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This report, 27th in a continuing series1, describes Bureau of Mines research and technologic work on coal and related investigations during 1962. While the brief discussion in each section of the report presents only the highlights of Bureau work during the year, details of many investigations can be found in publications cited in this text. Other work, reported here for the first time, will be covered in greater detail in later publications. Recent trends in coal research and technology both at home and abroad were reviewed in several publications2. Bureau research, as in the past3, continued to stress improved methods of mining, preparing, processing, and using coal. The program included a wide variety of applied and basic studies for developing information useful to the coal mining industry and the coal consumer while promoting wise conservation and utilization of our coal resources.

Jan 1, 1963

Longwall minim; is a highly mechanized, high productivity mining method that is finding increasing applications in coal. Although the method would be highly advantageous in certain hard rock mining applications it cannot be applied in hard rock because no suitable cutterhead exists for such materials. The wedge longwall cutterhead is a, roller cutter device that is wedge-shaped, with cutters arranged to eliminate the very large normal force ordinarily required to cause such cutters to penetrate hard rock. However, the wedge geometry cannot be extended to a point: special nose cutters are needed to open a narrow slot for the wedge. This report describes the design, fabrication, and successful field testing of these critical nose cutters.

Jan 1, 1974

Ore from the Hill 50 Gold Mine, consists essentially of pyrrhotite, with minor amounts of pyrite, chalcopyrite, galena and gold, replacing "jaspilite." The gold is associated with the sulphides as shotty particles. About 8 per cent. of the particles are less than '0.010'mm.The Hill 50 Gold Mine, at Boogardie in the Murchison goldfield, about 300 miles north-west of Kalgoorlie, was first operated in 1898. From 1898 to 1917 it yielded 20,000 short tons of ore for a recovery of 6,225' fine oz. gold, equivalent to a recovery grade of 6.22 dwt. gold per ton.The present company since the beginning of its operations in September 1936 to June 30, 1954, produced 811,081 short tons of ore for a recovery of 242,554 fine oz. of gold, equivalent to a recovery grade of 5.98 dwt. gold per ton.The grade of ore (recovery grade) has shown a remarkable variation with depth. From the 120 ft. Ievel to the 300 ft. level, it averaged about 7.5 dwt. Au per ton. Below the 300 ft. level it declined, and from 300 ft. to 400 ft. averaged 4.9 dwt. per ton, falling further with increasing depth to about 4.5 dwt. per ton at the '600 ft. level.On the 820 ft. level the grade improved sharply to about 14 dwt: per ton, and this grade has persisted down to and on the 1060 ft. level.The orebody has been described by Finucane (1953) as a series of lenses of finely banded jaspilite conformably enclosed by greenstones. The jaspilite is tightly folded and faulted and intruded by dykes of felspar porpnyry.Mineralization is practically restricted to the jaspilite.

Jan 1, 1955

By J. G. Trowell, D. T. Magee

"IntroductionMANITOBA'S first recoverable oil was from the California Standard Daly 15-18 well in Lsd. 15, Sec. 18, Twp. 10, Range 27, W.P.M., completed early in 1951. This well also gave the first indications of commercial production in the Williston basin, which is centred in North Dakota and extends into southeastern Saskatchewan and southwestern Manitoba. Subsequent drilling in the Manitoba portion of the basin has revealed the presence of oil in more or less commercial quantities at various points in an area approximately four townships in width and eleven townships in length.Although completions are becoming fairlly widespread in the area,, the greatest activity is in the Virden district, with the focal point in the Daly field, approximately eight miles west •of Virden. This paper will deal with the various techniques used in the Daly field, where •completion problems have •been unusually troublesome. Techniques evolved there have already been used with success at other points in southwestern Manitoba.Daly FieldGeneralTo date, all production has been from the Mississippian limestone, which is encountered •at depths ranging from 2,300 to 2,500 feet. Pay thickness is •of the order of 100 feet. Core analyses indicate average porosity .of about 9 per cent but permeabilities, for the most part, are extremely low."

Jan 1, 1953

By J. C. Fowler

[This i.untra t hds bmii III c'IIILt fur till- past 1':?:u yrlr;, Till-- wurir pnrfor rw:it '. ,JS hlui.rn dawn Ilttf lit Iu i eel i ih?IS( S. 1 hesrt aIII, Phase I Candor tlri I a lest It) donurnSlrale SeiSrrlir nurihudS to hu USi!d lot ttlr? rti?tei thin and Iu" ainnl ul trapped rrlinc:rs hitting (-)it the roof with a harnrner, Phase I' Design and cunStrur.t a permanent Seismic monitor System to rrlunrtur roof (ails arm r:xploslun', III ,r 'Vol king mine. Phase III - Ire dII an an i i irr for sVstl rtl Ii i`'Smltur air quality in till, niitii iiH II ? ir,iti tin; niln !III ;I I ,, i; Phase I V - Conduct 11(21 d tests of the seismic IT IUnit UT ieq system fur a period nl two 11IUIIIIIS. Phase, V - Condirct three test periods of the seismic system over a period of six mimilis. Detailed reports covering the wurk. done in Phases I, 11, and IV have been i : . r tr I - i t report will, therefore, cuni.entrate on the work perfurmed in Phases III anti V.]

Jan 1, 1975

By Felipe das Dôres Machado

No processo de fabricação de aço, o distribuidor possui grande importância na questão limpeza inclusionária, principalmente, quando se trata da produção de aços limpos (clean steel). As inclusões podem afetar negativamente as propriedades mecânicas e metalúrgicas do aço. Estudos realizados em modelos físicos e/ou matemáticos vêm sendo aplicados com intuito de propor medidas que melhorem a capacidade do distribuidor na remoção de inclusões presentes no aço. Este trabalho tem como objetivo principal qualificar o escoamento de um distribuidor e quantificar a remoção de inclusões do mesmo. Um modelo físico de um distribuidor de lingotamento contínuo de tarugos construído em acrílico e que respeita a similaridade de Froude e Reynolds é utilizado para os ensaios. A quantificação das inclusões é realizada por meio de um ensaio que envolve um sistema de injeção de partículas de polietileno na entrada no distribuidor e outro sistema de coleta dessas partículas na saída do distribuidor no qual as amostras coletadas, posteriormente, são secadas e pesadas. Com os resultados obtidos pretende-se compreender o efeito dos parâmetros propostos sobre a remoção de inclusões e permitir a utilização de uma ferramenta capaz de avaliar a qualidade de aços no que se refere à passagem de inclusões na saída do distribuidor.

Jul 30, 2018

By Joseph J. Mgumbwa

Pillars are any structures left between two or more underground openings. The stability of pillars is normally considered to depend on shape (defined by width to height ratio), rock mass strength, extraction ratio, in situ stresses and the gross structural features (i.e. joints, contacts, faults etc). Recent experience has shown that pillar stability is also controlled by the relative orientation of the orebody with respect to the in situ principal stress. In inclined orebodies, pillars are loaded in compression and shear, thus creating unsymmetrical stress distribution. Failure mechanisms of these pillars are little known. This paper investigates the failure mechanisms of pillars under shear loading. Two dimensional elastic numerical modeling was used to examine the behavior of pillars in different orebody inclinations relative to the major farfield stress orientation. First, the paper reviews pillar design approaches including the empirical pillar design chart and uses numerical modeling to investigate the effect of the major farfield stress orientation on pillar stability. It is concluded that the empirical pillar design chart be used with caution, and that for orebodies under shear loading mine planning and design should take this into consideration since such geometrical orebody/stress relations put mine structures at higher risk of instability.

Oct 1, 2010

By Heloíza Döering Gasparin

Os efeitos de elevadas temperaturas e do tempo de exposição sobre as propriedades mecânicas de um ferro fundido cinzento hipoeutético foram avaliados em amostras de dois ferros fundidos da classe FC300, de mesma base, com diferentes percentuais de molibdênio. Ensaios de tração até ruptura a quente foram realizados em corpos de prova com diâmetro de 10 mm, usinados de um pino bruto de 30 mm de diâmetro. Os ensaios foram realizados a frio (temperatura ambiente) e a quente (200°C, 300°C, 350°C, 400°C, 450°C, 500°C e 550°C). Os tempos de exposição a elevadas temperaturas, após homogeneização térmica do material, foram de 0, 60, 90 e 120 minutos. As amostras com maior percentual de molibdênio (0,27% em peso) apresentaram melhores propriedades mecânicas para todas as condições ensaiadas. De acordo com a literatura a redução na resistência mecânica com a elevação da temperatura é atribuída à ocorrência de decomposição da perlita, como resultado da difusão do carbono vindo da cementita às lamelas de grafita, que é o responsável pelo aumento da quantidade de grafita no material. As análises metalográficas evidenciam a ocorrência deste fenômeno. Aumentos no tempo de exposição a temperaturas elevadas também contribuíram para a degeneração da perlita.

Aug 7, 2018

By Ma Lijuan, Zhang Yubing, Wang Bo, Sun Huilan

The effect of lime ratio on phase composition and alumina leaching property of MgO-contained calcium aluminate clinker were investigated by analytical reagent, the XRD analysis of its mechanism was discussed. The results showed that: when the sintering temperature was 1350 ℃, C/A was 1.4, A/S was 1.3 and the content of MgO was 4%, the increase of the C/A promoted the formation of C12A7 and restrained the formation of Q-phase. The alumina-leaching ratio of the clinker (A/S was 1.3) was increased from 74.33% to 91.34% when the content of CaO was 5.21%.

Jan 1, 2015

The poor reconciliation between the values of estimated and actual grades can cause major economic losses to the mining industry. In a mining operation grade reconciliation is comparing the values of estimated grade calculated in exploration stage with actual grade obtained from blastholes' data. Many different factors affect the degree of reconciliation in a mining operation. In this paper we investigate the factors related to estimated grade which affects the reconciliation process in the exploration stage of the orebody. These factors are the sources of uncertainty in the rest of mine life. In this area the most important factors are inherent variability, statistical uncertainty and systematic uncertainty. A probabilistic model was presented to model each source of uncertainty. The implementation of proposed model was checked and its validity was investigated using real data in an iron open pit mine in Iran.

Dec 6, 2010

By D. G. Swarthout, J. W. Savage, R. W. Guard

The Nb-N constitution diagvam has been examined from 1100° to 1450°C at 1 atm N2 pressure. On the basis of- our work plus that of Brauer and coworkers the stable nitvide Phases are: a) a solid solutlion, basic niobium (bcc) with nitrogen contained interstitially; NbN,, x = <0.40; b) ß NhNx,x = 0.39 to 0.45; hexagonal (W2C type) (NbzN); a =3.058A,c = 4.961 + 0.001A c) y NbNx x = 0.75 to 0.80; tetragonal (distorted NaCl type) (Nb4N3); a = 4.386A,c = 4.332 + 0.001A; d) 6 NbN,, x = 0.88 to 0.91; cubic (NaCl type); a = 4.3885 + 0.0007A; e) E NbNx x = 0.92 to 1.00; hexagonal (Tip type); a = 2.958A, c = 11.272 * 0.0015A. In addition, a metastuble transition phase 6&apos; has been observed and occurs only during the transition 6 — E. 6&apos; NbN has these distinguishing parameters: NbNx,x = 0.96; hexagonal (anti-NiAs type); a = 2.94A, c = 5 .46A. The high-temperature phase fields in the system are governed by two reactions: a) 6 + Y + E, a entectoid reaction occurring at 1270" ± 20° C; b) o + N2 = E, a 2 012 1 reaction occurring at 1370" ± 20° C. As part of a study of the electronic low-temperature. properties of transition metal nitrides, a number of specimens of niobium nitride were prepared. Preliminary observations on these specimens showed several points of disagreement with data already in the literature. It was, therefore, decided to determine the constitution diagram for the Nb-N system between 1100" and 1450°C. The objective of this research was to define the temperature and composition regions of stability of the various phases and to explain the differences among previously proposed diagrams. Review of Previous Literature. The research on the Nb-N system to 1964 has been summarized by storms.&apos; Although he does not present a phase diagram, his review covers the research on the system thoroughly. One of the earliest works on NbN is that of Ascher-mann and coworkers2 who studied the superconductivity of the cubic 6 NbN. Subsequent work by Horn and ziegler,3 Cook, Zemansky, and Boorse,1 Rögener:5 Schroder6 and sellmaier7 has qualitatively confirmed the first results on superconductivity, although their methods of preparation differed considerably. The constitution diagrams proposed for the system by Brauer and Esselborn8 and Elliott9 are shown in Fig. l(a)and (b). The diagram in l(a) has been modified by more recent results in Brauer&apos;s laboratory (private communication). Although 6&apos; is shown on this diagram, Brauer has indicated that he now believes 6&apos; to be a metastable phase in the temperature range shown. The diagram of Elliott, Fig. l(b), is based primarily on the results of Elliott and Komjathy10 on ni-trided niobium strip or rod specimens examined by X-ray diffraction and metallography. It will be noted that these proposed diagrams are in conflict with respect to the temperature and composition ranges of

Jan 1, 1968

By Thompson D. R, Milton R, Perry K. M A

From the Department for Research in Industrial Medicine (Medical Research Council), The London Hospital; and the De Havilland Aircraft Company:M.R.C. INVESTIGATIONS IN 1936In 1936 the Industrial Pulmonary Disease Committee of the Medical Research Council investigated both clinically and radiologically a group of fifty workers who had been exposed for a number of years to the inhalation of alumina in the reduction factory of the British Aluminium Company. The results are shown in Table 1.They also considered the sickness records of all the workers (Hill, 1936), as compared with those in other parts of the factory (Table 2).

Jan 1, 1945

Blasts should be designed so as to maximise the percentage of charges which shoot to a free face (Le, to a pronounced rock/air interface).Free faces should be rough, parallel and reasonably near to blastholes and, very importantly, concavely&#183;biplanar relative to the charges (see Fig. 6b). The presence of biplanar free faces requires that each charge fragments and detaches its quota of the burden rock before the detonation of:1. later-firing adjacent charges in single-row blasts, and2. dependent charges in multi-row blasts.In multi-row blasts, biplanar faces are best achieved:1. by drilling blastholes on equilateral triangular grids,2. by selecting a VI, V2 or V3 initiation sequence, and3. by using down-the-hole delays.Biplanar faces start to be created only when the conventional value of effective blasthole spacing/effective burden distance (Se/Be) increases beyond about 2.4. Values of Se/Be less than about 2.4 result in planar free faces. Where biplanar faces are created, conventional values of Se/Be are invalid and appreciably greater than real values of Se/Be.

Jan 1, 1986

By William M. Schafer

Forage plots were established on agricultural lands contaminated by acid mining waste. The acid produced through oxidation of pyrite and other sulfides caused elevated solubility and plant availability of copper, zinc, and arsenic which killed vegetation and polluted surface and groundwater. Soil amendments including agricultural lime (CaCO3), hydrated lime (Ca(OH)2), phosphorus, and organic matter were used to reduce the toxicity of metals. Several acid-tolerant grasses were used to vegetate the amended soils. Various soil extraction techniques were used to see which best correlated with vegetation performance. The extractions corresponded to three "forms" of metals in soil including soluble (water-saturation extract); plant-available/weakly adsorbed (DTPA extract); and total (HNO3/H202 extract). Of the extractants tested the DTPA levels appeared to correlate best with metal levels in plant tissue. The DTPA soil extractant serves as a useful tool in predicting potential phytotoxicity of mine waste materials.

Jan 1, 1989

By Olívia Cristina Petriz Monteiro

A Companhia Siderúrgica Nacional (CSN) possui uma Oficina de Manutenção Mecânica Central que fornece serviços de reparo, fabricação e manutenção de conjuntos mecânicos e componentes. A usinagem é um dos setores de maior demanda durante o reparo na Oficina e é considerada o grande gargalo entre as etapas de reparo/fabricação. Na busca por uma melhora na qualidade do atendimento e dos serviços prestados, o trabalho teve como objetivo identificar e implementar um novo sistema de medição para o Controle de Qualidade da Oficina Mecânica, reduzindo a demanda de inspeções dimensionais e geométricas para o setor de Usinagem. Com a compra dos instrumentos de medição tridimensional, o Laser Tracker e o Braço de Medição, foi possível aumentar a disponibilidade da usinagem, diminuir o tempo de inspeção de peças, acelerar o processo de decisão dos reparos, reduzir o tempo de entrega dos equipamentos, aumentar a confiabilidade das inspeções, além de e efetuar eventuais serviços de medição em campo.

Aug 8, 2018

By Rafaela Pereira Batista

O consumo de refratário na produção de aço é parte significativa no custo de produção. Por este motivo, é usual nas aciarias a oxigênio empregar os processos de slag splashing e slag coating, visando à formação de uma camada de escória sobre o refratário de MgO-C. Os dois procedimentos diferem, principalmente, pelo seu objetivo: o slag splashing visa a proteção do revestimento como um todo, enquanto o slag coating busca proteger principalmente o fundo do conversor e as ventaneiras do sopro combinado. Para a efetividade destes processos, é necessário adequar a escória para que a camada formada resista a temperatura e condições do processo, seja compatível quimicamente com o refratário e tenha boa aderência ao tijolo do forno. Este trabalho apresenta os resultados do desenvolvimento de um modelo matemático que orienta quanto a adição para o tratamento do revestimento refratário do conversor pela projeção de escória.

Oct 30, 2017

By Reed S. C. Rogers

There is recent evidence that high frequency screening can be a viable alternative to hydrocyclone classification for a wide variety of grinding applications. However, since high frequency screening is a relatively new development, the decision to use screens generally must be based on full scale screening tests of a slurry material of interest. In this paper the authors employ mathematical simulation models as an aid to evaluating the use of screens versus hydrocyclones for closed circuit fine grinding. This approach is validated in a pilot plant study and then demonstrated for the design of full-scale grinding circuit, including classifier cost comparisons. For the case of maximum production rates versus product size, without a constraint on fine product solids densities, results indicate that screening with Derrick sandwich type cloths can give higher grinding circuit production rates with more narrowly sized products than when hydrocyclones are used. These results are explained in terms of the bypass and Sharpness Index of the respective classifier partition curves. Classifier cost comparisons for the full scale circuit show that although the installed cost of screens is substantially higher than equivalent capacity hydrocylone operations, even modest increases in circuit capacity caused by screens; can significantly reduce total grinding costs.

Jan 1, 1985

By H. N. Egan

Faced with a severe disposal problem of their fines from a coal mine in the heart of the Appalachian Mountains of extreme eastern Kentucky, Eastern Coal Corporation has built a special plant to pelletize the fines into high quality coal pellets meeting the requirements of the metallurgical market. These low-ash, low-sulfur pellets measuring 3/4 x 3/8 in. contain less than 1.5% moisture and have the same stability as raw coal of the same size. Although Eastern Coal is mining 6000 tpd, the company had, until recently, no provision to recover the fine coal which was included with the plant effluent pumped to a 12-acre refuse pond. The pond, impounded behind the coarse refuse dump, rose 15 ft last year and obviously no pond can stand many years at this rate. Limited pond space in this rugged area of steep hills and narrow valleys dictated a revised disposal method.

Jan 11, 1967

By Karl A. Gschneidner

The magnetocaloric effect has been known for 120 years and has been utilized for cooling about 70 years. But in the last four years significant advances have been made to show that magnetic refrigeration is a viable and competitive cooling technology. Most of the work has focused on reciprocating devices, but rotary apparati are being developed. To date the magnetocaloric properties have been characterized for more than 200 materials. The magnetocaloric effect behaviors have been classified into three types of behaviors. The most common one is found in magnetic materials which exhibit a second order magnetic phase transition. Magnetic materials which exhibit a first order magnetic phase transition account for the second group of materials. Materials which exhibit multi-magnetic phase transitions make up the third group. The best candidate materials for magnetic cooling over the range from -4 to -1 350 K are also presented.

Jan 1, 2002

By Isobel Yeo, Luca Cocchi, Sven Petersen, Nico Augustin, Sean Plunkett, Ingo Klaucke

Exploration for seafloor massive sulfides is currently mainly focused on investigation for active hydrothermal vent fields. However, most of the resource potential is thought to be related to inactive, large deposits that had enough time to accumulate sufficient tonnage. At the same time, ageing of these deposits will ultimately result also in burial acted by either sediments and/or volcanic deposits. We currently lack the technologies to explore for these deposits in a time- and cost-efficient manner. In the fall of 2012 we used a number of AUV-based technologies to explore and image a sulfide occurrence at the Palinuro Volcanic Complex in the Tyrrhenian Sea (Mediterranean Sea; Fig. 1) where sampling and drilling have documented a buried polymetallic barite-pyrite dominated site (Petersen et al., 2014). Sulfide mineralization is here covered by volcaniclastic and pelagic sediments and only red sediment staining and the presence of few tubeworm bushes indicated recent hydrothermal activity - black smoker venting is absent. We used AUVbased high-resolution bathymetry, sidescan sonar imaging, subbottom profiling, as well as magnetics to describe, in a quantitative way, the previously known sulfide-bearing areas as well as to successfully explore for new hydrothermal sites including large chimney structures (Figs. 2). Additionally chemical sensors (CTD, Eh, turbidity) investigated the water column for signs of hydrothermal activity in areas not previously investigated, but at the end, only weak anomalies were found in the southern part of the summit.

Sep 1, 2014