• Solvent extraction procedure for the determination of tungsten in ores

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1970-11)
      Atomic absorption methods have not been widely used for the determination of tungsten in ores due to its low sensitivity in aqueous solutions (1). A method has now been developed for solvent extraction of tungsten, making rapid determination of tungsten at low concentrations possible. It was found that tungstates, when converted to phosphotungstates, can be effectively extracted into di-isobutyl ketone (2-6 dimethyl - 4 - heptanone) (DIBK) containing Aliquat 336 (methyl tricapryl ammonium chloride from General Mills). This system was effectively used for the extraction of gold from cyanide solutioins (2). Even in aqueous solutions, phospho-tungstates give greater sensitivity (37 µg/ml for 1% absorption) compared to simple tungstates (63 µg/ml for 1% absorption). Standard tungsten solutions for extraction studies were prepared by converting aqueous solutions of sodium tungstate to sodium phospho-tungstate by boiling with ortho phosphoric acid. A Perkin-Elmer Model 303 atomic absorption spectrophotometer was used with a nitrous oxide-acetylene flame at a wavelength of 4008.75 A.
    • Determination of molybdenum in geological materials

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1971-09)
      This paper will describe a method for the determination of molybdenum in geological materials. It is known that molybdenum as molybdate or phosphomolybdate ion can be extracted using the liquid ion exchanger, Aliquat 336 (methyl tricapryl ammonium chloride, available from General Mills, Inc. Kankakee, Ill.). Aliquat 336 has been used for analytical separation of gold, tungsten, and actinide-lanthanide elements.
    • The determination of titanium in titaniferous magnetite ores by atomic absorption spectrophotometry

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1972-03)
      Amos and Willis (1) first investigated the use of nitrous oxide for the determination of titanium. They found that the presence of HF and iron enhance the absorption of titanium. They recommended “much more extensive investigation before a practicing chemical analyst can determine this element in a routine fashion by atomic absorption.” Various authors (2, 3, 4, 5, 6) have investigated titanium by atomic absorption and have recommended a number of different procedures to remove interference. In attempting to analyze lithium metaborate fusions (7, 8) of titaniferous magnetite ores of Alaska by atomic absorption, it was found that the interferences are not completely removed by any single approach suggested in the literature. Silicon, iron and aluminum could vary widely between samples and an approach was needed that would completely eliminate interference effects of all these elements, without having to match the gross matrix composition of samples and standards.
    • Determination mercury in Alaskan coals by flameless atomic absorption

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1973)
      An oxygen combustion, double gold amalgamation system is constructed for the determination of mercury in Alaskan coals. Solutions have been found for certain problems in design and operation. The effect of operating variables have been thoroughly evaluated and analytical procedure is outlined. The system involves combustion of goal in an oxygen atmosphere and amalgamating mercury on gold coils. The amalgamated mercury is released by heating and measured in an atomic absorption cell.
    • Characterization of Alaska's coals

      Rao, P.D. (University of Alaska Mineral Industry Research Laboratory, 1974)
      Coal characterization is a systematic determination of those properties of coal, or of its constituents, that affect its behavior when used. It will help in planning for recovery and use of the extensive Alaskan coal deposits, which have proven reserves of 130 billion tons. This estimate is of necessity based on widely scattered outcrops and meager drill hole data, and the reserves in the Cook Inlet region and the Northern Alaska field are considered to be several fold this figure.
    • Mining in Alaska - environmental impact and pollution control

      Johansen, N. I. (University of Alaska Mineral Industry Research Laboratory, 1975)
      Environmental factors affecting mining are difficult to establish in Alaska due to the absence of large scale hard rock mining activities at the present time. Currently, experience is gathered from (and to a large degree based on) construction of above ground facilities such as roads, pipelines, and buildings. Past mining activities appear to have had little lasting effect on the natural environment, the exceptions being mine tailings and surface structures. This report, sponsored by the U. S. Bureau of Mines, present general engineering activities, considers the interaction of permafrost and underground mining, summarizes available literature and indicates possible environmental problems that might be encountered in Alaska based on Scandinavian experiences in large-scale northern mining operations. How the Scandinavians are solving their problems is also discussed.
    • Resume of high capacity gravity separation equipment for placer gold recovery

      Mildren, Jim. (University of Alaska Mineral Industry Research Laboratory, 1975-01)
      The phenomenal and meteoric rise in gold prices in the past few years has stimulated a renewed interest in domestic gold mining and many deposits once considered valueless or at best marginal at past gold prices are now potentially mineable at a profit and will become even more attractive if new and more appropriate technology can be found and applied. There have been many new innovations in gravity separation technology since the days of the gold dredge, and most of these have been developed outside of the U. S., where placer deposits are being mined and processed for various other minerals such as rutile, illeminite, zircon, cassiterite and even diamonds. Many of these newer methods could be very profitably applied to gold recovery in many present day placer or sand and gravel operations.
    • Current state-of-the-art in drying low-rank coals

      Rao, P.D. and Wolff, E.N. (University of Alaska Mineral Industry Research Laboratory, 1976)
      Research on drying of low-rank coals, such as lignites and subbituminous coals, has been conducted for nearly half a century. Although partial drying of Dakota lignite is practiced for freeze-proofing by mixing partially dried coal with run-of-mine coal, full scale drying of low rank coals has never been practiced commercially in this country. The reasons are: ( 1 ) drying of low rank coals by conventional methods results in severe degradation of coal particles; (2) dried coals are thus dusty and difficult to handle; (3) reabsorption of moisture in storage and transit defeats the drying process. In addition the dry coal particles will react with ambient oxygen, and heat up enough to ignite. It appears that large-scale development of Alaskan coals may have to await solutions to these problems. Our Mineral Industry Research Laboratory at the University of Alaska is making a comprehensive literature search seeking solutions to these problems and identifying areas of research that should be undertaken.
    • Sulphur isotopic evidence for the genesis of the Au-Ag-Sb-W mineralization of the Fairbanks mining district, Alaska

      Metz, P.A. (University of Alaska Mineral Industry Research Laboratory, 1984-10)
      Sulphur dioxide from sulphides was extracted for analysis by oxidation with Cuprous oxide at 1070º C, using essentially the method described by Robinson and Kusakabe (1975). The isotopic analyses of the purified sulphur dioxide were made on a modified Micromass 602 mass spectrometer with heated inlet system. The results were corrected for isobaric interference assuming a constant oxygen isotopic content and instrumental crosstalk (Coleman, 1977; 1980) and expressed in conventional del notation with respect to the Canon Diablo meteoritic troilite standard.