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By H. O. Hofman

INSTITUTE OF TECHNOLOGY, In deternlining experimentally the fusibility of clays, two kinds of methods may be distinguished—the direct and the indirect. Of the direct methods, that of Seger has found

Jan 1, 1899

By Hal T. Morris

The main Tintic mining district in central Utah has produced approximately 13,500,000 tons of ore, containing silver, lead, gold, copper, zinc, and other metals, valued at more than $315,000,000. More than 90 per cent of this ore has come from large, irregular ore bodies that have replaced folded and faulted limestone and dolomite strata. Of lesser importance are replacement veins that chiefly cut contact-pyrometasomatized carbonate rocks and fissure veins that cut altered intrμsive bodies and volcanic rocks. The district is in the west-central part of the East Tintic Mountains, a north-trending fault-block range near the eastern margin of the Great Basin. The consolidated sedimentary rocks exposed at the surface and in mine workings are miogeosynclinal deposits more than 10,000 feet thick that range in age from late Precambrian to Late Mississippian. They are folded and strongly faulted and are partly overlain by volcanic tuffs and agglomerates and by extensive flows of porphyritic and vitrophyric quartz latite, latite, and trachyandesite of Eocene age. All of these rocks are locally concealed beneath thick alluvial deposits of Pliocene and Quaternary age. The Eocene and older rocks are cut by dikes, sills, and small stocks of porphyritic quartz monzonite, monzonite, and latite, which are genetically related to the ore deposits. The district is inactive except for the production of halloysite clay and for minor leasing activity and exploration ventures. Several exploration targets remain untested.

Jan 1, 1968

By C. E. Jordan

The Bureau of Mines has investigated the fundamentals of fatty acid/fuel oil conditioning for improved flotation selectivity. Both conditioning time and intensity can provide optimum flotation selectivity as well as good recovery. Traditional conditioning seeks to optimize conditioning parameters with subsequent recovery of the hydrophobic mineral. In the fatty acid/fuel oil system many silica gangue particles are also rendered hydrophobic by the flotation collector. Fundamental studies have shown that particle-particle collisions transfer the collector reagents selectively to the mineral surfaces with the highest affinity for the reagent. This mechanism deactivates the gangue particles while increasing the collector reagent loading on the selected mineral. The degree of this transformation is directly related to the number of particle-particle collisions which can be controlled through conditioning time or conditioning mixing intensity.

Jan 1, 1995

By Bora Okumusoglu, Devon K. V. Mothersille

"AnchorTest is an innovative software package, specifically developed for tablets, that permits ground anchor test data assessment and management in real time. The solution has two components: a front-end tablet app runs on the Apple iPad platform, and a back-end Cloudbased system running on Amazon Web Services with an online cross-platform website, which can be accessed from any PC, tablet or even mobile smartphone. This tool provides full data analysis and data management capabilities and portability to create greater efficiency in the anchor testing process. AnchorTest is programmed to accommodate the major international anchor testing codes and incorporates an intuitive user interface, which is revolutionary compared to conventional engineering software designs. The use of this tool creates an environment where the testing of ground anchors has effectively become a paperless exercise with greater efficiency and access to instantaneous feedback on the performance of anchors in relation to established acceptance criteria.Historically, project personnel record and analyze the results from anchor load tests using spreadsheets and a laptop computer and/or on predesigned paperbased test sheets (usually as a backup of the testing). In addition, the processing of the test results is not typically performed in real time as the testing progresses — the calculations and analysis are performed either afterward while still on site (if a field office is available) or after returning to the office. Undoubtedly, on larger projects containing numerous anchors where multiple anchor tests may be performed at the same time, processing, analyzing and accepting the load test data and results can be especially time consuming, which could cause delays to the construction schedule.DevelopmentThe need for a more automated and digitized approach to record, process and analyze the data from anchor load tests was highlighted at a deep basement project for a mixed-use development complex in Moscow, Russia. The diaphragm wall supporting the structure was approximately 1,970 ft (600 m) in perimeter length and about 148 ft (45 m) deep, with an excavated depth of about 82 ft (25 m), which required six levels of single bore multiple anchors (SBMAs). This project provided a challenge to recording, processing and signing off on the data generated from some 3,600 3-unit SBMAs. More specifically, for this project, three hydraulically synchronized stressing jacks were used to stress and proof test each 3-unit SBMA, which resulted in nearly 10,800 data plots of the load-extension tests being generated. This project served as the main impetus in the conceptual design and optimization of AnchorTest."

Jan 1, 2017

Mine site rehabilitation is the repair of the disturbance caused by mining on the immediate mining area and also on the surrounding environment. The long-term objectives of rehabilitation can vary from simply returning an area to a safe and stable condition, to restoring the mined land to a state as close as possible to its pre-mining condition, capable of being self-supporting and having a beneficial final land use. This paper investigates the importance and benefits of environmental planning, in particular for rehabilitation, and how input into daily operations can allow mining to progress with limited impact on the surrounding environment. It will also identify some of the key mistakes currently made during mining which could be averted by implementing prior planning and incorporating environmental consideration into daily operations. A number of rehabilitation opportunities will also be detailed for the different stages of the life cycle of a coal mine.

Jan 1, 2007

By D. Harrington

In recent years over 100,000 persons have been killed annually in the United. States by accidents; about one-fifth of these have been workers in some of our industries; about one-third have been killed by motor vehicles; about another third have mot death in home accidents, chiefly falls, burns, scalds, explosions, poisons, asphyxiations, suffocations, cuts, scratches, and so forth; and the rest have been killed in public accidents, excluding those caused by vehicles but including accidents on railroads or electric cars, drowning, and deaths by firearms and. other means. Definite statistics on nonfatal accidents are not readily available, but at least 10,000,000 fairly serious accidents probably occur in the United States annually. The latest industrial-accident statistics are obtainable from 1935 National Safety Council publications, in which annual industrial fatalities are divided about as follows (in round numbers): Agriculture, 4,500; trade and service, 4,500; construction, 3,100; transportation and public utilities, 2,900; manufacturing, 2,600; mining, quarrying, petroleum, etc., 1,900.

Jan 1, 1938

By Bordeaux Sciences Agro-INRA UMR 1065 SAVE, S. Piutti, E. Benizri, S. Lopez

Ultramafic soils display high concentrations of nickel (Ni) and a number of nutrient deficiencies (e.g. N, K, P). Ni-hyperaccumulator plants have evolved on such environments, developed specific metal homeostasis showing concentrations of Ni sometimes above 1% in their aerial biomass (Baker & Brooks 1989). Alyssum murale, a Ni-hyperaccumulator, is commonly found around the Mediterranean but can grow on non-ultramafic soils as well, with an altitudinal extension ranging from sea level to 2000 m.a.s.l. Rhizosphere bacterial communities associated with Ni-hyperaccumulator plants can differ from those of non-accumulating plants growing at the same site. Among edaphic factors that could influence the phylogenetic structure of the bacterial communities, altitude and metal-bioavailability and in particular nickel could be significant. However, most studies have focused on analyzing soils with techniques that provide little detail about the phylogenetic structure of these bacterial communities present in ultramafic soils. The objectives of this study were to understand the specific changes in the structure of A. murale rhizosphere bacterial community that occur across two gradients: 1°) elevation and 2°) Ni geochemistry, using pyrosequencing technique (454-pyrosequencing of 16S rRNA gene). It was found that the higher the soil chemically-available Ni contents, the higher the relative abundance of Proteobacteria and Actinobacteria. On the contrary, the abundance of TM7 decreased with increasing levels of available Ni. Moreover, Chloroflexi was present with 53 to 77% of relative abundance. These results demonstrate that soil chemically-available Ni drives the bacterial community diversity in the rhizosphere of Alyssum murale regardless the elevation gradient and other different soil physicochemical parameters. These results should now be confirmed in different ultramafic edaphic environments worldwide (e.g. ultramafic lateritic covers) and in the rhizosphere of different hyperaccumulator taxa.

Jan 1, 2016

By T. J. Fenner

Research conducted in South African mines has demonstrated the benefit of ground penetrating radar for the detection of geologic features and hazards. This is crucial for safety and production considerations in underground mines that are as much as 4 kilometers deep. This paper describes a new ground penetrating radar system designed specifically for high quality data acquisition, in the harsh conditions of deep underground environments, for use by operators with minimal geophysical experience. Design criteria included automated functions, intrinsic safety, light weight and minimal power requirements. Data is processed on the ground surface by geoscientists using a PC.

Jan 1, 1994

By Weihua Song, Hongwei Zhang, Feng Zhu, Sheng Li, Guoshui Tang

"Rock burst is one of the most serious dynamic disasters in coal mining. Rock burst prevention involves two difficult tasks: systematically evaluating the occurrence conditions and effectively forecast for rock burst. This paper systematically studies the effects of natural geological dynamic conditions and mining engineering on and forecast for rock burst. It establishes the evaluation method and index system of rock burst geological dynamic conditions and proposes a method of forecasting rock bursts by monitoring fault activity with anchor cables. Natural geological dynamic conditions are a necessary condition while mining engineering is a sufficient condition for the occurrence of rock bursts. Rock bursts in mine must have suitable geological dynamic conditions, and mining engineering activity is merely an inducing factor. There is a good correlation between anchor cable stress variation and fault activity, when the anchor cable dynamometer indicates that the fault is active. It can forecast a rock burst a few days in advance. This technique has been successfully applied to Panel 83003 of a coal mine in China, which improved the safety production level of the mine and found a new way of rock burst evaluation and prediction.INTRODUCTIONRock burst is one of the most serious dynamic disasters in coal mining. With the increase of mining depth, rock burst disaster is becoming more and more serious. Systematically evaluation and effective forecasting of the occurrence of rock burst in the coal mines are important and difficult work in the control of rock bursts. Chinese researchers have performed numerous researches on rock bursts, Qi et al., established the rock burst model of frictional sliding instability, explained the occurrence mechanism of rock bursts by stick-slip phenomenon in frictional sliding, gave full consideration to the influence of primary rock stress and mining-induced stress on rock burst occurrence, and proposed the stress controlling theory of rock burst. Pan et al., [3] put forward the criterion of perturbation response, explained and analyzed the problem of rock burst in circular openings, put forward the ratio of coal-rock elastic modulus and reduced modulus is the significant parameters for the determination of stabilization; systematically summarized the rock burst distribution, type, mechanism and control in China. They classified rock bursts into three types: coal compression, roof fracture and fault movement. By applying energy transfer principle and conservation of energy, combined with the analysis of the weakening of rock fabric damage, Zhou and Jiang put forward the theory and equation for the occurrence of coal-rock mass impact effect. They analyzed and discussed the formation mechanism of rock burst by combining impact effect theory and energy equation. Wang et al., recognized that the mechanism of rock burst which induced by fault, fold and phase transition is the superposition of tectonic stress and mining stress and that the axes of syncline and anticline and their flanks are the location where rock bursts mostly occur. To prevent stress superposition is the efficient way to control the structural rock burst [7]. Jiang et al., summarized the research achievement of rock burst mechanism and controlling techniques and existing problems in recent years in China, and pointed out the direction to improve the level of prevention of controlling rock bursts in coal mines."

Jan 1, 2015

By Henry J. Jacoby

This report concerns Contract No. 3B of the Port Richmond Project, for the Department of Water Resources of the City of New York. It involves the construction of 7, 000 ft. of 7 ft. finish I. D. interceptor sewer by tunneling in soft ground, as well as associated manholes, regulator chambers, siphons and miscellaneous sewers and structures, beneath a heavily travelled perimeter road in Staten Island. The Contractor is Richmond Constructors, a joint venture of Grow Tunneling Corp., sponsor, MacLean Grove & Company, Incorporated, Morrison-Knudsen Company, Inc., and Andrew Catapano Co., Inc. Project manager is Paul DeMarco, Vice-President of Grow Tunneling Corp. The cortract, as designed and bid, requires the use of liner plates 101 -0" O. D., and both cast iron and steel designs of several widths were included in the bid documents by the owner. The specifications also required the contractor to install and put into operating condition, prior to commencement of mining, a complete low pressure compressed air plant and all accessories for mining in compressed air, even though the contractor was given the option of using other methods of ground water control. A third requirement of the specifications was that a shield be used, either manual or mechanical, and with full provision for "breasting". BACKGROUND The first soft ground shield driven tunnel in the United States was in New York City and was built under Broadway in lower Manhattan in 1869

Jan 1, 1974

By L. M. Chan, D. H. Carlson, J. H. Johnson

"This paper discusses the evaluation and application of a portable parked-vehicle tailpipe emissions measurement apparatus (EMA). The EMA consists of an exhaust dilution system and a portable instrument package. The EMA instantaneously dilutes and cools a sample of exhaust with compressed nitrogen or air at a known dilution ratio, thereby presenting it to instruments as it is presented to personnel in the surrounding environment. The operating principles and governing equations of the EMA are presented.A computational method is presented to determine the engine operating and performance parameters from the exhaust CO2 concentrations along with an assumed engine overall volumetric efficiency and brake specific fuel consumption. The parameters determined are fuel / air ratio, mass flow rates of fuel, air and exhaust emissions, and engine brake torque and horsepower. These calculated engine parameters are used to characterize engine load when performing EMA in-field tailpipe sampling without a dynamometer, and to detect deteriorated engines.Evaluations of the EMA by comparison of diesel tailpipe measurements with those made using laboratory-grade instruments showed that the EMA measurements are accurate and reproducible. The results also show that the EMA is capable of detecting emission concentration changes resulting from engine faults. Calculated engine operating and performance parameters correlate and compare well with laboratory-measured values.The EMA in-field engine loading and tailpipe sampling procedures for parked vehicles are presented, and results of the EMA field measurements are also presented. Low coefficients of variation for repeat EMA tailpipe measurements on diesel-powered haulage vehicles in four underground mines indicate that the EMA in-field engine loading and tailpipe sampling procedures are reproducible.An analysis of EMA tailpipe measurements for three haulage vehicles in one mine shows that the EMA can: 1) identify haulage vehicles that emit excessively high pollutant concentrations, and 2) provide data needed to evaluate and determine the efficiency and effectiveness of tailpipe emission control devices.Finally, recommendations for a proposed commercial EMA system are presented. This commercial system would overcome many of the adverse features of the prototype EMA used in these tests."

Mar 1, 1992

By Nehad Elsafty

It is always necessary to expand existing buildings, so that they could meet the growing societal needs. Compared with demolishing them and then constructing new ones, the expansion of existing buildings could not only reduce project cost, but also save the use of energy and raw materials in projects. Therefore, it is widely adopted in most under-developed countries. However, the expansion of existing buildings is not an easy task. It has been involved with a lot of issues in defining the scope of work, planning landscape, managing construction activities, etc. This paper investigates the potential challenges in expanding existing buildings. The project of expanding the Al-Agoza Hospital, one of the biggest and oldest hospitals in Cairo, Egypt, is selected as a case study. In the case study, the project documents have been carefully reviewed. The project engineers and the health-care professionals working in the hospital have been interviewed. This way, the point of views from the owner, the architect/engineer, and the contractor have been taken into account. Several lessons are learned through the discussion with these people. The results from this paper are expected to provide pieces of useful advice and suggestion for the expansion of existing buildings in the future.

Aug 1, 2013

By Irving Hartmann

Falls of roof in coal mines and means of preventing them have been subjects of study for many years, and an extensive literature has resulted. Usually each individual paper has placed emphasis on one phase of the subject, such as fatalities, nature and extent of nonfatal injuries, methods of tembering (particularly in rooms or other wide places), safety along retreating rib lines, and methods of causing falls in abandoned areas. It is only in recent years that there has been persistent question as to why

Jan 1, 1941

By Ruddle R. W.

An outline account is given of the smelting of copper and the chemistry of the process. A table provides compositions of the more important minerals from which copper is won by smelting. Roasting is discussed as is smelting using reverberatory furnaces, blast furnaces and flash smelting. A brief discussion of converting covers the upright (Great Falls) converter and the horizontal (Peirce-Smith) converter.

Jan 1, 1953

By B. K. Shibler, W. G. Sandell, G. M. Potter, H. D. Snedden

"INTRODUCTION During the course of the investigation of the occurrence of manganese deposits in the western United States, examining 'engineers of the Bureau of Mines collected samples from seven manganese properties in Grand and beery Counties, Utah. These were supplemented by five samples submitted by property owners. Since all of the ores were too low-grade for use in producing ferromanganese for steel manufacture, some means of beneficiation was required to produce marketable concentrates, and metallurgical studies were made on each of the samples.Most of the ores Investigated are similar in one respect: At least part of the 'manganese oxide areas contains minute inclusions of gangue. This occurrence materially enhances the complexity of the ore, partly by .increasing the complexity of mineral association, but largely through making manganese-quartz liberation more difficult. In such ores, there is a marked tendency for the manganese minerals to be retained as shells or coatings on the surfaces of quartz particles when crushed. Particles of this type represent considerable loss of manganese in tailing, if gravity-concentration methods are employed, or tend to' float, thus carrying an appreciable quantity of gangue into the concentrate, if treated by flotation.Plus 48-percent manganese sinters were made from some of the ores tested, but, in general, intimate association of manganese minerals with silica limited the degree of beneficiation attainable."

Dec 1, 1947

By Harry Vivian

This paper deals principally with the retreating method of mining as applied in the Calumet & Hecla Consolidated Copper Co.'s deep Conglomerate mine, pointing cut some of the difficulties encountered in deep mining and describing the particular methods used at Calumet to carry on a large-scale operation at great depth with a minimum hazard factor. The circular is one of a series dealing with mining methods and costs which is being prepared for and published by the United States Bureau of Mines. ACKNOWLEDGMENTS Acknowledgment is due to those officials and operating heads of the Calumet & Hecla Cc. whose years of familiarity with the conditions developing at the Conglomerate mine as great depth was attained have enabled them to contribute valuable information to the subject of deep-mining problems.

Jan 1, 1931

By E. Demedde

Carbon anodes in aluminium reduction cells are continuously consumed during electrolysis. In prebake cells the anodes are replaced at regular intervals. The spent anodes, called butts, are often allowed to cool in air while emitting fluorides into the building from the hot alumina cover and the adhering bath. In modem smelters spent anodes are placed inside enclosures and fluoride emissions during cooling are effectively reduced. Fluoride emissions from spent anodes were estimated by considering the kinetics of fluoride formation, a heat transfer analysis of the cooling anode butt and the ventilation flow from a cavity. Fluoride emissions from large anode butts cooling inside enclosures were compared with those cooling in air. Good agreement with published experimental values was obtained for enclosures having different leakage opemngs, when a hydrofluorination reaction of the spent anodes was included.

Jan 1, 2006

By Andrew Fletcher

AS good health is the most important asset in life, the development of healthful conditions should be the one common meeting ground of agreement between management and labor. Health should not be a subject to be pulled apart, shoved around, or bargained about. Differences of opinion may exist in the procedure and techniques employed in approaching the goal of maintaining the health of workmen, and in the method of increasing the ultimate profit of the employer by improved working and living conditions. Such matters are doubtless appropriate subjects for discussions between the interested parties, but techniques are only tools. If an employer fails to remedy a hazard or a menace which contributes to poor working condlions, this constitutes a legitimate grievance. It should not be necessary, however, nor is it desirable that fundamentals of health maintenance become matters of collective bargaining, any more than should the principles of management and engineering. I have been especially concerned during the last few months with the propaganda in collective bargaining negotiations throughout the country for including in union contracts a given number of days of sick leave with pay. We all

Jan 1, 1946

By M. R. Geer, H. F. Yancey

0. R. LYONS*—I know that we are all interested in hearing about problems that other people have. To most of the people from the eastern part of the United States, this kind of coal preparation is completely different. It represents washing difficulties that most operators have never experienced, or, if they have, they have refused to consider them because there are coals that are much easier to wash and, therefore. they leave the more difficult ones alone for the time being. E. R. McMILLAN†—I think the au-thors have summarized the material very well. Dr. Yancey has spent a great many years in the study of washing coals, as has Mr. Geer. I might comment briefly on some of the plants that were mentioned, plants with which I have had some con-nection, particularly those of our own company, the Northwestern Improve-ment Co. I would like to point out this: that ill each case, a great deal of work was done in the way of preliminary studies of washability of the coal before plants were built. The first plant of any size built in Roslyn field was mentioned in the paper. This central cleaning plant was designed and built to handle coal from three different mines. I might say that prior to 1935, the year in which the plant was built, the coal was used largely as railway fuel, close to a million tons annually. But as mining increased in depth, it became increasingly difficult to separate and gob much of the impurities underground, with the result that the run-of-mine coal became so high in ash that the railroad eventually was forced to consider installing some kind of preparation plant at the mine. We spent about a year in preliminary studies in cooperation with the Bureau of Mines to find out the best type of plant that would clean the coal. The result, as Mr. Geer has explained to you, is a rather complicated plant, but it is doing a very satisfactory job. We have, however, made a number of changes and improve-n~euts since it was first built. The last addition was the, installation of a cen- trifugal drier to dewater the minus ¼ in. size. We are now contemplating installing heat driers for further drying of minus ¼ in. We use Vissac heat driers for drying the stoker coal, the ¾ to in. The demand for drier coal, for both railway and industrial use, is forcing us to further drying of the coal. The plant that was mentioned as having been built in Pierce County, during the war, was a government sponsored plant. I happen to have had some connection with its design, construction and initial operation. We did what we thought then, and still think, was a very thorough job of preliminary studies in cooperation with the Burea of Mines of the coal from that field. The plant was as good a plant as could be built with the equipment available at that time, 1943. The plant that was mentioned as having been built at Ravensdale for treating the McKay coal was rebuilt about two years ago, and in addition to the modified Elmore jig washer that was mentioned. we added a coucentrating table for re-cleaning the minus 3/32 in. Our object there was to produce a commercial

Jan 1, 1950

By E. G. King

Thermodynamic data for the hydrated varieties of alumina are sparse, and those for the common clay minerals are virtually nil. This paper partly fills the vacuum by reporting low-temperature heat-capacity measurements and entropy evaluations of diaspore (A10(OH)) and three clay minerals of the composition A12Si207?2H20 - kaolinite, dickite, and halloysite. The heat-capacity measurements were made in the temperature range 510 to 298.15° K., and the entropies were evaluated at 298.15° K. Diaspore has an unusually low heat capacity and entropy compared with boehmite (another mineral of the same chemical composition). The entropies of the three clay minerals differ too little for entropy to be the important factor relating to differences in the thermal stability of these substances.

Jan 1, 1961