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By Drew F. Holbrook

Most of the siliceous rocks of the Arkansas Novaculite are novaculite, but they also include some chert, siliceous shale and, rarely, sandstone. Novaculite is defined as a homogeneous mostly white or light-colored rock, translucent on thin edges, with a dull to waxy Juster, and comprised almost entirely of microcrystalline quartz. The most plausible theory of origin for novaculite is that primary silica from submarine volcanism was picked up by organisms and deposited as amorphous silica, which was subsequently converted to microcrystalline quartz (novaculite) through diagenesis. The Arkansas Novaculite crops out over an east-west distance of 200 miles in the Ouachita Mountains of Arkansas and Oklahoma. Three divisions of the formation have been defined: a Lower Division, almost entirely massive light-colored novaculite; a Middle Division of interbedded dark chert and shale; and an Upper Division of massive calcareous novaculite. The Lower Division and most of the Middle Division are Devonian in age, and the remainder of the Middle Division and all of the Upper Division are Mississippian. The massive novaculites of the Upper and Lower Division attain their maximum development along the southern and central outcrop belts of the formation in Arkansas, and it is these rocks that are the source of current silica production. The calcareous novaculite of the Upper Division weathers readily to a light-colored, porous, less brittle rock, and in places to tripoli deposits. Currently tripoli is mined from a single deposit near. Hot Springs, Arkansas, and the rock is processed for highly specialized filler and abrasive applications. In the vicinity of Hot Springs, Arkansas, certain novaculite layers from the Lower Division with unique textural characteristics are quarried and processed into whetstones. Several small quarries produce this rock for two local and one out-of-state whetstone-fabricating plants. Chemical analyses of composite samples of novaculite from both the Upper and Lower Divisions taken at widely separated localities average 99 percent SiOz indicating a substantial resource of high-silica rock.

Jan 1, 1978

By S. G. Mougiakakou

A computerized system (SCAPEVIEWER) based on landscape indices and artificial intelligence techniques is proposed in order to classify landscape images into various categories according to the quality of the pictured scenery. Photographs (totally 108) from various landscapes have been clustered, from seven experts in accordance to the mean estimation of landscape quality, into distinctive (C1), typical or common (C2), and indistinctive (C3). For each of the landscape photographs, ten (10) environmental and operational indices have been selected and determined, corresponding to visibility (V), naturalness (N), relief (R), flora quantity (FC), flora quality (F), water (W), skyline (SL), visual entities (G), season (S), and viewer position (P). These landscape indices are fed to a classifier. The classifier is a feed forward Neural Network (NN) trained by a novel hybrid method combining genetic algorithms and the back-propagation algorithm with adaptive learning rate and momentum. A total classification rate of 93.5% has been achieved, using only 8 input neurons. The discarded input neurons correspond to the indices S, and P. The pilot system SCAPEVIEVER has shown the feasibility of landscape photograph classification into three categories (C1, C2, and C3) according to the landscape quality, selecting simultaneously the most robust indices, by means of a computerized system combining the knowledge of an expert with a NN based classifier.

Jan 1, 2003

By Anna Marabini

This paper provides a summary of the studies performed over a period of more than fifteen years by the Italian National Research Council's Mineral Processing Institute in Rome to develop applications for the use of chelating reagents in the flotation of metallic minerals. A description is given of the various phases through which the studied progressed, starting with the combined use of commercial chelating reagents and a neutral oil and then moving on to the synthesis of new long-chain chelate collectors for the flotation of sulphide and oxidized Pb, Zn and Cu minerals. After a series of preliminary tests which confirmed the possibility of floating various metallic minerals with commercial reagents containing chelating groups exerting specific action on given cations, the studies were addressed to the development of a theoretical method of choosing chelating groups that exert selective action on one metallic mineral rather than others. The theoretical approach was based on thermodynamic data concerning the chemical equilibria in solution. The validity of the method has been proved in numerous cases by flotation tests on pure minerals. Subsequently the research was directed towards the design and synthesis of reagents with a mixed aliphatic-aromatic structure containing chelating groups for Pb and Zn and an alcoxyl chain of various length, position and configuration. The flotation results obtained on oxidized and mixed Zn-Pb ores provided interesting pointers for designing the nonpolar portion. The structural criteria identified via these studies were interpreted on the basis of chemical and steric considerations. A description is given of a new synthetic chelate collector which is effective in the selective flotation of Cu minerals from complex sulphides. The fact that this reagents is more selective than xanthate is demonstrated by comparative flotation tests on actual ores.

Jan 1, 1994

By D. A. Norrgran, J. N. Orlich

Described is the application of high- intensity magnetic separation throughout the spectrum of industrial minerals. Performed either wet or dry, the separation has application in both the recovery and concentration of value minerals and in removing deleterious mineral constituents. The various types of magnetic separators along with the design and operating parameters relative to separation response are characterized. The characteristics of specific minerals to magnetic collection and the production of high-grade concentrates are described. Laboratory, pilot-scale, and plant studies carried out on a variety of industrial minerals have demonstrated the effectiveness of magnetic separation as either a primary or a secondary unit operation to achieve product quality.

Jan 1, 1987

By G. Rinelli, Arthur F. Colombo, Donald W. Frommer

With the opening of the Tilden mine near Ishpeming, MI, a new era in iron ore beneficiation was begun. A description of a U. S. Bureau of Mines investigation is summarized to illustrate the selective flocculation-deslime-flotation process developed by the Bureau and used at the Tilden concentrator, which is also briefly described. The operating parameters for the selective flocculation-cationic flotation of an oxidized taconite from the Mesabi range are discussed. A water reclamation system using lime and a cationic flocculant was applied to reclaim the effluents from a 900-pound-per-hour flotation pilot plant. About 80 percent of water requirements were recovered, and the calcium content of the reclaimed water was found to be more important than clarity in influencing the selective flocculation and flotation processes. Although reclaimed waters with about 10 ppm calcium registered turbidities of approximately 5,000 ppm SiO2 equivalents, the concentrates produced using these waters contained 64 percent Fe and =5.0 percent SiO2 and had accompanying iron recoveries of 75 percent. Lower grade concentrates resulted from using reclaimed water with higher calcium contents and lower turbidities.

Jan 1, 1976

By Leo Misagi

THE ROLE OF MANAGEMENT IN PLANT SAFETY Safe Production In plant management, safe production is an ideal. It becomes reality when: 1. Plant employees work in healthful and safe conditions. 2. Plant safety is in harmony with productivity. 3. Worker absenteeism and turnover are low-the work force is stable. Plant management must apply its talents, skills, and resources to build and maintain the foundations of safe production on a system of policies, procedures, and attitudes. It must do so by marshaling all managerial functions - staffing, direction, control, innovation, and representation-toward that goal. Ideally, a plant safety program is proactive. Management should plan and implement safety activities that are aimed at prevention. Past accidents-accomplished facts-should not be the sole guide of future actions. In other words, positive preventive measures, not the fewness of accidents are the criteria for safety production. An ideal safety program is one which is cost effective. Management should view plant safety as part of a broader program-loss control. Loss control includes prevention of fires and other accidents, unhealthful conditions, and occurrences that cause bodily injury, illness, property loss, or damage. Management evaluates the employees' productivity and safety. An effective training program aimed at loss control is the hallmark of safe production. Ideally, both labor and management should be well versed in safety. They believe in the premise that work-related injury and illness, as well as property loss and damage from fire and other accidents, are manageable and preventable. Such belief prompts them to learn more about the work process and potential hazards associated with each job. They also learn how to expect and prevent fues and other accidents, and respond to emergencies at the plant. Plant management determines which individuals or groups of employees are accountable for the following functions:

Jan 1, 1991

By Ronald E. Yarbrough, Theodore L. Triplett, Larry R. Powell

The Bureau of Mines, in cooperation with the Illinois Mine Subsidence Insurance Fund, is monitoring the response of two foundations to ground movements induced by subsidence from a high-extraction retreat room-and-pillar operation in southern Illinois. The objective of this monitoring program is to study the inter- action between the ground surface and a structure during a subsidence event. Data from such a study should enhance the understanding of the mechanisms that produce structural damage and aid in the design of structures that resist such damage. This paper describes the monitoring instrumentation and techniques as they relate to the mining and site conditions. The capability of a tiltmeter to detect and follow the tilt of the foundations caused by the mining subsidence sequence is demonstrated. Using data from this tiltmeter, the development of curvature in the foundations as they conformed to the displaced ground surface is shown. This curvature is rep- resented by differences in tilt at various points on the foundations, indicating a change in tilt over a horizontal distance. Also, even though subsidence damage has not been fully analyzed, preliminary observations of the cracks that formed in the foundations are reported. These cracks resulted in the separation of one footing into distinct pieces; therefore, their effect on the tilt readings is cited.

Jan 1, 1986

By Angus Campbell, Michael J. Gobla

Numerous techniques for treating, controlling, and preventing acid rock drainage have been applied at the Summitville Mine Superfund Site. Challenging aspects of the remote mine site include the wide-spread occurrence of acid-generating soils and rocks, extensive surface and underground mine workings, and a cold and wet climate. Water treatment was an immediate necessity when the Government took control of the abandoned site in December of 1992. Subsequent reclamation activities have emphasized prevention and control of ARD to minimize future water treatment requirements. A combination of conventional, innovative, and experimental methods are being applied to successfully mitigate ARD at Summitville.

Jan 1, 2000

By M. J. Virnig, Marc Le Vier, Rong Yu Wan, Jan D. Miller

Although most gold production from primary resources is achieved by cyanidation, many research activities have focused on alternative processes using noncyanide lixiviants. Such research has been prompted by environmental concerns and problems associated with the processing of refractory gold ores. Numerous research projects have been conducted to search for a noncyanide hydrometallurgical process for gold extraction. In this paper, a technical review of gold recovery from noncyanide solutions is presented, and new results are reported. Gold recovery techniques that are considered include activated carbon adsorption, cementation, solvent extraction, ion exchange, and reduction-precipitation.

Jan 1, 1993

By Norman Weiss

The purpose of this paper is to relate progress in the engineering field called Minerals Beneficiation to undergraduate and graduate education in our colleges and universities. So mach has been written recently about the education of scientists and engineers that I've had to struggle against the temptation to repeat what has been often said before, particularly because man like Robert Mehl of Carnegie Tech, Antoine Gaudin of MIT, H. M. Davis of Penn State, and John Vanderwilt of Colorado School of Mines have recently written many quotable paragraphs on the subject. In the matter of progress, the rapidity of proliferation in the area of physical and chemical beneficiation is convincing proof that this is indeed a lively art, and having been a millman for 35 uninterrupted years I prefer to lean on personal observations to some extent, rather than on statistics and charts v culled from the journals. I propose in this paper to talk first about the progress we've made in our branch of the mining industry in the last 3 decades--particularly in the last few years--and try to show that future progress will depend upon the quality of education and capacity for research possessed by our colleges. The second part will deal with some of the problems the colleges encounter in trying to fulfill these responsibilities.

Jan 1, 1959

By L. Shwydiuk, A. Chrzanowski, W. Newcomen, G. Bastin, R. Wilkins

Automated monitoring of steep embankments allows the early detection of instability and can be used to avoid or mitigate possible slope failures. A system that uses multiple and different types of sensors has been created and successfully tested at the Highland Valley Copper mine in British Columbia. The system uses robotic total stations (RTSs) as the primary measurement sensor, with surveys repeated at predefined intervals selected to optimize operational efficiency. A methodology has been developed to improve the system’s accuracy and reliability by reducing the effects of systematic errors created by atmospheric refraction and unstable instrument and reference point positions. The inclusion of GPS sensors to monitor the RTS positions creates additional operational flexibility and maintains system integrity when insufficient reference stations are available.

Jan 1, 2003

ABB Industrial Systems is one of the largest electrical engineering companies in the world. ABB develops, manufactures and markets electric drives. The company has more than 100 years experience in the application of medium- and high-voltage AC machines. And ABB's continuous research and development program ensures that its machines use the latest technologies and materials. Each motor is custom designed to meet specific applications. The HXR high-efficiency motors (100 to 1,900 kW or 134 to 2,250 hp at 50 Hz) are efficient and have low noise levels. Typical applications are pumps, fans, blowers, compressors and pulverizers. The enclosed units are constructed with external cooling ribs and fans. And the motors are equipped with solid, longlife stators and rigid rotor construction. The patented rotor construction provides for low vibration levels. ABB's large synchronous motors (1 to 50 MW or 1,340 to 70,000 hp up to 900 rpm) are used in the mining industry for crushing, grinding hoisting and conveying systems. These motors are designed to customer's specifications, including existing foundations. They can be equipped with fixed or adjustable speed control.

Jan 1, 1998

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there .is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages.

Jan 1, 1981

By G. Kritikakis

Rehabilitation of sites contaminated by oil products and chlorinated organic compounds is a costly task which affects the planning of urban and infrastructure development. An integrated approach based on the non-invasive geophysical technology is utilized for subsurface characterization of contaminated land. In this approach the localized information, provided by chemical analysis of soil samples collected from bore-holes, is used for the calibration of the geophysical data. This information is subsequently extrapolated to the area under investigation by combining it with the geophysical results, providing thus information about pollution accumulation, contaminants? flow and pollution sources. Two case studies are presented from sites contaminated by heavy metals (Venice, Italy) and oil products (Athens, Greece). Resistivity, electromagnetic and seismic methods were used in this approach. Namely, electrical tomography, electromagnetic mapping, ground penetrating radar (GPR), multichannel analysis of surface waves (MASW) and seismic refraction experiments were conducted. In Italy, the sections from the multichannel analysis of surface waves imaged successfully a buried channel where the pollution is concentrated. Preliminary results are also discussed from the geophysical survey in Greece where the thickness of the oil phase located on top of the water layer is 60 cm.

Jan 1, 2006

By C. W. Matthews

Introduction Screening is an art, one of the oldest in the process field today, and one of the most widely used in our present age. Screening is being applied to an ever-increasing number of assignments, in an ever-expanding circle of industries. Screening is defined precisely as a mechanical process which accomplishes a separation of particles on the basis of size and their acceptance or rejection by a screening surface. Particles are presented to apertures in a screening surface and rejected if larger than the opening, or accepted and passed through if smaller. Screens are machines with screening surfaces used to classify materials by size. The screening surface is the medium containing the apertures for the passage of the undersize material. Screens are put to many uses - size separation, dewatering, desliming, media recovery, scalping, trash removal, washing, dedusting, conveying, concentration, and many combinations of these functions. It is interesting to note that screens are used for handling commodities

Jan 1, 1985

By M. Poulton

Backpropagation, learning vector quantization, counterpropagation, functional link, probabilistic, and. self -organizing map are among the most popular neural network classification paradigms. Each paradigm finds a unique set of weights that will map the input pixels into their respective output classes. The usefulness of each network depends on its overall accuracy, ease of use, speed and scaling. The fastest and most accurate networks in this study were the functional link and counterpropagation. These networks, however, do not scale well to large input vectors or large training sets. A better choice is the LVQ network which achieves high accuracy, is fast, requires a minimum number of input parameters and presents fewer scaling problems.

Jan 1, 1992

By S. Srinivasan

Traditional pit optimization techniques cannot take account of the requirement to blend ore in order to produce a saleable product, as is the case for iron ore, coal, limestone and other industrial minerals. Various techniques are proposed to overcome the deficiencies, many of which have been tested. The techniques in general involve the combined application of pit optimization and blend optimization techniques.

Jan 1, 1996

By Edward D. Elkins

CalMat Co. is one of the largest producers of construction aggregates in the United States. The CalMat Reliance plant is located in Irwindale, California, and is situated on an alluvial fan formed by the San Gabriel River. The fan deposits are of Quaternary age and were derived from granitic and metamorphic bedrock exposed in the San Gabriel Mountains to the north. The sediments are poorly sorted and range in size from large boulders to clay size particles. The coarse material is hard and durable and consists of quartz diorite, granodiorite, granitic gneiss, schist and minor amounts of volcanic rock. The matrix is comprised of silty sand with varying amounts of clay. Thin silt and clay lenses occur sporadically throughout the deposit. The clay content of the matrix and the degree of weathering of the coarse material increases with depth. Based on seismic data, the alluvial fan varies from 200 to 400 feet thick and overlies crystalline bedrock. The Reliance plant was constructed in 1971 and 1972. It has a nominal capacity of 1200 to 1400 tons per hour, and typically produces more than three million tons of aggregate products per year. Alluvial fan sediments are mined from a gravel pit situated adjacent to the plant. The material is fed through a mobile, 48- by 60-inch, in-pit jaw crusher, then transported by conveyor to the main plant to be processed. The plant is modern and highly efficient. It has a typical wet and dry circuit and is capable of producing a wide range of aggregate products. To extend the life of the plant, a 9,000 foot conveyor system is being constructed to connect it to a granite quarry operated by Azusa Rock Inc. The quarry is located north of Irwindale, and is 50 percent owned by CalMat Co. The conveyor will be used to export crushed rock from the quarry to Reliance. The existing plant will be modified to process the crushed rock.

Jan 1, 1995

By Bryce Sullivan, Cliff Baratta, Ehsan Alavi, Timothy Dobbs, Lisa Mori

"Soil conditioning is one of the main factors in successful application of EPB machines in tunneling projects, which involves changing the characteristics of the ground in order to make it suitable for the tunneling process. Selection of the type of conditioner mainly depends on soil type, properties of the tunnel boring machine, and most importantly geological condition. Proper EPB tunneling and soil conditioning in ground above water table is challenging. This was encountered in Northgate Link Extension Tunneling Project in Seattle, WA. In order to improve the tunneling operation, a novel algae-based encapsulated oil was used as a conditioner and as a result the operation of the TBM was improved significantly. This paper reviews the traditional soil conditioning measures that were adopted in University Link and Northgate Link projects in Seattle, WA and compares the results with results when using the encapsulated oil additive. INTRODUCTION Soil conditioning agents are used in EPB tunneling to transform the excavated soil into a workable paste with the desired hydrological and mechanical properties. Reducing wear, power consumption, friction, adhesion, and improving the face stability and material flow are some of the benefits of using soil conditioners in EPB tunneling. Soil conditioning is performed by injecting foam, polymer, water, and bentonite to the tunnel face, excavation chamber and screw conveyor. Selection of conditioning agent mainly depends on soil type, geological condition (groundwater and soil permeability) and TBM features (injection points, open or closed cutterhead, type of foam generator, etc). The most widely used soil conditioners are foam and polymer and in some cases due to existing conditions, clay dispersion or anti-wear additives are also used (Milligan 2000, Langmaack 2000). Foam. Foam is created by dispersing air in a surfactant solution. A different combination of surfactant type and foam parameters should be used for different soil types. Laboratory tests on virgin soil should be performed to identify the best surfactant and foam parameters for the specific soil type (Langmaack 2000). The foam parameters can be described as follows:"

Jan 1, 2016

By David R. Klug, Chris Gause, Troy L. Page

The Inter-Island Tunnel is one of two undersea tunnels which are part of the Boston Harbor Clean-Up Program. The tunnel is 7.7 km (25,160 ft) long, bored to a 4.3 m (14 ft) diameter in the Cambridge Argillite Formation and was finished to a 3.5 m (11.5 ft) diameter final concrete lining. The owner is the Massachusetts Water Resources Authority (MWRA) who is a regional authority responsible for overall design and construction. The tunnel's primary purpose is the transport of untreated effluent from Nut Island facility in Quincy, MA to the new treatment plant at Deer Island. Two sludge lines are installed for the transport of sludge from Deer Island to Nut Island. During construction the contractor encountered fault zones, fractured strata, and soft ground tunnel sections which liberated more ground water than was originally anticipated by the project designer. Ground water was controlled during mining and the placing of the final lining. The final lining of cast-in-place concrete had to be backfill grouted to cut off water inflows and provide contact for equal tunnel loading which is critical in long-term design. This paper deals with an engineered backfill grouting system which was the first of its type to be used in North America. It discusses the geological conditions encountered, the design criteria used in the evaluation process, and an indepth review of the various system components. It demonstrates how contractors can use knowledgeable and professional industry suppliers to solve difficult construction problems.

Jan 1, 1999