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By Eric K. Albert

Computer oriented simulation techniques can be effective in the design and analysis of complex mining systems. In fact, a number of computer software products are available for mine systems simulation. However, previous models have tended toward being either data-intensive and deterministic, or data-limited and highly stochastic. The need for a fully integrated package with a simplified user interface has never been more apparent. In this paper, the design of a surface mining simulation model documented in Albert (1986) is described. The basic features of the surface mining system and their counterparts in the simulation model are discussed. The methods and algorithms used to implement these subsystems are presented. Considerations of information management and software design are illustrated, especially as they apply to the application of the package by a mining engineer. An example is provided to demonstrate the concepts embodied in the model and to show how a surface mine is simulated from mine parameters.

Jan 1, 1989

By J. A. Madonna

Independent prospectors and small to large-scale exploration company personnel have requested, and are in need of, guidance in geochemical field sample collection methods which will provide the most reliable results during chemical analysis. In cooperation with analytical laboratories, experienced geochemical exploration scientists and mining companies a systematic collection procedure has been developed. The procedure consists of collecting uncontaminated, water, sediment and rock chip samples of the appropriate quantity and/or dimensions to meet the needs of analysis.

Jan 1, 1999

By Bradley C. Bockrath

Some thirty coals were evaluated for liquefaction activity under a mixture of CO and H2 at 425° C. The viscosity of the liquid products was taken as an indicator of the degree of liquefaction. It was found that the direct liquefaction of a particular coal may be beneficially influenced by the presence of pyrite. Active pyrites are often found in the native mineral matter of the coal itself. For example, subbituminous and bituminous coals and lignites of relatively high pyrite content were found to liquefy more readily than similar coals or lignites which were poor in pyrite. The reactivity of inactive coals could be improved by using blends with active, pyrite-rich coals. In addition, pyrite was effective when added separately as pyrite concentrates obtained from coal beneficiation operations. Various other iron- and sulfur-bearing additives were also effective when used in combination as added slurry-phase catalysts, including iron oxides and mineral residues derived from liquefaction of active coals. Under liquefaction conditions, pyrrhotite ( Fe I- x5) is formed from pyrite or from the iron oxides and many sulfur containing species. Pyrrhotite was shown to be a hydrogenation/dehydrogenation catalyst for tetralin but is not active for initiating a variety of free radical reactions that do occur when pyrite is heated with tetralin. The role of pyrite in coal liquefaction is complex and still not well understood.

Jan 1, 1981

By Garry W. Stevenson

Data from many case histories reporting tunnel boring machine penetration rates in rock with unconfined compressive strengths greater than 70 MPa (10,000psi) are summarized. The case history data are useful for comparing estimated penetration rates with historic performance in similar rock types, particularly in granitic and metamorphic rocks. TBM exhibit higher penetration rates in sedimentary rocks than in granitic and metamorphic rocks. Data for the two groups of rocks are summarized separately.

Jan 1, 1999

By Liane L. M. Kadnuck

This report summarizes the results of a hydrologic research study conducted by the U.S. Bureau of Mines (USBM) in cooperation with Energy West Mining Co. at the Deer Creek and Cottonwood Mines, near Orangeville, UT. The USBM evaluated hydrologic and overburden failure data to assess the response of local ground water to underground coal mining in single-and multiple-seam conditions. Fourteen springs located over the two mines were investigated in the study along with overburden failure response caused by longwall panel extraction. Spring discharge was compared to climatic variation and time of undermining to quantify response to undermining. Spring discharge had been reduced owing to below-normal precipitation during the period evaluated. The response of springs to mining in the vicinity was influenced in part by the thick overburden present at the study site the presence of hydrophilic clays and mudstones in the overburden stratigraphy, and elevation of the springs above mine level, which buffered the effects of undermining.

Jan 1, 1994

By Boswell GB, Mori W, Stevens MR

The Onemana prospect is located on the eastern Coromandel Peninsula, North Island, New Zealand. Systematic exploration involving surface geological mapping, geophysics, rock and soil geochemistry, reverse-circulation and diamond drilling has identified a number of important features of a fossil hydrothermal system at Onemana. This relatively intact gold mineralised system is hosted within a sequence of rhyolitic volcanics and volcaniclastics, overlain by lake sediments, sinters and hydrothermal eruption breccia. The system lies within a graben/half graben bounded by major NE-trending faults which form the approximate boundaries to hydrothermal alteration.

Jan 1, 1995

By H. B. Comstock

This paper reviews the trends in supply and consumption of the principal magnesium compounds in the United States in relation to domestic requirements and world resources. The data are confined to these principal magnesium compounds: Magnesium chloride, magnesium hydroxide, precipitated magnesium carbonate, and magnesium oxide (commonly referred to as magnesia). The properties and uses of magnesium compounds are shown in various chapters of' the 2nd edition of Industrial Minerals end Rocks. 3/ The third edition of this reference is in preparation. A more recent description of properties, uses and sources of magnesium compounds appears in a Bureau of Mines publication.4/ The American Iron and Steel Institute and the Refractories Institute have published comprehensive data on the properties and uses of basic refractories. Many magnesium compounds are prepared by the producers to meet specifications set by individual consumers.

Jan 1, 1960

By Pedro Gamio Aita

Dado que la Organización de las Naciones Unidas señaló que el Perú es un país con alto grado de susceptabilidad ante los efectos del cambio climático, se estableció una política de mitigación y adaptación que asegure la preparación de las regiones. Entre los objetivos que comprender dicho planeamiento tenemos: lograr que los biocombustibles de primera y segunda generación representen alternativas competitivas a los combustibles fósiles , al tiempo que asegura la sostenibilidad de su producción; aumentar la capacidad de generación de electricidad con centrales eólicas, centrándose en el desarrollo de la energía eólica de la costa. Asimismo, valorar el reto de incorporar la integración de fuentes de energía renovables descentralizadas.

Sep 12, 2011

By A. G. Guy, T. B. Lindemer

A second intepation of the Fick law has been developed and applied to three-place data generated from the Gosting and Fujita solution of the diffusion equation. This integration provides new mathematical techniques for the analysis of experimental data. Through use of the synthetic data it is shown that for concentration-independent interdifiusion coefficients these techniques permit a more accurate determination of the coefficients than does the usual Boltzmann-Alatano analysis. Another technique, applicable to the most general concentration-dependent diffusion coefficients , can be used to determine whether given sets of coefficients are consistent with the experimental ternary concentration-distance curves. DURING the past 10 years the subject of three-component diffusion has advanced from the stage of a laboratory curiosity to the status of an accepted portion of physical metallurgy.1 In the course of this development the underlying treatment for two-component sys- tems was extended and generalized to accommodate the added component, but fundamentally the analyses currently employed for ternary systems are analogous to those previously developed for binary systems. There are several indications that an improved analysis is needed for the ternary case. First, the two cross coefficients, D312 and D321 are typically an order of magnitude smaller than the direct coefficients and consequently are difficult to determine with adequate precision. Second, instead of a single concentration-penetration curve (as in binary diffusion), there are four such curves in the usual determination of ternary diffusion coefficients. These curves have definite theoretical interrelationships, but actual experimental curves exhibit significant departures from these relationships. Finally, the amount of data needed to adequately describe the diffusion behavior of a ternary system is so large that radically new methods are needed to facilitate the gathering of these data. ICirkaldy2j4 has proposed several possible analyses of ternary diffusion data, including some of the methods in current use. A "second-integration" procedure proposed by him4 differed in important respects from that presented here and was not carried to the point of application. Two other methods have been explored by the authors and will be published separately; these are a numerical analysis technique and a method for the analysis of a single ternary diffusion couple. Still other analyses are being explored by various investigators. At present it seems likely that the final analysis of ternary diffusion that evolves will be a composite

Jan 1, 1968

WE the undersigned, being ell persons of full age and citizens of the United States, and a majority resident of the State of New York, desiring to form a corporation pursuant to the provisions of the membership Corporations Law for the purpose of incorporating, as provided in section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and 6he reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its. Council; that the undersigned are all members of said Council as the same was constituted on the 296h day of December, 1904. III. That on said last-mentioned date a regularly called meeting of said association was held at its office in the Borough of Manhattan, City of New York; that thirty days before such meeting notice of the intention to incorporate said association was given by mail to each member thereof whose residence or post-office address is known; that at said meeting the following resolutions were offered, seconded and duly adopted by the unanimous vote of all its members then present, to wit: "Resolved, That it is the sense of the members and associates of the American Institute of Mining Engineers in general meeting assembled that it is desirable and necessary for the well being of said association and its members and for the furtherance of the objects for which the same has been formed, that said association incorporate under the Membership Corporations Law of the State of New York; "And Further Resolved, That the Members of the Council of this Association, or a majority thereof, be and they hereby are authorized, in accordance with the provisions of Section 5 of Article I. of the Membership Corporations Law, to incorporate this association for the same purposes for which it has been organized and conducted, in the manner provided in Article 11. of said law; "And Further Resolved, That the name of said corporation as hereby adopted by this meeting shall be American Institute of Mining Engineers; "And Further Resolved, That the said incorporators shall be named in the Certificate of Incorporation as directors of such corporation until its first annual meeting, and that such directors and their successors in office shall be and they hereby are authorized to enact and adopt a Constitution and By-Laws for the government of said corporation." IV. That the name of the proposed corporation is American Institute of Mining Engineers. V. That the purposes for which this corporation is to be formed are: To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings

Jan 1, 1928

By Darrell L. Beddard

The Loma Prieta earthquake occurred on October 17, 1989 at 5:04 PM, Pacific Daylight Time. It measured 7.1 in magnitude and was felt from Los Angeles north to the Oregon state line and east to western Nevada. The epicenter of the earthquake was located along the San Andreas Fault, in the Southern Santa Cruz Mountains just north of the City of Watsonville, California. It was the largest earthquake to occur in the San Francisco Bay area since the 1906 earthquake. A total of 87 aftershocks of Magnitude 3.0 or larger were recorded within 21 days after the seismic event. As a result of this earthquake thirteen State-owned and five locally-owned bridges were closed to traffic. Three of the most publicized State-owned structures closed to traffic were Struve Slough Bridge, San Francisco-Oakland Bay Bridge and Cypress Street Viaduct. Struve Slough Bridge was twin slab bridges that collapsed and were rebuilt and open to traffic three months after the earthquake. San Francisco-Oakland Bay Bridge experienced collapse of upper and lower spans at Pier 9 and was reopened to traffic one month after the earthquake. The Cypress Street Viaduct experienced collapse of 48 bents that resulted in the upper roadway falling onto the lower roadway.

Jan 1, 1995

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) The governing body of the Imperial College of Technology, London, S. W. (Royal School of Mines), will shortly proceed to the appointment of a Professor of Metallurgy. This important Chair has been filled in the past by such eminent metallurgists as John Percy, Sir William C. Roberts-Austen, and others. Inquiry has been received at the office of the Institute for an engineer to examine a mica, deposit in one of the New England States. The position of converter blower at. a side-blow Bessemer steel casting plant is vacant.

Jan 4, 1913

By Kevin Jinrong Ma

Underground mines often experience roof falls in entries, crosscuts, and intersections of active mining sections, main travel ways, and belt entries. Roof fall heights greater than 20 ft (6 m) make re-bolting of the newly exposed roof dangerous and impractical. To protect mine personnel, belts, moving vehicles, and other facilities, mine operators typically install steel structures such as square or arch sets in the roof fall areas. Wood lagging is usually installed between the steel-sets to enclose the area and protect the entry from recurring falls. Usually the void space above the steel-sets and laggings is backfilled. However, backfilling high roof fall voids is costly, which causes some operators to leave the voids open. In this case, durability of wood over time and the capability of the steel-set and wood lagging to resist falling rocks are unknown. During the last few years, Keystone Mining Services, LLC (Jennmar Corporation affiliate engineering company) designed, tested, and developed an impact-resistant lagging system to protect steel-sets1. Various steel-sets protected with the impact-resistant lagging were approved by MSHA and installed in different underground roof fall rehabilitation projects. This paper presents (1) design, development, and laboratory testing of the patent-pending impact-resistant lagging panel, (2) steel-set design methodology according to the American Institute of Steel Construction (AISC) national standard, and (3) impact-resistant steel-set design method based on Law of Conservation of Energy. Two underground cases are reviewed to demonstrate the successful application of the impact-resistant lagging system.

Jan 1, 2011

By G. C. Wallick, W. R. Foster, J. G. Savins

The theory of the differentiation method for the Couette flow experiment is reviewed. Particular attention is given to the requirements on data analyses in the case of the class of non-Newtonian materials described as viscoplastics, i.e., materials characterized by a yield point or yield stress. Here changes in boundary conditions arise when the shearing stress attains a critical value with the result that the form of the basic integral equation for Couette flow is determined by the flow conditions existing during the measurement. INTRODUCTION In the preceding papers in this series,l,2 the salient features of the differentiation method of rheological analysis in Poiseuille-type flow were discussed. It was shown that a dual differentiation-integration method analysis of the Poiseuille flow of idealized generalized Newtonian and visco-plastic models could be used to develop a spectrum of highly sensitive response patterns in terms of certain characteristic derivative functions. These functions were shown to optimize the selection of the most appropriate functional relationship between f(p) and p from the Poiseuille flow experiment. The present paper reviews the theory of the differentiation method as applied to the equally important Couette flow experiment. We will also discuss the range of variables over which the basic integral equation for Couette flow is applicable when the non-Newtonian material is of the viscoplastic type, i.e., characterized by a yield point or yield stress. THEORY Having described the application of the differentiation method to Poiseuille-type flow in the preceding papers, we now proceed to the case where the test liquid is confined to the annular space between coaxial cylinders of length L, one of which is in motion, i.e., Couette flow, formulating the basic integral equation after the method of Mooney.3 The observed kinematical and dynamical quantities are the angular velocity O and the torque T. Here, the one nonvanishing component of the shear-rate tensor is

By F. R. Ploeger, J. H. Crocket

"IntroductionRocks in the Kirkland Lake district form part of the Timiskaming Group, a south-facing homoclinal sequence of wackes, conglomerate, trachytic flows and pyroclastic rocks and syenitic intrusive rocks. Hewitt (1963) indicates that the thickest section, about 5 km, of the Timiskaming Group rocks is attained in Lebel Township. Several writers (Thomson, 1948; Hewitt, 1963; Hyde, 1978; Jensen, 1978; and Downes, 1979) have observed that the Timiskaming Group unconformably overlies the Keewatin volcanics, particularly along the northern contact. Recent work by Downes (1979) in McGarry and McVittie townships to the east of Kirkland Lake has shown that much of what had formerly been classified as Timiskaming actually belongs to an older group of rocks, the Larder Lake Group (Jensen 1978).General GeologyA series of fluviatile, braided-stream sedimentary rocks (Hyde, 1978) form the oldest of the three major rock suites at Kirkland Lake. Conglomerates constitute a large proportion of these sedimentary rocks and typically contain a large percentage of a variety of locally derived alkalic rock clasts as well as the distinctive red jasper iron-formation pebbles (Fig. 1a). The associated wacke units can be massive to finely bedded and are interbedded with the conglomerate. They also contain a large alkalic tuffaceous component.Interbedded with these sedimentary rocks are alkalic extrusive rocks, including tuffs, agglomerates, breccias and flows, which represent episodes of fissure and explosive crater eruption (Cooke and Moorhouse, 1969). The tuffs, although dominantly alkalic in composition, are commonly reworked and contain sedimentary features such as graded bedding, scouring and crossbedding (Fig. 1 b). The trachytic flows are massive to porphyritic and outcrop mainly east of Kirkland Lake in the adjoining townships. Altered leucitic porphyritic flows, locally referred to as red and green spotted trachytes, commonly occur."

Jan 1, 1982

By J. Muralha, L. Lamas

"Given the results of triaixial tests, regressions are commonly used to evaluate the parameters of failure criteria that model intact rock strength and to perform statistical inferences used to evaluate characteristic values defined in EC7. Statistical robustness of these inferences is affected if the basic hypothesis underlying regression are not met, namely homoscedasticity (constant variance of the errors). This paper presents analyses of 23 sets of triaxial tests, starting by the evaluation of the regression parameters of the Mohr-Coulomb linear criterion and of the Hoek-Brown non-linear criterion, followed by carrying several statistical tests to check the homoscedasticity null hypothesis of independence between the variance of intact rock strength and the confining stress.INTRODUCTIONThough rock engineering design is clearly included in the scope of Eurocode 7(EN1997-1), its implementation raised a wide discussion regarding the applicability of structural safety concepts to geotechnical design of construction works in or on rock masses. The basis of the limit state design philosophy adopted in EC7 is that, for each particular design situation, all the possible limit states for a structure, or part of it, shall be considered and that it shall be demonstrated that the likelihood of any limit state being exceeded is sufficiently small. Though EC7 allows the limit states to be verified by one or a combination of methods, use of calculations is by far the most used, and it is often confused with the EC7 itself. It involves using characteristic values of actions, ground properties and geometrical data, as well as obtaining their design values by the partial factor method.Characteristic value of a given material property is defined in Eurocode (EN 1990) as: “value of a material or product property having a prescribed probability of not being attained in a hypothetical unlimited test series. This value generally corresponds to a specified fractile of the assumed statistical distribution of the particular property of the material or product”. As regards the design value of a material or product property, according to the Eurocode it is a “value obtained by dividing the characteristic value by a partial factor”."

Jan 1, 2015

Japanese pig iron production in 1973 registered about 90 million tons. As clearly seen from the productivity (2.04 t/m3/D), and fuel ratio (494 kg/t-pig), the Japanese steel industry has maintained quite high levels of efficiency in blast-furnace (BF) operations. Among the many factors which have contributed toward these high levels of efficiency, the use of high quality coke is very important. The Japanese steel industry imports about 85% of its metallurgical coals from various countries of the world, including Australia. The effective use of these metallurgical coals of various origins in accordance with their re- spective properties is most essential for maintaining coke quality. This paper describes coking properties of various metallurgical coals and blending techniques based on these coking properties, in relation to the specifications of coke quality required for efficient BF operations. This paper also describes briefly new technology for expanding the scope of the use of coking coals.

Jan 1, 1975

By M K. de Brodtkorb

Late Cenozoic ore deposits æPrecious and base metal-richÆ and æSn-Ag-polymetallicÆ ofNorthern Puna are associated either with Middle Miocene dacitic volcanic-dome complexes or with Upper Miocene dacitic-andesitic volcanic centres.   Ore mineralogies and their related volcanism are discussed. A strong link is observed between the Cenozoic Metallogenetic Province of Northern Puna and the Southern Bolivia Tin and polymetallic provinces.  

Jan 1, 1995

By Stephen Birch

Latouche, or the Beatson plant of the Kennecott Copper Corpn., is located in the Prince William Sound district of Alaska about 80 miles west of Cordova and 60 miles from Seward. Ore was discovered and claims located on Latouche Island in July, 1897. The mines were worked in a desultory manner until 1910, when the property was acquired by the Kennecott Copper interests. The first shipment of ore was made in 1904; only the higher grade ore was mined and no attempt was made to treat the ore until it was taken over by the Kennecott company. Since that time the mine has been developed to produce 1500 tons a day and a mill has been erected for treating this tonnage, using flotation entirely. The orebody is more or less lenticular in shape with a maximum width of about 280 ft. and a length of about 800 ft. The southern end of the lens is split by a horse of waste for about 400 ft. The hanging-wall limit is a well-defined fault associated with a band of pyrrhotite, having an average dip of 60". There is no defined foot wall, the value of the ore governing the limits of the mining; in one part of the mine, however, it is defined by a minorfault. The orebody is in a shear zone of the country rock of graywacke and slate. The principal mineral is chalcopyrite associated with pyrite and quartz. The mine is situated a few hundred feet from tidewater; the mill is on the beach and the ore is hoisted direct from the mine through a vertical shaft into the mill bins. Until the past year practically all the mining had been conducted in open pits. During the past two years, the ore above the 200-ft. level has been developed and a system of stoping devised to recover this ore; however, this system has not been in use long enough to give any definite results as to costs or efficiency. It consists, principally, of dividing the orebody into stopes, across the full width of the orebody, 70 ft. wide with a pillar 30 ft. wide between the stopes. Raises are driven through the stopes at intervals of about 60 ft. and all the ore is broken by drilling from these raises; in other words, similar to a shrinkage stope, doing the drilling from the raises instead of setting up on the broken ore as is customary. The ground is very much broken up by clay slips and seams running in every direction. Shrinkage stoping had been

Jan 1, 1925

By Ernest M. Spokes

Maximum fan efficiency can only be obtained when the fan has the correct combination of size, speed, and blade setting to provide the required flow of air against the mine resistance. As the mine grows older, resistance decreases unless old workings flow is restricted, and new combinations of speed and blade setting or different fan sizes may provide greater economy.

Jan 1, 1977