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By N. Wang, A. I. A. Salama

"An index to evaluate the amenability for processing of different coals is implemented. The index is based on the well-known Mayer-curve or M-curve. The index is superior to other existing indices and is implemented using Microsoft-Excel™. Several coals are used to demonstrate the implementation of the index proposed.IntroductionIn 1950, Mayer introduced a curve that carries the information embedded in the fir s t three curves or ash curves of the conventional washability tables and curves (Peng et al., 1979; Osborne, 1988). The curve was labeled the Mcurve (abbreviation for Mittlewertkurve in German or the Mayer- curve). The main idea behind the curve is to use the ordinate for the cumulative mass and the abscissa for the ash (attribute) mass. Specific slopes on the resulting curve represent the cumulative float, cumulative sink, and elementary ash (attribute) contents (Mayer, 1950, 1953, 1957; Venkatesan, 1975; Osborne, 1988; Salama, 1989). Beyond the ash values, the curve carries graphical information that can be used in evaluating coal processing characteristics. Consequently, it becomes possible to present several raw coals on a single diagram, thus making it easier to compare their processing characteristics. This is particularly useful in comparing various size ranges of raw coal or the same size range from different seams. Therefore, the M-curve is adopted as a vehicle for developing the “processing (washing) characteristics index” implemented in this paper."

Jan 1, 2001

By Raphael Lemos

Durante o ano de 2008 foram observados diversos “Gap’s” no processo de lubrificação, tais como: alto consumo de graxa, lubrificação em excesso, degradação de sistemas centralizados, ausência de procedimentos, mão-de-obra sem o conhecimento adequado, entre outros. Dessa forma, o processo de lubrificação foi separado em cinco grandes grupos de atuação, sendo eles: seleção de lubrificantes, gestão do processo de lubrificação, sistemas centralizados, contaminações e vazamentos. Foram aplicadas as ferramentas do MASP (Método de análise e solução de problemas) sendo a primeira delas o "Brainstorming", nos valendo das observações realizadas no Laminador de tiras a quente nº 2. Em sequência foi definido e implantado o plano de ação. Os resultados obtidos após as ações foram: a redução do tempo de parada associada a problemas de lubrificação dos equipamentos do LTQ#2, redução média de consumo de graxa no laminador de - 6.277 kg/mês, quando comparamos a média de consumo do período de Novembro de 2010 a Outubro de 2013, frente ao consumo atual no período de Novembro de 2013 a Outubro de 2014, totalizando uma redução média de aproximadamente - 75.321 kg nos últimos 12 meses.

Aug 16, 2017

The authors describe two stratiform intrusions within a two miles thick ophiolite belt, one of the many ophiolite (serpentine) belts of the eugeosynclinal sequences of the Kalgoorlie System (metamorphic age c.2700 million years). Unusually good evidence of gravitational differentiation involving cumulates for an Alpine type peridotite-gabbro intrusion has been obtained, in spite of modifications of the original igneous rocks imposed by regional metamorphism. Unmetamorphosed relics of cumulate rocks are a surprising feature of this occurIfence.'fhe differentiation process reflected in the layered sequences is compared to that of the Stillwater Intrusion, Montana. Phase, cryptic and rhythmic layering are recognized. The economic significance of this study lies not only in the possibility of nickel mineralization in this ophiolite belt, but also in that much detailed information on the nature of these belts, which is difficult to obtain in the case of the more altered and sheared rocks of the belts carrying gold and nickel ore deposits nearby, is gathered from the Yilmia occurrences.

Jan 1, 1969

By H. W. Earnest

This report covers the results of a two-phase study to determine the feasibility of underground disposal of retorted oil shale. Two mining methods, chamber and pillar mining and sublevel stoping, were specified for backfilling. Phase I of the study covered the evaluation of hydraulic, mechanical, and pneumatic transport and stowing systems, individually and in various combinations, and the selection of the most feasible methods. Conveyor transport and stowing and a combination conveyor transport and stowing with pneumatic topfilling were selected for detailed study of phase II. Phase II activities included detailed engineering analysis and design of the selected systems, an engineering economic analysis, and a cost comparison with total surface disposal of retorted oil shale. An extensive literature search was conducted and the bibliography is included in the report. Research done under Contract No. J0265052 by the Cleveland-Cliffs Iron Co. Available for reference at Bureau of Mines facilities in Denver, Colo., Twin Cities, Minn., Bruceton and Pittsburgh, Pa., and Spokane, Wash.; U.S. Department of Energy facilities in Carbondale, Ill., and Morgantown, W. Va.; National Mine Health and Safety Academy, Beckley, W. Va.; and National Library of Natural Resources, U.S. Department of the Interior, Washington, D.C. Order ONLY from NTIS:

Jan 1, 1978

The Waimumu area, 12 km southwest of Gore, is underlain by the Gore Lignite Measures, an early Tertiary fluvial sequence approximately 500 m thick resting on Triassic-Jurassic argillitic basement. The Waimumu Quartz Gravels (Pliocene) have been deposited locally and are in part due to the localised reworking of the Gore Lignite Measures. Structurally the area is dominated by the Dunsdale Fault System, a steeply dipping series of NE trending reverse faults (Isaac and Lindqvist, 1990). The Belle-Brook, Hedgehope and Parker Road sites sampled are adjacent to the downthrown (east) side of the Hedgehope Fault.The authigenic gold-sulphide association at Belle-Brook was discovered in 1987 (Falconer, 1987: Clough and Craw, 1989). Despite a very limited amount of alluvial mining a significant quantity of authigenic marcasite has developed. Authigenic sulphide trace element analysis has shown anomalous amounts of As, Ni, Cr and to a lesser extent Zn, Pb and eu (Table 1). It has been established that the nickel occurs as a colloform banded Ni sulphide, possibly bravoite, within the marcasite (Figures 1 & 2). Arsenic and nickel (re)mobilisation are well documented in the literature. Generally As and heavy metals are mobilised in the groundwater as a result of the oxidation of sulphides (ie as a result of mining). At Belle-Brook it is reasonable to assume the authigenic sulphide trace element composition reflects either localised groundwater contamination or hydrothermal mineralisation. This poster presents some preliminary findings.

Jan 1, 2001

By P Fullagar

Automated multi-sensor core loggers (MSCL) measure petrophysical properties of diamond drill cores, including gamma density, P-wave velocity, electrical conductivity and magnetic susceptibility. A Geotek MSCL system has been used to record petrophysical data on archival drill core from Cadia East Au-Cu porphyry deposit, New South Wales, Australia, for correlation with metallurgical parameters. P-wave modulus, calculated from density and P-wave velocity, exhibits a correlation with small-scale crushability (A*b) test results, and hence offers a means for æcontinuousÆ characterisation of ore crushability at Cadia East. Magnetic susceptibility has proved to be a good indicator of alteration styles, and is a possible indicator of crushability.

Jan 1, 2009

The uptake of nickel into the lattice of pyrrhotite, Fe1 _1J S was studied experimentally in the temperature range 200°C to 760°C. Nickel from both aqueous solutions and salt melts diffuses rapidly into the sulphidelattice with an accompanying release of iron into the solution or melt. The rate of uptake of nickel and its diffusion into the sulphide lattice were followed by optical microscopy and by analysis with an electron probe microanalyser. Some geological consequences of this phenomenon affecting the distribution of nickel in rocks associated with nickel-iron sulphide ores are discussed.

Jan 1, 1972

This report is the 26th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations and the 8th of these reports to be issued on a calendar-year basis.1 It reviews briefly work in progress during 1961, and it provides references to publications by Bureau personnel during 1961 and also to a few older papers that were not cited in prior reports of this series. Details about some of the researches mentioned may be obtained by referring to the publications cited in the footnotes or in the further list in the Bibliography; other phases of work are reported here for the first time and will be covered in more detail by later publications.

Jan 1, 1963

By L. F. Reinartz

ANOTHER year has rolled by. We are twelve months further away from the start of the depression and. therefore that much nearer to recovery. The accumulated needs and wants 'of our lame, virile population are ready to burst their bonds as soon as confidence returns and credit is stabilized. The steel industry has been harassed by uncertainty of the Government's attitude toward organized labor's de¬mands, and irregularity in volume of production. Steel labor, if left to its own devices, would in most instances, march shoulder to shoulder with the management of steel plants in their effort to pull the industry nut of the ?red.? Cooperation between management and men has improved considerably during; the year.

Jan 1, 1935

By Jorge Rodríguez Velarde

El presente trabajo describe un esquema matemático que simula un proceso de lixiviación química a partir del estudio de las variables más importantes y sus correlaciones entre sí. Para ello, se revisa los diseños experimentales, el equipo utilizado, las variables principales del sistema experimental, control de operaciones, discusión de resultados y algunas correlaciones de variables.

Nov 20, 1978

By R. Franfield

This paper describes a situation that many drilling and blasting contractors have found themselves in – a client?s fear of the use of explosives. In the summer of 2007 Blasting Services Ltd was asked to undertake some drilling and blasting work in an abandoned quarry that was being restored for a housing development. Previous quarrying operations had left a series of overhangs that were considered unsafe and required removing. The site contractor considered that the best and safest way to carry out this work was by drilling and blasting. Blasting Services Ltd, with the technical assistance of Exchem Explosives, designed a drilling and blasting regime to accomplish this work with a series of trim blasts. The design took into account the close proximity of a structure in very poor condition and the imposed vibration limit of 6.0 mm/s (0.24 i.p.s.). The faces were profiled, holes drilled and explosives ordered. A few days before the first blast was due to be carried out the client decided that the poor condition of the nearby structure meant that the use of explosives could not be permitted. This decision was made despite the blast design indicating that the vibration level would be well below the 6.0 mm/s (0.24 i.p.s.) limit.

Jan 1, 2009

By Joseph Grumer

Theory pertaining to the exchangeability of fuel gases on appliances has been extended to exchanges of propane or butane with mixtures of these. In particular, new considerations were developed bearing on the hazard of an occasional emission of carbon monoxide and flashback and blowoff possibilities. The new considerations involve using current requirements for approval of liquefied petroleum gas appliances. These requirements were used to predict allowable tolerances in chemical composition of liquefied petroleum gases for existing appliances. In addition, changes in gasline pressure were computed which may be substituted in place of fuel exchanges during testing of appliances,

Jan 1, 1962

By John McDonald, Peter C. Raleigh, Christopher Dishlip

This paper will discuss how the construction management team and the contractor working together on the City of Los Angeles, North East Interceptor Sewer project, managed information on a daily basis. Data was synthesized from various sources including: inspection, survey, instrumentation, laboratory and the tunnel boring machine data logger systems to produce state-of-the-art reports and graphics which will become industry standard. Special emphasis is placed on how the data is managed and interpreted in a clear and objective manner, permitting the tunneling processes to be carefully monitored and suggesting appropriate action to be taken by the construction management team and contractor.

Jan 1, 2005

By Yun Zhang, Haijun Jiang, Shenggen Cao, Chen Wang

The distribution of front abutment pressure is closely related to the force, deformation and energy distribution of hard roof before periodic weighting. So it is necessary to carry out research on the relationship between them. According to front abutment pressure distribution feature, using the location of peak front abutment pressure as the dividing point, coal seam is divided into two parts along the direction of mining: the yield zone that is the area between the faceline and the point where the maximum front abutment pressure occurs, and the elastic zone that is the part before the point of peak front abutment pressure. The proposed mechanical model of unit width hard roof at the panel center periodic weighting consists of five parts including the yield zone. All parameters of the deflection equations for each of the five parts that satisfy the continuity conditions and natural boundary conditions are obtained by using the Matlab software. The continuous curves of front abutment pressure, deflection, bending moment and bending strain energy density distribution of hard roof are obtained by iterative approximation method. The following conclusions can be drawn through analyzing those curves: (1) The position of peak front abutment pressure is located at the transition of coal seam foundation from yield zone to elastic zone (elastoyield critical point), the distance of it to the faceline is equal to the width of yield zone. The peak front abutment pressure increases with yield zone with. (2) The peak bending moment in front of the faceline, and the distance of it to the faceline increase with the yield zone width. The deflection of hard roof at the face and midspan also increase with yield zone width. (3) As the yield zone width increases, the accumulated elastic energy of hard roof in front of the faceline increases, and the core zone of energy moves forward away from the face. (4) When the yield zone width is zero, the whole coal foundation is regarded as elastic foundation, and the peak front abutment pressure occurs at the faceline.

Jan 1, 2015

Although these subterranean cavities are common to the Broken Hill big lode, yet the Broken Hill Proprietary is the most prolific in their occurrence, loud they have been found of various dimensions almost from the surface down to the lowest levels yet attained in that mine. Many of these vugbs have contined valuable silver, copper and lead deposits, and some have been remarkable for the beautiful forms of crystallization pendant from the roofs and walls, and collected on the floors. The question arises, How are these caverns and fissures in the ore body formed? There are numerous theories more or less feasible, but that the causes are variant is demonstrated beyond doubt. That water in its passage leaving channels, is one ofthe chief factors for their production is assured, and their presence is likewise due to the shrinkage and dropping of the earth from varions causes, to the deposition of material forming ledges overhanging, and thus leaving spaces below, and also to chemical erosion and electrical action both of which latter are constantly at work in reconstructing, segregating and dissolving tlie mineral and metallic constituents of all ore bodies.One of the most remarkable vughs yet discovered in the big mine was that opened up about three months bitek in the' heart of the ironstone body on Block 11, and located about 40 feet below the 100 feet level of Weatherley's stopes, but now destroyed in the progress of work. Probably it was caused by chemical action, the eating out, so to speak, of a soft and soluble portion of the manganic iron, leaving a,hollow about 15 feet long, with a width and height, of say, 6 feet, carpeted with beautiful zinc with a modicum of limeincrustations, apparently produced by the percolation from around the carbonate waters holding these minerals in solution. This cavern was divided into, what might be termed, a double chamber, by big boulders of manganic iron, also coated with an aggregation of small crystals of zinc and lime although the actual proportion of the latter was not determined.

By James R. Aggson

This Bureau of Mines report describes floor heave ground control problems that have been encountered in a new underground coal mine in West Virginia. Previous experience in the coal seam, the results of physical property investigations, and in situ rock stress determinations are discussed. The apparent cause of the ground control problems is the existence of a high, biaxial, horizontal stress field coupled with a floor member that has time-dependent deformation characteristics, A theoretical analysis of the failure process is developed. The analysis is assisted by finite element techniques. Mine design recommendations based on this analysis are presented.

Jan 1, 1978

By Hasan Nizamoğlu, Z. Abidin Sarı, Aslıhan Demiraslan, M. Deniz Turan, Tolga Depci

In this study, recovery of copper from solid material (obtained by leaching of chalcopyrite with oxalic acid in the presence of hydrogen peroxide) with a copper oxalate structure was carried out selectively using HCl. The chemical composition of the solid was as 29.3%, 9.7%, and 13.3% for Cu, Fe, and S, respectively. Selective recovery of copper by degrading the copper oxalate structure with a low-solubility product (Ksp = 4.43 × 10−10) was performed by conventional leaching in the presence of HCl. The optimum leaching conditions were determined as 5 M of HCl concentration, 318 K of leaching temperature, 120 min of leaching time, 25 ml/g of liquid–solid ratio and 400 rpm of stirring speed. Under these conditions, approximately 77% of copper and 3% of iron were taken into the solution. According to the characterization of the leach residue that was obtained, the oxalate structure was degraded. Moreover, the results of XRD analysis showed that the sulfur (S) and cubanite (CuFe2S3) phases were mostly observed in leaching residues, and this was supported by the SEM-EDX data. Based on the results, it may be stated that selective copper extraction can be obtained from a chalcopyrite concentrate by a two-step leaching method using a conventional hydrometallurgical technique.

By D. J. W. Piper, T. Hundert, G. Pe-Piper

"Abstract - Potentially commercial deposits of kaolin are found in the fluvial Lower Cretaceous Chaswood Formation, the sedimentologically proximal equivalent of deltaic sediments of the offshore Scotian basin. The geological setting of the kaolin deposits has been interpreted from high-resolution seismic-reflection profiles and boreholes, and mineralogical studies on one reference borehole. The kaolin is a product of early diagenesis involving meteoric water below the water table. The distribution of kaolin is controlled by the presence of intraformational unconformities that were sites of ground water recharge, and are marked by the development of oxisols above the water table. Such diagenesis was facilitated by interbedded, loosely consolidated, permeable sandstone. The highest-grade kaolin deposits are found in areas close to river belts, where overbank muds were not sufficiently drained to develop paleosols, but where later uplift created intraformational unconformities. In the sandstone, meteoric water flow altered feldspars to kaolin, thus yielding commercial silica sand deposits. It also altered ilmenite to rutile, which is concentrated as secondary placers in modern rivers that have eroded the Chaswood Formation and tills derived therefrom. Sommaire - Des dépôts de kaolin potentiellement économiques ont été notés dans la Formation de Chaswood d'’âge Crétacé Inférieur, laquelle constitue un équivalent latéral en milieu fluviatile aux sédiments deltaïques du bassin de Scotian. Le contexte géologique de ces dépôts de kaolin a été interprété a partir de profils de seismique-réflection à haute résolution, de sondages, et d’études minéralogiques sur un sondage de référence. Ce kaolin est un produit diagénétique précoce formé par de l’eau météorique sous le niveau de la nappe phréatique. La distribution du kaolin est contrôlée par la présence de zones de recharge associées à des discordances intraformationelles marquées par le développement d’oxisols au-dessus du niveau de la nappe phréatique. La présence d’interlits de grès perméables faiblement consolidés a contribué à l’efficacité de ce processus diagénétique. Les dépôts de kaolin les plus riches se trouvent en périphérie des rivières, là ou les boues de la plaine d’inondation n’étaient pas suffisamment bien drainées pour permettre le développement de paléosols, mais où des mouvements verticaux subséquents ont crée des discordances intraformationelles. La circulation d’eau météorique dans les grès a entraîné l’altération des feldspaths en kaolin, générant ainsi des dépôts économiques de sable de silice. Elle a aussi causé l’altération de l’ilménite en rutile, que l’on trouve dans des placers secondaires situés dans des rivières contemporaines qui ont érodé la Formation de Chaswood et les tills qui en sont dérivés."

Jan 1, 2006

By Murray Jacobson

A method for determining airborne trona dust concentrations using a midget impinger was developed. During sampling, the trona dust, composed of sodium carbonate and bicarbonate, dissolves in the collecting medium (water). Resulting solutions are then titrated using 0.1 [N] hydrochloric acid solution. The mass concentration of the trona sample is determined from a calibration curve relating the volume of acid required for neutralizing a collected sample to the mass of the dust. Test results obtained using this method are equivalent to those obtained using a gravimetric sampling method.

Jan 1, 1971

By Kym Runge, Emmy Manlapig

"The objective of an industrial flotation circuit is to separate valuable minerals from non-valuable minerals utilising differences in their flotation recovery rate. Regrinding and reagent addition are particle modification processes which are employed within these circuits to maximise the flotation selectivity of one mineral with respect to the others present in the ore feeding the process.Batch test nodal analysis, or the ability to compare floatability through mathematical combination of laboratory batch flotation test results, is a powerful technique for assessing the effectiveness of particle modification processes on ore floatability in industrial flotation circuits.In this paper, the use of nodal analysis is demonstrated within an industrial flotation circuit. It is used to show that regrinding and staged reagent addition within Teck Cominco’s Red Dog zinc retreatment circuit is beneficial to pulp flotation selectivity. Optimisation of these processes could potentially improve the zinc recovery within the circuit. Lime addition, which is periodically employed to depress pyrite in the circuit, was found to depress sphalerite in preference to pyrite and to result in poorer metallurgical performance in the circuit.INTRODUCTIONThe objective of an industrial flotation circuit is to separate valuable minerals from non-valuable minerals utilising differences in their flotation recovery rate.Different minerals can only be effectively separated using flotation if they are sufficiently liberated from each other (i.e. do not co-exist within the same particles) and have a sufficient difference in surface hydrophobicity. Size reduction processes and chemical addition are utilised before and within a flotation circuit to achieve sufficient particle liberation and to maximise differences in mineral hydrophobicity. In effect, the objective of these processes is to maximise the flotation selectivity of one mineral with respect to the others present in the ore feeding the process."

Jan 1, 2004