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By Dan Brown

This paper presents a case study of a cyclic lateral pile load testing program performed on two 18-in square prestressed concrete piles (PSC) in Savannah, Georgia. The load test program was developed to simulate the lateral behavior of a single pile under seismic loading conditions for the design and construction of a large LNG storage tank. The lateral load tests included cyclic loading to measure possible degradation in soil response followed by static loading to large displacements (around 6 inches at the loading point). The lateral load was applied through a reciprocating jack positioned to push and pull the piles against each other. The test piles were instrumented with multiple displacement transducers, downhole inclinometer, and strain gauges. This paper provides an interpretation of the test results regarding the pile performance and soil response to monotonic and cyclic lateral loading. A backfitted computational model of the soil resistance was developed to match the test results using the LPILE computer program. The load-deflection and deflection/moment versus depth comparisons suggest that this model appears to capture the behavior relatively well within the general range of suitability for design purposes. New design curves were developed based on the soil parameters derived from the lateral load test results.

Jan 1, 2003

By Steven M. Rupprecht

"The artisanal mining sector in Central Africa is largely informal, yet provides an essential livelihood for many (directly or indirectly) participants, as well as facilitating an important source for the flow of income into many communities. Artisanal mining varies from site to site, but appear largely well structured despite its informality. The artisanal mining sites in Central Africa have some inherent management structure and the extraction itself is often organised. Artisanal mining is labour intensive and is generally conducted utilising hand digging methods e.g. shovels or hand chisels. Artisanal mining is generally more dangerous than small-scale or large-scale modern mining operations. This is especially true as artisanal operations are generally subsistence activities with artisanal miners focusing more on immediate concerns than the long-term consequences of their activities. When miners have no other source of income, they will usually find ways to evade controls and carry on working. The objective, through proper/dedicated training of artisanal miners is to migrate Artisanal mining to establish a small-scale mining (SSM) industry in Central Africa. Through developing the necessary skills in the fundamental areas of mining it is proposed that Artisanal Mining can become more productive and safer mining operations. The paper reviews the above focus areas, highlighting the skills and tools that are necessary to assist in establishing a sustainable small scale mining industry migrating from manual labour to semi-mechanised mining and processing. The purpose of the transformation process is to create a safe, healthy, environmental and community oriented mining operation with the objective to uplift the skills and wealth of the mineworkers and the general community."

Jan 1, 2015

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006

By Diankun Lu, Ganfeng Tu, Edouard Asselin, Feng Xie

A novel separation process for detoxifying cadmium-containing residues arising from zinc hydrometallurgical processes has been developed. An initial investigation indicated that a high concentration of zinc in the sulfate solution can be effectively separated from cadmium by solvent extraction with P204 (di(2-ethylhexly)phosphoric acid, D2EHPA). The mixture of sulfuric acid and ammonium citrate ((NH4)3C6H5O7) is thus used to extract metals from the residue at room temperature. Copper in the leachate is recovered by solvent extraction (SX) with LIX 973. Cobalt in the raffinate from the copper SX process is recovered by precipitation with a-nitroso-ß-naphthol. The results show that more than 50% of the copper and virtually all the zinc, cadmium and cobalt in the residue can be leached under the experimental conditions used here. Virtually all dissolved copper and cobalt can be recovered in the subsequent solvent extraction and precipitation processes. The presence of (NH4)3C6H5O7 could significantly facilitate the extraction of zinc by D2EHPA in the subsequent separation of zinc and cadmium. More than 97% of the dissolved zinc can be recovered through a two-stage counter current solvent extraction process. After separating copper, cobalt and zinc, cadmium can easily be recovered from the solution either by cementation with zinc powder or by electrowinning, while the purified solution can be recycled back to the leaching process.

Jan 1, 2014

By Junfeng Shen

Geosynthetic clay liner (GCL) is a kind of waterproofing material used widely in engineering. The waterproof mechanism is understood in terms of bentonite particles becoming a water-obstructcolloid layer after they absorb water and swell. The swell stress, however, has not been determined directly till now. In our experiment, the swell stresses of the GCL under saturated and water absorbing conditions are measured directly using a custom-made instrument. The results show that (1) the instrument designed by the authors performed satisfactorily and the test results are reproducible; and, (2) The trend line of swell stress variation with time can be divided into three segments. The first segment is characterized by a quick increase of the swell force in the first 0?50 hours. The swell stress increases by 7.00×10-4?1.00×10-3 Mpa / hour. The second segment shows a slow increase of the swell stress during the 50?1730 hours. The swell force increases by 7.54×10-6?2.02×10-5Mpa / hour. The third segment is characterized by little variation in the swell stress after 1730 hours. In this segment, the average value of the swell stress measurements is 0.0719Mpa and the maximum value is 0.0729Mpa. It is suggested that the swell stress is mainly raised by water entering the pores among montmorillonite particles and the interstitial layers in individual montmorillonite crystals, leading to an increase in volume and manifested as a stress on the surrounding materials.

Jan 1, 2006

By K. G. Thorne, D. R. Lentz, A. F. Park

"The Main zone of the Clarence Stream gold deposit is hosted by a shear zone adjacent to the Saint George batholith in southwestern New Brunswick. The mineralization history relates to progressive deformation in the shear zone and the intrusion of the Magaguadavic granodiorite.Of three phases of deformation that have affected the area (D1-D3), D1 is not observed in the Clarence Stream shear zone. Two suites of igneous rocks intrude the shear zone: post-D2, pre-D3 gabbro; and granitic dikes, which crosscut the gabbros. Granitic dikes show a diverse range of relationships to D3 features, from pre-syn-D3 mylonitic fabrics in transposed and highly deformed enclaves, to nondeformed and entirely discordant dikes (post-D3).A variety of veins occur within this shear zone. Zoisite-bearing and later, crosscutting epidote-bearing veins are preserved as relics in quartz-mylonites, and predate quartz veins that host gold mineralization. The epidote-bearing veins are associated with pseudotachylitic cataclasite dikes, consistent with transient brittle failure during ductile deformation.Deformation relates to right-lateral strike-slip motion across the shear zone, and subhorizontal and near-vertical stretching lineations imply transpression. A late (late- or post-D3) dip-slip phase of motion is also apparent, and cooling followed a metamorphic peak early in D2-D3 history. Deformation of the shear zone, and more localized transient brittle failure, provided the permeability for fluid movement and vein emplacement. This scenario is similar to the findings of other studies, in which geochemical, tracer isotopic, and age-dating (U/Pb, 40Ar/39Ar) results suggest that the adjacent Magaguadavic granodiorite provided heat and metals. La zone principale (Main zone) du gisement d’or de Clarence Stream est encaissée par une zone de cisaillement qui longe le batholite de Saint George dans le sud-ouest du Nouveau Brunswick. L’historique de la mise en place de la minéralisation accorde un rôle important à la déformation progressive dans la zone de cisaillement et à la mise en place de la granodiorite de Magaguadavic.Des trois phases de déformation à avoir affecté la région (D1-D3), les effets de D1 ne sont pas observés dans la zone de cisaillement de Clarence Stream. Deux suites de roches ignées se sont mises en place dans cette zone de cisaillement : un gabbro post D2, pré-D3 et des dykes granitiques qui recoupent le gabbro. Les dykes granitiques montrent une grande diversité de relations avec les structures D3, allant de précoces à synchrones aux fabriques mylonitiques D3 dans des enclaves transportées et fortement déformées à des dykes complètement discordants et non déformés (post-D3).On note diverses veines dans cette zone de cisaillement. Des veines contenant de la zoisite ainsi que des veines d’épidote sécantes plus tardives, lesquelles sont préservées comme reliquats dans les mylonites à quartz et sont plus vieilles que les veines de quartz contenant la minéralisation aurifère. Les veines d’épidote sont associées à des dykes de catacalasite à texture de pseudotachylite, compatibles avec une rupture cassante épisodique durant la déformation ductile.La déformation résulte d’un mouvement décrochant dextre le long de la zone de cisaillement et les linéations d’étirement subhorizontales et quasi-verticales impliquent de la transpression. Une phase tardive (tardi- ou post-D3) de mouvement selon le pendage est aussi apparente, et le refroidissement succède à un pic métamorphique tôt dans l’histoire D2-D3. La déformation de la zone de cisaillement et la rupture cassante épisodique ont fourni la perméabilité nécessaire au mouvement des fluides et à la mise en place des veines. Ce scénario est similaire à celui proposé par d’autres études, dans lesquelles les résultats de géochimie, de traceurs isotopiques et de géochronologie (U/Pb, 40Ar/39Ar) suggèrent que la granodiorite de Magaguadavic avoisinante a fourni la chaleur et les métaux."

Jan 1, 2008

By R. Armstrong

Due to limited available level ground, Nkomati Nickel Mine cut a weathered rock slope at the base of a mountain spur in order to create a platform for construction of the primary crusher plant and run-of-mine stockpiles. As space is limited around the mining area, ore processing at Nkomati is based on a high reliability of flow of material through the crusher plant, with minimal usage of other and larger designed stockpiles. Evidently, any crusher plant shutdown will render the mine as a whole unproductive and put excessive strain on the medium- to long-term large ore stockpiles, the deposition rates for which are restricted by founding material consolidation requirements. At the onset of the 2012 rainy season, movement was identified on the slope monitoring system and cracks developed on the slope. After a minor failure on the crusher slope an assessment of the slope stability was conducted and a slope management plan recommended, which included deployment of real-time monitoring. An evaluation of the conditions leading to instability was conducted and the likely causes for the failure identified. A full evaluation of the slope monitoring, rainfall, and mining conditions was undertaken and movement triggers were determined. This paper describes the events leading to the development of the failure and the evaluation of the monitoring data to determine a management plan for the failure that allowed for minimal shutdowns of the primary crusher.

Jan 1, 2014

By Shigeru Tsutsumi

The rapid development of transportation facilities in Japan focused the attention of this country on the possibility of converting the existing coal resources (of which there was an abundance) into liquid fuels, for which there was a constantly increasing demand. Previous work had indicated that this could be accomplished by utilizing one of two processes - the Bergius process, in which high temperatures and high pressures were employed to effect direct liquefaction of the coal, and the Fischer-Tropsch process, in which an indirect liquefaction of coal was accomplished by the production of liquid hydro-carbons from hydrogen-carbon monoxide mixtures. This report describes some investigations into the latter process, which was first developed by Fischer and his colleagues in the Coal Laboratory in Muhlheim, Germany, in 1923. By 1932, these investigators had achieved a 60-percent theoretical yield (152 ml. of liquid hydrocarbons per cubic meter of 2H2:ICO synthesis gas) by using a precipitated Co-Th02 catalyst.3/ At the same time (1932), Dr. Kita of Kyoto Imperial University and Messrs. Fujimura and Tsuneoka obtained 145 ml. of gasoline (C5+) per cubic meter of synthetic gas by using a Co-Cu-Th-U catalyst. 4/ This report is a description of the experimental results subsequently obtained at the Fuel Research Institute, Kawaguchi City, Saitama, up to 1935.

Jan 1, 1951

By C. N. Harman, N. S. S. Rama Rao

Production of Ferro-alloys through submerged electric arc furnace involves use of electric power as one of the major inputs. Hence the production by this power intensive process can be made economically more competitive if the specific power requirement for smelting each ton of the product is brought down. This becomes all the more necessary where the power cost is comparatively high, like in India. Since the day FACOR started production of Ferro Chrome in 1968, briquetted chromite fines along with lumpy ores were used as feed. Subsequently the increase in the proportion of briquettes and reduction in lumpy ore helped in increasing the use of chromite fines and also brought down the specific power requirement. Meantime FACOR had been closely watching the technical development of use of sintered pellets in Outokumpu and SRC Processes which need still lower specific power. But the high capital requirement for a pelletisation plant kept FACOR from introducing pellets feed to their Ferro chrome furnaces. So this was postponed to be adopted in future. In February 2004 in the ?1st Ferro-Alloys India?, a paper [1] was presented by Dr. Amit Chatterjee. In the questions period after the presentation of the paper there came up a discussion in which it was revealed that with the Indian high grade chrome ores it was not possible to make sufficiently strong pellets, unless a larger percentage of bentonite is used as binder. This is because the Indian high grade Chrome ores have different mineralogy of gangue content compared to low grade ores in Finland and South Africa. Higher usage of bentonite gives rise to higher slag volume and this would result in increased specific power. Since FACOR had plans to go in future for sintered pellets feed, this gave rise to a doubt on success of pelletisation for Indian high-grade chrome ores. This prompted FACOR to take up experimental production of sintered chromite pellets and use of the same in one of their existing furnaces for production of high carbon Ferro chrome. The results are encouraging and are summarized in the paper.

Jan 1, 2007

By J. F. Burr, D. P. Snyder, G. W. Luxbacher

"The Mine Improvement and New Emergency Response Act (MINER Act) of 2006 (PL 109-236, 2006) established the Office of Mine Safety and Health, functioning as the Office of Mine Safety and Health Research (OMSHR) within the National Institute for Occupational Safety and Health (NIOSH) and provided authority for awarding contracts related to the development and implementation of new mine technology and equipment. The OMSHR external contracts program was formed in accordance with the MINER Act and has since issued more than 150 contracts focused on worker health and safety. Initial funding for this program was provided by the United States Congress through two emergency supplemental appropriations and was focused on emergency oxygen supply, communications and tracking, and refuge chambers (also referred to as refuge alternatives). Since the MINER Act, Congress has continued to fund the program through the annual NIOSH mining appropriation. The program was supplemented starting in 2009 with an academic capacity building program directed toward developing university tenure-track faculty and facilities and supporting graduate students in the area of mine ventilation. Ground control was added as an additional focus area in 2011. A short synopsis of each contract is published on the NIOSH Mining website (www.cdc.gov/niosh/ mining/researchprogram/contracts/index.html) and final reports are available in digital form on request. A summary of the progress OMSHR has made over the 10-year period since the Act was published previously (Snyder et al., 2016).External contracts are broadly classified by the following areas:• Communications and tracking.• Emergency response.o Self-escape and breathing air supply.o Refuge alternatives.o Escape and rescue.• Equipment safety.• Fires and explosions.• Ground control.• Mine environmental systems (mine ventilation and atmospheric monitoring).• Worker/workplace health and safety.Contracts are issued under a request for proposal (RFP), through a broad agency announcement (BAA) or under an interagency agreement (IAA). An RFP solicitation includes a specific problem description and a well-defined scope of work to guide the offeror in preparing a bid to conduct the research. Under the BAA several problem areas are described and the offeror develops the scope of work and deliverables for the proposed research. An IAA is very similar to an RFP except it is a contract between two federal government agencies."

Jan 10, 2018

By Todd Wanless

This paper addresses the challenges experienced by the designer and three government agencies during implementation of major improvements for the Turkey Creek Tunnel in Kansas City, Kansas. The tunnel serves as a vital stormwater conveyance system for upstream flood control. Major structural deficiencies were identified within the tunnel including complete loss of sidewall and invert. Without immediate attention, complete loss of the tunnel arch could lead to blockage and extensive remedial repairs under difficult conditions. Considering that tunnel flows must be maintained during construction, a phased design and construction process has been implemented to expedite stabilization of the erosion cavities followed by tunnel liner repairs.

Jan 1, 2008

By S. Leong

This paper reports on research examining disclosures from mining companies regarding their water usage in the Macquarie and Lachlan catchment areas, both parts of the Murray-Darling Basin in New South Wales, Australia. The objective of the research was to assess whether this disclosure is sufficient to allow communities to determine whether mining companies are complying with mining conditions of consent and abiding by the requirements of their water licencing agreements. These requirements are then compared to the water reporting requirements of the Global Reporting Initiative (GRI) and the Water Accounting Framework for the Minerals Industry (WAFMI). Communities are concerned about whether the mining industry?s use of water will have impacts on their livelihoods and lifestyle and thus require information concerning the quantity of water that will be extracted, how much water will be left for other stakeholders and whether the mining will affect water quality. This is an archival study. It has involved examining relevant publically available information released by mining companies and government regulators and determining if this is sufficient to meet the needs of the local communities. Additionally, it has involved looking at information indirectly provided by mining companies, via the use of intermediaries. Further, information availability concerning basic water accounting and regulatory breeches and whether such information is available at the mine site level has been considered. It is found that while NSW legislation places very little reporting requirements on mining companies, the development consent conditions for new projects and extensions to existing projects are quite significant and should be sufficient to meet the needs of local catchment residents though such information is not always easily accessible for the layperson.

Aug 1, 2013

By M. Abdellatif

Keywords: Magnesium, pyrometallurgy, Mintek Extensive testwork on atmospheric thermal magnesium production has highlighted certain important fundamental and operational factors that have a major influence on magnesium extraction and its extraction rate, the condensation efficiency of magnesium, as well as on the quality of the condensed metal. The possible impact of these factors on the selection and preparation of raw materials, recipe choice, furnace electrical energy consumption, and on the refining requirements of the crude magnesium is discussed. Selected pilot plant operational and metallurgical data are also presented.

Jan 1, 2006

Project Located in northwestern British Columbia 70km West of Cassiar Highway Galore Creek Project and Road Access Corridors Designated For Mineral Development in Stikine-Cassiar Land Resource Management Plan (LRMP)Approved in 2000Strong BC Government, local community and Tahltan First Nation Support for Project

May 1, 2006

By Sergio N. Monteiro

Polymeric composites reinforced with natural fibers are increasingly been used in several engineering applications, from automotive parts to building construction elements. In addition to the relatively low cost, the natural fibers are also appraised by their renewable and biodegradable characteristics. Fibers extracted from the crust of coconut fruits, also known as coir fibers have been investigated for a possible use in composite materials. In the present work, the coirfiber/polyester matrix interfacial strength was evaluated by means of pullout tests. The variation of the pullout tensile stress vs. the embedded coir fiber length permitted to determine the critical fiber length and, thus, to calculate the interfacial strength. Observations by SEM complemented the results from pullout tests, indicating that coir fibers have a potential for application aspolymeric composites that could replace conventional materials such as wooden and gypsumpanels.

Jan 1, 2006

By Tim O’Neil

Dressed in black tie and Victorian attire, some 200 people came to Leadville, CO, for a September weekend featuring a National Mining Hall of Fame and Museum (NMHF&M) induction banquet and a scenic mountain train trip to Fremont Pass and the Climax Mine. The 18th annual induction banquet on Sept. 17 began with cocktails and a open house. It was a chance for visitors to tour the National Mining Museum including the new Hennebach Wing, opened in February. The new wing is named in honor of Ralph Hennebach, retired chairman of Asarco. Formerly Leadville Junior High School, the Hennebach Wing encompasses more than1,440 m2 (15,500 sq ft) of floor space in two stories. One prominent feature is a 1923 Wills Sainte Claire touring sedan. Climax Molybdenum donated this first all-molybdenum steel motorcar. Docents were available throughout the museum to give banquet attendees directions and answer questions.

Jan 1, 2005

By Shail J. Butani

In 1986 the Bureau of Mines conducted a probability sample survey, Mining Industry Population Survey, to measure such employee characteristics as occupation; principal equipment operated; work location at the mine; present job, present company, and total mining experience; job-related training during the last 2 years; age; sex; race; and education. The population estimates are necessary to properly analyze the Mine Safety and Health Administration (MSHA) injury (includes illness and fatality data) statistics; that is, to compare and contrast injury rates for various subpopulations in order to identify those groups that are exhibiting higher than average injury rates. This report uses the survey's results to characterize the U.S. sand and gravel mining workforce from March through September 1986. Similar reports have been prepared for the metallic, stone, and nonmetallic mining industries, as well as for the entire metal and nonmetal mining (includes metallic, stone, sand and gravel, and nonmetallic industries) sector and the coal mining sector.

Jan 1, 1988

By George H. Johnson

This report describes the procedures and summarizes the results of an investigation of surface subsidence above caving blocks at the San Manuel mine, San Manuel, Ariz., in order to obtain quantitative information on subsidence and ground movement caused by mining large volumes of ore. This investigation is one part of an overall study of rock mechanics being undertaken by the Bureau of Mines. Attention was given to the improvement of a rapid and precise method of surveying a large number of subsidence pins and cracks in the surface terrain. Photogrammetric methods were used as an adjunct to the triangulation subsidence surveying as well as in ordinary topographic work Maps of various kinds were prepared to show the results obtained. The computation of the survey notes was programed for an electronic digital computer at a saving of time and expense over the use of a desk calculator and trigonometric tables.

Jan 1, 1963

By K. T. Stafford, N. A. Iverson, V. T. McLemore

Southwestern New Mexico is part of a large belt of Late Cretaceous to Eocene copper porphyry deposits found in Arizona, New Mexico, and Mexico. These deposits are the result of arc magmatism that occurred during the Laramide orogeny. Recently, attention has been brought to other commodities that can be extracted as by- and co-products, many of which are critical minerals. A new compilation of the geochronology of these deposits shows two main pulses of magmatism that produced mineralized deposits and, along with new dates by the author, shines new light on the geologic history of these deposits and the role it plays in critical mineral abundance.

Feb 1, 2024

By W. R. Hardwick

This paper describing the mining methods of the Inspiration Consolidated Copper Co. is one of a series being prepared by the Bureau of Mines on mining methods and costs in various mining districts of the United States. The story of mining at Inspiration is of particular interest because, after 127,812,000 tons of low-grade copper ore were successfully mined, the mining method was changed from block caving to open-pit. As the open pit became deeper, many features of the former block-caving operation that were exposed elucidated concepts of the mechanics of caving that previously had been assumed but not observed. The conversion to open-pit mining was accomplished by unique combinations of equipment and the introduction of ingenious engineering and operating practices that have extended the expected life of the mine for many years.

Jan 1, 1963