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By M. J. Adam

As part of its research programs, the Bureau of Mines is investigating the partitioning of complex sulfide minerals to simpler sulfide phases by sulfidation reactions. Partitioning in this manner can afford opportunity to improve selective extraction of mineral constituents of value. This report describes research involving the sulfidation partitioning of the mineral pentlandite, which is an important source of Ni in primary production. For the laboratory studies, the pentlandite was synthesized in nominally equiatomic proportions of Ni and Fe. Elemental Ni, Fe, and S powders were blended, compacted, and sealed under reduced He pressure in vitreous silica tubes. The tubes were heated under controlled conditions at SOD? C for 24 h. The product was verified by X-ray diffraction and chemical analysis to consist essentially of (Ni,Fe)9S8. Small samples of the (Ni,Fe) S were encapsulated with sulfur in silica tubes at reduced He pressures and heated for 1 to 24 h at specific temperatures between 400? and 600? C, both below and above the boiling point of sulfur (_445° Cl. Reaction rate increased with temperature. Within this temperature range, partitioning to individual Ni and Fe disu1fides proceeded to essential completion according to the reaction

Jan 1, 1988

The ultraviolet spectrum of isopropyl ethylthionocarbamate (the principal constituent of Dow flotation collector Z-200) in water and of Z-200 itself in water was found to have an absorption peak at 242 nanometers(nm). The height of this peak was found to be directly proportional to isopropyl ethylthionocarbamate concentrations up to 15 p.p.m. Z-200 contains about 90 per cent isopropyl ethylthionocarbamate and the heightof the peak was proportionately lower, but obeyed the straight line relationship up to 15 p.p.m. This showed the potential value of spectrophotometric measurements for the determination of Z-200 residuals in flotation liquors.Methyl ethyldithiocarbamate (an impurity in Z-200) increased the peak height slightly, but other impurities in Z-200, xanthates, and most inorganic salts present in flotation liquors do not interfere. However nitrate ion and thiosulphate ion have absorption peaks which overlap the isopropyl ethylthionocarbamate peak.The simplest general method to overcome this effect is to extract the isopropyl ethylthionocarbamate into cyclohexane and to measure the absorbance of the extract.The maximum absorbance of the cydohexane extract was at 247 nm and the peak height at this wavelength was found to be directly proportional to the isopropyl ethylthionocarbamate or Z-200 concentration in the original aqueous solution. An alternative method is to measure the spectrum of the original aqueous solution using the aqueous raffinate from extraction as a reference solution. This gives the spectrum due to isopropyl ethylthionocarbamate alone and measurement of the absorbance at 242 nm gives the concentration in the original aqueous solution. Both methods give the same value for the concentration of isopropyl ethylthionocarbamate in the original solution.

Jan 1, 1969

Optical sensors have emerged during the telecom boom in the late 1900s, due to the availability to low-cost telecom-grade optical components. It's only after the telecom industry's fall in 2004 that optical sensors became sufficiently developed to be a viable technology for real-world applications. Geotechnical applications have long relied on electrical sensors such as thermocouples, strain, and the venerable vibrating wire to measure physical phenomena. Although these are well suited for a large variety of applications, electrical sensors cannot be used for all applications: these are vulnerable to noise, hazardous voltages and corrosion, limiting the environments in which they can be used. In addition, electrical wires can also become an issue when sensors require external excitation or are distant from the measurement system. Finally, changes in physical properties of electrical sensors and systems over time makes regular calibration a necessity - not easy to do when these are permanently mounted on structures. Optical sensing systems are non-conducting and use light to perform various measurements. There are several optical sensor technologies available, each with different strengths and weaknesses. In addition, there are different methods of interrogating optical sensors, each of which also present different strengths and weaknesses. To make matters worse, configuring the interrogation and scaling to physical units can also be challenging to the unprepared engineer. This paper will present a holistic view of optical sensing, presenting the different optical sensor technologies and interrogation techniques. Sample optical sensing systems will be revealed and top considerations for optical sensing will be presented.

Nov 25, 2010

By A. Steinmüller

Introduction In the design and operation of gravity concentration circuits, the application of process models for spiral concentrators offers significant benefits. A substantial amount of work has been produced over the last 30 years in the field of modeling the metallurgical performance of spiral concentrators. It is not the aim of this contribution to add to the refinement of modeling technique but to share some of the experiences and potential improvements which can be achieved in a relatively simple way. The design of spiral circuits usually requires extensive testing. This is often conducted in batch operation only, either due to lack of suitable continuous testing facilities, the unavailability of sufficient quantities of sample, or other constraints. Typical problems arising during circuit development from batch testwork are the extrapolation of results to different feed conditions, and resolving of internal recycles. Model selection and development The classic approaches in spiral modeling technique range from fundamental fluid dynamics, based on the Navier-Stokes equations in combination with expressions for local slurry properties, to fully empirical and statistical models. With the initial objective of developing an in-house tool for gravity circuit optimization and development, mathematical model types from each category, available either commercially or in the published literature, were evaluated. Model selection For the desired purpose, an approach proposed by Holland-Batt (1990) was found suitable, which was adopted and modified. Holland-Batt reported that the shape of release curves in spiral applications could be described by a combination of a linear function in the initial recovery zone, and a power law function outside this zone. The proposed recovery function was formulated as

Jan 1, 2005

By Steven R. McCutcheon

ABSTRACT - The Bathurst-Newcastle district, a subcircular area approximately 50 km in diameter, contains 37 massive-sulfide Zn-Pb-Cu deposits that have defined tonnages, and has 58 additional significant occurrences. The largest deposit is Brunswick No . 12, with total reserves (including past production) of 148 million tonnes grading about 12.50% combined Pb-Zn. The deposits/ occurrences are spatially associated with a felsic volcanic pile that contains a significant sedimentary component. In the vicinity of the Brunswick deposits the pile is divisible into lower and upper sequences. The lower is characterized by megacrystic rhyolite (QFAS) and coarse- to fine-grained quartz ( ± feldspar) wackes and/or tuffites (QAS); the upper sequence is characterized by aphyric to sparsely porphyritic rhyolites (HWR), micro-breccias, and acid hyaloclastites with interbedded dark gray sedimentary rocks. A greenish gray to dark gray siltstone (GGS) separates the two sequences and hosts the sulfide deposits. Lithogeochemistry of !east altered samples shows that the QFAS and HWR have an igneous character, whereas the QAS and GGS have a sedimentary sig­ nature. The two types can be distinguished on the basis of total alkalies (Na2O + K2O) versus SiO2/Al2O3, and Ti02 versus Fe/(Fe+ Mg). Some trace elements, such as Sr and Y, also help differentiate the two types. The QFAS differs from HWR by having higher La/Yb ratios but lower Zr and Th. The Bathurst deposits do not show a close spatial association with rhyolites but rather are stratiform bodies (lacking clastic textures) within fine-grained sedimentary rocks. The scarcity of barite and other sulfates indicates that there was little mixing between the metal­ bearing fluids and cold seawater. High Fe/(Fe+ Mg) ratios in chlorites also indicate the fluids did not contain a significant seawater component. These features and the large size of many deposits suggest that the deposits formed from metal-rich pore waters that were released catastrophically from an acquifer in the footwall stratigraphy.

Jan 1, 1992

By Frank G. Horino

Drill cores from 18 exploratory holes that were drilled into the unleached saline beds were tested for mechanical properties by the Bureau of Mines. Test cores were primarily selected from zones L4B, R4B, L3, and R3A in the Piceance Creek Basin, Rio Blanco County, Colo. Regression analysis techniques were tried in an attempt to relate kerogen yield or apparent specific gravity to the parameters compressive strength, Young's modulus, and Poisson's ratio. Correlation coefficients were very poor, indicating that this type of analysis was not amenable to these data. Analysis of variance techniques were tried using a division of either greater than or less than 10% nahcolite together with the requirement of less than 3% dawsonite. Results showed that a larger percentage of nahcolite tended to lower the compressive strength and to increase Young's modulus. A second analysis was made using a division of less than 3% dawsonite and greater than 3% dawsonite together with the requirement of less than 1% nahcolite. For this analysis, a larger per-centage of dawsonite tended to increase compressive strength, Young's modulus, and Poisson's ratio. Mean compressive strength values were determined for the mining horizons of interest. Average physical properties for design purposes were also determined for the horizons of interest and for a proposed adit based only on logged geologic depths to these horizons. No consideration was given to percentages of nahcolite and dawsonite. Creep data obtained from nahcolite-and dawsonite-rich oil shales provides a best fit to a modified power equation.

Jan 1, 1978

By Kenneth Eilerts

[The development and operation of ?combination on wells?5/ have created new and unusual problems, many of which cast to solved only if information is available concerning the properties of the fluids produced. Data as to the characteristics of the fluids at the relatively high pressures that exist in the reservoirs are especially important, and there is growing economic concern to know what part, if any, of the liquid recovered at the surface was liquid in the reservoir, As an extension of this problem, it is important to Know whether liquid will be formed in the reservoir it as a result o a isothermal retrograde condensation when the reservoir pressure is reduced. The pressure range of such condensation, if it occurs, is significant in the design of gas-recycling plants for maintaining reservoir pressures. In connection with the operation of such plants, it is particularly important to know how gyres sure and temperature will affect the yield of the liquid phase and the composition of the gas to be returned to the reservoir. It has not been possible to predict the behavior of these fluids that have high ratios of gas to liquid by comparing them with the behavior of low gas-liquid ratio fluids at identical pressures and temperatures. Such comparison fails because the proportions in which a component will be distributed between the phases of a system at any given temperature and pressure depend increasingly on the composition of the mixture as the critical temperature and pressure of the oysters are approached. Because many combination wells are producing from reservoirs that have temperatures near the critical point, experimental date on the properties of the fluids under reservoir conditions are particularly important at this time. To rest the immediate requirements of the industry for such experimental information an equilibrium cell has been constructed at the Petroleum Experiment Station of the Bureau of Mines, Bartlesville, Okla. When adequate experimental date, have boon accumulated, it may be possible to mare dependable estimates of the phase relations ft. high gas-liquid ratio fluids at the pre runes and temperatures characteristics of ?combination-well? reservoirs.]

Jan 1, 1940

By Raffaella Granata

The paper deals with the remediation of two areas formerly utilized for the disposal of hazardous wastes in a petrochemical plant. The works, designed on the basis of the criteria of maximum safety and minimum environmental impact, consisted in the confinement of the contaminated soil and groundwater within surface caps and perimetrical cut-off walls embedded in the underlying clay layer. The cut-off wall is 0.8 m thick and has a maximum depth of 33 m: it was designed to guarantee, as a minimum, the level of safety for a landfill for hazardous wastes, in accordance with the applicable National Standards. It was constructed with self-hardening mud and with the installation of an HDPE geomembrane. The HDPE liner of the cut-off wall was then sealed to that of the capping to obtain the complete encapsulation of the contaminated soil. A system of piezometers allows the monitoring of the cut-off efficiency measuring the fluctuations of the groundwater table and testing the chemical contents. Some wells installed within the contaminated areas will contribute to guarantee the full efficiency of the system in case of state of emergency, controlling the water-table level inside the confined areas.

Jan 1, 2006

By Rudolph P. Frizzi

Quality control is essential for augered cast-in-place (ACIP) piles (also known as continuous flight auger (CFA) piles outside the United States) and drilled displacement (DD) piles since the pile is constructed below the ground surface out of the direct sight of the personnel constructing and inspecting the pile. ACIP piles are being successfully constructed to support high-rise structures, hospitals, arenas and stadiums, mass transit systems, and power and industrial facilities. The use of DD pile technology is also gaining ground in the United States, typically utilizing proprietary systems such as Omega (currently utilized by Richard Goettle Inc., and LG Barcus and Sons, Inc.), Berkel, and DeWal (currently utilized by Morris-Shea). Different types of ACIP/DD pile installation equipment are shown in Figures 1 and 2. ACIP piles are installed into granular and cohesive soils, and soft rock to lengths currently approaching 130 ft (39.5 m), with diameters up to 24 to 36 inches (610 to 915 mm), and sustaining design loads approaching 900 kips (4000 kN). Current DD pile installation equipment in the United States is capable of installing up to 79-ft-long (24 m) piles with diameters ranging from 12 to 18 inches (305 mm to 460 mm).

Jan 1, 2004

By Roderick Eggert, Dipesh Dipu

We look at the empirical evidence of coal block auctions in India to understand how competitive intensity affects the bid amounts in common value auctions. The results suggest that competitive intensity measured through the number of bidders for a coal block is instrumental in determining the bidding outcomes. The presence of higher numbers of bidders in the auction leads to higher bids - every additional bidder causes the bid amount to rise by INR 142.67 per tonne of coal for auctions studied for 127 coal blocks from 2014 to 2023. The paper also examines the moderating and mediating effect of competition on bids and on excess of bids from the comparative market price of coal from alternative source of Coal India Limited. The results indicate that competitive intensity does not have statistically significant impact on the relationship between common value of coal blocks and bids, neither as a moderator nor as a mediator. The strategic behavior of the bidders has also been observed as bidders have been seen to bid in a higher than market price in order to outbid the competitors.

Feb 1, 2025

By Vincent Castranova, Jane Y. C. Ma, Joseph K. H. Ma, Chang-geng Mo, Carl J. Malanga

"A group of bisbenzylisoouinoline alkaloids has been shown to exhibit various degrees of effectiveness in preventing silica-induced fibrosis in animal models [1, 2]. The objective the present study was to characterize the binding of several of these alkaloids to phosphatidylcholine vesicles and rat alveolar macrophages using fluorometric and equilibrium dialysis methods, respectively. The lipid binding affinity of these alkaloids was found to depend upon several structural factors including hydrophobic substitutions, chiral configurations, and double oxygen bridge-restricted conformation of the benzylisoquinoline moieties. Tetrandrine, which is a highly effective agent in preventing fibrosis, showed strong binding to both lipid vesicles and alveolar macrophages. In contrast, certain analogues of tetrandrine such as curine and tubocurine, which have little or no effect on silicosis, exhibited only weak binding to lipid vesicles and almost no binding to cells. The moderate binding affinity of fangchinoline to vesicles and cells corresponded to a moderate effectiveness of the compound as an antifibrogenic agent. Methoxyadiantifoline, an alkaloid of unknown antifibrogenic potential, also exhibited high binding affinities for lipid and cells. In conclusion, the results of these studies indicate that alveolar macrophages exhibit large binding capacities for certain members of this class of bisbenzylisoquinoline alkaloids. A positive correlation was observed between binding affinity to alveolar macrophages and the reported antifibrotic potency of these compounds. These data also suggest that the ability of these drugs to interact with alveolar macrophages may be a key step in inhibition of the progression of silica-induced pulmonary disease.INTRODUCTIONInhalation of crystalline silica is associated with the development of silicosis. This fibrotic disease is characterized by the appearance of concentric hyalinized nodular lesions in the lungs with the progressive development of pulmonary dysfunction [3, 4]. Many theories concerning the etiology of silicosis involve silica-induced activation of alveolar macrophages. Evidence indicates that in vitro silica exposures result in the generation of chemiluminescence, and the release of superoxide and hydrogen peroxide from alveolar macrophages [5]. Activation of alveolar macrophages has also been demonstrated after intratracheal instillation or inhalation of silica [5, 6]. Such excess release of reactive products from pulmonary phagocytes has been associated with damage to the lung parenchyma [7, 8]. In addition, silica exposure results in the release of mediators from alveolar macrophages, which enhance proliferation of fibroblasts and collagen synthesis by these pneumocytes [9-12]."

Mar 1, 1992

By Michael Allen, Paul Worsey

In underground blasting, the pull of the initial cut is the limiting factor for the success of the rest of the round. By improving the pull of the first cut, a critical step is made towards improving the entire round. This project attempted to optimize a burn cut’s effective pull by varying the depths of the relief holes in the burn. The effect of varying the depths of the relief holes was investigated, including depths longer than that of the cut’s charged holes. The overall objective was to consistently achieve greater pull than in a standard burn, using an identical amount of explosives. Increased pull results in savings of both time and cost in underground heading advance.

Jan 1, 2015

By G. Danko, R. Tiwari, J. Knowles

Many excavation and loading tasks require equipment operators to simultaneously coordinate the motion of multiple machine links, in order to achieve complex tool trajectories. Efficiency, ore selectivity, and machine wear, are all affected by the skill level and attentiveness of the operator. A software-based kinematics reconfiguration system designed to assist operators with various tasks has been implemented on a small experimental excavator using our new differential control architecture. Kinematics transformation and feedback control algorithms are being developed and tested using computer simulation, and the results implemented on the experimental excavator. Several task-specific kinematics transformations, including a virtual revolute-to-Cartesian machine reconfiguration and computer-assisted bucket steering and stabilization have been successfully tested. Progress, challenges, results, expected benefits, and planned work are described.

Jan 1, 2006

VOLUME III The objective of Volume III of this report is to provide a concise review of six major types of legal constraints, controls, and regulations on surface coal mining in the United States, as of January, 1976. At the same time, an attempt is made to format the details of federal and state exploration, mining, and reclamation regulations such that point-by-point comparisons can be made and updated as revisions occur. Thus, Volume III should provide both an executive overview and a user's manual of legal controls of surface coal mining.

Jan 1, 1976

By Russell J. Miller

A high-pressure intensifier system was designed, constructed and field tested as part of a program to determining the feasibility of applying high-pressure water jets on conventional mechanical rock excavation equipment to increase advance rates. Also developed were a high-volume swivel, capable of transferring the high-pressure water to a rotating cutterhead and manifold system for locating and protecting the jets on the cutterhead. Field tests were conducted in a granite quarry near Skykomish, WA, approximately 90 miles east of Seattle. The concept of improving excavation rates by using water jets to assist mechanical cutting was proven to be successful, with an average increase in excavation mete of 50 to 60%. For some tests, the excavation rate was more than doubled. Machine torque requirements were reduced approximately 25% when the water jets were used. It was suggested this was due to reduced cutterhead friction in the presence of the water jets. A comprehensive economic analysis was undertaken as part of a concurrent study to determine the degree of cost benefits attainable from increased advance rates. Very significant savings were seen to be possible. It was concluded that the basic concept of combining a water jet capability with a mechanical excavating machine is definitely possible.

Jan 1, 1976

By G. H. Glos

There was a time when an occasional failure of a tailings embankment was considered an acceptable risk associated with mining activities. This is not the case anymore. A major tailings failure today could result in the indictment of mine officials, huge fines and a possible site closure due to the loss of operating permits. As a result of this changed operational environment, tailings disposal facilities must be operated with these potential consequences in mind. Physical controls for tailings embankments are prohibitively expensive. However, the nuclear industry has developed a system of administrative controls as an alternative to physical controls. Administrative controls may be defined as control of actions, through organizations and management, using written procedures, record keeping, review and audit to assure operation of a facility in a safe manner (10 CFR 50). Administrative controls can reduce the cost of operating tailings impoundments, as well as increase the level of confidence in these facilities.

Jan 1, 1999

By James J. Scott

Research and development has been carried out on the patented Dynamic Rock Anchor, tradenamed DYNA-ROK and DYNA-ROK PLUS Anchors, which are manufactured and marketed by Ingersoll-Rand Company. This paper will present the results of field testing of this revolutionary new concept in ground control. Geologic conditions will be described where the plastic sleeve of the DYWA-ROK anchor alone is sufficient to provide anchorage and also, where in softer ground conditions, the DYWA-ROK PLUS is applied. The rationale for making the decision as to the type of fixture to be employed, the length of plastic tube to be used and the quantity of resin are explained. Pull test data will be shown from eight different coal seams in the Eastern United States where the product has been installed.

Jan 1, 1990

By Zhongning Shi, Ramana G. Reddy, Min Li, Zhaowen Wang

Electrodeposition of cobalt from cobalt tetrafluoroborate (Co(BF4)2) was investigated using 1- butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) ionic liquid. The experiments were conducted at 353 K. Chronoamperometry experiments confirm that the electrodeposition of cobalt on tungsten electrode proceeds via three-dimensional instantaneous nucleation with diffusion-controlled growth process. The average diffusion coefficient of Co(II) was found to be 7.5 × 10-8 cm2s-1 at 353 K, which is in good agreement with the estimated value from cyclic voltammetry. The electrochemical deposit was characterized using SEM-EDS and XRD methods. The SEM image shows formation of a dense and compact deposit at - 0.75 V. The EDS and XRD analysis confirm that the obtained deposit is pure cobalt metal.

Jan 1, 2015

By P. C. Holloway, A. Tshilombo, T. Xue, M. J. Collins, R. Lopetinsky, I. Mihaylov, I. M. Masters

The Voisey’s Bay deposit contains a trace amount of cadmium, which reports to solution during pressure leaching of the nickel concentrate at Vale’s Long Harbour Hydrometallurgy Plant, and must be removed to produce high quality nickel cathode. In 2006, Vale approached Sherritt Technologies to collaborate on the development of a process for removing cadmium to low levels (<1 mg/L) in the nickel raffinate. Following successful bench scale and pilot plant testing at Sherritt’s laboratories, the cadmium removal process was then moved through engineering and construction, culminating in the successful commissioning and startup of a cadmium removal circuit at the Long Harbour Hydrometallurgy Plant in 2017. This paper presents the results of this collaboration and the challenges that were encountered through each stage of development, as well as current results from operation of the commercial cadmium removal circuit. INTRODUCTION Vale’s Long Harbour Processing Plant, with a nameplate capacity of 50,000 t/y nickel, began operation in 2014. In addition to electrolytic nickel rounds, the plant also produces electrolytic cobalt rounds and copper cathode. The Long Harbour Processing Plant uses a unique hydrometallurgical process developed by Vale Base Metals Technology Centre, as shown in Figure 1, to treat a nickel sulphide concentrate produced at the Voisey’s Bay mine and mill located in northern Labrador (VBN concentrate) (Stevens et al., 2009).

Jan 1, 2019

By R Tweedie

&apos;The politics of mining in New Zealand&apos; is a topic I chose myself because of its importance in the future of the New Zealand mining industry. There are many people in the industry who are cynical about politics, cynical about politicians and definitely cynical and often critical of political decisions. In fact, many industry people say they don&apos;t want to get involved in politics, they just want to get on with the business of exploration or mining. The point of my address is that politics is important and the industry cannot afford not to participate in the political process.

Jan 1, 1991