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By F. Robert Hollo

Programmable controllers have achieved remarkable acceptance over the relatively few years since their introduction. They provide some unique advantages over conventional relay and solid-state logic, which they often replace. Programmable controllers are discussed in both conceptual and functional terms, followed by an exploration of their applicability to material handling tasks with particular emphasis on conveyor systems.

Jan 1, 1973

By John J. Sammarco

Abstract- Emergency shutdown systems (ESDs) for mining machinery provide critical functions to safeguard miners. Traditionally, ESDs were realized with simple hardwired circuits; today, there is a growing trend to use programmable electronic technology such as programmable logic controllers (PLCs). This paper describes an analytical study to quantify the safety integrity of a PLC-based ESD and a hardwired ESD. The safety integrity level of each design approach was determined by quantifying the average probability of failure on demand (PFDavg) as described by the recommendations for programmable electronic mining systems published by NIOSH and the IEC 61508 international standard. The safety analyses addressed system architecture, hardware failure probability, proof test interval, diagnostic coverage, and human error probability. The results indicated that a same level of safety, safety integrity level 3 (SIL 3), could be attained when evaluating random hardware failures. Neither approach could attain SIL 3 if manual activation was used. Human error was the limiting factor where, using human reliability analysis, PFDavg < 1 x 10-1; thus, the ESD does not meet SIL 1. It is apparent that automatic verses human¬activation of the ESD is a very important safety consideration. Manually actuated ESDs can only achieve SIL 1 regardless of the technology; therefore, additional independent safety layers of protection are needed to exceed SIL 1. Secondly, it is apparent that the technology choice is very important. The PLC-based ESD was much simpler to design and to validate safety1.

Jan 1, 2007

By L. W. Krahenbil

The programmable Logic Controller (PLC), at its present stage of evolution, is now considered as a mature control system. The PLC combines the solid-state reliability of hardwired logic and computer control systems with the simplicity of a relay ladder logic. Relay symbolic programming through a function-oriented keyboard provides a means which plant personnel can easily become accustomed to work with. In a large coal facility, it is shown that the control engineer can provide improved control flexibility with the advanced capabilities of the PLC.

Jan 1, 1979

By Jean-Luc Cornet

As modern conveyors are increasing in size and complexity, their control requirements are becoming more and more critical. In addition to the safety and equipment protection requirements, control systems are now called to implement intelligent drive controls derived from dynamic analysis modelling, as well as to provide fast and accurate diagnostics while keeping operator controls simple. These requirements led to the development of a new and innovative approach to control system development. This paper describes the control philosophy used by Conveyor Dynamics, Inc. (CDI) and some of the key features of our approach to the architecture of control systems.

Jan 1, 1993

By Mike Horn, Keith Meade, Marvin L. Smallwood

Technological changes in programmable logic controllers (PLC)&apos;s and the need to improve the architecture of Mine Wide Monitoring Systems (MWMS) has resulted in the design of a PLC based system at the Virginia Division of Island Creek Coal Company. The system which is presently in the installation phase, is a joint effort of Island Creek Coal Company, Westinghouse Electric Supply Company and Mining Controls Incorporated. The system uses an ethernet based network for graphic display of system data operating under the Genesis software package. Telemetry for the system utilizes the Seimens/Westinghouse L1 network operating over two twisted pairs. Remote telemetry uses fiber optic links and modems operating over standard telephone lines. 500 and 2000 series PLC&apos;s provide distributed data processing for the system with hierarchial processing operating under the Genesis software on the ethernet network for individual mine site monitoring along with the remotely located division office monitoring. System control and data acquisition is provided for underground MWMS operations and on the surface for a vast methane gathering system that is used for degasification of the mines and collection of pure methane for sale to the Columbia Gas Company as natural gas. The inability of industrial MWMS companies to keep up with the vast changes in technology, along with economic considerations associated with expanding the existing MWMS created the need for the development of the PLC based system to replace the older industrial monitoring systems.

Jan 1, 1993

By Robert G. Paul

President Reagan&apos;s Exclusive Economic Zone (EEZ) Proclamation of March 10, 1983, extended United States ocean jurisdiction 200 nautical miles offshore our coastal states and territories. The accompanying policy statement noted that this action was a result of recently discovered deposits of polymetallic sulfides and cobalt-rich manganese crusts, which could be a major source of minerals important to the U.S. economy and security. Within these 3 billion acres of exclusive economic jurisdiction, the United States has sovereign rights to explore, develop, conserve, and manage the mineral and other natural resources of the seabed. The President has directed the Department of the Interior (DOI) to encourage exploration and production of minerals from this area. The DOI, through the Minerals Managment Service (MMS), is responding to this presidential directive by developing a leasing program for nonenergy minerals in the EEZ. The authority to develop this leasing program is the Outer Continental Shelf Lands Act of 1953, as amended in 1978, which authorizes the Secretary of the Interior to grant leases for oil, gas, sulfur, and other mineral resources on the Outer Continental Shelf (OCS). The Solicitor of D01 has determined that the definition of the OCS for legal purposes extends at least 200 nautical miles offshore of our coastal states to the EEZ boundary. Section 8 (k) of the Act allows the Secretary to lease minerals, other than oil, gas, and sulfur, on the basis of competitive bonus bidding and under such terms and conditions as he may prescribe at the time of offering the area for lease.

Jan 1, 1985

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

In 1973, US Borax & Chemical Corp. began investing three days wages and about $20 in training materials in every new employee before having him report to his first job. The result? Accidents involving new employees in the past two years have dropped by more than half from the 1972 level. What made this success possible was safety training done with programmed instruction materials-which, incidentally, US Borax also uses for vocational training.

Jan 4, 1976

By C. S. Gibson

INTRODUCTION I WELCOME the opportunity to speak on Programmes in Safety. The invitation to do so shows that those guiding affairs of the Institute in this District realize the practical importance of this subject. My remarks are intended primarily for mines having 100 to 400 employees, approximately. With minor modifications, however, they apply also to larger or smaller operations. Others, I hope, will derive benefit from this paper, for they, too, have a part to play in accident prevention; for example, contractors such as shaft-sinkers; manufacturers of equipment; and consultants and designers of mining, milling, and metallurgical methods. These troubled times stress, as never before, the importance of efficient operations in mining. The days are gone when neglect can be afforded. Safe working conditions and satisfied employees are essential for efficient production at reasonable cost. The mining industry of Ontario long has been keenly aware of the human aspects of this subject, and as a whole it has done much to decrease the frequency and severity of disabling accidents. The number of fatalities per 1,000 employees has been reduced from a high of 5 some two decades ago to an all-time low of 0.89 in 1948; the incidence was slightly higher in 1949, being 1.17 per 1,000. The reduction in non-fatal compensable accidents also has been outstanding, frequency having ?been reduced from over 200 per 1,000 employees some two decades ago to 54 per 1,000 at the producing mines in 1949. These statistics demonstrate progress. Nevertheless, the general picture still leaves much to be desired when viewed from two other angles.

Jan 1, 1951

By Dilip Banerjee

"This paper discusses the Advanced Technology Program (ATP)'s support over the last decade to the development and use of process modeling as a tool to address some of the challenges faced by the U.S. metal casting industries. A particular focus will be given to highlight how process modeling can be used to improve the manufacturability of components needed for high performance and critical applications. The challenges associated with the design and production of thin-walled, cast parts with intricate and complex internal geometries will be discussed. Modeling issues associated with the control of the final grain structure in the solidified parts will also be addressed. This paper will describe the advantages of using appropriate mathematical models for designing new alloys for use in various applications.Finally, the role that ATP has played in uplifting the U.S. technological base through partnerships with industry and academia in high-risk research in order to bring to market new and improved products for the broader benefit of the nation will be discussed.ATP's BackgroundIn the 1980s, U.S. industries were losing market share to low-cost, high-quality manufacturers from Asian countries. Corporate leaders and policy makers determined that in order to sustain and grow market share, U.S. industries needed to improve their competitiveness and productivity through product and process innovation. There was evidence that companies were systematically under-investing in leading-edgetechnologies and failing to complete the development of new technologies [l]. There were also arguments in academic circles that pointed to a potential market failure in the area of early-stage technological developments. These concerns provided impetus for creation of the Advanced Technology Program (ATP) within the National Institute of Standards and Technology through the Omnibus Trade and Competitiveness Act of 1988. Through a rigorously competitive, cost-shared partnership with industry, ATP fosters the development and broad dissemination of high-risk technologies that offer the potential for significant broad-based economic benefits to the United States."

Jan 1, 2004

By Gago P. Oliver

El origen del sostenimiento con pernos para roca se remonta al inicio de la década del 70, donde el uso inicial fue a través de varillas "L"de diámetro de ranura a un extremo introducido a una cuña. El requisito para el desempeño del perno fue contar con un hueco de perforación a la medida y una roca competente para este fin. Posteirormente se realizaron otras pruebas para determinar la capacidad de anclaje de la roca encajonante como de las vetas de l/8" de diámetro con "mariposas" a un extremo como medio de anclamiento. En este sentido, el texto señala que el uso de tubos para el yacimiento de Quiruvilca es favorable, en comparación a los pernos, puesto que mejora el rendimiento y seguridad de la mina, aunque su adquisición sea costosa. Mientras que desde la perspectiva de la mecánica de rocas, el método de reforzamiento es el más efectivo ya que actúa contra la totalidad de la superficie del hueco.

Nov 8, 1984

By S. Saluja

El presente texto describe las aplicaciones de los pernos de roca como un sistema de sostenimiento en la minería. Asimismo, se comparan los distintos tipos de pernos de roca, se muestran los pernos de roca de madera y la función de los tijerales de sostenimiento en la prevención de la comba del techo.

May 1, 1981

By Mario Samamé Boggio

El presente texto señala los progresos recientes respecto de la siderurgia y la ferrominería en algunos países de América Latina. En el caso de Argentina, la vanguardia tecnológica radica en el aumento de la capacidad productiva y la tendencia hacia una aminoración en la tasa de crecimiento del consumo interno, crecimiento de la producción, exportaciones y en los problemas de abastecimiento interno y externo de chatarra y semiproductos. En el caso de Brasil, el sector de aceros tiene relevancia con la inauguración de la plan a de la empresa Acos Finos Piratini, en Río Grande do Sul. Esta cuenta con instalaciones de reducción directa, donde se utiliza carbones pobres de la misma zona y con capacidad para 65.000 t por año de fierro esponja. La industria siderúrgica de Colombia mostró en J 972 nuevos avances en sus cifras globales de producción de acero y en sus niveles de productividad. En Chile, la Compañía de Acero del Pacífico se dispone a construir una planta de peletización, que utilizará finos provenientes de sus minas de Algarrobo y Boquerón Chañar. En Ecuador, la empresa ANDEC, que está operando a un nivel de 30,000 t. anuales de laminados, definirá su programa para encarar la producción de barras en rollos y alambrón. Finalmente Perú, definió su programa de desarrollo siderúrgico, el cual contiene inversiones que para 1990 sumarán unos mil millones de dólares.

Mar 1, 1975

By William J. Bryson

Just picture, if you will, the hot, lonely and desolate Ochre Mountains west of Salt Lake City. There works a grizzled old miner, his boots worn down, his clothes hang on a body stooped by years of hard labor. His skin is wrinkled and leather toughened by many years in the hot desert sun. His ever faithful burro stands patiently in the shade of a large rock as the tired old miner examines ore samples just acquired that very morning. Suddenly the old man&apos;s eyes widen, his breathing becomes rapid. &apos;Leaping to his feet, with a gleam in his eye, he cries, "Eureka, I&apos;m rich, I&apos;ve found the mother lode. This is where I will start my digging. " Without warning, the silent wilderness is alive with wild, shouting, charging figures! Frightened the old miner glances about him wide-eyed and pan- icky. His heart sinks, dismayed he now knows all is lost, this is the end. For there leaping from behind rocks and brush papers in hand, are the men from the Department of Interior, Bureau of Land Management, State Mine Inspectors, OSHA, MESA, EPA, OEO, and the never ending list of regulatory bodies related to todays mining industry.

Jan 1, 1975

By G. H. Gronhovd

The U.S. Geological Survey estimate of the total remaining reserves of lignite in this country as of Jan. 1, 1967 was about 448 billion tons. This represents 27 percent of the total coal reserves on a tonnage basis and about 17 percent on a thermal basis. Approximately 98 percent of these reserves are in a vast lignite field located in western North Dakota and eastern Montana. This field also extends north into the Canadian province of Saskatchewan. Despite these large reserves and relative ease of mining by stripping operations, lignite production historically has accounted for less than 1 percent of the national total. This is largely due to the fact that the lignite deposits are located in an area that has no large centers of population and the economical radius of transportation is limited by its relatively high moisture and low heating value. Commercial utilization of North Dakota lignite for power production became firmly established in the mid-1920&apos;s with the development of the first successful lignite-burning equipment. Most of the early lignite-fired boilers were equipped with spreader stokers, but as the size of the plants increased, pulverized-coal firing became the more popular method, and with few exceptions, the plants built during the past 15 years are pc-fired.

Jan 1, 1968

By Arthur E. Morris

Fifty years ago when Professor Yazawa began his career, the field of process simulation and modeling was in its infancy. Since then, tremendous progress has been made in our ability to model metal production flowsheets from mine to refined metal. This progress has come about by parallel developments in basic understanding of process chemistry and in computational techniques. This paper will review the progress made in process understanding and modeling in lead, zinc, and copper metallurgy from its inception to the present, and the role of Professor Yazawa&apos;s work in furthering this progress. Specific examples wi1\ be given for the sintering of lead concentrates, slag fuming, zinc concentrate roasting, flash smelting of copper, and pyro-extraction of zinc. Factors limiting further progress will be described.

Jan 1, 2003

By Arthur E. Morris

Fifty years ago when Professor Yazawa began his career, the field of process simulation and modeling was in its infancy. Since then, tremendous progress has been made in our ability to model metal production flowsheets from mine to refined metal. This progress has come about by parallel developments in basic understanding of process chemistry and in computational techniques, This paper will review the progress made in process understanding and modeling in lead, zinc, and copper metallurgy from its inception to the present, and the role of Professor Yazawa&apos;s work in furthering this progress. Specific examples will be given for the sintering of lead concentrates, slag fuming, zinc concentrate roasting, flash smelting of copper, and pyro-extraction of zinc. Factors limiting further progress will be described.

Jan 1, 2003

By E. M. Wilde

Through the USGS&apos;s National Coal Availability program, coal resource appraisals have been completed for three 7.5-minute quadrangles (Willow Crossing, Colstrip East, Colstrip SW) in the Powder River Basin area of southeastern Montana. Available coal reserves (original reserves minus tonnages affected by current restrictions) vary from 44 to 70 percent of the original reserves. Major restrictions impacting each area also vary. In each area, one or two beds contain most of the reserves, but up to eleven beds contain available coal. The main beds in completed studies are the Knobloch, Rosebud, Sawyer and Flowers-Goodale. Three additional areas (six 7.5-minute quadrangles) are in preparation.

Jan 1, 2001

By David R. Mitchell

THIS paper is limited primarily to a description of dry coal-cleaning processes in which air currents are used to effectuate a separation between coal and refuse. Processes depending mainly on differences in the coefficient of friction, resilience and shape are not described unless the use of air is necessary for the proper functioning of the process. The air cleaning of coal is of primary importance to the coal industry of the United States. From figures presented in the 1941 edition Mechannual,1 it is estimated that at least 12 million tons of bituminous coal was cleaned in the United States during 1940 by machines using air as the separating medium. One of the current problems confronting the coal-preparation engineer is the dry cleaning of small sizes and slacks. Progress in machine development for the cleaning of small sizes has been slow in recent years in the United States of America; it has been much more rapid in Britain and on the European continent. This paper does not attempt an exhaustive survey of all these developments, and only machines and processes that have found considerable commercial application are cited. Further, no critical analysis has been made of the theory involved in the separation of coal from refuse by processes using air as the separating medium other than that necessary for an understanding of particular machine designs and applications. HISTORICAL SUMMARY The possibility of using air for the separation of coal from refuse was recognized early by mining men and many attempts were made to develop commercial machines. The ingenuity of the early experimenters is to be marveled at in view of their lack of knowledge of the theoretical principles involved. As in other arts, practice has largely preceded theory. Yet, science and practice play a game of leap frog, now one ahead, then the other; the careful experimenter governs his efforts along practical lines by adapting his experiments to the limits prescribed by scientific laws. By first studying developments and the theory involved, it is not only possible to adapt processes to new uses but also to reduce materially operating cost and to build larger units without costly failures. Although many inventors have applied for patents for separating minerals by the use of air currents, the literature in regard to coal is meager. Berrisford2 describes briefly some of the early attempts to clean coal without the use of water. Several of the examples cited by him are reproduced herein. Fig. I shows a machine used for grinding and sizing, in which rollers running in a pan with a perforated bottom and fan opening on the side crushed the coal, which was then carried by the air currents to a settling chamber. The heaviest particles dropped out first and the light ones farthest away, as shown. In the year 1864, a machine was made that could be used as a sizer or to separate dirt from coal with a sized feed (Fig. 2).

Jan 1, 1942

By A. S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130ºF. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric pressure and by heat transferred to it from rock at high temperature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. METHODS Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1941