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By David A. Hall

We present an analysis of the propagation in a uniform tunnel of semi -circular cross section that contains two axial conductors. In particular, we show that, even if one of these conductors has high ohmic loss, one of the two propagating modes has relatively low attenuation. This corresponds to the situation where an unloaded dedicated wire is used to improve radio frequency communication in a mine tunnel that contains a heavily loaded trolley wire.

Jan 1, 1978

By K. L. Paciorek

The primary objective of this program was to determine the toxic fume and fire hazard of elastomeric noise abatement materials with a limited effort expended on the evaluation of specific treatments applied to mine timbers. Under the conditions employed, for a dimethyl silicone rubber, formaldehyde presented the major toxic threat; acrolein was the main toxic species for both polyester and polyether urethanes and an acrylonitrile-butadiene-styrene resin; in the case of flame-retardant styrene-butadiene rubber compositions, hydrogen chloride, and in the case of PFA-treated timber, furfural, were the major toxic compounds. Of the materials studied, the flame-retardant styrene-butadiene rubbers presented the greatest toxic hazard. The generated data have been reduced to toxic load tabulations amenable to employment for potential hazard assessment.

Jan 1, 1982

By Kenneth H. Johnston

The Weber pool in Washington County, Okla. (fig. 1), covers an area extending from 2 miles east and slightly north of Bartlesville, Okla., to a point approximately 2-1P tiles northeast of Dewey, Okla. The pool is a part of the area designated by the Standing Committee on Oil Field Nomenclature, Kansas-Oklahoma Division, Mid-Continent Oil & Gas Association, as the Bartlesville-Dewey field. In the following discussion of the geology, development, and exploitation of the Weber pool, the writers, by means of structure maps, cross sections through various parts of the reservoir, and tabulated development data and production statistics, have recorded salient information on a field that was developed before .1910 in an Area that has been repressured since 1926. The total oil production to January 1, 19.0., from the 2,639 developed acres considered in this report, was approximately 14 million barrels, or a recovery of about 5,3;2 barrels per acre, or 227 barrels per acre-foot. The production of the estimated 18 million barrels of recoverable oil remaining in the Bartlesville sand reservoir will require the initiation of additional secondary-recovery practices on some of the leases and the application of a more systematic repressuring program on others.

Jan 1, 1950

By Richard H. Spencer

The purpose of this program was threefold: (1) to identify the symptoms of poor or inadequate performance of trolley carrier phone systems; (2) to assess the root causes of performance difficulties and classify them on the basis of equipment, coupling, or transmission; (3) to propose, analyze, test, evaluate and verify means of overcoming performance difficulties. Based on interviews and discussions with knowledgeable persons, laboratory experiments, and in-mine measurements, it was determined that the major impediment to good carrier phone system performance is the extreme signal attenuation found on the trolley wire/rail largely due to the many bridging loads. Three means are identified to help overcome the performance difficulties: the low impedance trolley wire, a method of improving performance by capacitively loading the transmission line; the dedicated wire, a low-loss means of extending trolley signal coverage; the use of isolators to remove the offending bridging loads at the carrier frequency. Other subjects treated in the report are design reviews of hardware, guidelines for the use of information in the report, recommendations, and a description of a probe for measuring trolley wire current.

Jan 1, 1977

By Marcel Vallée

Frequently, costs overruns and defaults in mining project performance result in serious problems and headaches for all project participants and impact on corporate objectives, profits and image and, occasionally, lead to project failure. As mining professional s, we should be very concerned that, in a recent World Bank paper (Weber-Fahr, 2001), geological and technical risks were considered the most important ones facing mining projects. Whenever we manage to reduce or minimize these risks, we are in better position to overcome the environment-, market-, finance- and community-related ones. The causes of this situation seem rather systemic, as a fairly long list of industry problems with new pro jects has been described in industry papers in pas t and recent years. A brief review of industry problems with mining projects will be given first, followed by a review of the basics of the current Quality Management and Continuous Improvement perspectives that have evolved from earlier quality control and quality assurance systems and policies. Particular particular attention will be given to the work of W. E. Deming. As the system approach is an essential part of such policies, it will be described succinctly. Given that poor communications and interactions among geologists, mineral processors and mining engineers/operators ca n seriously affect project efficiency and profitability, these interrelated processes with in the mining systems will be analyzed and modelled and the impacts of such situations will be described through a number of anonymous case histories and examples. A synthesis of Dr Deming's management system, includ ing his Four teen P oints and System of Profound Knowledge, will be prese nted .

May 1, 2002

By José Dávila

El presente trabajo señala el programa de manejo de datos del monitoreo biológico aplicado en BHP Tintaya. El estudio informa sobre el estado actual de las variables del medio natural, tales como la flora y la fauna, así como sus características temporales y espaciales para así diseñar las soluciones a los riesgos e incidentes ambientales referidos a ecosistemas naturales. Asi también, la investigación se complementa con el monitoreo de suelos, aguas, aire y residuos de diverso tipo, al reconocer que las actividades mineras se efectúan inmersas en medios naturales. Por lo que las empresas mineras , están obligadas a proteger el equilibrio y adecuado funcionamiento de los ecosistemas naturales.

Sep 13, 2001

By F. Fraas

ELECTROSTATIC methods are used to separate and concentrate or purify granular particles derived from ores or various synthetic and agricultural products. Compared with other separation methods that require many technological refinements, the electrostatic attraction of fibers, grass, and seeds to charged surfaces clan be accomplished under the most primitive circumstances, and the early development of this method of beneficiation seemed very promising. Precise application of the method to provide high selectivity, however, is a complex procedure, and interest in this method declined. During this period Mr. O. C. Ralston initiated a Bureau of Mines research program oil electrostatic separation. It is the purpose of thins publication to describe the development of the electrostatic method of particle separation from the early beginning to the present resurgence of interest. Most of the information for this description bas been derived from references, a few of which were not available for thorough review. Much information has been drawn from the investitions of the Bureau. Acknowledgments Mr. O. C. Ralston, former Chief metallurgist of the Bureau of Mines, began the research program on the subject and did research on the mils literature. Both Mr. Ralston and Mr. H. B. Johnson, former president of the Huff Electrostatic Separator Co., furnished patent references. A critical review by Mr. F. D. Lamb, Research director, and Mr. M. J. Spendlove, Supervisory metallurgist, Bureau of Mines, College Park Metallurgy Research Center, lifts been of much value in preparing this report.

Jan 1, 1962

By Roger K. McLimans, Venkatramaiah N. Vasudev, Christian Knudsen, Stefan Bernstein, Dirk Frei

Computer Controlled Scanning Electron Microscopy (CCSEM) analyses of sediment samples from coastal regions of Kerala and Tamil Nadu states and the heavy mineral deposits of Chavara, South India, show large lateral differences in the titanium content in ilmenite due to varying degrees of iron leaching. As the depositional environments for the sands with varying degrees of ilmenite alteration are comparable, the cause for the different degree of alteration is due to differences in the primary source of the ilmenite or to differences in the geochemical history of the ilmenite grains during transport from source to deposit. The CCSEM analyses of the heavy mineral fractions show that source of sediments with a high content of titanium-enriched ilmenites, mainly the heavy mineral deposit around Chavara, resides in the khondalite belt of South India (granulite facies metasediments). The less titanium-enriched ilmenites are sourced from other rocks in the area such as the charnokites. Those conclusions are based on the high MgO content in the leached ilmenites, chemical composition of the accompanying garnets (low CaO and high MgO), and the concentration of aluminum-rich minerals in the sands.

Jan 1, 2005

By Krishna P. Sinha

An investigation was made to determine the creep behavior of oil shale at elevated temperatures. During the first phase of the investigation, work done on creep behavior of geologic materials was reviewed and triaxial creep tests on oil shale were planned. Tests at temperatures up to 250°C and axial stress up to 3000 psi were conducted at no confinement and at confining pressures equal to 1/3 and 2/3 of axial stress. Wide variations in the elastic properties as well as creep characteristics are exhibited. Creep deformation is more pronounced at elevated temperature but no definite quantitative remarks can be made regarding effect of grade of oil shale due to wide scatter and limited number of data paints. Primary creep can be described by a power law. Secondary creep seems to be an experimental function of deviatoric stress. Teritary creep was not observed within the test duration (24 hours in most tests).

Jan 1, 1983

Jan 1, 1957

By V. Labiouse, R. Gärber

The paper aims at clarifying the up-to-now misappreciated role taken by pore water on the design of deep tunnels in saturated porous media. Numerical simulations with a non-dimensional FEM-model emphasise the influence of pore water characteristics (in situ pressure and compressibility) and boundary conditions (lining permeability) on the short and long term underground-structure equilibrium states. These results cannot be achieved by means of monophasic total stress analyses. Dieser Beitrag untersucht den Einfluss des Porenwassers auf die Dimensionierung von tiefen Tunnelbauwerken in wassergesättigtem Untergrund. Numerische Simulationen mittels eines dimensionslosen FEM-Modells betonen den Einfluss der Porenwassereigenschaften (in-situ Druck und Kompressibilität) und der hydraulischen Randbedingungen (Tunnelausbaudurchlässigkeit) auf Kurz- und Langzeitverhalten des Untergrund-Ausbau Gleichgewichts. Diese Ergebnisse können nicht ermittelt werden anhand von Einphasen- und Totalspannungsmodellen. L’article s’intéresse au rôle méconnu de l’eau interstitielle dans le dimensionnement de tunnels profonds creusés dans des milieux poreux saturés. Des calculs adimensionnels par éléments finis soulignent l’influence des caractéristiques de l’eau interstitielle (pression in situ et compressibilité) ainsi que des conditions aux frontières (perméabilité du revêtement) sur les équilibres court et long terme de l’ouvrage. Ces résultats ne peuvent pas être obtenus par des calculs en contraintes totales.

Jan 1, 2003

By W. Zhu

ABSTRACT: This paper presents further developments of the principle of Construction Process Mechanics of rockmasses, The principle of loading variations analyses in space-time is systematically described. To demonstrate the applicability of the theory and method, the effect of the construction process of two practical engineering cases are analysed. ZUSAMMENFASSUNG: Das Mechaniksprinzip vom Konstruktionsprozess des Massenfels wird in diesem Aufsatz weiter Entwickelt.. Das Prinzip von Variationsladungsanalyse mit dem Zeit-Raumseffekt wird systematisch erklaert. Um die Anwendungsmoeglichkeit der Theorie und der Methode zu anschaulich darstellen, das Mechanikseffekt des Konstruktionsprozess wird fuer zwei praktische Anwendungsbeispielen zergliedert. : RESUME: Dans ce papier le development se fait pour principles de la mechanique de process de construction . Le principle de variable analyse considerant effet de temps et de Space est present ´e . Pour demonstrer l´appilicabilite de le theorie et la methode , l´èffect de processe de construction pour ce deax examples sont analysés .

Jan 1, 2003

By Y. Y. Jiao, J. G. Cai

To investigate the dimensional effect on shock wave propagation in jointed rock masses, a 2-D and a 3-D calculation of a site test are performed respectively by using Discrete Element Method, the simulated results are compared with test data. It shows that, in modelling shock wave propagation and attenuation in jointed rock masses, when the explosive along explosion chamber is long enough and the joints are dense enough or uniformly distributed, the model can be considered as plane-strain problem, 2-D results are good enough to fit with test data. 2-D modelling, with much more details of rock masses taken into account, can be applied to make critical engineering judgements instead of 3-D modelling in some cases.

Jan 1, 2003

By C. A. F. Sweet

The inter-relationship between these parties and the effect on the outcome of the project is often grossly underestimated. There are numerous success stories where the parties have worked as complementary teams aiming at the best outcome for the client company and achieving significant success. While there are a good number of occurrences where either the roles of the parties were unclear or perceived to be different from what others in the team believed or required them to be and the results were less than desired. This usually resulted in ongoing conflict, incorrect focus, working to different agendas and the result being a less than optimum result to Client Company. Mining, by its very nature of exploring where you cannot see, be it a shaft being sunk, tunnel being developed or other excavation that needs to be made, requires a very special working relationship between the parties. To understand this, and it applies equally well to mine and plant construction and other multiple function projects, one needs to start by describing the relationship of the parties. Often people believe that because they manage ongoing complex operations and large numbers of people that they can manage projects and as such the participants will ?fall into line.? At the outset it needs to be stressed that ?Project Management? is a specific type of management and needs to be understood as such. There are enough Colleges and Universities that teach project management, not only as a subject but also as a Master Degree. As you start up your project the relationship you establish between the client, project team (C.P.T) and the Engineering, Procurement, Construction and Management team (EPCM) will largely determine how successful your project will be. It is essential that from the outset a spirit of co-operation, support and respect be nurtured, and that it be actively carried through the project life cycle. There are several methods to facilitate this including team building exercises right at the start. This time and money will be well spent and recouped many times over during the project life cycle.

Jan 1, 2005

By Alex C. Smith, Michael J. Sapko

A series of explosive detonation experiments was conducted in NIOSH’s Bruceton and Lake Lynn Experimental Mines to evaluate low level (<6 psig) detonation wave propagation behavior in single and multiple entry configurations. Entry cross-sectional area varied from 5 to140 m2 and explosive weights of Pentolite ranged from 0.24 to 2.4 kg. Behavior of the detonation wave was evaluated through recording of the pressure as a function of time and distance from the explosive detonation in single and multiple entry interconnecting tunnels. Peak pressure from detonation of an explosive in an underground mine maintains magnitude for a greater distance than is the case on the surface and is shown to follow the simple scaling rela-tionship P = 702.8(W/Vt)0.514(0.65)n, where P is the peak detonation pressure in kPa, W is the weight of the explosive charge in kg, Vt is the total volume in m3, and n is the number of splits, n = 0, 1, 2, …n. The total energy, or impulse, I, generated by these detonations can be expressed as I = 1.34(W/A)0.64n, where W is the weight of the explosive charge in kg, A is the area of the main tunnel in m2, and n is the number of side en-tries, n = 0, 1, 2, …n.

By L. J. Kane

Applications are described of various methods for determining the weight concentration and physical properties of solid and liquid impurities of gases in connection with problems encountered in synthesis-gas production. Of special interest among these methods may be listed: 1. A method developed for determining, the weight concentration of solid and liquid impurities in. hot, crude synthesis gas containing a high concentration of moisture. 2. A method developed for the same purpose but for highly purified synthesis gas or atmospheric air. 3. A method for obtaining a uniform dispersion of dry duet or, a microscope slide for particle-size determination or other purposes.

Jan 1, 1954

By C. J. Burkhalter, H. Andrade, T. C. A. Gardner, J. P. Campbell

During the 1990’s several copper heap leach facilities treating crushed and agglomerated oxide and sulfide ore were constructed in South America. The majority of these facilities have been in operation for at least three years, during which time the operators have been able to monitor the performance of the heaps. The basis for the paper is a compilation of these operators’ experiences, leading to a discussion of the lessons learned over the past decade. Several key geotechnical issues are examined, focusing upon the integrity of the ore, drainage material and pipe network, along with the success of any inter-lift liners.

Jan 1, 2002

By Mark Abernathy

When most people think of a motor vehicle accident, the direct costs resulting from that accident, such as vehicle repair or towing charges, are generally easy to quantify. However, the indirect costs associated with an accident are often overlooked. These indirect costs can take a tremendous toll on a company in more ways than you might think.

Jan 1, 2006

By Ralph W. Barbaro

In the mineral industry, the objective of a mining venture is to extract, process, and market a mineral commodity in such a manner that the profit of the venture is maximized. In a mining venture, a company normally has control over mine production scheduling, the selection and location of processing facilities (mineral beneficiation plants, smelting plants, refineries, or blending facilities), processed ore blending, and the selection of markets. The flexibility of the above factors provides many alternatives to satisfy the needs of each market with regard to quantity and quality of ore. The purpose of this paper is to present a mathematical model for determining the alternative that yields the maximum profit. Production planning is generally concerned with the best utilization of fixed resources, more specifically, with the determination of production and inventory levels to meet fluctuating demand requirements. A mine can be any source of ore such as an entire mine, a production unit within a mine, or an independent supplier. The objective of production scheduling is to determine the times at which each mine will be used and to allocate a required level of production. Production planning and scheduling problems are intimately associated with the location of new and existing mines and processing facilities. Although the location of the mines is usually fixed, there can be considerable flexibility in locating new processing facilities, in the selection of the processing plant, and in blending the ore before and after processing.

Jan 1, 1983

By S. J. Hemberger, F. W. Lee, J. H. Swatz

"INTRODUCTION This investigation was undertaken in 1939 for the purpose of securing the necessary information relating to the field techniques and accuracy that would be needed for magnetically surveying State-wide areas. The Florida,peninsula was chosen for such a study for two reasons: First, because it is geologically ideal for such an investigation, since it comprises a series of unconsolidated, flat-lying Tertiary and Cretaceous sediments of low magnetic susceptibility covering a complex and much-folded crystalline basement comprised of rocks carrying strongly -paramagnetic materials; second, because information concerning the structural trends of the crystalline basement would be of great interest and Importance in the study of Appalachian orogeny and the relationship of the Florida Peninsula to both the Appalachian and Antilleantectonte systems. The results of this magnetic survey have clearly demonstrated that the magnetic anomalies reflect variations in the crystalline a basement. To the degree which the structures of the crystalline basement control the structures of the overlying sediments these results are useful for oil exploration.MAGNETIC OBSERVATIONSAll magnetic measurements were made with a vertical Aekania magnetic variometer having a temperature compensated needle. All observations were tied into two base stations located at Fort. Myers and Gaineeville, Fla. The absolute vertical magnetic intensities at these two bass stations were determined by the United States Coast and Geodetic Survey within an accuracy of + 10 gammas. The accuracy of the base station variometer used in the present survey was of the order of ± 3 gammas. The sensitivity throughout the survey of the magnetic variemoter used on the traverses approximated 30 gammas per scale division and it is estimated that the probable error between stations along a traverse would be about + 5 gammas. Measurements were started on traverse C near Fort Myers and tied into the Fort Myers base station established by the Coast and Geodetic Survey. Twelve traverses, comprising 1,500 station observations, wore occupied between the Fort Myers and Gainsville base stations. When the cumulative total of these 1,500 interim observations was tied into the Gainesville base station it was found to differ by only 30 gammas from the value obtained by the Coast and Geodetic Survey for that base. The observations were adjusted for this difference."

May 1, 1945