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By H. I. Aaronson

THE TTT-curve for the beginning of transformation in hypoeutectoid steels containing appreciable amounts of relatively strong carbide-forming alloying elements often exhibits a "bay" at intermediate temperatures. In many of these steels, proeutectoid ferrite is the initial product of the decomposition of austenite not only at temperatures above the bay but also in an appreciable temperature range below the region of the bay. Hultgren has postulated that ferrite formed above the bay, termed "orthoferrite", contains the equilibrium concentration of alloying element at temperatures above the eutectoid range, and the extrapolated metastable equilibrium concentration at lower temperatures. The ferrite formed below the bay, on the other hand, termed "paraferrite", was assumed to inherit completely the bulk alloy content of the austenite without regard for the compositional requirements of equilibrium. As shown schematically in Fig. 1, the two types of ferrite were taken to have different Ae3 temperatures and different C-curves on a TTT-diagram. Their different kinetic behaviors were thus considered responsible for the bay in the TTT-curve for the proeutectoid ferrite reaction in this type of alloy steel.

Jan 1, 1962

By Alexander Pomerantsev

In recent years, bucketwheel excavators have found wide application in open pit surface mining not only because of their large production capacities, but also because they easily lend themselves to automation. Krupp, Orenstein & Koppel, Buckau-Wolf, Mechanical Excavator, Lauchhammer, Manufacturers in Eastern Europe designed and installed many models of bucketwheel excavators that can excavate any type of materials, could be used in any climate conditions and for any type of technological schemes in open pit surface mining, (Photo I, II and III)

Jan 1, 1979

By J. W. Rutter, K. T. Aust

The temperature dependence of the rate of grain boundary migration was measured in bicrystals of zone-refined lead containing from 20 to less than 1 ppm by wezght of tin. The apparent activation energy in the temperature range from 320" to 200oC is markedly dependent upon the solute tin concentration and upon the orientation relationship of the grains adjacent to the grain boundavy. The quantitative experimental observat~ons are compared with the predictions of various theories of grain boundary migration. In previous work.&apos;?&apos; the mobility of individual grain boundaries was studied as a function of impurity concentration and type of boundary. Grain boundary migration occurred at the expense of dislocation arrays which were introduced into the specimen during solidification. Boundary mobility in zone-refined lead at 300°C was markedly decreased by small additions of tin. 0.004 wt pct being sufficient to decrease the rate of grain boundary migration by a factor of 1000. The mobility of grain boundaries having polar orientation relationships near 38 and 22 deg about <Ill>, and 28 deg about <100>, was much less sensitive to tin concentration in the range studied. As a result, these boundaries have relatively high mobilities. The present paper is a continuation of the above study. Data are now presented on the temperature dependence of the motion of individual grain boundaries in zone-refined lead as a function of solute tin concentration and orientation relationship of adjacent grains at the grain boundary. The experimental observations are compared with the predictions of a number of theories of grain boundary migration3-8 which, prior to the present experimental investigation, could not be critically evaluated. EXPERIMENTAL PROCEDURE The striation or lineage structure of melt-grown single crystals of zone-refined lead, containing various additions of tin, was utilized to provide a driving force for grain boundary migration, as previously described.1,2 Each grain boundary under study separated the striated single crystal from another grain which was introduced by localized plastic deformation and recrystallization of a small region of the sample. The speed of migration of grain boundaries in dilute alloys of tin in zone-refined lead was investigated as a function of 1) tin concentration from < 0.0001 to 0.002 wt pct, 2) temperature in the range of 200" to 320°C, and 3) orientation relationship of the adjacent grains at the grain boundary. The substructure driving energy available for grain boundary migration was estimated to be about 4000 ergs per cu cm, within a factor of two, from specimen to specimen.&apos; The specimen dimensions, and growth and alloying procedures for the preparation of striated single crystals of lead of known tin composition, were as described previously.&apos; Each bicrystal was carefully wrapped in aluminum foil, and annealed in a well-stirred salt bath consisting of 50 pct NaNO2 and 50 pct KNO3, for known periods of time at a series of constant temperatures (*2°C). The grain boundary positions, before and after each anneal, were determined by etching lightly in a solution of 5 pct nitric acid in methyl alcohol, in order to follow the motion of the boundary and determine its rate of migration. Thus, the rate of motion of the grain boundary in a single specimen was measured at various temperatures. The above procedure was carried out for each grain boundary in seventeen different bicrystal specimens.

Jan 1, 1960

By Bill Paparis

The thirty year old wharf structures at the Port Authority of New York & New Jersey?s Port Elizabeth Marine Terminal are being modernized for the next generation of Post-Panamax container ships, which require deeper water and larger container cranes. The terminal operator is upgrading the wharf in order to remain competitive, now and into the future. The upgrade coincides with the Army Corps of Engineers? $733 million project to deepen the main shipping channel in New York Harbor. This paper focuses on the structural modifications to accommodate berth deepening and to support the heavier loads of the new cranes. An overview is provided of the design and actual construction, including typical problems encountered when combining new and existing structures. The wharf improvements included: ? Installation of a steel king pile/sheet pile cutoff wall along the face of the wharf to permit increasing the depth from ?12.2 m + 0.61 m to ?15.2 m + 0.61 m ( ?40 ft + 2 ft to ?50 ft + 2 ft) ? Removal of the existing crane rail support beams and installation of new piles and beams to support the increased crane loads ? Replacement of the existing timber fender system with a new system capable of resisting the berthing energy of a 152,000 MT displacement vessel, and having dedicated sections for berthing barges ? Replacing the existing overhead, landside crane electric feeder system with a waterside, cable reel trench system. The work included upgrading the transformer capacity at the terminal for increased crane power demands This paper provides a case history for port administrators, terminal operators, engineers, and shipping lines challenged with upgrading aging terminals.

Jan 1, 2013

By Toyohiko Hirota, Fukuo Itoh

Oil and natural gas aside, sea floor mineral resources currently being exploited in Japan are offshore sand and gravel and deep-sea manganese nodules. The mining of sand and gravel has already started. With regard to manganese nodules, the geophysical investigation and the study of the mining method are also underway. This report outlines the activity of a few Japanese firms, the Deep Ocean Minerals Association formed by some 30 private firms, Government agencies, a public corporation and two government research institutes. Researches on new exploration instruments, properties of deep-sea sediments and the mining method currently conducted by the National Research Institute for Pollution and Resources are described in detail.

Jan 1, 1976

A number of suggestions have been made to improve the design of cells used for electro winning and electro refining of metals. Most of these designs have been aimed at increasing the current density used in order to improve cell capacity, although the purpose of some has been to produce electro deposited metals in a continuous manner. Improvements in the electrolyte flow pattern in conventional cells have resulted in an increase in the rate of mass transport of metal ions to the electrode surface; giving rise to lower concentrat- ion polarization and an improvement in the nature of the product obtained, Other cell designs are based on a moving electrode, usually a rotating disk, and these may include provision for removal of the product in a continuous manner, The maximum current density which can be used in an electro- lytic deposition process is determined by the limiting diffusion current, the physical nature of the, product, the purity of the product required and by the increase in power costs which result from the higher cell voltages, This paper examines the properties of an agitated bed of particles as an electrode system when used for a metal deposition Process,

Jan 1, 1969

By George Straghan, Ralph Thomas

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By Ralph Thomas, George Straghan

OIL production in Kentucky in 1941 was 5,191,024 bbl., one barrel less than in the preceding year. The total completions for the state numbered 714, of which 256 were gas Manuscript received at the office of the Institute Feb. 26. 1942. * Geologist, .Kentucky Weal Virginia Gas Co., Ashland, Ky. † Geoloneist. Inland Gas Co.. Ashland. Kv. producers, 220 oil wells, and 227 dry holes. The total number was 95 more than in 1940. No new important oil or gas pools were discovered. The number of dry tests was large, although many of the dry holes could be considered wildcat tests. In western Kentucky, 365 wells were drilled, of which 145 were oil producers,

Jan 1, 1942

By C Placzek, E Beattie, K Blake

Channel iron deposits (CID) consist of ferruginous chemical sediments, and are an unusual subset of Phanerozoic ooidal ironstone deposits almost unique to the Pilbara, where they constitute around 19 per cent of the Pilbara’s iron ore exports. These deposits occupy many of the ancestral river channels of the Pilbara region, especially the Robe River palaeochannels, incising and meandering through the Precambrian banded iron formations (BIF) of the Hamersley Group and the underlying Fortescue Volcanics.This paper explores the factors underlying geochemical variation in CID, particularly the chemical properties of goethite. The selected deposits in the western Robe palaeochannel and its tributaries show little or no secondary reworking by later water tables. There is a total absence of aluminosilicate clays with all the deleterious elements such as aluminium and silica. Instead, these are associated with the goethite mineral lattice, either within or adsorbed to the cortices of pelletoids.A thickly vegetated environment, and the presence of the Maddina Volcanics as potential source rocks for these western Robe CID is offered as an explanation for relatively high aluminium in the deposits studied, and, in turn, as the reason most parts of the palaeochannel are preserved as inverted topography.CITATION:Beattie, E, Placzek, C and Blake, K, 2017. Dirty goethite – a geochemical characterisation of some western Robe River channel iron deposits, in Proceedings Iron Ore 2017, pp 489–502 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Hongbo Zhao, Jun Wang, Wenqing Qin, Guanzhou Qiu

Jan 1, 2015

By Jack R. Dymond, Ronald G. Senechal, Robert O. Rye, Cyrus W. Field, Joseph F. Whelan

Metalliferous sediments are present through- out much of the ocean basins and are locally prominent in the sedimentary column on and near the Nazca plate of the east-southeast Pacific Ocean. They typically have anomalously high concentrations of the transition metals, and those on parts of the East Pacific Rise, the Bauer Deep, and other basinal depressions may contain more then 12% iron, 4% manganese, 0.1 % each of copper and nickel, and geochemically significant amounts of zinc, cobalt, molybdenum, arsenic, beryllium, silver, and possibly gold. Statistical interprerarions of chemical data indicate that most metals in sediments on the East Pacific Rise were derived from a hydrothermal component related to submarine volcanism, whereas those in basinal sediments accumulated from both hydrothermal and hydrogenous components of sedimentation. However, concentrations of the metals are controlled more by the absence of biogenic and detrital components than by nearness to centers of hydrothermal activity.

Jan 1, 1983

By John O. Atkins

[Experiments were conducted by the Bureau of Mines on five types of simuated lunar rock (dacite, tholeiitic basalt, vesicular basalt, pumice, and uluth Gabbro) to study the effects of various simulated lunar environments n their strength and deformational properties. Specimens were tested in an ltrahigh vacuum (UHV) system at pressures ranging from atmospheric down to 0-11 torr and at temperatures of -130°, 20°, and 135° C. All tests were onducted with a servocontrolled testing machine. Rock specimens tested at 0° C in UHV exhibited significantly higher compressive strength and Young&apos;s odulus than those tested at 20° C in atmospheric pressure. The magnitudes f increase are related to the porosities and permeabilities of the rock pecimens; high porosity and permeability allow better outgassing and thus nprove surface cleanliness in UHV. The compressive strength generally ncreases but Young&apos;s modulus decreases as test environments change from 20° C i UHV to 135° C in UHV. No significant difference was observed in the iysical properties measured at 20° C in LTV and -130° C in UHV. Anisotropy i strength and Young&apos;s modulus exist both in UHV and at atmospheric condi¬&apos;.ons with the same symmetry pattern. The orientations of the principal axes iy, however, change from the atmospheric to UHV condition. The results idicate that rock fragmentation in lunar environment will require more ergy than that at 20° C in atomospheric pressure.]

Jan 1, 1974

By R. J. Dippenaar, W. H. Van Niekerk

"An injectable lime-based desulphurization reagent for the treatment of liquid iron was developed. Firstly, selected lime based slags containing small quantities of CaF2 to increase fluidity, and Na20 to increase the basicity, have been evaluated on laboratory scale from a thermodynamic point of view. Subsequently, pilot plant and full scale industrial injection trials were conducted. It was found that lime-based slags, containing Na20 and CaF2, are able to desulphurize liquid iron efficiently. By the injection of a lime based reagent consisting of 60% lime, 25% soda ash and 15% fluorspar at a rate of 7 kg reagent/ton hot metal, the sulphur level in the metal (115kg) was reduced from 0,07% to 0,01 % within 5 minutes. The lime-based reagent developed in this study was successfully injected, both from a metallurgical and from a pneumatic point of view, on an industrial scale. The mathematical model utilised in this study, can be used successfully to predict the course and extent of desulphurization by lime-based slags. IntroductionMainly due to environmental difficulties encountered with pure soda ash, dry slag formation with CaC2 and high cost when Mg are used as desulphurizers, much incentive exists for the development of an inexpensive, environmentally friendlier desulphurization reagent. As a first step in the development of such a reagent, selected lime based slags containing small quantities of CaF2 to increase fluidity, and Na2O to increase the basicity, have been evaluated on laboratory scale from a thermodynamic point of view. This was followed by pilot plant injection experiments in which the kinetics of the relevant desulphurization reactions were evaluated. Finally, full scale industrial trials were conducted. All three phases of the investigation will be discussed with the major emphasis being placed on the kinetic study."

Jan 1, 1996

By W. E. Horst

Historically, research organizations have made significant contributions to the development and commercialization of new chemical products for the mining industry and examples of commercial results are cited With the recent demise of research organizations within the mining industry and dynamic changes in the industry, the supporting role of R&D groups has become limited or non-existent. Cat- reduction requirements and new raw-material sources offer future opportunities for R&D organizations to continue their effective participation in the commerical development of new chemical products. Potential areas of interest for future process applications are reviewed.

Jan 1, 1986

By T. Eger

Load Haul Dump vehicles (LHD) are extensively used in underground mining however equipment design and operating conditions contribute to restricted operator?s visibility. The inability to clearly see people, objects or hazards around the machine has contributed to a number of accidents including fatal injuries. In order to identify vehicle design characteristics resulting in restricted and blocked sightlines visibility assessments are traditionally completed in the field. However, field methods are unable to evaluate visibility under dynamic operating conditions and are limited in their ability to provide feedback on the impact of various operator characteristics such as sitting height, for example. Results of this research show computer simulation and virtual reality can be successfully used to evaluate visibility during the operation of LHD vehicles. In order to benefit from virtual reality applications the work environment, LHD vehicle and human posture need to be represented as accurately as possible. A computer simulation program with ergonomic ana lysis features, Classic JACK 3.1, was successfully used. Threedimensional CAD models of LHD vehicles were developed from manufacturer specifications and pictur es taken from LHD vehicles currently in use. The LHD models were imported into the JACK environment, a digital human was positioned in the cab of the LHD vehicle and the vehicle and human where driven over a typical mine route. Real-time feedback in the JACK program was used to identify what the operator could see under different operating conditions. Machine characteristics and operating scenarios resulting in impaired visibility were successfully identified with this method. The JACK program can also provide real-time feedback on the human?s joint forces and torques, strength requirements, postural comfort, and metabolic energy expenditure. As a result, this method could be used to successfully evaluate musculoskeletal injury risk factors along with system design recommendations to improve workplace safety and productivity in any setting. The LHD VRML files imported into JACK have also been combined with environment files into other VR software packages (e.g. Maverik) to view in a VRL facility, managed by MIRARCO at Laurentian University. The VR models using these packages can be viewed in stereo to provide better appreciation of spatial visibility issues.

May 1, 2003

By Goodheart B

The Australian Mineral Sands Industry has expanded from the initial export of mixed concentrates in the 1930s, through various development stages, to its current position as a leading world producer of individual mineral products and some further processed products. Opportunities for downstream processing of the separated minerals and locating such developments in Western Australia are reviewed, along with the role of the Western Australian Government in assisting resource development projects.

Jan 1, 1986

By Del Brock, Dan Wooton

The design/build of two adjacent vertical mine shafts in difficult ground conditions at a mining complex in the midwestern United States required innovative construction techniques. Construction of the 267-m-deep Service Shaft required full depth dewatering wells and ground freezing. Blind drilling was utilized to excavate the 257-m-deep Production Shaft and it was finished with a steel/concrete composite liner that was floated into place. An equally unique component of the installation included supplying a high capacity vertical conveyor system, featuring a 273-m-lift. Other components of the project include the mine level development, as well as the design and installation of three hoisting systems, including a 45-ton capacity men/materials hoisting system.

Jan 1, 2003

By R. B. Haagensen, E. Martinez, V. Kudryk

The sample under investigation contained approximately 16% BaSO, and was 80% -325 mesh. Established methods for floating barite did not produce concentrates of satisfactory grade or barite recovery because of low barite content and the presence of 6% calcite in the feed. By using a new long-chain sulfosuccinamate collector in combination with relatively high concentrations of sodium silicate, a barite concentrate was produced that would be acceptable as an oil-drilling mud using a simple rougher-cleaner circuit. No desliming of the fine-ground feed was necessary. Barite recovery was over 80% and the concentrate produced had a specific gravity higher than 4.3. During the course of the investigation, a procedure was developed to obtain semiquantitative determinations of barite, calcite, quartz, and feldspar in test samples using an infrared spectrophotometer. Samples were also analyzed in a thermobalance for determination of the calcite content. The use of these instruments made it possible to obtain quick mineralogical assays and proved to be of invaluable assistance in guiding the flotation testing.

Jan 1, 1976

By Gustavo Herrera Rico

As part of a general effort to increase safety, efficiency, and profitability of its mining operations, MICARE personnel with the support of NorWest Mine Services, Inc. determined that the key to improving development mining was the implementation of roof bolting as the means of primary roof support for both main entry and longwall gate road development. Until mid-1994, MICARE had relied exclusively upon primary roof support systems composed of heavy steel beams and wooden posts. Support systems were designed, implemented, and evaluated that were successful in controlling the mine roof under extreme geological conditions. This paper describes the geological challenges, support selection criteria, and presents the instrumentation and &apos;mine measurements made to assess the bolting performance during the development and retreat mining process of longwall mining.

Jan 1, 1997

By Ernest Naesgaard

Post-grouted micro-piles were used for the seismic upgrading of the Vancouver International Airport Domestic Terminal Building (DTB). The micro-piles provided vertical resistance to both uplift and compression loads to supplement the existing timber pile foundations ability to resist the earthquake induced forces, and to provide foundation support at locations where the installation of traditional driven piles was difficult. This paper describes the site conditions, design rationale, installation method and quality control testing procedures. Site and Subsurface Conditions Vancouver International Airport is located within the central portion of Sea Island, Richmond, British Columbia (Fig. 1). Sea Island is bordered by branches of the Fraser River on the northeast and south sides and the Strait of Georgia along the west side. The natural grade of the island is part of a large delta that has been built up over several thousand years. The general pattern of sediment deposition has followed the direction of the Fraser River flow from east to west, and has built up soft sediments of about 200 m thickness at Sea Island (Luternauer, et al. 1993, Mathews and Shepard 1962). The original grade in 1962 prior to the existing Airport Terminal Building development was at about geodetic elevation 1.1 m with a grass and topsoil cover.

Jan 1, 2004