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By Robert A. Cummings

A rock mass classification system has been developed for support estimation in mines using caving methods. The developed system (MBR System) accepts readily-obtainable geotechnical properties, and mining geometry, to develop a rating that permits recommendations for drift support in block caving mines. The data base includes major active United States caving mines. The method is intended to be used for planning and estimating purposes and for preliminary support design. The Manual explains the organization and nature of the MBR System, its derivations, details of required input data, methods for assessing the data and for developing rock mass ratings, and techniques for selecting the most appropriate mine support recognizing mine requirements and desired stability. A worked example is provided.

Jan 1, 1984

By Jewel A. G. Gomes

Green rust (GR) are layered Fe(II)-Fe(III) double hydroxides, having a pyroaurite-type structure consisting of positively charged hydroxide layers and hydrated ions in interlayers. This special feature of GR is very efficient for wastewater treatment as the pollutants are easily taken in or exchanged with the anions in the interlayers. It can be simply and cost-effectively produced by electrocoagulation (EC). Chicken processing plant (CPP) produces large amount of wastewater containing variety of readily biodegradable organic compounds, fats, and proteins. The possible re-use of properly treated CPP wastewater would be economic and environment friendly. In this study, we present our work on treatment of CPP wastewater using EC, specifically for the removal of COD. Analysis of the EC-treated water for reuse in the same plant is discussed considering the U.S.EPA regulations. Two types of EC-reactors were used for this purpose. To better understand the treatment mechanism, EC-floc was also characterized using XRD and SEM-EDS.

Jan 1, 2010

By Yoginder P. Chugh

This study has appraised available deeper soil loosening equipment in the 1-4 ft. depth range, in the U.S. and abroad which has potential for Illinois prime farm-land reclamation. The appraisal was based on written and/or oral contacts with equipment manufacturers, reclamation experts, and visiting with selected equipment manufacturers. The results indicate that several manufacturers in the U.S., West Germany, and England market static and vibratory deeper soil loosening equipment which may have potential for application in Illinois. The pertinent information concerning each equipment with potential is presented in this report.

Jan 1, 1983

By Alexander Siefert, Steffen Pankoke

In the development of commercial vehicles as well as of passenger cars, the effects of vehicle vibrations on operating safety, health and comfort can only be predicted by numerical simulation when appropriate occupant models are available. Such models must be based on human anatomy and have dynamic properties of real humans in order to achieve realistic results. Since human dynamic behavior depend on posture and percentile, the occupant model needs to be adjustable to these parameters with respect to geometry and dynamic properties [1,2]. Dynamic Human Finite-Element-Model CASIMIR CASIMIR is a non-linear, dynamic finite-element-model of the human body. It consists of a dynamic model of the upper torso with head, neck, shoulders and arms as well as of a dynamic model of the lower extremity with pelvis and legs. The most important part is the lumbar area with dynamic non-linear models of the lumbar spine and of back and abdominal musculature. The frequency-dependent characteristics of the intervertebral discs and the effects of muscle activation and non-linear frequency-dependent muscle properties are included. In the latest stage of development, CASIMIR has been equipped with a compliant model of the body surface in the contact areas to the seat. This results in a very realistic transmission of static and vibrational forces into the human body, see fig. 1. Intense model verification and validation has been performed in all stages of model development, starting with validation of small components like intervertebral disc, ending with validation of whole-body-vibrations using measurements of the dynamic mass / mechanical impedance [4]. For an in-detail examination of stresses in the vertebral bodies and discs, a non-linear submodel of the lumbar spine with an increased number of degrees of freedom can be coupled to the whole-body-model, enabling the researcher to examine local effects of vibrations and single shocks on the lumbar materials. [ ] Since it is well known that human dynamic behavior is significantly affected by anthropometric data and posture, CASIMIR can be individualized to the anthropometric status of single individuals or to the mean values for specific percentile groups. Furthermore, posture can be adjusted to the seating conditions applicable to a specific vehicle. Posture modification capabilities include the variation of the lumbar lordosis [3].

Jan 6, 2006

By Georgene Renner

At the beginning of the 1990s, Communism fell and signaled the end of the Cold War. The world rejoiced but also watched and waited to see how those countries would restructure themselves. The 1990 SME Annual Meeting was held at the Salt Palace Center in Salt Lake City, UT. The keynote session featured Alistair Frame, chairman of RTZ; Paul Queneau, professor of metallurgy at the University of Utah; and TS Ary, director of the U.S. Bureau of Mines. The SME Board of Directors voted to hire a Manager of Public Information and Education to be the GEM Program coordinator. This person was to collect and disseminate information that could be used by individual members and Local Sections to interface with government personnel and the general public.

Jan 1, 2007

By V. N. Bryant

"1.0 SYNOPSISThe Colomac property, located 137 miles by air northwest of Yellowknife in Canada's NWT. will recover gold from 10,000 tons per day of open pit ore.The decision to proceed with the project was based on a mineable ore reserve of 16 million tons (including dilution) averaging 0.064 oz/ton. After an in-fill drilling program in the latter half of 1988, Colomac's mineable, proven and probable ore reserves were increased to 28 million tons averaging 0.056 oz/ton of gold.A feasibility study completed by Wright Engineers for Neptune Resources in December 1987 examined the possibility of vat leaching followed by C.l.P. and electrowinning. A second feasibility study completed by Wright in February 1988 demonstrated that a conventional agitated leach circuit using a finer grind justified the higher capital cost of this process. This study was accepted and formed the basis of the project authorization.Preliminary engineering commenced in April 1988 and detailed engineering was started in September of that year with the objective of a mine/mill start-up by early 1990.The short time period available to meet the project deadline was additionally challenging, as site access is either by plane year round, and winter road from early February to late March. Normal lead times for equipment design, specifications, quotations and bid analyses were not possible, if the winter road time-slot was to be met."

Jan 1, 1990

By D T. Froedge

At the 1990 Symposium of the Society of Explosives Engineering, D.T. Froedge, President of GeoSonics Inc., presented a paper entitled "Differential Topographic Vibration Isomapping", which detailed the capabilities of GeoSonics' new Iso-Seismic Service. In this paper Mr. Froedge described how one hundred or &ore free-standing miniature seismographs called Micro-Seis Units, randomly positioned around a blast, could accurately reveal the effects of sub-strata geology on surface ground vibrations. The paper went on to note the "regression analysis of scaled distance versus recorded particle velocity" as being an inadequate predictor of peak particle velocity. This is due to the fact that the calculated "regression analysis" formula for any site is predicted on the wars; case assumption because of a homogeneous and symmetrical sub-strata geology, a condition that rarely, if ever, exists.

Jan 1, 1992

By P. A. Mahanwar

Flyash were melt mixed with nylon 6 at a 30wt% concentration. TYZOR® TPT, a coupling agent, was used to facilitate the link between filler and matrix. The morphological characterization, using SEM, revealed sufficient matrix residue on the filler surfaces thus confirming the strong interfacial bonding between the filler and the matrix on treating. Tensile, impact and the flexural properties of the composites were also improved with the incorporation of coupling agent. As flyash particles tend to impart a grayish color to the plastic, TiO2 pigment was employed to make the formulations aesthetic. The pigment was added to the filled system in 0.1, 0.5, 1.0, 1.5, 2.0 wt/wt ratios. Scattering of incident light and spectral reflectance was higher for smaller particle size flyash. Moreover an increase in the scattering with increase in pigment concentration indicates better dispersion of the pigment, which again is due to the presence of coupling agent.

Jan 1, 2006

By J. P. Harrison, J. A. Hudson

ABSTRACT: Given the current widespread use of numerical models for rock mechanics and rock engineering, and the ‘Technology Road Map’ theme of the Congress, it is timely to consider the key issues in matching numerical models to rock engineering problems. The three main aspects are: a) identifying the mechanisms, variables and parameters that are relevant to a particular rock engineering project; b) establishing the content and mode of operation of a particular code; and c) deciding whether a particular code provides an adequate model for a particular project. We summarise the key issues, highlighting the concept of rock mass domains, validation and the ability to present the results of a modelling exercise. We include three compact numerical modelling case examples to illustrate the points. Finally, we also present a ‘roadmap’ to assist in the process of matching a numerical model to the rock reality. RESUME: Considérant l’utilisation généralisée des modèles numériques en mécanique des roches et en ingénierie au rocher ainsi que le thème du congrès ‘technology road map’, il est opportun d’aborder les problèmes essentiels liés au choix des modèles numériques dans les problèmes ingénierie au rocher. Les trois aspects principaux sont : a) l’identification des mécanismes, variables et paramètres appropriés au projet considéré, b) la définition du contenu et du mode de fonctionnement d’un code numérique donné, et c) la possibilité de décider si un code donné fourni un modèle approprié au projet considéré. Les points clés sont résumés en mettant en évidence les notions de “massif rocheux”, de validation et de capacité à présenter les résultats d’une approche numérique. Nous présentons trois brèves études de cas qui illustrent ces points. Enfin, nous proposons aussi un logigramme pour aider au choix d’un modèle numérique approprié pour représenter la réalité d’un problème au rocher. ZUSAMMENFASSUNG: Im Licht der augenblicklich weitverbreiteten Nutzung von numerischen Modellen in der Felsmechanik and im Felsingenieurbau und unter Beruecksichtigung der Themenstellung des Congresses “Technology Road Map”, erscheint es an der Zeit die Kernprobleme, die sich mit Fragen der Abstimmung der numerischen Modele mit Hinblick auf ihre Anwendbarkeit im Felsingenieurbau beschaeftigen, naeher zu befassen. Die drei wesentlichen Aspekte sind: a) Identifizierung der Mechanismen, Variablen und Parameter, die fuer ein bestimmtes Projekt im Felsingenieurbau von Bedeutung sind; b) die Festlegung des Inhalts und des Modus Operandi eines bestimmten Codes, und c) die Entscheidung darueber ob ein bestimmter Code ein hinreichendes Model fuer ein bestimmtes Projekt ergibt. Wir fassen die wichtigsten Punkte zusammen, heben dabei das Concept der Gesteinsmassen Domaenen (Rock mass domains) hervor, und erarbeiten ihre Beurteilung und die Moeglichkeit diese zu praesentieren in den Ergebnissen einer Model Uebung. Wir schliessen drei Beispiele von numerischen Modellen ein in denen diese Punkte erlauetert werden. Zuletzt schlagen wir eine “Roadmap” vor, um dem Prozess der Abstimmung des numerischen Modells mit der “Felsmechanischen Wirklichkeit” zu unterstuetzen.

Jan 1, 2003

By Cesar Sáenz Acosta

El presente texto señala las mediciones de impactos que se han realizado a los programas de responsabilidad social de una empresa minera. Esta medición se realizó a través del cálculo del indicador “Retorno social de la inversión”, aplicando el modelo SROIM o Gestión del Retorno Social de la Inversión. Los proyectos de RS medidos permiten actuar a las empresas de manera responsable con su comunidad y comprenden: salud y nutrición, educación y desarrollo económico. Asimismo, esta medición contribuye a mejorar la comunicación de los impactos generados y desarrolla una gestión adecuada de estos.

Sep 12, 2011

By Joseph M. Kurtak

The Bureau of Mines is currently conducting a four year mineral assessment of the 5.7 million acre Valdez Creek Mining District in Southcentral Alaska, as part of its ongoing statewide mining district evaluation program. This report is a summary of the 1987 field work, which included the examination of mines, prospects, and mineral occurrences in the study area. Placer gold has been the most important metal produced in the area, and production totaled 161,131 oz, with the majority of the production coming from the Valdez Creek Mine. Lode gold and silver production totaled 1,581 oz and 8,617 oz, respectively and came mainly from the Golden Zone Mine. Varying amounts of other metals, including copper, lead, zinc, molybdenum, antimony, chrome, nickel, cobalt, tin, tungsten and platinum exist in the study area. Occurrences of industrial limestone and coal are also located in the area.

Jan 1, 2011

By M. H. Farjadi, J. Azari

Cost analysis of chrome ore reduction is one of the important issues facing ferrochrome producers in today?s competitive environment. Much of this depends on quality and various ratios in the actual ore. The latter can have a direct bearing on electricity consumption and optimum efficiency of the furnaces. While the industry has been successful in reducing costs by designing larger and more efficient furnaces, the role of the optimum blend of ore has perhaps been given less emphasis. This paper will discuss the general specification and metallurgical characteristics of various chrome ores for producing high carbon ferrochromium on industrial scale. By analysing the results obtained from smelting, including chromium recovery and energy consumption, the determining parameters in total cost of ferrochromium i.e. chrome ore; reductant and energy consumption can be optimized. Our study is based on actual experiences obtained from Faryab Ferroalloy Plant over a period of approximately three years.

Jan 1, 2004

Many investigators measured surface forces between hydrophobic macroscopic surfaces using atomic force microscope (AFM). Some investigators observed long-range attractions and attributed them to the presence of hydrophobic forces, while others suggested that they are artifacts of the nano-bubbles and cavities associated with the hydrophobic surfaces. Still others suggested that the long-range attractions are due to the electrostatic interactions between charged patches present on opposing surfaces and hence are unrelated to surface hydrophobicity. In the present work, we have measured long-range attractions between gold- (or silver-) coated surfaces hydrophobized in potassium ethyl xanthate (KEX) solutions at pH 9.2 under controlled potential conditions. The results of our AFM force measurements are consistent with those of the contact angle and voltammetry experiments, indicating that the long-range attractions are hydrophobic forces.

Jan 1, 2012

How did you get into mining; were you from a mining town or mining family? Not at all. I grew up in northwest Kansas. I liked to hunt and fish, so I thought it would be fun to work for a company that made knives or guns. It seemed like metallurgical engineers would be something those companies could use, so I started in physical metallurgy. I got a summer job at the great Climax molybdenum mine near Leadville, CO shoveling muck onto conveyors. I was hooked. I loved everything about mining, so in the fall, I changed majors from physical metallurgy to mineral processing. For many years you actually discouraged young people from studying the mining disciplines. Could that be right? That’s true.

Jan 1, 2007

By Noel N. Moebs

Bureau of Mines studies of mine roof fall problem in the Pocahontas No. 3 Coalbed of southern West Virgania and southwestern Virginia have established that type and sequence of rock are significant factors in roof competence. The poorest conditions occur where the immediate roof consists of slump structures and slickensided rock. The best conditions occur where the roof consists of a sequence that coarsens upward from shale to massive sandy shale. A small manual of color photographs of rock types was devised to aid in identifying drill cores. Proper identifications should enhance the prediction of areas of potential roof problems in advance of mining.

Jan 1, 1981

By Phillip R. Moyle

Several deposits in the Sheep Hole/Cadiz Wilderness Study Area (WSA) have small identified or potential for undiscovered gold and silver resources. One prospect area is a potential target for molybdenum. Most base and precious metals and one uranium deposit in the study area are of the fissure-filling, contact metamorphic type associated with late stage fluids of the Cretaceous Cadiz Valley batholith. Some evidence suggests limited Tertiary and Quaternary mineralization. Mineral deposits are controlled by faults, shear zones, and joints which strike northwest and dip northeast or southwest. Although undefined, calcium, sodium, lithium, and strontium brines are inferred within the study area. Some potential for oil and gas and geothermal resources is indicated by the interest private industry has shown in the eastern part of the study area. INTRODUCTION The U.S. Bureau of lines and U.S. Geological Survey conducted a mineral survey of the Sheep Hole/Cadiz Wilderness Study Area (p1. 1) which encompasses approximately 205,000 acres (83,000 ha) in south-central San Bernardino County, California. The U.S. Bureau of Mines studied the mineral resources of mines, prospects and mineralized areas; geological, geochemical, and geophysical investigations were conducted by the U.S. Geological Survey.

Jan 1, 1982

By Donald B. Lindsay

A new concept was proposed for a personal warning device for use by miners who may be exposed to health hazards from inhalation of alpha-emitting radionuclides, especially radon-222 and its short-lived daughters. Two successive prototype models of the proposed instrument were designed, fabricated and tested. The Personal Alpha Alarm, in its final form, weighs less than 90 g (3 ounces), and can easily he mounted on a miner's safety cap. It is powered r, by electricity drawn from the cap-lamp battery, and consumes less than 100 n A at 4VDC. It is entirely passive and has no moving parts. Alpha-radiation originating in the air around it is detected by a 5 cm2-area semiconductor-type sensor that was developed especially for this purpose. The presence of alpharadiation in the air is communicated to the wearer by means of a small flashing light-a light-emitting diode-clipped to the brim of the safety cap. When the intensity of alpha-radiation exceeds a predetermined threshold, the flashing mode changes to a continuous illumination, thus providing an alarm signal to the wearer. Because the detector senses all alpha-emitters in the air, including 222Rn, it is not able to measure Working Levels accurately. For its intended purpose, however, which is to give a timely warning of excessive levels (several times the normal control level) of radon and/or radon daughters in an individual's air environment, the Personal Alpha Alarm is expected to be a useful instrument.

Jan 1, 1978

By William C. Cooley

This report includes a review of all relevant data on underground hydraulic coal mining technology collected during Phases I and II of the contract. Data collection and analysis procedures are discussed. Information is included on past and existing underground hydraulic coal nines in the USSR (27 mines), Poland (1 mina), Germany (1 mine), Japan (1 mine), Canada (1 mine), China (1 nine), as well as underground tests conducted in the United Kingdom (2 mines), and in the United States (5 mines). Data is also included on Czechoslovakia and New Zealand. In all operational hydraulic mines, coal is transported underground in flumes. In most cases, bituminous coal is broken by monitors with nozzle diameters larger than 16 mm (0.63 in.) and jet pressures of 50 to 125 atm (710 to 1780 psi). Technical design and performance data are included on all key types of equipment and components which have been developed for, used in, or which could be potentially be used in hydraulic coal mining systems. Data sheets are presented on 180 types of equipment, divided into 24 major categories. Where available, sketches, drawings, photographs, and price estimates are included. Data are included on pitching coal seams in the United States which potentially can be mined by hydraulic methods. Preliminary conclusions are presented, subject to revision as a result of economic feasibility studies to be completed during Phase III. An outline is presented of the final report, which will include economic studies and recommendations for research and development.

Jan 1, 1975

By M D. Hannington

On the southern flank ofLihir Island, a group of three volcanic cones were discovered at water depths from 1000 - 1500 m. The volcanoes are located in a narrow zone of recent seismic activity and elevated heat flow (up to 100 mW/m2). The recovered rocks consist of fresh alkali-olivine basalts, clinopyroxene-rich basalts, and porphyritic phlogopite basalts. One of the volcanoes has a recently erupted ejecta blanket (recovery of warm ash!), containing a suite of abundant mafic to ultramafic xenoliths. These xenoliths appear to represent a unique cross-section of subduction-modified mantle material sampled by volatile-rich primary fore-arc magma during its ascent to the seafloor. The most spectacular finding was the discovery of an active hydrothermal system with associated vent fauna and mineralization at Edison Seamount, and the recovery of unusually gold-rich (up to 43 ppm Au) hydrothermal precipitates in 1050 m water depth at the top of Conical Seamount, only 25 km south of the world-class epithermal Ladolam gold deposit on Lihir. The discovery of submarine hydrothermal vents associated with highly alkaline, quartz-undersaturated fore-arc volcanics represents a significant departure from similar hydrothermal systems on the mid-ocean ridges and in back-arc basins. The high gold grades in hydrothermal precipitates at Conical Seamount may indicate the first documented example of a shallow-marine epithermal system analogous to those known on land, and has important implications' for the gold potential of submarine arc environments.

Jan 1, 1995

By T. Phiri, Antoine Floribert Mulaba-Bafubiandi

Microwave energy has been recently used in minerals processing to speed up the leaching process or to improve the liberation of targeted minerals (Al-Harahshed and Kingman, (2003); Bradshaw et al., (2001)). Applied to the roasting of sulphide minerals, microwaves allow the ?tunning? of calcine types and products quality in addition to the energy savings as opposed to the conventional roasting (Mulaba, 2006). As more than 85% of world zinc is produced through the ?roast-leach-electrowin? route, an attempt was made to optimize cost, energy and product quality for metal extraction process route. The use of microwaves was the alternative process route selected for the optimisation. Pyrite concentrate (0.17% Zn, 0.09% Cu, 35.71% Fe, 43.76% S) and sphalerite concentrate containing 43.81% Zn, 0.37% Cu, 3.86% Fe and 44.39% S were microwave roasted in a multimode cavity of 2.45 GHz with varying power levels and for different durations. The produced calcines were characterized using AAS, XRF, XRD and Mossbauer spectroscopy while the determination of residual Sulphur was used as products quality control tool to ascertain the degree of roasting achieved on the feed. The leachability of the produced calcines in HCl, HNO3, H2SO4 and HNO3 + HCl has been studied in terms of the best leaching yield, process kinetics economics and environmental aspect. With 800 W power for 30 minutes, ZnO and Fe2O3 were formed corresponding to a 70% sulfur removed from sphalerite and 80% from pyrite concentrates respectively. While the roasting of the above concentrates appeared to be a first degree processes, it was noticed that the microwave assisted roasting of sphalerite and pyrite concentrates yielded lower sample surface temperature for a shorter time (i.e.less than 30 minutes) microwave exposition. Longer time (more than 30 minutes) microwave exposure showed a linear increase in temperature in function of power level used. While optimum roasting conditions were found at 800W, 30 minutes, a 10% increase of sulfur removal was noticed while pyrite concentrate was microwave roasted. Sulfuric acid was seen to give higher leaching yield than nitric acid. Zinc dissolution was hindered by the presence of franklinite.

Jan 1, 2007