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Unless otherwise indicated, pounds are US avoirdupois, feet are US, and gallons are US.

Jan 1, 1985

By K. G. Colman

Este texto intenta facilitar al operador y contratista 10s datos básicos para dimensionar las cribas vibrantes que deban ser utilizadas en las plantas de trituración. Las capacidades básicas, factores que la modifican .... etc., utilizados en el cálculo de la superficie requerida, se han desarrollado empíricamente y modificados sus valores hasta el presente con 10s datos de las aplicaciones prácticas Hay que señalar que el cribado tiene mucho más de arte que de ciencia exacta; sin em- bargo, la información aquí presentada proporciona una razonable seguridad cuando se aplica al cálculo de cribado de minerales metálicos.

Jan 1, 1982

By Rick Sarkisian, Greg Girardey, David Keech

The Conveyor Equipment Manufacturers Association (CEMA) specification B105.1 "Welded Steel Conveyor Pulleys" adequately defines pulley assembly standards for light material handling applications. However, most mining applications demand pulleys of higher reliability and load capacity than that offered by CEMA standard pulleys. Various sources have published specifications for "Engineered" conveyor pulleys. Typically, these specifications require T-section type pulleys applicable to operating belt tensions exceeding 439 N/mm (2,500 lb./in.). This paper examines the application of CEMA standard pulleys, T-section pulleys and also a mining duty pulley design. The mining duty pulley fills the void between CEMA standard pulleys and T-section pulleys and can eliminate the high cost and long lead times associated with T-section type pulleys.

Jan 1, 1998

By S. K. Bhoumik, D. K. Sengupta, B. P. Singh

This paper deals with experimental work to improve the settling and filtration characteristics of an industrial sludge from an iron-ore mine using synthetic polymeric flocculants. The experimental work consisted of the characterization and evaluation of suitable flocculants to enhance settling and filtration rates. The optimum dosage of the flocculants were determined. The experimental results revealed that the settling rate can be increased many times, compared to untreated sludge, by using a suitable combination of flocculants. Compared to cationic and nonionic flocculants, anionic flocculants were found to be more efficient in sludge flocculation. The synergistic effect of two anionic flocculants produced the best settling conditions. Filtration test results also reveal that suitable flocculants can improve the dewatering characteristics of the slurry.

Jan 1, 1997

By C. E. Zebula, F. F. Aplan, R. S. Datta

The hydrophobicity of oil shale was found to follow the sequence R-5 > Mahogany >> Eastern. Further, hydrophobicity was found to correlate with the total organic carbon (TOG) content, decreasing with increasing specific gravity of raw oil shale pieces. Differences in hydrophobicity from piece to piece indicate that gravity preconcentration would be much more effective for Western than for Eastern oil shales. Purified kerogen concentrates and low specific gravity fractions (<2.0) of raw Western oil shale samples show critical surface tension of wetting values of [y]c = ~35 mNm -1, and for a kerogen concentrate from an Eastern oil shale [y]c = ~46 mNm-l. This infers that dust from oil shale mining operations can be suppressed by surfactant solutions similar to those used to suppress coal dust.

Jan 1, 1988

By I. K. Kapageridis

Environmental management and planning requires the integration of large volumes of disparate information from many sources and the analysis of this information with efficient tools for assessment and evaluation. Effective methods of communication that allow interactive participation in the planning, assessment and decision-making processes are also very important. The VULCAN software package from Maptek (Pty) Ltd comprises a large number of 3D graphical tools within an interactive 3D interface called ENVISAGE. These tools are designed and developed to help engineers and scientists to identify and solve environmental problems. The combination of VULCAN 3D Software and the I-SiTE 3D Laser Imaging system leads to powerful solutions for environmental management. This paper presents the capabilities of this integrated system and its applications for environmental management.

Jan 1, 2002

By D. W. Hill

By seeking to define the social and political parameters of both established and potential uses of the underground, this paper will attempt to formulate and state the problem posed in the realms of public choice for obtaining more rapid development and more beneficial use of the underground environments. Essentially, the paper will pursue the following outline: 1. Established policies and established uses of the underground 2. Potential uses of the underground for social benefit 3. Constraints on development and policy a. Psychological constraints b. R & D plus physical constraints c. Economic constraints d. Public choice and policy contraints (both governmental and non-governmental) e. Legal and other structural constraints 4. Defining the problem from the social standpoint 5. Suggestions for surmounting the constraints and meeting the problem: some hypotheses for the future.

Jan 1, 1974

By J. Herbst, H. B. Treweek, V. R. Degner, G. Poling

Current mineral industry trends toward handling the high tonnages of lower grade ore and tailings retreat lead to a continuing need for large volume flotation cells. The benefits which accompany the larger cell flotation circuit include reduced capital cost, less mill floor space, reduced operational complexity, and less maintenance, provided the metallurgical performance and solids suspension capability of the cell are not compromised. This study reviews development considerations pertinent to large mechanical air induction type flotation cells from the standpoint of cell internal hydrodynamic characteristics and metallurgical performance. While the importance of process related factors such as chemical usage, pH control, solids size and loading, and circuit arrangement cannot be denied, this study will emphasize the relationship of cell size (volume), mechanism geometry (impeller diameter), and mechanism operating conditions (rotor speed and submergence), to air transfer, liquid circulation, liquid "rise velocity" and mechanism power draw. Specific hydraulic performance maps for large capacity 300 and 500 cu ft flotation cells will be reviewed in terms of the relationship between the operational variables and the air and liquid flow conditions within the cell. Metallurgical results, obtained under plant operating conditions for 300 and 500 cu ft cells, are included to illustrate the metallurgical performance similarity of flotation cells which follow hydrodynamic scale-up criteria set forth in this investigation.

Jan 1, 1976

By P. Raffinot, C. H. G. Bushell, S. Hodgson, E. F. Milner, H. J. Bosshardt, N. Draper, D. E. Pickett, Edwin T. McKnight, J. Prieto

Zinc ranks third and lead fourth in world nonferrous metal conumption. In 1972 the free world consumed 3,333,000 mt of refined lead and 4,422,000 mt of refined zinc. The lead tonnage was divided into the following end uses: storage batteries (42%), lead allows (7%), pigments and chemicals (11%), cable sheathing (9%), gasoline additives (13%), pipes and sheets (8%), and miscellaneous uses (10%). The corresponding distribution of zinc uses in 1972 was galvanizing (39%), die casting (26%), brass (15%), rolled zinc (8%), oxide excluding American Process zinc made directly from concentrate (6%), and other uses (6%). The pattern of usage of lead and zinc varies considerably from country to country. During 1972 in the USA 49% of refined lead was consumed in storage batteries, 19% in gasoline additives, and only 3% in cable sheathing, whereas in the United Kingdom 28% of the lead was consumed in batteries, 14% in cable sheathing, and 14% in gasoline additives. For zinc the major US uses were die casting (41%) and galvanizing (37%), with about 3% consumed as rolled zinc; corresponding usages in the same applications in France were 12, 28 and 28% and in Australia 12, 67, and 3%, respectively. The outstanding resistance of lead to corrosion, its density, and

Jan 1, 1985

By Raymond E. Riethmann

El clasificador de espiral fue diseñado originalmente para circuitos cerrados de molienda. Desde entonces se ha aplicado con éxito a otros trabajos de clasificaci6n donde se necesita realizar un corte de dos productos. Inherentemente a las cualidades especiales de este cla- sificador está especialmente preparado para: clasificar, lavar, o agotar materiales tales como minerales, roca fosfática, arenas, carbbn, conchas de ostra y sales fosfáticas. Presentamos ahora las características de operation, flexibilidad de diseiio y líneas maestras para una apropiada aplicación.

Jan 1, 1982

By Steve Lloyd, Mary Anne Antonioli, Byron Darnton

Pegasus Gold Corporations' Montana Tunnels mine began oper­ation in March 1987. The process plant at startup consisted of a bulk flotation circuit followed by leaching of the reground bulk concentrate. The leach residue then advanced to selective Pb/Zn flotation. This original circuit had its share of problems, and the leach circuit was abandoned after six months. The bulk flotation circuit was modified to selective Pb/Zn flotation at this same time. Gravity concentration was researched early on, prior to selecting bulk flotation with leach as the flowsheet of choice. Flotation was deemed to be more practical than gravity due to the lower capital and operating costs. No further work was done concerning gravity concentration until 1990 when it was decid­ed to investigate ways to diminish the occurrence of free gold reporting to the flotation tailings.

Jan 1, 1996

By G. Orhan, C. Arslan

The possibility of producing metallic chromium from Cr2O3 via the aluminothermic route, with no external energy supply, was the subject of this laboratory-scale research. The experimental study focused on investigating the individual effects and quantitative optimization of the charge contents, i.e., the additions of CrO3, Al powder and CaO (or BaO). The highest chromium recovery of 98% was attained with the additions of 12% CrO3 and 1.2 times the stoichiometrically required amount of Al powder. The optimum CaO addition giving the highest chromium recovery was found when the CaO/Al weight ratio in the charge was equal to 0.3. When BaO was used, however, 95% Cr extraction efficiency was obtained at a BaO/Al weight ratio of 0.15.

Jan 1, 2000

By P. Ollivier

A comparative study on potential refractory ore processing techniques was launched at the BRGM to enable exploitation of numerous small deposits of arsenopyrite and antimony sulphide ores.

Jan 1, 1998

By Otis M. Clarke

Domestic bauxite used in aluminum production comes from Arkansas where syenite was lateritized forming bauxite. Part of the residual bauxite and kaolinized syenite were eroded, deposited downdip, lateritized with bauxite formed in place, and covered by sediments. The unconsolidated overburden causes problems in mining. Bauxite for refractories and chemicals comes from Alabama and Georgia. Sediments were deposited in karst lakes and were lateritized forming bauxite and kaolin. Ferruginous bauxite in Washington, Oregon and Hawaii, derived from weathered basalt, can be used in aluminum production.

Jan 1, 1984

By Ross W. Smith, Xiapeng Zheng, Peggy J. Arps

The adhesion (and de-adhesion) of Bacillus subtilis to dolomite was determined under a number of conditions of initial concentration of the organism, agitation, mineral particle size and temperature. Rate equations curves for both adhesion and de-adhesion were constructed, with the rates of de-adhesion being about half that of adhesion. From the temperature data the energy of adhesion was determined to be about 1.02 kcal/mol. Adhesion of dolomite to B. subtilis follows a Langmuir isotherm. Equilibrium constants, adhesion capacity and Gibbs free energy of adhesion of B. subtilis to dolomite (at pH 6.6) were determined. These values were compared to similar data for adhesion of B. subtilis to apatite and dolomite.

Jan 1, 2002

By R. J. Pugh

The surface chemical sites on several fillers (quartz, feldspar, calcite and granite) were studied by the adsorption of well defined acid and basic probe molecules (benzoic acid, benzyl alcohol, ethyl benzoate, pyridine and benzyl amine) from cyclohexane. The results provided a wide variation of adsorption data, emphasizing the extensive range of site heterogeneity on the filler surfaces. In addition, it was shown that the acidic probes were strongly adsorbed on all of the minerals, thus indicating that the basic surface sites dominate the acidic ones. Also, through FTIR studies with vapor-phase probes adsorbed on orthoclase, it was possible to identify the nature of specific sites and the type of bonding occurring between the filler surface and the probe molecule. These types of surface analytical techniques could give useful information for predicting the adsorption functional groups on dispersants, dyes, thickeners, etc. and could lead to enhanced interfacial bonding between the filler and the matrix.

Jan 1, 1993

By Eric Forssberg, Benny Andreasson

The paper describes experiments to stabilize mineral processing waste materials for use in construction. Fine mineral processing wastes from various mines have been mixed with binders and compacted. As binders blast furnace slag and other materials have been used. Experiments have been made in laboratory scale and in large scale. The results have been evaluated by means of determinations of compression strength and the modulus of elasticity. The paper also describes some experiments in laboratory and large scale to use stabilized mineral processing wastes for back filling in cut and fill mining.

Jan 1, 1992

By Stanislaw Wasilewski, Zdzislaw Krzystanek

Ventilation process in deep mines features relatively low efficiency. Commonly used passive control by means of regulators and flow throttling leads to remarkable energy losses that could be lower if effective monitoring and remote control of main fan operating point were implemented. In the paper, some results of investigation carried out in Polish coal mines to evaluate real energy losses in ventilation process are described. Different methods for main fans performance monitoring and control are considered and compared especially those using fan drive speed control to minimize power consumption. On the other hand some criteria for power evaluation are analysed and algorithms for optimum location of controllers in ventilation network are considered. The results of investigation are being implemented in the first system for monitoring and control of main fan operating point in Miechowice colliery.

Jan 1, 1995

By J. Hanna, J. Jung, I. J. Anazia

Electrothermal production of elemental phosphorous (P4) generates substantial amounts of highly toxic phossy water and sludges. Because of their high phosphorous contents and lack of reliable processing technology, large tonnages of these hazardous wastes have accumulated from current and past operations. To date, the sludges are stored in ponds or above ground in special containment vessels at various locations around the country. Two samples of electric furnace phosphorous sludge (obtained from the Tennessee Valley Authority (TVA) in Muscle Shoals, AL and FMC Corporation in Pocatello, ID) were investigated using physical separation techniques to recover the elemental phosphorous and to render the residual material nonhazardous. The techniques tested include sizing, froth flotation and dispersed air oxidation. Flotation and sizing produced concentrates containing 69% - 90%P4, with recovery in the range of 60% - 87%. Dispersed air oxidation of the fines and tailings products was effective in the removal of an additional 10% - 15% of the P4 in the sludge.

Jan 1, 1993

By S. Zaman, F. F. Aplan, Franklin T. Davis

This section deals with the oxides of heavy metals, namely, columbium and tantalum, rare earths, chrome, manganese, titanium, tin, and tungsten. Table I contains the production figures for each of these commodities in the US and in the world in 1977. Specifications for concentrates are also summarized as well as prices for concentrates in 1977. In each chapter an attempt has been made to describe the more common commercial mineral involved with the commodity and the processes used to recover and concentrate the minerals, as well as geographical areas where these processes are utilized.

Jan 1, 1985