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By Joseph L. Buckley

A total of 55 conveyor belt fire tests were conducted in the Bureau of Mines Fire Test Gallery, located at the Factory Mutual (FM) Fire Test Center West Glocester, R.I. The objectives of these tests were to: 1) determine the fire resistance and burning characteristics of various conveyor belt materials under simulated mine conditions; 2) provide essential data for designing a reliable bench-scale conveyor belt fire resistance test; and, 3) determine fire test conditions that will discriminate between low, moderate and high fire resistant materials. Belts, representative of those which mold he found in underground coal mines were examined under n umber of experimental conditions which included; ignition intensity; air flow rate; ratio of belt bright (h2) to overall gallery height (h1); exposure time; and, belt width. It was found that fire propagation could be achieved for some "fire resistant" belts (complying with the present Schedule 2G standard for approval) when exposed to an Ignition source of =6000 Btu/min for a 15-min period at a belt height ratio of 01.66. There appears to be a dependency of flame propagation on air flow rates and belt width, although the tests performed do not provide a quantitative trend. Recommendations are made for additional work to resolve some anomalous date and to fill voids in the rest program.

Jan 1, 1978

By C. Y. Liu

This paper principally deals with the application of caisson foundation in the Chinese bridge building industry, the different types of caisson foundation adopted, and their spheres of application. Caisson foundation has been used and speedily developed for bridge works in New China, and a number of new innovations have been made in its design. Especially in deep water foundation, the Nanjing Bridge over Changjiang has attained one of the deepest bridge foundations in the world. There are six types of deep caisson foundation being now in use in China, namely:

Jan 1, 2010

By J. J. Sammarco

Illumination is essential for mine safety because miners depend most heavily on visual cues to detect hazards associated with slips/trips/falls and powered haulage. The National Institute for Occupational Safety and Health (NIOSH) is conducting mine illumination research to improve miner safety by enhancing a miner?s ability to see mine hazards. Thus far, 16 papers have been published covering diverse topics such as cap lamps, machine-mounted lighting, glare, lighting maintenance, and light-emitting diode (LED) technology issues. NIOSH has also developed an LED cap lamp, LED area lighting, and a Visual Warning System (VWS). This paper provides an overview of the improvements from NIOSH-developed lighting that include: 94% faster trip hazard detection with the NIOSH LED cap lamp; 79% faster peripheral motion detection to detect pinning/striking hazards; no increase in glare; 71% faster machine movement hazard detection with the VWS. Current research is described concerning an LED cap lamp for metal/nonmetal miners, illumination for refuge alternative deployment and inspection, and whether lighting could be used to improve miner escape and rescue in smoke. Lastly, future possibilities of using lighting to improve miner safety are described.

Feb 27, 2013

By F. J. Sotillo

The reduction in energy consumption has been always important for beneficiation plants. Also gravity separation processes have gained lately great importance due to environmental concerns, especially in the gold and silver Industries. In this sense, the paper point out how to reduce the energy consumption in grinding, and increase efficiency in both grinding and gravity separation are of utmost importance to optimize the use of the country’s resources. For these purposes, chemical additives, such as rheology modifiers have shown great potential, and deserved careful consideration.

Sep 9, 2007

By Tony A. Rorke, Joe R. Brinkmann

The application of instrumentation to better understand and improve production blasting is one of the most fruitful areas of explosives and blasting research. The majority of instrumented studies of production blasting have relied on the extrapolation of far field measurements to postulate blast performance in regions of interest closer to the charge where rock breaking takes place. However, the nonlinear and dissipative nature of the quantities being measured raises serious questions as to the accuracy and validity of such extrapolations.

Jan 1, 1991

By A. D. Pelton, Y. -B. Kang, S. A. Decterov

Computerized thermodynamic databases for solid and liquid metal, slag and solid oxide phases in the Al2O3-CaO-CoO-CrO-Cr2O3-FeO-Fe2O3-MgO-MnO-NiO-SiO2-S system have been developed by critical evaluation/optimization of all available phase equilibrium and thermodynamic data. The databases contain parameters of models specifically developed for molten slags, liquid steel and solid oxide solutions such as spinels, pyroxenes, olivine, monoxide (wustite, periclase, lime), corundum, etc. By means of the optimization process, model parameters are found which reproduce all thermodynamic and phase equilibrium data within experimental error limits. Furthermore, the models permit extrapolation into regions of temperature and composition where data are not available. The databases are automatically accessed by user-friendly software that calculates complex equilibria involving simultaneously slag, metal, refractories and gases, for systems with many components, over wide ranges of temperature, oxygen potential and pressure. A short review of the available databases is presented. The critical evaluation/optimization procedure is outlined using the Al2O3-CaO-FeO-Fe2O3-SiO2and Al2O3-CaO-MnO-SiO2systemsas examples. Several applications of the databases to deoxidation of iron and to inclusion control in steel are discussed. Keywords: thermodynamics, phase equilibrium, phase diagrams, databases, ferrous metallurgy, steelmaking, inclusion control, slags, oxide systems.

Jan 1, 2004

By William F. Daly, William H. Hansmire

Installation of initial tunnel support is often the most uncertain element of work in the design of, and a contractor bidding on, construction of a rock tunnel. The risks the construction contractor and owner assume are delineated to a great extent in the technical specifications portion of the contract documents. It is intended that this paper identify current practices for specifying initial tunnel support and the impacts each case has on the assignment of risks associated with providing the initial tunnel support. Examples of recently completed tunnel designs are given.

Jan 1, 1985

By K. Pathak

Loaders and dump trucks are the most commonly used surface-mining equipment. Negligence of the safety-engineering aspects of dump trucks may result in serious accidents in a mine. A reduction in the risk of an accident due to the deployment of trucks can he achieved by engineering analysis, risks assessment, improved safety features, active safety devices, condition-based maintenance, in-built protection systems, etc. This paper presents some cases of accidents in Indian surface coal mines and advocates a systems approach to safety.

Jan 1, 1999

By Jorge Oviedo

La planta de lixiviación, extracción por solventes y electrodeposición (L-SX-EW) de Southern Perú es una operación hidrometalúrgica dedicada a la lixiviación ácido – bacteriana de los botaderos de mineral de baja ley de la Mina Toquepala, para la producción de cobre catódico de la más alta pureza. En ese sentido, el presente trabajo describe la evolución del sistema de control y supervisión de esta planta minera en Cuajone. Para ello, dicha planta debe tener una actualización constante de sus sistemas de control y ser capaz de cambiar con la velocidad a la que avanza la tecnología de Control de Procesos. Asimismo, debe contar con personal calificado que permita el desarrollo y modernización de los sistemas sea continuo y no dependa solo de expansiones y ampliaciones ejecutadas por especialistas externos. De forma que este software de supervisión, no solamente considera la capacidad de operar la planta, si no debe ser una ayuda tanto para el operador como para brindar información en la correcta toma de decisiones.

Aug 25, 2002

By Richard A. Winters

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 49,875 acres of the 54,833-acre Big Jacks Creek Wilderness Study Area (ID-111-7C) in order to evaluate the mineral resources. The study area is located in Owyhee County, ID, about 15 miles southwest from Bruneau, ID. No mining districts are in the study area, but part of one placer claim, located in 1924, extended into it. The northern portion of the area was covered by oil and gas lease applications; all were cancelled prior to 1985. No economic concentrations of minerals were found in the study area. INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of the Big Jacks Creek study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Although the immediate goal of this and other USBM mineral surveys is to provide data for the President, Congress, government agencies, and the public for land-use decisions, the long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

The Mining Foundation of the Southwest will host its 24th Annual American Mining Hall of Fame Awards Banquet at the Tucson El Conquistador Golf & Tennis Resort in Tucson, AZ on Saturday, Dec. 9. The Mining Foundation of the Southwest is a non-profit organization whose objectives are public education about the mineral industries. It also recognizes outstanding accomplishments in and contributions to the fields of fuel and mineral resources.

Jan 1, 2006

By John Rusnak, Christopher Mark

Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are dependent upon rock type. This study involved the extensive load frame and point load testing of coal measure rocks in six states. More than 10,000individual test results, from 908 distinct rock units, were used in the study. Rock lithologies were classified into general categories and conversion factors were determined for each category. This allows for intact rock strength data to be made available through point load testing for numerical geotechnical analysis and empirical rock mass classification systems such as the Coal Mine Roof Rating (CMRR).

By Leslie F. Sawatsky

Raw water import requirements for oils sands mines depends mainly on factors such as ore processing rate, ore material characteristics, tailings processing technology, tailings storage systems, process water storage operations, the phase of tailings production, and non-recoverable seepage losses from tailings ponds. These factors can be readily quantified to calculate raw water import needs. Nevertheless, mine water balance continues to be misunderstood by some regulators, stakeholders and possibly even mine operators. Confusion over consumptive uses has led to a focus on recycling which is not necessarily applicable to a closed circuit water management system. Some water conservationists focus attention on raw water intake rules instead of the technical decisions that control consumptive uses. Typical oil sands mine water balances for various types of tailings operations, are analyzed to illustrate the effect of controllable and uncontrollable parameters as well as major options that need to be explored for reducing water demand. Uncontrollable parameters including tailings fines content, oil content of ore, connate water, mine depressurization water inflows and surface water hydrology. Controllable parameters include storage operations, advance water supply ahead of mining operations, type of tailings operation, net tailings pond seepage losses, and tailings impoundment operations. Potential reductions of raw water supply rates may be obtained by providing greater on-site storage to attenuate fluctuation in water demand, advance water accumulation prior to mine start up, early commencement of CT operations, thickened tailings disposal and paste technology. Water conservation measures should be focused on reducing on-site process water storage and water content of tailings material.

May 1, 2004

By Y. L. Su

Deterministic and stochastic simulation were combined to develop a computer model of an open pit mining system using bucket wheel excavators and related materials handling equipment. The model is closed and dynamic in the sense that information is fed back to control activities at various levels and reservoirs. The results of interaction between unit operations in one time interval determines overall system behavior for the next interval. Equipment performance curves and system profile characteristics rather than time studies are applied to determine the operation of each activity at any time period. For that part of system where performance is dictated by a random variable~ subjective probabilities are employed. Two stages of research were considered to formulate this model. Stage one involved the formulation of equipment sub-assemblies for the sequence of equipment moves along with related assignments and routines for information retrieval. The second stage of research combined all sub-assemblies into an integrated open pit mining simulator. The model is not tailored for any specific open pit operation but is readily adaptable to any system of surface mining including operations having a high degree of complexity. Questions answered by the model include: 1) system design and selection of equipment for a new mining operation; 2) analysis of existing operations for possible changes, additions or general

Jan 1, 1971

By S. Krukowski

Iodine is a bluish-black, crystalline solid with sub-metallic luster, and has a specific gravity of 4.93. It volatilizes (sublimates) at ordinary temperatures into a blue-violet gas that has an irritating odor. Iodine is the least active of the halogens, all of which readily displace it. Only slightly soluble in water, iodine also dissolves in carbon disulfide, carbon tetrachloride and chloroform, giving a deep violet solution. The primary sources for iodine production are sub-surface brines associated with petroleum and natural gas deposits, and as a byproduct from nitrate deposits in Chilean desert caliche. The largest source of iodine is seawater which contains 0.05 ppm, or about 31 Mt (34 million st). Seaweed of the family Laminaria can extract and accumulate up to 0.45 percent iodine on a dry basis. Seaweed was an important source of iodine prior to 1959. However, it remains a significant source of iodine in the diets of many populations throughout the world.

Jan 1, 2005

By Aleksandar D. Bugarski, Robert J. Timko

Despite extensive research efforts conducted in the past decades, occupational health risks associated with exposure to nano and ultrafine aerosols emitted by diesel power equipment are still not completely understood. The complexity of physical and chemical properties of diesel aerosols, constantly changing with the implementation of advanced diesel emissions control technologies, make this task rather challenging. The objective of this paper is to identify and characterize nanometer and ultrafine aerosols emitted by diesel engines in the underground environment and evaluate the effects of selected contemporary control technologies on physical properties, chemical composition, and in-vitro toxicology of diesel aerosols. The physical and chemical properties of the nanometer and ultrafine diesel aerosols are to be characterized through a test series in the NIOSH Lake Lynn Laboratory experimental mine. The crucial part of the study has been development of a facility that allows researchers to generate field results with precision and accuracy characteristics of a laboratory environment. The knowledge obtained from this study should strengthen our understanding of the health implications related to exposure to diesel particulate matter and aid in assessing the potential of various control technologies for reducing this exposure.

By A. B. Cecala

Over the past decade, a substantial effort has been made to improve the air quality inside enclosed cabs of both underground and surface mobile mining equipment to reduce respirable dust exposures to the equipment operators. As part of this effort, the National Institute for Occupational Safety and Health, (NIOSH) completed a comprehensive laboratory study which determined the significant factors for cab filtration and pressurization systems. From this information, a major underground mining equipment manufacturer designed a filtration and pressurization system which was incorporated into the enclosed cabs of its equipment. A long-term evaluation was performed on the effectiveness of this filtration and pressurization system to improve the air quality in the enclosed cabs of two different pieces of equipment, being a face drill and a roof-bolter machine, at an underground limestone mine. This long-term evaluation demonstrated a significant reduction in dust levels comparing outside to inside cab respirable dust concentrations. During this evaluation, a modification to remove one of the filters on the roof-bolter machine simplified the design without sacrificing the system?s efficiency. Testing using particle count instruments performed during non-production time periods on both pieces of equipment indicated Protection Factors greater than 100 when comparing respirable-sized dust particles inside the enclosed cab relative to outside.

Jan 1, 2012

By Y. P. Chugh, J. Ma

Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short period of time. It is now a serious challenge to cope with ground control problems such as roof falls, face and floor failure, and excessive shield loading as fast as possible to minimize production and monetary losses. In Illinois coal mines, the existence of weak floor strata blow the coal seam may pose additional problems related to floor heaving, shield base punching, and associated roof and face falls. In this study, the effects of weak floor on longwall ground control are analyzed using two-dimensional finite element models. A two-leg 635.6-ton (700-short-ton) yielding capacity shield is included in the models to evaluate the effects of different thickness and material properties of the weak floor. The study indicates that the thickness and material properties of weak floor have significant effects on shield loading, the distribution and intensity of front abutment stress, failure zones in the surrounding strata, roof-to-floor convergence, and floor punching by the shield base.

Jan 1, 2000

By Zhitao Ma

The Cast-in-place Concrete thin-wall Pipe pile, referred to as PCC pile, is a new kind of pile for soft ground improvement. In this paper, firstly, the general introductions of the new pile technique, mainly including the technique principle, the structure of pile-driving machine, and the technological process were given, then based on the results of in-situ static lateral loading test, the pile lateral capacity, the relationship of load-deflection of pile at the ground surface, the lateral deflections versus depth and the soil reaction along the pile shaft were analyzed.

Jan 1, 2006

By S. K. Oraee

Managers always look for systems with minimum hazards. The hazards create problems for performance of projects. The largest and most important hazards of working underground mine can be related to health, safety and environmental, because if one of these sectors be in hazard, maybe lead to close mine. Failure mode and effects analysis (FMEA) is a widely used quality improvement tool to identify the potential failure modes for measuring reliability of a product or a process. FMEA is performed by developing a risk priority number (RPN), which is the product of severity, occurrence, and detection ratings. On the other hand, with regard to uncertainty in the decision-making, fuzzy theory will be able to model this uncertainty. Fuzzy FMEA provides a tool that can work in a better way with vague concepts and without sufficient information than conventional FMEA. This article by using Fuzzy FMEA and based on HSE criteria evaluate hazards of Parvade No. 1 Mine in Tabas Coal Mine. The results demonstrate the most hazardous parameter is rock burst in this mine.

Jan 1, 2011