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By Thomas P. Mucho

Cable bolts are emerging as the newest ?twist? for roof support in U.S. underground coal mines. For decades cable bolts installed in underground metal mines in the United States and Canada used cement-based grouts for anchoring. The cement anchoring process, because of the time and expense for installation, made cable bolts impractical for use in coal mines. Today, the introduction of resin-anchored cable bolts provides a system more consistent with tradi­tional U.S. coal mine roof bolting practices and requirements. Expecta­tions are that the utilization of cable bolts for a number of U.S. mining applications will expand, particularly in coal mining.

Jan 1, 1998

By J. F. Jackson, R. W. Mau

"The first commercial installation in the mineral industry of the ""Verti-Press"" pressure filter was made by Falconbridge Limited at the Strathcona Concentrator to filter copper concentrate. The filtercake produced contains 6 - 7% H2O, an improvement from the 12 - 13% H2O produced by an internal drum filter, at rates of up to 20 t/hr. A novel slurry feed system incorporates a hose pump and a pressurized slurry accumulator.INTRODUCTIONIncreased copper production from Falconbridge Limited operational mines in the Sudbury Area has exceeded the current refinery capacity. A copper concentrate has been produced to overcome this constraint and has been shipped to custom smelters either as a slurry or as a 12 - 13% moisture filtercake utilizing an internal drum filter.With the treatment of the new Deep Copper Zone from the Strathcona Mine, copper concentrate production was forecast in excess of the installed dewatering capacity. The filtercake was too wet to transport by truck and the custom smelter refused to handle this product at the truck unloading site. The filtercake had to be trucked to a rail spur and transloaded into gondola cars. This system was expensive, incurred unaccountable losses and the concentrate was assessed a moisture penalty.To reduce the concentrate moisture content to permit direct shipment by truck, two basic systems were available; vacuum filter followed by a thermal dryer or a pressure filter. Past experience with the high capital and operating costs of dryers led Falconbridge to closely examine the pressure filter alternative.COPPER CONCENTRATE PRODUCTIONThere are two separate circuits at the Strathcona Mill; one treating nickel ore and the other treating copper ore.The rougher concentrates produced by both circuits are conditioned with lime and cyanide before the copper-nickel separation in a flotation columns. The concentrate consisting of cha lcopyrite with mi nor cubanite is very clean as shown in Table I. Currently 50% of the copper in the plant feed reports as copper concentrate, in the past, this has been as high as 70%."

Jan 1, 1990

By Lloyd Williams

1. This investigation shows that the Poplar Creek is the most important bed in Scott County from a production standpoint. Although the Poplar Creek bed contains the largest reserve, the Big Mary has a larger recoverable reserve. Estimates of reserves also have been made for the Pewee, Red Ash, Windrock, Upper Pioneer, Jellico, and White Oak beds. 2. Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 143 million tons as of January 1, 1954. Of this total, 74 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

By David A. Monaghan

This report describes the results of a 2-year investigation of extensible face ventilation techniques and systems for use at the working face in underground coal mines. The goal was to provide a safe and convenient method of maintaining the extensible system within 10 feet of the face, thereby ensuring good ventilation. A summary of approximately 20 extensible ventilation systems proposed or tried in the past is included for reference, together with a detailed description of the design, construction, and underground testing of a new extensible brattice panel and a new fiberglass duct system. The extensible brattice system utilized a special panel which could be pushed forward as the miner advanced. Brief testing in three mines revealed some conflict with the mining cycle and led to recommendations for two improved designs. The extensible duct system was designed for a Goodman borer and utilized a telescoping tube on the left side of the roof, so that it could be extended without interfering with the miner operator. For mine sections with right-hand return ventilation, a special flat tube section is used to cross over the entry. Underground testing showed substantial improvement in face ventilation without interfering with production.

Jan 1, 1976

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Robena No.4, located near Waynesburg, Pennsylvania. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. With present instrumentation, the spectrum can be covered from 40 Hz to 400 kHz. It is recorded using broad-band analog magnetic tape, and the noise data are later transformed to give spectral plots. The other technique records noise envelopes at several discrete frequencies for a sufficient amount of tine to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and amplitude probability distribution plots. The general results are that at frequencies below 10 kHz, power line noise within the mine is severe. Impulsive noise is severe near arcing trolleys, and at lower frequencies near any transmission line. Carrier trolley phone signals and harmonics are strong throughout the mine whenever the trolley phone is in operation. Additional information beyond that included in this report may be obtained from the authors, who are with the Electromagnetics Division of the National Bureau of Standards.

Jan 1, 1974

By M. Deutsch, E. González, M. Williams

"Uncertainty exists in ultimate-pit limits due to geologic variation and unpredictable economic landscapes. In this work, we show how this uncertainty affects the ultimate pit and how it can be analyzed to improve the mine planning process. A stochastic framework using geostatistical simulation and parametric analysis was used to model the effects of geologic and economic variations on ultimate-pit limits and overall project economics. This analysis was made possible by a new pit optimization implementation that can be automated and set up to calculate ultimate pits for hundreds of different scenarios in a matter of hours. Quantifying ultimate-pit uncertainty early in the mine planning process allows mining engineers to make informed decisions regarding infrastructure placement and to mitigate the possibility of incurring substantial costs to relocate critical mine facilities. Resumen ¦ Existen dudas sobre los límites del pit final por causa de la variación geológica y lo impredecible de los paisajes económicos. En este trabajo les mostramos como esta incertidumbre afecta el pit final y como puede ser analizada para mejorar el proceso de planificación de la mina. Se usó un marco estocástico con simulación geoestadística de análisis paramétrico con el fin de poder hace la modelación de los efectos de las variaciones geológicas y económicas en los límites de pit finales y proyectos económicos en general. Este análisis fue posible gracias a una nueva implementación de optimización de pits que puede ser automatizada y configurada para calcular pits finales para cientos de escenarios diferentes en cuestión de horas. La cuantificación temprana de la falta de certeza en pits finales durante el proceso de planificación permite a los ingenieros de minas tomar decisiones informadas en lo que respecta a la ubicación de infraestructura y en la mitigación de posibles costos sustanciales por causa de la reubicación de instalaciones clave de la mina."

Jan 1, 2015

By Vincent Jue

In December 2009, the Italian High Speed Rail Network AV began running over the full 1000 km system length from Turin, at the foothills of the Alps to Salerno, on the seacoast south of the volcano Mt. Vesuvius. It runs through Alpine rivers, highly seismic active zones, mountains, river plains, and through some of the most densely populated areas in Europe as well as some of its most expensive real estate. The Italian High Speed Network?s technical/economic constraints and its regulatory/socio-environmental concerns well may mirror similar obstacles set to confront the nascent California High Speed Rail Program. The two types of constraints must be dealt with together to reach the best construction solution. It is estimated that more than 20% of Italian High Speed Rail Network costs were spent on ground engineering including over 150 km of tunnels, 200 km of viaducts and bridges and 650 km of embankments and trenches. However, it also is estimated that 25% of costs were spent on social and environmental integration of the new rail lines including over 6 square miles of green offsets, 160 km of anti-noise walls, and 300 agreements for socio-environmental work. This paper will look at four examples of innovative ground engineering solutions, each with its own intricate set of constraints: ? Foundation system for viaducts across the ?Po? and ?Ticino? rivers. ? Soil consolidation under railway embankments ? Requirement of short tunnels for physical and environmental reasons ? Construction of railway stations in a confined right of way

Jan 1, 2010

By K. Heatwole, D. Shier, A. Davis, J. Kidder, S. Sunkavalli

"Acid rock drainage (ARD) is produced when sulfides are exposed to oxygen and water. Oxidation reactions typically result in a depression of pH and leaching of solutes and metals. Many oxidation models have been developed based on oxygen diffusion, but in environments with high permeability, other transport processes (i.e., convection and advection) can play an important role. Multiple sulfide mineral phases with differing oxidation rates should also be incorporated. WROC, a finite-difference model, was developed to account for these factors in predicting ARD. The program includes sulfide mineral oxidation using a shrinking core mechanism, heat transfer by conduction, heat of reaction and oxygen transport by diffusion and advection. The model was validated using data from the literature. After validation, the WROC model was used to simulate several different waste rock scenarios, including different forms of sulfide mineralization and the effect of implementing a waste rock cover. The results demonstrate that including specific sulfide mineral phases can have a significant effect on oxidation and that implementation of a cover can also aid in reducing waste rock oxidation.IntroductionAcid rock drainage (ARD) is a notable environmental concern in areas where rock or other material with acid generation potential is disturbed. ARD is defined as drainage that occurs as a result of sulfide oxidation in rock exposed to air and water. ARD is characterized by low pH, elevated metals concentration (especially aluminum, iron and manganese), sulfate and high total dissolved solids. The low-pH water that results from acid generation is capable of solubilizing heavy metals contained within the rock. The principal sulfide mineral in mine wastes is pyrite (FeS2). Pyrite oxidation is complex and can involve chemical and biological reactions. Oxidation of pyrite by atmospheric oxygen produces one mole of Fe2+, two moles of SO4 2- and two moles of H+ for every mole of pyrite oxidized, as described by Eq. (1)."

Jan 1, 2015

By M. D. Aldridge

The results of a four-year research effort aimed at developing a practical and effective electronic system for monitoring safety conditions throughout a coal mine by displaying, at a central location, remotely measured parameters are described. This document reports on the design details of the sensor packages and the data processing program used in an experimental monitoring system. The results of special ventilation monitoring experiments and several sub-system considerations are also described.

Jan 1, 1974

By Jeffrey A. Shibe

A prototype Fire Safety Evaluation System has been developed and is ready to be evaluated by a Peer Consulting Panel and for performing field tests. The system can be used to determine combinations of widely accepted fire safety equipment and under-ground coal mine features that provide a level of safety equivalent to those required by the Code of Federal Regulations-Title 30 for underground coal mines. In this evaluation, equivalent safety performance is gauged in terms of overall level of safety provided rather than by a component by component comparison.

Jan 1, 1987

By Wang Zhi

High-Mg-content concentrates are usually treated in Jinchuan flash smelting Furnace. Because the viscosities of high-Mg-content slag is very high, the operation of flash smelting becomes very difficult. To solve this problem, the viscosities of the semi-synthesized FeO-MgO-Si02 slag of different compositions were measured. The results showed that when in the slag the weight percentage of MgO [m(Mgo)] is 6-10%, the ratio of the weight percentage of iron to that of Si02, m(Fe)/m(SiO2) is 1.1-1.4 and the temperatures are within 1473?1773K, the slag viscosities increased with the increase of m(Mgo) and m(Fe)/m(sio,). When m(Mgo)<6%, the smelting temperature should be controlled at I 300°C in order to to keep the smooth operation. When m(Mgo» 10%, the temperature should be kept above 1633K. When the content of MgO is higher, a lower viscosity slag ean be produced by decreasing the ratio of m(Fe)/m(sio,). The appropriate ratio of m(Fe)/m(sio,) for Jinchuan flash smelting furnace is about 1.2.

Jan 1, 2003

By Hayel M. El-Naggar, Sherif A. Akl

Although grouted piles have been used for several decades since the idea was proposed in the 1970s, their design is mostly based on experience and unpublished proprietary methods. There is little research on grouting drilled shaft tips and even less on grouting shaft sides. This paper presents the analysis of 4 instrumented pile loads tests on base and shaft grouted piles from different sites in Egypt; with emphasis on one of the tests, to demonstrate the analysis process. The data from the tests are analyzed to model the development of unit side friction (USF) with relative displacement. A numerical model using the finite element software PLAXIS is used to investigate the effect of grouting on the surrounding soil stress state. The paper combines the observations from full scale pile load tests and results from the numerical model to suggest an idealized behavior of side friction development with relative displacement of the grouted part of the shaft. The suggested model considers an envelope of Unit Side Friction (USF) with relative displacement, initially dominated by the grout resistance then at higher relative displacements, the friction with radially pressured soil takes over. The grout provides very high USF values up to a relative displacement of 2mm. Then, the USF drops to a typical pile soil side friction behavior; however, this friction is affected by the contact stress between pile and soil, which significantly increases due to compaction grouting. INTRODUCTION Base and shaft pile grouting has been significantly developing in recent years to accommodate the unfavorable conditions in major projects such as the high loads in high rise building and founding on problematic soil formations. Grouting aims to decrease settlements and increase the capacity of the pile under axial load. The technique is first introduced by Kraft (1974) but gained popularity in the 1980s. Typically there are two types of grouting; compaction, and permeation. Compaction grouting is more common in pile foundations practice, and many researchers have provided case histories of pile load tests on base grouted piles and base and shaft grouted piles (Gouvenot and Gabaix,1975; Stocker, 1983; Ghazali et al., 1988; Fleming, 1993; Kusakabe et al., 1994; Robson and Wahby,1994; Joer and Randolph, 1998; Hamza and Leoni, 1998; Mullins et al. 2000; Littlechild et al., 2000; Suckling and Eager, 2001; Dapp and Mullins, 2002; Ho, 2003; Fu and Zhou, 2003; Brettmann and NeSmith, 2005; Ruiz, 2005; Mullins, 2006; Dapp and Brown, 2010; Beadman et al., 2012; Nguyen et al., 2013; Miller et al., 2013; Sinnreich and Simpson, 2015; Hui and Lin, 2015). Compaction grouting is meant to densify the soil around the pile and below the base rather than permeate this soil and increase its cohesion. Research showed that grouting increases the capacity of the piles by a factor of 2~5. The variation in capacity increase depends on pile type, grouting process, and especially grouting pressure. Although there are many case histories of pile load tests on grouted piles but there is no well-defined agreed-upon method to predict grouted pile capacity as typically done in ungrouted piles. Few lab experiments discussed the shaft grouting effects on the soil especially the compaction grouting. The experiments concluded that the compaction grouting forms a homogeneous layer between the pile and the soil, and a residual effective stress is achieved simultaneously with a significant densification of the soil around the pile with noticeable decreasing in void ratio. (Fattahpour et al., 2015; Wang et al., 2015). Recently, studies used numerical analysis to investigate the behavior of the grouted piles and the changes in the surrounding soil (Chiang et al., 2013). That study presents a simulation of the base pressure grouting with a simple FE model and predicts the reduction of the pile settlement by 10 to 20%. Another numerical study using a complex model conducted by Zhou et al. (2017), pr

Jan 1, 2018

By S. Nagamatsu

Alumina supported gold catalyst prepared by spray reaction method (spr) provides gold particle with about 20 nm of diameter. The gold particle size is larger than conventional gold catalysts. However, the spr catalyst shows higher catalytic activity for NO-CO reaction. In the present paper, we have discussed the local structures of spr-Au/Al2O3 catalyst by using Au L3-edge XANES spectra. In order to investigate the local structures of Au-sites, multiple scattering approach to XANES analysis was applied. Calculated Au L3-edge XANES spectra for fcc-Au and Au2O3 were in good agreement with the observed spectra. XANES spectra for spr-Au/Al2O3 were characterized by 4 types of Au sites (bulk, interface, surface and peripheral). In this case, almost all gold sites (> 90 %) are bulk site. The other sites are less than 10 % of gold particle. However, the experimental and the calculated results of Au L3-edge XANES spectra for spr-Au/Al2O3 require about 30 % of gold oxide or hydroxide. Bulk of Al2O3 contains a certain number of gold nano-particles, which was incorporated in the bulk Al2O3 support. In the interface area, gold oxide forms a few layers. This result was also supported by DV-Xa electronic structure calculations. The comparison of the catalytic activities of the spray catalysts and the impregnation catalyst for the NO-CO reactions imply synergy effects between gold nano-particles and alumina support.

Oct 1, 2003

By Erkan Bayrak, Serkan Erkara, Ozkan Duzgun, Ekin Gungor

This paper presents part of the outcomes of the drill and blast optimization project carried out at Kisladag Gold Mine in Turkey. Kisladag Gold Mine is the largest gold mine in Turkey with a low-grade, bulk-tonnage, open pit operation that uses heap leaching for gold recovery. After blasting, the ore is fed to a three-stage crushing circuit which prepares crushed ore approximately -10 mm (0.39 in) for heap leaching. Crusher downtime analysis showed that blocky material and insufficient feed are causing significant downtimes with the primary crusher. This was supported by the fragmentation data collected to date. It was decided to initiate a fragmentation project to understand the variation in the run-of-mine (ROM) size with a view to provide a consistent feed to the crushing circuit. The study includes the analyses of the ore strength and structure, image analysis of the fragmentation pictures acquired from blasts, blast auditing and quality assurance and quality control (QA/QC) analyses. During this project, over 200 fragmentation pictures were acquired from 47 blasts to optimize ore and waste blasts. Ore strength varies between 30 and 120 MPa and rock quality designation (RQD) ranges between 30 and 100. A site-specific fragmentation model was used to calibrate the fragmentation for blast domains formed. In addition, alternative cases were simulated to achieve blasts designs with consistent ROM fragmentation size distribution. Alternative blast designs that include stemming length and powder factor changes were suggested. Long stemming length, drill cuttings use, free faced blasts, small shot sizes and poor stemming length control were some of the key issues causing coarse fragmentation.

Jan 1, 2015

By L. A. Morley

Volume IV of the final report examines the problem of indirect contact of overhead high-voltage power lines by mining personnel. This refers to the contact of energized lines by workers through some intermediate conductor such as a metallic tool or a piece of high-reaching mobile equipment, thus the term "indirect contact." The shock hazard presented by such contact has been a major cause of electrical fatalities associated with mining operations. The report volume is divided into three major areas. The first gives a general background of overhead lines, basic characteristics, and associated hazards, and continues to describe presently used techniques and devices which attempt to alleviate the contact problem. The second area narrows the discussion to the mining industry by presenting a detailed analysis of 39 overhead-line contact accidents in mining since 1970. The third major section uses the information from the first two areas to formulate recommendations to prevent these accidents and subsequent electrocutions at mining operations.

Jan 1, 1982

By Anne Lemnitzer

Full-Scale cyclic field testing was performed on a 3x3 pile group consisting of nine cast-in-drilled-hole (CIDH) reinforced concrete shafts and a comparable single-shaft in order to investigate group interaction effects. Both specimens were constructed with pile diameters of d = 0.61m (2 ft), fixed head boundary conditions, and placed in stiff clayey soil at a test site near the LAX Airport in Southern California. Internal instrumentation was installed in the single pile as well as in three piles within the pile group to obtain pile curvatures. External instrumentation controlled the lateral displacement of the specimens. A combination of experimentally and analytically obtained p-y curves for the single pile was used to simulate results for piles located in the group when field data were not available. All test specimens were tested to structural failure and excavated after test completion to investigate pile damage and plastic hinge formations. Calculated group interaction factors ranged between 1.0 at very small displacement levels of <2.5 mm (0.1 in), 0.8 at the initiation of the pile-soil-pile interaction, i.e. between 4 mm - 15 mm (0.16-0.6 in), and increased towards 0.9 near structural failure (displacement >25 mm or 1 in). A literature set of p-multipliers was found to reproduce an accurate fit to the available load displacement test data from the group.

Jan 1, 2010

GENTLEMEN, lt is with much pleasure I meet you tonight at this the second meeting of the Australasian Institute of Mining Engineers, held in Western Australia, and I sincerely thank you for the honour you have conferred upon me in electing me as your President. I greatly appreciate the distinction, and will endeavour to fulfil the duties of the office to the best of my ability, and hope to prove a worthy successor to those gentlemen who have held the position before me. On behalf of the local members of the Institute, I extend a hearty welcome to the members from the other States of the Commonwealth, who have come so far to attend this meeting, and also to the non-members whom we have invited this evening. We are especially pleased to have Mr. Gregory, our Minister of Mines and Railways, and the Government and School of Mines officials with us; and I take this opportunity to thank the Premier, Mr. Gregory, and the Government officials for the assistance given us, and for doing so much to make the visit of our members from the other States so pleasant and instructive. I have also to thank the Mayor and Councillors of Kalgoorlie for the courtesy and hospitality given to our members, which is much appreciated.I assume you want me to follow the time-honoured custom of giving a Presidential address...

Jan 1, 1909

By J. M. Cardoso, E. F. Quadros, A. Chiarini, F. Fernandes, G. Vilela, J. Ireno, L. C. Agostini

Based on the geological-geometric characterization of the basaltic rock at the site of a factory for chemical products situated in the Southern region of Brasil, and on results of a significant number of packer tests, the principal directions of flow were estimated, taking into consideration the intersection and the orientation of the joints and the amount of contaminant flow measured in each interval. The tests were performed using the multi-packer hydraulic multitest probe of IPT (HMTP) instrumented with an electric conductivity meter. A method of analysis for three-dimensional evaluation of the amount of contaminant flow in the area was proposed for future mitigation of the problem. Basé sur une caractérization géologique-géotechnique de la roche basaltique existant sur un site dune fabrique de produits chimiques située au sud du Brésil et sur les resultants dún nombre significantif déssais du type packer, les directions principales d´écoulement ont été estimées en considerant l´intersection et orientation des joints et la quantité de contaminant mesurée sur chaque intervale d´essais. Ceux-ci ont été realizes en utilisant une sonde multipacker developée au IPT – São Paulo (HMTP) instrumentée avec un mesureur de condictivité électrique. Une méthode d´analyse 3-D pour l´évaluation du transport du contaminant sur ce site a été proposée pour une future mitigation du problème. Auf Grund der geologischen Struktur des Basalts auf dem Gelände einer chemischen Fabrik in Südbrasilien und der Ergebnisse einer ansehnlichen Zahl von Pumpversuchen wurden die Hauptfließrichtungen bestimmt unter Berücksichtigung des Kluftgefüges und der in jedem Intervall gemessenen Menge kontaminierten Wassers. Die Versuche erfolgten mit dem im IPT entwickelten Verfahren (HMTP) mit Mehrfachpackern und elektrischen Leitfähigkeitsgebern. Ein analytisches Verfahren zur dreidimensionalen Ermittlung der Mengen kontaminierten Wassers wurde für die künftige Befassung mit dem Problem entwickelt.

Jan 1, 2003

By C. M. Rule

Energy efficiency is currently a significant area of interest due to the Eskom power situation, which led to severe power impacts to the PGM, and indeed whole SA primary industries, in early 2008. Anglo Platinum has focused on energy efficiency for a number of years, especially in the concentrator operational area. New comminution technologies have been aggressively developed, which have shown real metallurgical efficiency gains as well as significant energy efficiency and saving potential for Anglo Platinum?s total electrical consumption as the company expands into a growing PGM demand market. This paper illustrates this programme?s activities, potential and considerable achievements to date.

Jan 1, 2009

By Nathan T. Lowe

This report updates an accounting of mines and prospects in the Seafoam mining district, Custer County, Idaho, begun during mineral appraisal of the Idaho Primitive Area. Thirty-two mine and prospect locations have been added to the Bureau&apos;s Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of mineral appraisal of the River of No Return Wilderness; most previously known locations were field checked and the updated information added to the data base. The district&apos;s major deposits include polymetallic fissure veins of gold-silver-lead-zinc-copper hosted by granodiorite and quartz monzonite which have been intruded by dikes ranging in composition from rhyolite to dacite, and vein type replacements of silver-lead-zinc-copper hosted by calcareous xenoliths imbedded in major intrusives. These deposits may be related to the intrusion of the Rapid River pluton or the Casto pluton. The dominant northwest structural trend is parallel to an aeromagnetic high, a weak gravity salient, and the Blue Bunch Mountain dike swarm.

Jan 1, 1983