Search Documents

By Maurice Bottiau

It is a quite challenging objective to aim at covering in one paper the most recent evolution in piling and deep foundations technologies. This report has to be understood within the limits of the session 2b. It will therefore concentrate on the technological evolution of deep foundation techniques, addressing design issues only when directly related to execution aspects. For the same reason, it will not address the related codes, as a separate session of this conference is specifically dedicated to this topic. Monitoring and deep excavations being covered in other sessions, they will only be addressed when clearly relevant. We will try to show, from a practical viewpoint what are the main changes and the most exciting or critical issues over the last years, as they appear from the topics addressed in the literature or in the papers published in this session of the conference. As the paper mostly intends to explain trends and critical topics, it cannot be exhaustive, neither can it give the full description of the case studies. The author invites the reader to read the full papers, for a more complete description. We have divided our report in three main topics: Piling, soil improvement and treatment and retaining walls. Anchors and tie-backs will not be treated, neither tunneling.

Jan 1, 2006

Book review HOEK, E., and BRAY, J. Rockslope engineering. London, The Institution of Mining and Metallurgy, 1974. £5. NIM reports Report no. 1625 The determination of uranium and thorium by the use of delayed neutrons. Report no. 1626 Formation constants of zinc chlorocomplexes in perchlorate medium. Report no. 1629 The thermodynamics of the formation of complexes of silver with some substituted pyridines. Report no. 1630 An electrochemical investigation of the dissolution of copper, nickel, and copper-nickel alloys in ammonium carbonate solutions. Report no. 1640 A semi-automatic titrimeter for cyanide analyses. Report no. 1644 Prospects for the recovery of minerals from the sea. 1974 A.S. & T.S. National Award Professor D. C. Midgley, President of the Associated Scientific and Technical Societies of South Africa, today announced the winner of the 1974 A.S. & T.S. National Award. 1974 G.W. en T.V. Nasionale Toekenning Professor D. C. Midgley, President van die Geassosieerde Wetenskaplike en Tegniese Verenigings van Suid- Afrika het vandag die wenner van die 1974 G.W. & T.V. Nasionale Toekenning aangekondig.

Jan 9, 1974

By L. Sahu, S. Bhattacharya, S. Dey

"An ideal procedure to determine the limits of flotation-based separation, as is the case with washability analysis for density separation, does not exist. Therefore, a procedure called release analysis, considered to be the counterpart of the washability process in density separation, was developed to evaluate the flotation characteristics of coal fines. Since flotation is a complex process it is necessary to know the maximum recoverable yield that could be achieved at a target ash level and what could be obtained by release analysis. Due to a number of limitations in the initial procedures, modifications were recommended by various researchers to generate an optimum separation curve. This paper presents a review of, and a discussion on, the chronological evolution of release analysis methodology over the decades. Notwithstanding the availability of a standardized release analysis procedure, such as BS 7530, the paper highlights the critical parameters involved in the procedures, such as coal type, feed characteristics, choice of reagents and dosage, operator bias, and design features of the flotation cell IntroductionCoal is a heterogeneous substance consisting of various combustible constituents (macerals) and associated mineral matter. The kind and abundance of the various macerals present in the coal, such as vitrinite, semivitrinite, exinite, and inertinite, determine the type of coal. As macerals are formed by biological degradation of different parts of the plant material, they have different properties based on their original composition. Coal cleaning processes are dependent on the differences in physical properties between the coal components (the macerals) and also between the macerals and the mineral matter. Thus the cleaning characteristics of the coal might vary from one type to the next. The cleaning processes influence the distribution and the concentration of macerals in the various size and density fractions of the cleaned product."

Jun 1, 2019

By R. A. Franks

An evaluation of a nuisance-emissions-discriminating smart mine fire sensor system was made in an operating coal mine. These field evaluations were conducted to determine the sensor system?s ability to discern nuisance emissions, such as diesel exhaust, emissions from flame cutting and welding operations or hydrogen gas from a charging station, from real fires and to compare the number of falsely reported fire alarms generated between the sensor system and a standard carbon monoxide (CO) monitor. The sensor system?s ability to operate successfully in the working environment of an operating coal mine was also evaluated. The smart mine fire sensor system consisted of four sensors whose data outputs were fused with the use of a neural-network-type computer program. Long-term trials were conducted in a haulage way, a belt entry, and a track entry. The system functioned successfully in the belt entry, in accordance with its developmental goals, where the sensor system even discriminated events not anticipated during development. It was not totally effective in the haulage way and track entry, though, due to a combination of significant diurnal air temperature variations, dust, and mechanically induced vibrations. Also, deteriorating rib conditions contributed to operational problems in the haulage way evaluation. In general, the smart mine fire sensor provided nuisance emissions discrimination and was shown to be a viable new approach for mine atmospheric monitoring, enhancing miner safety. This paper describes the in-mine evaluation of the smart mine fire sensor system and discusses recommendations for improving the system. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2008

By Robert G. Nisle

The classic theory of pressure build-up in shut-in oil wells as developed by Horner and van Everdingen is based on two-dimensional radial symmetry in the well-reservoir system. Such symmetry does not exist in the case of a well which parfiially penetrates the producing formation. As a result of this lack of symmetry the use of the classic theory in such cases become questionable. In this paper the mathematical theory has been extended to include the case of partially penetrating wells. Numerical solutions illustrating the up-dication of the equations are presented. The effect of partial penetration on pressure build-up is shown by a comparison of synthetic pressure build-up curves derived from the numerical solution of the equation for partially penetrating wells for various degrees of penetration. It is shown that partial penetration is detectable from the characteristic shape of the pressure build-up curve and that formation productivity may be calculated from the pressure buildup data in a manner identical to that described by the classic theory. INTRO DUCTION The use of pressure build-up data on shut-in oil wells is a well-established technique for the measurement of reservoir productivity. The work of Homer' and van Everdingen' is well known. Since the publication of their pioneering work, others"' have elaborated and extended the technique. These authors have dealt exclusively with the case of wells that completely penetrate he producing formation. Two-dimensional radial symmetry is achieved, thereby, and the problem is greatly simplified. This ideal situation is seldom encountered in practice. But, in spite of this, the technique is often employed anyway. The question, therefore, arises: how much confidence can be placed in the results of such calculations when the data are taken on wells that only partially penetrate the producing formation? It is the purpose of this work to answer this question. Only the single-phase fluid case will be considered. van Everdigen' has presented a rigorous solution of the two-dimensional case, but because of mathematical complexity, this solution has not proved to be particularly useful. Horner' utilized Kelvin's point source solution in two dimensions and showed that it is a sufficiently good approximation for oil reservoir studies. The geometry of the well and the producing formation is illustrated in Fig. l. Geometrically the formation may be described as an infinite slab. The infinite slab is defined as the solid (the porous medium in this case) bounded by two parallel planes. Thus, the slab extends to very great distances in both the positive and negative directions of two of the coordinate axes, but is finite in

By Brian Hart, Stamen Dimov

"The Time of Flight Secondary Ion Mass Spectrometer (ToF-SIMS) is unique in that it measures the outermost atomic layers of any material. The technique is particularly suited for determining surface chemical composition of mineral particles. It is most commonly used as a diagnostic tool to measure mineral surface chemical variability in plant and bench top flotation separation processes. Recently, research towards understanding the full capability of the instrument has resulted in the development of new diagnostic applications related to various Au extraction technologies and the development of the ToF-SIMS as a predictive tool for assessing the chemical reactivity of the ore.In this paper we will present a brief review of the ToF-SIMS technique with recent advances in instrumentation and methodologies including:•,?recent developments and advances towards a semi-quantitative approach to the evaluation of mineral surface modifiers (ex. Cu),•,?flotation case studies investigating activator, depressant and collector loading variability within a flotation process,•,?the recently developed chemical reactivity test which we believe has the potential to predict the behaviour of minerals in a flotation test in response to chemical transfer during grinding,•,recent applications for determination of surface Au preg-robbed in carbonaceous materials.A portion of this material has been recently presented at the COM 2009 meeting and at SIMS XVII (see Dimov et al 2009 and Hart et al, 2009).INTRODUCTIONIn flotation seperation surface chemistry is the principal determinant for selective separation of the various mineral phases (Ralston, 1994, Smart et al, 2003). Determination of this hydrophobic/hydrophilic balance by particle therefore requires correct identification and selection of the particular mineral phase(s) followed by a statistical analysis of the surface chemical characteristics of the particles with an estimation of the spread of values (Smart et al, 2003)."

Jan 1, 2010

By B. C. Viljoen

"SynopsisCommencement of the next phase of the Lesotho Highlands Water Project is a year or so away from becoming reality. Some 50 km of tunnels in the form of access adits, shafts, diversion tunnels, and main waterways will be constructed. Sprayed concrete will form an integral part of the temporary and permanent rock support systems that will be installed. Furthermore, the use of sprayed concrete as a final tunnel lining solution was proposed as a viable alternative to concrete linings in the feasibility studies that preceded the forthcoming implementation phase.The aim of this paper is to make the reader aware of all the sprayed concrete related issues that engineers tend to grapple with during the design and construction of tunnel projects and other underground works. Primarily, these issues would include selection of applicable design parameters, technical specifications, construction application methods, quality control and, most importantly in the context of final or permanent linings, the durability of sprayed concrete.The International Tunnelling Association (ITA) Working Group (WG) 12 has been tasked specifically to publish a set of recommendations on the Quality and Control of the Application of Sprayed Concrete and the Testing of Sprayed Concrete for Durability. These tasks were also further explored at the recent World Tunnel Congress (WTC 2015) that was held in Dubrovnik, Croatia at the end of May 2015.IntroductionSprayed concrete is presented in a variety of shapes, designs, forms, application methods and accompanying terminologies including shotcrete, gunite, pneumatically applied concrete, and the like. The International Tunnelling Association (ITA) decided to standardize on a single terminology, namely ‘sprayed concrete’, in order to simplify specification, interpretation of guidelines, and codes of practice."

Jan 1, 2015

By A. A. Berk

Other Federal agencies have been coming to the Bureau of Mines for help with the purchase and utilization of fuel, largely coal, almost since the day the Bureau was created in 1910. The requests covered a wide range of fuel- economy problems and included boiler-water treatment after it became apparent that water-formed deposits on heating surfaces acted as insulators, decreasing heat transfer and impairing fuel efficiency. Dr. Ralph E. Hall, a Bureau of Mines physical chemist determined the 3 reactions that cause adhering scale to form in boilers (7)2 and went on to introduce scientific principles into water treatment for scale prevention (8). Widespread publicity of these achievements increased the requests for help from Federal steam-generating plants. Since no other Federal agency (even those which were more directly concerned with testing water) wanted to provide boiler-feedwater service, the Bureau decided to continue to give requested help to Federal agencies, Later, the Congress endorsed such agency cooperation as an economy measure,

Jan 1, 1963

By Randy R. Huberty

Although originally designed with deep foundations consisting of all driven steel H piles and drilled caissons, a unique application of Augered Cast-in-Place (ACIP) piles as an alternate design resulted in a significant cost savings for the Midfield Terminal Project at the Pittsburgh International Airport. The project was enormous in scope covering an area two miles long by one mile wide, with changes in elevation of over 200 ft. The varying geology combined with the large amounts of fill required resulted in a complex set of geotechnical design parameters that had to be evaluated through both load testing and analyses. A total of almost 400,000 lineal feet of ACIP piles were installed for this project.

Jan 1, 2001

As part of its research and development activities concerning coal mine operational/emergency communications sys terns, the Bureau of Mines commissioned several contractors to conduct electromagnetic (EM) noise studies and measurements that would aid the development of improved coal mine operational/emergency communications systems. The bulk of the noise studies and measurements were conducted in 1971. The Pittsburgh Mining and Safety Research Center (PMSRC) inherited the responsibility for monitoring the electromagnetic noise activities by mid-to-late 1971, and initiated a review and evaluation of the current and planned electromagnetic noise work. Arthur D. Little, Inc., (ADL) was asked by PMSRC to assist it in performing this review and evaluation by placing stronger emphasis on certain tasks of existing Contract No. H0122026. This technical memorandum report presents the findings, conclusions, and recommendations of our review and evaluation of the electromagnetic noise measurements of the five contractors we were asked to examine. Our review and evaluation effort included meetings and telephone discussions with technical staff of each contractor; serving as Technical Discussion Leader of a "Contractor's Round Table Meeting on EM Noise, Surface and Subsurface, Operating and Non-Operating Mines" called by the Bureau of Mines; examination and discussion of contractor reports and relevant open literature; sample verification calculations; and the documentation of our findings, conclusions, and recommendations by this report.

Jan 1, 1972

By B. Schoevaerts

The ever-increasing depth of mineral extraction presents a challenging environment for hard-rock underground mines. High in situ stresses and associated seismicity with potential rockburst hazards are the major decisive factors contributing to the choice of a ground support regime. Conventional ground support systems, designed primarily for static loads, are not always capable of providing safe working conditions for underground personnel in seismically active mines. Systems specifically developed to resist dynamic loading and allowing for larger deformations are therefore preferred alternatives. High-tensile chain-link mesh has a proven record of successful use in open cut operations in various rockfall barrier installations due to its high energy absorption capacity. It has also been used in underground operations in various parts of the world. Its application in South African underground mining, however, is limited due to the high labour intensity. This paper describes a method of mechanized installation of a chain-link mesh as evaluation at Gold Fields' South Deep Gold mine situated some 45 km south-west of Johannesburg. A purpose-built mechanized roll mesh handler, developed in Australia, was used in this trial. The handler is compatible with all standard multi-boom underground drill rigs and is operated utilizing the hydraulic circuit normally used for the feed arrangement. A number of key performance indicators have been specified as success criteria by Gold Fields: ? A 30% faster installation compared to the conventional methodology ? The mesh should sustain any blast damage when applied to the blasting face ? No unravelling of the mesh when cut ? No failure of mesh under normal conditions ? Reliability of the MESHA® installation handler (availability >90% ? Compatibility of the MESHA® installation handler with AC 282 boomers. Although the energy-absorbing mesh combined with yielding rockbolts is a ground support system of choice for rockburst-prone conditions, the operational upsides recognized during the trial imply that this product can also be competitively used in less demanding ground conditions where weld mesh or shotcrete are customarily used as a primary surface support.

Jan 1, 2012

Sulfidisation Promotion Effect of Ammonium Sulfate on the Flotation of Copper Oxide Ores

Sep 13, 2010

By Dan Witkowsky

Beginning on June 11, 2007, as many as 36, kindergarten-to-grade-12 (K-12) teachers will participate in a program designed to educate them all about the mining industry. The 39th Annual A Total Concept of the Mining Industry – All About Mining, will be conducted by the Colorado Mining Association Education Foundation, Inc. (CMAEF) and the Office of Special Programs and Continuing Education (SPACE) at the Colorado School of Mines. This flagship program includes four intensive weeks at the Colorado School of Mines. During that time, more than 75 volunteer lecturers will “educate the educators” about mining and its importance to the United States and the world. During the learning process associated with obtaining a basic understanding of mining and all its aspects, the teachers will be hosted by hundreds of other industry professionals at 10 Colorado mining operations. Also visited will be a government earthquake center, a museum of mining and industry, an earth mechanics laboratory, a metallurgical research center, a metallurgical concentrator, an electric power plant and a steel mill. Questions before, during and after visits will be answered by another select group of volunteers who will travel with the teachers to the various sites.

Jan 1, 2007

By Yoginder P.

ACKNOWLEDGEMENTS Authors sincerely appreciate the interest, cooperation and technical support of the coal company management and staff in conducting the study. Without their assistance this study would not have been possible. INTRODUCTION AND SPECIFIC OBJECTIVES An area in the midwest overlying abandoned room-and-pillar mine workings at, shallow depth has been experiencing subsidence movements with associated damage to surface structures. Other coal companies in the area have also been having similar experience. A 16 - month cooperative study between a mining company and the Department of Mining Engineering at SIUC was developed with the following objectives. 1) Determine the extent to which surface and subsurface movements were complete in the area, 2) Identify the mechanism(s) of subsidence in the area, 3) Determine the influence of geology and hydrology of the area on subsidence movements, 4) Observe the conditions of abandoned underground workings with a borehole TV camera, 5) Characterize the extent of damage and monitor possible progressive damage to selected surface structures, and 6) Make recommendations to a) minimize further damage to surface structures in the area, b) identify future areas that may be affected by these movements and c) modify mining systems to minimize these movements.

Jan 1, 1986

By Paul J. Lewis

Estimation of the axial side shear resistance of drilled shaft rock sockets is directly related to the unconfined compressive strength of the bedrock. Commonly, the mean unconfined compressive strength value is calculated from a range of laboratory test results and is used to estimate the side shear of the bedrock. This paper presents the results from a full scale axial load test performed on an 8.5-feet-diameter drilled shaft rock socket, and compares measured side shear values to estimated values for two different rock strata. Measured side shear values correlated well with the design value calculated for the "strong" rock stratum, but did not correlate well with the design value calculated for the "weak" rock stratum. The mean unconfined compressive strength was used to calculate the side shear in both strata, but review of the laboratory data indicates that this value may not have been appropriate for the weak stratum due to a large variation in the laboratory test results. Also included in this paper is a discussion of the subsurface conditions, the laboratory test results, and the methodology used to design the drilled shaft rock sockets for axial and lateral resistance.

Jan 1, 2005

By G. W. Jones

In a previous report,6 results were given that showed the amount of natural ventilation in a manhole having a capacity of 74.l cubic feet when the number of ventilation openings in the cover was varied. from no openings to a maximum of 48. The results showed that the ventilation (air changes per day) in the manhole was proportional to the area of the openings in the cover, and also that the number or area of the openings was the factor that chiefly affected the ventilation.

Jan 1, 1937

By Jose A. Gomez, Javad Sattarvand

Failures of tailings dams have been happening lately. Due to the lack of laws on particular design criteria and stability requirements related monitoring during construction and maintenance, they are thought to be more fragile than hydraulic dams. Monitoring the dam is therefore necessary to understand its current condition and guarantee its safety. The physical condition of the dam could be evaluated with the early identification of seepage. Additionally, due to their adaptability and capacity for high-resolution data collecting, UAVs are an excellent choice for efficiently covering the tailings dam site. UAVs may capture high-quality photos when equipped with a high-resolution RGB camera, thermal sensors, or multispectral sensors. When these sensors are paired with image processing and machine learning algorithms, the result is a reliable estimate of the dam condition.

Jun 25, 2023

In the past decade several significant intrusion-related gold deposits have been discovered in terranes historically exploited for tin-tungsten mineralization (eg Tintina Gold Province, Yukon and Alaska, Tasman Fold Belt, Australia and the Altaid orogenic collage in central Eurasia). This paper presents new data on the geological and geochemical characteristics of these deposits that links them to magmatic-hydrothermal processes and highlights their implications for exploration. New data from several intrusion-related gold provinces suggest that these deposits are found in areas that contain granodiorite to granite, but with a locally significant mafic component, have Rb/Sr ratios ranging between 0.1 and 1.0, and are moderately reduced (Fe2O3/FeO ~ 0.1 to 0.6) ilmenite series, metaluminous, I-types. The intrusions are distinct from porphyry copper intrusions and tin granites, but are more akin to tungsten granites. Hydrothermal fluid types vary with depth of emplacement in intrusion-related gold deposits and new proton induced X-ray emission (PIXE) data from syn-ore fluid inclusions in shallow and deep deposits provide fascinating insight into the variation in metal content between the different settings consistent with observed deposit metal associations. Exploration for intrusion-related gold deposits in tintungsten terranes should focus on regions that contain both mafic and felsic intrusion that are moderately reduced, metaluminous, I-type granites rather than terranes with dominantly highly fractionated, strongly reduced, peraluminous S-types. Intrusion-related gold systems occur in variety of deposit styles (in part controlled by host rock, proximity to granite, and depth of emplacement) and exploration geologists need to be aware of the variety of target types in and around the intrusive environment, and be able to recognise whether they are exploring a shallow or deep intrusion-related gold setting.

Jan 1, 2005

By Don Thompson

It isn?t a lie if you don?t tell the whole truth The pictures National Geographic didn?t print Other photos National Geographic didn?t print?

May 1, 2009

By Z X. Zhang

Ground vibrations from the blasts of the LKAB mine at the Malmberget town had reached 18-19 mm/s from year 2000 to 2002. From 2004 to 2010 the maximum vibrations had been reduced to 9 mm/s and most vibrations lowered to about 5 mm/s, indicating that the technical measures used in the mine are effective in vibration control. The major measure that has always been used in Malmberget mine is the method called Changing Initiation Sequence (CIS in short). Another method named Dividing Ring Blasting (DRB in short) is often applied to some special blast rings in the mine. Both methods have been proved to be successful in vibration reduction, and they do not need any additional costs. Because of the two methods, both maximum vibrations and average ones have been reduced by around 50% since 2004.

Jan 1, 2012