Search Documents

By R. M. Hays

Jan 1, 1980

By Marie-France Caille, Carl Caumartin

"Audrey Resources' Mobrun Mine is located in Dufresnoy Township some 30 km to the northeast of Rouyn-Noranda. The Mobrun tine deposits consist of two major massive sulphide lenses; the newly discovered 1100 lens located 450 m south of the Main zone, and one ntellite lens, the 850-870-930 complex.The 1100 lens is hosted in a large pyroclastic unit bounded to the mouth by rhyolite and andesite flows and by a thick rhyolite unit to the art h. stratigraphically belon the three lenses. It consists of approximately 15 Mt of massive sulphide, of which 10.4 Mt are of economic ade. The Main lens lies comformably above thick rhyolite flows, ecciated and pyritized by the sulphide horizon, and is overlain by ttercalated ash tuffs and rhyolites which host the over-lying satellite ns. The Main lens consists of 3,3 Mt of massive sulphide, of which 523 000 tgrade0.80% Cu, 2.44%Zn,30.19 g/t Ag, and2.2 g/t Au he richer satellite lens (180 000 t) is part of the same volcanic stem and resulted from a resurgence of hydrothermal activity. ructure played a role in the final geometry of the deposits but did not eatly affect the volcanogenic and stratabound nature of the lens. Total production since the start of operations in 1985 amounts to 58 000 t and is restricted to the Main lens. Production from the 100 will come onstream in 1992 as ore reserves from the Main and e satellite lenses are exhausted.RESUMELa Mine Mobrun de Ressources Audrey inc. est située dans le mton Dufresnoy, a quelque 30 km au nord-est de Rouyn-Noranda. lle comprend deux lentilles de sulfures massifs d’importance majeure ~i sont les lentilles 1100 et Principale, et une lentille satellite qui est complexe 850-870-930.La lentille 1100, la plus ancienne, est contenue dans une épaisse 1ite pyroclastique bordée, au sud, par des coulées de rhyolite et d’andésites, au nord, par une épaisse unité rhyolitique. Cette lentille contient environ 15 Mt de sulfures massifs dont 10,4 Mt à teneur économique. La lentille Principale repose sur d’épaisses coulées rhyolitiques brechifiees et pyritisees à proximité de l’horizon de sulfures; elle est recouverte de tufs a cendres et de rhyolites interlitees qui contiennent la lentille satellite. La lentille Principale est constitute de 3,3 M t de sulfures massifs dont 1 523 000 t sont économiques avec une teneur moyenne de 0,80% Cu, 2,44% Zn, 30,19 g/t Ag, et 2,2 glt Au. Faisant partie de ce second épisode volcanique, la riche lentille satellite (180 000 t) temoigne d’une recrudescence de l’activité hydrothermale. La structure joue un rôle important dans la géométrie finale des dépôts mais ellen' affecte pas, de fa~on significative, la nature volcan génique des lentilles. Depuis le début des opérations, en 1985, la production totale est d’environ 568 000 t, provenant essentiellement de la lentille Principale. La mise en production de la lentille 1100 est prévue pour 1992, alors que les réserves des lentilles Principale et Satellite seront probablement épuisés."

Jan 1, 1990

By Max L. Glenn

As part of its goal to minimize requirements for mineral commodities through conservation and substitution, the Bureau of Mines conducted research to develop molybdenum as a potential substitute for superalloys containing the strategic and critical materials, nickel, chromium, and cobalt. Since molybdenum requires protection from oxidation at high temperatures, several complex oxides of the spinel and perovskite structure were investigated to determine which possessed the greatest potential for use as oxidation-barrier coatings. Two spinels (MgCr204 and MgA1204) and five perovskites (BaHfO3, YCrO3, NdCrO3, BaZrO3, and LaCrO3) were selected for testing. Various high-temperature prop¬erties that are important for oxidation-resistant coatings were examined, including diffusion rates of oxygen and molybdenum, recession (vaporization) rates, hardness, erosion resistance, sinterability, reactivity with molybdenum, and ease of application. From the evaluation of high-temperature properties, two spinels (MgCr204 and MgA1204) stand above the other oxides as possible coatings for molybdenum. However, laboratory coatings of MgCr204 at 1,360° C (2,480° F) are equivalent or inferior to currently available MoSi2 coatings; laboratory coatings of MgA1204 may be comparable under limited conditions to currently available MoSi2 coatings at the same temperature.

Jan 1, 1979

By J. Dong

"A “green” collector project has been initiated at Vale Base Metals Technology Development to replace xanthate. Bench and miniplant testwork showed comparable metallurgical results between xanthate and DTC (sodium dibutyl dithiocarbamate), a “greener” collector. During the first DTC plant trial, a strong interaction between the process water and DTC negatively impacted the metallurgy. The subsequent investigation showed that the quality of process water including suspended solids and dissolved metal ions had a significant impact on the performance with DTC, while less so with PAX. This paper explains these differences using UV spectrophotometry and batch flotation tests. INTRODUCTIONVale Base Metals is dedicated to sustainable mining and mineral processing. One of the key activities is to find a “greener” collector to replace xanthate (PAX: potassium amyl xanthate), which decomposes during storage and flotation causing CS2 emissions in the work place. As the most promising candidate, DTC (sodium dibutyl dithiocarbamate) was evaluated in the lab and miniplant (Dong & Xu, 2011). Consequently, a plant trial was conducted in the winter of 2010. However, the results were not as good as expected. The subsequent investigation showed that the quality of process water played a significant role in the metallurgical performance with DTC but less so with xanthate.From test work in 1996 and 1997, a series of batch tests were performed at Clarabelle Mill to investigate the winter/summer metallurgical shift with xanthate. As shown in Figure 1, the winter metallurgy was considerably worse than the summer metallurgy (Xu & Wilson, 2000). At 80% pentlandite recovery, the concentrate (Cu+Ni) grade was 21% in the winter and 26% in the summer. At 23% (Cu+Ni) concentrate grade, pentlandite recovery was 85% in the summer and 70% in the winter. In the summer, the process water is much cleaner, with very low concentrations of dissolved metals ions and suspended solids; while in the winter, the water is yellow and cloudy, with much higher suspended solids. Based on these results, it was concluded that the process water in winter has a detrimental impact on metallurgy."

Jan 1, 2012

By Fernando Dellacqua Cristo

Durante o processo de desfosforação, as principais fases sólidas formadas na escória são o silicato dicálcico (2CaO.SiO2) e tricálcio (3CaO.SiO2), o fosfato tricálcico (3CaO.P2O5), e o 3CaOSiO2.3CaOP2O5 formado pela oxidação do fósforo em solução sólida com o silicato tricálcio. O objetivo deste trabalho é estudar a formação destes compostos e avaliar a influência das fases sólidas e líquidas formadas na eficiência da desfosforação. Foram analisadas diferentes composições de escórias industriais com diferentes teores de CaO e FeO. As fases presentes na escória e a sua viscosidade foram determinadas pela termodinâmica computacional utilizando o software FactSage (usando os bancos de dados GTOXID e FTOXID) e os resultados destas análises foram relacionados com a eficiência de desfosforação. A eficiência da desfosforação também foi relacionada com os diferentes modelos de relação de partição do fósforo (Lp) disponíveis na literatura.

Aug 16, 2017

By AIME AIME

MODERN metallurgy is an art and a science. The art is process metallurgy-extracting metals from their ores, refining them, and alloying them with one another and with certain nonmetals to produce thereby a variety of metallic materials which, owing to a wide range of useful properties, are for many purposes more valuable to man than the individual metals themselves; process metallurgy also includes shaping or otherwise treating metals and alloys to form objects useful to a complex industrial world. The science is physical metallurgy-organized knowledge of the constitution and internal structure of metals and alloys, of the relation of their composition and structure to properties, and of the laws, theories, and hypotheses that purport to explain this relation.

Jan 1, 1942

By Thomas E. Weyand

Prior to 1975, lead-based paints were commonly used in protecting steel structures. Because of the toxic effects of lead on human health and the environment, their use has been significantly reduced. However, problems with these paints persist when they are removed during normal maintenance by pneumatic blasting with mineral abrasives. Technologies are developed to contain the spent abrasive and paint during blasting operations. This paper reports on A study to identify beneficial reuses for the spent blasting material. Nine samples were gathered from different projects within Pennsylvania. The samples were thoroughly characterized with regard to composition, morphology, and EP and TCLP leach test performance. Potential reuse applications will be reviewed with regard to technical adequacy, economics, and environmental constraints.

Jan 1, 1992

By William H. Pomroy

Spontaneous combustion fires involving high-sulfide-content ores are a relatively infrequent yet serious safety hazard in mining. They are also the cause of lengthy mine shutdowns because they typically occur in areas of a mine where abundant fuel material is present but which are inaccessible for fire fighting. This Bureau of Mines report describes research to design, fabricate, and test in the laboratory and field a system that warns of spontaneous combustion fires in metal mines. Overall performance of the detection system was found to be satisfactory, in that the system was capable of reliably detecting low levels of combustion products believed to indicate the preflaming stage of spontaneous combustion in metal mines. Installation of similar systems in mines with a high risk of spontaneous combustion is recommended. Principal operating problems and recommended corrective actions are also discussed.

Jan 1, 1987

By E. H. W. Hornbrook, P. W. B. Friske

Paper presented at the 28th International Geological Congress, Washington DC, July 1989 (International geochemical mapping sessions). The objective of the programme is to establish and maintain a nationally consistent geochemical drainage database. Towards this end systematic surveys have been conducted since 1973. To date more than 200 surveys have been completed to the required standards, representing 180 000 sites and covering about 2 100 000 km2 throughout Canada

Jun 13, 1905

By J. F. Brand, J. C. van Dyk, F. B. Waanders

"Syngas from Africary’s Theunissen underground coal gasification (UCG) project will be used for power production and synthesis of liquid fuels and commodity chemicals. However, some of the coal components, especially condensable water, oils, tars, inorganic trace elements, and a small fraction of fly ash and particulate matter, make their way to the surface via the production well and can cause adverse impacts on downstream processes. Africary’s standard design incorporates a cold gas clean-up system that relies on relatively mature techniques based on highly effective wet scrubbers and acid gas removal (AGR) systems such as Rectisol®, but with the downside of low energy efficiency and waste water generation. In this paper, novel technologies for removing contaminants and species separation from the hot (T > 300°C) raw syngas are compared. Comparisons are made between supersonic gas separation (SGS), Ranque–Hilsch vortex tube (RHVT), vortex gradient separation (VGS), and inertia vacuum filtering (IVF), and a vortex-based gas separation concept is proposed for UCG applications. IntroductionImpurities in gasification feedstock (coal, biomass, waste, etc.), especially sulphur, nitrogen, chlorine, and inorganic mineral matter, often end up in the syngas and can cause adverse impacts on downstream processes. Africary’s standard design incorporates a cold gas clean-up system that relies on relatively mature techniques based on highly effective wet scrubbers and acid gas removal (AGR) systems such as RectisolR, SelexolR or aMDEAR; but with the downside of low energy efficiency and waste water generation.Hot (T > 300°C) gas clean-up technologies are attractive because they avoid cooling and reheating of the syngas stream. Some available warm gas cleaning technologies include traditional particulate removal devices such as cyclones, candle filters, membranes, and molecular sieves. The warm gas desulphurization process technology developed by RTI LLC (2018) requires hot syngas to remove sulphur and has become commercially ready. Many other hot gas cleanup systems are still under development, given the technical difficulties caused by extreme environmental and operating conditions."

Jan 1, 2018

By Roy E. Peterson

The Bureau of Mines has been developing and evaluating methods for beneficiating the large deposits of nonmagnetic (oxidized) taconite located on the western Mesabi Range. In this segment of the research, a sample representing about 0.5 billion tons of nonmagnetic taconite from near Grand Rapids, Minn., was beneficiated using a reduction roasting, magnetic separation, flotation process. The sample contained 32.1 pct iron and 49.1 pct silica. Tests were conducted both on a bench scale and with a 1,000-lb/h pilot plant. In the bench-scale research a con-centrate containing 69.0 pct iron and 4.5 pct silica was produced with an iron recovery of 82.1 pct. In the pilot plant, reduction roasting was conducted in a 35-ft kiln using lignite as the reductant and major source of fuel. Dust from the kiln exhaust was pelletized and recycled to the kiln. The roasted taconite was beneficiated by magnetic sep-aration and flotation to produce a product containing 67.9 pct iron, 5.5 pct silica, and 69.7 pct of the iron in the kiln feed. The cyclone separation in the grinding circuit was sharpened by demagnetizing the cyclone feed in a 400-Hz, 1,000-Oe magnetic field.

Jan 1, 1983

By Martin Bergeron

Producteur d?or de taille intermédiaire Mines Aurizon Ltée Bureau-chef àVancouverMine et projets localisés au Québec2

May 1, 2011

By R. Hazael, R. Alford, R. Critchley

The ability to compare explosives is fundamental. Numerous methods are used and while simple conversion factors are often used, the use of TNT Equivalency (TNTe) is not a simple subject as explosives exhibit very different equivalencies depending on whether the pressure or impulse are being considered as well as other conditions. The scaled distance has been found to have a significant effect on the TNTe but due to the difficulty of taking measurements at very close ranges, no TNTe have been quoted for charges in direct contact (Z=0). This paper describes the use of a ballistic pendulum to measure the impulse from contact charges and presents some surprising results that require a two-stage propulsion, as originally described by Backofen, to be explained.

Jan 1, 2024

The influence of fuel additives on automobile exhaust emissions was studied using engines currently found in the U.S. vehicle population. The fuel additives used in the experiment were four multifunctional additives and one lead antiknock additive. Experimental work was done to determine both the direct effect of the additive per se on exhaust emissions and the influence of Long-term additive effects on emissions with mileage accumulation. Results showed no significant direct or intermediate effect on exhaust emissions for any additives tested. In subsequent experimental work concerned with the long-term or indirect effects of additives, the detergent-dispersant additives were found to have little influence on emissions when used in conjunction with high-quality oil and motor fuel. The lead (tetraethyl) antiknock additive increased exhaust hydrocarbons approximately 12 to 17 percent during a 4,000-mile accumulation period using a base fuel containing 2 ml of tetraethyl lead per gallon. An unleaded fuel was used during a similar accumulation period with no significant increase in exhaust hydrocarbons with mileage.

Jan 1, 1971

By D. G. Hattingh, A Els-Botes

"Considerable information is available on the factors influencing the iron-zinc reaction rate at 450° C of low carbon steels, in comparison there is a scarcity _of similar fundamental information of spheroidal graphite irons. This can be attributed to the more complex microstructure and ferrous alloy chemical analysis of spheroidal graphite irons. Hot-dip galvanizers have identified the complexity in controlling and predicting the thickness of the galvanized coating formed on commercial cast irons, which has serious financial implications for both the galvanizer and customer.Commercial hot-dip galvanizing has been in use for over 160 years and yet an elementary understanding of the dynamics associated with the hot-dip galvanizing of spheroidal graphite cast iron is still insufficient. To allow the. process to become a modem surface engineering technology, the fundamental aspects of the process must be thoroughly understood.When a clean iron or steel article is dipped into the molten zinc, zinc initially solidifies around the steel or iron. As heat is transferred to the article form the bath, this initial solidified zinc layer remelts and a series of iron-zinc alloy is formed by the reaction of the zinc with the surface of the article; on removal from the bath, some of the molten zinc is taken out on top of the alloy layers. At normal galvanizing temperature (450 °C), the reaction between iron and zinc is usually parabolic with time. The rate of reaction is rapid at first but then slows down and the coating thickness does not increase greatly if the article is immersed in the bath for longer times(1)."

Jan 1, 2000

By J. F. T. Agapito

Significant economic benefits can result when rock mechanics is applied within a practical framework and integrated within the other engineering functions of the mine organization. This requires management support and understanding of rock mechanics as a practical tool to help attain high standards of safety, productivity and resource recovery. For such an approach, a long-term geotechnical program is needed in most operations to build an adequate data base and to ensure that design and ground control issues are handled in a cost-effective manner. This paper presents a summary of four case studies where significant economic benefits were realized with the help of rock mechanics. Although cost savings were not computed, the economic benefits are obvious and clearly impacted the mine operations favorably.

Jan 1, 1990

By Lon Santis, Gregory M. Rumbaugh, Christopher Mark

This paper examines the relevant theory, experience, and past practices relating to development mining near gas or oil wells. It addresses setback distance for both coal and stone room-and-pillar mining. This study also involved a review of accident reports involving well interceptions and downhole well surveys. It provides technical considerations for decisions regarding safe setback distances for development mining throughout the United States. The study’s scope is limited to mining near active or inactive (i.e., non-producing, abandoned or inadequately plugged) wells with known surface locations.

Jun 25, 2024

By Juan Garcia de Blas, Allan Ribeiro de Souza

uso do método dos elementos finitos (MEF) para uma determinação mais realística da resistência estrutural de aços estruturais sob a ação do incêndio vem crescendo à medida que um número maior de países vem adotando os códigos baseados em desempenho no lugar dos tradicionais códigos prescritivos. O algoritmo MEF interpreta o comportamento termomecânico do aço através do emprego de modelos constitutivos. Os modelos constitutivos convencionais usados na engenharia de incêndio são de natureza empírica e abordam de forma dissociada os fenômenos do encruamento plástico e da fluência. Este trabalho apresenta em linhas gerais um modelo constitutivo unificado baseado fisicamente na cinética de deformação plástica resultante do deslizamento de discordâncias, encruamento e recuperação dinâmica inspirado nas contribuições de Kocks, Mecking e Estrin. O modelo proposto tem a sua estrutura matemática modificada para condições de temperatura variável, isto é, para cenários de incêndios.

Oct 1, 2019

* Kennecott Copper Corp. gets Charles R. Cox as president on Jan. 1. Mr. Cox is resigning his position as president of Carnegie-Illinois to take the new post with Kennecott, left vacant by the death of Mr. Stannard in September. •The ECA signed a contract in December to advance X3,600,000 to Newmont Mining Corp. to aid development of lead and zinc mines in French Morocco. The funds are to be repaid in lead and zinc for the United States' stockpile over a period of seven years. The mines are owned by the Societe des Mines de Zellidja, with which organization Newmont is associated. • Under the direction of John M. Brooks, Jr., general manager, the Matahambra mine in Cuba, will probably produce sufficient tonnage to make 4 million lb of copper per month during 1950. The grade is presently running between 7 and 10 pet. •S. H. Ash reports that the fatality rate per million-man-hr for the anthracite industry for 1949, through November, is 0.78. This is 15 pct better than that achieved during 1948, which was the lowest fatal injury rate in coal mining history. The first full year on record without a major disaster was recorded in 1949 (p. 34). •The Atomic Energy Commission has authorized the production of 200 lb of uranium metal for use under AEC license in non-Commission research projects. •A national survey of projected 1950 purchases of new machine tools, machine tool accessories, materials handling equipment, etc., just completed by the American Society of Tool Engineers reveals that, of the companies reporting, 80 pct state that they plan to buy either more equipment or the same amount as in 1948. • Armour Research Foundation is conducting investigations for the use of clay and shale deposits to make lightweight aggregates. The material is heated until it expands and forms material suitable for mixing with cement which it is hoped will be lighter, stronger, have better insulating qualities and will lower the cost of concrete. •In the first six months of 1949 the bituminous coal miners' average hourly earnings were $1.94 -as compared with X1.392_ national average for all manufacturing. Average annual earnings of full-time employees in the bituminous coal mines in 1948 were $3387 as compared with $2809 for all industry. •LaSalle Business Bulletin reports: "year ends on a rising trend in industry and trade ... nearly record-breaking demand from almost all sources keeps business high... most indicators but little below postwar peak... forces keeping activity high arestill powerful--changes in general business conditions likely to be slow and moderate." •Office of Internal Trade of the Commerce Department requests that technical data significant to the national security which is to be sent outside of the United States be submitted to it for an official opinion on the desirability of transmitting such information. This voluntary compliance program is part of our national security control. • Blast furnace slag reduced to 12 to 16 mesh is being used for sanding track at the Mont Coal mines of Armco. The slag replaces silica sand which caused silicosis. It has proved so effective and cheap that tests are being made to use the slag for rock dusting.

Jan 1, 1950

By Daniel K. Kim

The charge for the copper refinery is a mixture of anodes produced at San Manuel from BHP source concentrate and copper purchased from external sources. Control of unwanted impurities in the tankhouse - is very important and beneficial. Currently available removal/recovery technologies were reviewed for the control of bismuth and antimony levels in the electrolyte. Recent studies have focused on solvent extraction (SX) technology and generated successful results for the removal and subsequent recovery of bismuth and antimony. The SX system employs the reagent, ACORGA SBX-50, in conjunction with a patented high chloride stripping system. The latter enables recycle of the eluant, avoiding the high costs associated with conventional systems, such as regeneration of resin. Concerns over potential transfer of organics and chloride ion to the electrolyte were readily addressed, solved and demonstrated using conventional, established technology. This paper describes the benefits of electrolyte purification, the flexibility afforded by the SX system, the operational practices necessary for maintaining adequate control of bismuth and antimony impurities in the electrorefining environment and possibilities for future development /exploitation of the Zeneca SX system at the San Manuel refinery.

Jan 1, 1998