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By Jess H. Albino, Girish Roy, James M. Monsees

Construction of the North Hollywood line of the Los Angeles Metro System required crossing the Hollywood Fault as the twin transit tunnels extend into the San Fernando Valley. The Hollywood Fault is considered active and represents the largest active fault that the North Hollywood Redline extension will cross. The feature is a thrust fault with the north plate overriding the southern plate and creating the Santa Monica Mountains in the process. South of the fault lies the alluvial valley and Hollywood. North of the fault are the Santa Monica Mountains which rise locally to more than 1200 feet. The average overburden at the seismic section is about 300feet and is overlain by Runyon Canyon Park, a municipal park with environmentally sensitive areas. The actual fault plane was anticipated to lie within the southernmost120 feet of the 600 to 700-foot-wide fault zone. The special seismic section constructed for the tunnels consisted of an enlarged cross-section with special lining, drainage and finish features that will facilitate the restoration of metro service in case of a major event occurring on the Hollywood Fault. The discussion will address the geology, the procedure used to define the design event and predicted displacements, the unique design features as well as the construction methods used and the instrumentation and the results obtained.

Jan 1, 1999

By J. B. Hiskey, P. H. Qi

Activated carbon loaded with gold from different halide solutions was characterized by thermal analysis (TA) techniques. The mechanism of gold uptake by carbon varies from predominately adsorption for gold iodide to predominately reduction for gold chloride. Thermogravimetry analysis (TGA) and differential thermal analysis (DTA) measurements confirm the existence of adsorbed gold-halide species within the micropore structure of carbon. These results suggest that the ratio of reduced to adsorbed gold increases for gold halides in the following order: Au-I < Au-Br < Au-Cl. In the case of Au-I, TA results for the loaded carbon were compared with pure compounds of 12, Aul and Aul3.

Jan 1, 1998

By Arthur R. MacPherson

Este capítulo revisa las etapas que deben seguirse desde el momento de considerar la molienda autógena en el desarrollo de un nuevo depósito de mineral o en la expansión de una planta existente, hasta la compra de un molino autógeno. En este caso el término autógeno incluye: semi-autógeno, molinos de pebbles secundarios y molino de bolos (trozos), así como los sistemas de molienda autógena total. También se han incluido las alternativas por vía húmeda y seca. Antes de programar el ensayo debe decidirse cuantas muestras brutas son requeridas para calcular propiamente las posibilidades de molienda autógena del depósito. También ha de tomarse la decisión, de como y donde deben tomarse las muestras, por ejemplo: planta piloto situada en el sitio de localización de la planta o en otro lugar establecido; molienda en húmedo y/o en seco....etc. En el mismo programa del ensayo se obtendrán ciertos datos fundamentales. Los ensayos deberán incluir un trabajo suficiente. para determinar cuál de las moliendas, totalmente autógena o semi-autógena, debe utilizarse; y qué tipo produce la máxima eficacia en la potencia consumida. También, los otros datos pertinentes deben ser recolectados, como por ejemplo: potencias, tonelajes, alimentación, carga, tamaño del producto, carga circulante, etc. Si es necesaria una molienda secundaria para obtener el tamano final, la decisión de qué molienda debe emplearse (molino de pebbles o molino de bolas) puede requerirse un ensayo de trabajo adicional. Finalmente, la concentración del mineral puede jugar un papel importante en la selección del circuito y debería ser una parte del ensayo final una vez que se ha establecido la molienda. Para determinar qué tipo de molinos pueden satisfacer los requerimientos establecidos por la planta piloto, debe tomarse una escala para ciertos datos como: potencia del molino, consumo de acero, simple o doble etapa de molienda, tipo de molino secundario. Para asegurar un posterior entendimiento del depósito de mineral y sus características de molienda, deberán efectuarse algunos trabajos adicionales a pequena escala utilizando pequeñas muestras y molinos para producir unos datos comparables de molienda. También, algunos ensayos tales como medio de molienda óptimo, e índice de trabajo, deberán ser completados.

Jan 1, 1982

By J. W. Wilson, Y. Ding

In the ultrafine coal-cleaning process, small coal particles (-400 mesh) are produced during the pulverizing operation. After the coal-cleaning process, these ultrafine particles are very difficult to dewater and create problems in coal transportation, storage and handling at utility plants. Research on ultrafine coal dewatering and briquetting resulted in the development of a single-stage operation that is potentially more effective and economical than conventional thermal drying and briquetting processes. The final coal product has a moisture content of less than 15% and possesses high strength and water resistance that satisfies coal transportation, storage and handling requirements.

Jan 1, 1996

By P. Magnani

Quarry environmental reclamation can be achieved with favorable economical advantages and high energy efficiency, using stabilized materials obtained by the treatment of organic fraction of municipal solid waste (MSW).

Jan 1, 2005

By Andrew M. Garvie, William W. Plotnikoff, Eugenia Y. Kuo

Water infiltrating the surface of waste rock dumps transports pollutants into the environment. Lysimeters have been used to quantify the infiltration rate. To date their design has been guided by modeling under steady-state conditions. Recently a two-dimensional finite element code has been developed to model the response of lysimeters to time-dependent infiltration rates. It was used to investigate the response of lysimeters installed in a waste rock dump and subject to a monsoonal rainfall pattern. The results are presented and compared with field data.

Jan 1, 2000

By J. Brinen, D. R. Nagaraj

Secondary Ion Mass Spectroscopy (SIMS) was used to study copper ion adsorption, and its effect on subsequent sulfide collector adsorption, on pyrite and pyroxene minerals under flotation related conditions. Copper was found to adsorb on both of these minerals and cause enhanced sulfide collector adsorption. The distribution and depth profile of copper and collector on these mineral surfaces were obtained by using SIMS in the imaging mode. The results of this study have provided a valuable insight to understanding pyrite and gangue flotation observed frequently in operating plants.

Jan 1, 1995

By L. Alan Weakly

Page one is missing from book

Jan 1, 1982

By M. Phillip Jameson, Paul Sennett

The beneficiation of kaolin by flotation has been practiced on an industrial level since 1961. A brief history of industrial kaolin flotation is given, with a description of the various processing schemes used by the companies that practice kaolin flotation. Some of the areas where improvements could be made in the beneficiation of kaolin are given.

Jan 1, 1989

By C. L. McKenzie, R. A. Heig

The design and operation of metallurgical laboratories is discussed. Laboratory size, general laboratory equipment and metallurgical staffing are discussed from a standpoint of desired laboratory results.

Jan 1, 1986

By Otis M. Clarke

The 34th Forum on the Geology of Industrial Minerals gave members a chance to see the geology of various stone and ore deposits displayed graphically in quarry walls and also provided an opportunity to hear and see first-rate papers and posters on the geology of industrial minerals. Also, some field trips passed through areas of spectacular scenery. As a bonus, participants saw scenic mines, some of which are "pretty as a picture." Watercolor paintings prove it. At the Oklahoma Forum, the writer displayed a number of paintings of mines and other landscapes seen during previous Forum trips. These paintings and this brief article are part of a crusade to prove that some mines and geologic vistas are scenic wonders and belong in our visual heritage. It is a plea to save some of our best geologic exposures for future geologists, tourists, and artists.

Jan 1, 1999

By Paul D. Tomlingson

Will Rogers unwittingly commented on the essence of evaluations when he said: "We don&apos;t know what they don&apos;t know!" In so doing, he explained why managers have an obligation to verify that their personnel really know what is expected of them. Rogers further stated that "What we know may not be so!" Here, he suggests that managers must establish the correctness of facts on which they make decisions concerning the future of their organizations. Yet, there are some managers who may not have considered this basic wisdom. These are perhaps the ones who shun a solid, fact-finding evaluation. Instead, they trust to guesswork as a basis for attempting improvement. Without realizing it, they may be making incorrect decisions harmful to the very organization they are trying to improve. Unfortunately, an attitude of avoiding evaluations often permeates whole organizations when their managers fail to appreciate their importance. Recently, the following was found prominently displayed in the office of a maintenance manager. Regrettably, the facts of a subsequent evaluation established how imprudent his attitude was:

Jan 1, 1991

By B. K. Mishra, R. K. Rajamani

This paper focuses on the use of a numerical tool known as the discrete element method (DEM) to study the motion of ball charge in ball mills. DEM is employed to simulate the motion of individual balls. While doing so, the effect of liner design on the grinding performance of the mill is studied. Two important, factors, such as the configuration of the liner and the geometry of the lifting surfaces, are correlated with the overall mill performance. An attempt is made to show the effectiveness of the lifter bars in transmitting power from the mill shell to the interior of the mill, with particular emphasis on large diameter mills.

Jan 1, 1994

By Robert McEwen

Conveyor equipment beyond its prime chronically suffers from a lack of understanding in today&apos;s plant environment regularly delivers more material than original designers ever expected. A case in point is a belt conveyor in a major hard rock mine/milling operation asking to bring the unit up to current standards while eliminating spillage and reducing airborne dust. The challenge was to keep the system going by revamping the system while keeping the same footprint and allowing for higher production rate. Thirty years of daily maintenance and dust collection costs have virtually disappeared by the end of this challenging upgrade.

Jan 1, 2008

By Menzhans Guo

A coal bunker basically acts as a buffer and regulator to reduce the interruptions between its proceeding production system and succeeding haulage system so as to maximize the availability of the whole system. Although such a role has long been recognized, quantitatively studying it is still rarely seen in the literatures. Its unique characteristics, coupled with numerous transitional states, make it very complex to describe the state transitional process in analytical models and, also very difficult to seek an analytical solution. Moreover, the analytical models inappropriately consider the state of bunker being full or empty as a kind of failure, therefore, by no means can they realistically describe the impact of the difference between rates of coal flowing to and from a bunker on the system availability. In light of this, Monte Carlo simulation methods are suggested to reach an approximate solution. In comparison, simulation methods are simpler and more effective than analytical approaches. Applications of simulation methods to a Northern colliery for determining bunker size from the viewpoint of maximizing system&apos;s availability are discussed. The results are satisfactory.

Jan 1, 1992

By Hugh K. Herbert, R. John Watling

Laser Ablation-Inductively Coupled Plasma-Mass Spectrom­etry (LA-ICP-MS) has been used successfully to "fingerprint" gold in forensic investigations within Australia and abroad. By comparison of the elemental associations it has been possible to relate gold to specific mineralising events, mines, bullion samples and fabricated articles. The methodology facilitates identification of the provenance of gold thereby providing definitive scientific evidence in criminal investigations. "Gold" samples for analysis span a wide range of materials with many requiring exhaustive prior separation and treatment to present the contained gold in a chemically "unmodified" state, and in a form, suitable for LA-ICP-MS fingerprinting. The quality of the fingerprint, and hence its value in evidence, is directly related to the rigours of prior sample preparation and evaluation, to an appreciation of the history of the gold under investigation, and to the skill of the analyst.

Jan 1, 1995

By Yoginder P. Chugh

The mining methods used at many opencast brown coal mines in Poland and the German Democratic Republic are not used in the US to any extent. Using bucketwheel excavators, bucket chain excavators, and mobile conveyor bridges, the mining techniques may offer efficient, economic alternatives for operators in the US. These mining methods were observed during visits to several open-cast brown coal mines in Eastern Europe over the past two years. Some of them may be particularly attractive for the large lignite mines being planned in North Dakota and Texas.

Jan 11, 1980

By A. G. Wylie

The dimensions and shape both airborne and bulk amphibole-asbestos fibers are different from those of both airborne and bulk of cleavage fragments of the amphiboles. These differences are related to the mineralogical properties unique to the habit of asbestos, including the fibrillar structure, small fibril widths and distinctive crystal-lographic faces of fibrils. Criteria for distinguishing amphi-bole cleavage fragments from amphibole-asbestos include mineralogical properties observable in bulk samples and the dimensions of particles collected on air filters. It would be it very helpful to the mining and mineral industry lf these properties were recognized in the regulation of asbestos.

Jan 1, 1987

By A. S. Mallicis, Li Xiawoei, P. W. Weiblen, I. Iwasakl

Platinum group metals (PGM) are often found in close association with arsenide and sulfarsenide minerals in copper-nickel bearing gabbroic rocks. Major losses of platinum in flotation have been attributed to the susceptibilities of the arsenic minerals to oxidation and subsequent losses of their recoveries in cleaner flotation stages. The use of a nitrogen atmosphere in grinding and in flotation, the effectiveness of activation for improving their floatabilities, and the role that electrochemical interactions play not only between grinding media and minerals, but also among different minerals, are discussed.

Jan 1, 1989

Geopolymerization is a process by which Al-Si minerals undergo dissolution and polymerization in an alkaline solution to form a monolithic material with a high mechanical strength (Davidovits, 1991, 1994). In this study, the factors affecting the geopolymerization of Na feldspar (albite) and K -feldspar (microcline) were investigated. It was found that both Na feldspar and K -feldspar are reactive in geopolymerization with the resultant geopolymers showing a high compressive strength. The leaching ability, the proper molar ratio of Si/Al in the geopolymeric gel phase and the higher average hardness of the undissolved particles remaining in the geopolymers are found to greatly affect the ultimate compressive strength of the formed geopolymers. Key words: Geopolymerization, Mineralogy, Albite, Microcline

Jan 1, 2003