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"Power is transmitted to Butte, a distance of 130 miles, over two separate lines running parallel on the same right of way.The transmission line embodies the most approved ideas in construction. The conductors are No. O. B. & S. gauge, hard drawn copper strand. The insulators are of the suspension type, each insulator consisting of six units, 10 inches in diameter. The insulators will stand a wet test of over 300,000 volts, and were selected after long and careful tests by the company's engineers. The wires are carried on steel towers of four-legged, single crossarm type, manufactured by Milliken Bros. The three conductors are suspended in a horizontal row from the crossarm, and there are no transpositions in either line. Above the power wires and symmetrically located are two galvanized steel strands, Vs-inch in diameter, grounded at each tower, which serve as a protection against lightning.The distance between towers in level country is 600 feet. In mountainous country, however, the spans are irregular in length and spans of 1,500 or 2,000 feet are common. The longest one in the line is that crossing- the Missouri River and is equal to 3,034 feet. The length of this span is such that a person standing at one end of it can sec the wires go off and vanish into space, while the tower at the other end is barely visible to the naked eye on a clear day. The towers at one end of this span arc shown in the accompanying photograph. The line starts at an elevation of 3,200 feet, rises to an elevation of 8,200 feet as it crosses the Continental Divide, and again descends to 6,100 feet, the elevation at Butte.Quantity of coppc1· in transmission line, 1,330,000 pounds.Number of towers, 2,-1-00.Steel used in construction, approximately, 2,-1-00 tons."

Jan 1, 1913

By T. Iriyama, Y. Fujita, R. Omatsuzawa, T. Nishio, N. Okochi

Sm-Fe-N hard magnetic materials are good candidates for high performance bonded magnets. Rapid-quenching method should be highly favorable for the fabrication of isotropic magnet powder with high coercivity. We report here the magnetic properties of Sm-Fe-N powders produced by a few kinds of rapid-quenching processes. Sm2Fe17 powders were prepared by gas-atomization (GA), rotating-disk atomization (RDA), or melt-spinning (MS) method. The Sm2Fe17 GA powder had dendritic solidification structure, while the RDA powder had micro crystalline structure with size of 3-5 µm. Coercivities (HcI) of their nitrides were 56 (for GA) and 217 ka/m (for RDA). The H cI of nitrided Sm2Fe17 MS powder with wheel velocity (V5) of 5-20 m/s, which had also microcrystalline structure, was 53 to 509 Wm. These coercivity values are not sufficient for bonded magnet applications. From the study of additive effects, it was found that C, C-Si, C-Ga, or C-Al addition decreased the crystal size of quenched Sm2Fe17 powder. Consequently, high coercivity was obtained; the HcI of nitrided Sm2Fe1C1Si1 MS powder with V5 of 10 m/s was 898 kA/m, and 708 kA/m for the nitrided Sm2Fe15C1Si1 RDA powder. The compression-molded bonded magnet made from Sm2Fe18Si0.1Nx MS powder showed a high (BH)max of 82.7 kJ/m3.

Jan 1, 2000

By A Krishnan, C Garcia, I Luna-Berbesi

The discovery and exploration of deposits are progressively shifting to extremely remote regions and greater depths. As a result, exploration costs and the economic risk of a bad investment increase. Current megatrends in the exploration and mining sector indicate a growing demand for the implementation of automation, digitalisation, and machine learning techniques. The implementation of a multi-sensor-based core logging device (DMT, 2024) was done on 400 m of drill cores to optimise interdisciplinary processes in terms of time and quality, by using interlinked and consistent data in real-time, to obtain reliable predictions that support and speed up decision-making. The results are consistent with the laboratory data previously obtained by the mining company, highlighting the benefits of introducing ANCORELOG into their core logging procedures.

Sep 1, 2024

Hazardous waste has often very complicated chemical compositions in a variety of physical forms and is normally processed in rotary kiln incinerators. Due to large variations in waste types and difficulties in feed characterization, the complex transport processes within the incinerator are not well understood, and the incineration process meets challenges in a smooth operation, and expects various uncertainties in the process chemistry and emission control. For better understanding of the incineration process, simulation was carried out by using Computational Fluid-dynamics (CFD) to characterize temperature and species distribution in the incinerator. In order to catch certain aspects of thermal and chemical behavior, a novel approach is proposed to represent approximately the waste streams and the subsequent combustion process. Hazardous waste in various forms from an industrial-rotary-kiln waste incinerator is firstly converted to a hydrocarbon-based virtual fuel mixture with approximately the same HIC molar ratio and calorific value. The simulation of the combustion process of the simplified hazardous waste was proceeded with a combustion model. The distribution of temperature and chemical species especially the remaining CO in the system is preliminarily investigated. Distribution of CO concentration, as a good indicator of emission level for the incineration process, could be used to evaluate the emission control. The predicted temperature distribution has been compared with available measurement data from an operating rotary kiln waste incinerator at A VR-Chieme, in the Netherlands. Reasonable agreement has been reached between the measured and predicted temperature data. [n the next step, measurement of species distribution in the system is planned to further validate the combustion model.

Jan 1, 2003

By R. E. Hamilton

It is more than ten years since the first fully automated process using a computer started operation. Computer control has become common in a number of process industries, yet in spite of the tremendous incentives which ere present, there are only a few computer installations in the mining industry and none of these has announced successful control of a process. Recognizing that one of the reasons for this slow progress is the lack of adequate mathematical models of the various processes involved, the author's company started a project in the summer of 1966 to develop such models. It was early recognized that the existence of a major disturbance input, in the form of the mineral composition of the feed prevents most flotation plants from attaining a steady state condition. This makes the custom¬ary method of developing correlations from steady state plant data inapplicable and requires a more fundamental approach.

Jan 1, 1968

By Crook KAW

New sedimentological and biostratigraphic data indicate that the Leron Formation in the Markham Suture Zone, Papua New Guinea (PNG) represented Pleist- ocene alluvial fan-delta deposition in shallow marine to lacustrine environments. The distribution of sedimentary regimes in the Leron Formation indicates that during collision zone evolution, various tectono-sedimentary regimes do not always track the movement of the triple-junction systematically as idealized by Crook's (1989a) model. The migration of various tectono-sedimentary regimes are also controlled and influenced by the effects of second-order geometric features of the convergent margins. Leron Formation in the Markham Valley represents late to post-collisional marine to fluvial molasse. Foraminifera indicate that the collision and concomitant suturing of the Markham valley occurred after 1.32Ma.

Jan 1, 1991

By I. N. Zavarine

The present paper is a continuation of the work on the relationship between the magnetic and the phase transformations in carbon steels during quenching. An account was given by the author in a previous paperl† of an investigation of this relationship during a continuous quench. The experimental difficulties then encountered prevented a conclusive proof of the existence or absence of such a relationship. The conclusions of the previous paper were derived indirectly. The present paper deals with the same problem, but the method of attack is modified. The technique developed by Davenport and Bain2 in their well-known study of austenite transformation at subcritical temperature was adopted in the present investigation. They have shown that the austenite to martensite transformation can be caused to proceed at a relatively slow rate by quenching steels into a hot metal bath. Slowing down of the rate of transformation, together with an observation by Lewis3 that a eutectoid steel can be preserved in the nonmagnetic state by such quenching, pointed out a possibility of a study of both transformations under more favorable conditions than previously described. The preliminary steps were connected with the technique of the hot bath quench. To study this phase of the present work a modification of the apparatus previously described' was used. The modification consisted in the use of a hot quenching bath instead of brine, and in fixing the secondary and the primary coils of the apparatus in a stationary position in and around the bath. Tubular specimens, as in the previous investigation, were heated in a suitable furnace to a temperature in the austenitic range for the given steel and then were dropped into the quenching apparatus. The quenching bath was heated to a series of temperatures within the probable range at which the austenite to martensite transformation was expected to proceed at the slowest rate. Observations

Jan 1, 1936

By I. N. Zavarine

The present paper is a continuation of the work on the relationship between the magnetic and the phase transformations in carbon steels during quenching. An account was given by the author in a previous paperl† of an investigation of this relationship during a continuous quench. The experimental difficulties then encountered prevented a conclusive proof of the existence or absence of such a relationship. The conclusions of the previous paper were derived indirectly. The present paper deals with the same problem, but the method of attack is modified. The technique developed by Davenport and Bain2 in their well-known study of austenite transformation at subcritical temperature was adopted in the present investigation. They have shown that the austenite to martensite transformation can be caused to proceed at a relatively slow rate by quenching steels into a hot metal bath. Slowing down of the rate of transformation, together with an observation by Lewis3 that a eutectoid steel can be preserved in the nonmagnetic state by such quenching, pointed out a possibility of a study of both transformations under more favorable conditions than previously described. The preliminary steps were connected with the technique of the hot bath quench. To study this phase of the present work a modification of the apparatus previously described' was used. The modification consisted in the use of a hot quenching bath instead of brine, and in fixing the secondary and the primary coils of the apparatus in a stationary position in and around the bath. Tubular specimens, as in the previous investigation, were heated in a suitable furnace to a temperature in the austenitic range for the given steel and then were dropped into the quenching apparatus. The quenching bath was heated to a series of temperatures within the probable range at which the austenite to martensite transformation was expected to proceed at the slowest rate. Observations

Jan 1, 1936

By G. D. Tranter

The importance of ladle and teeming practice and its relationship to the yield and quality of the product has focused considerable attention on this phase of open-hearth operation. Inherently bad steel cannot be perfected by manipulation during teeming, but through the proper handling of "off heats" serious losses, which in many cases arise, can be greatly minimized. Conversely, good steel can be ruined as a result of poor workmanship in the pit, and rendered unsuitable for application to orders where exacting surface and physical requirements are essential. Sufficient evidence has been secured to warrant careful investigation of pit operations when an abnormal number of basic defects develop in the semifinished product or are found on the inspection table. This paper is written from the standpoint of the problems involved in making satisfactory ingots for sheet rolling. Furthermore, since rimming steel is almost universally used for manufacture of sheet, the data presented herein refer particularly to that type of steel. Going back some 30 years in open-hearth history, the word "pit" properly described the hole into which the ladle was lowered to receive the metal tapped from the furnace. The working space was necessarily limited, and the disposal of slag and metal overflowing the ladle or lost because of breakouts presented a serious problem. The equipment, of course, was rather crude in the light of present-day development. Often no ladle stands were provided, the ladle being hung on the crane beneath the runner. When delayed taps occurred, the ladle was often held in position for many hours, thus tying up pit operations and causing delays to adjacent furnaces. Because of crowded conditions, slag thimbles were not used and a network of cast-steel triangles and old tapping bars, placed before the heat was tapped, was the means for removing slag from the hole. Furnaces of different capacities were used

Jan 1, 1935

By G. D. Tranter

The importance of ladle and teeming practice and its relationship to the yield and quality of the product has focused considerable attention on this phase of open-hearth operation. Inherently bad steel cannot be perfected by manipulation during teeming, but through the proper handling of "off heats" serious losses, which in many cases arise, can be greatly minimized. Conversely, good steel can be ruined as a result of poor workmanship in the pit, and rendered unsuitable for application to orders where exacting surface and physical requirements are essential. Sufficient evidence has been secured to warrant careful investigation of pit operations when an abnormal number of basic defects develop in the semifinished product or are found on the inspection table. This paper is written from the standpoint of the problems involved in making satisfactory ingots for sheet rolling. Furthermore, since rimming steel is almost universally used for manufacture of sheet, the data presented herein refer particularly to that type of steel. Going back some 30 years in open-hearth history, the word "pit" properly described the hole into which the ladle was lowered to receive the metal tapped from the furnace. The working space was necessarily limited, and the disposal of slag and metal overflowing the ladle or lost because of breakouts presented a serious problem. The equipment, of course, was rather crude in the light of present-day development. Often no ladle stands were provided, the ladle being hung on the crane beneath the runner. When delayed taps occurred, the ladle was often held in position for many hours, thus tying up pit operations and causing delays to adjacent furnaces. Because of crowded conditions, slag thimbles were not used and a network of cast-steel triangles and old tapping bars, placed before the heat was tapped, was the means for removing slag from the hole. Furnaces of different capacities were used

Jan 1, 1935

William H. BLAUVELT, Anaconda, Mont.: Mr. Stetefeldt's comparison of the producer-plants at Aspen, Colorado, and Park City, Utah, is of special interest at this time, when the attention of all western metallurgists is so forcibly drawn to the necessity of reducing expenses and losses. The fact that wood was used at Park City before gas was introduced, for firing the Stetefeldt furnace and dryer, offered an excellent opportunity for showing the economies resulting from the adoption of gas in place of wood, as well as a comparison between the two gas-plants. Some time ago Mr. Stetefeldt contributed an article to one of the technical journals, in which the economy obtained by the substitution of gas for wood at this plant was shown quite in detail. I regret not being able to quote from his article at length, but, remember that the total saving effected would pay for the producer-plant in about one month. This is a striking instance of the advantages to be secured by the adoption of the best methods of using fuel in our metallurgical works. In comparing the figures from the Park City and Aspen plants, the difference of over 20 per cent. in the fuel used in the Stetefeldt furnaces, seems remarkable, even considering the larger amount of sulphur in the Aspen ore, and the greater rapidity with which it was roasted. It would be interesting to have Mr. Stetefeldt's, opinion as to the cause of so great a difference. The inferior economy of the revolving dryers at Park City might be overcome by lengthening them, or so arranging a second one above

Jan 1, 1894

By Andrew T. Zador

The growing demand for energy combined with the need to protect and preserve the environment have become prime considerations in the design of efficient coal handling ports and their associated stockpiles. The transportation system is analogous to a connected chain which originates at the mines and terminates at steel mills or power plants, in which the port and the stockpile reserves are a vital link. Railroad transportation costs can be minimized by rapid discharge of the cars which, in turn, requires that an adequate stockpile system be available. Ocean transport costs can be minimized by having an efficient high capacity ship loading system and sufficient quantities of coal on hand -all of which also requires an efficient stockpile system to meet shipping demands. The connector between the two modes of transportation, therefore, is the port stockyard. It is here at the interface that optimization of land utilization and materials handling equipment results in a total transportation chain that can operate as a smooth efficient system. Multiple origins of coal require the simultaneous handling of large quantities of coal of many grades. Railroad transportation logistics often limit and define the incoming arrival patterns and limited rolling stock often require priority treatment for railroad operations. The physical limitations of prime ocean frontage require that coal stockpiles be built close to residential or industrial areas which entail strict environmental controls. Large capacity, enclosed coal stockpiles for ocean shipping have not yet been considered feasible but may be forthcoming in the near future. Several have been analyzed.

Jan 1, 1978

By J. S. Pascover, S. V. Radcliffe

The structures and transformation temperatures of high-purity Fe-Cr alloys have been investigated as functions of composition (0 to 10 wt pct Cr) and rate of quenching from the high-temperature Y phase field (up to 40,000°C sec-1). The structures were chmacterized by transmission electron microscopy. The transformation temperatures for each alloy exhibited the progressive decrease to a constant value with increasing cooling rate which has been shown to be characteristic of several iron binary systems. The corresponding structures were found to become increasingly finer in scale with increasing cooling rate and solute content, but to remain essentially equiaxed in character. In all the materials except the high-purity iron and one of the alloys, an additional and lower transformation temperature than the constant value for the equiaxed structures was observed. The structures of specimens which transformed at these lower temperatures (only single thermal wrests were observed in any given run) were martensitic and consisted of arrays of fine ferrite laths which varied in size and morphology with changing solute content. The factors controlling the nature of these transformations are discussed. The composition dependence of the martensitic transformation temperature, ME, in Fe-Cr alloys together with those reported for other iron binary systems indicate that MB for pure iron is some 700°c, rather than the values of 550° and 760°C reported previously. This conclusion is further supported by the results of a compmison of the thermodynamics of mmtensite formation in several systems. ThE extensive investigations of the structures formed on athermal transformation in iron and its alloys have led to the characterization of several forms of martensitic or "military"1,2 transformations and, in addition, a "civilian7' transformation to ferrite or "equiaxed a"* which occurs athermally and at a very high rate.374

Jan 1, 1969

By AIME AIME

AT the Morenci branch of the Phelps Dodge Corporation, of which Frank Ayer is manager, several new types of machines that have been developed by Charles Mitchell, shop foreman in the drill steel shop, invite comment for their time and labor-saving qualities. Foremost of these is an adjustable gage-block and gaging device for attachment to drill-sharpening machines, developed and patent applied for by Mr. Mitchell. It replaces the blocks on the standard Ingersoll-Leyner drill steel sharpener No. 5. Features of the device are gage blocks with a flat surface which can readily be removed when worn and planed in any flat planer; blocks that can be adjusted with a templet to give a far more accurate gage than was formerly possible; and a center stop that is adjustable and can be accurately set to center any standard size drill steel.

Jan 1, 1930

By Flor De Cock

The paper reflects part of the work from the European Regional Technical Committee on Piles (ERTC3) during its mandate between 1994 and 1999, and, in particular, describes the find­ings from an International Seminar held in 1997 in Brussels on European practice for design­ing axially loaded piles. The seminar included contributions from 17 European countries, each of which provided a synopsis of their respective national design approaches. This paper pays particular attention to the design methods based on laboratory and in-situ test data for both bored and displacement piles.

Jan 1, 2002

By L. D. Hartzog

A pilot plant investigation of a semi-autogenous mill - ball mill circuit is described. The plant was operated with minus eight-inch diabase as feed material to the semi-autogenous mill. The semi-autogenous mill recycle screen underflow was put to a ball mill in closed circuit with a cyclone. An operating Work Index of 13.3 to 14.9 was obtained with the pilot ball mill. This Index is substantially in agreement with the scalped feed laboratory Work Index for 15.3 for recycle screen underflow. The Bond Index of the diabase was 15.8. Thus, one may use the scalped feed laboratory Work Index to size semi-autogenous grinding plant ball mills.

Jan 1, 1974

By S K. Schwank

Trench cutter systems have been used in civil engineering for the least 30 years for the installation of deep cut-off walls, retaining walls and foundation systems. The systems are constantly advanced to achieve greater depth, penetrate through harder rocks a provide a bigger footprint of the cutter. The state-of-the-art equipment can reach down to 250 m vertical depth and penetrate all different types of soils and rocks up to 150 MPa unconfined compressive strength.In mining, especially in commodities with a high value and where the ore deposit has a small footprint, cutter mining with vertical attack from the existing ground level will be a new, cost-efficient approach where conventional open pit mining is not economically feasible due to a high stripping ratio. The same applies for open pit mines that have reached the end of their conventional mine life and where going underground is also uneconomical. The BAUER Cutter Mining System, which has been adapted to the special needs of mining, is a new technology that will allow mining at depths of up to 250 m.The same system can be also applied to ore dykes, be it vertical or slightly inclined, concentrating the excavation on the actual orebody and minimising the strip ratio and the contamination of ore. The system can be adapted to the dimension of the dykes or veins and to the rock conditions.BAUER’s latest approach is to use the vertical cutter mining technology for the extraction of sea floor massive sulfides from the seabed in deep ocean waters. Due to the compact footprint of the system and the vertical attack for mining, extraction of the ore can be concentrated on the hot spots, minimising the environmental impact on the sea floor both for mining and manoeuvring the remote-controlled mining tool.CITATION:Schwank, S K, 2015. Cutter mining – crossover technology from civil engineering to mining, in Proceedings Third International Future Mining Conference, pp 95–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Laurance A. Beck

Safety is the most important aspect of haul road design. Although other aspects of road installation enter decisions on design, the safety of persons using the road has to be foremost for the duration of haul road usage. Other aspects of mad design focus on minimizing truck cycle time and fitting haul roads to the long-term configuration of the mine/quarry or construction project. Roads are often installed at high gradients for a short-term goal, but the long-term benefits are easily shown with lower gradient haul roads which provide better cycle times and lower operating costs.

Jan 1, 1995

By J L. Mauk

Gladstone Hill, a volcanic-hosted low-sulfidation epithermal prospect in the Coromandel Peninsula, is less than 1 km from the world-class Martha Hill Au-Ag deposit. Gold-silver-bearing quartz veins occur in Late Miocene andesitic volcanic rocks of the Waipupu Formation that are extensively altered. The occurrence, spatial distribution and temporal relationships of hydrothermal minerals have been determined along two cross sections that transect the Amaranth, Gladstone, Cowshed and Moonlight veins. Quartz and pyrite are ubiquitous along these sections. Adularia and chlorite are widespread, but both are scarce in wall rocks adjacent to the Moonlight and Cowshed veins. By contrast, rare hydrothermal albite and epidote are restricted to wall rocks surrounding the Amaranth vein. Illite, which replaces adularia, is widespread and grades laterally eastwards into a zone of interstratified illite-smectite that envelops the Moonlight and Cowshed veins. During late-stage hydrothermal activity, rare calcite formed at depth and uncommon kaolinite and alunite formed at shallow levels. The overall clay mineral zonation with illite grading eastward into interstratified illite-smectite reflects paleothermal gradients of >220¦C to -170¦C towards the margin. The alteration assemblage of quartz, adularia, chlorite, albite, epidote, illite, interstratified illite-smectite and pyrite reflects formation from a near-neutral to weakly alkaline pH chloride water that contained low concentrations of CO2, Late calcite formed from very local descending steam-heated CO2rich water, whereas the rare assemblage of kaolinite and alunite formed from shallow steam-heated acid-sulfate water. Analysis of the available data indicates that the Martha Hill deposit and the Gladstone Hill area formed within a single large geothermal system. We infer that the Martha Hill deposit formed in the main upflow zone, whereas the Gladstone Hill area may have formed adjacent to this upflow zone.

Jan 1, 2001

By P. T. Bissert, L. Yan, M. D. Klein

"Federal regulations require that refuge alternatives (RAs) are located within 305-m (1000-ft) of the working face and spaced at one-hour travel distances in the outby area in underground coal mines in the event that miners cannot escape during a disaster. The Mine Safety and Health Administration mandates that RAs provide safe shelter and livable conditions for a minimum of 96 hours while maintaining the apparent temperature (AT) below 35°C (95°F). The National Institute for Occupational Safety and Health used a validated thermal simulation model to examine the mechanisms of heat loss from the RA to the ambient mine and the effect of mine strata composition on the final internal dry bulb temperature (DBT) for mobile tent-type RAs. The results of these studies show that most of the heat loss from the RA to the ambient mine is due to radiation (51%) and conduction (31%). Three mine width/height configurations and three mine strata compositions were examined. The final DBT inside the RA after 96 hours varied less than 1°C (1.8°F) for the three mine width/height configurations and less than 2°C (3.6°F) for the three mine strata compositions. INTRODUCTION Following a mine disaster, workers will try to escape the mine. If their escape is futile, they can take shelter in a refuge alternative (RA). In 2008, the Mine Safety and Health Administration (MSHA) mandated RAs in mines to ensure that a safe and livable shelter is provided for a minimum of 96 hours, and that the apparent temperature (AT) does not exceed 35°C (95°F) inside the RA [1]. An ongoing concern with RAs is the potential to exceed this limit. The temperature rise inside an RA is due to the metabolic heat released by the occupants as well as heat released by the carbon dioxide scrubbing system. The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type training unit RA in its Safety Research Coal Mine (SRCM) to investigate heat buildup in RAs. The 10-person capacity for the tested RA is based on 1.4 m2 (15 ft2) of floor space per miner. NIOSH-developed simulated miners, which are heat input devices that generate both sensible and latent heat, were used to represent the metabolic heat generation of an average miner (117 W) for testing in the SRCM. It was found that the number of occupants in an RA may need to be reduced based on the ambient mine temperature, which varies from mine to mine [2]. To further research temperature rise inside an RA, ThermoAnalytics, Inc. (TAI) was contracted by NIOSH to perform thermal simulations of the tested 10-person mobile tent-type RA. TAI developed a thermal model of the SRCM using RadTherm software, which incorporates a human thermal model (HTM) to represent the equivalent metabolic heat loss of a miner within the RA’s enclosed environment. The thermal model was previously validated by comparing simulation results with test results [3]. During a mine disaster in which miners would have to take shelter in an RA, mine ventilation may not be available. As such, mine ventilation was off for both the testing in the SRCM as well as in the simulations. This paper discusses the heat loss mechanisms and the effects of mine strata composition and mine width and height associated with a ten-person tent-type RA."

Jan 1, 2016