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The schlieren technique describes an optical analysis method designed to enhance light distortions caused by air movement. The ability to visualize air flow has significant implications for analyzing underground mine ventilation systems, including the enhancement of surveys and models. Currently, traditional schlieren methods are impractical underground. Background oriented schlieren (BOS) provides a solution to this problem. BOS requires two primary components, a professional quality digital camera and a schlieren background. A schlieren background is composed of a varying contrast repetitive pattern, such as black and white stripes. This background allows the camera?s sensor to capture minor light diffractions, such as those caused by air flow. Although BOS shows great potential for ventilation analysis, sensitivity is an issue. This paper seeks to validate the BOS technique for imaging flow through a regulator by comparing BOS images with traditional schlieren images. This paper also outlines initial experimental efforts used for the validation.

Jan 1, 2011

By Neil T. Davie, Thomas K. Blanchat, Thomas C. Togami, Joe R. Weatherby, Dale S. Preece, Robert A. Benham, James J. Calderone

"Geotechnical structures ,such as underground bunkers, tunnels, and building foundations aresubjected to stress fields produced by..the gravity load on the structure and/or any overlyingstrata. These stress fields may be.. reproduced on a scaled model of the structure byproportionally increasing the gravity field through the use of a centrifuge. This technology canthen be used to assess the vulnerability of various geotechnical structures to explosive loading.Applications of this technology include assessing the effectiveness of earth penetrating weapons,evaluating the vulnerability of various structures, counter-terrorism, and model validation. Thisdocument describes the development of expertise in scale model explosive testing ongeotechnical structures using Sandia’s large scale centrifuge facility. This study focused onburied structures such as hardened storage bunkers or tunnels. Data from this study was used toevaluate the predictive capabilities oft existing hydrocodes and structural dynamics codesdeveloped at Sandia National Laboratories (such as Pronto/SPH, Pronto/CTH, and ALEGRA)."

Jan 1, 1998

By A. W. Dickerson, G. Hollier, F. A. Bartley

Following on from many years of research aimed at improving the effectiveness of truck haulage operations in mines operated by BHP Minerals, BHP Research developed a concept for an Innovative Large Mining Truck, (ILMT) which has the potential to significantly improve the cost effectiveness of rear dump mining trucks. The ILMT concept reduces the empty vehicle weight dramatically, greatly reduces unequal rear tyre loading and improves ride and handling characteristics. The concept has been taken to the "proof of concept" prototype truck stage with the cooperative efforts of BHP Coal, BHP Research. Liebherr Mining Truck, Inc., Liebherr-Australia and Birrana Engineering. Testing of the prototype truck commenced at a coal mine in Queensland, Australia during May, 1996. Preliminary results from the testing program are very encouraging. Expectations are being met and in some cases exceeded.

Feb 24, 1997

By J. Jonas, J. M. Harrington, K. Wangerud, S. D. Fundingsland, J. G. Harrington

EPA NRMRL Mine Waste Technology Program and Region VIII Superfund office are jointly conducting an in-situ technology demonstration at the Anchor Hill Pit Lake, Gilt Edge Mine Superfund site. The goal is to develop in-situ treatment cost/performance data for potential application in long-term water treatment/management at Gilt Edge and similar sites. The pit contained 77,000,000 gallons of pH 3water with elevated metals, sulfate, and nitrate. The Green World Science® patented process for in situ treatment was implemented to isolate and sequester metals; create stable long-term water quality and restore a sustainable ecosystem. COCs have decreased more than 99%, and dissolved discharge standards were attained.

Jan 1, 2004

By R Simcock

Why Rehabilitate? Legislative Requirement Land rehabilitation is a condition of resource consents for mining. Clause 17 (1) of the Resource Management Act 1991 (duty to avoid, remedy, or mitigate adverse effects) provides the legislative basis for local authorities to impose resource consent conditions requiring land to be rehabilitated to approved uses during and after mining.

Jan 1, 1997

By D. B. Rebuli

Seismic networks in deep gold mines of South Africa are often planar owing to the tabular geometry of the orebody and, therefore, the mining infrastructure. Consequently, seismic event locations are poorly constrained in the direction perpendicular to the reef plane, and symmetrical locations above and below the reef plane may fit the observed data equally well. This problem may be resolved in situations where the strata above and below the reef plane have significantly different seismic velocities, which is the case for the Ventersdorp Contact Reef at Kusasalethu mine (previously Elandskraal, the amalgamation of Deelkraal and Elandsrand). A location method using a layered location model that takes into account the velocity contrast between the layers was tested. Observed direct- and head-waves were used to determine the velocity bounds of the P-wave velocities in the two-layer model. The data-set was also used to find the best P- and S-wave velocities for the two layers by grid searching over a range of velocities and minimizing the sum of the travel-time residuals. The results from the grid search and those from the calibration of velocities using direct- and head-waves give similar P-wave velocities for each of the two layers. A second set of seismic events was then relocated with this layered model and locations closer to reef were found. This simple layered location method goes some way to reduce the reefperpendicular location errors for Kusasalethu mine in particular. Keywords mine seismology, velocity model, location methods.

Jun 1, 2013

By Adam Powell, Matthew Earlam

INFINIUM, Inc. is scaling up a new molten salt electrolysis process for producing rare earth metals. Instead of conventional carbon anodes, this process uses Pure Oxygen Anodes™ which employ a stabilized zirconia solid electrolyte between the molten salt and anode. This eliminates two problems with today's rare earth metal production technology. First, it eliminates carbon anodes and contamination of the product by carbon and its impurities, enabling 10-100 times larger batch size than current practice, and lower labor costs. Second, it eliminates emissions of perfluorocarbons (PFC) such as CF4 and C2F6, which are very problematic greenhouse gases with 6000+ times the global warming potential of CO2. The zirconia also enables a sealed vessel with no LiF emissions, creates a reducing environment enabling use of low-cost welded steel vessels, and either produces a high-purity oxygen by-product or can use natural gas to reduce the necessary electrical energy with no HF production. This paper will describe the technology and its current status for rare earth metal production.

Jan 1, 2014

By L. P. James, W. W. Atkinson

Utah has produced about one billion troy oz. (31.7M tonnes) of silver, more than any U.S. state except Idaho. Several very high grade ore systems, now closed, occur within large polymetallic limestone-hosted districts related to plutonic complexes. These Utah mines fed several major lead smelters for nearly a century. Interaction of magmatic chloride-rich fluids with carbonate rocks localized significant bonanzas within these districts. A low sulfidation state was produced in the fluids by their passage through limestones. The Bingham porphyry mine has also yielded more byproduct silver than other porphyry copper-gold systems. Away from exposed intrusive rocks, some large silver-only systems occur in Mesozoic sandstone and in caldera-related veins in volcano sedimentary rocks. Thick permeable latest-Proterozoic basement meta quartzite sequences present beneath western Utah may have been important, as perhaps they were in the Coeur d’Alene district of Idaho, in providing chloride and silver-rich ore fluids. However, it is clear that specific Tertiary magmatic events played an essential role in the evolution of the Utah silver-rich metallogenic province. The largest silver districts in the state are genetically related to porphyritic plutonic rocks.

Jan 1, 2000

I had hoped when the time came for me to address this meeting that gold mining would be in a much happier position than we find it to-day.As it is, and because of the demands of national security, we find this great and valuable primary industry relegated to the background and in danger of temporary extinction.These notes refer mainly to gold mining in Western Australia, whence comes the major portion of Australia's production, and their purpose is to record a brief review of the industry immediately prior to the general disorganization that is following the call-up of men from the mines.During this period of reduced production the loss of comparable statistical data will make it impossible to follow the progress of the industry, and, since the period may be long, it occurred to me that information might be derived from an examination of the trend of recent production that would indicate what may be expected of the industry when full production is resumed in the future.Since the revival of gold mining, which started in 1931, most of the old-established mines have reorganized and, in some cases, completely renewed and enlarged their equipment in order to achieve maximum production, and old mines hitherto unpayable have been re-opened and equipped. At the same time large sums have been spent in scientific prospecting and in search for new mines, and it is safe to say that at the end of 1939, when gold production reached its peak, practically every known mine in Western Australia that could be worked profitably was in production.During this period the number of men employed in the industry rose from 5,961 in 1931 to approximately 15,000 in 1939. From the outbreak of war in 1939 to the end of 1941 the output from the mines was maintained at full pressure, maximum tonnage beingrecorded in 1940, although a reduction in the grade of ore treated caused a slight falling off in gold production.During 1941 there was a. fall in both tonnage and grade. The decline in tonnage was due partly to the closing of the Lancefield and Mount Magnet mines, and partly to the shortage of labour brought about by the response of the goldfields to the call for men for the fighting services, the average number of men in the industry in this year being reduced to 12,929.With the entry of the United States into the war in December last and the pooling of the resources of the allied nations, the need for gold as a purchasing medium passed, and with its passing there arose the demand for the transfer of the man-power engaged in gold mining to other fields of industry directly connected with the war effort.There was a ready response by those connected with the industry who...

Jan 1, 1942

By Michael Day, Paul Kos, Scott Brinton

A hydrogeologic characterization and impact analysis was performed for a proposed quarry at the Hitch Rack Ranch located in the Little Turkey Creek watershed southwest of Colorado Springs, Colorado. Continuous multiple channel tubing, nested piezometers, stream flow measurements, and mapping of known seeps were used to define the three-dimensional potentiometric distribution and areas of groundwater recharge and discharge. Water balance considerations, mass balance calculations, and potentiometric response to earth tides and barometric fluctuations confirmed that the granite fracture system in the ridge area of the proposed quarry has an extremely low bulk hydraulic conductivity resulting in minimal groundwater discharge to sustain the baseflow of Little Turkey Creek. The Little Turkey Creek valley forms the major conduit for groundwater flow exiting from the upper part of watershed underlain by granite. This conclusion has significant implications with respect to mine planning to minimize projected impacts to the hydrologic system and preserve this recharge component to downgradient Denver Basin sedimentary deposits.

Models are used in engineering to reproduce reality as faithfully as possible so that the expected response of a system for given actions or inputs can be determined. In the field of rock engineering, both empirically based and numerical models are widely used to determine the likely response of the rock surrounding excavations. Many of the empirical models are developed from statistical analysis of case histories or from direct observation; however, empirical models are limited because they should be used only within the range of conditions of the observational database. Synergy exists between empirical and numerical models, because empirical models can be used to calibrate and validate numerical models. The empirical approach can benefit from the capability of numerical models to investigate specific mechanisms, which would not be possible using observations alone. Two cases are presented in which the synergy between empirical and numerical models is demonstrated. The first case examines the analysis of discontinuity effects on the strength of slender pillars in limestone mines, and the second case evaluates the effects of stress orientation on coal mine entry stability. It is concluded that numerical model calibration and verification comprises an important first stage in the successful application of models in rock engineering design. Application of numerical models allows mechanisms and interactions of various parameters to be analysed, greatly improving the understanding of the system. The improved understanding can be used to extend the application of empirical design methods, resulting in improved safety and efficiency of rock engineering designs.

Jan 1, 2014

By V. M. Shick

With gentle bedding within the zone of support pressure the delamination in roof rocks may occur only on those stratification planes where cohesiveness of rock is close to zero. Unlike this, at dip angles of more than 30-35° disintegration of rock occurs on the surfaces with cohesion up to 5 MPa. Therefore, the delamination in roof rocks at inclined beds is greater than at gently dipping ones. The original disintegration along the pressure fissures with the formation of block structure at inclined strata is not typical, and it may be observed only in roofs with included thick rocks; in this case, the orientation of fractures depends on the angle of seam inclination. Deformation of roof roocks above the mined-out space is determined by anisotropy of layers stiffness (hardness). With the increase of dip angle the own bearing capacity of layers will rise in the direction of strike. It was emphasized that the natural and technological factors are of great importance for rock pressure manifestation in longwalls.

Jan 1, 1996

Circulating Air Classification of Manufactured Sand Due to environmental concerns, the supply and use of natural gravel has been limited by the Swedish government. The Swedish concrete industry is therefore examining manufactured sand as an alternative that has equal or better product quality, and which the Swedish quarry industry already has the ability to deliver. However, in order to comply with the specifications set by the concrete industry, a better means of classification is needed, as the proportion of fine particles (filler) smaller than 63 - 125 ¦m in size must be reduced. One classification technology that meets the requirements may be air classification. This paper examines the process of circulating air classification, which is not yet commonly used in the Swedish quarry industry; suggesting that a better understanding of the process is needed. The circulating air classifier in this study has two internal machine parameters that can affect the separation point; namely, the speeds of the circulating fan and the separator fan. We study their effect on the separation point as well as the interaction between these parameters. Full-scale parameter tests are also conducted, in which size distribution is measured before and after the circulating air classification. This study shows how the different parameters affect the separation point and that it is possible to produce manufactured sand according to specifications. Computational fluid dynamics (CFD, Fluent) is used to study the internal flow of the air circulating within the classifier. A single-phase study of the flow field is conducted to support and explain the findings from the full-scale tests.

Sep 13, 2010

By Dave Marsh, John Goode, Niels Verbaan, Kevin Bradley, Henrie Notzl

The mineralogy of the Avalon Nechalacho deposit is complex with significant fractions of HREEs, Zr, and Nb found in refractory minerals such as zircon and fergusonite. Sulphuric acid baking followed by water leaching can be used to extract REEs from flotation concentrates, but acid baking does not completely "crack" the zircon and fergusonite, so the extractions of Zr, Nb, and HREEs are not high. An alternative flowsheet has been developed that is able to obtain significantly improved extractions of HREEs, Zr, and Nb from flotation concentrates or acid bake residues. This is accomplished by cracking the zircon and fergusonite minerals with caustic soda at high temperatures, followed by water washing to recover excess caustic soda and soluble sodium silicates and phosphates. REEs, Zr, and Nb in the solid residue can then be solubilized with HCl or H2SO4. This paper highlights some of the findings from an extensive laboratory program and discusses several flowsheet implications.

Jan 1, 2014

By Paul J. Axtell

Self-hardening cement-bentontie (c-b) slurry walls were constructed as shear walls to stabilize the downstream slope of Tuttle Creek Dam near Manhattan, Kansas. The slope stabilization was required to protect the existing pressure relief well system located at the downstream toe of the dam. The wells require protection from slope deformation induced by liquefaction of the foundation sands during or immediately after the design seismic event. The shear walls are transverse to the axis of the dam, unreinforced, and relatively brittle members that may be exposed to relatively large shear strains, and possible cracking, during or immediately after shaking. An extensive laboratory investigation was conducted on recovered core samples to optimize the mix design and stabilization scheme. Furthermore, as is the topic of this paper, a portion of the laboratory investigation was to determine the large-strain, or post-peak, shear strength of the c-b material for use in limit-equilibrium slope stability analyses and numerical deformation modeling to assess the magnitude of permanent deformation caused by the design earthquake. These data may be beneficial to other projects that are considering the use of unreinforced c-b slurry walls for seismic retrofit purposes.

Jan 1, 2010

By Christopher C. Jobes, Alan G. Mayton, Timothy J. Matty, Joseph P. DuCarme

Mining injury statistics show that a significant number of back, neck, and head injuries are linked to exposure from vehicle vibration. Use of a suspension seat is a common way to isolate the vehicle operator from the adverse effects of vibration exposure. Thus, researchers at the National Institute for Occupational Safety and Health1 – Pittsburgh Research Laboratory (NIOSH – PRL) performed laboratory studies on four passive and two semi-active seat suspension designs. These are typical of seat suspensions commonly found on large off-road heavy surface mining, construction and agricultural vehicles as either replacement or original equipment manufacturer (OEM) systems. One included a pneumatic (air bladder) spring mechanism. The fifth and sixth suspensions were a NIOSH magnetorheological (MR) semi-active damper design based on the pneumatic (air bladder) and one of the coil spring suspensions above. These suspensions were modified with a commercially available MR damper substituted for the OEM damper. These six seat suspension systems were tested and analyzed, for vertical vibration only, using the ISO 5007 Standard [1]. This paper describes the laboratory vibration tests using a MTS® shaker table and discusses the results obtained for the different suspension designs and highlights the rheonetic technology studied. Implications of the seat suspension designs relative to their capabilities for isolating vehicle operators from vibration exposure are discussed. Results for suspensions 1 through 3 showed frequencies of isolation from 2.1 to 3.0 Hz using the 40-kg (88-lb) mass and from 1.65 Hz to 1.8 Hz using the 80-kg (176-lb) mass. Suspension #4, in tests with only the 80-kg (176-lb) mass, showed an isolation frequency of 3.7 Hz. With the MR damper added to seat suspension #4, the peak transmissibility was lowered from 1.3 to 0.95 and showed a corresponding downward shift in frequency from 2.25 Hz to 1.4 Hz. In fact, the results for suspension #5 (the MR damper added to seat suspension #4), using test #3 conditions of the programmed control algorithm, showed isolation (attenuation of transmitted vibration) throughout the test frequency range from 1.0 to 6.0 Hz.

By Christopher M. St. John, Tony F. Zahrah

Empirical and numerical methods are the two extremes of the tools available for the seismic design of subsurface excavations and underground structures. Both have their limitations: when relying on purely empirical methods directly relevant experience may be scant; site data may be insufficient to justify a comprehensive dynamic analysis. The primary purpose of this paper is to review the analytical tools available to the design engineer of subsurface excavations and underground structures. Particular attention is devoted to simplifed models that appear to be applicable in many practical cases.

Jan 1, 1985

At last year's. annual meeting of The Institute, Sir George Fisher, as President, compared it somewhat nostalgically with a meeting of its kind in the 1920s when comment was expressed on the decline of Australianmining and on the lack of new mineral discoveries.I feel that tonight's annual meeting is even more an occasion for nostalgia, for it represents the seventy-fifth anniversary of the founding of The Australasian Institute of Mining and Metallurgy. I hope, therefore, that I may be allowed to retrace some of the circumstances of this Institute's origin and at the same time to look at some of the broader happenings of those 75 years.From this distance in time it is, of course, much easier to get things in perspective and one of the things that compels enormous admiration in looking back over the history of our Institute is to note the qualities of foresight and keen concern for professional standards which moved the pioneers in this Institute. They had no benefit of hindsight to aid them.Just over 75 years ago, a small group of men met in Broken Hill to discus.s the possibilities of forming an association of mining engineers. The moving spirit was Uriah Dudley, our first secretary, manager of the Umberumberka mine at Silverton. The first formal move to form an association of mining engineers came from the Amalgamated Mining Managers Association of Australasia. At the time, this association was a fairly new group, being 5 years old.It had been formed to try to raise the standard of management throughout the industry. Uriah Dudley and our first provisional president, John Howell, held their first talks in 1891 and further meetings at Broken Hill followed. The inaugural meeting, attended by 200 members, was held in Adelaide in April, 1893.

Jan 1, 1968

By Gloria Fernández

La contaminación por drenaje ácido de mina se considera como la responsabilidad ambiental y económica más grande que actualmente enfrenta la industria minera. En ese sentido, se delimita las áreas afectadas mediante la perforación de pozos de monitoreo a través de un estudio geofísico previo. Por ello, el presente trabajo señala los métodos geofísicos como herramientas que pueden ayudar a delimitar y mapear las zonas afectadas por la contaminación proveniente de drenaje y filtraciones que va desde canchas de relave, pilas de lixiviación a minas abandonadas, etc.

Aug 25, 2002