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By Emma Arakelova

An increase in concentration of a Zn-containing volatile complex for synthesis of ZnO films was investigated when processing their target by ultraviolet radiation emitted by mercury lamp. The experiments were carried out using a flow-type quartz reactor. ZnO tableted target was preliminarily irradiated during 2 to 7 hours. H2O2 (98%) vapor at 25Pa passed through the reactor with ZnO target at 373K. As substrate material, five subsequent quartz cylinders were used at 423K. The experiment lasts 4 hours. H2O2 decomposition on ZnO surface was accompanied by formation of a Zn-containing volatile complex which passed in gas phase and decomposed on the substrates with isolation of final ZnO. The concentration of the Zn-containing volatile complex (N) in gas phase increases with UV pre-irradiation time (t) (without irradiation N = 1.05 1011 particles/cm3; after t=2 hours, N = 5.19 1011 particles/cm3, after t=4 hours, N = 9.95 1011 particles/cm3; after t=7 hours, N = 1.86 1012 particles/cm3.

Jan 1, 2006

Recovery of Rhenium from Mineral Raw Materials of Kazakhstan

Sep 13, 2010

By Thys B. Johnson

Operations Research techniques for determining optimal shipping schedules and production and product allocation are discussed. A hypothetical mining operation model is formulated by the Bureau of Mines, and optimal production and product allocation are determined. The technique of sensitivity analysis is discussed and is used to illustrate the effect of the variability in a mining operation on the optimal production and product market plan.

Jan 1, 1969

By Daven N. Compton

The optical properties of Au nanoparticles have been known for some time, with both Au colloids and Au nanoparticles embedded in glasses having been extensively studied. In this study, Pt nanoparticles have been incorporated into Au colloids, and the linear and non-linear optical properties investigated. UV-VIS spectrophotometry, fluorescence spectroscopy and the z-scan method have been used to examine the effects of such additions.

Oct 1, 2003

By Jeanne A. Smith, Suzanne D. Smith

Annoyance, fatigue, and musculoskeletal pain have been reported during prolonged exposures to propulsion-generated vibration in military propeller aircraft1. The objective of this study was to determine the vibration mitigation properties of selected seat cushions and the effects of occupant seating posture during exposure to higher frequency multi-axis vibration associated with military propeller aircraft. Methods A Navy E-2C Hawkeye crew seat was mounted onto the Six Degree-of-Freedom Motion Simulator (SIXMODE). Six seat pan cushion configurations were tested during exposure to an E-2C vibration signal collected in the field1. Seat pan cushions 1 – 5 were used with the original E-2C seat back cushion. Cushion configuration 6 included seat pan cushion 5 with a prototype seat back cushion. Triaxial accelerometer pads were mounted onto the seat pan and seat back cushions to measure the vibration entering the human. Data were collected for seven subjects seated upright with their backs in contact with the seat (back-on) and not in contact with the seat (back-off). Spectral analysis techniques were used to analyze data at the two dominant frequencies associated with the propulsion system (propeller rotation frequency (PRF) ~18.5 Hz, and blade passage frequency (BPF) ~73.5 Hz). Overall accelerations were also calculated between 1 and 80 Hz. Vibration Total Values (VTVs) were calculated using the weighted seat pan and seat back (back-on only) accelerations and compared to the comfort reactions given in ISO 2631-1: 19972. Results In general, the highest accelerations observed at the seat pan occurred in the fore-and-aft (X) direction at both the PRF and the BPF for all cushions and both postures. The most pronounced effect was at the BPF in the X direction, where all configurations showed significantly lower seat pan accelerations than configuration 1 (original E-2C cushion) with the back-on posture. Configuration 5 was the exception with the back-off posture (Fig. 1A, Repeated Measures ANOVA, P<0.05). The most pronounced effect of posture occurred at the PRF in the X direction, where all cushion configurations showed significantly lower seat pan accelerations with the back-off posture (Fig. 1B). All configurations except configuration 2 showed similar VTVs as compared to Configuration 1 (Fig. 2, P<0.05). Configuration 2 tended to show the lowest weighted acceleration levels. The overall VTVs (back-on only, Fig. 2B) showed significantly higher accelerations as compared to both the back-on and back-off seat pan point VTVs (Figs. 2A &

Jan 6, 2006

By Dale S. Preece

The blast-induced movement and final location of geologic layers that may cause environmental problems can be predicted using discrete element methods. This prediction capability can be used by mine operators to locate the material in the muck pile during excavation which would allow encapsulation to prevent groundwater infiltration.

Jan 1, 1994

By I. Yildirim

Free energy of interaction between particles in water can be calculated if one knows the values of appropriate interfacial tensions, which in turn can be determined from the surface free energies of the particles involved. The latter can be determined using the Van Oss-Chaudhury-Good (OCG) equation. This method requires the measurement of contact angles of well-defined liquids on the surfaces of the particles of interest. In the present work, the contact angles were determined using heat of wetting, capillary rise, and thin-layer wicking methods. The results are compared, and the utility of the surface free energy data obtained from the contact angles are discussed.

Jan 1, 2002

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research (CFR) Committee of the Coordinating Research Council (CRC) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36.4/ Further reports were issued describing motor gasolines sold during the succeeding sum¬mers and winters to and including the summer of 1941.4/ No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed.!The present report presents analytical data for 4,544 samples, represent¬ing the products of 124 companies. The samples represented in this report were obtained during December 19146, January and February 19-(. As in previous surveys, the companies covered Ly the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium-price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gasoline are not considered adequate to represent this type of motor fuel, data for the analyses have not been averaged, but the individual items are tabulated. The number of samples, items, and brands comprising each group is as follows: Regular-price, 2,368 samples, 319 items, and 113 brands; premium-price, 2,172 samples, 289 items, and 106 brands; third-grade, 4 samples, 4 items, and 4 brands. The meanings of these terms as used in the surveys are as follows:"

Aug 1, 1947

[Dr. N.A. Barcza (Chairman) Mr. R.J. Linnell (Vice Chairman) Mr. J. Basson Dr. L.A. Cramer Mr. W.A. Gericke Dr. N.C. Machingawuta Mr. C.S. Mahony Dr. L.R. Nelson Mr. D. St J. Slater Mr. B.J. van der Walt INFACON X TECHNICAL PROGRAMME COMMITTEE Dr. L.R. Nelson (Chairman) Mr. W.A. Gericke (Vice Chairman) Mr. W. Barrett Mr. T.R. Curr Dr. O.F.R.A. Damm Prof. R.H. Eric Mr A.M. Hearn Mr. A.R. Jamieson Dr. N.C. Machingawuta Mrs. L. Mthombeni Mr. F.X. Prins Mr. J. van Tonder ]

Jan 1, 2004

Jan 1, 1960

By John P. Powell

The increasing demands for petroleum and its products and the steadily increasing cost of discovering and developing new oil fields are factors that emphasize the importance of increasing the recovery of oil from known petroleum reserves. Water flooding is a valuable conservation measure, not only preventing premature abandonment of stripper leases but also reviving interest in many areas previously abandoned. The use of water flooding as a means for recovering additional oil from partly depleted oil-bearing formations was first tried in Oklahoma in 1931. Early water-flooding operations were confined to the area of shallow Bartlesville-sand formations in Nowata and Rogers Counties, where many of the projects were outstandingly successful. The results of these operations stimulated activities in other pools in Oklahoma, and by the end of 1949 water flooding had been tried in 25 of the 49 oil-producing counties in the State (fig. 1). Approximately 33 million barrels of oil, or 1,806 barrels per acre, had been recovered by December 31, 1949, from 18,221 productive acres included in the 162 active and abandoned projects in Oklahoma by injection of approximately 449 million barrels of water.

Jan 1, 1952

The Ngakuru zeolites are located about 20 km south of Rotorua and comprise a number of deposits dispersed along several fault lines. Relatively recent volcanic activity (250,000 years ago) resulted in ash depositions that vary in depth and mineralogy. Subsequent variable thermal alteration intensities generated predominantly clinoptilolite and mordenite zeolites with a range of physical characteristics. Typically the zeolites have low density (650 kg/m3), have high liquid (60% of dry weight) and odour absorption characteristics, and a high affinity for soluble cations (CEC =: 100 meq/100 g). Traditional kitty litter and oil absorbency markets are being expanded. New opportunities in waste and potable water treatment, organic and synthetic slow release fertilisers, use as a light weight aggregate for speciality concretes, and pozzalome activity are currently being researched.

Jan 1, 2000

By H. Seguin, J. A. Le Gac, S. Bernhard, P. R. ZETTWOOG

The "Service de Protection Technique"of the "Institut de Protection et de Sûreté Nucléaire" was asked by the Commission of European Communities to conduct measurement campaigns which would make it possible to evaluate, on an experimental basis, the collective risk to miners exposed to radon in underground, non-uranium mines located in countries within the European Community. 1. METHODOLOGY USED TO CONDUCT THE CAMPAIGNS This campaign is original in that direct measurements of the individual monthly exposure to potential [a]-energy from short-lived radon daughters are made using personal [a]-dosimeters described previously (1). We call this type of dosimetry "personal dosimetry". The workers who wear the personal [a]-dosimeters were selected taking into account the various categories of workers and their work assignments in the various areas of the mine. Another way of finding out the occupational exposure of these miners consists in making numerous measurements of the radon concentration at the various work places, taking into account the time spent at each place by each worker. This procedure is too complex for an evaluation of the collective risk as requested by the Commission of European Communities and was therefore rejected. Additional data was gathered during these measurements campaigns using the following techniques (table 1). [ ] (1) Current [a]-dosimetry as practiced in France - SPT international report N° 234 - February, 1981 - P. ZETTWOOG The mines were chosen to include a larger variety of types of ore, of geological situations, and of mining methods. 2. RESULTS OF THE RADON DATA-GATHERING CAMPAIGNS 2.1 – [Uranium content of the surrounding rocks and ore] The samples taken during the campaigns make it possible to establish the U content in the rocks of the mines selected. These values, from 2 to 15 ppm, are slightly higher than those usually found (2 to 5 ppm) (table 2). [ ]

Jan 1, 1981

By Tony A. Rorke, Joe R. Brinkmann

The application of instrumentation to better understand and improve production blasting is one of the most fruitful areas of explosives and blasting research. The majority of instrumented studies of production blasting have relied on the extrapolation of far field measurements to postulate blast performance in regions of interest closer to the charge where rock breaking takes place. However, the nonlinear and dissipative nature of the quantities being measured raises serious questions as to the accuracy and validity of such extrapolations.

Jan 1, 1991

By Kari Moen, John Rasmus Leinum, Jarle Hjelen, Terje Malvik

"Industrial minerals may contain the same elements in approximately the same amount. In these cases backscatter electron imaging or chemical analysis are not sufficient to identify the minerals. Another problem arises when micro textures are not detectable in traditional imaging or the grain size is smaller than the X-ray spatial resolution.As a supplementary technique in these cases, application of crystallographic information by electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM) may be a suitable method. The technique has been demonstrated on three Norwegian mineral raw materials and one Italian marble and shows that it has some advantages compared to traditional techniques.• quantitative measurements by ebsdCommon automatic techniques describing the mineral contents and the occurrence of minerals in free and locked particles, are based on optical-, backscattered electron (BSE)- or X-ray-signals. There are various commercial software systems on feature analysis by backscattered and X-ray signals in combination with image analysis (e.g. Oxford Inca Feature, CSIRO QemScan).Especially in silicates, the occurrence of similar elements in the different minerals is common. Sometimes the various minerals not only contain the same elements, but also approximately the same amount of each element. In these cases BSE imaging and chemical analysis are not always sufficient for identification."

Jan 1, 2003

There is wide agreement that sustainability has multiple dimensions, but substantially less agreement on the appropriate balance among those dimensions. This occurs because peoples’ vision of a sustainable future, their goals for sustainable development, and their objectives for resource management are reflections of their values, culture, and life experiences. Even assuming agreement about the objectives of sustainable resource management can be reached; there is still a need for policy and decision makers to choose from among alternative courses of action, each of which has its own set of impacts and outcomes. One of several tools used to compare the consequences of alternative actions is the Computable General Equilibrium (CGE) model. This paper uses CGE modeling to demonstrate how policy decisions do not take place in a vacuum and how policy-makers must be aware that there are trade-offs involved in any decision.

Jan 1, 2005

By Malcolm Mudge

"One of the oldest mining areas in the World exist in Africa and the Middle East. This area is being exploited by foreign and local mining entities. Several large plants, both foreign and local as well as small operators, conduct their mining business on a scale which would be could be prohibited in any other part of the world. Relatively recent European disaster with tailing disposal and breakout has highlighted the problem.More important to the author is that the presence of foreign entities in zones which have not remedied the situation but has heightened the concern due to those entities using similar outrageous methods in treatment of waste. The abject misuse of technology cannot be permitted to continue and the lack of any metallurgical knowledge in the treatment of gold ores is considered deplorable for the majority of third world countries.The destruction of cyanide is simple and straightforward and requires no special skills. In South America, we developed a system that is modular, compact and can be operated in batch mode to cater for several clients, as required. Larger installations would require a separate module, as treatmentwould be on a continuous basis."

Jan 1, 2003

The Bibliographic Data Base contained in the present volume is the result of a literature search conducted as one task of the Bureau of Mines project concerned with research in borehole assay technology. The data base includes articles, symposia, books, corporate and government reports, patents, and other literature concerned with some aspect of borehole logging, from January 1969 through December 1975. Occasional updating to keep the data base current is anticipated. The remainder of the intro¬duction will be devoted to the explanation of the organization of each entry, along with the translation of terms and abbreviations used in the text. Each entry contains six sections. These include an ID code, a title, an author section, a source section, an abstract, and a descriptor section. The first item listed in an entry is the ID code. This serves to identify an entry. It consists of the first six characters of the first author&apos;s (or editor if no authors are involved) last name, along with the last two digits of the year of publication. A letter sometimes follows the year of publication to assure a unique alphanumeric code. For example, if an author named Wilson writes more than one piece of literature in a given year (for example, 1972), the ID code for the entries identifying these pieces of literature would be identical. Therefore, to allow for unique ID codes, the first piece would he identified as "WILSON 72,&apos;, the second piece as "WILSON 72A", the third "WILSON 72B", and so on.

Jan 1, 1976

Correlation of Air Recovery with Thin Film and Froth Stability in Flotation

Sep 13, 2010

By D Craw

Oceana Gold as part of their environmental strategy are looking at various methods for cost-effective revegetation of their tailings dams. Under the concept of revegetating the tailings this study looked at several issues. These issues were; testing different methods of revegetation, arsenic (As) uptake in vegetation with respect to capping thickness, and background As levels in farmland areas above mineralised rocks. A number of plots were set up in a temporarily disused tailings dam to trial the direct sowing of ryecorn into the tailings. &nbsp; Ryecorn was sown in sandy tailings (ca 1000 mg/kg As) and then covered with oxidised schist to anchor the seeds. This proved successful and ryecorn was established. Once the plots covered with oxidised schist were growing, 1 m and 2 m strips were sown on the sheltered side of the existing plots without the covering of oxidised schist. The uncovered plots also established successfully. From this set of trials a sowing plan can be developed that uses a minimum of resources to successfully establish vegetation. The maximum As content of the ryecorn was 80 mg/kg. Clover, Yorkshire fog and ryegrass plant matter was sampled from a pot trial that used different thicknesses of topsoil covering tailings material. As the thickness of topsoil increased, the amount of As taken up decreased. Soil samples were taken from farmland areas which were known to have elevated levels of As (up to 1000 mg/kg) in the top 10 cm. Vegetation samples were also taken from the same locations, and show the As levels in plants is &lt;50 mg/kg.

Jan 1, 2006