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By Walter D. Holland

LFE Environmental performed an Industrial Hygiene survey of the Paraho Oil Shale Mining and Processing facility in Anvil Points near Rifle, Colorado, on August 6 and 7, 1975. This survey consisted of an investigation of the underground operations for diesel emission contaminants and of the above ground work areas for all inhalation contaminants other than silica dust. Samples were collected to investigate the following contaminants: respirable dust, total dust, NO2, NO, H2SO4, formaldehyde, CO2, S02 and CO. None of the determinations of contaminants in the underground operations indicate air concentrations exceeding their standards. The results for the samples collected above ground indicate only one operation where the employee's exposure exceeds the standards. It is a welding operation where the standards for total dust and lead are exceeded. Since the survey the employer has installed an exhaust ventilation system which has significantly reduced the welder's exposure.

Jan 1, 1976

By Chase E. Sutton

The porosity of a sand is usually the measure of its capacity for holding fluid, although porosity is sometimes selective; that is, a small percentage of the actual pore space (voids), particularly in fine-grained sandstones, may be isolated by the cementing material which prevents the entrance of fluids under normal conditions. Obviously, however, porosity determinations are essential to an engineering study of underground conditions of an oil field, and a simple and reliable method of obtaining a reasonably accurate figure for average porosity is desirable. This report describes a method suggested by Ruasell,3 which was used by the writer in the preparation of a report on the Texhoma-Gose pool, Archer County, Tex.4 The conditions in this pool were particularly favorable for obtaining an average porosity figure, in that some 30 to 35 core samples of the pay sand were available for analysis.

Jan 1, 1928

By M. Jahazi, J. Gholipour

Design and manufacturing of parts using hydroforming process require knowledge about material behaviour and tribological effects during hydroforming. Lubrication is one of the key issues in successfully hydroform the tubes. A Ni-based super alloy tube with 50.8 mm (2 inches) outer diameter and 0.9 mm (0.035 inches) thickness is considered for this research to study the effect of lubricants on the formability of the tubes. Hydroforming of a hollow compressor blade is considered for this project. A combination of press forming and hydroforming is employed to produce the part. LS-DYNA, an explicit dynamic finite element code, is used to model the experiments. Different lubricants are modeled using different coefficient of friction in the model. Predicted results for strain distribution at a critical section of the tube are extracted for each case to evaluate the effect of different lubricants on the process.

Jan 1, 2006

By Raj P. Singh

Lewatit TP207, a chelating resin with iminodiacetate functional group, is used for the purification of cobalt hexammine chloride solution for divalent cationic impurities (US Patent No. 5,154,757). The method is employed at commercial scale in OSRAM SYLVANIA Inc. cobalt chemical production since 1992. It is observed that after long use in the purification of cobalt hexammine chloride solution, a large number of resin beads tum black from their original beige color. The purpose of this paper was to characterize these black-colored resin beads for their ion exchange behavior. The resin sample used in this work was an exhausted production TP207 resin containing large number of black-colored beads. The results indicated that blackened resin beads can be regenerated to almost full capacity and' their ion exchange behavior for the purification of cobalt hexammine chloride solution was comparable to the new resin.

Jan 1, 2001

By W. G. Jewitt

YELLOWKNIFE, the most northerly Canadian gold mining district, is once more in the throes of a boom. Touched off by spectacular and well-publicized diamond-drilling results on the property of Giant Yellowknife Gold Mines, Ltd., mining companies and the general public are competing for mining claims and for the shares of companies owning mining claims in the area, with little regard for values. Such a stock-market boom has various unfortunate consequences but undoubtedly one beneficial result is that considerable amounts of money are made available for serious development. The Yellowknife mining area lies on the north shore of Great Slave Lake, in the Northwest Territories, at a latitude of approximately 62°30' north. The topography is a low-relief phase of that usual in the Canadian Laurentian shield. Roughly, one third of the surface is lake-covered, one third muskeg or overburden, and one third is bare

Jan 1, 1944

By Michael D. Dunn

The Bureau of Mines evaluated a quartz schist formation within the Blue Joint Wilderness Study Area which was identified as having a "high potential" for copper-silver-cobalt-barium resources. Stratiform and remobilized copper occurs near, and bedded barite within, the study area. In addition, the black to gray Proterozoic quartz schist may correlate with the Yellowjacket Formation which contains cobalt-copper-gold-silver deposits at Blackbird, ID, about 30 miles to the south. Eighty soil and 43 rock samples collected across the quartz schist formation were analyzed for gold, silver, copper, cobalt, and barium. During the reconnaissance and sampling, particular attention was given to looking for malachite (copper carbonate) and erythrite (cobalt arsenate, also known as "cobalt bloom"). The sample analyses and geology in this localized area do not provide enough evidence to support the "high potential" designation for copper-silver-cobalt resources. Barium potential still appears high, however.

Jan 1, 1987

By J. R. Hurley

The continuous flow, horizontal drum blender has dynamic properties which may be described by the same type of equations which often arise in electrical filter analysis. Furthermore, the equations may be readily solved by the same techniques used in electrical control analysis. For this reason the blender model developed is termed an "Electric Analog", although strictly speaking it is a mathematical model. Presentation of the dynamic performance of the blender as an electrical (or mathematical) model is desirable for several reasons. The model can be of assistance in correlating performance data with equipment design parameters. The model 'can be used with other process equipment models for simulation of an entire plant operation or in stability studies. In addition, the model may be useful in providing insight into the actual blending mechanism, or it may suggest a similar method of analysis for other closely allied equipment.

Jan 1, 1967

By Graham W. Marks, Clyde A. Bridger

"INTRODUCTION An electrolytic process for the preparation of metallic cobalt has been developed recently in the Bureau of Mines Experimental Station at Boulder City, Nev. Chemical analysis shows this cobalt to contain impurities in small percentages, chief of which is nickel. It is desirable to be able to determine these impurities spectrographically. This report is concerned with a procedure for the spectrochemical determination of nickel in cobalt.Previous spectrographic work on cobalt was done by Breckpot and Mevis,/ who used the method of homologous pairs of lines. However, it was felt that a more detailed investigation was needed, employing the method of internal standards.ACKNOWLEDGMENTWe are indebted to B. G. Knickerbockor and his staff at the Boulder City, Nev., station of the Federal Bureau of Mines for their cooperation, and particularly to Richard W. Lewis and Robert G. Sanderson, who prepared nickel-free electrolytic cobalt for us."

Feb 1, 1948

By S. L. Barua

An industrial engineering and computer simulation study was conducted on reclamation operations to evaluate the possibility of integrating mining and reclamation operations, and to evaluate the factors which influence the production potential of scrapers. The study was done in a southern Illinois strip coal mine producing approximately 2.27 M metric tons (2.5 million short tons) of clean coal annually. The main outcomes of this study are (a) it is possible to reduce reclamation cost about 20-25 percent by integrating reclamation and mining operations, (b) haul distance has the most significant effect on scraper production, (c) push-pull is the best mode of operation for wheel scrapers for topsoil/subsoil removal, and (d) historical data obtained from the mine for one year show that average dozer productivity in rock grading is about 60 percent lower than the expected production; similar data for scraper is about 25 percent less.

Jan 1, 1981

By M. W. Grabinsky, P. B. Tomory, J. Carvalho, J. H. Curran

Many underground mining operations use Split Set friction stabilizer bolts for rock support. Currently, however, little has been done to quantify the effects of various rock mechanics and operational parameters on the capacity of frictional support systems. The strength of Split Sets is usually measured by means of a pull test wherein a jacking force is applied to the bolt and a slip load is obtained. In order to evolve a rational design procedure for this type of support, an extensive database of over 900 pull test results from more than 50 mines through- out North America has been assembled and analyzed. Associated relevant rock mechanics parameters (rock type and quality) and operational details (drilling method, bit size, drive time, time to pull test) were also obtained, as completely as possible, for each test. Analysis of the information has yielded several charts that relate pull-out strength to relevant parameters and simple statistical analyses were conducted where necessary. Quantified distributions for pull-out strength were also produced for several operating conditions. The factors that most significantly affect bolt strength have been identified and specific applications to design are discussed. The information presented will assist mining engineers in designing safer and more economic support using Split Sets.

Jan 1, 1998

By Jae-Ho. Lee

Mercury is a toxic contaminant encountered in the extraction of gold from mercury-containing ores. It is found in the leach solution of CIP circuits and in the cathodes of the electrolyte cells used to electrodeposit the gold. The research conducted has examined the potential for selective removal of mercury from synthetic Au-Hg-CN electrolytes containing only gold, only mercury, and both gold and mercury. Cyclic voltammograms were obtained for mercury- coated copper electrodes with these cyanide electrolytes. Exchange current densities were determined from the voltammograms in the low overpotential region. Laboratory scale batch- electrolysis at constant current was also conducted for the electrolytes containing only mercury and both mercury and gold, at 20 and 50°C and from which the kinetic behavior associated with the process was analyzed. The surface of cathode before and after electrolysis was also characterized and a copper mercury intermetallic (CyHg,) was identified. Gold codeposited with mercury during the later stages of electrolysis. The results of this work corroborate that the mercury-amalgam copper electrode offers a viable electrochemical technique for the selective removal of mercury, however a high-surface-area cathode-cell would have to be utilized to provide for the desired selectivity.

Jan 1, 1994

By N. A. Gokcen

In this Bureau of Mines report, appropriate equations correlating the activity of water with the activities of electrolytes in binary and multicomponent solutions have been derived for computer calculation. It was found that the half-integer power series are far superior to the integer power series, for both types of series having the same number of terms. The pro-posed method of calculation is capable of accurately yielding the activities of all components from the measurements of the activity of a single component at various concentrations. This method replaces the cumbersome and objection-able method of graphical integration of the Gibbs-Duhem equation. Two novel methods are proposed for determination of activities of electrolyte solutions important in hydrometallurgy; (1) Water vapor pressure measurement by differential pressure transducers having an accuracy of 0.001 pet, and (2) transpiration method with an inert gas bubbled through concentrated solutions followed by the analysis of the evaporated and redissolved electrolytes with specific ion electrodes having a sensitivity of ±10-10 molal. The first method is suitable for nonvolatile electrolytes, and the second, for volatile electrolytes such as hydrogen halides, HN03, H2S03, etc. The existing methods of estimation of ionic activities have been surveyed, and the best method has been selected, discussed, and summarized.

Jan 1, 1979

By C. J. Sullivan

"The outlook for supplying the world's metal needs in the next twenty-five years is good, although in several cases basic costs are likely to increase with rising demand. Metal prices calculated at a constant dollar from 1900 to the present show that for nickel, copper, silver, lead, zinc and tin, prices -and presumably production costs -fell from 1900 to the early 1930s. Since then, they have generally risen, apparently reflecting some depletion in relation to demand. This tendency has been accentuated since the post-World War II adoption of managed, full-employment, growth economics, which have resulted in a sharp escalation in world demand for metals. (Abandonment of such policies, apparently now under consideration in North America, would, of course, affect the pre-dictions of this paper.) Nevertheless, metal prices generally are still below those prevailing in 1900. Exploration potential exists for disseminated ores of many metals still thought of as characteristic of lode and vein deposits. These include uranium, silver, gold, tin and nickel and, to a lesser extent, lead and zinc. Considering the discovery potential for some principal metals in relation to expected demand and prices, I would tend to rate them as follows: molybdenum, zinc, lead, uranium, silver, gold, tin, nickel and copper."

Jan 1, 1970

By B. Zilbergleyt

Current understanding of chemical equilibrium is based exclusively on the probabilistic considerations that are correct for isolated systems with only one chemical reaction to take place. For the systems with multiple chemical interactions, current paradigm of chemical thermodynamics promotes the idea of openness, artificially flavored with coefficients of thermodynamic activity. Recently introduced thermodynamics of chemical systems and the Method of Chemical Dynamics (MCD) offer explicit accounting for the multiple chemical interactions within the system. In the new theory, thermodynamic equilibrium of the j-subsystem obeys the logistic equation derived exclusively from the currently recognized concepts of thermodynamics. Having the only one new parameter -the subsystem's reduced chaotic temperature 'tj to describe external interactions, and reaction extent Ilj as independent variable, this equation covers the whole domain of the system's possible states from true thermodynamic equilibrium through the open equilibrium to bifurcations and chaos depending on the 'tj value. The MCD brings new opportunities to thermodynamic simulation of complex metallurgical and chemical systems, allowing for the analysis of their domains of states and the area limits, and for more accurate calculation of the equilibrium compositions. Its usage is exemplified in this paper by several applications. Keywords: chemical thermodynamics, open systems. complex systems, chemical dynamics.

Jan 1, 2003

By K. Dagdelen , S. K. A. Owusu

Uncertainty with regard to estimated grades and tonnages of a mineral deposit demands risk assessment in order to build investor confidence and attract the interest of other stakeholders in the success of a project. Uncertainties associated with Mineral Resource estimates can lead to unreliable production schedules and unpredictable cash flows. However, the techniques used in the mining industry to determine these uncertainties are inconsistent, because the important decisions taken in the process are solely dependent on the responsible Competent Person (CP), without limitations. This leads to disparities between different CPs’ results, using data-sets from the same drill-holes. The various standard codes for public disclosure provide guidelines and recommendations for the classification of Mineral Resources and Reserves but do not provide details on, for example, the amount of geological and geostatistical information needed to qualify for each category of Resources and Reserves. The parameters used to generate the classification categories are subjectively assumed by the responsible CP. In this paper we investigate the impacts of different CPs’ judgements on resource classification, using the same data-sets. The results underpin the need for the mining industry to develop a uniform Mineral Resources and Reserves classification framework that can minimize or avoid significant discrepancies that lead to potential misleading public disclosures.

Aug 8, 2024

By Gabriela Pino, Maurício Torem, Diego Veneu

Because of its simplicity, economy and biocompatibility, research regarding the use of microorganism for decontaminating heavy metals produced by many industries is an area of growing interest. Also, there is a stringent need for the control of toxic metals produced during various production processes and released into the aqueous environment in order to avoid damage relevant to soil or groundwater contamination. Among the available treatment technologies, sorptive flotation has been considered as a promising alternative for the wastewater treatment. In the present study Streptomyces lunalinharesii strain was applied as bioreagent for the removal of copper, cadmium and zinc. The removal of those metal ions depends mainly on the respective pH value, influencing the aquatic speciation during the process, as well as the zeta potential of the system and biomass concentration. Langmuir and Freundlich isotherms have been depicted. Dispersed air flotation was applied as the subsequent separation method for harvesting the suspended metal laden microorganisms, following the biosorption of copper, zinc and cadmium. The investigated parameters (in batch mode, laboratory scale) were in this case the saturator pressure, the coagulant concentration and the recycled flow. Applying the optimum defined conditions, over 60% removal of metal ions have been achieved in one stage and simultaneously, quantitative separation of the used (metal-loaded) biomass has been obtained.

Jan 1, 2014

By P. Jonsén

Understanding mill charge motion is important. In the charge, the centre of gravity is shifted from the rotational centre of the mill system, and its motion is induced by rotation of the mill, while at the same time the charge creates a torque into the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to the motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty to measure in a tumbling mill. Experimental measurements in a lab mill were done for diverse load cases: varying feed materials, mill fillings, mill speeds and pulp liquids. The mill is set up to directly measure the charge-induced torque. The accuracy is good with relative uncertainty smaller than ±2% for relevant load cases. A full three dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill start-up behavior for torque and mill power. This proves that the model is physically correct, and can be used for full-scale mills.

Feb 27, 2013

By V. Pouyafar

In recent years semi-solid processing of steel alloys has gain more attention among researchers. Production of high quality complex steel parts with higher mechanical properties is the final goal for all these researches. A thorough understanding of the flow behavior of the metal under investigation is the key for a successful process design. The material used in this research is M2 tool steel. The experiments were performed using a Searl-type concentric cylindrical rheometer which is specially designed for high temperature rheological measurements up to 1500 ºC. The rheological techniques were consisted of continuous cooling experiments and isothermal holding and also shear rate step change experiments for different solid fractions. Based on the rheological data a single phase thixotropic model has been derived and adopted to the measured data. The state of the microstructure has been applied through a structural parameter. The model fits well with the experiments.

Oct 1, 2011

By S. Veeramasuneni

The sign of the surface charge for alkali halides in their saturated brines has been established from non equilibrium electrophoresis measurements and on this basis the flotation response of alkali halides was explained based on the adsorption of oppositely charged collector colloids by heterocoagulation. These surface charge results for alkali halides are generally as expected from simplified lattice ion hydration theory with some exceptions, specifically LiF, KCI, NaCl, KBr, RbBr, KI, and Rbl .The presence of natural oxygen defect states in the crystal lattice and the inaccuracies involved in the gaseous ion hydration free energy values used appear, in past, to be responsible for these deviations. The presence of natural oxygen defect states in KCI, KBr, RbBr, and Rbl as characterized by UV Nis absorption, was found to account for their anomalous surface charge. Further, other positively charged alkali halides, LiF, NaCl and KI, were found to be free of oxygen defect states. Nevertheless, oxygen defects can be created in these alkali halides to make them negatively charged and has been demonstrated for NaCl. Such negatively charged NaCl can be readily floated with positively charged amine collector colloids thus confirming the surface charge/collector colloid adsorption theory.

Jan 1, 1996

By Abdulazeez Rotimi, Barry Sheppard, Abid Adekunte

Good engineering practice is a function of sound theoretical knowledge, first-hand experience on previous projects of similar scope and scale, good acquaintance with case histories of similar projects completed by others in similar environmental conditions, as well as satisfactory degree of exposure to state-of-the-art methodologies. The four factors itemised above are typically interdependent. They amalgamatively influence the judgement of the Engineer and they ultimately result in the delivery of safe and cost-effective solutions by Professional Engineers. This technical paper presents detailed information on the ground engineering aspects of a large-scale housing development project located on a sloping site that had been presumed to be unstable in West Sussex, England. The ground engineering design package for the scheme comprised of temporary working platform designs & stability assessment for piling rigs and other construction machinery, geostructural designs for approximately 1km total run of permanent bored pile retaining walls to support the split-level construction on the sloping site and geostructural designs for the permanent foundation piles to support the housing units. The paper details how the four factors outlined above were amalgamated by the project’s foundation specialist consultants & piling contractors to deliver safe and practical solutions for the development, with significant savings in materials, cost and project completion time.

Sep 8, 2021