such as loading, haulage and support of tunnels. For that reason, we developed a software that designs tunnel blasting patterns. Using this software, three different tunnel blast design models based on parallel hole cut, namely, Swedish, Konya and Energy Balance, were investigated and compared for a virtual tunnel. Accordingly, blasting patterns were designed, for different cross sections. The trend of parameters such as specific charge and specific drilling as functions of tunnel cross-section was determined for each model. Our results show that, in general, The Swedish model gives lower specific charge and specific drilling compared to other models.

Jan 1, 2008

By J. S. Hansen

To advance technology that can conserve critical materials, the Bureau of Mines investigated a cast-on hard-surfacing that wear resistance and confines alloy additions to wear-prone surfaces. Wear-resistant material in form is on a polystyrene , the is embedded in a mold of unbonded s and the wear-resistant material is transferred to a cas surface at the time of For low-stress abrasion, derived from high-carbon ferro-chrome had higher wear resistance than did commercially available weld-hard. The microstructure of the was typi-white iron carbides. Free carbon added to the ferrochrome powder produced more M7C3 carbides than did material contained in surfacings made from ferrochrome alone, and improved the wear resistance. Several white iron powders with greatly reduced chromium contents also white iron contain-M7C3 carbides. One derived from white iron powder had wear resistance to that of weld-deposited hard facings. Among the parameters investigated, surfacing thickness was found to have a or influence on diffusion of elements out of the , microstructure, and wear resistance. The results of field tests on bucket-wheel excavator teeth and plowshares with cast-on hard surfacing are given.

Jan 1, 1985

By James C. Barker

The analytical variability encountered when sampling for platinum-group metals (PGM) was statistically evaluated during a 1983 study by the Bureau of Mines and the University of Alaska. Sampling procedures were designed to systematically incorporate commonly used reconnaissance exploration techniques under actual field conditions. Analytical variability was evaluated at each procedural step. Analytical data from each sample from a single deposit grouped relatively well around the calculated mean for that deposit. Standard deviations did not exceed 43 pct of the mean for any of the deposits; more commonly, the deviation was about 25 pct. Statistical treatment of the data by analysis of variance indicated the most important source of error is selection of the sample site. Two or more replicate samples appear necessary to adequately quantify the PGM content. Secondly, significant variation occurs during preparation of a pulverized split for fire assay. The optimum sample size was in the 11-lb range; larger samples did not appreciably reduce variability. Smaller samples generally indicated a higher degree of variability. Evaluation of the sample method suggested the common grab sample, if carefully taken, is a useful indicator of the general range of PGM concentration but potentially includes a considerable margin of error.

Jan 1, 1985

By B. P. Watson

The first crush pillars on the Bushveld platinum mines were introduced at Union Section in 1978. Before the introduction of crush pillars, serious problems were experienced when stoping advanced to a point 30 m to 40 m on both sides of the centre gully. At least three to four stopes were collapsing per month. The introduction of the pillars stopped the stope collapses in the mining area where they were introduced. The residual stresses of these pillars were never measured; however, the successful elimination of the ?back-break? problem suggests that the original pillars had a residual strength of at least 8 MPa. Apart from back analyses, very little work has been done to determine the residual strength of crush pillars and only very recently have any measurements been made. The lack of knowledge in this field has resulted in pillars being designed based on experience. Concerns about stope collapses, similar to the Coalbrook disaster, have led to larger pillars being cut in more recent times. If such pillars were cut in brittle quartzites they would always fail violently but the ductile nature of the Merensky Reef generally allows large pillars to fail without bursting. Occasionally, however, one would burst in a working area. Increased incidence of bursting has been reported on some mines at deeper levels but most of these bursts occur in the back areas. Nevertheless, the incidence of bursting increases the risk of falls of ground in already dangerous areas, and the larger pillars decrease the extraction ratio. This paper describes the evaluation of stress measurements conducted in two boreholes over a crush pillar with dimensions 2.5 m x4.0 m, and a height of 1.2 m. Boussinesq equations for vertical and shear stress were used to analyse the original measurements and provide a stress profile across the pillar as well as the residual strength of the pillar. The results showed an unexpectedly high peak stress of 280 MPa at the centre of the pillar and a residual strength of 48 MPa. The reason for the high residual strength is suspected to be the result of the stiff environment under which the pillar failed and the small height of the siding on the up-dip edge of the pillar. More measurements should be conducted on several mines to establish a range of residual strengths for narrow crush pillars.

Jan 1, 2008

By William H. Pomroy

The potential for large-scale fires in underground fuel storage and fuel transfer areas prompted the Bureau of Mines to study fire hazards in these areas and devise improved fire safety technology for use in these areas. This report describes the Bureau's research to characterize and quantify fire hazards in fuel storage and fuel transfer areas, develop guidelines for safe and efficient fueling system design, prepare specifications for automatic fire sensing and suppression systems for these areas, test prototype systems in the laboratory and in underground mines, and perform cost-effectiveness evaluations of the devised technology.

Jan 1, 1985

By Kefton H. Teague

This paper deals with the practical application of the Dutch State Mines cyclone separator for fine-coal cleaning. The more important operating variables are discussed, and results of a number of continuous-scale tests on various fine coals with a 6-in. cyclone separator are given. Descriptions of the Cyanamid Pilot Plant and the 50 tph Cyclone Separator Plant at the Emma Washery in Holland are included.

Jan 1, 1950

By A Buckley

Many policy issues facing the mining industry and affected communities are at a level of complexity that they can be called ‘wicked’ problems. The term ‘wicked’ in this context is used, not in the sense of iniquity, but rather as social and economic issues highly resistant to resolution. For the resource extraction sector and affected communities there are an array of challenges embedded in the industry’s production and profit paradigm, the remoteness of mineral reserves and affected communities’ expectations of economic benefit and a positive legacy. The mining industry as a whole is dominated by economic, political, legislative and market structures that influence and constrain interactions between mine operations and local communities. For communities, with particular reference to regional Western Australia, intractable problems include the uncertainty of, yet increasing dependence on, a mining economy. Questionable outcomes for local communities include the limited realisation of local employment and business development benefits, and low overall outcomes or low multiplier effects. ‘Wicked’ problems, according to the literature, are best addressed via collaboration. In the mid-west region of WA, with mining and infrastructure construction underway, alliances have formed between mining companies, the major port and rail infrastructure project (Oakajee Port and Rail) and regional and local governance stakeholders. The major impetus for these affiliations is to expedite planning and associated infrastructure development taking into account the lessons from other mineral-led regions. What has resulted is an array of innovative approaches to stubborn problems including planning well in advance of full-scale mining; regionally coordinated procurement; ‘mine ready’ local businesses; and strategic investments in social infrastructure; including community trust funds paid in advance of project delivery. This paper examines these innovative approaches/alliances and assesses their effectiveness in addressing long standing mining/community dilemmas.

Nov 22, 2011

By Marcello M. Veiga

Informal gold mining operations in the Amazon emit about 100 tonnes of mercury annually because of poor amalgamation practice. Lack of information and the complexity of mercury transformations hinder effective action to prevent such pollution and/or monitor its extent. In the past, mathematical equations have been formulated to deal with the correlation of natural variables and mercury in biota but often, the error range is too great to provide useful models. Projection of physico-chemical variations in an environment subjected to mercury emissions onto the extent of bioaccumulation is fraught with many uncertainties and unknowns such as internal correlations between variables and the site-specific nature of biota contamination. Often assumptions about closed systems are invalid when applied to natural environments. This work presents a heuristic approach to this problem in which amalgamation methods and natural variables are dealt with using an IF-THEN rule-based system that concludes about levels of emission and risk of bioaccumulation. The system is able to handle uncertain or vague data and yet still provide useful output. Belief in mercury oxidation or dangerous conditions are examined using Fuzzy Logic techniques and Inference Equations. These belief levels are derived from thermodynamic equilibrium data together with field observations of natural variables. This procedure can reduce the need for sophisticated analytical equipment and can provide information and diagnosis to non-technical people.

Jan 1, 1994

By John D. Bardill

A cooperative project between the Bureau of Mines, Department of the Interior, and the Montana School of Mines, investigating results of hydraulic systems for transporting sand slurries for emplacement, was begun in August 1955. In such circumstances, the Bureau provides funds for a fellowship leading to a Master of Science degree as well as available instruments, tools, supplies and equipment. The School provides the ore-beneficiating laboratory with its equipment for use as a pilot plant. The success of a hydraulic backfilling method employing mill tailings depends largely upon the physical characteristics of the tailings. One of these characteristics is size distribution, especially in the finer size ranges. When being emplaced underground, almost impervious layers of slimes separate from some types of mill tailings containing a high percentage of slimes and settle on the top of the sand fill. These coatings may be so dense that the water in the slurry cannot percolate through them for proper drainage. Successive layers of fill in a stope, each with an impervious coating on top, sometimes build up a hydrostatic head, creating pressure on the bulkheads. This may cause breaks in the lining material, inducing sand runs and flooding the level and sumps below. Deleterious slimes flocculated and disseminated throughout the sands should help prevent the formation of impervious slime layers, increasing percolation and settling rates.

Jan 1, 1960

Abbey, Robert Graham, District Mgr., The W. W. Sly Mfg. Co., 50 Church St., New York, N. Y. '21 Abbott, A. N Ave. Morelos 84, Cuernavaca, Morelos, Mexico '23 Abbott, Argyle Campbell, Geol 42 Everett St., Arlington, Mass. '29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg., Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Consolidation Coal Co., Watson Bldg., Fairmont, W. Va. '15 Abeel, George H., Jr., Cons. Min. Engr 1281/2 S. Canon Dr., Beverly Hills, Cal. '18 Abel, Raymond L., Asst. Prof., Dept. of Pet. Refin., Univ. of Pittsburgh. .Pittsburgh, Pa. '28 Abel, Walter D., Cons. Engr 650 S. Grand Ave., Los Angeles, Cal. '82 Abele, Louis T., Min. & Met. Engr., Supt., Texas Hill Mine Coulterville, Cal. '31 Abell, Leo M. Millicent, S. Australia '31 Abernathy, George Elmer, Prof. of Geol. & Min., Kansas State Teachers College, Pittsburg, Kan. '20 Aborn, Robert H., Research Lab., U. S. Steel Corp. Lincoln Highway, Kearny, N. J. '19 Abozeid, Mahmood, Dept. of Mines & Quarries Cairo, Egypt '26

Jan 1, 1932

By T. C. Moore

This report describes the feasibility test of an electromagnetic method for locating boreholes, with or without casing, that have been drilled in conjunction with mining operations but whose location with respect to the tunnel is not precisely known. The first tests were conducted with the cooperation of the Kerr-McGee Corporation, Church Rock Mining Operations, New Mexico, in September 1977. These tests demonstrated that accuracies of better than ±5% of range and ±1° of bearing can be achieved with a simple system and setups. Subsequent tests, in January 1978, on a horizontally drilled pipe line river crossing application, by Titan Contractors of Sacramento, California, demonstrated that accuracies of better than one-half percent of range and a few tenths of one degree of bearing can be achieved by using refined techniques. The demonstration tests were done at ranges on the order of 100 to 200 feet but the method is capable of working at much greater distances.

Jan 1, 1978

By H. O. Hofman

WHEN dry chlorine gas is made to act in the cold upon finely¬divided gold,' it converts the latter with evolution of heat into auro-auric chloride, Au2CI4, a hard, dark-red, hygroscopic salt. Moisture splits this salt into aurous and aerie chloride, Au2C14 = AuCI + AuCI3; treatment with water converts it into auric chloride and gold, 3 Au2CI4 = 4 AuC13 + Au,. Aurous chloride, when stirred with water, undergoes a similar decomposition, 3 AuCI = AuCI3 + Au,. These decompositions of auro-auric chloride and of aurous chloride furnish the explanation for the practice of moistening an ore before it is treated by the Plattner chlorination-process; practical experience having shown that gaseous chlorine gave an unsatisfactory extraction with dry ore. According to Rose,' fine gold is acted upon more slowly by chlorine than gold containing some base metal, e.g., copper. He also states that small quantities of silver increase the rate of solution, but adds that the coating of silver chloride formed checks, and finally stops, further action, if the percentage of silver be increased beyond a certain undetermined amount. Bromine' acts upon finely-divided gold in a manner similar to chlorine; the auro-auric bromide, Au2Br4, however, is not hygroscopic. Upon treatment with water it is decomposed as is the corresponding chlorine salt. It is generally believed that bromine does not act as energetically upon gold as does chlorine. This seems to be borne out by the results in the leach-

Mar 1, 1905

By Norman G. Foster

The mass spectra of four tertiary butyl substituted thiophenes are reported. A comparison and contrast with earlier structure correlations made by API-RP48 mass spectroscopists is presented. The fragmentation routes of these types of molecules are discussed and explained in terms of existing theories in mass spectrometry. Low ionization voltage data are presented to support the mechanistic picture developed. Structures are inferred about some of the ions, and these are correlated with existing theories. Metastable peaks in the spectra are used to support the fragmentation paths. The presence of doubly charged ions in the spectra is noted and the possible implications toward mechanisms discussed. The general picture of simple, small fragments leaving the ion moiety upon further fragmentation is developed in detail. Some suggestions are presented for further work utilizing isotopically labeled molecules to establish firmly the general picture of fragmentations of the alkylthiophenes.

Jan 1, 1966

By M. Hakala

A computer program was developed to simulate transient strains and stresses during an overcoring in the situ stress measurement. The solution is based on superpositioning of elastic stresses. The measured strains can be compared with the calculated ones to check if the measured transient behaviour is accordant with the interpreted in situ state of stress. If not, the in situ state of stress can be calculated based on any transient or final strain values. The transient stresses can be compared with the strength envelope of intact rock and thereby estimate the core damage potential. Technically, the developed code fulfilled all the objectives, and the numerical error was found to be less than 5%. The basic idea can be applied also for different overcoring probes with minor modifications and recalculation of stress tensors. The analysed case studies showed clearly the advance of having an objective and practical quality control method to study the reliability of the in situ stress measurement data. The study was set up and funded by the nuclear waste management companies Posiva Oy ( Finland ) and Svensk Kärnbränslehantering AB ( Sweden ). Un programme informatique a été développé pour simuler des tensions et des contraintes passagères pendant la mesure in situ de contrainte de surcarottage. La solution se fonde sur une superposition de contraintes élastiques. Les contraintes mesurées peuvent être comparées avec celles calculées pour vérifier si le comportement passager mesuré correspond à l'état de contrainte in situ interprété. Sinon, l'état de contrainte in situ peut être calculé à partir de n'importe quelle valeur de contrainte passagère ou finale. Les contraintes passagères peuvent être comparées avec l'enveloppe de force de roche intacte et ainsi il est possible d'évaluer le potentiel de dégâts au noyau. Techniquement le code développé a rempli tous les objectifs, et le taux d'erreur s'est révélé être inférieur à 5 %. L'idée de base peut être appliquée aussi pour différentes expériences de surcarottage avec des modifications mineures et le recalcul de tenseurs de contrainte. Les études de cas analysées ont montré clairement l'avantage d'avoir une méthode de contrôle de qualité objective et pratique pour étudier la fiabilité de données de mesure de contrainte in situ. L'étude a été fondée et financée par les sociétés de gestion de déchets nucléaires Posiva Oy (Finlande) et Svensk Kärnbränslehantering AB (Suède). Es wurde ein Computerprogramm entwickelt, um Transient-Beanspruchungen und Spannungen während eines Überentkernens in situ-Spannung-Messung zu simulieren. Die Lösung beruht auf Superpositionierung von elastischen Spannungen. Die gemessenen Beanspruchungen können mit den berechneten Daten verglichen werden, um nachzuprüfen, ob das abgemessene Transient-Verhalten mit dem interpretierten in situ-Zustand der Spannung übereinstimmt. Wenn nicht, kann der situ-Zustand der Spannung auf irgendwelchen Transient- oder endgültigen Beanspruchungswerten berechnet werden. Die Transiet-Spannungen können mit dem Stärke-Umschlag des intakten Felsens verglichen werden und dadurch ein Kernbeschädigungspotential kalkulieren. Technisch erkannte der entwickelte Code alle Ziele und hat gefunden, dass die numerische Fehler weniger als 5 % waren. Grundsätzlich können auch verschiedene Überentkernen-Untersuchungen mit kleineren Modifizierungen und Wiederberechnung des Spannung-Tensors angewandt werden. Die analysierten Fallstudien zeigten deutlich den Fortschritt, objektive und praktische Qualitätskontrollmethode zu haben, die Zuverlässigkeit in Situ-Spannung-Messung-Daten zu studieren. Die Studie wurde aufgestellt und durch Atommüll-Management-Firmen Posiva Oy (Finnland) und Svensk Kärnbränslehantering AB (Schweden) finanziert.

Jan 1, 2003

By D. H. NETLAND

DURING the year 1907 an investigation of the Clinton formation in New York has been carried out under the direction of the State Geologist, and a full account of the results has been prepared for publication.1 The more important economic features of the report are summarized in the present paper. Previous knowledge of this, the type, section of the Clinton has been contributed mostly by Hall and Vanuxem in their reports for the Natural History Survey of New York, which were issued in their final form in 1842-43. Brief accounts of the ore-occurrences have been given by B. T. Putnam,2 J. C. Smock,3 A. H. Chester,4 and E. C. Eckel.5 Prof. C. H. Smyth, Jr.,6has discussed the origin of the Clinton ores in two papers, which, so far as the local occurrences are concerned, have removed all doubt that may have existed on that subject. Distribution of the Clinton Formation. The Clinton strata in New York State are restricted to a single belt, Which extends from the eastern central part to the Niagara river, which it crosses, and thence continues for some distance into the province of Ontario. The New York

Mar 1, 1909

By Matheus Teixeira Fraga

É comum o uso de modelos matemáticos no intuito de prever a qualidade do coque, sendo a maioria dos modelos atualmente disponíveis baseada nas propriedades dos carvões. Para este trabalho foram feitas misturas binárias e ternárias de carvões com variados teores de matéria volátil, a fim de se produzir coque em escala laboratorial. A reatividade ao CO2 em termobalança e resistência mecânica em tambores foi avaliada. Dois modelos para previsão de indicadores de qualidade do coque foram avaliados, o modelo aditivo e o modelo de interação. A partir da metodologia desenvolvida em laboratório foi possível produzir, avaliar e comparar coques feitos a partir de diferentes carvões e misturas. O modelo aditivo mostrou uma boa capacidade de prever a reatividade dos coques. No entanto, para os índices derivados dos testes de tambores os valores calculados mostram uma diferença importante em relação aos experimentais, indicando interação dos carvões no processo de carbonização. Nos resultados do modelo de interações, os valores calculados para reatividade e resistência mecânica, se comparados com os resultados do modelo aditivo, mostraram uma melhora na capacidade de previsão da qualidade do coque. O modelo de interações se apresenta como uma ferramenta interessante na seleção e mistura de carvões.

Aug 17, 2017