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By Lorraine Brandt Yde

This paper describes development of a cost report that is descriptive, logically oriented, and concise. Since the costs involved relate to mining, this reporting technique could help bridge any possible communications gap between "mining men" and computer personnel, at the same time giving the computer-oriented mining individual information to assist him in his job performance. As computers become entrenched in the mining world, meaningful report assimilation becomes a major task. No one should be more capable of defining required results than the man requesting a report. If he is able to clearly state his needs and has researched his problem, it will be reflected in the computer output. During 1970, The Anaconda Company's Berkeley Pit Operation, at Butte, Montana, received many different computer-generated equipment cost reports. Up to thirty-six different components for each type (class) of pit equipment contributed cost data to the Berkeley Pit cost system files for both operating and repairs during current month, year-to-date and accumulation-to-date time periods. This reporting approach was taken to facilitate analyzing this voluminous data. SUMMARY A Major Component Cost Analysis (Exhibits 6-A thru 6-C) developed by arranging the top ten operating and repair percentages (component cost divided by total cost) in descending order, and then accumulating these percentages to a possible one-hundred percent. While tabulating the operating and repair cost percentages by equipment unit number in the current month, year-to-date and accumulation-to-date time periods, a frequency chart is constructed for each equipment

Jan 1, 1971

By E J. B van Etten

This paper reports on the results of several years of monitoring rehabilitation at a silica sand mine on the Swan Coastal Plain, south of Perth. Mining here occurs below the regional watertable and leaves a post-mine landscape of dredge pond voids (pit lakes) with surrounding battered slopes. The restoration we recommended was to develop the pit lakes as wetlands of regional analogue and value. Several different restoration techniques have been applied to re-vegetate pit lake slopes over many years which have enabled an evaluation of reasons for success/failure of different restoration approaches. Learning acquired clearly showed the benefits of using fresh topsoil for restoration over topsoil that has been stockpiled for several years. Most topsoil used in restoration was from seasonal wetlands and consequently restoration was most successful in the riparian zone from the edge of pit lakes to about 2 m vertically above the water table. Topsoil restored areas above this level remained poor in plant species and cover. Conversely, remedial seeding/planting proved largely unsuccessful. Permanently and seasonally flooded pit lake margins recolonised relatively quickly and successfully with native sedges and rushes. Development of rehabilitated upper slope plant communities over time was evident with loss of typical wetland species and greater growth and survivorship of upland and dampland plant species on mid to upper rehabilitated slopes. Plant communities of lower slopes showed a converse pattern of development, with a shift towards a more typical wetland composition. We believe matching topsoil to site and development of topographic profiles similar to natural wetlands of the region are the keys to optimising restoration success of sand mines with shallow water tables.

Oct 5, 2011

By Scott Rosenthal, Dave Gilkey, Theresa Stack, Daniel Autenrieth, Ciara Kremer

Jackleg drill operators are exposed to harmful levels of hand-arm vibration (HAV). Anti-vibration handles and gloves provide modest reductions in HAV exposures and forearm muscle exertion from the use of anti-vibration handles and gloves by jackleg drill operators. The goal of this pilot study was to investigate changes in HAV with the use of anti-vibration gloves and handles compared to forearm muscle exertion experienced by operators and measured with surface electromyography (EMG). Five subjects operated the drill under four different cases: no anti-vibration controls, anti-vibration gloves only, anti-vibration handle only, and simultaneous anti-vibration handle and glove use. Muscle exertion was expressed as a percent of maximum voluntary contraction (%MVC) and was compared using Welch’s ANOVA with Games-Howell post hoc comparisons. The case with both anti-vibration controls in use simultaneously (largest grip diameter) was associated with a mean %MVC of 36.13% during operation for all forearm muscles combined, which was significantly higher than that of the other cases (p < 0.05). There were no statistically significant differences in mean HAV exposures. The anti-vibration handle with anti-vibration glove case only increased the maximum allowable exposure time by 8 min as compared to the control case without any anti-vibration controls. These results suggest that the modest HAV exposure reductions from the use of anti-vibration handles and gloves may pale in comparison to the increased muscle exertion resulting from their use, and this trade-off among jackleg drill operators is a potential concern that warrants further investigation.

Jul 12, 2021

By C. W. Owings, L. D. Tracy

"IntroductionMany bituminous coal-mining companies have inaugurated extensive safety Programs, but the failure to have approved or permissible equipment or safe practice in only one part of a mine has resulted in disaster. The necessity of using only equipment bearing the U. S. Bureau of Mines approval plate is emphasized by the fact that many accidents are the direct result of carelessness on the part of trusted employees using non-permissible equipment. A concrete example is found in the case of an explosion on October 26, 1926, in a mine in the Pittsburgh district, Pennsylvania.Story of the ExplosionAt about 10 o'clock on the night of the explosion an examination was made in No 2 butt left and parallel off 7o. 14 north, and was found to be clear of dangerous accumulations of gas. (See figure). Several hours later a crew of two men brought a self-propelling rock-dusting machine within 50 feet of the face of Po. 2 butt parallel before they examined for gas. The machine operator found an accumulation of explosive gas about 18 inches from the roof. He began to wave his arms thoroughly mixing the gas and air. Undoubtedly a highly explosive mixture was created, and as the men attempted to run the machine back to fresh air an explosion occurred.The helper dropped to the floor and was burned about the face and wrists. The machine operator ran down the entry and was more severely burned about the face, neck, and arms. He later developed pneumonia and died. Both men reached the door in the chute between No. 14 and No. 15 north. A pumper, who had felt the rush of air, found the men and helped them to walk outside."

May 1, 1927

By R. HOLROYD

The Ludwigshafen and Oppau plants are largely independent I. G. factories situated some 23 miles apart on the west bank of the Rhine facing lannheim. The former factory is a general organic chemical works specializing in dyes, dye intermediates, plastics and synthetic rubber,. while the latter is a heavy organic chemical factory producing ammonia, methanol, higher alcohols and their derivatives. Before the war much of the I. G. research and development work was carried out at Ludwigs- hafen; in particular the high pressure research section directed by Dr. Mathias Pier played a very active part in all hydrogenation developments. Apart from the possibility that a full scale hydrogenation or Fischer Tropsch plant had been erected at Ludwigshafen/Oppau during the war, the main objectives of an oil team investigation were: - (a) To obtain from Dr. Pier and his staff an advance general picture of German fuel production processes. (b) To study the fuel developments still in the research and pilot plant stage. (c) To examine any new developments in hydrogen or synthesis gas manufacture. (d) To look for new processes for production of high anti-knock fuel constituents and for new fuel additives. (e) To investigate new chemical syntheses based on raw materials obtainable from oil. The Ludwigshafen and Oppau factories were first visited by the large team listed in Appendix A during the period 25-31st March. The investigation revealed that no large plant for synthetic fuels or lubricants had been operated at this target. All the important members of the Fuel Research Section staff had been evacuated to Heidelberg and information on the work of this department was therefore limited to that contained in seized documents, the greater part of which have still to be examined in detail. Valuable information on synthesis gas production from hydrocarbon gases was obtained as well as interesting data on a num- ber of chemical syntheses. Two members of the above team Holroyd and Faragher accompan- ied by Major Tilley (interrogator) went on to Heidelberg, contacted Dr. Pier and the chief members of his staff on April 1st and obtained from them the hydrogenation information given later in the body of the report. Later, after visiting Leuna, Holroyd, Faragher and Ellis paid a second visit to Heidelberg and to Ludwigshafen/Oppau on 27th-30th May to check a number of details, particularly with respect to hydrogenation costs, and to obtain information on the pressure.conversion of water gas to hydrogen and on the manufacture of Wickel pressure vessels.

Aug 1, 1943

By C. Dorfling, C. A. Snyders

South Africa has extensive mineral processing and extractive metallurgy capacity and infrastructure for metal production from natural resources. Decreasing ore grades, increasing labor costs, and more stringent legislation have made economic metal production from primary resources challenging. Opportunities exist for metal production from secondary resources such as mining wastes and end-of-life consumer goods. The objectives of this study were to evaluate the current status of metal production from secondary resources in South Africa and to identify potential opportunities for further development. Two main classes of secondary resources, namely mining waste and electronic waste, were considered. Primary metal producers are dominating metal production from mining wastes; several of the gold, platinum and chrome producers operate low risk and low cost tailings retreatment facilities that contribute significantly to their overall production. Further opportunities exist in, for example, the treatment of more than 450 estimated gold tailings dumps in Gauteng, as well as metal recovery from slags and furnace dust. The majority of companies involved with electronic waste recycling in South Africa focus on collecting and disassembling; only a few perform preliminary physical processing, with the recovered fractions then being sent overseas for metal recovery. Projections are that the rate of waste generation will increase significantly and that treatment will become critical to comply with more stringent environmental legislation. Projects related to process development, techno-economic evaluations and environmental impact studies for metal recovery from batteries, printed circuit boards, and fluorescent lamps are underway. South Africa is ideally positioned to further explore opportunities for synergistic relations between metal recyclers and primary metal producers. Processing of electronic waste for production of technology metals, for which limited natural resources exist in South Africa, would be a key enabler for local manufacturing industries and expansion of the value chain.

Jan 1, 2018

By Chris Lynagh, Collin Schroeder

Determining the best excavation method is a critical step in successful tunnel construction. In rock tunneling, several factors can dictate the excavation method, such as: (1) rock characteristics, (2) tunnel size and length, (3) nearby utilities/infrastructure, and (4) contractor’s preferred means and methods. This paper discusses the various rock tunnel excavation methods utilized on the Doan Valley Storage Tunnel Project (DVT), a project constructed as part of the broader Project Clean Lake in Cleveland, Ohio. The differences between each method’s initial and final lining, geology, and cycle sequence will be analyzed and compared.

Jun 13, 2023

By E. C. Harder

BAUXITE is known mainly as the ore from which aluminum is smelted but it has large use also in the manufacture of artificial abrasives and as a basis for certain chemical industries. A small amount is used for refractories and for other purposes. COMPOSITION Dana and others give the mineral formula of bauxite as A1203.2H20 and the composition as A12037 73.9 pct; H2O, 26.1 pct. It has been definitely shown, however, that bauxite does not exist as a specific mineral but rather as a rock. The term is now used synonymously with aluminum ore and it embraces gibbsite (hydrargillite or alpha trihydrate), A1203.3H20 (A12037 65.4 pct; H2O, 34.6 pct); boehmite (alpha mono¬hydrate), A1203.H20(Al203) 85 pct; H2O, 15 pct); diaspore (beta monohydrate), A1203.H2O(A12037 85 pct; H2O, 15 pct), and mixtures in various proportions of any two of them. Bauxite of the Mesozoic and Cenozoic in Europe is predominantly a mixture of gibbsite and boehmite, subordinately a mixture of boehmite and diaspore, or gibbsite and diaspore. The bauxite of North and South America, tropical Africa, Asia, and Australasia consists largely of gibbsite. Corundum (A1203) is not included under bauxite, although gradations from bauxite to emery or corundum exist. All bauxite, irrespective of the aluminum minerals composing it, contains certain impurities, including silica, in the form of clay minerals (kaolinite, halloysite, and others) or quartz, iron oxide (as hematite or goethite), titania (as leucoxene or rutile), iron sulphide (as pyrite or marcasite), iron carbonate (siderite), and calcium carbonate (as calcite); the last three mentioned in minor amount and of local occurrence only. Bauxite belongs to a group of partly consolidated materials called laterites, formed by surface weathering. This group includes also impure siliceous and ferruginous bauxite and siliceous and

Jan 1, 1949

By Susan M. White

Increased coal production, wider use of indiscriminate mining techniques, improved cleaning methods, and greater emphasis on clean fuels is increasing the rate at which wastes accumulate Over the next several years, Colorado Plateau underground coal production is predicted to increase. Currently, mine refuse is deposited in canyons or lowland areas near mines. This study presents information on the nature of coal refuse and disposal practices on the Colorado Plateau. Samples were collected and analyzed to provide information to help formulate alternative methods for reclaiming refuse piles. The analyses were based on determining the capability of unmodified refuse to provide a suitable medium for plant growth. Local topsoils which would be used in reclamation were used as standards. Potential environmental hazards were assessed also. A general cost analysis was done for both surface and underground disposal and the advantages and disadvantages of each were assessed. Several problems were identified which, if solved, would increase the effectiveness of state regulatory programs.

Jan 1, 1982

By J. K. Pandey, ebashish Mishra, D. P. Mishra, N. K. Mohalik, S. K. Ray

The increasing demand for coal and depletion of shallow depth reserves are pushing towards deeper mining. In deeper coal mines with multiseam workings, the problem of ventilation surges many folds primarily related to air quantity requirement, heat, humidity and spontaneous heating/fire in goaved (gobbed) out areas. The paper describes the design of a new approach to improve the ventilation system of a real-life deep underground coal mine with multiseam workings. For this, the ventilation problem of one deep underground coal mine 6&7 pits Bhutgoria Amalgamated Colliery of Tata Steel Ltd. with multiseam workings has been studied in detail to determine an appropriate solution. A ventilation survey of the mine and computer simulation of the ventilation network has been carried out to reach a practical solution. Ventilation survey results have been analysed to develop a representative ventilation network of the mine for both qualitative and quantitative analysis. Further, computer simulation of the ventilation network of the mine has been performed to virtually verify the application of a highcapacity booster fan in the present ventilation circuit without disturbing the vulnerable areas. Field validation is also carried out after the implementation of the solution in the mine to determine its efficacy. Thus, the findings of this paper can be directly applied for the installation of booster fans to achieve the required air quantity in deep underground coal mines with multiseam workings having spontaneous combustion liabilities of upper seam goaved out areas.

Jun 2, 2022

By R. Elliott, H. Bayati

"Effect of time and temperature on microstructure and mechanical properties of an austempered ductile iron, ADI, of composition 3.6%C, 2.6%Si, 0.4%Cu, 0.2%Mn are reported. Xray analysis and. microstructural observations indicate that lowering the working temperature, aging temperature, increases the lifetime of ADI significantly. Results show· that lowering the aging temperature increases the strength and reduces the ductility of ADI. DSC traces for ADI austempered at 340°C are presented. Comparison of the DSC analysis and kinetic measurements demonstrates that the DSC traces can be· used to predict the life time of ADI successfully.IntroductionAustempered ductile iron, ADI, is one of the most significant developments in cast iron technology over the past two decades. Outstanding properties of high yield, ultimate strength, ductility, fatigue and wear· resistance make ADI suitable for a range of applications including gears, connecting rods, crankshafts and agriculture machine components. The austempering reaction in cast iron occurs in two stages, Fig. I, in contrast to the single stage reaction in steel. In stage I the relatively low carbon austenite produced during austenitising transforms into ferritic plates and high carbon austenite, a metastable structure called·ausferrite. The high carbon ailstenite and supersaturated ferrite produced in stage I decompose into ferrite and carbide in stage II: to form a structure similar to the bainitic structure in steel. This behaviour exposes a well-defined processing window, t1 - t2, over which the maximum amount of ausferrite is produced, Figure 1. Whereas the bainitic structure determines the properties of austempered steel, ADI properties are mainly affected by volume fraction of retained austenite (VRA), austenite carbon content (ACC), unreacted or martensite volume fraction (UA V), compositiori and amount of carbides, and morphology of ferritic plates[l,2]. Due to the detrimental .effect of martensite and carbides on properties of ADI, an ideal structure of ADI consists only of ausferrite [l,2]. Thus, it is common to determine the processing window for each austempering treatment in order to identify the optimized austempering time. Decomposition of austenite (stage II) signals the end of the life time for an ADI component, therefore, the aging behaviour of ADI at different working conditions can be studied by determining the t2."

Jan 1, 2000

Jan 1, 1886

By F. M. Boler

The U.S. Bureau of Mines has configured a flexible data acquisition and analysis workstation, which incorporates control and analysis software written in-house for use in mining research experiments conducted in the laboratory and in operating underground mines. This data acquisition system combines computer-automated-measurement-and-control (CAMAC) modular instrumentation with a Unix-based graphics workstation. The data acquisition front-end hardware can be interfaced to almost any computer. CAMAC instrumentation modules adhere to mechanical, electrical, and digital interface standards and can be custom designed or purchased off the shelf. Communications along the CAMAC bus are regulated by the crate-controller module, which contains the only hardware link to the computer interface. Software support for the data acquisition and analysis workstation consists of a series of functions and programs written in the "C" programming language designed to provide flexible and fast data acquisition, processing, and analysis. The user can interactively control the digitizers and other CAMAC modules by sending standard CAMAC read, write, and command function codes from a menu-driven program. Automated data collection is achieved through software that responds to hardware interrupts triggered by acoustic emission or microseismic events. Graphics display routines are used to plot part or all of the data and provide the ability to process and store signal information selectively.

Jan 1, 1990

By Joan K. Kuenzi

This Information Circular brings together for consideration recommendations from U.S. Bureau of Mines research in the area of surface mine mobile equipment maintenance for the period 1982 through 1991. It updates the 1982 contract report by Baker and Alves that formed the basis for much of the work described in the present report. Recommendations for hazard abatement during work on mobile one equipment are presented and stem from the results and recommendations of the research in two areas: (1) equipment and workplace hazard reduction, and (2) management of maintenance information. Recommendations included in this report apply to both the operators and maintainers of mobile mining equipment as well as to the manufacturers of that equipment.

Jan 1, 1995

By André de Albuquerque Vicente

Foram estudadas três corridas comerciais de ferro fundido nodular. Para produção das corridas, partiu-se do mesmo metal base e utilizou-se a mesma liga nodularizante. Cada uma das corridas foi feita com inoculantes diferentes. Os percentuais em peso de inoculante e liga nodularizante foram, respectivamente, 1,0% e 1,3%. Estudou-se a nucleação e o crescimento dos nódulos de grafita. Várias técnicas complementares de análise microestrutural foram utilizadas, tais como microscopia óptica, microscopia eletrônica de varredura (MEV) e espectroscopia de raios-X por dispersão de energia (EDS). Observou-se a sequência de crescimento dos nódulos de grafita, evidenciando-se a formação de silicatos complexos ricos em alumínio, cálcio e bário ao redor dos núcleos, gerando uma interface favorável à solidificação heterogênea de grafita a partir destas partículas de tamanho superior ao raio crítico.

Aug 17, 2017

By Haitao Wang, Shen Wang, Dongyin Li, Yongjia Xu, Jinzhao Liu, Xiangjun Chen

The safe and efficient driving of the roadway along the gob is becoming an increasing challenge due to the influence of the integrity and bearing capacity of the side coal and rock mass in the gob under the roof cutting mining mode. The mechanism of protection of the gob-side roadway is shown by modeling the influence of roof cutting and the application of a destress technique on the lateral coal and rock mass zones. The distribution characteristics of stress, displacement, and fracture in the overburden are analyzed by numerical simulation method under the three working conditions. The results indicate (1) construction of row holes and blasting can form artificial structure’s fracture plane above the roadway, which can effectively cut the connection of overburden. The artificial structure’s fracture plane decreases the peak value of the lateral coal body’s support pressure. The peak point and the critical location of the stress reduction area are both transferred to the deep part at the same time, providing adequate space for the gob-side roadway. (2) The stress arch foot in the lateral rock mass rises to the rock layer at the bottom of the roof cutting plane after top cutting, as does the high-pressure area of deviator stress. The fracture plane prevents lateral coal and rock mass instability and limits the negative effects of roof deformation above the gob-side roadway. (3) The triangle slip fracture zone moves to over the roof cutting drilling zone due to the fracture plane, showing a high position compared to its original zone.

Jul 11, 2023

By Linn Bradley

Introduction MARKED differences of opinion have been expressed by engineers interested in cleaning iron blast-furnace gases for use in hot-blast stoves and under boilers, in reference to the advantages of a hot-dry method over a cold-wet method. One point at issue involves the sensible heat energy in the moisture contained in the gas. Some advocates of the cold-wet methods claim that the condensation and resultant removal of the greater portion of this contained moisture by wet scrubbing, spraying or similar methods, results in a saving of some of this sensible heat energy, by reason of the fact that water vapor has a high capacity for sensible heat energy and may carry from the exit of a hot-blast stove, for example, more heat units than are sacrificed or lost when the gas is cleaned by this cold-wet method. Other advantages claimed for the latter method are: That gas burns more readily when it is free from moisture in any form; that because gas is made denser by cooling and removing the moisture it has a higher calorific value than hot gas carrying moisture; and that higher flame temperatures are obtained when the gas is cleaned by the cold-wet method. A search through the available literature fails to disclose any extensive calculations or records of conditions obtained in practice, bearing upon these phases of gas cleaning. This paper deals with these problems from the standpoint of the economy of using a gas of higher flame temperatures, of improved stove design, and of economy in the gas-cleaning department. Calculations have been made which show that by cleaning the gases by a cold-wet method the sensible heat energy of the blast-furnace gases is greatly reduced; and, in general, this loss of heat energy is far greater than that lost from the stoves or boilers due to the sensible heat capacity of the water vapor if carried away by the exit gases. By making use of the

Jan 2, 1917

By M Muzammil, S. Mukerjee, S. Saran, M. Bharathi

"This paper presents the results of in-situ tests conducted on a set of under-reamed piles in a silty sand deposit. Three piles (i.e. vertical, vertical with one bulb and vertical with two bulbs) of diameter 0.2 m were cast upto a depth of 5 m. The pile cap had four foundation bolts cast into it so that a mechanical oscillatormotor assembly could be mounted centrally on it. The oscillator-motor assembly was used to generate purely sinusoidal dynamic forces, in either horizontal or vertical directions. For both horizontal and vertical vibration cases, it was observed that (i) the natural frequencies decreased with an increase in the excitation force level, (ii) for the same excitation level, the natural frequencies as well as the maximum amplitude of vibration are almost the same irrespective of the pile geometry i.e. number of bulbs in the pile, indicating that the full pile length is not being excited. For the vertical vibration case, the soil-pile stiffness at frequencies, before resonance, were observed to be higher than those at frequencies after resonance. In the horizontal vibration case, the stiffness of the soil-pile system was found to be decreasing with an increase in the excitation force level. The damping ratio was found to be increasing with an increase in the excitation force level.INTRODUCTIONUnder-reamed piles are piles, normally upto a depth of 6 m, with one or more bulbs along the pile stem. These have been used for structures like transmission towers, structures on expansive soils etc. for a very long time, however it is only in the last 30 years that dynamic response of a pile has been studied. Evaluation of dynamic soil-pile interaction is a very complex problem as the conditions and properties of soil are highly variable and unpredictable. Various models and approaches have been suggested by various investigators for evaluating the dynamic soil-pile interaction problem, but most of them are based on the assumptions that the behaviour of soil is linear and the soil surrounding the pile is strongly adhered to it. But in practice, it is not so. The soil surrounding the pile is always somewhat loosened and undergoes some deformation when a sinusoidal load is applied. This causes the soil-pile system to behave nonlinearly.In earlier studies by Novak, (1974), Novak and Aboul-Ella, (1978) etc. a linear elastic behaviour of soil was assumed. This approach was very useful in understanding the mechanism of soil-pile interaction to a large extent. Subsequently various models were suggested like the lumped mass models with nonlinear discrete springs, dashpots and friction elements Matlock et al. (1978), weak cylindrical zone around the pile model Novak and Sheta, (1980), ideal boundary zone model with non-reflective interface, Han and Sabin, (1995) etc. These approximate solutions give an idea about the mechanism of dynamic pile-soil interaction to a large extent. However, in reality both separation and slippage can occur due to the formation of a weak bond at the contact surface between the soil and the pile when a dynamic load is applied. In addition, the soil column adjacent to the pile experiences large deformations under dynamic loads and thus behaves nonlinearly.Some computer aided model studies on the dynamic response of under-reamed piles have been reported, however, very few insitu dynamic tests on under-reamed piles are reported. Dynamic tests on piles were carried out by Novak and Grigg (1976) on small scale single piles and pile groups in the field. Similar field tests on small scale piles were conducted to study the nonlinear behaviour of a single pile and a pile group under strong harmonic excitation by Han and Novak (1988), Han and Vaziri (1992), Burr et al. (1997), Manna and Baidya (2010) etc. The majority of these experimental studies were focussed on the response of the specific pile groups and compared with the results of a single pile. Hence there was a need to study the influence of pile g"

Jan 1, 2015

By Sharif Jahanshahi

Calcium ferrite slags are often associated with Professor Yazawa due to his pioneering work on the thermodynamics of this type of melts. Over the past years CSIRO has invested some effort in studying physico-chemical properties of such melts to fill in some gaps in our knowledge and explore opportunities for application of the understanding developed. These investigations cover thermodynamics, transport properties of calcium ferrite based slags, as well as the kinetics of reactions of such slags with refractories. The present paper provides an overview of some of these studies and highlights some of the interesting behavior of such melts, The oxidation state of copper and arsenic in calcium ferrite based slags are predominantly Cu+ and As3+, respectively, at oxygen potentials below 10-7 atm. The concentration of CU2+ in such slags becomes significant at oxygen potentials of greater than 10-7 atm at 1300 °C. The activities of CuO0.5 and AsO1.5 in calcium ferrite slags show strong deviations from the Raoultian Law, while that of CoO is very close to ideal behaviour with respect to pure solid CoO. Addition of SiO2 to calcium ferrite slags can have significant effects on the activities of FeO and Fe2O3 and hence the stability of magnetite phase. Transfer of oxygen in calcium ferrite slags is fast with diffusivity of 2x 103 cm2/s at 1350 °C and activation energy of 16 kcal/mol. Presence of solid phases, such as magnetite, has pronounced effect on the viscosity of calcium ferrite slags. The observed dependence on solid loading and shear rate indicates deviation from Newtonian behaviour. The interfacial tension between copper mattes and calcium ferrite slags is strongly dependent on the matte grade, with the determined values being much lower than the corresponding ones for interfacial tension between similar mattes and iron silicate slags. MgO, Cr2O3 and MgCr2O4 have low solubility in calcium ferrite slags and their solubility increases with increasing copper oxide content of the slag at 1300°C. The oxidation state of the slag has strong effects on phase transformation, dissolution rate and disintegration of refractories in calcium ferrite slags. Other key factors with major impact on slag-refractory interactions include viscosity and surface tension of slags as well as the contact angle between slag and refractory material,

Jan 1, 2003

By Robert Bachus, Nikolaos Machairasm, Allen Cadden

Data Interchange for Geotechnical and Geoenvironmental Specialists (DIGGS) is a data transfer standard that is gaining widespread acceptance in the geotechnical and geoenvironmental communities. Originally developed using funding from the Federal Highway Administration (FHWA) to efficiently capture data related to geotechnical boring logs, cone penetration test (CPT) soundings, and lab testing results, the data transfer protocol is rapidly gaining traction. It has been shown to have beneficial impacts in other allied areas where disparate parties (i.e., consultants, contractors, vendors, etc.) routinely publish/submit data as part of project deliverables. The historic problem is that many of these submissions use paper copies (i.e., .pdf images) to transmit valuable data for the project… data that may extend beyond the “technical” aspects of the project (e.g., equipment operating conditions, construction production rates, project costs, etc.). These data could be used by multiple parties to assess project performance and safety, as well as to track productivity, etc. Currently, in the limited situations when actual data are compiled and transmitted, the data often are submitted as an author-specific (and often proprietary) software application and must then be re-entered into other software applications (e.g., analysis software, database, etc.) for use beyond simple data collection. An initiative undertaken by the Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE) focuses on exploiting the full potential of DIGGS to geoprofessionals both within and outside of the transportation community. The deep foundations industry represents one community that could benefit significantly from using DIGGS. Data of interest to DFI members include production records, quality assurance information (e.g., verticality and alignment, concrete strength), and, importantly, load test results. When adopting DIGGS, users need not modify how they capture data, but rather will use DIGGS as a vehicle to transfer data to other applications in a standard format where it can be shared, used, stored, and retrieved. This paper and associated presentation will describe DIGGS and demonstrate how DIGGS can be used effectively within the deep foundations community.

Jan 1, 2019