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By E. R. Maize

This report is the third of a series on convergence of roof and floor in coal mines and subsidence of surface that accompanies it. The first papery dealt with extraction in a mechanized mine (Montour 10) having relatively short rib lines that retreat rapidly. The second 6/ dealt with extraction in a mine (Crucible) in which coal was loaded by hand and in which the rib lines were long and slow-moving. The present report deals with a mine (Gibson) in which conditions approximated those in the Crucible mine, except that the distance between room centers was considerably less and the pillars were narrower in consequence. Moreover, the average cover was less and the studies were made under the steep hillside of a stream valley compared with a gently rolling surface over the portions of the second mine studied. Gibson mine lies in the east-central part of Washington County, Pa., approximately midway between the Montour 10 and Crucible mines on a north-south line. A cooperative agreement covering the work was made with the Hillman Coal & Coke Co. through W. L. Affelder, vice president. This paper describes the methods used in the investigation, gives excerpts from the data obtained, and offers such generalisations as appear to be justified.

Jan 1, 1940

By G Ma, L Qi, J G. Shellnutt

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Emeishan large igneous province (ELIP) of SW China is host to magmatic Ni–Cu–(PGE) sulfide and Fe–Ti–V oxide deposits which contain economic to subeconomic concentrations of precious and base metals. The formation of a given deposit-type (ie sulfide versus oxide) is thought to be related to the type of parental magma (ie high-Ti versus low-Ti) and the subsequent processes (ie fractional crystallisation and sulfide segregation), which allowed for metal enrichment.We examined the PGE of Baima and Taihe oxide-bearing layered mafic intrusions from the ELIP (Shellnutt, Ma and Qi, in press), and compared them with the nearby Xinjie and Hongge intrusions as well as with the Emeishan flood basalts. The PGE results for the two intrusions are contrasting. The Baima gabbroic rocks are almost PGE-barren (SPGE < 4 ppb) whereas the Taihe gabbroic rocks are variable, but generally much higher in PGE concentrations (SPGE < 2 to ~300 ppb), although the gabbros from both intrusions are enriched in platinum-subgroup PGE (PPGE = Rh, Pt and Pd) relative to iridium-subgroup PGE (IPGE = Os, Ir and Ru). Cu/Zr, Ni/Ir, Y/Pt, Cu/Pd and Ni/Ir systematics suggest that the Baima rocks were derived from a relatively evolved, mafic, S-undersaturated parental magma that was affected by earlier sulfide segregation. In contrast, the Taihe rocks record evidence of both S-saturated and S-undersaturated conditions and that the parental magma was likely emplaced very close to S-saturation. Through comparison of the PGE contents in the Emeishan flood basalts and the Emeishan oxide-bearing intrusions, we provide a self-consistent model for ELIP that the PGE budget in a magma is not strictly controlled by magma series (high-Ti versus low-Ti), but very much by crustal contamination.CITATION:Ma, G, Shellnutt, J G and Qi, L, 2015. Platinum group elements in the Baima and Taihe Fe-Ti oxide-bearing gabbroic intrusions of emeishan large igneous province and problems on propensity of magma series for sulfide- versus oxide-dominated deposit types, in Proceedings PACRIM 2015 Congress, pp 303–310 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Virgil A. Marple

The objective of this contract was to investigate time-integrated and real-time methods for determining the diesel exhaust particulate concentration in underground mines, in particular, coal mines. The microorifice uniform deposit impactor (MOUDI) is recommended for obtaining the time-integrated measurement of the size distribution. The mass concentration of diesel exhaust particles can be obtained from the particle size distribution of mine aerosols. On a mass basis, diesel exhaust particles are primarily in the submicrometer size range while coal dust particles are larger. Size distribution measurements made in the laboratory and in three underground coal mines exhibited two distinct modes with the diesel exhaust particles in the smaller particle mode and the coal particles in the larger particle mode. The point of separation between the two modes occurred in the 0.7 to 1.0 pm size range. The separation was found to be independent of mass fraction of the diesel exhaust particles, particle concentration and sampling site. Methods recommended for further consideration as real-time monitors of diesel exhaust aerosols in mines are photometers and filter pressure drop techniques. A preclassifier would be required in both cases to separate the larger dust particles from the sample. The Metrex Mineral/Diesel Photometer should also be investigated further once the electronics problems are eliminated.

Jan 1, 1986

By James R. Aggson

This Bureau of Mines report describes floor heave ground control problems that have been encountered in a new underground coal mine in West Virginia. Previous experience in the coal seam, the results of physical property investigations, and in situ rock stress determinations are discussed. The apparent cause of the ground control problems is the existence of a high, biaxial, horizontal stress field coupled with a floor member that has time-dependent deformation characteristics, A theoretical analysis of the failure process is developed. The analysis is assisted by finite element techniques. Mine design recommendations based on this analysis are presented.

Jan 1, 1978

By D. Rendini, R. D. Gutridge

INTRODUCTION Gwinnett County, Georgia, is a part of the rapidly expanding metropolitan Atlanta Georgia area. Located approximately 48 km (30 miles) northeast of Atlanta, Gwinnett County has a current population in excess of 600,000 and is projected to reach a population of 1,200,000 by 2025. As a part of the County’s master plan to supply drinking water for the expanding population and to increase system reliability, the Gwinnett County Public Utilities Department undertook the Shoal Creek Raw Water Intake and Pump Station Project. Figure 1 shows a vicinity map for the project. Prior to construction of the Shoal Creek Raw Water Intake and Pump Station Project the County had a single raw water intake to feed water from Lake Sidney Lanier (Lake Lanier) into a filter plant for processing into potable water. This project together with a newly constructed water filter plant provides Gwinnett County additional capacity and system redundancy to prevent interruptions to the drinking water supply. Lake Lanier is a man made reservoir with over 800 km (500 miles) of shoreline and was constructed by the Army Corps of Engineers in the 1950s for hydro electric power generation, flood control, and navigation benefits for the Chattahoochee River. Over time, Lake Lanier has become an increasingly important source of drinking water for the metropolitan Atlanta area. This paper focuses on the primary underground construction and lake tap components of the project including a 42.7 m (140 ft) deep pump station shaft 24.4 m(80 ft) in finished diameter transitioning to a 6.1 m (20 ft) finished diameter shaft, a3.05 m (10 ft) finished diameter by 19.8 m (65 ft) deep intake shaft constructed in an average of 21.3 m (70 ft) of water, and a 190.5 m (625 ft) by 3.05 m (10 ft) finished diameter modified horseshoe tunnel connecting the two shafts. This raw water intake system, in conjunction with the incorporated pump station with 8 pumps and dual1,829 mm (72 inch) pipelines, provides a system capacity of 1,091,062 m3/day(240 MGD) to two water filter plants and is expandable by the addition of pumps to1,500,210 m3/day (330 MGD). Parsons provided design and construction management services for the project. The $29.6 million contract to construct the project was awarded to W.L. Hailey &Company. Notice to proceed was given August 6, 2001 and substantial completion was achieved on January 20, 2004. Value engineering changes adopted for the project contributed to completing the project at a final cost of $28.8 million.

Jan 1, 2005

By M. J. Gilbey

Cross passageways between adjacent tunnels in passenger rail or transit systems may be used during train fire emergencies to evacuate passengers to points of safety in the non-incident tunnel. Rescue trains can be brought into the non-incident tunnel to remove passengers to expedite evacuation times as compared to walking along bench walls to the nearest egress stairs. In cases of multiple train emergencies, the required ventilation capacities can result in high pressure differences between the incident and non-incident tunnels. These pressure differences can make it difficult or impossible for a normal person to open doors of a cross passageway between adjacent tunnels. If opened, the velocity of the airflow through an open cross passageway can reach levels high enough to impede passenger evacuation. This paper describes the analysis of this problem for a sample rail tunnel. A ventilation concept that mitigates the problems of high cross passageway door opening forces and high velocities through open cross passageways is presented.

Jan 1, 2009

"4.1. IntroductionThis chapter reviews the geochemistry of the platinum-group elements (POE) in sulphur-poor silicate rocks, and the limited data on POE in silicate, oxide, sulphide, arsenide and sulpharsenide minerals. The earliest geochemical studies of POE in silicate rocks, minerals and meteorites were carried out mainly by Goldschmidt, the Noddacks and their co-workers, and are reviewed in Crocket (1969). These researchers established the siderophile character of the POE, emphasized the common association of the group with sulphides in ultramafic-mafic rocks and suggested that very low concentrations of POE are typical of sulphur-poor silicate rocks and minerals. Much of these data were for Pt and Pd only and are more than 50 years old. Because of the poor sensitivity typical of the available analytical methods, few reliable data were obtained on silicate rocks in these early studies. Surveys of POE geochemistry demonstrate that the data base for sulphur-poor silicate rocks is very restricted, although considerable highquality data for Pd and Ir have been accumulated (Wright and Fleischer 1965, Yushko-Zakharova eta/., 1967, Mertie 1969, Crocket 1969, 1979, Keays 1981).Two recent publications, Vol. 71, No. 7 (1976), of Economic Geology (An Issue Devoted to Platinum-Group Elements) and Vol. 17, Part 2 (1979), of The Canadian Mineralogist (Nickel-Sulphide and Platinum-Group-Element Deposits), are of special interest. These volumes are clear testimony to the impressive progress made in the last decade toward describing the mineralogical and geochemical aspects of POE ore deposits, but at the same time demonstrate the constraints in modelling POE ore genesis due to our meager knowledge of the. POE content and distribution among minerals in the source rocks of ultramafic and mafic magmas. It is clear that the phases hosting POE in mantle source rocks are poorly understood. Nevertheless, Naldrett and Duke (1980) have shown that the absolute and relative concentrations of POE in magmatic sulphide ores are related to the degree of partial melting of mantle peridotites, and subsequent processes of batch equilibration and fractional segregation of sulphides."

Jan 1, 1979

By Russell R. McLellan

Under the Heavy Metals Program, investigations were conducted at the old Badger dill placer mini in Nevada County California to collect data and information regarding drilling and sampling methods and deposit characteristics. The studies contributed to a team effort by five Bureau of Mines research groups to develop new or improved placer mining technology in the Tertiary gold-bearing channel gravel of northern California. This report describes the techniques used and the results obtained in the sampling and drilling stage of deposit delineation studies that were conducted by the Denver Mine Systems Engineering Group. Sampling included the collection and processing of 400 tons of largo and small volume samples from drill holes, underground workings, surface pits, and blast hole rounds. A total of 355 samples averaging 2,296 pounds per sample provided reasonably accurate data for analysis of the gold distribution. These studies indicate that the bulk of the gold is within 40 foot of bedrock in stacked, lenticular zones of cemented gravel that are largely confined to the relatively narrow, meandering course of the deepest portion of the bedrock channel. Drilling studies involved the testing of three types of truck-mounted drills including rotary, bucket and vibratory, none of which proved to be a completely versatile tool for sampling quickly and reliably both consolidated and unconsolidated gravel.

Jan 1, 2012

By D. Wolfe, R. Cleminson

"The Aurora North mine has been operating for more than ten years, and is the source of over half of Syncrude’s bitumen production. The hydrotransport systems at Aurora experience high rates of wear, and mission lengths on current slurry pumps are nominally 1,500-2,000 hours. Recent work has enabled a better understanding of the significant adverse effect of large particle impingement damage to impeller vane leading edges - which is the known life determining issue for Aurora hydrotransport pumps. A new pump design has been developed and installed at Aurora, incorporating significantly increased impeller diameter and pumping vane lengths. The new pumps are expected to triple Aurora’s previous mission length for hydrotransport pumps. Part II of this paper will share actual hydraulic and wear performance observed in the first several months of operation, and draw comparisons relative to what was expected for these pumps in design / development.INTRODUCTION Slurry Pumps are Critical Equipment at Syncrude Slurry pumps are a key component in Syncrude’s operations. In a typical Aurora application, each 5000 HP pump stage helps move over 8,000 dry tonnes per hour of oil sand, plus an equal volume of process water that has been added to create the slurry. The average impeller life in oil sand hydrotransport service at Aurora has been nominally 1,500 to 2,000 hours, or 12 to 16 million tonnes of oil sand pumped. Generally, the slurry pump application at Aurora has proven very difficult to improve due to the unique combination of high sand abrasivity, 125 mm (5”) large particle top size (lumps), and high flow rate relative to basic pump size; a factor that results in unduly high impeller vane leading edge speeds for the service conditions."

Jan 1, 2014

By William Babcock

Augered, Cast-In-Place (ACIP) piles can be an economical, reliable, versatile foundation system. They have also been a part of projects that were behind schedule and the subject of lawsuits. The ACIP pile is a specialty system that is more workmanship dependent than most deep foundation systems and is especially vulnerable to the problems and abuse of poor specifications and contract language. Many of the original specifications were based on grouting methods, and numerous misconceptions have followed the method. The Deep Foundations Institute (DFI) has been the leader in debunking the mystique that has hovered over the method and attempted to standardize the industry through publication of the manuals describing the method and how it should be inspected. DFI should be applauded for taking the lead and producing a reference document that can be used to educate the specification writers, designers, inspectors, and owners. It must be must appreciated that there have been other organizations that would not acknowledge ACIP piles as a legitimate member of the deep foundation family. Some consultants and designers have gone to the extreme of making it policy to not recommend the method for use. This presentation is one practitioner's view of the causes of problems as they can be traced back to the contractual conditions. It is intended to provide a broader and different perspective than those provided by the technical specialists. It does not necessarily reflect the position of the DFI or any of the organizations associated with the ACIP pile industry. It is intended to further the spirit of partnering on every ACIP pile project, to further the acceptance and promote the use of this unique system, for the benefit of all the parties. It should be recognized, however, that all of the participants can and do play a role in getting a project into trouble. My view is that projects that get into trouble usually have an early flaw that leads the project to the edge, and the project participants blindly follow the original mistake right over the cliff like lemmings. This instinctive reaction may be a survival tactic by going along with the group, because any one party that departs from the program or shows a position of weakness is a candidate for sacrifice.

Jan 1, 1997

By M. Zanini, D. Wong

ABSTRACT: Metals market improvements in 2005 drove the desire to increase nickel throughput and the production of nickel oxide sinter at the Vale Ltd. Copper Cliff smelter. Significant difficulties were encountered due to the unreliable quality of Bessemer matte being produced. Concentrate feed changes and the loss of technical and operational expertise during the previous market downturn contributed to the challenge of making the required improvements. Significant progress has been made in the converter aisle by focusing on employee engagement and standardizing best operating practices for a new generation of skimmers. This paper documents these initiatives and seeks to balance the art and science of converting.

Jan 1, 2012

By Virgil A. Marple

It was the purpose of this contract to conduct research in several different areas of instrumentation used to determine the quantity of respirable dust in the mining atmosphere. One area of research was in evaluation of instruments including several respirable dust monitors, several types of photometers, and a QCM cascade impactor. An instrument evaluation chamber was developed to aid in evaluating the instruments in a dust atmosphere. Another area of research was investigations into new instrumentation concepts, such as a virtual impactor/photometer instrument, a new optical device which can be used as either an optical particle counter or photometer, a new personal respirable sampler, which employs an impactor instead of a cyclone as a preclassifier, and the development of a new cascade impactor, which deposits the particles uniformly on the impaction plate. Another area of research included the use of many of these instruments in two field studies, including a silica sand plant and a tungsten mine.

Jan 1, 1981

Modelling and Optimisation of Direct Reduction of Iron Ore by Coal in a Rotary Kiln

Sep 13, 2010

By P. K. Narasimharaghavan

The major threat to the sustainability of Aluminium Industry is its significant contribution to global warming by way of generation of non eco-friendly gases during its production cycle from Bauxite to the finished product. Though reduction measures are taken in control and effective recovery of values from pot room gases, efforts in use of environment friendly additives in the final products production line is warranted. In this line, the present paper describes our efforts in the use of a new generation refining flux which apart from helping in effective removal of alkali metals, reduction in inclusions and ensure a better metal cleanliness shall also aide in reduction of obnoxious gases generated during the metal refining process prior to casting. The aim of the current work was to reconcile the practical results with the old generation fluxes used. Further improvements to bring in a better metal cleanliness will also be discussed.

Jan 1, 2010

By L. Yuan

To reduce fire hazards from spontaneous combustion of coal in longwall gob areas, a series of computational fluid dynamics (CFD) simulations were conducted by National Institute for Occupational Safety and Health (NIOSH) to model the spontaneous heating of coal in longwall gob areas. The previous modeling results demonstrate that spontaneous heating of coal usually occurred behind the longwall shields and along the face with a bleeder ventilation system. Assuming a stationary longwall face, the spontaneous heating could turn to a spontaneous fire in several days for the most reactive coal under favorable conditions. When the longwall face advances, the spontaneous heating process will be significantly affected. In this study, the effect of longwall face advance on the spontaneous heating in the gob area is investigated using the CFD model developed in previous studies. One longwall panel with a bleeder ventilation system is simulated. The width of the panel is 300 m, while the length of the panel is changed between 1,000 to 2,000 m. The same permeability and porosity profiles are used for gobs with different lengths. The spontaneous heating first develops in the gob when the longwall face is stationary. Then, the face advances at a certain rate. The face advance is simulated as a series of discrete movements, and the effect of the face advance on the maximum temperature developed during the face stoppage is examined. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2009

By L. J. Kane

Conventional methods for determining the size of dust suspended in a gas require that agglomerates (clusters of particles) first be broken into particles, but in evaluating industrial dust-removing equipment the size of the agglomerates as they actually exist in the gas stream is far more important. This paper presents results of an investigation by the Federal Bureau of Mines to develop methods for determining the size of dust agglomerates suspended in a gas stream. The studies are part of the Bureau's continuing research on synthetic liquid fuels. The size and size-distribution of agglomerates as they exist when the gas reaches the filter was determined by using a membrane filter in conjunction with a dust count under a microscope. A membrane filter is a cellulosic sheet about 150 microns thick containing millions of holes per square centimeter--holes of uniform diameter that run directly through the sheet without interconnection.

Jan 1, 1960

By N. Malakondaiah

Several growth chamber and laboratory experiments were conducted to study the germination behavior of plant species on mine spoils and plant growth responses to nutrients on spoils and topsoils. Experiments were conducted to study the germination potential of some native and introduced species under various conditions. The seeds of green needlegrass, side oats grama, thickspike wheatgrass, crested wheatgrass, birdsfoot trefoil and emerald crownvetch were less tolerant, whereas those of alkali sacaton. durar hard fescue, slender wheatgrass, yellow sweetclover and alfalfa were most tolerant to the sodic mine spoil conditions. Addition of leonardite improved the germination potential of some of the poor genninators. Slender wheatgrass and yellow sweetclover were used as test plants to study the fertility status and productivity potential of stockpiled topsoils and spoils collected from Center. Glenharold and South Beulah of North Dakota. The topsoils were neither saline nor sodic but low in N and P. The spoils were neutral to alkaline with SAIL of 12-32, EC of 1.8-5.5 mmhos/cm, Olsen&apos;s P< µ4g/g, and total N <0.07%. Application of N and P together to the topsoils increased the yield of wheatgrass and sweetclover by 88% and 70% of their respective maximum yields, whereas near maximum yields were obtained for both the species by the same treatments to the spoils. The average yields on topsoils were higher than the yields on spoils. The concentrations of major nutrients were higher in plants grown on topsoil, whereas the opposite was true with the concentrations of Mn, Zn, and Cu. Growth chamber experiments were also conducted to study the growth responses of alfalfa, oats and slender wheat grass by the application of Mn and Zn to a sodic coal mine spoil which was previously used for pot culture experiments. Significant growth responses to Mn and Zn were observed in alfalfa but not in oats or slender wheatgrass. Fertilizing the spoil with Mn along with NPK increased the yield of alfalfa to 85% and with Mn + Zn to 99%. Growth responses and plant composition results of this study confirm that the application of major nutrients to spoils can accentuate Zn and Mn deficiencies in some plants.

Jan 1, 1982

By J. Noll

There is a need for direct tailpipe sampling of diesel vehicles in mines in order to determine the effects of an emissions-based maintenance program, evaluate control technologies such as diesel particulate filters and identify the worst diesel particulate matter (DPM) emitters in a fleet of vehicles. therefore, this study examined the performance of three portable instruments: a personal dust monitor (PDM) manufactured by thermo Scientific, a prototype elemental carbon monitor (Airtec) manufactured by FLIr and a prototype Ae91 instrument from Magee Scientific. These instruments were evaluated on the basis of their ability to provide direct reading tailpipe analysis for DPM. It was determined that the average bias of the tailpipe results from the PDM and the Airtec were 3±12% and 4±20%, respectively, when compared to the standard method of determining tailpipe particulate concentrations from a diluted exhaust. It was also determined that the Ae91 instrument correlated with the standard method.

Oct 1, 2013

By Michel Massé

Eleonore Project- Agenda ? Purpose and Technical Overview ? SmartEXEC Control Capabilities ? SmartEXEC System Archetecture ? SmartEXEC System Advantage Eleonore Project- Purpose and Technical Overview ? Control air quality while maintaining target production levels at minimum energy operating cost ? Improve safety, work place conditions and operation flexibility ? Reduce energy consumption and green house gases footprint

Aug 1, 2013

By S. Bhattacharyya

"Coal bearing rocks are low in strength and have geological discontinuities and moisture sensitivity. Roof and rib falls have been a major cause of fatalities in underground coal mines. Mine engineers design ground control plans for regulatory approvals. A number of tools are available from the National Institute for Occupational Safety and Health to design and assess these plans. Quite often there is not enough geotechnical input information available and databases are used. The Appalachian coalfields have extensive scientific studies to provide reliable regional inputs. Coal mines in the western United States and Canada have different geological and geotechnical conditions, and less available data. Use of inappropriate inputs in the tools like Analysis of Retreat Mining Pillar Stability, Analysis of Longwall Pillar Stability, and Analysis of Roof Bolt Systems may result in unsafe designs or over conservative designs. The tools are convenient but thorough understanding of the inputs, calibration with local test results, and operating experience are important for effective designs. The current paper contains examples of difficulties faced during mine planning using the above tools. INTRODUCTION Sedimentary rocks hosting coal are low in strength. Scientific studies have placed the uniaxial compressive strength (UCS), triaxial strength, tensile strength, and shear strength of sandstone, shale, siltstone, and claystone in lower range of strength among engineering materials (1). Coal bearing rocks are most often weakened by the presence of faults, folds, slickensides, bedding planes, fractures, and other geological discontinuities. The host rocks and coal are often moisture sensitive. The geological discontinuities allow water to enter the strata from surface and underground sources. This combination of low strength, structural weakness, and presence of water results in difficult ground control situations for the coal mines. Roof (2) and rib falls have been a major cause of fatalities in the U.S. coal mines. Modern underground coal mines necessitate wide entries to accommodate large production equipment. The gate roads, section entries, and the mains entries of a highly productive coal mine are as wide as twenty feet (6.1 m). The actual intersection width is nearly thirty feet (9.1 m). Adequate ground control is a key to maintain safe production in such mines. Mine engineers and their consultants routinely submit ground control plans to the regulatory authorities. While working out the necessary roof control system the mine engineers are required to demonstrate the adequacy of the proposed system. There are multiple ways to demonstrate this. Some engineers use traditional load calculation approach of roof bolts (3). Some engineers use numerical methods. Yet a large number of professionals resort to a suite of ground control design software offered by National Institute for Occupational Safety and Health (NIOSH) commonly referred to as “NIOSH Ground Control Toolbar.” These software tools are free and easy to download from NIOSH website. The software included in this package are: Analysis of Longwall Pillar Stability (ALPS), Analysis of Retreat Mining Pillar Stability (ARMPS), Coal Mine Roof Rating (CMRR), Analysis of Roof Bolt Systems (ARBS), Analysis of Horizontal Stress Effects in Mining (AHSM), Analysis of Multiple Seam Stability (AMSS), Analysis of Retreat Mining Pillar Stability - Highwall Mining (ARMPS-HWM). These tools are relatively simple to install and use in planning and designing coal mines and prospective coal mines. They accept a number of geotechnical inputs which are collected from either an existing mining operation or from exploratory boreholes. In the absence of necessary input parameters, the programs use default values which are drawn from databases of geotechnical properties built by NIOSH."

Jan 1, 2015