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By Anthony Iannacchione, Christopher Mark

Residents of Maxwell Hill, a suburb of Beckley, West Virginia, reported from January until March of 1988 a series of earth tremors. The tremors rattled dishes, and the noises associated with tremors were sometimes loud enough to wake people at night. These events were puzzling because Beckley is in an area of low seismic activity. Maxwell Hill is located above abandoned coal mines, though no direct subsidence damage to surface structures has been documented. A research program was initiated to determine whether subsurface ground movements associated with the abandoned mines could be responsible for the seismic activity experienced at the surface. A hypothesis is proposed which states that seismic disturbances can be caused by abandoned mine failure when two conditions are met. First, some instability must exist at the mine level. The most likely cause of instability is the failure of pillars of coal that were left for support at the time of mining. Second, subsurface movements can result in significant seismic activity only when the rock above the mine contains at least one very strong and brittle layer that is prone to fail violently through rupture or fault slip movement. Analysis of the data indicates that both hypothesized conditions for mine-related seismicity appear to have been satisfied in the case of Maxwell Hill. It has therefore been concluded that the earth tremors experienced by Maxwell Hill residents probably are related to the abandoned mines. Analysis of the potential magnitude of these events indicates that they are unlikely to cause significant surface danlage. The probability that future events will disturb the residence of Maxwell Hill should be quite low based on the identified mechanism.

Due to the reduction in frictional resistance, the characteristics of joint infill have a major role to play on rock mass instability. This paper elucidates the laboratory behaviour of graphite infilled joints based on a large-scale shear apparatus under constant normal stiffness (CNS). Discontinuities in a graphite mine have been simulated using high strength gypsum plaster, with the joints infilled with compressed graphite layers. The Fourier series was employed to characterize the joint surface, and the method of using the Fourier coefficients for the prediction of dilation and normal stress with displacement is explained. Die Charateristik von Verbindungsfüllungen hat einen wichtigen Einfluss auf Felsmassenstabilität aufgrund der Verringerung des Reibwiderstandes. Diese Veröffentlichung untersucht das Verhalten von Graphit gefüllten Verbindungen im Labormaßstab mit einer Methode die auf einem gross-umfang Apparateprinzip unter konstanter Normal-Steifheit beruht. Unregelmässigkeiten in einer Graphit Mine wurden mit Gypsum Gips von hoher Festigkeit simuliert, die Verbindungen wurden mit kompressierten Graphitschichten gefüllt. Fourier Reihen wurden angewandt um die Verbindungs Fläche zu Characterisieren. Die Methode die verwendet wurde um die Ausdehnung und Normalkraft mit der Verschiebung mit Hilfe von Fourierkoeffizienten zu bestimmen wird beschrieben. Due à diminution des résistances par frottements, les caractéristiques des joints de remplissage joue un rôle majeur sur les instabilités de la roche. Cet article étudie le comportement en laboratoire des joints de remplissage en graphite à partir d’un dispositif de friction à grande échelle sous rigidité normale constante. Les discontinuités dans une mine de graphite ont été simulées grâce à un plâtre à haute teneur en gypse, dont les joints ont été remplis de couches de graphite compressées. La caractérisation de la surface des joints a été réalisée avec les séries de Fourier. La méthode utilisant le coefficient de Fourrier pour la prédiction de la dilatation et de la compression en fonction du déplacement est également expliquée.

Jan 1, 2003

By K Watanabe

A relational database in which its complex contents can be navigated through a map interface (ie spatially enabling) is relatively a new concept yet attractive for geoscience fields. This concept is made possible using the new breed of geographic information system (GIS) that utilises component object model and relational database management system. Such sophisticated yet open and highly interoperable platform makes possible the integration of data management, analysis, and modeling processes into single workflow. Taking benefit of this technology trend, several initiatives emerge in geoscience to establish digital data models, such as the petroleum industry, the North America digital geologic map data model, and the ESRI geology data model. The mining industry unfortunately has not followed same paths due to the lack of data model and standards in its history. This paper presents an effort on establishing a digital data model for mining-related geoscience databases. The aim is to promote several standards by proposing a preliminary data model and demonstrating that the model is working for the mining business datasets. The case study is the island of Java, the western part of the Sunda island arc of Indonesia. Many types of datasets, such as geologic maps, topography, mineral deposits, structures, geochemical and geophysical data were dealt with and were transformed relational geologic databases of Java using the new Geodatabase geographic data model. Intelligent GIS tools were investigated for geologic applications, ranging from generic to specific purposes. Subtypes and domain were used to set up constraints, while topology rules and relationship classes were used to create links among data layers. The linear referencing system was used to model drillhole data. The current results show that the generic GIS and relational database can handle typical tasks related with mining business datasets. A preliminary data model is finally suggested.

Jan 1, 2004

By G. Velarde

This paper presents the metallurgical results of column and stockpile leach tests with forced aeration to determine the usefulness of this process in the operational leaching at Sociedad Minera Cerro Verde S.A.A. The evolution of the aeration system is presented and also an innovative solution developed to overcome forced aeration’s main problem, which is the early obstruction of the aeration pipes located at the base of the stockpile, causing a decrease in air and oxygen levels and therefore a reduction in the metallurgical benefits.

Jan 1, 2006

By James K. Richardson

STATISTICAL evidence shows that continued efforts made by Government and industry to make mining safer during the last two decades have had most favorable results. In the copper-mining industry an accident frequency of 146 per million man-hours worked in 1925 dropped 71 per cent by 1945 to 43. This downward trend was relatively consistent except for a high period in 1937 which was probably due to a resumption of large-scale operation with many untrained miners. The iron-mining industry showed a similar trend, but at the relatively lower accident frequency of 66, which dropped to 24 in 1945. The close relationship between the steel and iron-mining industries may be one reason for the lower accident frequencies, because the steel industry is noted for its greater recognition of the fact that safe working conditions are an important part of labor-management relations.

Jan 1, 1948

By Simon Strong, Tim Brown, Luis Ignacio Sanz Vivanco

"One of the most significant technical and practical challenges facing the tunnel construction team on the Legacy Way road tunnel project in Brisbane, Australia was how to erect the pre-stressed precast concrete slabs to form the smoke duct in the tunnel boring machine (TBM) tunnels. An essential part of the tunnel ventilation system, the smoke duct, extends the full length of the 4.6km long twin, two lane tunnels. The vast majority of the tunnels (approx. 4.3km) were constructed using two 12.4m diameter double shield TBMs. The refurbished Herrenknecht machines broke several world records on the way to completing the tunnel excavation works in just over nine months. With the excavation complete the focus turned to solving the complex civil tunnel fit out challenges. A key component of the civil fit out of the tunnels was constructing the smoke duct in the TBM tunnels which was designed as a precast solution. The slabs which each measure 8.62m long by 2.0m wide by 200mm thick and weigh close to 9 tonne need to be erected above cast in situ corbels whilst other tunnel finishing works continue. The space proofing clearance offered by the design to the support corbels below and the precast segmental lining above was in the order of only 100mm. This paper details the events of how the Transcity JV tunnel fit out team, comprising some of Europe and Australia’s leading tunnel construction specialists, drew upon the global strengths of the existing JV member companies and the global reach of leading TBM manufacturer Herrenknecht to develop an innovative system to solve this challenging problem. This globetrotting story, which starts in Australia, visits Europe and mainland China before returning to Brisbane where it all began."

Jan 1, 2016

By Steve Kral

President Bush’s National Energy Program and his Clear Skies Initiative both emphasize the use of coal to help meet the nation’s growing energy needs. And why not? Coal is currently responsible for more than 50 percent of the nation’s electricity generation. That fact, though, seems to be lost on policy makers, the environmental community and the public. Critics of coal advocate the increased use of renewable energy sources and the increased use of natural gas. Renewables, though, are only capable of generating a tiny fraction of the power required. Natural gas is expensive. And natural gas production cannot keep up with demand, especially given the nation’s increasing energy needs.

Jan 1, 2003

By S. R. Droes

The U.S. Bureau of Mines investigated calcium fluoride (CaF2) assisted sulfuric acid (H2S04) leaching as an alternative to the melting-quenching procedure to obtain Mn from domestic manganese silicate resources. Pyroxmangite [(Mn, Fe) Si03] ore containing, in percent, 34.4 Mn, 22.8 Si, 2.6 Ca, and 1.3 Fe was leached in a 500-mL resin kettle. Ninety-six percent of the Mn was extracted under conditions of 330 g/L ore, 245 g/L H2S04, 35 g/L CaF2, 90' C, and 2 h. To incorporate electrowinning in recovering Mn, the ore was leached with a simulated spent anolyte solution containing, in grams per liter, 12 Mn, 140 H2S04, 130 (NH4)2S04 (ammonium sulfate), and 5 CaF2. Manganese extraction of 92 pct was achieved from 130 giL ore leached at 90° C in 3 h. The Fe, silica (SiOJ, and other impurities were precipitated from the pregnant solution by neutralization with ammonia (NH3). Manganese of greater than 99-pct purity was deposited at a cathode current density of 50 mA/ cm2 at 30° C, with a current efficiency of 65 pet in a two-compartment cell. A flowsheet was proposed for the leaching and electrowinning procedure.

Jan 1, 1990

By HILAND BATCHELLER

COMMENT on the economic significance of the special alloy steels seems inevitably to reduce itself to an attempt to peer into the future of the industry in which we are interested. We are all familiar with the historical development of iron and with the almost complete replacement of iron by steel. Those who have been connected with the industry since its .early days have had the satisfaction of witnessing the greatest industrial development the world has seen. As the cartoonists of the muck-raking decade liked to picture steel as an ogre armed with a spiked club, his hands reeking with blood and with golden coins dripping from his pocket, fiercely seeking for more widows and orphans to devour, I choose to call on my imagination to create a gigantic but beneficent robot of such marvellous mechanical skill. that it quickly transforms millions of tons of otherwise worthless material into the infinite variety of useful products which are so largely responsible for our present civilization.

Jan 1, 1931

By William D. Spielvogel

The Massachusetts Highway Department awarded the Porter Street Outfall Project to the J.M. Cashman Company in November 1991. Timely completion of the Project in one and one half years is critical to the start of the subsequent Third Harbor Tunnel North Approach project. Existing subsurface conditions and the Project's location at Boston's Logan International Airport significantly increases the difficulty of construction. The major contractual work involves relocating a reinforced concrete double box culvert supported on a continuous wood pile foundation. This existing culvert crosses and interferes with the future Third Harbor Tunnel North Approach alignment. Two parallel culverts constructed approximately 20 feet from either side of the future Third Harbor Tunnel alignment replace the existing double box culvert structure. Under the original contract design, approximately 3,100 feet of 14 ft. by 15 ft. reinforced concrete culvert is cast in place adjacent to the west side of the Third Harbor Tunnel and is located in the center of the Airport's main service roadway, Harborside Drive. This culvert is the Porter Street Combined Sewer, PSCS, which handles a combined flow of sewerage from the East Boston community and storm water runoff from Logan Airport. In addition, approximately 2,230 feet of 17 ft. by 15 ft. reinforced concrete culvert is cast in place adjacent to the east side of the Third Harbor Tunnel and is within 20 feet of an active aircraft taxiway and heliport. This culvert is the Bird Island Flats Storm Drain, BIFSD, which handles storm water runoff from the Logan Airport airfield. The existing outfall, on the west side of the Third Harbor Tunnel alignment is to remain in service and is to be connected to the new PSCS and BIFSD culverts. Therefore, a portion of the BIFSD culvert is designed as a bridge to span 128 ft. across the Third Harbor Tunnel excavation during construction.

Jan 1, 1994

By J Webster-Brown

The Tui Mine is an abandoned Pb-Zn mine giving rise to water quality problems in the Te Aroha region of Coromandel, New Zealand. When sampled in September 2002, for example, both the Tui and Tunakohoia Streams draining the mine site exceeded ANZECC (2000) water quality guidelines for aquatic life protection (Cu, Cd and Zn) and recreational quality (Cd). Based on trace metal mass flux (kg/yr) from parts of the mine site, the principal pathways by which Cu, Zn and Cd contamination reach these streams have been identified as:the tailings dam leachate,the diverted stream water from above the dam,the drainage from Adit 5 (which accounts for 95 % of Zn and Cd contamination in Tunakohoia Stream), andto a lesser extent, run-off from waste rock piles below Adit 4 level. Of the various remediation options, which have been proposed for the site, the following are identified as providing the best protection for the Tui and Tunakohoia streams:stabilising the tailings dam embankment and capping the embankment and tailings,constructing and/or cleaning out engineered diversion drains around the perimeter of the tailings dam to divert surface water away from the tailings dam, andinstalling bulkheads within Adit 5. A formal postal survey of the people of Te Aroha (66 respondents from 230 surveys) indicated that their priority was that the site be made safe for the public to visit, and used for recreation. As soil samples in potential recreational areas of the mine site, significantly exceeded guideline values for Cu, Pb, Zn, Cd and As, soil removal or capping clearly also needs to be part of a remediation plan. Development of the site as a historical/ecotourism area was viewed favourably, as this may encourage more visitors to the Te Aroha area as well as educate local residents.

Jan 1, 2003

Residual aeolian placers (RAPs) are formed by the wind, by preferential entrainment and removal of small and low-density detritusfrom a pre-existing, typically sedimentary sequence containing heavy minerals. Heavy minerals that are resistant to chemical alteration and either soft and malleable (gold), or extremely hard (diamond, sapphire, ruby, etc), are concentrated as a residual on the wind deflation surface, typically in the interstices between larger resistant clasts. RAPs form preferentially in arid or semi arid areas, where the vegetation is sparse or absent, and where topography and surface gradients are low, but may also form on beaches and in periglacial environments. RAPs consist of a continuous or discontinuous, planar or gently undulating horizon of heavy minerals in a single-clast-thick pavement of resistant pebbles, cobbles, or boulders, which mantles the present topography or palaeo-topography. Extreme wind erosion and surface deflation may condense the full pre-existing sequence into a layer of heavy minerals only. The grade of RAPs is substantially higher than in the precursor deposit, and commonly much higher than those typically found in most other placer types. Aside from their general occurrence as a thin pavement of resistant clasts, the best indicators of residual aeolian gold placers are the presence of wind-eroded stones (ventifacts) on the pavement, and the distinctive and unique shapes of aeolian gold grains themselves. The shape of the gold grains is progressively transformed by sand blasting during placer development, from grains with thickened rims, to toroidal grains on which the rims are æsplitÆ and peened inward toward the grain centre on one or both of the grain sides, to hemispherical or sub-spherical grains that are fully encapsulated by the in-turned rims. Gold that has undergone aeolian shape transformation is difficult to entrain and transport away from the site of aeolian concentration by anything other than mass movement or glacial processes. It is also easily retained by commercial recovery plants of any configuration.

Jan 1, 2004

By Dong-min Lee

As the construction industry is becoming more large-scaled and complex, the BIM technology has been utilized throughout the industry. Since 2008, the construction industry in South Korea (Korea) has required carrying on BIM-based project continually. According to this trend, BIM S/W market, as well as BIM library market is also gradually activated. Many countries have already been establishing Web-based BIM library market, also Korea has been trying to establishing this Web-based BIM library market. In this study, through market research of Web-based BIM library market of advanced countries including the U.S.A. and U.K., establishment strategy of BIM library market to be derived by late starters that introduce BIM such as Korea, Japan and China was deduced based on current establishment status of BIM library market in Korea. In addition, deal with an issue that a clear revenue-sharing system between business principals of Web-based BIM library market is not available at the current stage was presented as a factor of inhibiting activation of BIM library market. So in order to offer a reasonable revenue-sharing strategy in BIM library market as conceptual level, a methodology and process of applying Game theory being used for deriving. It is expected that a reasonable revenue-sharing model between business principals would be presented as its standard of BIM library market to be more activated in the future.

Aug 1, 2013

By P. C. Hodges

WHILE there is very little romance connected with the operation of a stone quarry, yet to those who have participated in the growth and development of a business that has been a pioneer in its field and that FIG. 1.-LOCATION OF PROPERTY OF MARBLE CLIFF QUARRIES COMPANY. has been in continual operation two-thirds of a century there is bound to be a background of experience, which if properly capitalized, brings progress as well as satisfaction in its accomplishment.

Jan 1, 1936

The use of solid state detector and radioisotope x-ray source for x-ray fluorescence analysis is illustrated by analysis for iron, copper, zinc, tin, and lead in about 700 samples taken from Australian mineral process streams. Limits of detection based on counting statistics (3 standard deviations) range from 0·001 to 0·004 per cent by weight element. The analysis accuracy was usualIy between 2 to 10 per cent (rms) of the mean element concentration and was determined by comparison with assays supplied by mineral companies. In most cases the main cause of error appears to be due to this assay and not the x-ray fluorescence technique.Some potential fields of application of solid state detector and radioisotope x-ray source for analyses in the mineral industry are indicated.

Jan 1, 1974

The material presented in this paper describes experimental work to determine the effect of variations in suction nozzle design upon inlet flow conditions. Four entrance profile shapes were examined under controlled conditions of slurry flow and it was found that the straight ended nozzles had consistently higher entrance losses than the straight taper or the ellipse, and that the circular arc profile nozzles were the most efficient. Subordinate considerations were the measurement of the quantities and the forces involved.As the work progressed, three distinct phases in the pattern of flow were apparent and the static pressures in each were carefully examined. An inlet zone was found to be unstable in changing boundary conditions, a transition zone was largely independent of slurry density and in a zone of stability the pressures were found to be directly related to the characteristics of the flowing pulp. In this zone pressure measurements were reproducible within ± 2 per cent regardless of changing boundary conditions.The effect of varying the "1" parameter of nozzles with a part circular entrance profile was examined and it was found that flow conditions approaching the ideal were obtained when the radius of curvature was between 0·40 and 0·550.

Jan 1, 1966

This volume constitutes the Survival Subsystem portion of the final report for the Coal Mine Rescue and Survival System (CMR&SS) program, which was conducted by the Westinghouse Electric Corporation under contract to the United States Bureau of Mines (Contract Number H0101262 dated June 17, 1970). The program was directed by the Special Systems Department of the Westinghouse Baltimore, Maryland, facility. The basic objectives of the CMR&SS program were to develop and test hardware to determine the efficacy of a variety of coal mine rescue and survival concepts and techniques. These concepts were drawn from two major sources: the Request for Proposal from the Bureau of Mines1 and the final report on the Mine Rescue and Survival Study conducted by the National Academy of Engineering2 (NAE).

Jan 1, 1971

Following the experimental work of Denny, Robson, and Irwin, and the clinical investigation by Crombie and Blaisdell, an investigation of aluminium therapy was begun at Washington, Pa., which is situated In a very large industrial section of the State. Some of the men to be studied were from plants manufacturing silica brick, refractories used in steel and glass manufacturing, and semi-porcelain table-ware; others were workers in foundries, sand blasters, and men engaged in the quarrying of ganister rock.This group of workmen gave an opportunity to study the effects of aluminium on various types of silicosis which differed somewhat from that found in hard-rock miners.EXPOSUREIn their occupations, the men studied were exposed to silica dust concentrations ranging from 17 to 97 per cent free silica. In the silica brick industries, the unfired product averages 96 per cent silica in the form of quartz, whereas the fired brick contains 50 to 62 per cent. cristobalite plus 11 to 80 per cent. tridymite, forms of silica that, on account of their higher solubility, are more toxic than quartz. The operational dust counts in the plants varied from 15 to 9,500 particles per c.c., and the median particle size from the aerial samples was 1.0 micron for the green product and 2.0 microns for the fired product. The length of exposure varied with the occupation as well as with the individual plant, but disabling silicosis could be produced in less than four years in certain exposures. The average time needed to produce radiological silicosis in those susceptible to this disease was eight years. Some of the men in our series of cases have been treated as long as fifteen years after exposure had ceased, and have improved under treatment.The dust counts mentioned above had been reduced prior to the aluminium therapy studies and the presen.t exposures do not exceed '900 particles per c.c., the average being 370 particles. per c.c. This improvement in dust conditions was due to improved dust control apparatus, which was installed before aluminium therapy was instituted. Aluminium powder is not a substitute for dust control.PATHOLOGYThe pathological picture of silicosis in men engaged in the ceramic industry is somewhat different from that in hard rock miners." Due to exposure to high concentrations of dust containing high percentages of silica of varying degrees of solubility andvery small particle size, these men are subject to a relatively rapid type of silicosis, which sets up an acute...

Jan 1, 1945

By S Hapugoda, J R. Manuel, M J. Peterson

Microindentation testing using the square–pyramid–shaped Vickers indenter is a well-established technique to determine the microhardness of minerals and materials. However there is a paucity of published microhardness data from Fe ore samples. It is acknowledged that an iron ore’s particle mineralogy and texture is critical to its processing properties, and it is therefore considered that the microhardness of different mineralogical/textural types may also relate to these properties. Mineral microhardness potentially provides inputs to the modelling of breakage characteristics during comminution, as well as the relationship between mineral chemistry and microhardness, and mineral microporosity and microhardness. Microhardness can be determined as single crystal microhardness, for more coarsely microcrystalline samples, or as ‘aggregate microhardness’ for cryptocrystalline or finely microcrystalline samples.Variations in the texture and mineral chemistry of common Fe ore minerals (eg martite and microplaty hematite, ochreous and vitreous goethite etc) are well established and this study provides microhardness data on different textural forms of Fe (oxyhydr)oxides from a variety of different Fe ore deposits. The data indicated that in general, the mineral grain size, microporosity and texture were the main influences on Fe (oxyhydr)oxide microhardness. There were no apparent systematic variations between microhardness and minor element mineral chemistry, with the possible exception of Al content in goethite (for goethites with Al content >0.5 wt per cent), and for goethite total element contents >90 wt per cent (determined by electron probe microanalysis, EPMA). Higher Al concentrations and lower total element concentrations in goethite EPMA analyses correlated with lower goethite microhardness. Microporosity and grain size were more important than texture to hematite microhardness. Different textural forms of dense hematite (eg martite, recrystallised interlocking hematite and specular hematite) with similar grain size exhibited comparable microhardness. Microhardness values for hematite and hydrohematite with little or no evident microporosity were also similar, whereas more porous forms of martite, microplaty hematite or hydrohematite exhibited lower microhardness.CITATION:Peterson, M J, Manuel, J R and Hapugoda, S, 2017. Microhardness testing of hematite-goethite Fe ores – implications for their textural characterisation and geometallurgy, in Proceedings Iron Ore 2017, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Luis Haro

Puesto que el deslizamiento de relaves constituye uno de los principales riesgos para la vida y seguridad de los embalses, se desarrolló un programa que rehabilite los depósitos de los relaves a través de los gaviones y geomallas como elementos que estabilizan los relaves descargados. En este sentido, el uso de geosintéticos revolucionó el diseño de los relaves y sistema productivos y permitió un mejor manejo ambiental de los relaves. Asimismo, la utilización de gaviones como paramento externo en el sistema suelo armado, otorga mayor rigidez al mismo en el caso de paredes, taludes más verticales, drenaje y protección contra la erosión. En consecuencia, el uso de gaviones y geomallas es aplicable para la construcción de depósitos de relave y estabilización de depósitos inactivos.

Sep 13, 2001