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By Arne Landsberg

The Bureau of Mines measured the vapor pressure of FeC12 , FeBr2, FeI2, Sb, Bi, Cd, Mg, Pb, FeC13 , and VCl2 using the Knudsen-and torsion-effusion methods, and on FeC13 -NaC1 mixtures, Au2Cl6, and MgNi2 using only the Knudsen method. Apparent vapor pressures calculated from the experimental data vary with orifice size and method of determination. Reaction with residual oxygen in the instruments was noted to have an effect on the iron halide data. Vapor pressure curves plotted as log P versus 1/T (where P is pressure and T is absolute temperature) for one substance using several orifice sizes tended to converge at a single point when extrapolated beyond the experimental region. All of the data, except those of VC12, agree with previously published results. The importance of comparing effusion measurements with those obtained by other methods and the variations encountered with various orifice sizes are discussed.

Jan 1, 1977

By Joanne G. Petrini

ISO 26000 Unique Process Unique Personality ?Almost 10 years in the making ?What type of standard is this? Different type of ISO Standard ISO 26000 Structure and Substance ?Principles ?Core Subjects ?Implementation Guidance ISO 26000 Impact ?Same old, same old? ?So Is there really anything NEW? ?Should I care??

May 1, 2011

The NIOSH Office of Mine Safety and Health has released communication products about flyrock safety in the form of informational brochures, flashcards, and toolbox talk materials. Both the mining and construction industries are targeted with these helpful communication tools. These new products can be used as refresher training for employees and as introductory safety materials for onsite visitors.

Dec 1, 2006

By Jerry B. F. Champlin

NIOSHAn accelerated testing procedure developed by the Bureau of Mines for evaluating commercially available corrosion inhibitors is described. Ultra-sonic agitation of the corrodent solutions and the hot-finished mild steel test coupons was used to evaluate the effects of several variables on the effectiveness of two corrosion inhibitors. Small changes in the weight of the test coupons in both controlled and inhibited corrodents, before and after exposure, affected the precision and accuracy of the results. Minute amounts of oxygen in the systems were found to be causing the relatively large deviations in the corrosion developed in the controlled tests. Microscopic examination of the test coupons revealed that both surface preparation and internal strains resulting from fabrication methods materially affect corrosion behavior.

Jan 1, 1965

By Reda Mikhail, M. Birkan Bayrak

The Washington State Department of Transportation (WSDOT) State Route (SR) 167/70th Avenue East Vicinity Bridge Replacement Design-Build project is located in Fife, Washington. This $40 million project consists of replacing the existing 70th Avenue Bridge over Interstate 5 (I-5) with a single-span bridge of about 220 feet long with approach embankments. The subsurface conditions along the new bridge alignment generally consists of alluvial deposits with high potential of liquefaction overlying glacially overridden deposits. In the early stages of the project, drilled shafts were considered as the deep foundation system; however, after an additional subsurface investigation is completed at the site, driven pipe piles were selected as the deep foundation system. Bridge abutments are supported by 24-inch diameter, 80-foot-long open-end driven steel pipe piles. The pile length was determined to bypass a relatively thick liquefiable zone and to tip the piles above what could be compressible soils. The use of advanced seismic analysis was instrumental in optimizing the pile length. The dynamic testing performed on numerous piles indicated what could be unique soil setup factors compared to those measured in local projects as well as those reported in national design manuals. Detailed discussions of the pile foundations design and construction is presented in this paper.

Sep 8, 2021

By M. B. McClenaghan, O. P. Lavin, Ian Nichol

"Abstract-Exploration in most areas of Canada has to contend with problems posed by glacial overburden. In many areas exploration for gold has been based on the sampling of tills, frequently by deep overburden drilling, and analyses of heavy mineral concentrates. Notwithstanding the significant role that till geochemistry has played in the discovery of some important gold deposits over the last few years, increased appreciation of the nature of the glacial history and stratigraphy and the character of gold within till has led to the recognition of a number of ways whereby the effectiveness of exploration can be improved upon.In order for till geochemistry to be useful in exploration, a number of conditions must be fulfilled, including:1. mineralization, or alteration halo related to mineralization, subcropping at the bedrock /over­ burden interface; 2.glacial erosion and dispersal of a recognizable signature of mineralization into the glacialsediments; 3, preservation of glacial sediments containing this geochemical component (trace metal or mineral) at positions subsequently selected for sampling (normally drill sites); 4. correct identification of specific till units and associated ice movement history; 5. collection of adequately large and representative samples; 6. appropriate sample preparation and processing; 7, appropriate geochemical analyses; and 8. correct data processing and interpretation.While we have no control over the first two geological conditions, and only limited controlover till availability, we can control the quality and thoroughness of sampling, sample identification, sample preparation, analysis and interpretation. In particular attention needs to be focussed on obtaining a large enough sample to be adequately representative, an unbiased sample must be collected, together with appropriate sample processing, analysis, data processing and interpretation. It is considered that by modifying or extending existing approaches to gold exploration the chances of exploration success can be increased. In particular, analyses of both the heavy mineral and minus 63 ?m fractions of till is recommended because gold in till may occur in different size fractions."

Jan 1, 1992

By J. P. Hansen

Reducibility tests were run by the Bureau of Mines on an open hearth lump ore and four groups of pellets whose smelting characteristics had been deter-mined previously in the Bureau's experimental blast furnace. When reduction data from various tests were plotted on specially prepared paper l-(l-percent reduction/100)1/3 against time, the plots were linear. The iron-wustite inter-face therefore advances at a constant rate. The rate of the interface advance in mm/min was used as a reducibility index. The reducibility index measured at 900° C, using 0.45 cu ft hydrogen per minute varied inversely with the surface area of the sample. Even with carefully controlled surface areas, how-ever, duplicate reducibility indices varied considerably. When enough tests were run to give a stable mean, the mean reducibility index did correlate with blast furnace production for the four pellet groups. Results indicated that if the interface speed itself were to be used for correlation with blast furnace production, a sample size of about 180 grams of minus 0.742-plus 0.525-inch particles should be used with a test temperature of 900° C and a flow of 0.45 cu ft hydrogen per minute.

Jan 1, 1966

By Gregory M. Molinda

Coalbed discontinuities historically have been hazardous to mining as well as obstructions to efficient production. An effective means of mapping these features is needed in order to plan safe and efficient mine development. This Bureau of Mines report discusses the use of surface seismic techniques for this purpose. At a southwestern Pennsylvania mine, a system of coalbed discontinu-ities (paleochannels) was accurately mapped by the Bureau of Mines using borehole log methods and underground observation. This site was chosen to test the value of a high-resolution surface seismic reflection on technique for coalbed mapping. A statistical study performed at this mine indicated that the probability of accurately delineating this paleochannel system with conventional borehole methods was remote. A total of 1.47 miles of high-resolution seismic survey, comprised of four seismic profiles, was conducted in known and suspected coalbed discontinuity areas. Several test holes were drilled on the seismic lines in order to evaluate the interpretations. It was found, based on these and other existing boreholes, that it is possible to predict these dis-continuities. Paleochannel washouts were correctly predicted in several instances but in other instances were either incorrectly predicted or not predicted in areas of known discontinuities.

Jan 1, 1988

By N. Arbiter

Fracture under low velocity free-fall and double impact, and under slow compression have been-investigated. The pattern of breakage and the size distribution of resulting fragments for sand-cement and glass spheres have been determined. Photoelasticity methods were used to simulate the stress distributions in free-fall impact in order to explain the observed patterns of breakage. Oblique fracture planes, occurring only in free-fall impact, develop along lines which coincide with the trajectories of principal compression as determined by mathematical analysis Breakage efficiencies for different modes of fracture were compared for both types of spheres. For the same specimen and loading system, static loading and low velocity dynamic loading induce geometrically similar stress fields resulting in reasonably similar fracture patterns and shapes of fragments.

Jan 1, 1968

By A. Eslami

When producing high grade mattes in smelter plants, copper losses in the slag are inevitable. Hence, the recovery of copper from slag has been the focus of many research projects, copper flotation being a widely used process. In the Khatoonabad converter, 200 t/d of slag are presently produced with a grade of 2.3% Cu. Assuming a 85% recovery by flotation, about 3.9 t/d copper could be produced, which is of prime importance economically. In the present work, a sample of this slag was crushed and ground in the laboratory to liberate the copper-bearing minerals. Following mineralogical studies, optimum laboratory flotation parameters were obtained, resulting in 90.27 % recovery and 9.42% of copper grade for the rougher stage. At pilot scale, a pulp of 28% solids was floated at ph 10.5 using 40 git of Z6, 25 git of R407 and 20 git of MIBC and A65. A recovery of 83.52% was obtained for a concentrate grade of 28.36% Cu. In the rougher cells, the feed consisted of particles 94% finer than 74 microns whereas in the cleaning stage, particles were 95% finer than 44 microns. Based on the obtained results, the Sarcheshmeh Khatoonabad converter slag is presently being fed to the Chargonbad flotation plant, where a concentrate of 32% copper at 86% recovery is being produced.

Jan 1, 2007

By Roberto Fustos, Gonzalo Nelis, Víctor Sanhueza, René Gómez

Hang-ups are a challenging operational problem in block caving mines. They interrupt ore flow and imply hang-up removal activities, which take time, increase operational costs, and involve safety risks for workers. In block caving, the number of hangup events of mechanical arches that appear in the drawbell could be decreased if the drawbell geometry is adequately designed based on the expected rock fragmentation. Here, we compile and analyze hang-ups reported in several block caving mines to evaluate the impact of drawbell geometry, rock size, and vertical load on hang-up frequency at the mine scale. Results show that the ratios between drawbell length and d80 (dL/d80), between drawbell width and d80 (dW/d80), between drawbell volume and rock volume (VDB/VP), and vertical stress are critical parameters that define hang-up frequency. These findings confirm previous experimental studies, where a decrease in hang-up events is associated with an increase in these ratios. Additionally, these outcomes are used in a support vector machine algorithm to define categories of hang-up frequency. The results of this classification algorithm are presented in diagrams, which can be used to estimate the hang-up frequency in block caving projects.

Oct 15, 2022

By Reinhard Gertl, Soroush Dabiri, Juan-Carlos de Rueda

The Tunnel of Guillermo Gaviria Echeverri, spanning 6.05 miles, will be Latin America’s longest road tunnel, is currently under construction in Colombia’s Antioquia Department with a single bidirectional tube connected to a parallel rescue tube through multiple cross-passages. The study faces challenges in implementing the prescriptive semitransversal ventilation system due to design restrictions. Different ventilation concepts are eplored to nd the most suitable system for regular operation and re scenarios. A quantitative ris assessment evaluates each alternative system and identies the longitudinal ventilation system, accompanied by ris mitigation measures, as the safest choice, since it surpasses the prescribed semitransversal ventilation concept.

Jun 23, 2024

By J. K. Whyatt

During the past 2 years, U.S. Bureau of Mines (USBM) researchers reviewed an in situ stress investigation conducted in 1977 at a test site on the 4250 level of the Lucky Friday Mine, Mullan, ID. Although the field measurements of over core strain were found to be useful, significant deficiencies were found in the stress field estimation procedure. The stress field estimate was then updated to incorporate recent progress in statistical capabilities and new understanding of stress concentration factors for doorstopper cells, as well as to correct an error in the original stress solution procedure. Simple models were used to examine the possibility that systematic variations in material properties and stress fields existed at the site. These models succeeded in reducing the sum of squared error somewhat, but fell short of completely describing stress variations throughout the test site. This overcore measurement will be supplemented by two other measurements described in the second and third reports of this series. Other observations of stress field characteristics are discussed in the fourth report The final report will also characterize the natural in situ stress field in the vicinity of the Lucky Friday Mine. This work was undertaken to support USBM research on mining method design and rock-burst control for deep mines.

Jan 1, 2010

By Yuchen Wu, Purushotham Thkkaraja, Marek Borowski, Jie Liu, Jianwei Cheng, WANCHENG ZHENG, Yu Wang, Weidong Lu, Gang Zhao, Zhanyou Sa, Huan Yang, Yuhang Wu, Hui Wang

The abstract discusses the importance of gas drainage in coal mines for safety, environmental protection, and resource utilization. It highlights the significance of borehole sealing technology for efficient gas drainage. The study introduces a new inorganic retarding sealing material and investigates its properties, including stability, thermal stability, fluidity, and thixotropy. The material's diffusion performance in cracks is tested using a self-designed system. Field tests in a coal mine demonstrate the material's effectiveness in improving borehole sealing compared to traditional materials.

May 1, 2022

By Ian R. Morrison

"Abstract - The Izok Zn-Cu-Pb-Ag volcanogenic massive sulfide deposit is located 265 km south of Kugluktuk (Coppermine), Nunavut Territory, Canada, in the west-central Slave structural province. The Izok deposit is owned 100% by Inmet Mining Corporation and represents one of the largest undeveloped zinc-copper resources in North America. The Izok deposit is hosted within and near the top of a thick sequence of predominantly felsic pyroclastic rocks of late Archean age. The hanging-wall stratigraphy includes additional felsic volcaniclastic rocks, andesitic and basaltic flows, thin sulfide-rich iron formations, and turbiditic sedimentary rocks. The felsic volcanic rocks are intruded by intermediate dikes and sills, followed by gabbroic dikes and sills. Both intrusive suites are interpreted to be volcanic feeders to the overlying flows. All lithologies are subsequently cut by younger, irregular, granitic pegmatite and diabase dikes. The volcanic and sedimentary rocks are regionally metamorphosed to pyroxene hornfels grade. The massive sulfides occur within a large (kilometer-scale) Na-depleted sericitic alteration zone. The immediate footwall and hanging-wall rocks to the deposit are characterized by zones of muscovite- biotite-sillimanite, lesser chlorite-biotite-cordierite, and locally intense silicification and sodium metasomatism. All lithologies have been affected by younger Ca-metasomatism. As currently defined, the Izok deposit comprises a cluster of five complexly zoned composite lenses: the Northwest, North, Central West, Central East, and Inukshuk lenses. The first four lenses are amenable to open-pit mining, whereas the Inukshuk lens will require underground development. The total indicated mineral resource presently stands at 16.5 million tonnes with a grade of 2.2% Cu, 11.4% Zn, 1.1% Pb, and 60 g/t Ag. Inmet Mining Corporation is presently reviewing the economic feasibility of developing the property."

Jan 1, 2004

By Michael Perlow Jr

A modification of the original Davisson Offset Limit (DOL) is presented for drilled foundations using soil quake (QDOL) factors ranging from 2 to 6. A further modification of the Davisson Offset Limit has also been developed using helical pile soil quake values (HDOL) based upon helix diameter. In addition, the initial tangent slope (IS) of the pile load test displacement curve is used in lieu of the calculated elastic slope (ES) to eliminate many of the uncertainties associated with determining the drilled foundation pile elastic modulus. The QDOL and HDOL load test methods do not require any graphical interpolation and provide easy simple ultimate pile capacity interpretation methods where drilled foundation pile load tests are not carried to plunging failure. Drilled foundation and helical pile load test case studies are presented to demonstrate the use of the modified soil quake QDOL and HDOL Methods.

By Fitterer, G. R.

The impact of the work of Herty "et al" on modern liquid steel technology can only be evaluated by first setting the stage as it existed in 1926. It is important to briefly review not only the steel making process and viewpoints regarding methods of refining, but also to describe the tools which were available for research at the time. One must recall that only 15 years before the beginning of this program, the open hearth production exceeded that of the Bessemer in the United States. Many open hearths were still operating on producer gas (a very inefficient fuel), although some plants were converting to the use of natural gas and very few to oil. Continuous rolling of wide strip started this year. The Faraday Society in England held a World Conference on Physical Chemistry in Steel Making in 1925 and the contributions to this work created considerable interest throughout the world and it appeared that physical chemistry might convert the art of steel making into a science. These papers, however, attempted to solve the problems through the use of the older physical chemical concepts such as Nernst's numbers, etc. and considerable data were missing. In 1923, Lewis and Randall had published their book Thermodynanzicsl and this was later to establish and standardize the steps which are now accepted for the calculation of physico-chemical equations. At the time this research work was started, there were no small high frequency induction furnaces. Northrup had just invented his high frequency furnace and a few large units had been instilled in plants. The vacuum fusion method lor the determination of oxygen in steel was

Jan 1, 1957

By H. C. Cooke

Geological examination of the underground workings of the Horne and Aldermac mines during the summer of 1927 has brought out the following facts: (1) That the ores tend to replace bodies of breccia or tuff rather than massive lava or dyke material; (2) That the faulting and folding at the Horne has had a pronounced effect in localizing the ore-bodies; (3) That there is a tendency in cert?-in cases for ore-bodies to be localized beneath gently dipping dykes, which acted as impervious roofs; (4) That there is a great difference in age between the chalcopyrite part of the ore-bodies and the pyrite-pyrrhotite portion. A statement of the development to date at the Aldermac mine is also included in the paper. ALDERMAC MINE The Aldermac property is made up of eight claims in the western half of Boischatel township, Quebec, including 747 acres in all. The mine itself is approximately three miles, 25 chains from the west boundary, and four miles, 55 chains from the north boundary, of the township.

Jan 1, 1928

By J Vann

Geometallurgy is inherently multidisciplinary and it gains its power to deliver improved outcomes for the minerals industry by bridging silos between disciplines. This cross-disciplinary approach unlocks value, identifies (and avoids) value destruction and provides a pathway to better implementation of an energy efficient and sustainable minerals industry. Despite this promise, we argue that the cross disciplinary approach also represents the greatest threat to the success of geometallurgy. Some key cross disciplinary issues identified are:Geometallurgy has so far evolved in the technical sphere, mainly by collaborations of geologists and metallurgists. Consequently, in many cases the business dimensions and value have not been incorporated. Financial and risk evaluation viewpoints need to be assimilated into the geometallurgical paradigm. In fact, until such measures are integrated into practices, the value cannot be fully demonstrated.The historical and current efforts on geometallurgy have been highly focused on improved sampling and measurement of geometallurgical properties or appropriate proxies. This work has been driven by professional and academic geologists and metallurgical engineers. It is notable that mining engineers (who are critical in the value delivery of geometallurgy through changed planning approaches) have so far been at the margins, or absent. The construction of valid three dimensional (3D) geometallurgical models raises some important organisational, mathematical and geostatistical considerations. The enhancement of resource models to account for geometallurgical aspects must be managed carefully if the full value of geometallurgical thinking is to be realised.The use of 3D geometallurgical models to change business decision making and practices is the real nub of the problem. We believe sophisticated scenario based evaluation methods are required if the potential impacts of spatial rock properties on processes further down the mining value chain are to be realistically evaluated. Such changed practices require ‘whole of value chain thinking’ to embed this change into the business in an ongoing way.Because profitable geometallurgy demands changed approaches to business decision-making and also organisation of the firm (radically changed in some cases), the senior executive viewpoint must be incorporated into the language and thinking of geometallurgy. This is unavoidable if the establishment of a geometallurgical approach to project evaluation, development and operation is to be successful and sustained.A powerful analogy for the problem faced by geometallurgy is the transformation of safety culture in the mining industry in the past 20 years. We argue that, as in the safety revolution, explicit models, cultural change and management of the ‘soft’ dimensions of the problem are pivotal to success of geometallurgy. In light of this, we propose a model (‘the Geomet Curve’) that gives a framework and pathway for geometallurgy in seven steps. The implications of this model for technical and organisational steps required at different stages are discussed.

Sep 5, 2011

By Lucas Tedesco Bolzan

Blindagens contra armas de fogo são de grande importância para proteção do homem, no contexto atual de violência urbana e conflitos armados. Destacam-se os sistemas de blindagem multicamada (SBMs), constituídos por materiais diferentes, pelo seu bom desempenho e menor peso. Um SBM típico é constituído de uma camada cerâmica frontal, uma segunda camada de compósito e uma camada posterior de metal dúctil. Apesar de serem tipicamente fabricados em materiais sintéticos, uma alternativa é a utilização de compósitos reforçados com fibras naturais como segunda camada. Este trabalho tem como objetivo verificar a eficiência de SBMs que utilizam compósitos de poliéster com 30%vol. de fibras ou tecido de sisal. Foram realizados ensaios balísticos com munição 7,62 mm, e verificou-se que os SBMs com fibras e tecido de sisal se enquadram no critério da norma internacional (NIJ 0101.06), de resistir ao impacto balístico e imprimir deformação menor que 44 mm no material de referência (plastilina), além de manterem sua integridade após o impacto.

Aug 17, 2017