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By George Mylonakis

The curvatures and subsequent bending imposed to piles by the surrounding soil during the passage of strong seismic waves is studied. This type of bending develops even in the absence of a superstructure and is referred to as "kinematic bending", to distinguish it from bending imposed to piles by loads generated from the inertia of the superstructure ("inertial bending"). Although kinematic loading may be severe in the presence of sharp stiffness discontinuities in the profile and may lead to damage, it has received little attention by engineers. The scope of the paper is twofold: (i) to discuss some fundamental aspects of seismic pile bending, and (ii) to review some existing design methods. To this end, a dimensionless bending strain parameter (instead of the more commonly used bending moment), and a strain transmissibility function relating pile bending strain and corresponding soil shear strain are introduced. Numerical examples are also presented.

Jan 1, 2002

By P. Mousset-Jones, G. Danko

Variations of the temperature and steam/moisture content of the air with distance and time are modelled for a single airway. The input for the simulation is an air temperature that varies with time, together with the moisture/steam content that results, for example, from a fire with a given distribution of heat and of fume concentrations at the beginning of the airway. The transport of heat and moisture to the surface of the wallrock is assumed to be simultaneous. Such multiphase convection may result in evaporation from the moist wall close to the fire and recondensation downstream. The modelling of this non-linear effect is a unique feature of the new simulation. A new analytical solution is used to calculate the conduction of transient heat within the rock mantle, which, in the event of a fire, is typically a short-term process. This allows for an arbitrary variation of surface temperature with time - unlike that permitted by the age function solution, which is limited to stepped temperature changes. An iterative numerical scheme that has recently been developed to simulate mine climate is used to calculate the coupled transient heat conduction and multiphase surface heat transport in successive length increments along the airway. To demonstrate the simulation procedure a numerical example is presented in which a fire with a given distribution of heat and fume concentrations with time is located at the beginning of an airway

May 1, 1991

By Roy C. Fedotoff, Jon Hurt, Gregg Sherry, Gilbert Tang

The 1,380 m (4,200 ft) long New Crystal Springs Bypass (Polhemus)Tunnel (NCSBT) will replace the existing Crystal Springs Bypass Pipeline. This tunnel project is part of the SFPUC’s $4.3 billion capital improvement program to repair and seismically upgrade their aging pipelines, tunnels, reservoirs and dams that provide drinking water to more than 2.4 million customers in the San Francisco Bay Area. This paper describes the development of the tunnel alignment and design, and the complex ground conditions of the Franciscan Mélange. Of particular interest is the challenge of tunneling with a possible downhill grade of 3%, a rigorous environmental process and incorporating the lessons learned from 1960s construction of the adjoining Crystal Springs Bypass Tunnel.

Jan 1, 2007

By R. S. Dean

The brief resume of the activities of the Metallurgical Division that appears annually in its progress reports series serves a useful purpose by making available a rather comprehensive but concise recapitulation of the current work, and publications of the division. An unprecedented opportunity to attack the problem of producing ferro-grade material from low-grade domestic manganese ores effectively was provided by the act designated as Public 667 of the 76th Congress of the United States, approved June 26, 1940, which made available an appropriation for "Expediting Production of Equipment and. Supplies for National Defense." Although the funds were not immediately available to the division, good progress has been made in the, solution of the many and diverse problems presented in the studies undertaken to determine the best methods for the recovery of useful products from a wide variety of manganese ores.

Jan 1, 1941

By J. Allaire, P. N. Muteb

The Meadowbank mine is operated by Agnico-Eagle Mines Ltd. and is located in the Kivalliq District of Nunavut in northern Canada. The process plant operates presently at a throughput of 11,500 tpd with gold grade varying between 2.9 and 3.6 g/t. The ore supplied to the process plant come from two different open pits and it expected to come from a new open pit early 2014. The ore is mid-hard materials so the feed size ore have a bigger impact on the throughput. The average gold recovery is 94.0% with about 15-30% of gold recover from the gravity circuit. The Meadowbank mine commissioning started in February 2010 utilizing a flowsheet consisting of one stage of crushing followed by primary and secondary grinding. The commercial production began in March 2010. During the commissioning several difficulties were observed to reach the designed throughput of 8,500 tpd. It was evaluated to insert a second stage of crushing. The insertion of the secondary crushing have two objectives, first to reach easily the process plant design throughput as well as to evaluated the mill capacity increasing. The process plant team evaluated various expansion alternatives eventually deciding to install a secondary crusher, increased the SAG and Ball mills motors capacities and maintain the rest of the process unchanged. Early 2011, with the improvement in the gold markets, decision was made to install the secondary crusher between the primary crusher and the primary grinding. The process plant continued to operate on the initial design until early June 2011. This paper presents the SAG mill throughput increasing from the designed tonnage of 8,500 tpd to 2012 targeted tonnage of 11,500 tpd, secondary crusher commissioning and the difficulties to operate in Canada Artic (Nunavut).

Jan 1, 2013

By Clyde N. Baker

Foundations for the Sohio Corporate Headquarters in downtown Cleveland have column loads of 11,400 kips, which increase to 15,000 kips with wind loading. An extensive exploratory program was conducted and comprehensive studies made to select the economically dependable support for the 46-story structure. A test on bond or socket friction for the caissons has usable values.

Jan 1, 1984

By S. Möllerherm

"The evaluation of data and information provided by the existing traditional indicators in sustainability assessments is most important. Therefore the Institute of Mining Engineering I from the RWTH Aachen University developed indicators and an assessment system for the mineral raw materials industry on operation, company and sector level on behalf of the Federal Ministry of Economics and Labour (Bundesministerium für Wirtschaft und Arbeit, BMWA) and the Federal Institute for Geosciences and Natural Resources (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR). In the course of the development of indicators for the raw materials industry quality indicators on different levels of the sustainability assessment procedure have been identified and developed. The following paper describes some of the results focussing on the development and integration of quality indicators into sustainability assessment systems."

Jan 1, 2005

By Anthony D. Szpak

The purpose of this program was to demonstrate the feasibility of Illuminating various types of underground coal mining machinery as required by the Federal Coal Mine Illumination Standards Part 75.1719 to 75.1719-4 Code of Federal Regulations Title 30. Nine various machines were illuminated and the illumination systems were evaluated for a 3 month period of operation. Factors evaluated were ease of implementation, reliability, ease of maintenance, acceptance by mine workers and operators, Illumination degradation and durability.

Jan 1, 1981

By J. M. Davidson

The potassium mineral polyhalite (K2SO4.MgSO4.2CaSO4.2H20) found in large deposits in western Texas and southeastern New Mexico is associated with varying amounts of halite (sodium chloride, NaCl) and anhydrite (calcium sulphate, CaSO4). Although the anhydrite, because of its low solubility and slow rate of solution, is relatively inert, the halite is dissolved immediately in any process solution with which the polyhalite comes in contact. Limited quantities of sodium chloride in the liquors used for the hot extraction of polyhalite materially improve the results obtained,4 but only a very small sodium chloride content may be desired in the entering polyhalite in other procedures, such as Bureau of Mines process 75. In. all of the processes suggested for the recovery of potassium sulphate from polyhalite the control of the sodium chloride content will be desirable, if not absolutely essential to efficient operation. OCCURRENCE OF HALITE IN POLYHALITE A preliminary estimate of the amount of halite associated with typical deposits of polyhalite may be derived from drill cores, although it should be remembered that only 50 or 60 core tests have been made in the many hundreds of square miles of the Permian basin. From a mineralogical study of 41 of these cores, Schaller and Henderson6 state: In many of the sections of core that seem when viewed by the unaided eye to consist essentially of polyhalite, both halite and anhydrite are present in greatly varying quantities - with very minor quantities of clay and magnesite.

Jan 1, 1934

By D R. Cohen

As one of the four basic sciences, the study of geology is intrinsically worthy as a means of increasing fundamental knowledge of the behaviour and evolution of the universe. Geological knowledge can also be translated into practical outcomes for society such as resource discovery and protection of the environment. Australia has a long tradition of providing very high quality geoscience programs to prepare graduates for a range of occupations. We are, however, reaching a nexus in the way universities should or can deliver engaging programs. This has been triggered by the rapid evolution of the digital world (the Internet of Things), new technologies, unprecedented access to information, better understanding of the processes by which we learn and adapt our thinking, growing complexity in the problems we must face or opportunities to grasp, and university funding models. Designing education programs for the next generation of geologists extends far beyond tinkering with syllabuses. We must develop skills sets that will allow graduates to work in rapidly changing landscapes, but in doing so may have to sacrifice content to build capability in our graduates. Whereas universities must respond to changing demands on graduates by ensuring degree programs contain an appropriate balance of material and high quality of delivery, industry and government must also fulfil their responsibilities to provide additional training programs for graduates to assist their rapid transition into independent professionals. This paper examines various educational issues being considered in developing the new Decadal Plan for the Earth Sciences, and reflects on directions that education is heading in many of our universities.CITATION:Cohen, D R, 2017. Educating the next generation of geologists, in Proceedings Tenth International Mining Geology Conference 2017, pp 3–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By G. L. Fitzpatrick

A portable optical instrument for performing multispot laser vibrometry is described. The instrument is capable of measuring arrival times, surface motion frequency, and surface velocity and displaying these quantities in various useful ways. Sigma Research is currently pursuing the development of such optical measuring systems for the evaluation of structures in rock by non-contact interferometry methods. This work was sponsored by the U.S. Department of Interior (U.S. Bureau of Mines) under a Small Business Innovation Research (SBIR) contract number J0145075. The goal of the work was to develop a portable tripod mounted measuring system which can be set up at arbitrary distances (up to 30 meters) from a surface and project four in-line laser sample beams on this surface. A light receiving telescope gathers the scattered light from these four spots and provisions are made to mix this light with a reference beam from the laser. Four photodiodes are employed to determine the resultant interference signals which characterize the motion (particle velocity, frequency, amplitude) of the four illuminated spots on the surface under sudy. Information of this type can then be used to characterize the elastic or mechanical properties of the surface in question. In some cases (if more than four spots are involved) this surface information could be back propagated to draw inferences about the internal state of the material volume bounded by this surface.

Jan 1, 1987

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 Richard A. Allwes

This Bureau of Mines report presents a procedure for the design of an arch canopy for use in rehabilitating a high-roof-fall area. Only dy-namic line loading of an unbackfilled arch canopy at its crown is considered, and the procedure does not account for an asymmetrical loading condition. The evaluation of whether an arch canopy is suitable for a particular installation depends on many variables, including in-mine conditions and the engineering properties of the structure. However, a general evaluation can be based on a comparison of the arch's maximum crown deflection and a prescribed allowable crown deflection. The design procedure is based on the concept that when an arch canopy is sub-jected to impact loading at its crown and deflects from its unloaded state to maximum crown deflection, the structure absorbs strain energy, both elastic and plastic. As a result, this strain energy can be calculated from a static load-displacement diagram for the structure. The significance of this design procedure is that it gives mine personnel an analytical tool to select an arch canopy to meet the dimensional and functional requirements of a mine entry and a prescribed allowable crown deflection.

Jan 1, 1987

By Mary E. Cocklan-Vendl

Regulatory processes associated with development of major mining operations in Alaska and British columbia were evaluated using specific case studies. Included were one hard rock mine in Alaska (Red Dog Mine), one hard rock mine In British Columbia (Snip Mine), and one offshore gold dredging project in Alaska (WestGold SIMA). Based on a comparison of the three case studies, it became clear that the primary incentives for cost effective permitting are: 1) early and continuing coordination of proposed project plans, designs and schedules with key regulatory agencies and local area residents and 2) development of a sufficient level of baseline information on air quality, water quality, wetlands, endangered species, fish and wildlife, and socia-cultural conditions to support the required permit application. The U.S. permitting process worked in much the same way as the Canadian permitting process. Disincentives of mine permitting include high initial costs for baseline data gathering. However, a relatively high early investment resulted in more efficient permit acquisition and reduced long-term monitoring requirements. A common problem Identified was the inadequate supply of trained agency personnel with the requisite technical and permitting experience. This sometimes resulted in poor decisions and unnecessary changes in project plans and schedules.

Jan 1, 1993

By A. de Meyer

Zincor experienced significant losses of metallic zinc to dross during the melting of zinc cathode plates. In this study five factors affecting the formation of dross are identified from literature. Dross from both the plant and that produced in the laboratory is characterized using XRD. An empirical model, based on laboratory-scale investigations, was developed to quantify the effect these factors on their own or in combination with each other has on the amount of zinc loss to dross. The predictive capability of the model is evaluated based on the laboratory-scale investigations. Predictions are made on the effects that heat treating the cathode plates prior to melting, increasing the cathode plate thickness, washing and drying prior to melting, and loading the furnace in a controlled manner have on the amount of zinc loss to dross. Keywords: Zinc, dross, optimize, smelter, yield, losses, empirical, model, XRD.

Jan 1, 2010

By J. Torma-Krajewski, M. Lehman

In 2005, NIOSH and Badger Mining Corporation entered a partnership to implement ergonomic interventions, including a systematic process, to address exposures to risk factors that may result in musculoskeletal disorders or other types of injuries/illnesses. As a result of this partnership, an ergonomics process was integrated with the existing safety and health program to promote an on-going application of ergonomic principles, and over 40 task-specific interventions were implemented during the first year of the process. This paper presents details of the process integration, and several examples of task-specific interventions that reduced exposures to risk factors.

Jan 1, 2007

The New Zealand Minerals Industry is small but growing. Over the next 10 years it will be facing stiff international competition for skills to support this growth, particularly from Australia who are forecasting that a further 70 000 people will be employed by 2015.   The value of commodities mined and quarried in NZ continues to increase; and the value of coal, metals and industrial minerals production reached $1.505 billion in 2006, an increase of 15 per cent on 2005. Production increases will continue à. Latest Crown Minerals statistics show that national prospecting and exploration expenditure rose to $29.9 million in the year ended March 31 2006 û an increase of 46 per cent from the $20.4 million spent in the March 2005 year. The equivalent 2001 year expenditure was only $2.48 million.   The industry already experiences difficulty in recruiting the people it needs with ongoing demand for skilled underground miners, trades people, and mining professionals. This discussion paper will outline the national context with regard to labour, skills and training. It will suggest options and provide an opportunity for conference participants to discuss the way forward.

Jan 1, 2007

By Tian Sugui

By direct aging treated, creep properties measurement and microstructure observation, the influences of the direct aging treatment on the creep behaviors of Hot Continuous Rolled GH4169 superalloy are investigated. Results show that the creep resistance of Hot Continuous Rolled GH4169 superalloy may be obviously improved by directly aged treatment. Under the applied stress of 700MPa at 660, the creep lifetime of the alloy is enhanced to 126h from 60h. During hot continuous rolling, the deformation features of the alloy are the twinning and the double orientations slipping of the dislocation activated within the twinning regions. After direct aging treated, the alloy displays a smaller grain size, and the finer g² phase is dispersedly precipitated in the matrix of the alloy, which is thought to be a main reason of enhancing creep lifetime of the alloy.

Jan 1, 2010

By T. Y. Yunsel

Estimation techniques such as polygonal, triangular prism, trapezoid, isopach maps, and inverse distance methods are often used in ore or industrial minerals deposit evaluation. These techniques do not express the variability of the deposit and do not allow a determination of the reliability of the estimates. However, geostatistical methods can express a measure of the error associated with the estimates, by finding weighting coefficients for a given mining block, and can also help with data configuration that minimizes the error. This work addresses an application study on the quality and reserve characteristics of the cement raw materials of the Adana Cement Factory in Adana, Turkey, based on the spatial distribution and variability of the chemical components (Si02, CaO, A1203, Fe203). The study has been carried out using a geostatistical procedure that is useful for site assessment, characterization, and monitoring situations where data are collected spatially. Directional and omnidirectional experimental variograms of the cement raw material variables showed that neither strong geometric nor severe zonal anisotropy exists in the data. The most evident spatial dependence structure expressing the continuity for omnidirectional experimental variograms were characterized by exponential and spherical variogram models. These models have been used in cross¬-validation analysis, which proved that these models, their parameters, and kriging parameters are applicable for the study area. Quality contour maps of the deposits at given levels underground were estimated using a kriging interpolation technique. Anomalies such as bullseyes and drift were not observed in the maps that were generated. Kriged maps showed the spatial distribution of quality continuity and variability of the deposits. Grade-tonnage curves and total tonnage estimates in the particular grade were determined using ordinary kriging in order to improve the mining operation and planning. Consequently, local uncertainty and the probability of extreme values occurring are tools of prime importance for the mine planning, the optimum mix of raw materials coming from different quarry stopes.

Jan 1, 2012

By F. Dehghani

The influence of different grinding methods on the shape characteristics of magnetite particles was investigated. Also, the effect of particle shape on the flotation of the magnetite, both alone and in the presence of quartz particles, was investigated. The shape characteristics of the magnetite particles were measured and calculated from images obtained by scanning electron microscopy via an image analysis system. The flotation tests were performed using a laboratory flotation cell. Results showed that in the -250+212 µm and -106+75 µm size fractions, ball mill products have a higher elongation value than rod mill products, while in the -150+125 µm size fraction, rod mill products have a higher elongation value. Particles with higher elongation values and lower roundness values have a higher flotation kinetic constant. Furthermore, the influence of magnetite particle shape on flotation is greater, and the flotation kinetic constant is higher, in the presence of quartz particles than in the flotation of magnetite alone Keywords shape, elongation value, flotation kinetics, magnetite.

Dec 1, 2013