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By Larry Hopkins

The molten metal circulation pump has become a staple for melting aluminum in reverberatory furnaces. The forced convection that is created in the melt efficiently provides circulation while dramatically improving melt rates, lowering fuel consumption, extending refractory life, and providing metallurgical homogeneity. Two metallurgical guidelines that are important to many casthouses are molten metal inclusion levels and hydrogen gas content. In order to improve molten metal quality, furnace and casting practices must 'manage these molten metal defects, Today specialized in-line degassing and filtration equipment is used downstream of the furnace to accomplish these tasks. In contrast, the molten metal gas injection pump has metallurgical contact time in the process for hours during the charging/homogenization cycle. The qualitative benefits of employing a gas injection pump to "pre-clean" are outlined and discussed against historical empirical information obtained with alternate methods. Further, a recent study quantifies the merits of this gas injection technique as an effective molten metal quality improvement tool. Specifically, the effects on inclusion level as determined by PoDFA?, gas content as determined by A1SCAN? sampling and alkali metal content as determined by spectrographic analysis are examined in relationship to various gas feed compositions and flow rates.

Jan 1, 1995

By S. Don Brown

Between 1987 and 1988, the Bureau of Mines studied the mineral resources of the White River National Forest and part of the Arapaho National Forest to appraise the resources present and to determine the types of deposits, and their location, that could be mined economically if sufficient demand and metal prices existed. The study included a comprehensive literature search and a limited amount of field investigation of minerals and mining activity in and near the Forest. Mineral resource information indicates that in the Gore Range the area between Tennessee Pass and Gilman may contain large base-and precious-metal deposits, and could be the focus of exploration activity in the near future. The Breckenridge mining district was found to have a moderate to high likelihood for mineral exploration and possible development of gold. Recent exploration and minor development work has occurred in several other areas: Montezuma, Kokomo-Tenmile, and Upper Blue River districts, and portions of the Sawatch Range. Limestone, marble, sand and gravel, rock for crushed aggregate, and other industrial rocks have been recently mined or Quarried in the Forrest, and will likely be mined or quarried in the near future. Currently coal is being produced at one mine in the Forest, and extensive identified coal resources are located in the Forest. Parts of four known gas fields lie within the Forest west of Glenwood Springs; there is current production at one field.

Jan 1, 1990

By Dale R. Spangenberg

This Bureau of Mines Information Circular on phosphate is one of a series of minerals availability commodity directories. Nonconfidential information from the Minerals Availability Program data base covering 148 domestic and 103 foreign phosphate properties and deposits has been abstracted for use in this directory. Abstracts include applicable data on location, published reserves and resources, geology, mine and beneficiation systems, and operational information.

Jan 1, 1983

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By Ângela Selau Marques

A fabricação de matrizes para forjamento a quente vem sendo estudada com maior atenção nos últimos anos devido à necessidade de fabricação das ferramentas com maior rapidez e menor custo, estudo do processo de usinagem, com melhores propriedades mecânicas a fim de aumentar sua vida útil. Para atender as atuais necessidades do mercado são utilizados softwares de CAD e CAM e principalmente de máquinas CNC, que além da rapidez garantem a qualidade da usinagem das matrizes. O objetivo deste artigo é demonstrar, através de um estudo de caso, as etapas para a fabricação das matrizes superior e inferior, para forjamento a quente. Foram utilizados sistemas de CAD e CAM, o SolidWorks para modelagem da peça e das cavidades da ferramenta, e o software Edgecam para a programação e simulação da usinagem. As facilidades obtidas com a integração entre os sistemas CAD/CAM e máquina CNC conferem a manufatura de ferramentas muitos benefícios, dentre eles destaca-se a rapidez com a qual se pode fabricar uma matriz.

Aug 8, 2018

By G. B. Quaye

The deep level gold mining environment is characterized by high stresses that give rise to intense mining induced fracturing of the rock mass surrounding the stopes. In a geologically disturbed region where the intensity of mining induced stress fracturing is high, the degree of faulting and/or the frequency of other geological features such as joints may pose serious strata control problems. Unfavourable intersection of these discontinuities namely, faults, joints and mining induced stress fractures tend to divide the immediate hangingwall into unstable keyblocks which, if not supported, may result in extensive falls of ground. Effective support strategies therefore demand detailed investigation of the predominant inclinations and orientations of these discontinuities. The orientations and inclinations of these discontinuities surrounding a deep level stope have been measured. The results are projected onto the lower hemisphere of a stereographic net to determine the factors that contribute to the falls of ground in the stope. The analyses reveal that unfavourable intersection of these discontinuities divides the immediate hangingwall into unstable wedges that may become dislodged between support units.

Jan 1, 1998

By James L. Ash

This report contains the results of a technical and economic evaluation of conceptual systems for the underground mining, rubblization, and in situ retorting of deep oil shale deposits. Study efforts were first directed towards evaluation of the applicable geology, associated minerals, rock mechanics, in situ retorting, access mining, ventilation, rubblization, safety, and environmental impact factors. Conceptual systems were synthesized and then evaluated against these factors from both a technical and limited economic viewpoint. The results of these evaluations were then analyzed and, based upon this analysis, the following two systems were selected for further study: System II: Room and Pillar-Vertical Drill and Blast System IV: Tunnel Boring-Horizontal Ring Drill and Blast Due to the large number of variables to be considered, a computer program was developed and utilized to provide data for the cost trade-off studies and economic analysis. Results of the early computer runs indicated the value of the tool available? in the computer program and led to an extension in the contract to determine the sensitivity of the systems to several of the more apparent significant variables. These results in turn led to a refinement in the design assumptions and a better understanding of the technical and economic options available to an owner-operator of a Vertical Modified In Situ Shale Oil Extraction System. This report is submitted in fulfillment of the requirements of Contract Number 50241073 by Fenix & Scisson, Inc. to the Denver Mining Research Center, United States Department of the Interior, Bureau of Mines. Work was completed as of November, 1976.

Jan 1, 1976

By Murali Thirukkonda, Rahul Shah, Srinivas Tangrila, Shankar Rachakonda, Jan Kajuch, Arthur Gurson

"High-temperature superconductors have potential for a variety of applications such as power generators, superconducting magnets for mine sweepers or ship propulsion motors, and magnetic levitation transportation systems. Interest in the use of superconducting wires and tapes increased dramatically after the discovery of high-critical-temperature (high-Tc) oxide superconducting compounds, which offer operating temperatures above that of liquid nitrogen. Several techniques have been proposed to produce commercially viable high-Tc oxide based superconducting wires. One of the promising methods involves multi-pass powder-in-tube (PIT) wire drawing followed by rolling and heat treatment. This work focuses on the development of a numerical model to simulate the PIT drawing process for fabrication of long lengths of silver sheathed Bi-2212 superconducting wires. The finite element based model was used to predict densification of the oxide powder, wire drawing forces, and silver sheath thickness during drawing. A cap-type pressure dependent constitutive equation was implemented in the model to simulate the powder behavior. The model incorporated experimentally obtained material data for the silver and powder. Results indicate that powder densification is increased by decreasing the initial silver thickness and increasing the silver strength. Data from wire drawing experiments were used to verify model predictions. IntroductionSuperconducting wires and tapes can be used to carry large dc currents with no measurable loss due to resistivity. When used in superconducting magnets for power generators, motors, levitation devices, magnetic detectors, or energy storage devices, they could potentially result in significantly reduced energy losses. In the past, most prototypes were tested in liquid helium at 4.2K [1]. However, the necessity to provide liquid-helium cooling systems proved to be a serious limitation in commercialization. In 1986 high-critical-temperature (high-Tc) oxide superconductors were discovered [2], which could allow for higher operating temperatures above liquid nitrogen (77 K). Since then, both academia and industry have concentrated their efforts on the development of high-Tc oxide superconducting wires, tapes and coils. As yet, large scale fabrication of long lengths of these wires with the required current carrying capacity and mechanical properties remains an enormous challenge."

Jan 1, 1994

By W. J. Birch, R. Farnfield, S. Hosein, C. Johnson

Modern smart phones include accelerometers based on MEMS (Micro Electro Mechanical System) technology giving the possibility to measure both acceleration and orientation. The widespread use of such phones has driven technological development to such a degree that it is now possible to obtain a triaxial accelerometer unit, that also include signal conditioning and analogue to digital conversion, in a package smaller than 1 cm2 (1/2 sq.in) for a relatively low cost.

Feb 6, 2023

By Lucas Kling e Silva

A deformação plástica de aços acompanha mudanças irreversíveis da microestrutura, que podem ser consideradas como o estágio inicial do processo de fratura. No entanto, detectar, monitorar e avaliar previamente, estados de dano e pequenos defeitos, de forma não destrutiva, ainda se mostra desafiador. Foi reportado na literatura o fenômeno do surgimento espontâneo de fracos campos magnéticos em aços estruturais e em oleodutos, que são originados devido a tensões mecânicas heterogêneas ou térmicas. Esta observação não é associada com transformações de fase induzidas por deformação e parece ser uma ferramenta promissora para a caracterização prévia de danos em aços ferromagnéticos. Para proporcionar uma melhor compreensão das bases físicas deste processo, foram observadas as microestruturas magnéticas de tais materiais e as mudanças ocorridas nos domínios magnéticos dos mesmos após sofrerem deformação plástica. Para isto foi utilizado um meio de solução coloidal com partículas superparamagnéticas na escala nanométrica (ferrofluido) que proporcionou, através da técnica Bitter, observar não apenas uma mudança de tamanho dos domínios magnéticos do material, mas também modificações em sua morfologia. Foram estudados neste trabalho aços ferríticos com as respectivas concentrações de carbono em sua composição: 0.08%; 0.22% e 0.45%.

Oct 30, 2017

By J. Crummy, I. K. Anderson, A. J. Hall, R. S. Haszeldine

Bedrock gold mineralisation has been located in association with an extensive float train 25 km west of known alluvial gold. It is in the form of open, matrix-supported breccias comprising pyritic quartz/sericite clasts in a vuggy, cherty chalcedonic and crystalline quartz matrix. Fluid inclusions in pyritic clasts indicate trapping temperatures for gold mineralising hydrothermal fluid of 170-240 degrees C. This mineralisation could represent the upper part of a feeder zone to an exhalative hydrothermal system. It is possible that other high-level feeder zones could be preserved elsewhere in the area. Deep weathering of such a system could provide a source for the alluvial gold localities near Helmsdale. It is suggested that east and central Sutherland presents good prospects for exhalative epithermal gold mineralisation and the associated feeder zones

Jun 19, 1905

By José Flávio Viana, Alexandre Alvarenga Palmeira, Darlan Rodrigues Azevedo

O processo de dessulfuração do ferro gusa é uma etapa de grande importância para a fabricação do aço. Diante da necessidade cada vez mais exigente de aplicações nobres, dos aços, faz-se necessário o desenvolvimento e estudos buscando maior eficiência e custos operacionais otimizados para melhores resultados deste processo. O carbureto de cálcio é um insumo utilizado como matéria prima dos agentes dessulfurantes. Através do microscópio de varredura e o EDS, buscou-se estudar e entender o mecanismo de reação do carbureto de cálcio no processo de dessulfuração do ferro gusa líquido, sendo realizado o estudo no Laboratório de Ensaios e Análises em Materiais - LAMAT do SENAI de Itaúna – MG, em conjunto com o setor de pesquisa e desenvolvimento da Tecnosulfur S/A.

Oct 1, 2019

By Zhenzhong Bian, Ruiyang Zhang, Xiaofeng Zhong, Zhangxuan Ning, Yuanping Zhang, Jie Lu, Airan Zhang

This study addressed the separation and recovery of vanadium(IV), iron, and titanium from synthetic and real leach solutions of vanadium-bearing titanomagnetite using extractant P204 (di-(2-ethylhexyl) phosphate) and P507 (2-ethylhexyl hydrogen- 2-ethylhexyl phosphonate). Based on the speciation analysis of vanadium in sulfuric acid medium, the single-stage extraction efficiency of vanadium, iron, and titanium was 94.21%, 3.45%, and 5.32%, respectively, under the optimal extraction condition of P204-P507 concentration of 15% (v/v), P204 to P507 ratio of 3:1 (v/v), TBP (Tributyl phosphate) concentration of 5%, sulfonated kerosene concentration of 80%, initial pH of 1.8, contact time of 8 min, and phase ratio (O/A) of 2:1. By confirming the predictions of the McCabe-Thiele diagram, a five-stage countercurrent extraction was carried out and the desirable extraction efficiency for vanadium reached 98.13%. The maximum co-extraction coefficient and distribution ratio of vanadium were 2.58 and 26.23, respectively. The stripping efficiencies and concentrations of a vanadium-rich solution by three stages of countercurrent experiments with 20 vol.% sulfuric acid reached 99.14% and 0.58 g/L, respectively, while almost all of the titanium remained in the organic phase. The mechanism of synergistic extraction between hydrogen ions of P–O–H and VO2+ in acidic conditions was confirmed by ATR-FTIR spectroscopy and molecular structure derivation. Besides, the separated impurity ions ( Fe2+) after oxidation, precipitation, and roasting process form a qualified iron oxide pigment with a total iron content of 97.2%.

Apr 25, 2023

Discussion of the paper of R. J. COLONY, presented at the New York Meeting, February, 1921, and issued With MINING AND METALLURGY No. 169, January, 1921. R. J. COLONY (author&apos;s reply to discussion).-The work of Sosman and Merwin on the system lime-ferric oxide, mentioned by Mr. Rankin, was not overlooked. When studying portland cements and portland-cement clinkers petrographically, however, the lime-iron compound was difficult to correlate with the very definite dicalcium ferrite described by those investigators, which possesses such well-defined optical properties. In portland cements, the calcium ferrite (or ferrate?) is an indefinite, fuzzy, and generally amorphous, or apparently amorphous substance that is distributed interstitially with respect to the other grains, from which it was very difficult to derive any satisfactory results. For this reason, the writer, tentatively, chose to regard it as related to the aluminate, and assigned to it the composition 3CaO.Fe203, which may be incorrect, however, as Mr. Rankin suggests.

Jan 8, 1921

By Thomas M. Gurtowski

This paper presents a summary of allowable bearing pressures and skin friction values that have been used to design drilled pier foundations for support of high-rise structures in downtown Seattle, Washington. These design parameters are based upon a review of geotechnical reports and records of more than 20 building projects. The following pages present a description of the soils encountered at these sites including foundation bearings soils, and design bearing and friction values. The accumulated data is summarized in Table 1, and the locations of the buildings are shown in Figure 1. A detailed description of the construction of two belled drilled piers are presented illustrating typical methods and procedures used in downtown Seattle. The two cases are from the Washington State Convention and Trade Center (WSC&TC). SEATTLE AREA SOILS The Puget Sound area was subjected to several major glaciations during the Pleistocene Epoch. Glacial ice originated in the cordilleran and coastal mountains and the Vancouver Range of British Columbia. The maximum southward advance of ice reached the area about halfway between Olympia and Centralia. As a result of these glaciations, the Puget Lowland was filled to significant depths by glacial and non-glacial sediments during the Pleistocene.

Jan 1, 1990

By Gordon B. Brox, Joseph F. Mcaleer, Charles C. Goddard, Edward P. Shea, Robert G. Ingersoll, Lester G. Zeihen, George J. Burns, John M. Guilbert, Richard N. Miller, Charles Meyer

The Boulder batholith is a composite intrusive in which the Butte quartz monzonite is the dominant rock type. Quartz porphyry dikes intruded the quartz monzonite in directions which were subsequently followed by the eastwest- striking Anaconda system of veins, the earliest major veins in the district. Anaconda veins are faulted by northwest-striking veins of the Blue system, which are most prominent in the central third of the district. Anaconda veins are the major producers in the western third of the district and also in the eastern third, where the "horsetail" zones break off from them. Individual oreshoots are thousands of feet long as well as deep on both systems of veins, but they are generally more persistent and thicker on the Anaconda veins. Viewed broadly, the mineralization in the big veins is arranged in crudely concentric zones of zinc and manganese around a central zone of copper. Only slightly offset from these zones, but earlier structurally, is a zone in which quartz-molybdenite veinlets are prominent. This zone tops at about the 2800 level and widens downward. The pattern of distribution of Cu-Fe-S series minerals in the large veins of the copper zone is not symmetrical with respect to the metal zones. There is a fringe of chalcopyrite-bornite all around the copper front. However, within the copper zone, pyrite-chalcocite-enargitecovellite- digenite assemblages are prevalent near its eastern edge from the 3800 level to the surface, whereas deep on the large Anaconda veins in the western part of the copper zone, chalcopyrite is dominant. Here the chalcopyrite grades upward into bornite-chalcocite ores and eastward into the high-sulfur assemblages of the Leonard mine. Sericite-biotite-K-feldspar alteration envelopes, containing up to about 2 per cent copper as chalcopyrite, are present on some of the quartz-molybdenite veinlets at deep mine levels in the molybdenite zone. These envelopes contrast sharply mineralogically and chemically with the later sericitic and argillic alteration envelopes around Main Stage veins. K'0-Ar'0 ratios indicate that they may be older by about 4 m.y. Secondarily enriched copper ores are mined in the Berkeley pit in the southeastern part of the district. At the present time they account for about half of Butte's production of copper.

Jan 1, 1968

By Luzheng Chen

Pulsating high-gradient magnetic separation (PHGMS) of fine hematite from tailings was studied using a pilot PHGMS separator to investigate the possibility of its application in industry. The results of this investigation indicate that PHGMS is effective for recovering fine hematite from the tailings and greatly improved the separation performance compared with the conventional high-gradient magnetic separation at the same conditions. By applying the pilot separator with a 1-mm rod matrix to a tailings containing 28.76% Fe, a concentrate assaying 54.35% Fe with 35.89% recovery was achieved. It was found that the separation performance of the pilot separator closely correlates with the main pulsating parameters, i.e., pulsating stroke and frequency. It was also found that a change in the wire diameter of the rod matrix from 2 to 1 mm causes a weak drop in concentrate grade but results in a considerable rise in recovery. This finding proves that the improved performance achieved by the pilot separator is attributed to the pulsating of slurry and to the use of a 1-mm rod matrix. When the first commercial SLon-2500 PHGMS separator with a 1-mm rod matrix was applied to recover fine hematite from the tailings, the results duplicated those achieved with the pilot PHGMS separator.

Jan 1, 2009

By Nadya Michel, Daniel Gros-Jean

This is a true story. Names have been changed to illustrate the importance and impact of carbon monoxide risk management in explosive blast projects and the community « Honey I’m not feeling good…” “What is going on Michael?” – – Michael was not answering so Julia, who was on the third level of the magnificent house, hurried down the stairs to check up on him in the basement. Today was day 2 of the construction work of the bathroom, yesterday they had excavated all the space for the shower. She started to breathe heavily as she was approaching the bathroom and saw Michael unconscious on the floor. “Michael!” – Julia immediately dialed 911. She opened a window since the air was heavy and went by Michael to hear him breathe and take his pulse. The paramedics took Michael on a stretcher and rushed him to the hospital. “I’m feeling dizzy” she thought to herself a couple of hours after the incident, and heard Matthew say: “Mom, I’m feeling sick”. Suddenly, she felt like she would pass out and felt in danger but couldn’t move. She desperately searched for her cellphone and dialed 911 but couldn’t speak. The dispatcher sent the firefighters and paramedics to the GPS location that was appearing on the screen and the emergency team was alerted that it was a second call in hours at the same address. When the firefighters arrived, they had to force the door to enter and found Julia in her bedroom on the third floor and Anette and Matthew also unconscious in their bedroom, lying on their respective bed. There was no smoke but on their multigas meter, carbon monoxide (CO) peaked at 1500 ppm on every level of the house, which is abnormally high.

Feb 6, 2023

By G Boyd

The Nokomai Gold Mining Project commenced production in January 1992. The Project continues a history of mining in theNokomai Valley which extended from 1863 to 1942. L &amp; M Mining Limited have held interests in the valley since 1980. In 1990 the Nokomai Joint Venture was formed with the Hore family, the owners of Nokomai Station, to mine a large alluvial gold resource in the valley. The mine is located adjacent to the Mataura Brown Trout fishery and required extensive environmental studies prior to granting of permits. The mine is budgeted to work for 20 months, processing 460 000 m3 of wash material. During this period, contract miners, Downer Mining Limited, will move in excess of seven million cubic metres of overburden from the deposit.

Jan 1, 1992