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By M. R. TECK, N. Rudd, L. K. Thomas, D. L. Katz

The authors are to be congratulated for presenting the first comprehensive paper on the theory and practice of threshold pressure determination in connection with underground gas storage. It is of particular value since most previous experimental work on this subject has been proprietary to the commercial laboratories engaged in such testing and to their clients. This dlscussion is presented in amplification of the subject paper, not in criticism, and is based upon our experience with approximately 5,000 threshold pressure determinations. Our comments are directed primarily to the experimental procedures as described by Thomas et al. It should be noted that, while clay mineral-rich lithologies are the most common caprock materials, the samples used (Table 1) include low permeability sandstones and carbonates, but do not include shales or other formations in which clav minerals exert a dominant effect. While our experience on samples analogous to those investigated by the authors generally confirms their findings, we have found that even more rigorous experimental conditions must be imposed where clay minerals are the controlling factor. These additional conditions result from the well-known molecular character of the clay minerals themselves in which water is interlaminated with, and bonded to, silicate sheets, thus becoming an essential component of the molecule. In many clay minerals the character of the intersheet bonding, and thus the dimension of the lattice, is strongly affected by variations in the identity and concentration of cations present in the intersilicate water. On a supermolecular scale, adsorbed water films on particle or "flakes" of shale provide much of the cohesive force necessary to maintain mechanical strength. The thickness of these films is variable and inversely proportional to intergranular pressure within the dimensional limits involved in caprock investigation. The thickness of the intersilicate water layers may also be subject to pressure under some conditions. These considerations are reflected in several necessary modifications of the experimental procedures described by the authors. Two of these are, in our judgment and experience, of such importance that they cast real doubt on the validity of data obtained on argillaceous materials without their application. The very careful resaturation procedures proposed by the authors should give good results in connection with the relatively "inert" lithologies used in their experiments. Our experience suggests, however, that they would create more problems than they would eliminate if applied to argillaceous materials. 1. Drying of the sample at the temperature and for the duration indicated by the authors not only will dessicate the sample with consequent shrinkage cracking, parting along bedding planes, and even total disassociation in the case of fissile shales, but it may also alter the character of the clay minerals themselves — in some cases irreversibly. 2. Prolonged evacuation to 2 microns Hg further dessicates the sample and is even more effective in reducing the intersilicate water content. 3. Resaturation with water differing in pH or chemical content from that existing originally in the sample also serves to alter the nature of the sample, particularly its structure and strength. 4. Our experience has been that, even with the thorough precautions proposed by the authors, complete resaturation of very fine grained materials is rarely obtained. Yet our experience confirms the

Jan 1, 1969

By C. E. M. Meskers

End-of-life Electronic and Electrical Equipment, o_cially called WEEE, is unjustly regarded as mainly a waste management problem. What is structurally overlooked is the enormous resource impact of these devices. EEE rep- resents a tremendous metal resource, which should be uti- lized through e_ective recycling, which has a much lower environmental footprint than primary production. The actual amount of end-of-life EEE recycled today is embar- rassingly low since insu_cient EEE is collected and part of the collected EEE is exported to developing countries, where it is largely not entering o_cial recycling systems. To achieve a global recycling society issues like technol- ogy, economics, life cycle structure, stakeholder aware- ness and legislation have to be addressed in a global, co-operative manner so that sustainable closed product cycles can be obtained. Requirements for a "global re- cycling society" are de_ned to address today's reality of global ows of used consumer products, taking into ac- count the likely needs of the future.

Jan 1, 2009

By K. H. Hofer

La mecánica de rocas se basa en el descubrimiento de las leyes que siguen las perturbaciones del estado natural de la corteza terrestre provocadas por la actividad minera. En ese sentido, el presente texto señala la importancia de este proceso en la ciencia de la minería -en tanto revisa el comportamiento de la resistencia de la roca, determina el estado de las tensiones primarias de la corteza terrestre y analiza la repartición secundaria de tensiones provocadas por la formación de huecos y sus consecuencias sobre la roca en el espacio y tiempo.

Nov 1, 1971

By J. L. Kohler

This final report on Bureau of Mines Contract J0348005 presents the results of an investigation into the development of a Management Information System (MIS) for underground coal mines. The motivation for the research is the unrealized potential for increasing safety and productivity of the well developed mine monitoring system technology. The intent of this project was to examine the information issues, various design aspects of an integrated monitoring/MIS, and associated application concerns, such as the impact of this technology on safety. The work performed on this contract used mine ventilation as a prototypical example. The report is presented in five chapters and six appendices. In addition to the introduction and conclusions chapters, one chapter deals with ventilation MIS system requirements; another with the formulation of a knowledge-based expert system (KBES) structure to implement the integrated ventilation monitoring/MIS system, and one on the health and safety implications of the system. The appendices present details of the KBES system application with an example using a mine ventilation simulator (PSU/MVS). An important conclusion is that a KBES formulation of an integrated monitoring/ MIS for coal mine management is feasible and desirable.

Jan 1, 1986

By Y. F. Liang

Fe-6.5wt.%Si alloy has excellent soft magnetic properties compared with conventional silicon steel. It is very brittle at room temperature due to appearance of ordered phases, like B2 and DO3. In this paper, we investigate the effect of ordering on cold workability of this alloy. Methods of rapid quenching and hot rolling were utilized. It is found that rapid quenching and proper heat treatment of the hot rolled sheet could decrease the degree of order due to the very high solidification rate and high cooling rate. The rapid quenched sheet and hot rolled sheet after proper heat treatment could be cold rolled without crack. Microstructure, phase ordering, micro hardness, and cold rolling properties were investigated by Optical Microscope, X-ray Diffraction, Micro Hardness Indenter and Four-high Mill.

Jan 1, 2009

By R. Newman

An inexpensive slow-speed data acquisition system has been adapted to digitally record multiple parameters simultaneously at intervals of 15 seconds. The system was built for use with standard soils testing equipment to automatically record load and displacement parameters at predetermined instants in time. Simultaneous readout is achieved by the use of special signal conditioner and sample-and-hold circuits which read the multiple signals simultaneously and hold them until the slow acting system can print out. Three channels of a 10-channel system have been converted and found to operate successfully during a series of direct shear tests. A unique feature of the system, which significantly reduced its cost, is the power supply units. Dummy circuits are used to maintain a constant power demand during sampling) thus eliminating the need for a costly power supply with rapid response characteristics. The entire system, having an overall accuracy of 0.25 percent, was put in operation for a cost under $2,500.

Jan 1, 1970

By Jose P. T. Agapito

Several underground coal mines currently operating in the Beckley District of West Virginia are experiencing serious roof and floor problems. A significant portion of the estimated two billion tons of coal resources may be lost as a result of these ground control problems. Preliminary studies by the Bureau of Mines indicated that these problems are due in part to a high horizontal stress field. During this contract study, a field program was conducted to quantify the horizontal in situ stress. A total of 14 overcoring sites (using the Bureau of Mines strain-relief overcoring technique) in five mines were drilled producing 53 data sets. Analysis of the data was done to provide in situ horizontal stresses for each of the five mine, and for the district as a whole. Stress data indicate horizontal stresses far in excess of that predicted by theory and in some cases, up to six times the estimated vertical stress. In addition to the field testing, a detailed computer modeling study was conducted using finite element and boundary integral (displacement discontinuity) methods. Verification of in situ stresses was obtained by the models and analysis of various development geometries, mining methods and remedial techniques were conducted. Recommendations for reducing ground control problems and future studies are presented.

Jan 1, 1980

By Bali. D. D., S. Chattopadhyay

"The planning and construction of prime coking coal beneficiation plants in the nationalized mines in India are reviewed. Flow schemes, construction practice, materials consumption, and costs are detailed.Medium-capacity beneficiation plants with multiple loops are recommended under Indian conditions.IntroductionThe reserve of high-grade and easily washed metallurgical coal in India are quite limited. Prime coking coal constitutes approximately 22% of the total resources and occurs exclusively in the Jharia coalfield in the state of Bihar. Bharat Coking Coal Limited (a subsidiary of Coal India Limited (CIL) the nationalized mining sector of India) owns 80% of the Jharia collieries. The development of Jharia coalfield in the pre-nationalized period before 1971 has been characterized by a large number of small mines with primitive mining methods and low productivity. The production of prime coking coal to meet the demand of the steel industry in India has to increase from the existing level of 11.1 million tonnes to 43.4 million tonnes per annum by 2000 AD, thereby producing 5.61 million tonnes and 22.7 million tonnes of clean coal respectively. An ambitious program has been undertaken for development of bigger mines with an average production of 1 to 3 million tonnes per annum. With the fast dwindling reserves of good quality coking coal, more inferior grade coal seams, having difficult washing characteristics, are now being mined. All the coal from the future mines will have to be beneficiated to make it suitable for consumption of steel plants; the following washeries are being planned for construction by 2000 AD:"

Jan 1, 1986

By D G. Boxall

As an alternative to heavy water cooling, reactors cooled by organic liquids are being actively developed in Canada under the sponsorship of Atomic Energy of Canada Limited. One of the areas in which development has been required is that of core materials. The factors affecting the selection of fuel canning and coolant tube materials are discussed. It is shown that S.A.P. is a potentially attractive material for these applications. The fabrication of fuel sheathing is discussed. Difficulties met due to large inclusions and blistering due to high hydrogen contents have been overcome by magnetic separation and vacuum sintering of the powders. High-quality tubes can now be produced by extrusion to finished size. A study has been made of the mechanical properties of fuel-sheathing tubes and bar stock. The stress rupture properties of the tubes subjected to uniaxial and biaxial stress have been determined. The biaxial stress tests were performed by internal pressurization. For times in excess of about 200 hours, the curve of stress against time to rupture is extremely flat. The secondary creep rates of

Jan 1, 1965

By J. P. Jarrell

Environmental considerations are of increasing importance in determining the acceptability, schedule and cost of expansion ofCanada's uranium processing industry. Environmental considerations must be addressed in the early stages of facility planning. This results in a dilemma, as the process data needed to predict physical environmental impacts are not yet available from process design activities. Hence, a business risk is incurred if plant design is carried forward to meet these requirements prior to project (or site) approval. On the other hand, project scheduling normally mitigates against leaving process design engineering until such time as project approval is obtained. This paper examines the experience gained in Eldorado Nuclear's proposed expansion of refining capacity as viewed by an environmental engineering consultant. The history of the project and the relationship to process design functions in the two-year period prior to the Port Granby environmental hearings are reviewed. During the Port Granby public hearing, there was a consensus that normal operation of the proposed refinery could be successfully integrated with the site's natural environmental constraints. Moreover, the radiological impact from plant operations was demonstrated to be inconsequential. However, concerns were raised relating to plant upset and accident situations. These concerns are summarized. Process data requirements identified during the environmental hearings are discussed. Finally, the concerns for on-site burial of radioactive waste are reviewed. These concerns focussed on long-term stability of the waste in the presence ofgroundwater transport, erosion and glaciers. The AECB's position on waste management with regard to this project is reviewed in light ofthe implications for design.

Jan 1, 1979

By Dale Preece, Steven Sobolik, Richard Jensen

Recent events demonstrate that civil and government facilities and structures face an ever-increasing need to be designed for protection against malevolent explosions. Modification of existing public structures and especially design of new ones increasingly includes provisions for explosive protection. ISEE members endorse and promote responsible application of explosives to benefit mankind and deplore any other use. However, our knowledge of explosive behavior and our ability to predict the results of explosive events puts us in a unique position to give guidance to designers of civil and public structures. Recent advances in computational methods have resulted in new computer codes with ALE (arbitrary lagrangian eulerian) simulation capabilities. Historically, lagrangian computational methods have been used for modeling solids because the mesh or discretization moves with the material. Rock breakage resulting from explosively induced shock-waves has been successfully modeled with lagrangian codes. Explosive detonation has traditionally been modeled with eulerian techniques. Eulerian methods have been used to model gases and fluids, tracking the material as it moves through the computational grid. ALE computational technology couples the two methods together in a manner never before possible. An ALE simulation can accurately treat the explosive detonation, interaction of explosive gases with air, and the impact of explosive event on nearby solid structures. ALEGRA (Budge et al. 1997 a & b) is an ALE code developed at Sandia National Laboratories. ALEGRA simulations accurately predict the explosively induced impulse on the structure to be protected. It has been applied to the analysis and design of blastwalls to protect structures and people from explosive events. The impulse calculated can be used by structural engineers to design a blastwall. ALEGRA has also been applied to predict the effect of a blastwall on explosion overpressure some distance behind the blastwall to assess the effect on people present during the event.

Jan 1, 2000

By Benkendorff P. N

Cement production in Australia approximates 6.5 million tonnes per year. Cement clinker is sourced from 15 plants which operate 28 kilns. Cement grinding is conducted at 14 of the clinker plants plus 7 grinding plants. Average annual capacity per kiln or plant is lower than in many overseas countries, but kilns introduced since 1970's have been of larger size more in keeping with size trends overseas, although still smaller than the large units overseas. Substantial economies in capital and labour costs can be achieved in large production units, particularly with dry process kilns using precalcination techniques in which part of the fuel is introduced in the static preheater section ahead of the kiln while the balance is added to the kiln in a conventional manner. Precalcination techniques have been introduced to the Australian cement industry but as cement transport costs form a major part of supplying diverse market areas, the size of kilns is likely to remain less than maximum owing to balance with distribution costs. The cement industry uses significant amounts of thermal and electrical energy which can be minimised by proper selection of equipment and technology. Labour costs are also significant and can be contained by automation and computer control of the process.

Jan 1, 1989

By Kazuyuki Matsuzawa

A series of plate loading tests were carried out on a loam ground in order to investigate the influences of the plate size and the loading rate on the observed load-settlement relations. Two circular plates having diameters of 0.3 m and 1.0 m were used. Three types of loading methods were employed; 1) static cyclic maintained load test, 2) static continuous load test, and 3) rapid (dynamic) plate load test. An interpretation method called non-linear damping method was used to estimate a static load-settlement relation from the rapid plate load test signals. The derived static load-settlement relations match well with the measured results from the static load tests.

Jan 1, 2006

By Sheridan J. Rodgers

The quantity and behavior of gases in metal and nonmetal mines were monitored to provide background information on feasibility of incipient fire detection systems. Monitoring was conducted during working and nonworking periods at intake air, return air and working places. Gases generated during diesel operations and shot firing were of particular interest. Gases which were monitored were CU, C02, N0, N02 and S02: submicron particulate concentrations were monitored also. Commercially available instruments were used and included nondispersive infrared, electrochemical and chemiluminescent types. The ratios of the various gases generated during diesel operations and shot firing were similar to those expected from an incipient fire, with the exception of the C02/NOx ratio, which is sufficiently different to be considered for early fire warning. Samples taken near leaking bulkheads showed high C02 levels and low C0 levels, the reverse of anticipated behavior in coal mines.

Jan 1, 1976

By M. G. Wallis

This report presents the results of a study to develop a detailed mining method design based on longwall mining with sublevel caving. The method is applicable to low-dipping coal seams 20 or more feet thick such as are found in the western United States. The report covers (1) the development and description of the mining method, (2) evaluation of the engineering feasibility of the design, (3) estimates of productivity and recovery, and (4) an engineering cost analysis and economic feasibility evaluation of the mining method design.

Jan 1, 1977

By J. S. Dunning

One Federal Bureau of Mines research goal, to minimize requirements for domestically scarce mineral commodities through conservation and substitution, can be accomplished by utilizing more abundant elements such as iron, molybdenum, and titanium. An example of this research is the study of precipitation-hardening, iron-base alloys containing molybdenum and titanium, as substitutes for the high-tonnage stainless steels that are high in imported nickel and chromium. The precipitation hardened iron-base alloys are strengthened by a dispersion of the ternary Laves phase, Fe2 (Mo, Ti). Aluminum and chromium additions changed the solid solubility limits of molybdenum and titanium in a-iron and affected the composition of precipitating phases. A baseline composition of Fe-7Mo-2Ti was selected to study the effects of aluminum and chromium additions on the precipitation-hardening mechanism and microstructure and was also used in studies of mechanical properties and oxidation resistance. The study yielded workable, precipitation-hardening alloys, with elevated temperature strengths equivalent to or superior to types 304 and 316 stainless steels. Chromium and aluminum additions in combination were more effective in providing oxidation resistance than either addition was alone.

Jan 1, 1980

By R. A. Kearns

Biennially the Bureau of Mines issues a list of equipment that has been accepted as approved or permissible during the two calendar years immediately preceding the date of publication of the listing. By so doing the mining industry is kept informed of the availability of the latest equipment for safe use underground. This list supplements Bulletin 543, Permissible Mine Equipment Approved to January 1, 1953; Information Circular 7722, Permissible Mine Equipment Approved During the Calendar Years 1953-54; Information Circular 7840, Permissible Mine Equipment Approved During the Calendar Years 1955-56; and Information Circular 7957, Permissible Mine Equipment Approved During 1957-58. This list includes equipment meeting those standards that have been revised since Information Circular 7957 was .issued. Schedule 16E,4 a revision of Schedule 160, was approved May 19, 1960.

Jan 1, 1961

By Karsten Zimmermann

Surface deformation monitoring is required all over the mining industry. For example oil and gas companies need this information to support exploration and production activities and to detect impacts from surface subsidence of existing hydrocarbon fields. Also opencast mines require large area information of subsidence due to dewatering of the overburden. Because of this, a lot of surface deformations measurements with GPS or traditional geodetic measurement techniques have been conduced during the last decades. This paper presents the actual capabilities to analyze GPS data using the state of the art Bernese GPS Software for GPS post processing. A new way of monitoring subsidence is a combination of GPS and satellite InSAR data. Considering this it is hoped that a combined strategy will permit receiving overall more information by integrating high point density of InSAR and accuracy of GPS. DMT is one of the leading actors on GPS services especially for monitoring surface movements from underground activities e.g. mining, water pumping or oil and gas exploitation. The paper will discuss preferences and problems of this approach on results of a current project of DMT.

Jan 1, 2008

By J. P. Morris

The Bureau of Mines investigated the mechanics of fuming of iron-carbon melts during top-blowing with oxygen. Melts weighing 45 lb were prepared in an induction furnace and blown with oxygen by means of water-cooled lances. The rate of fuming was measured and correlated with the operating variables. The data showed that the primary cause of fuming was a boil at the bath surface in the impingement zone of the oxygen jet. Nucleation of the carbon monoxide bubbles producing the boil was apparently brought about by the precipitation of an oxide phase. The actual fuming mechanism involved partial oxidation and vaporization of bubble films and fine metal spray generated by the bursting of the bubbles. Bubbles that formed outside the impingement zone produced little fume. The distribution of trace elements between the metal and fume strongly indicated that the fume contained fine spray particles as well as particles that had condensed from vapor. The rate of fuming was found to be proportional to the carbon content of the metal) the concentration of oxygen in the jet) and the bath temperature) provided that a continuous boil occurred. In the absence of a boil) very little fume was produced.

Jan 1, 1967

By Zhou Wenbin

In this paper the mechanical properties of high carbon equivalent cast iron for automobile brake discs were analyzed through thermal analysis curves. Experiment results show that the mechanical properties have a strong correlation with thermal analysis curves and an effective way to predict the mechanical properties of high carbon equivalent cast iron was proposed based on the features of thermal analysis curves.

Jan 1, 2010