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By Todd Clarke, Ralf Winterberg

For more than a decade the tunneling industry has explored the potential and benefits of macro synthetic fiber (MSF) reinforced concrete solutions for precast tunnel segments. Parallel to industry investigations, academic research is being undertaken to better understand this material when subjected to the typical loads expected during mechanized tunneling. This paper investigates the performance of MSF reinforced precast concrete tunnel segments by means of an experimental program comprising testing of full-scale tunnel segments. The presentation of the satisfactory results of the experimental testing regime will be complemented by a brief case history from a successfully executed project—an America’s First.

Jun 13, 2021

By Santosh Kumar Ray, DEBASHISH MISHRA, Niroj Kumar Mohalik, SOMU MANDAL, Jai Krishna Pandey, Asfar Mobin Khan

Coal is a low-cost and high-calorific-value fuel. The coal mining industry worldwide has been suffering from severe accidents due to coal dust explosion hazards since its inception. Statistically, it was observed that 12,489 fatalities had occurred in 104 reported mining accidents from coal dust explosions during 1900–2020. There are numerous methods for detection, prevention, and control of coal dust explosions in mines. The underground mining environment is unpredictable and has an array of variables. These undulating factors make it difficult to prevent or control the coal dust explosion hazard. However, coal mining is done aggressively throughout the world, especially in developing countries as coal is a major source of thermal energy used in power plants contributing to about 38% (IEA, (2019), World Energy Outlook, IEA, Paris https:// www. iea. org/ repor ts/ world- energy- outlo ok- 2019.) of world electricity. Worldwide, coal dust explosibility studies are carried out in experimental mines, laboratories, and simulations. The complexity, lack of proper infrastructure, and unavailability of laboratory equipment sometimes make it difficult to study coal dust explosibility. The authors have discussed in detail and proposed that the CFD modelling can be a viable option for studying and evaluating coal dust explosibility.

Jun 29, 2022

By H. M. Thorne

The Petroleum Experiment Station of the Bureau of Mines at Laramie, Wyo., in cooperation with the University of Wyoming, has in progress chemical and refining studies of Wyoming black oils. In general, these crude oils are characterized by their high sulphur, high asphalt, and low gasoline content and are called black oils because of these properties and their color. Characteristics of the various Wyoming black crude oils, as determined by the Bureau of Mines Hempel method of analysis, have been pubished.4/

Jan 1, 1938

By H. M. Thorne

The Petroleum Experiment Station of the Bureau of Mines at Laramie, Wyo., in cooperation with the University of Wyoming, has in progress chemical and refining studies of Wyoming black oils. In general, these crude oils are characterized by their high sulphur, high asphalt, and low gasoline content and are called black oils because of these properties and their color. Characteristics of the various Wyoming black crude oils, as determined by the Bureau of Mines Hempel method of analysis, have been published.4/

Jan 1, 1938

By E. Siami-Irdemoosa, S. R. Dindarloo

"Pareto analysis was used to investigate the failures database of a Hitachi EX1900 hydraulic shovel over one year of continuous operation. The hydraulic system and hydraulic links, hoses and piping were identified as the most critical system and subsystem, respectively. A three-parameter gamma distribution function was identified as the best fit for a probabilistic modeling of the time between failures (TBFs). This distribution was used in a Monte Carlo reliability analysis of the hydraulic system. Autoregressive integrated moving average (ARIMA), within the context of a time series analysis of the TBFs, was proposed as a viable alternative to the traditional technique of distribution fitting. The mean absolute percentage error (MAPE) metric was used to compare the two models. The MAPE value that resulted from the ARIMA was 66 percent smaller than that from the traditional technique in predicting the TBFs.Resumen ¦ Se usó análisis Pareto para investigar la base de datos de fallas de una pala hidráulica Hitachi EX1900 durante un periodo de un año de operación continua. Se identificó al sistema hidráulico y a los enlaces hidráulicos, mangueras y tuberías como el sistema y subsistema más importantes, respectivamente. Se identificó una función de distribución de tres parámetros gamma como el más apto para un modelado de probabilidades del tiempo transcurrido entre las fallas (Tabes por sus siglas en inglés). Esta distribución fue usada en un análisis de confiabilidad Monte Carlo para un sistema hidráulico. El promedio de movimiento integrado auto-regresivo (ARIMA por sus siglas en inglés), dentro del contexto de análisis de serie temporal de los TBFs, fue propuesto como una alternativa viable a la tradicional técnica de ajuste de distribución. Se usó el porcentaje de la media absoluta de error (MAPE) para comparar los dos modelos. El valor MAPE que resultó de la ARIMA fue 66 por ciento menor que el resultado obtenido con la técnica tradicional de predicción de TBFs."

Jan 1, 2015

Profiled on these pages are the eight RMCMI 1994-95 Scholarship Award Winners. Six of the eight winners were present as guests of the Institute at the June convention in Crested Butte, Colorado. Each received recognition at the Institute Awards Luncheon Monday. June 26, 1995. Each state vice president served as the host for the collegiate winner. The first and last winners - Arizona and Wyoming - were absent. Besides receiving a plaque from the Scholarship Chairman, Alan Czarnowsky, each winner receives $750 tuition credit for the coming academic year, as well as transportation, hotel lodging and meals at convention as guests of the Institute. This latter portion is paid by each state vice president. Because this is a continuing award, the winners from the previous year also receive a second $750 for tuition credit in their senior year. A resident from each of the eight RMCMI member states is selected from among Board approved institutions. Criteria for these awards to be made in the spring annually is that the recipient (1) Is a full time sophomore student who will use the tuition credit during the junior year. (2) Be both a U.S. citizen and a resident of the member state. (3) Maintain good academic standing, be pursuing a degree in a mining related field and have an expressed interest in Western coal as a possible career path. The scholarship program includes curricula other than in the mining departments, but in engineering disciplines, such as geology, mineral processing and metallurgy. Contributions to this worthy project are tax deductible to each individual RMCMI member or his firm. Through annual donations of $100 or more, the Patrons of the Institute fund the scholarship program. A listing of current donors is found elsewhere in this book. Donations to this worthwhile program are payable to RMCMI Scholarship and may be mailed to the RMCMI Office. 3000 Youngfield Street, Suite 324, Lakewood, Colorado 80215. Profiles of the 1995 Scholarship Winners follow. [ ] ARIZONA WINNER Brad Carroll University of Arizona - Tucson, Arizona Brad Carroll's hometown is Tucson, Arizona but his summer work is in Oriskany Falls, New York where he is a quality control technician, truck driver and equipment operator for the Eastern Rock Products. Brad served as vice president and treasurer for the SMWAIME student chapter at the University of Arizona for the past three years He was assistant and mine foreman at the San Xavier Mining Laboratory near Tucson. Upon graduation Brad plans to find a job in a southwest mine. He is a totally self supporting student. [ ] COLORADO WINNER Zane Znamenacek Colorado School of Mines - Golden, Colorado Zane Znamenacek hails from a small town in Colorado - Alamosa - where he 4 was a 4.3 GPA in high school. As a student at Colorado School of Mines, he has many hobbies to ease the tension of education. Foremost among these is skiing, mountain biking, billiards and spring rugby. He hopes to further mining technologies and contribute to the industry by working in it full time. In 1997 he will pursue whatever opportunities are available to graduating mining engineers

Jan 1, 1995

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds of Clay, Gilmer, and Lewis Counties, W. Va. In 1966, almost 1.3 million tons of coal was mined in these counties, of which more than one-half was from the Pittsburgh coalbed. Washability analyses were made of 16 coalbed samples. Of these, only 11 samples could be upgraded to metallurgical quality. For steam or power generation five of the coals were of low sulfur content as received. The remaining samples were generally of medium sulfur content even after upgrading.

Jan 1, 1969

By M. R. Haibach, M. L. Shema, J. M. Silvis

"Since 2005, longwall coal mine operators in Pennsylvania (US) have been required to collect extensive hydrologic and biological data to document pre- and post-mining conditions of aquatic resources (streams and wetlands) overlying the subsidence control plan areas. Continued operation of the longwall mine is dependent upon empirical data demonstrating that the undermined aquatic resources have either been maintained or restored to an accepted range of pre-mining conditions. This study used quantitative hydrologic methods and comparative biological metrics to examine response of aquatic resources to longwall subsidence at the Bailey Mine located in Greene County, Pennsylvania. This study analyzed data from over 25 miles of streams and over 8 acres of wetlands that traverse the 4,779-acre study area. Hydrologic analysis of flow intermittency suggested that there are variable degrees of change to headwater streams immediately following mining; however, the majority of the effects are reversible through streamflow mitigation measures. Furthermore, the post-mining discharge from streams can be restored to within the range of pre-mining conditions the majority of the time. Biological assessments showed that greater than 95% of assessed stream length has maintained its ability to support benthic macroinvertebrate communities following mining and intervention (i.e., mitigation). Comparative metrics of the benthic macroinvertebrate communities showed that the biological community in 48 of the 50 sample sites is being maintained or restored across both high- and low-gradient streams. The effectiveness of intervention was further substantiated by the similarity in recovery times between streams having no intervention (median = 2.1 years, 95th percentile = 4.9 years) and streams with intervention, when recovery times were measured from the date of the intervention (median = 1.7 years, 95th percentile = 4.7 years). Changes to individual wetlands were observed between the pre- and post-mining assessments, but cumulatively a net gain of 7% in wetland acreage was realized. Hydrologic assessments were used to infer whether there was a potential that streams had been affected by mining; however, the ultimate test of stream recovery is based on biological metrics that establish the relative quality of the biological communities following mining. Overall, the hydrologic balance is being protected and the aquatic life use of streams is being maintained within the Bailey Mine’s subsidence control plan areas."

Jan 1, 2017

By M. G. Corson

INFORMATION regarding the use of manganese alloys has hitherto been incomplete and available only from widely scattered sources. This paper attempts a systematic description of properties and uses of alloys other than manganese bronze, manganin and duralumin, which are probably the only non-ferrous alloys associated with manganese in the minds of most metallurgists.1 PROPERTIES OF MANGANESE Manganese can react either acid or basic; it is hard to obtain in the pure state; it has two different crystalline lattice structures, both of the cubic system, one stable above 850° C. and the other below 650° C., both coexisting in the intermediate range. Although the commercial product is hard and brittle, the pure metal seems to be ductile. In fact Zhemchuzhny, in Russia, was able to obtain ductile manganese and draw it to fine wires by the simple expedient of adding about 3 per cent. copper to the alumino-thermic product. Copper most probably brings the sili-cides, aluminides, nitrides and carbides present in the commercial product into a much less harmful form of distribution. One industrial use that can be foreseen for wrought manganese articles is as anodes for electrolytic processes in sulfate and nitrate solutions, particularly with high voltages. A practically insoluble skin of manganese peroxide is likely to form in such cases and an insoluble and strong anode material will be available.

Jan 5, 1927

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1955 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 116 samples of aviation gasoline and for 38 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' 1955 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 20 manufacturers of aviation gasolines and of 16 producers of aviation jet fuels are represented.

Jan 1, 1956

By Dave Deglon, Andrévan der Westhuizen

Objectives ?Survey typical Met Accounting streams at the Zincor refinery ?Determine Precision in Metal Conc?s Measurements for Monthly Met Balance ?Determine the Components of Variance in these Met Acc Values (Sampling, Preparation, Analyses) ??Common plant practice? should be mirrored even though not always in perfect agreement with ?laid down procedures? or ?good practice? ?Mass Measurement and Inventory Measurement was considered in less detail ?not reported here

Jan 1, 2005

By Jack O. Jones

The Furnish mine, Caharrus County, W. C., was operated intermittently until 1905 as a gold mine. Scheelite was discovered by A. L. Mash in the mine dumps of the Furniss and Phoenix mines, and he later informed the Bureau of Mines of his discovery. The Bureau of Mines, in two projects at the deposit in 1948 and in drilled 12 holes totaling 1,706.6 feet, examined and sampled the underground workings, excavated by bulldozer and hand, 3,155 linear feet of trenches and collected numerous samples for assay. The best scheelite shown; was found in the underground exposure of the Furniss mine.

Jan 1, 1950

By R. L. Cosgriff

A commercial, battery-powered mine vehicle has been equipped for remote operation in coal mines. This vehicle is controlled by an operator from the remote station. Command signals originating at the remote station as well as video and data signals originating on board the vehicle are relayed between the remote station and vehicle using a single coaxial line. This coaxial line is normally 2,000 feet in length and is reeled in and out from a drum mounted aboard the vehicle The vehicle has a maximum speed of 6 ft/sec and a minimum speed of 4 ft/sec using 36-volt excitation of the traction motor. If this traction motor is excited by two of the three batteries, 24-volt excitation, the vehicle will travel at approximately 2 ft/sec. The speed can be reduced by the operator to 1 ft/sec. This vehicular system has been tested in coal mines. Presently, the major limitation of this system is associated with fatigue failure of the splices in the coaxial line and lack of mobility caused by its 3-wheel design.

Jan 1, 1974

By Haldane J. S.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) It was shown in the last Supplement to the Registrar-General's Reports, in connection with the census of 1901, that the general death-rate among colliers was considerably lower than in the great majority of occupations but that there is an exception to this in the case of colliers above the age of 55. Examination of the statistics finds that the excessive death-rate among old colliers is to a large extent only apparent, and that the real excess of bronchitis from which they have suffered has greatly diminished. It is concluded: (1) that good ventilation is of considerable importance to the health and continued working efficiency of miners, as well as to their safety from accidents; and (2) that there is no real statistical evidence of harm resulting from the inhalation of coal-dust or shale-dust in the quantities ordinarily breathed by miners, and a strong presumption that the dust they breathe protects them against serious dangers from bacilli that are removed from the lungs by the dust-clearing cell mechanisms

Dec 1, 1916

By A. Broussaud

An original methodology has been developed for steady state simulation of selective grinding and mineral liberation in rod and ball mills. Three fundamental aspects of the methodology are presented successively : modeling ore texture, modeling grinding and its selectivity, and modeling mineral liberation. The methodology for modeling ore texture includes the conversion of 2D data into 3D reconstructed information and the use of the BILCO coherent material balance software. The models for grinding Simulation are classified into three levels, corresponding to three levels of available experimental data. All models account for grinding selectivity and for variations of engineering para-meters and operating conditions. An algorithm has been introduced to forecast mineral liberation, compatible with accurate simulation of selective grinding, which generates reasonable results.

Jan 1, 1987

By Robert D. Thomson

The Bureau of Mines has compiled coal reserve data for the United States as of January I, 1974, for bituminous and anthracite coalbeds 28 inches or more in thickness to a maximum depth of 1,000 feet and for Lignite beds 40 inches thick or greater. These data were organized by State, county, coalbed, and rank. To evaluate the reserve by sulfur content, the reserve and analytical data from the Bureau of Mines energy data bank were synthesized using computer techniques. The reserve base in the Eastern States was determined to be 202.3 billion tons. Bituminous coal accounts for the greatest reserve base: 161.5 billion tons of deep-minable coal, and 32.5 billion tons of strip-minable coal. Virtually all of the anthracite reserve base, 7.3 billion tons, is minable by underground methods. All of the lignite, 1 billion tons, is strip minable. Subbituminous coal is not significant in the Eastern United States, About 14 percent of the bituminous coal reserve base, 26.5 billion tons, contains 1.0 percent or less sulfur. About 87 percent of the anthracite reserve base, 6.3 billion tons, is low-sulfur coal.

Jan 1, 1975

By Marc Arl

Failures of the face and roof above longwall shields have caused days and sometimes weeks of lost production. A common recovery method for these failures has been to pump light weight cementitious grout into the roof and face cavity to stabilize the area This approach while effective is very time consuming and costly. Mines in several coal producing nations have over the past few years been applying phenolic foam grouts in these situations in lieu of cementitious materials. Phenolic foam is a two-component injection product intended for cavity filling, air and gas sealing and the consolidation of highly fractured strata. The properties of phenolic foam; rapid application, quick setting, high expansion rate, high compressive strength and excellent anti-static properties, produce a fast, safe and cost effective cavity filing solution. The product is also classified as fire resistant and so is also suitable for sealing off underground heatings and for aiding fire fighting operations in deep mines. This paper will discuss the application and use of phenolic foam in various underground coal mines in the world over the past few years.

Jan 1, 2005

By PEILIN LAN, LEONARD HILL, SIMON TIMBILLAH, BERNARD FOSU, CESAR SOSA-BLANCO

The use of sodium hydrosulfide (NaHS) in most of the operations in by-product molybdenum flotation comes with safety concerns and, in some instances, a high reagent cost. Engineered solutions at the various operations where NaHS is used have reduced the possibility ofH2S gas evolution immensely. However, the threat of exposure remains, and this, coupled with the high dosages of NaHS consumed, supports the continued search for alternative depressants. This paper focuses on efforts to study the applicability of disodium carboxymethyl trithiocarbonate (DCMT), an organic depressant, as an alternative to NaHS. Benchscale rougher flotation results for samples from the Sierrita Cu–Mo plant showed the best DCMTperformance at 8 kg/t of DCMT and pH=10.5 with 30 min of shear conditioning and 10 min of flotation conditioning time. The Aminpro plant model simulation confirmed that DCMT with 4–8 kg/t under certain shearing and conditioning times achieved superior or equivalent Mo–Cu separation efficiencies when compared to NaHS.

Apr 19, 2021

By Stephen Krickovic

THERE is today no proven continuous mining machine that can be used under all the varying conditions found in most bituminous coal mines. During the last five years, however, both the machines and methods of using them have been improved. Coal operators can now exercise a fair degree of selectivity, except those who must struggle with thick and hard partings and operate in seams less than 40 in. thick. It must be realized, then, that more than one type of continuous miner may be used advantageously in the same coal mine. Although this appears to violate the standardization generally sought after, the gain can more than offset added maintenance and, to a lesser degree, operating problems.

Jan 12, 1957

[RESULTS OF THE PRIMARY CONVENTIONAL PERFORMANCE AND COST MODEL OF THE UNIT OPERATIONS OF UNDERGROUND PERCUSSIVE DRILLING AND BLASTING]

Jan 1, 1977