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By M. W. Harmer, J. M. Quist

Laboratory test work, pilot plant testing and plant experience with wet, fine-mesh screens are discussed. High-frequency, low-amplitude, fine-mesh, wet screens were installed on the 6th cleaner concentrate stream. These screens produce a 60% oversize recovery split of the molybdenite concentrate that is of leached equivalent quality. The undersize stream is leached with hot ferric chloride to remove lead and copper contaminants before roasting or shipment to sulfide customers. This plant modification is a good example of using existing technology in an unconventional flow sheet to yield significant cost savings.

Jan 1, 1991

By Richard R. Klimpel

This paper discusses the use of froth flotation as a means of removing metal containing species from a variety of feed streams that generally fall into the classification of waste streams. The variability in solid composition, degree of oxidation, water chemistry, and levels of organic/inorganic contaminants associated with waste streams implies that the collector chemicals used in any flotation process must be much more selective than typically required in normal mineral ore flotation systems. Several examples of such work currently underway will be illustrated showing the potential of flotation to upgrade metal-containing waste streams.

Jan 1, 1992

By M. I. M. Darwish

In this paper, an effort was made to get more in-sight about the parameters that can affect air sparging technique optimization. Numerical simulations were used in predicting the effects of different parameters utilizing Shell?s in house MoRes simulator. The case of using air sparging to remediate source zone is considered in this work. Different air injection scenarios using continuous and pulsed air injection techniques, with different frequencies and durations, were compared. The amount of MTBE mass removed from the saturated zone and arrived to the ground surface, through the vadose zone, was the main criterion while comparing different air injection scenarios. The simulations results showed that pulsed air injection is better than continuous air injection in removing the MTBE and that the longer the OFF time is the better the MTBE removal.

Jan 1, 2008

Council and Standing Committees - 1982/83 President: Prof. A. N. Brown Vice Presidents: Prof. R. P. King and J. D. Austin Honorary Treasurer: Prof. D. G. Krige Immediate Past President: G. Y. Nisbet Members of Council: B. C. Alberts, R. H. English, P. T. Fewell, C. E. Fivaz, J. S. Freer, Prof. G. G. Garrett, J. J. Geldenhuys, Dr A. K. Haines, P. N. Harris, H. E. James, Dr B. K. Loveday, Dr J. Lurie, D. G. Malan, G. Pienaar, B. E. Protheroe, Dr 0. K. H. Steffen, G. C. Thompson, Dr H. Wagner, Dr P. T. Wedepohl. Chairman, Witbank/Middelburg Branch: H. C. van Zyl.

Jan 1, 1983

By S. L. Jung, T. L. Nichols, K. Prisbrey

The problem was to evaluate the on-line detection of rock properties through acoustic emission sensors. Acoustic emission sensors, when attached to crushers, grinders, and roof bolters, are robust, economical, and relatively maintenance free. Our objective was to relate acoustic emissions to rock fracture mechanisms, including micropore closures, linear elastic deformations, and crack propagation. We evaluated acoustic emissions from steel jacketed rock cores during indentation tests. In addition we attached sensors to the rotating shaft of a rock bolter drill. A back propagation neural network "learned" rock fracture characteristics and rock type with 99% classification accuracy. A neural network's calibration and computational abilities suggest better acoustic emission sensor capabilities.

Jan 1, 1993

By R. D. Lama

This paper presents the results of a large scale trial of polycrystalline diamond picks (PDC) on longwalls with particular reference to dust control. Results from fixed position monitoring showed that PDC picks produced less respirable dust than tungsten carbide Point Attack picks. Dust generation at the longwall face was lower by 39 - 43%. Field trials also indicated that the life of a PDC pick to be at least 1460 tonnes/pick.

Jan 1, 1993

By Victor Phillips, J. P. Blair

Jan 1, 1952

By J. H. Wernick

IN a study of the rate of decomposition of ½ -in. cubes of limestone, dolomitic limestone, and dolomite in a sweeping nitrogen atmosphere, Joseph, Beatty, and Bitsianesl found that the zone of calcination advanced at substantially a constant rate at a given temperature. The purpose of this paper is to show that their data indicate at least two processes occurring when the above carbonates decompose. It is suggested that there are two processes occurring temperature range and the other the limiting process over another temperature range. The data of Joseph and co-workers have been extended by use of the Arrhenius equation, Eq. 1, a relation beween the velocity constant k of a reaction and the absolute temperature T.

Jan 7, 1954

By Kathleen M. Kowalski-Trakofler

This paper discusses human judgment and decision making under stress. The authors review selected recent literature across various disciplines and suggest a definition of stress within the context of decision making during the management of emergencies. They also discuss fieldwork by the Pittsburgh Research Laboratory, NIOSH, which explores traumatic incident stress, the relationship between previous training and performance under stressful conditions, and human behaviour in underground mine fires. The authors assert that stress is one of the factors that decision makers must contend with in most life-or-death situations. They suggest that a better understanding of individual judgment and decision making activities whilst under stress would yield a better understanding of how people reach the choices they make in emergencies. This enhanced understanding would be of enormous value to emergency managers, researchers and policymakers.

Jan 1, 2003

By C. L. Baker

The total production of petroleum in the Gulf Coast in 1927 was 54.541.180 bbl., .5.655.665 bbl. more than in 1926. The Texas total was 49.129.910 bbl. (Table 1) and the Louisiana tota1 5.411.270 bbl. (Table 2). Louisiana production decreased 278.028 bbl., compared with that of 1926. Spindletop produced nearly 44 per cent. of the Texas total. Initial production in Louisiana amounted to 62.865 bbl. and in Texas to 352.955 bbl.' The Oil and Gas Journal gives a total of 1145 wells

Jan 1, 1928

By F. G. Robb, D. N. Madge

This paper details some of the specifications and problems associated with implementing on-line control of a potash concentrator. The computer system described has the capability of three levels of control, including DDC with a single central processor. The system is also capable of on-line program compilation and modification through an extension of vendor utilities. The system is now in operation.

Jan 1, 1969

By R. F. Korcak

There exists a wide array of industrial byproducts that produce beneficial responses in the soil/ plant environment. These materials range from clean-coal-technology residues produced during the generation of electric power (particularly those high in gypsum) to mineral fines produced by the aggregates industry (i.e., sand, gravel and crushed stone). A number of these materials are examined in relation to potential nutritional interactions in soils and crops with emphasis on trace elements. The significance of utilizing these materials in agriculture as a component of sustainable agricultural systems are discussed.

Jan 1, 1997

By George Schore

Radiation grafting of ion exchange structures contains ion exchange groups but may consist of neutral groups. High energy grafting of monomers on to polymers has-been known since 1950 (1.2); manufacture on an industrial level was-begun in 1970.(3) Proper choice of substrate and monomer will produce various ion exchange membranes with differing physico and chemical properties. Grafting a selected monomer to the proper polymer will provide selective ion exchange with assured chemical protection of the substrate. Ion exchange systems utilizing radiation grafted structures to polymers have been fabricated to "capture" gold from drag-out and rinse water and silver from cyanide rinse water. Other ion exchange systems can feasibly be produced to remove other precious metals. Rotating Cathode Technology is used to recover the metals from their concentrated eluating solutions as pure metal foil.

Jan 1, 1984

PREFACE During the past year, the Council of the SAIMM undertook a major strategic-planning exercise to review all its current activities, and to redefine its scope and objectives in the light of changing circumstances. The following are the four main concerns that prompted Council to take stock of the situation. (1) Over the past five years, the SAIMM has become heavily involved in a variety of new activities. (There are many examples, of which the expansion in book publications and the establishment of physical metallurgy as a third major discipline with its own colloquia and schools are perhaps the most important.) While these new activities have considerably broadened the SAIMM's scope, they have resulted in a significant increase in the day-to-day workload of the President, Office Bearers, and Council members, and of the secretarial staff based at Kelvin House.

Jan 1, 1986

By David A. Summers, John Corwine, Li-King Chen

The results from fracturing plexiglas beams are combined in eight existing equations to determine the surface energy of the material. The reliability of each equation is tested, and the equation in use to determine fracture toughness is found to be the most exact. This equation is then used in determination of the surface energy of Barre Granite.

Jan 1, 1971

By Houghton BF

Ruapehu is an extremely active andesitic composite volcano, built in at least four cone- building episodes over the last 250 ka. The volcano was constructed by a variety of extrusive and subplinian, strombolian, phreatomagmatic and dome-related explosive eruptions from summit, flank, and satellite vents. The volcano may be subdivided into the cone itself, of volume 110 km3, and a surround- ing epiclastic ring plain of similar size. Four facies associations can be recognised at Ruapehu,-two each on the cone and on the ring plain. Neither cone nor ring plain provides a complete record of the history of the volcano. The cone is dominated by the products of extrusive eruption, as primary pyroclastic deposits are seldom preserved, being rapidly removed by erosion from the steep water- saturated and/or snow-covered flanks of the cone. The ring plain consists of the products of mostly explosive activity forming an alter- nation of primary pyroclastic fall deposits and material transported from the cone by lahars, floods and debris avalanches and then rapidly reworked in sediment-choked hyperconcentrated Streams.

Jan 1, 1987

By C. F. Chung

This paper will discuss an application of multivariate discriminant analysis to aid in predicting mineral potential from regional geological data and information on mineral deposits, with particular emphasis on the use of the logistic discriminant function. Logistic discriminant analysis is a generalization of standard discriminant analysis in that the discriminant analysis becomes applicable under a much wider class of distributions. As a practical example, the standard multiple discriminant analysis and the logistic discriminant analysis are applied to data from the Bathurst area in the Appalachian region of Canada and the results are compared with one another.

Jan 1, 1977

By Gary L. Self, Ronnie Daniel

With the advent of large scale blasts utilizing overburden casting techniques, it was imperative that an ultra reliable surface delay system be developed. Shock tube and detonating cord surface delay systems have been hampered by the lack of a reliable easy-touse method of incorporating multiple paths of initiation to each hole. Two new redundant nonelectric delay systems have been developed utilizing multiple signal paths to allow a higher degree of safety and reliability. The first system designed uses a combination of detonating cord and nonelectric shock tube delays to allow multiple delay paths to each hole. The second system incorporates a new all shock tube delay system which allows multiple delay paths while minimizing over-pressure by eliminating detonating cord trunk lines. These two redundant systems have been used in over 500 production blasts without any misfires due to surface cut-offs or detonator malfunctions.

Jan 1, 1989

By R. D. Begley, A. W. Khair

This paper presents an assessment of modeling techniques in predicting subsidence over longwall areas. Extensive instrumentation has been made, both at the surface and subsurface, at three longwall mines in northern West Virginia. Ground movements were monitored during a three- year period until subsidence ceased in these areas. A comparative analysis of empirical subsidence prediction techniques including graphical (NCB), profile function, influence functions (USBM, Bals', Knothe's, and zone area) will he presented. A brief geologic and topographic description of each site, along with the instrumentation and monitoring program, will also he presented.

Jan 1, 1990

By Catherine T. Aimone

A computerized cost model has been developed to simulate the technical and economic effects of strip mine blasting in the vicinity of structures. Current surface mining regulations restrict the allowable level of production blasting as a function of this distance. Blast design modifications,' therefore must be employed when blasting in the vicinity of homes to ensure compliance with federal and state regulations specifying limits to the seismic effects generated from a blast. The blasting level allowed. is computed by the charge weight of explosives per delay from the following scaled distance formula: [ ] where W is the charge weight per delay, in kilograms (pounds), D is the distance factor corresponding to the regulatory limit of peak particle velocity to which a structure may be subjected to. Current regulations specify 2.54 cm (1.0 in.) per second corresponding to a SD factor of 27 (60) (Federal Register, 1977).

Jan 1, 1982