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By Panfeng Gou

In order to solve the problems of supporting the roof of the gateroads affected by a fault, the movement characteristics of roof strata must be fully understood. In this paper, a plane stress physical simulation model was constructed to study roof strata displacement and deformation of gateroads driven in the hanging wall of the fault after the coals in the footwall were extracted. The results indicated that, due to the effect of fault, vertical cracks, orienting parallel to the dip of the fault, occurred in the horizontal direction of the model within the areas affected by the fault. The roof strata are discontinuous. On the other hand, non-uniform subsidence of roof strata occurred due to the bedding plane separation in the vertical direction. Roof strata, especially the lower roof strata, dip toward the fault. Failure of the surrounding strata is not symmetrical with the roof and floor close to the fault being deformed severely. In the selection of type of supports for the gateroads, the U-shaped steel supports are superior to roof bolting.

Jan 1, 2006

By Klaus Pöllath

The Netherlands RandstadRail project makes use of a large range of sophisticated geotechnical techniques to allow a shield driven tunnel to approach the central station of Rotterdam. This paper describes the construction of three deep excavation pits constructed with 1.2 m and 1.5 m thick diaphragm walls. Besides the presentation of the actual diaphragm wall activities special consideration is given to the break-in and break-out situations of the TBM into the deep excavations pits using sealing blocks and partly glass fibre reinforcement in the diaphragm walls.

Jan 1, 2006

By M R. Stevens, W Mori, G B. Boswell

The Onemana prospect is located on the eastern Coromandel Peninsula, North Island, New Zealand. Systematic exploration involving surface geological mapping, geophysics, rock and soil geochemistry, reverse-circulation and diamond drilling has identified a number of important features of a fossil hydrothermal system at Onemana. This relatively intact gold mineralised system is hosted within a sequence of rhyolitic volcanics and volcaniclastics, overlain by lake sediments, sinters and hydrothermal eruption breccia. The system lies within a graben/half graben bounded by major NE-trending faults which form the approximate boundaries to hydrothermal alteration. Rock and soil geochemistry indicate a broad zone of anomalous gold, silver, arsenic, mercury and antimony. Overlapping elevated rock and soil gold anomalies indicate strongest mineralisation occurs over two zones of hydrothermal brecciation named 'Breccia Knob' and 'Western Ridge'. Geophysical data obtained from Gradient Array Resistivity and Ground Magnetics have been used to produce anomaly maps. The terrain corrected resistivity plot shows a number of well defined linear resistivity anomalies which are believed to represent large silicified and quartz veined bodies at relatively shallow depths. The strongest of these anomalies correspond with 'Breccia Knob' and 'Western Ridge'. Reverse-circulation and diamond drilling targeting these resistivity and geochemical anomalies has confirmed wide intervals of quartz veining, silicification and gold mineralisation. Petrologic data based on drill samples indicates the existence of a laterally extensive gold bearing epithermal system. Hydrothermal alteration is thought to have been caused by strongly convecting, two-phase (boiling), near-neutral chloride fluids which persisted at high temperatures (170 - 220¦C) to the paleosurface. A geological model is postulated of a large, complex, hydrothermal system developed in a shallow lake or marginal lake environment created by rifting and graben development within a recently extinct rhyolitic volcanic centre. Geothermal activity alternated between relatively quiescent periods of unrestricted fluid upflow and sinter development interspersed with violent hydrothermal eruptions caused by near surface silica capping and overpressuring above a major fluid conduit centred under 'Breccia Knob'.  Opportunities for precious metal mineralisation are evident from drilling to date. Upflow of near-neutral chloride fluids to shallow depths favours the presence of strongly mineralised stockworks at relatively shallow depths. Periodic hydrothermal eruptions would have caused fracturing and rapid depressurisation of the hydrothermal system, strongly favouring the precipitation of gold from solution both near surface and within feeder-vein systems at depth.

Jan 1, 1995

By K. Awuah-Offei

An aggregate plant may have difficulty balancing product stockpile inventories if hot mix asphalt (HMA) design engineers do not account for aggregate inventory during mix design. Yet HMA design engineers do not, often, take this into consideration during asphalt mix design. This is due to the lack of tools that enable the lab technician or engineer to optimize the mix for good performance while helping the aggregate plant manage its stockpile inventory levels and reducing the aggregate cost. This work presents a linear programming model of the asphalt mix design problem that helps aggregate plants manage their inventory levels while meeting HMA customer demands. The algorithm is implemented in MATLAB as an Asphalt Mix Design Optimization (AMIDO) program. The program is successfully validated with real-life data. The results show that AMIDO can be used to successfully produce any mix design while reducing the cost of aggregates by using the cheapest stockpile materials. The application of AMIDO will increase aggregate plant profitability when serving HMA customers and could potentially be modified for concrete aggregate customers too.

Jan 1, 2009

By Marlyn King, Kevin Peterson

Power Decks are voids created in the bottom of the borehole through the use of a suspended Super Plug. Explosive energy is started downward at initiation creating high pressures which find relief at the comers of the borehole cylinder in the bottom of the hole. This relief creates a horizontal break to the neighboring boreholes - the same effect as presplitting. This “presplit” represents a change of mass to.the explosive energy,and it is reflected upward in the more efficient form of tensile waves. This provides better use of the explosive energy than compression waves. This technique has created a new way of looking at the ways that explosive energy is transported through the rock mass.

Jan 1, 2002

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By Georgene Renner

With more than 800 booth spaces sold and 540 exhibiting companies displaying their wares, there was something for everyone on the exhibit floor of the 2014 SME Annual Meeting in Salt Lake City, UT Feb. 23-26. The following is a sample of what was offered at the 2014 meeting.

By Peter W. Lipman

In the Rocky Mountain region, variations in Tertiary mineralization correlate with changes in tectonic setting and associated igneous activity that can largely be related to tectonics along the west boundary of the American plate. Successive settings include compressional tectonics and associated continental-arc igneous activity; transitional igneous types associated with intra- and back-arc extension; and basaltic or bimodal basalt-rhyolite assemblages associated with Basin and Range extension in- ward of a growing transform boundary between Pacific and American plates.

Jan 1, 2013

By S Chew, A Bennett, N Di Giorgio, B Osborne

After relining one of two blast furnaces and enlarging its sinter plant in 2009, BlueScope radically restructured its Port Kembla steelworks operation in 2011, shutting a blast furnace and halving its total production. This drastic move in response to unprecedented raw material prices relative to achievable steel prices was like that of many integrated steelmakers worldwide facing similar challenges. The 2011 restructure also saw major changes in the amount and type of iron ores and ferrous burdens purchased, and a fundamental reappraising of ‘value’ in iron ores. This paper outlines the changes to raw materials purchases from 2011 to 2017, how BlueScope has responded to the changes in pricing and raw materials quality, the effect on the sintering and blast furnace processes at Port Kembla resulting from higher gangue content, some of the broad technical and economic challenges faced by steelmakers confronted with lower quality iron ores and how BlueScope is meeting those challenges.CITATION:Di Giorgio, N, Bennett, A, Osborne, B and Chew, S, 2017. Recent Port Kembla experience with iron ore use – sintering and blast furnace, in Proceedings Iron Ore 2017, pp 25–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By David Dardick

Tround International Inc. is developing rock excavation and drilling devices which utilize a simple patented mechanism for firing frangible projectiles. This system launches a salvo of three projectiles with every shot in automatic sequence. Studies conducted by Physics International Inc. have demonstrated that firing projectiles into hard rock such as granite creates fragmentation which is much faster and cheaper than conventional drilling and blasting. The Tround salvo approach enhances this further by a controlled stresswave interaction created by a slight time difference during impact of the individual projectiles. The University of Maryland is conducting additional studies to optimize these parameters.

Jan 1, 1981

New ZealandÆs share of global greenhouse gas emissions, at about one fifth of one per cent, is very small. But the profile of those emissions is unique among OECD countries; more than half come from methane and nitrous oxide associated with livestock agriculture. Consequently, fulfilling its obligations under the Kyoto Protocol is potentially quite onerous for New Zealand.In this paper we use a single region, static general equilibrium model to assess the implications for New Zealand of various climate change policy options. The energy and agriculture sectors are modeled in a detailed manner to enable realistic simulations to be carried out.Choosing an optimal set of policies is made more difficult by the fact that New Zealand relies heavily on emission intensive sectors for much of its export earnings. For example, one emission intensive sector alone, dairy, accounts for over 20 per cent of all merchandise exports. Avoiding carbon leakage is therefore an important consideration in selecting appropriate greenhouse policies.Our analysis shows the degree of sectoral adjustment required is substantial. In addition, the total costs depend on the uncertain level of variables such as the global carbon price and the level of afforestation activities in New Zealand, ie the rate of new forest planting.

Jan 1, 2002

By R. L. Wolfrom, R. Hogg, S. Chander

A gravimetric method for measuring rates of capillary rise in powders was explored. Methods to improve reproducibility and consistency of the results were investigated. In particular, the effects of particle size and packing uniformity were addressed. Studies of the wetting behavior of both spherical glass beads and irregularly shaped synthetic graphite particles by various organic liquids were carried out. Standardized procedures for bed preparation are described. The applicability of the Washburn equation for surface energy evaluation in such systems is discussed.

Jan 1, 2002

By Ren G. Dong, Richard McCormick, Dan E. Welcome

Vibration exposure at workplaces is generally multi-axial. The health effects of vibration exposure also likely depend on the vibration direction. Therefore, there is a wide interest in the simulation of multi-axial vibration in laboratory experiments. Advances in technology have led to the development of a new 3-D test system for studying hand-transmitted vibration exposure and health effects. The purposes of this paper are to introduce the system and to present the results of its preliminary evaluations. Test System As shown in Figure 1, the system is basically composed of three vibration generators, a multi-axis vibration control system, instrumented handle, handle fixture, and shaker-fixture linkages (stingers). [ ] Figure 2 shows the array of three vibration generators (MB Dynamics, Energizer BLACK-500 lbs) and their associated support bases and foundation developed by MB Dynamics (Cleveland, USA), which create the 3-axis simultaneous motion. These electrodynamic exciters are powered by power amplifiers which provide current proportional to the analog drive signal from a controller. The controller (JAGUAR Multi-Input/Multi-Output closed-loop vibration controller) was provided by Spectral Dynamics, San Jose, California, USA). NIOSH-designed instrumented handle was equipped on the system.

Jan 6, 2006

By R. Reed Skaggs, William Gault, Douglas Kooker

Both armored personnel carriers and light combat vehicles are increasingly vulnerable to a variety of highly lethal antitank land mines. As a result, there is a need for modeling and understanding the interaction of mine blast products with respect to the resulting loading and damage mechanisms inflicted by explosive blast and impact on vehicle structures. However, the mechanics of blast soil interactions are still poorly understood. The objective of this investigation is to computationally simulate a series of experimental buried mine explosions in saturated sand soil -- over a wide range of scale – and compare the predictions of blast loading to data. Small scale tests have recently been conducted at the University of Maryland with a few grams of RDX acting against an aluminum plate, while recent full-scale tests at ARL involve several kilograms of TNT against 12,500 kg of RHA. The ARL measurements reported here are based on the Vertical Impulse Measurement Fixture (VIMF) facility, a structural mechanical device that responds to blast loading by measuring the vertical displacement of a fixed mass vertical guide rail, which is a direct measure of the imparted impulse. CTH predictions for vertical momentum of the target plate are within 60 – 80 % of the reported impulse data for this wide ranging set of tests. One of the comparisons, however, suggests that the TNT charge in a particular VIMF test may not have fully reacted.

Jan 1, 2005

By Paul J. Remington

The field data gathered as part of the measurements described in Volumes I and II were re-analyzed in the low frequency regime (.1 Hz to 1 Hz) where motion sickness normally occurs. These data were compared co the international standard ?ISO 2631 Addendum 2: Evaluation of exposure to whole body z-axis vertical vibration in the frequency range 0.1 to 1.0 Hz." For both underground mining machines and surface mining machines the results showed that one would not expect motion sickness to .be a severe problem. New field data were gathered on the vibration reduction performance of various seat designs found on surface coal mining machines. The vibration during normal operation was measured on the seat using the standard seat pad accelerometer package described in the previous two volumes and simultaneously on the floor of the machine at the base of the seat. Preliminary indications are that the so-called high performance seats used for operator vibration reduction do not offer significant improvement over conventional seats.

Jan 1, 1984

By N. J. Wagner, D. G. Modiba

There is currently limited knowledge concerning South African coal deposits as hosts for rare earth elements (REE). This project aims to determine the concentration of REE, including yttrium and scandium (REY+Sc) in various coal seams and adjacent sediments in borehole cores from the Ermelo, Witbank, and Waterberg coalfields in South Africa. Coal petrography (maceral count and vitrinite reflectance), XRD, XRF, sequential chemical extraction procedure (SCEP) before ICPMS, and mineral liberation analysis (MLA) were conducted on the coal and associated sediment samples. The coals were inertinite-rich, medium-rank bituminous coal, with moderate to high ash content. The two dominant minerals in all the coalfields are kaolinite and quartz, except for sample ZBS2M, where dolomite was dominant. The dominant major oxides are Al2O3, SiO2, Fe2O3, and CaO, which concur with the XRD results. The ICP-MS results following SCEP indicated that both coal and the associated sediments were light REY+Sc dominant. There was also an elevation of medium REY+Sc in the Witbank coal’s associated sediment samples. Notably, the samples with the highest REY+Sc results were the sediment samples. The Waterberg samples had the lowest REY+Sc from both the coal (less than 2 μg/g to 7 μg/g) and associated sediments (2 μg/g to 15 μg/g). While the highest REY+Sc was yielded from the Witbank-associated sediments (500 μg/g to 2,500 μg/g). The carbonate fraction step proved to be the most successful leaching step, as most REY+Sc was recovered in that step for all coalfields. In addition to the carbonate fraction, the silicates and sulfide fraction in the Witbank samples, and the ion-exchangeable fraction for the Waterbergassociated sediments samples proved successful in leaching out the REY+Sc. MLA determined that monazite and xenotime in all the coal samples were the REY+Sc-bearing minerals.

Nov 6, 2024

By James R. Kunkel

The paper point out the use about of robust water-balance method for sizing heap leach solution ponds and water reservoirs. In this sense, using a robust water-balance method to size storage ponds and reservoirs as well as to calculate operational water demands is important to assess the interactions between operational and climatological variables for the project.

Sep 13, 2001

By Bruno Bussière

Le drainage minier acide (DMA) provenant de la circulation des eaux à travers les rejets miniers sulfureux est sans doute le principal problème environnemental auquel est confrontée l?industrie minière. Afin de prévenir les problèmes environnementaux reliés au DMA, on doit restreindre la présence de l?une et/ou de l?autre des principales composantes menant à la production d?acide, soit l?eau, l?air et les sulfures. Pour ce faire, différentes techniques ont été proposées au cours des dernières années, dont la désulfuration environnementale et les couvertures avec effets de barrière capillaire (CEBC). Dans ce papier, on propose d?utiliser ces deux techniques en combinaison. Ainsi, on produirait un rejet désulfuré à l?usine de traitement qui pourrait, par la suite, être utilisé comme matériau pour la couche de rétention d?eau de la CEBC. Dans un premier temps, on présente les résultats d?une étude de laboratoire qui montre qu?il est possible de désulfurer les rejets de concentrateur à l?aide de la flottation non sélective jusqu?à l?obtention d?un résidu non générateur d?acide. Par la suite, des essais en colonne ont permis de démontrer qu?il est possible de limiter la production de DMA d?un résidu sulfureux à l?aide d?une CEBC dont la couche fine est constituée de résidus désulfurés. Des prédictions théoriques estiment même que la présence de sulfures résiduels dans la fraction désulfurée utilisée comme matériau pour la rétention d?eau peut avoir un effet bénéfique en réduisant la migration d?oxygène. En effet, les sulfures contenus dans la couche de rétention d?eau peuvent consommer l?oxygène qui tente de migrer vers le bas et, ainsi, réduire les flux d?oxygène qui atteignent les rejets réactifs.

Nov 1, 2002

By John Freer

On 25th November, 1983, nearly forty members of The South African Institute of Mining and Metallurgy, together with Doris Gardner and Judith Money from Kelvin House, travelled by luxury motor coach to Secunda, there to visit the coal-mining and conversion operations of Sasol Limited.

Jan 1, 1984

The application of biogeochemical methods in mineral exploration in semi-arid to arid environments in Western Australia has been investigated in an area near Norseman.The study involved a comparison of trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB prospect, where nickel-iron sulphide mineralization occurs in a "greenstone" sequence of ultrabasic, basic and sedimentary rocks.Analyses of unweathered and partly weathered rock from diamond drill cores show the ultrabasic rock to be highly variable with respect to Ni, Cu, Co, Zn and Mn.Samples of weathered bedrock and overlying soil were analysed for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared with approximately 15 per cent in the weathered ultrabasic rock.The soil has a sufficient residual content to provide a reliable indication of the chemistry of the underlying rock. Total trace element analyses of the -89 mesh fraction show strong anomalies for nickel and copper over the mineralized zone. Important amounts of nickel, cobalt and, to a lesser extent, copper are apparently associated with secondary iron and manganese oxides in the soil.Melaleuca sheathiana (tea tree) has been used to study the relationship between soil and plant chemistry. No strong relationship between plant and rock type was observed. Analyses were made of leaves, twigs, wood, bark and roots, and all plant organs were found to have anomalous nickel and copper contents near the mineralized zone. Leaves were found to give the best contrast in the anomalous area and to show fewer erratic values than other organs. It is concluded that the uptake of trace elements by tea tree is low in the semi-arid to arid environment of Western Australia, but that analyses of the plants do reflect the presence of mineralization.

Jan 1, 1973