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This paper considers the application of recent laboratory gas sorption data to the understanding outburst phenomena in underground coal mining. Previous use of threshold limits based on gas content and coal rank are placed in perspective. Although this work focuses on overseas research and experience, parallels can be drawn for New Zealand coal settings, taking into account localised mining and geological factors.

Jan 1, 1994

By Ö. Erdem

The investment decision making process in the insurance and finance industries is affected by new advances such as simulation techniques. These advances have improved the discounted cash flow method (DCF). In DCF, a dynamic and flexible model construction is not possible because it does not consider uncertain conditions. Each project should be evaluated taking into account the related uncertainties because the related uncertainties determine the characterization of the project. Related uncertainties can be processed in dynamic DCF, which is applicable to both financial and non-financial industries with different kind of uncertainties, such as power generation and petroleum projects. The dynamic DCF method can estimate net present value (NPV) while managing related project uncertainties with a simulation method like Monte Carlo Simulation. The simulation method is preferred because its output is unbiased. Therefore, a more realistic financial evaluation of the project can be concluded. In spite of the improvement of dynamic DCF, this project evaluation method is not used frequently in mining industry. However, the mining industry is ideally suited to this concept because it is highly dependent on estimations such as orebody size and ore grade. During the project evaluation stage, these uncertainties can be included with the dynamic DCF method. This study aims to contribute to increasing the usage of this method in mining projects. A copper reserve in Turkey is selected as a case study to apply uncertainty assessment for the evaluation of NPV.

Jan 1, 2012

By Tad S. Golosinski, R. Larry Grayson

Online education is not new. During the last decade, it has reached the stage where many universities offer a variety of courses, degrees and programs without any associated residency requirements. The most successful of the online universities, University of Phoenix, offers hundreds of accredited programs for close to 100,000 students throughout the world (www.phoenix.edu). Online education is considered to be a valid equivalent to traditional, classroom-based education. It is best suited to the needs of mature students with full-time jobs and a desire to deepen their knowledge. While most of the e-business has experienced severe setbacks during the last two years, e-education shows no signs of slowing down. On the contrary, the number of students and institutions offering online education keeps growing. The value of e-education associated expenditures was expected to reach $300 billion in 2001 (Sanoff,2001), making it a serious and mature industry.

Jan 1, 2002

By D Craw, K A. Hunter

Deposits of the metalloids arsenic and antimony occur in quartz veins of mesothermal hydrothermalsystems in the South Island as arsenopyrite (AsFeS) and stibnite (Sb2S3). Arsenopyrite and stibnite occur in natural exposures in gold-mining areas, and additional arsenopyrite and stibnite have been exposed to the atmosphere by mining activity. At present the drinking water limits for dissolved As and Sb are 10 ppb and 3 ppb respectively. Sampling and analysis techniques are critical to determination of metalloid concentrations at these low levels. Endeavour Inlet in the Marlborough Sounds is an historic mining area (late 19th Century) with elevated As and Sb in waters emanating from mineralised rocks. Waters running out of abandoned adits have concentrations of As and/or Sb up to ppm levels. Natural waters have high Sb and low As, and the As levels increase markedly where anthropogenic activity has exposed rock. Changes in Sb/As ratio could potentially be used to quantify the anthropogenic component of metalloid mobility on mine sites on the 100-year time scale.

Jan 1, 2002

By Anne Lemnitzer

Full-Scale cyclic field testing was performed on a 3x3 pile group consisting of nine cast-in-drilled-hole (CIDH) reinforced concrete shafts and a comparable single-shaft in order to investigate group interaction effects. Both specimens were constructed with pile diameters of d = 0.61m (2 ft), fixed head boundary conditions, and placed in stiff clayey soil at a test site near the LAX Airport in Southern California. Internal instrumentation was installed in the single pile as well as in three piles within the pile group to obtain pile curvatures. External instrumentation controlled the lateral displacement of the specimens. A combination of experimentally and analytically obtained p-y curves for the single pile was used to simulate results for piles located in the group when field data were not available. All test specimens were tested to structural failure and excavated after test completion to investigate pile damage and plastic hinge formations. Calculated group interaction factors ranged between 1.0 at very small displacement levels of <2.5 mm (0.1 in), 0.8 at the initiation of the pile-soil-pile interaction, i.e. between 4 mm - 15 mm (0.16-0.6 in), and increased towards 0.9 near structural failure (displacement >25 mm or 1 in). A literature set of p-multipliers was found to reproduce an accurate fit to the available load displacement test data from the group.

Jan 1, 2010

By R. V. Ramani, J. M. Mutmansky, P. C. Luna, V. A. Marple, Honglin He, B. A. Olson

The development of a sampling instrument for the assessment of an underground coal miner’s exposure to airborne respirable coal mine dust on a continuous and real-time basis has been long identified as essential for timely initiation of control actions. A respirable dust dosimeter (RDD) which operates on the principle of increasing pressure across a filter media with increasing dust mass on the filter has been developed by the National Institute for Occupational Safety and Health. Comparisons of the performance of the RDD with an U.S. approved gravimetric respirable dust sampler (GRD) have shown that the RDD may meet the requirements for measuring miners’ exposures on a cumulative, near real-time basis such as mid-shift and end of shift exposures. Recently, the performances of the RDD and GRD were compared by conducting side-by-side area sampling experiments in a controlled experimental environment in the laboratory and in underground coal mines under normal operating conditions. In this paper, the results from the in-mine study are presented and discussed. The experimental design for the in-mine study included two mines in different coal seams in different geographic coal regions. To ensure a wide range of concentrations, the experiments were conducted in a continuous miner section in Mine 1, and a longwall face in Mine 2. Airborne dust sampling was conducted for four different shifts at each mine. In each shift, two samples of different exposure durations were collected from two different locations. Each sample consisted of the readings of three dosimeters and the exposed filters from the three paired GRD samplers. As a result, a total of 96 comparative samples were obtained, 48 for each mine. The data were analyzed for the precision of the RDD and GRD measurements and for the relationships between the differential pressure of the RDD and the mass of dust on the paired GRD filter. The analyses indicate that, on the average, the RDD and the GRD track the airborne respirable dust concentrations well, exhibiting both a high correlation between the two measurements and a reliable predictive relationship of one from the other. Details of the experimental design, data analyses procedures, results, conclusions and recommendations of the underground experiments are presented in this paper.

IN December, 1905, a Forwood down-wheeler grinding pan (5 ft dialmter), and similar in design to those in use on the Kalgoorlie goldfields, was installed for experimental work in connection with fine grinding jig tailings.The galena remaining in this product is very finely (closely) mechanically disseminated throughout the blende and gangue, rendering fine crushing imperative for its liberation. A reswne of the milling process in vogue at the old mill will enable the series of operations to be more closely followed. The ore at the South Mine assays, on the average-lead...

Jan 1, 1909

By Faruk Oksuz, Clay Haynes, Miguel Sanchez, Patrick Finn, Roger J. Maurer

The Milwaukee Metropolitan Sewerage District’s (MMSD)’s challenges of basement flooding and wet weather sewer overflows are being creatively addressed with the Northwest Side Relief Sewer tunnel. The $132 million, 20-foot diameter, and37,740 feet long conveyance and storage tunnel excavation in dolomite at depths reaching 165 feet below ground surface has been successfully completed within13 months in April 2004. This paper includes Owner’s perspective on the overall project, and the design and construction details by the Designer and the Contractor. The project contract documents included a comprehensive Geotechnical Data Report and the Geotechnical Baseline Report.

Jan 1, 2005

By D. F. Malan

This paper provides an overview of the concepts of citations and journal impact factors, and the implications of these metrics for the Journal of the Southern African Institute of Mining and Metallurgy (JSAIMM). Two key research literature databases publish journal impact factors; namely, Web of Science and Scopus. Different equations are used to calculate journal impact factors and care should be exercised when comparing different journals. The JSAIMM has a low impact factor compared with some of the more prestigious journals. It nevertheless compares well with journals serving other mining sectors, such as the Canadian CIM Journal. The problems associated with journal impact factors are discussed. These include questionable editorial practices, the negative impact of this concept on good research, and the problem of a few highly cited papers distorting the journal impact factor. As a consequence, there is growing resistance to the use of journal impact factors to measure research excellence. The San Francisco Declaration on Research Assessment is a global movement striving for an alternative assessment of research quality. As a recommendation, the Editorial Board of the JSAIMM should adopt a pragmatic approach and not alter good journal policies simply to increase the journal impact factor. The focus should remain on publishing excellent quality papers. Marketing of the Journal, the quality of the published papers, and its open access policy should be used to counter the perception that journals with high impact factors are better options in which to publish good research material.

Sep 1, 2022

By Roozbeh Afzali

Designing an appropriate tunnel blasting pattern reduces the cost of rock breakage and subsequent operations such as loading, haulage and support of tunnels. For that reason, we developed a software that designs tunnel blasting patterns. Using this software, three different tunnel blast design models based on parallel hole cut, namely, Swedish, Konya and Energy Balance, were investigated and compared for a virtual tunnel. Accordingly, blasting patterns were designed, for different cross sections. The trend of parameters such as specific charge and specific drilling as functions of tunnel cross-section was determined for each model. Our results show that, in general, The Swedish model gives lower specific charge and specific drilling compared to other models.

Jan 1, 2008

By John P. Shubilla1, Nicholas Kyriazi

A joint effort by the Pittsburgh Research Center (PRC) and the Mine Safety and Health Administration (MSHA)3was undertaken to determine how well self-contained self-rescuers (SCSR&apos;s), deployed in accordance with Federal regulations (30 CFR 75.1714), held up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSR&apos;s in the fifth phase of testing from mid-1993to early 1996. The SCSR&apos;s were tested on human subjects and on a breathing and metabolic simulator (BMS) at PRC. These results indicate that most of the apparatus, if they pass their inspection criteria, perform satisfactorily.

Jan 4, 1996

By Beevers J

The Ok Tedi Project is now a high production open-pit porphyry copper mine located in the Star Mountains of Papua New Guinea (PNG). At present, total daily production is 190 000t of ore and waste. Large scale drilling and blasting has only been in operation since 1988, prior to which all material was removed by ripping and dozing. This paper reviews the steps taken over the last 12 months in establishing a more efficient drilling and blasting operation and highlights the significant reduction in powder factor. These improvements have been achieved largely through the introduction of air-bags, controlled pattern expansion and an overall focusing on the operation by involving consultants, ICI&apos;s technical service and internal departments.

Jan 1, 1991

By Kevin Whipkey

How is Improvement Being Achieved ? Section Equipment ?Mine Layout/Projections ? Work Schedule ? Maintenance ? Management

Jan 1, 2005

By N H. Jansen, H L. Bridgwater

Field portable X-ray fluorescence (XRF) and near infrared (NIR) instruments are proven technologies in the minerals industry. The in-field results of these instruments can add value early in the project life, leading to cost-effective decision-making compared to their equivalent laboratory based techniques. However, in order to add value to a project, it is crucial that the instruments are employed correctly.Orientation studies should be carried out prior to initiating a sampling program to achieve the highest level of quality assurance and control for the results. Hence, an appropriate sampling workflow begins with considering what outcomes are required, including level of precision, accuracy, reliability for elements and minerals of interest, and sampling errors. The workflows proposed include soil sampling and reverse circulation and diamond drilling sampling techniques, and laboratory based techniques. They are practical and flexible workflows using available portable XRF and NIR technologies that can be applied to current sampling and drilling methods.The combined technologies have the ability to create large, integrated geochemical and mineralogical data sets that can provide cost savings for every stage of the mining chain from exploration to prefeasibility, mineral processing and environmental remediation.CITATION:Jansen, N H and Bridgwater, H L, 2017. Proposed workflows for portable X-ray fluorescence and near infrared instruments for soil and drill hole sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 219–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By T. W. Peglas, J. Doherty, R. A. Day

The South East Transit Project is a $520 million project in Brisbane, Australia which includes the construction of a 32 km Busway to access the south-eastern suburbs. Close to the centre of Brisbane, tunneling techniques have been used to minimise surface disruption. This paper describes some of the features of the longest driven tunnel on the project, the Vulture Street Tunnel. The Busway is a two lane expressway for buses which requires a 10.2 m finished width and a 12.6 m excavated span of driven tunnel. The Vulture Street Tunnel carries the Busway at minimal cover beneath the operating Vulture Street Railway Station, beneath a three storey office building and beneath the roadway to the Mater Hill Busway station. Halfway along the route, a Y-junction has been constructed to enable future connection with a light rail route. Key features in the design and construction of the Vulture Street Tunnel include: Use of canopy tubes to drive a 12 m wide tunnel beneath operating railway tracks with less than two metres of cover in highly weathered rock. Underpinning the office building in the route of the tunnel construction from within the building carpark. Construction of a 24 m span Y-junction with 7 metres cover of weathered and faulted rock. Use of predictive analysis as an adjunct to traditional back analysis to estimate the tunnel settlements from pressuremeter test results. This paper describes the design methodology with particular reference to settlement prediction, as well as construction innovations used to complete the tunnel. This paper will be of interest to all designers who have to create large spans in minimal cover in weak rock in urban areas and who have to predict the settlement

Jan 1, 2001

By George Piscsalko

"Quality control of drilled shafts and CFA piles is greatly dependent upon the practices of the site personnel. In many applications it is difficult or not possible to fully inspect the shaft prior to concreting, such as when the shaft is drilled under slurry. CFA piles are cast with no ability to inspect the shaft prior to concreting. There are numerous methods currently available to assess the integrity of drilled shafts and CFA piles. This paper will compare evaluations by three existing non-destructive test (NDT) methods with a new method of Thermal Integrity Profiling for assessing integrity in drilled shafts and CFA piles. This Thermal Integrity Profiling method determines the integrity over 100% of the shaft cross section, both inside and outside the reinforcing cage, by measuring the hydration temperature of the concrete along the length of the shaft. These temperature measurements are made typically only 12 to 48 hours after concrete placement, thus accelerating the construction process. Thermal Integrity Profiling will be described in detail and the Thermal Integrity Profile (TIP) results from several shafts with purpose built defects will be discussed along with several case histories from drilled shafts and CFA piles where Thermal Integrity Profiling was used. The case histories will compare TIP with various other NDT tests utilized on these particular piles including comparisons with Low Strain Integrity Testing and Cross Hole Sonic Logging. Test results for the various methods will be discussed and the excavation of the upper portion of one drilled shaft will be shown and discussed. IntroductionDrilled shafts can be a desirable foundation element in many applications due to the large axial and lateral capacities which are attainable for very large drilled shafts. Drilled shafts can be cast in a dry hole which allows for inspection of the hole prior to casting, but the casting process is very difficult to nearly impossible to inspect with any accuracy. Drilled shafts are frequently cast under slurry as a means to stabilize the surrounding soils during the construction process. When casting a drilled shaft under slurry, it is very difficult to accurately inspect the hole prior to casting and it is equally difficult to inspect the shaft during the casting process. CFA piles are another popular choice for their relative ease and speed of installation. The trend has been larger CFA piles carrying greater loads, which makes quality control critical for these piles. Many of the above mentioned processes are blind to inspection and therefore the chances increase for having defects present in the completed elements."

Jan 1, 2014

By O. A. Carson

Introduction Although the equilibrium conditions of the copper-tin alloys have been the subject of a ?great amount of research, the equilibrium diagram is still in doubt. The first systematic investigation of the series was made in 1894 by Le Chatelier, who published a freezing-point curve. In 1895, Roberts-Austen and Stansfield published the complete liquidus and partial solidus curves, which they modified somewhat in 1897. Their liquidus as given in 1897 is essentially that accepted today (Figure 3). Haycock and Neville also published a liquid us curve in 1897. In 1898, William Campbell published a series of micrographs showing the changes in microstructure which accompanied the thermal changes of Stansfield? s diagram. The classic work on the bronze series was published by Heycock and Neville in 1903. Their diagram was based on both thermal and microscopic evidence, and is the first for this series of alloys which can be considered nearly complete. Further, it was the first bronze diagram in which any attempt was made to apply the phase rule in the interpretation of the thermal and microscopic results. That portion of Heycock and Neville&apos;s diagram covered by the present work is reproduced in Figure 7.

Jan 1, 1929

By Kimberlee Falkenstein, Volha Kibitkina, Jessica Steeves

A series of experiments were conducted to obtain site specific constants for the vibration produced by a single charge and by more charges detonating in sequence, using short delay intervals. All charges were placed in relatively long boreholes in granite without a free face other than the ground surface. The boreholes were filled with water to provide good coupling with the rock and to provide identical confinement for all the blasts. Vibrations were recorded close to each blast in the vertical direction by uniaxial high frequency geophones and far field using a triaxial geophone.

Jan 1, 2013

By John E. Tilton

Real copper prices during the past several decades display two striking characteristics. First, they are highly volatile. Within a year or two, copper prices can rise or fall by 30% or more. Second, over the longer term, they are falling. Indeed, since 1970, the secular trend price for copper is down by more than 50%. Figure 1 highlights both of these characteristics. It shows the average annual US producer price for copper since 1970 measured in constant 2001 US dollars. While the London Metal Exchange (LME) copper price is not shown, it and the US producer price have for some time moved more or less together. So pronounced short-run fluctuations around a significant long-run decline describe copper prices, not only in the United States, but around the world.

Jan 1, 2002

Chelopech Mining EAD and Best Available Techniques for Management of Waste Rock in Mining Activities

Sep 13, 2010