Search Documents

By Y. Hwang, C Kang

To understand the effect of thermal loading from HLW on the groundwater flow nearby, the coupling of TH in an equivalent porous medium is studied. Results indicate that under given conditions the alteration of groundwater flow by decay heat is localized phenomena. More comprehensive studies are underway for THM coupling. Zum Verstandnis fur die Wirkung der thermischen Belastung von HLW in der Nahe von Grundwasserstrom, ist die Verbindung von TH in den entsprechenden porigen Medium erarbeitet. Die Ergebnisse zeigen, dass unter vorgegebenen Bedingungen die Anderung von Grundwasserstrom durch Zerfallwarme lokalisiert wird. Zusatzliche umfassende Arbeiten sind fur die THM Kupplung auf dem Wege. Pour comprendre l'effet du chargement thermique de HLW sur l'écoulement d'eaux souterraines tout près, l'accouplement du TH dans un milieu poreux équivalent est étudié. Les résultats indiquent que dans des conditions données le changement d'écoulement d'eaux souterraines par la chaleur d'affaiblissement est des phénomènes localisés. Des études plus complètes sont en cours pour l'accouplement de THM.

Jan 1, 2003

By Lees M. G, Vitnell B. W

The post-war need to increase coal production promoted an intensive drilling campaign. Ineffectiveness in core recovery inclined the coal industry towards percussion drilling rather than diamond drilling. The Joint Coal Board, recognising the greater potential of core drilling, has actively encouraged improvement in techniques and equipment. One outstanding need was a barrel which, over and above other improvements being achieved, would permit recovered core to be examined before it had been subjected to the increased fragmentation and displacement which to date has been inevitable except in core which has been drilled in solid sticks û as New South Wales coal rarely can be drilled. In conjunction with Triefus Pty Ltd a barrel with a split inner tube has now been evolved, as a result of which, core can be more accurately logged, division in to lengths for analysis more aptly made, any core loss more reasonably allocated to appropriate plies, and a greater percentage of core recovered û of the order 95 per cent and more. The one half of the split inner tube is lifted from the other and the logging completed before the core is disturbed.

Jan 1, 1957

By Jarrod Bonsmann, Zachary T. Plitt

"A surge in mine related deaths in Middle Eastern conflicts over the past few years has prompted research into the mitigation of the impact on a blast loaded vehicle. In past military conflicts, it has been observed that blast loading can cause injury to the brain but the exact cause is unknown [1]. The recent rise in deaths due to Improvised Explosive Devices (IEDs) has led to research that has speculated that the high acceleration experienced by soldiers on a blast loaded vehicle leads to Traumatic Brain Injury (TBI) [2]. This research aims to investigate vehicle designs that can reducethe peak acceleration for passengers on board the vehicle, in the event that the vehicle is blast loaded by an IED."

Jan 1, 2016

By G. W. Harris, J. J. K. Daemen

Slightly shorter, modified version also published in CIM Bull., vol.94, no.1047, Feb. 2001, p.52-55. To minimise ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will allow more accurate location of the grade boundaries on the surface of a blasted rock pile before excavation. A method has been developed and tested for measuring accurately the direction and magnitude of subsurface blast movement, using a caesium vapour gradiometer and a real-time, differentially corrected global positioning system to locate the pre- and post-blast positions of magnetically enhanced target objects placed in blastholes inside a bench. The procedure does not necessitate disturbance of the blasted rock and the movement information is available sufficiently quickly to allow for modification of the selective mining boundaries for each surveyed blast. It was found that the maximum depth of target detection was 18 m and the overall accuracy was plus or minus 1 m horizontally and 1.2 m vertically

Jun 21, 1905

By K. Burke, G. Zhan, A. Mayer

A cover with capillary barrier effects (CCBE) is being constructed on the AA Leach Pad at the Barrick Goldstrike Mine site near Carlin, Nevada. The purpose of the cover is to eliminate/minimize infiltration of meteoric waters into the leach pad. Laboratory and numerical analyses indicate that Carlin Formation siltstone (TCS), a locally available material, has the necessary hydrologic characteristics when placed on the leach pad to act as a CCBE. A pilot study has been conducted on a small-scale test cover placed on the AA Leach Pad to examine the cover performance under irrigated conditions. The preliminary test results demonstrate that the designed cover is capable of preventing meteoric water infiltration.

Jan 1, 2001

By André C. Zingano

The coal pillars in room-and-pillar mining method are subjected to vertical stress due to overburden rock mass and horizontal stress relieve due to entries excavation around them. Some coal mining companies are applying rock bolts and steel straps to improve the pillar strength, consequently to reducing the pillar size and increasing coal recovery. This kind of approach deserves some discussion, whether it is pillar reinforcement or just rib support. The efficiency of pillar reinforcement (or rib support) is directly related to the initial load capacity of coal pillar, the type of excavation, and the width to high ratio of the pillar. The objective of this paper is to understand the mechanism of pillar reinforcement (or rib support) using rock bolts and steel straps on pillar ribs. Numerical simulation taking into account the relations listed above. The results showed that the increase of coal pillar strength is very short, and there is no influence on improvement of load capacity of pillar. However, the rib support avoids block falling, rib failure, and displacement, reducing the pillar failure propagation into the pillar center. Keywords: coal, pillar reinforcement, room and pillar.

Jan 1, 2006

By Northcutt Ely

This volume- summarizes mining and petroleum legislation in 18 European jurisdictions. Within these jurisdictions, primary attention is given to requirements that must be met in each country for acquisition of rights to permit development of mineral resources. Coverage includes: First, identitication of the controlling laws or statutes governing minerals acquisition and reference to the administrative authority; second, analysis; of the laws governing mines and quarries and their products; third, analysis of laws applicable to natural gas, petroleum, and related materials; and fourth, mention of laws regulating offshore operations. Where pertinent, sections dealing with historical background or administration have been added in countries where minerals are subject to control of States or Provinces, those areas are considered separately from the central government.

Jan 1, 1974

By S. Thorley

In engineering design of operator?s compartments, in underground mining equipment, ergonomics principles are often neglected or not given the full recognition they deserve. This paper defines ergonomics, applies it to machinery in an underground mining environment and describes the ergonomics analysis undertaken during the design phase of an EJC extra-low-profile mining loader. Encompassing the design of the operator?s compartment of this new loader, this paper illustrates the importance of ergonomics principles within the collective design process, ensuring that it is fully integrated into the design approach. An ultimate aim of this study is to ensure that all future designs follow this route to guarantee not only the outcome of a highly efficient, cost-effective and productive machine but that it is also takes the human factor into account, not only in maintenance but also in operation. Maximizing comfort will have the ultimate outcome of actually increasing productivity.

Jan 1, 2006

By C. W. Owings

"Coal may be and has been hauled safely at approximately the same cost with permissible2 storage-battery locomotives as with trolley, cable-reel, crab-reel, or nonpermissible storage-battery locomotives. While in general, thinking mining men readily admit the relative safety of the permissible storage-battery locomotive there are some persons who question the safety of this type; however, the greatest opposition to the widespread use of storage-battery locomotives is from those who believe them to be more expensive to operate and to be more expensive in first cost than the trolley or cable-reel locomotive. Data collected during a comprehensive study- of storage-battery and wired transmission of power in some Pennsylvania and West Virginia coal mines indicate that there is but little difference between the cost of hauling with cable-reel or with storage-battery locomotives. It would appear that if this fact were mere generally known mine operators of the more progressive type would install such equipment and avail themselves of greater safety in hauling coal.The need for greater safety in haulage in coal mines is readily understood when it is considered that during the 12 month period, July 1, 1929 to June 30, 1930, trolley or cable reel gathering locomotives caused four explosions in which 407 lives were endangered, 11 persons were injured, and 30 lives were lost. Still another disaster was averted by the vigilance of a fire boss, who discovered a stratum of gas 3 feet thick at the top of an entry into which a gathering locomotive was about to enter. Other explosions not resulting in any fatality probably have not been reported. In addition numerous fires have been caused by trolley or cable-reel locomotives, and these fires probably would have been avoided had permissible storage-battery locomotives been used."

Nov 1, 1930

By D. W. Levinson, L. E. Tanner

DURING the course of an investigation of the zirconium-iron-tin system the zirconium-iron system was reexamined up to 55 pct* Fe. The alloys pre- visible melting3 and X-ray diffraction studies were made of samples of the alloys. The ferromagnetic properties of ZrFe2were determined by Professor P. W. Selwood* using a modified Faraday balance.4 The zirconium-rich portion of the phase diagram is presented in Fig. 1 and compared with the work of Hayes et al.1 The maximum solubility of iron in ß is somewhat decreased while the eutectic temperature is raised. There seemed to be no change in the eutectic composition of 16 pct Fe. Since the base material was so low in iron content, it was possible to establish the maximum solubility in a between 0.017 and 0.025 pct Fe at the eutectoid temperature. The observation of fine ZrFe, particles in the micro structure of a specimen of 0.012 pct Fe alloy quenched from 700°C indicated that the solubility drops below this composition at 700° C and lower. Further study was made of the intermediate phase ZrFe2. wallbaum5 identified the compound initially as ZrFe2 with a C 15 (MgCu2) structure, placing it at 55 pct Fe stoichiometrically. Hayes et al.1 believed they found the phase at about 47.2 pct Fe and called it Zr2Fe3 but reverted to ZrFe, in the discussion of their paper.6 Jordan and Duwez7 confirmed Wallbaum's work as well as finding the same single-phase structure to about 62.3 pct Fe or Zr0-61 Fe2-18. In order to establish the ternary phase relations in the zirconium-iron-tin systema the exact position of this phase had to be known. This was accomplished by X-ray diffraction, visible melting, and metallographic techniques. Elliott8 obtained a single-phase ZrFe2 X-ray diffraction pattern from an alloy of about 55 pct Fe. This was confirmed in the present study with an alloy of 54.81 pct Fe. However, extra lines (attributable to a or ß zirconium) were found in diffraction patterns of the 47.42 and 49.83 pct Fe alloys. The melting characteristics of these same alloys were studied by suspending 47.42, 49.83, and 54.81 pct

Jan 1, 1960

By K. Nong, H. F. Fuls

The quality of Pregnant Leach Solution (PLS) at Skorpion Zinc is of utmost importance for efficient operation of the Solvent Extraction (SX) Plant. Suspended solids in the PLS forms CRUD in the settlers, resulting in reduced zinc transfer capacity and increased impurity carry over to Electrowinning. The Ishigaki Fibre-Wakishimizu filter (fibre media rapid filtration equipment) has been identified as polishing filter that potentially could remove solids from the PLS of Skorpion Zinc. A pilot unit with 20m³/h capacity was tested on site over a period of 9 months under plant operating conditions in the refinery. The FW filter produces a clear filtrate, acceptable for the Solvent Extraction. Turbidity is improved by 72%. Gravimetric analysis indicates a 47% removal of solids. However, the gravimetric method is biased by a co-precipitation of saturated salts during the analysis. Filter media is blinded by the Skorpion Zinc PLS solution, as result of suspended solids and process chemistry. The media could not be regenerated to acceptable conditions. Further testwork to investigate the impact of process solution chemistry modification on blinding is undertaken. Based on the outcome of this investigation a final decision on the FW filter can be taken.

Jan 1, 2007

By J. de Villiers

Through the application of the Rietveld method, X-ray diffraction analysis has developed into a fully quantitative method for phase analysis. The Rietveld method itself has progressed from an unstable method that required constant operator intervention to a stable and robust method suited even for routine analysis. The method, however, requires a good initial calibration and periodic checks on its precision and accuracy. Several examples from minerals processing, pyrometallurgy, and materials science show the strengths and applicability of the method. The limitations and sources of error are also discussed.

Jan 1, 2007

The steps for the beneficiation of iron ores differ from ore to ore, depending on the mineralogical phases of the particular iron ore and the nature of the association of the gangue minerals with iron oxide in that ore. The extent to which the beneficiation can be undertaken economically depends both on the amount and the nature of the gangue. The analysis of the phases present in an orebody optimises the mining and process operations (separation, beneficiation, sintering, etc).X-ray diffraction (XRD) provides qualitative and quantitative information about the main ore phases as well as the gangue mineralogy and the amorphous content present in a sample. In addition, modern quantification methods such as Rietveld refinement allow the calculation of the distribution of elements in solid solutions such the substitution of Fe with Al in goethite or hematite.The use of high speed detectors has made XRD an important tool for grade and process control. Finger printing of XRD data can facilitate multi-dimensional mapping of ore deposits and drill cores, identifying regions of favourable mineral compositions. Grade control using XRD can be completely automated and controlled remotely.The two case studies in this paper demonstrate how XRD and finger printing can be used for grade control, process optimisation and quality control of a goethitic and a magnetitic iron ore. The enormous potential of XRD as an inexpensive, reliable tool, useful in the characterisation of iron ores will be demonstrated.CITATION:K÷nig, U, 2013. Application of x-ray diffraction to iron ores - potential implications for grade control and downstream processing, in Proceedings Iron Ore 2013 , pp 275-280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

NIM reports Report No. 1615 Fluorspar pellets. A survey of the world market and an assessment of future South African production. Report No. 1621 Correction for matrix effects in the analysis of solutions by X-ray-fiuorescence spectrometry. Notices Questionnaire on Technicians The Department of National Education's committee of enquiry into the education, training, utilization, and status of engineering technicians in the Republic of South Africa was established as a result of Resolution 6.3 taken at the Sixth Conference on Engineering Education: The Education and Training of Engineering Technicians. Vraelys oor Tegnici Die Departement van Nasionale Opvoeding se komitee wat ondersoek instel na die opleiding, gebruik en status van ingenieurstegnici in die Republiek van Suid-Afrika is gestig as gevolg van Besluit 6.3 wat geneem is tydens die Sesde Konferensie oor Ingenieursopleiding: Die Opleiding van Ingenieurstegnici. Competition for Student Members of the South African Institute of Mining and Metallurgy Each year the Institute offers a prize (or prizes should the entries warrant it) of up to R100 for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute.

Jan 8, 1974

By P. Trueman

A project is underway to convert a validated methodology to a system that will permit the near real time interpretation of loading data from longwall powered supports, allowing rapid adaptation of mining strategies, maintenance scheduling and set pressures for optimal roof control. Such a system has the potential to significantly reduce roof control problems and is a pre-requisite to successfully fully automating a longwall face. The development depended upon a robust methodology for interpreting the pressure sensor data coming from the face in the context of support strata interaction using a novel characteristic load cycle analysis concept. New software was developed capable of handling the large quantity of data emanating from a modern longwall with the current level of signal corruption and loss, accurately delineating load cycles and extracting the critical load cycle features essential for interpreting how the support and strata are interacting. Existing software being used to access the pressure data were found either to be incapable of delineating load cycles at all or, where they could, the accuracy was low, making it impractical to use them in combination with the new advances in load cycle analysis. The software is currently being extended from ?off line? to ?on line? in order to provide a real time response to changing strata conditions.

Jan 1, 2006

By William W. Aljoe

The hydrologic characteristics of two abandoned underground coal mine sites, near Latrobe, PA, and Uniontown, PA, were investigated by the U.S. Bureau of Mines for possible implementation of alkaline injection into the mine pools as a means of abating their acid discharges. The Latrobe site was chosen for a one-time application of alkaline injection to achieve a partial, short-term neutralization of a limited portion of the mine pool. A quantity of alkaline reagent (sodium hydroxide) sufficient for a one-time neutralization of the water in this portion of the pool was added. Although nearly all of the neutralizing reagent had moved away from the injection wells within 6 weeks, no evidence of neutralization was noted at the mine discharge during the study period. This lack of neutralization probably occurred because the injection wells did not intercept a primary flow path through the mine. Criteria for successful application of alkaline injection at this or other sites include (1) positive identification of the primary flow paths through the mine pool and (2) addition of quantities of alkaline reagent sufficient to neutralize the entire volume of the pool along the primary flow path.

Jan 1, 2010

By Andre Zingano

The variation in pillar behavior at underground coal mines working in the Bonito coal seam is observed in both research and mining company case studies. There is no consistency in pillar behavior, as it varies from mine to mine. In some cases, it is possible to find rib yields for both excavation modes and pillar sizes. This paper?s objective is to investigate pillar behavior for different load conditions and pillar sizes. Three-dimensional numerical simulation models considering these factors were built. A matrix was then assembled to compare pillar behavior between loading conditions, as well as between different pillar sizes with the same loading condition. The results showed some pillar rib plasticity due to vertical loading and stress relief independent of the pillar size and load. For the same load conditions, the yielding thickness is the same for different pillar sizes.

Jan 1, 2012

By A. Patri, D. S. Nimaje

Wireless sensor networks and wireless communication systems have become indispensable in underground mines. Wireless sensor networks are being used for better real-time data acquisition from ground monitoring devices, gas sensors, and mining equipment, whereas wireless communication systems are needed for locating and communicating with workers. Conventional methods like wireline communication have proved to be ineffective in the event of mine hazards such as roof falls, fires etc. Before implementation of any wireless system, the variable path loss indices for different workplaces should be determined. This helps in better signal reception and sensor node localization, and also improves the method by which miners carrying the wireless devices are tracked. This paper proposes a novel method for determining the parameters of a suitable radio propagation model, which is illustrated with the results of a practical experiment carried out in an underground coal mine in southern India. The path loss indices, along with other essential parameters for accurate localization, have been determined using the XBee modules and ZigBee protocol at 2.4 GHz frequency.

Jan 1, 2015

By Karl A. H iggins, James P. Racine

"Displacement Cast-in-Place (DCIP) piles are not a common deep foundation type in the Washington, DC Metro Area market. As a result, less regional data is available for these foundations compared to other alternate deep foundation types. Displacement cast-in-place piles (DCIP) differ from traditional Auger Cast-In-Place (ACIP) piles in that the pile annulus is formed by pushing a partially-flighted, auger bit to depth via a large mandrel. The auger bit includes a displacing body near the bottom of the tooling. Therefore, little to no spoils are generated during installation and the soil around the annulus is largely densified in-place due to the displacing body being slightly larger than the mandrel it is attached to.Due to this densification, one would expect that the theoretical DCIP capacities (compression or tension) would be greater than an ACIP pile (assuming a pile of similar length and diameter). After 20 static load tests and the installation of over 6,000+ piles on the MGM National Harbor Casino Project, the differences in pile support characteristics between DCIP and ACIP piles of same size and depth was small. The performance of both pile types depended on the density and type of soil within the bearing stratum. In some early cases of DCIP use, the performance exceeded expectations and appeared to be more in line (or better) than typical capacities obtained from driven displacement piles. Other times, the tip elevations could not be achieved or were so difficult to achieve that installation delays occurred and/or significant additional engineering effort was required to address piles short of their requirement embedment.This paper will discuss the limitations of DCIP pile installation in dense Coastal Plain soils and will present the lessons learned during this project. The paper will also compare the DCIP pile type to both conventional ACIP and driven displacement piles utilizing regional and site-specific load test and installation data."

Jan 1, 2017

By Martin Hertzberg

This Bureau of Mines report analyzes diverse observations of the rates and mechanisms for the pyrolysis and devolatilization of coal and polymethylmethacrylate (PMMA). New data are presented for PMMA, together with new morphological evidence for the microscopic structure of the pyrolysis and devolatilization wave front in coals. It is concluded that there is no substantive evidence to support the traditional viewpoint that the pyrolysis and devolatilization rate process occurs isothermally, under chemical rate control; or is described realistically by a classical, unimolecular Arrhenius function of temperature. Instead, the reaction process occurs as a highly nonisothermal, heat-flux-driven, pyrolysis and devolatilization wave front, whose speed of propagation is predictable by internal heat transport constraints. Except for the complication of its charlayer residue, whose increasing thickness insulates the pyrolysis wave front from the heat source flux that drives it, both coal and PMMA behave similarly during pyrolysis and devolatilization. For PMMA, decomposition occurs at a temperature of 3500 to 5500 C; for coal it occurs at 4500 to 6000 C. There is no evidence that the reactant temperature ever exceeds those values regardless of the source temperature to which the samples are exposed.

Jan 1, 1988