Search Documents

By B. J. Moore

This publication contains analyses and related source data for 269 natural gas samples from wells and pipelines in 18 States. All of the samples were obtained and analyzed during, calendar year 1979 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the general public. Twenty-one previous publications have presented tine results of 11,883 gas analyses made prior to 1979. The first three, Bulletins 486,4 576,5 and 617,6 contain analyses and related source

Jan 1, 1980

By Wilbur I. Duvall

This report presents experimental data on crater formation in four rock types. From an analysis of these data a general theory of rock breakage by explosives is deduced. This theory accounts for most of the rock breakage and other phenomena that occur when a concentrated charge is detonated in a drill hole near a free surface. From instrumented crater tests and high-speed motion pictures of the explosions, various experimental checks on the deduced theory of rock breakage are made. The general mechanism of rock breakage by explosives as described in this report is outlined briefly below. The detonation of the explosive charge creates a high gas pressure in the charge hole, which in turn generates a compressive strain pulse in the surrounding rock. This compressive strain pulse travels outward in all directions from the charge hole. Near the charge hole the amplitude of this strain pulse is sufficient to cause crushing of the rock. However, as the strain pulse travels outward its amplitude decays rapidly until no further crushing of the rock is possible. The compressive strain pulse continues to travel outward until it is reflected by a free surface. Upon reflection the compressive strain pulse becomes a tensile strain pulse. As the strength of rock in tension is much less than in compression, the reflected tensile strain pulse is able to break the rock in tension, progressing from the free surface back toward the shot point. In other words, the rock is pulled apart, not pushed apart.

Jan 1, 1957

By Louis W. Cope

Since its discovery, Cuba has been called the “Pearl of the Antilles.” The country remains that, albeit a little tarnished these days. In Havana, many of the buildings are being refurbished, while some new ones are under construction. Since 1991, the laws have been relaxed so that Cuba is developing a mixed economy of central control with free market. Joint venture agreements have been signed with businesses from many countries. This does not include the United States due to its embargo. But even these regulations have been relaxed some.

Jan 1, 2003

By Donlad B. Lindsay

This report describes a field-test program to determine the effectiveness of a polymeric wall sealant to reduce the excape of naturally occurring radio-active gas radon from the walls of an underground uranium mine into the ventilation air. A 75-foot-long, dead-end drift with a surface area of about 6,000 ft2 was used as the test site in which the average natural radon flux from the normally dry rock was 16 fCi/cm2-s. The effect on radon emanation of wetting the walls with water to a depth of 3 inches was tested, after which the rock was completely covered with a coating of dry-mix concrete to provide a base for the sealant, an acrylic latex. Sealant was applied in two coats to about 0.25 mm thick. An overall reduction of average radon flux of about 75 pct was achieved. Radon production and other environmental values were measured continuously and automatically by a Bureau of Mines data acquisition system. A commercial microcomputer was programed to convert raw data to engineering units and to perform other useful operations while recording all data on magnetic diskettes. Direct measurements of radon flux from the rock surface were made by a charcoal adsorption technique.

Jan 1, 1981

By Andre Zingano

The variation in pillar behavior at underground coal mines working in the Bonito coal seam is observed in both research and mining company case studies. There is no consistency in pillar behavior, as it varies from mine to mine. In some cases, it is possible to find rib yields for both excavation modes and pillar sizes. This paper?s objective is to investigate pillar behavior for different load conditions and pillar sizes. Three-dimensional numerical simulation models considering these factors were built. A matrix was then assembled to compare pillar behavior between loading conditions, as well as between different pillar sizes with the same loading condition. The results showed some pillar rib plasticity due to vertical loading and stress relief independent of the pillar size and load. For the same load conditions, the yielding thickness is the same for different pillar sizes.

Jan 1, 2012

By Org de Wet

This paper summarises the strategy for selection between a two module coal plant incorporating large, but less equipment, and a three module coal plant with more but smaller equipment. The two options were evaluated in terms of three main categories: ? Size ? size of the equipment and the effect on the process efficiency as well as the difference in physical dimensions of the plant to accommodate the larger equipment; ? Cost ? capital savings between a two and a three module plant, processing the same ROM (run-of-mine) tons per hour (t/hr); and ? Practicality ? in terms of constructability of the plant, safety of using larger equipment and maintainability of the equipment. Decisions that were taken to reduce the risk associated with size, cost and practicality on the chosen option of a two module plant will be highlighted.

Jan 1, 2006

By C. R. Summers, J. N. Murphy

In response to the Coal Mine Health and Safety Act of 1969, mandatory noise standards have been developed that specify time-noise limits of mine personnel exposure. Most affected by elevated noise levels is the pneumatic roof bolter operator, both in terms of levels near or in excess of 115 dbA and in terms of length of exposure. Therefore, the principal emphasis of this Bureau of Mines report is on pneumatic drill noise control. It is not the intent of this report to suggest any drill redesign; instead, methods are suggested to reduce the noise level by complementing existing machines. An integral muffler system and a separate muffler system were tested in an attempt to lower pneurnaric drill noise levels. Pneumatic drills, when new, operate at about 115 dbA when drilling in sandstone. Using the drill muffler systems, it was possible to decrease the noise level of a 115 -dbA s rope drill to approximately 100 dbA.

Jan 1, 1974

By Bolestaw A. Ktosihski

Preloading of bored pile bases by grouting is an effective way of reducing foundation costs. The bearing performance of a pile may be considerably improved. Various techniques and devices are used. Preloading of a pile base by a special grouting installation is preferred. The grouting device consisting of a U-shaped grouting tube with sleeves and a plastic membrane, separating the tube from the pile concrete, has well proven in Polish practice. The preloading may raise the pile design loads by as much as 30%, and increase their stiffness by 50%, in suitable conditions. The preloading equalizes the deformability of piles in a foundation or a structure. Examples of the base preloading use and load tests of base grouted piles are presented.

Jan 1, 2006

By José Díaz Barrios

El proceso de la explotación minera de la veta Oroya Techo, perteneciente a la mina Casapalca, ha generado un desequilibrio del macizo rocoso, donde la energía que la roca de la caja, piso y techo (volcánicos de la formación Carlos Francisco) no pueden soportar mas allá del límite de su resistencia y deformabilidad natural, es liberada o “compensada” con el estrujamiento plástico de la veta Oroya Techo (estructura carbonatada). En ese sentido, el presente texto describe una manera de cuantificar dicha deformación a través del monitoreo de convergencias, donde se emplea un simple extensómetro de cinta manual y asímediante una análisis estadístico, seleccionar estaciones de convergencia por rangos de mediciones.

Sep 12, 2005

By B. J. Moore

This publication contains analyses and related source data for 310 natural gas samples from wells and pipelines in 16 States. All of the samples were obtained and analyzed during calendar year 1978 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis appara¬tus, which are described in Bureau of Mines Bulletins 4862/ and 576.3/ The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Twenty previous publications have presented the results of 11,573 gas analyses made prior to 197R. The first three, Bulletins 486,4/ 576,5/ and 617,6/ contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960. The other 17

Jan 1, 1979

By W. C. Blanchard

Time Domain Reflectometry (TDR) is a remote sensing technique using active backscatter. This technique is applicable to the testing for faults and multiple partial faults on cable. The battery operated hardware developed on this con¬tract has tailored this technique for testing of mining equipment trailing electrical cables. The processing of-t-he back-scatter is accomplished using a microprocessor. The visual output from the hardware to the operator is; the type, magnitude and distance to the cable fault in a numerical format. This greatly simplifys the use of this techniques for the operator.

Jan 1, 1980

By M. K. McCarter

The history of mining education, like the history of the mining industry, is typified by “boom and bust” cycles. In academia, the perpetual problem can be stated as “too many graduates for the jobs or too many jobs for the graduates.” The deep “bust cycle” that spanned the 1990s through 2003 spawned renewed efforts to eliminate, consolidate, restructure, rename, reinvent or otherwise change mining education to make it (for some) more fiscally or socially acceptable. During this period, a number of mining programs were eliminated, and by the late 1990s senior people in academia and their counter-parts in industry became increasing concerned about the very real possibility that strategic disciplines may disappear altogether. As a result, the Mining and Metallurgy Society of America (MMSA) created an educational committee to explore how industry could help preserve key programs necessary to provide future professionals. Several meetings were held to assess the problems and look for solutions. In 2004, this effort culminated in the first of the “Engineering Education” sessions to be held at the SME Annual Meetings. In response to the information presented in this first meeting, Marc LeVier (then president of MMSA) invited a number of the participants to reconvene the following day. An action plan was formulated and a task force was organized. To more fully represent all industry sectors, SME later that year assumed the sponsorship role for the task force.

Jan 1, 2007

By Kwang ‘Min’ Kim, Paul T. Behum

The Old Bevier Aerobic Wetland in Macon County, Missouri, was constructed between 1990 and 1991 by the Missouri Department of Natural Resources’ Land Reclamation Program for the purpose of treating acid mine drainage (AMD). The principal source of the AMD is from an underground mine that operated during the 1920's through 1950's, which was partially exposed during surface mining in the 1960’s. Limestone bedding of an AMD collection system provided alkalinity similar to an anoxic limestone drain (ALD). Because the original aerobic wetland failed when a critical dilution water supply became unavailable, the total acidity of the AMD overwhelmed the limited neutralization ability of the aerobic wetland. The aquatic vegetation deteriorated and treatment became ineffective. The Missouri Land Reclamation Program with the assistance of the Office of Surface Mining, Mid-Continent Regional Coordinating Center rehabilitated the Old Bevier Aerobic Wetland in 2001, incorporating newer technologies to improve the performance. The new system, Old Bevier II treatment facility, consists of a 2-stage vertical flow pond (VFP) with associated oxidation cells and aerobic wetlands. This paper discusses the performance of this passive AMD treatment system, updating an earlier report. The new treatment system has operated with nearly continuous net alkaline discharge and a high iron removal rate. Treatment improves during warm months when emergent vegetation is fully established and biologic activity is greater. Reduction in system efficiency is evident during winter months.

Jan 1, 2005

By John Capers

•The IME is the Safety and Security Association of the commercial explosives industry in the United States and Canada. •Founded in 1913 •Board of Governors •5 Standing committees- 1. Technical 2. Environmental Affairs 3. Legal Affairs 4. Safety & Health 5. Transportation & Distribution

Jan 1, 2006

By José Mirão, Pedro Madureira, v Costa, Patrícia Conceição

"The exploration of seamounts south of the Azores during the EMEPC/Açores/G3/2007 campaign allowed for the collection of 30 Fe-Mn crusts from the Atlantis, Great Meteor, Small Hyeres, Irving and Plato seamounts, as well as from the East Azores Fracture Zone. These were the first samples of Fe-Mn crusts studied from these seamounts. The Fe-Mn crusts were analyzed using multiple analytical methods.The crusts are fairly homogeneous, showing typical textures for this type of occurrences. The Fe/Mn ratio, patterns and concentrations in rare earth elements, and the great homogeneity of the crusts lead to the conclusion that they have a hydrogenetic origin, precipitating directly from seawater. Although the content in Fe and Mn of the crusts is consistent with data available for the Atlantic, the mean concentration of Co is comparable to the average values for the Pacific. Cu and Ni show lower values than the ones known for the Pacific."

Sep 1, 2014

By Richard Manrique

"La implementación del proyecto de modernización de la fundición de cobre de Southern Peru Copper Corporation requiere cambiar la metodología de funcionamiento de los sopladores para la etapa de conversión. En este sentido, el presente texto señala los aspectos del Sistema de control maestro de reparto de carga implementado en la Fundición de Ilo con excelentes resultados, logrando mejorar el rendimiento de los equipos con una antigüedad de mas de 30 años e invirtiendo tan solo en nuevos controladores en una etapa ligada directamente a la línea de producción. Mantener la variable primaria presión en la red de sopladores, compartiendoóptimamente la carga entre los sopladores en la red, mientras que, se minimiza el riesgo de surge, consumo de energía y los disturbios en el arranque y el paro de sopladores individuales, el sistema deberá ser lo suficientemente flexible que no deberá de perturbarse ante la salida frecuente de los convertidores, es decir deberá de mantener las presiones y flujos a la descarga del manifold ante las variaciones en el consumo de aire todo esto con un mínimo de venteos al ambiente."

Sep 19, 2006

By R. Balia

The upper part of the "Contatto Ovest" orebody, at the San Giovanni Pb-Zn sulphur mine (Sardinia, Italy), is mined by a sublevel caving method. With increasing mining depth, a progressive caving of the hanging wall and discontinuous subsidence occurs. The orebody, which is located very close to the contact between the Cambrian limestones and the Silurian shales, strikes NE-SW for more than 100 m and dips 75-80' NW. The limestone footwall is massive and strong while the hanging-wall consists of very weak shales. The mine considered is located near a town so that the observed subsidence effects must be taken into account for both stability of the nearby railway and houses and morphological and environmental impact. A limiting equilibrium analysis to predict the progress of hanging wall failure with increasing mining depth was used. A suitable computer program was developed for solving the model by a iterative procedure. The progressive hanging wall caving and its consequent superficial effects were predicted perfectly by means of the computer program used and later confirmed by a geophysical test (seismic tomography). Our study ends with a further analysis, carried out using the same procedure, which allows to have a different geometrical situation with the presence of a pillar to protect the mill area.

Jan 1, 1990

Mining and the related extractive and processing industries are chiefly responsible for America's high standard of living. Enormous quantities of sand and gravel, limestone, copper, iron and a myriad of other mineral commodities are required to sustain our growing nation. However, the mineral deposits, both domestic and foreign, are becoming increasingly difficult to find. Adding substantially to the problem, is the fact that the conditions are worldwide. Foreign politics are increasingly affecting mineral commodity availability. Figure 1, taken from Bureau of Mines, "Status of the Mineral industries 1976" illustrates our dependency (in some cases total) on foreign sources for vital mineral commodities. While few nations are capable of exerting an OPEC-like influence on any one mineral commodity, the threat of cartel arrangements and related control strategies is evident. Nationalization of entire industries, once they become self-sufficient, is also exerting a disruptive influence on a large portion of the mineral industries.

Jan 1, 1977

By K. Hardy

As part of Inco's $115 million Fluid Bed Roaster SO2 Abatement Project, a new weak acid treatment plant (WATP) was constructed to treat bleed solutions from the Copper Cliff Smelting Complex gas-cleaning circuits. The WATP produces an iron-arsenic co-precipitate, termed "basic ferric arsenate" (BFA), which requires disposal in an environmentally acceptable manner. Following analysis of many potential options, the short-listed disposal alternatives were: A) Co-disposal of the BFA?gypsum sludge with rock tailings, a portion of which would be used in mine backfill, with the remainder being sent to the tailings area, and B) Co-disposal of BFA?gypsum sludge with pyrrhotite tailings in the tailings area. Testwork showed that the addition of BFA?gypsum sludge to mine backfill samples increased the uniaxial compressive strength (UCS) of the backfill for most samples, especially those at lower binder content ratios. Extensive analysis was conducted on samples taken from the Copper Cliff tailings area, where BFA?gypsum sludge from Inco's Copper Refining Electrowinning Department has been co-deposited with pyrrhotite tailings since 1990. Pore water samples from these areas contained very low arsenic concentrations, indicating that the arsenic had remained stable in that environment. Ultimately, co-deposition with pyrrhotite tailings was chosen as the preferred option for the disposal of BFA?gypsum sludge from Inco's new WATP.

Jan 1, 2006

By Alcides Eloy Cano

Los recursos minerales de un depósito está en función de las dimensiones de la geometría del cuerpo mineral, así como sus reservas minables permiten saber el verdadero valor económico de su contenido. En este sentido, la Geotecnia es una herramienta que define las condiciones de los esfuerzos in situ, predice el comportamiento alrededor de excavaciones subterráneas e interactúa con las labores próximas, así como también la distribución de esfuerzos. Por ello, el presente trabajo señala la aplicación de esta herramienta a una mina subterránea de Oro localizada en el Perú, donde se tiene bloques de mineral económicos, así como señala su accesibilidad con leyes encima del Cut-Off. De forma que se recupera el mineral económico a través de las rutas críticas de carguío, en función de la viabilidad de autosostenimiento.

Sep 12, 2011