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By Donald Babbitt

In 1971, during the planning and design stages of a $300 million expansion, the Iron Ore Company of Canada Ltd. through its Engineers, Canadian Bechtel Ltd., came out with a preliminary request for two (2) 10,000 LTPH belt conveyor scale systems. These Systems were to provide weighing accuracies within 2.5% of the iron ore pellets and concentrates in transit on two (2) 72" wide conveyors from the stockpiles to the ships. Each conveyor system would be fed by a rail mounted bucket wheel reclaimer, with the conveyed material moving directly to the ship loaders with no inter- mediate surge and/or storage bins between the stockpiles and the ships. The bucket wheel reclaimer discharge rates would vary from 0-9600 LTPH in cyclic periods, with the periods varying from 1-5 minutes - dependent on the level of the reclaim buckets in relation to the stockpile as well as the slewing rate of the reclaimer. There would be frequent interruptions for bucket wheel repositioning (laterally and vertically), changing ship holds, and trimming ship holds. These frequent zero flow conditions, approximately 500 per 150,000 ton ship, could last 1-5 minutes. In addition, the conveyors on which the scales were to be mounted would be over the water and subject to the wind and cold of Northern Quebec. These Systems would be in use 350 working days of the year and would load 30,000,000 LT/yr. (An average of 90,000/working day).

Jan 1, 1975

By A Kindred

The Bogong Hydropower Development is a 140 MW high head power project currently under construction in Northern Victoria. The project is the final link in the Kiewa hydroelectricity scheme, which was originally constructed in the 1950s. Due to its location in the Alpine National Park, the waterway for the Bogong project must be located entirely underground. A series of shafts and tunnels is being constructed to transfer the water from the headworks at McKay Creek to the new power station located on the shores of Lake Guy in Bogong village. The difference in elevation between the headworks and the power station is greater than 420 m, which poses particular issues for the design and construction of the waterway. The purpose of this paper is to describe the design and construction planning aspects of the tunnelling and shaft excavation and lining works for the waterway. The tunnelling works includes 5.7 km of hard rock tunnel boring machine (TBM) driven tunnel, 1.1 km of drill and blast tunnel and two deep shafts. The tunnels and shafts are lined with a mixture of permanent rock bolts and shotcrete, concrete lining and steel lining. The viability of the Bogong Hydropower Development relies heavily on the ability of the TBM to excavate at high speed through the East Kiewa Grandiorites. Particular attention was given during the construction planning stage to understanding the excavation characteristics of this material, and designing a suitable hard rock TBM that would be capable of meeting the program requirements of the project.

Jan 1, 2008

By Andrew Mayer

Early in 1942 National Lead Co. was requested by the War Production Board to construct and operate a plant for the Government to produce magnesium by the ferrosilicon process which had been developed by Dr. E. M. Pidgeon in the laboratories of the Canadian National Research Council. A contract with the Defense PlantCorporation was concluded in May 1942 and Magnesium Reduction Co., a wholly owned subsidiary of National Lead Co., was formed to carry out this project. The capacity of the plant was rated at I0,000,000 lb. of magnesium per year, equivalent to an average production of about 14 tons per day. The Process The process, in brief, is as follows: The raw materials are dolomite and ferro-silicon, 75 per cent grade. The dolomite is calcined, the calcine and ferrosilicon are ground and mixed and the mixture is briquetted. The briquets are charged into tubular retorts of chrome-nickel steel set horizontally in a furnace with the open ends projecting outside the front wall. The retorts are then closed and evacuated. Magnesium is liberated according to then reaction 2(MgOl CaO) + Si = 2Mg + zCaO, Si% It is distilled from the charge and con- densed on a removable sleeve in the throat of the retort. Sodium and potassium, if present, are also liberated, distilled and condensed on a "sodium condenser" in the end of the retort. At the expiration of the distillation period the retorts are discharged and the cycle of operations is repeated. For the rated daily capacity of 14 tons of magnesium there are required approximately 170 tons of dolomite, equivalent to about 85 tons of calcine, and 16.5 tons of ferrosilicon. The retort residue, a bulky powder which at present is waste, amounts to about 87 tons. Choosing the Site The investigation to select the location of the plant was conducted by the Research Laboratories of National Lead Co. This work included geologic and economic surveys of a number of districts, examination of dolomite samples by chemical, spectrographic and petrographic methods and large-scale tests of dolomite from several of the more promising localities. in the last-named tests 2-ton samples were put through the ferrosilicon process in the pilot plant of the Canadian National Research Council, under the guidance of Dr. Pidgeon. The conclusions drawn from the investigation, in regard to the quality of dolomite to be used in the ferrosilicon process, were: First, the dolomite should contain not less than 21 per cent MgO and not more than 2 per cent acid-insoluble material. Second, the dolomite should

Jan 1, 1944

By Yoshio Waseda

A laser flash method has been applied to obtain the thermal diffusivity values of Zr55Al10Ni5Cu30 alloy in the liquid, glassy, crystallized and supercooled liquid states. The electrical resistivity of this particular alloy was measured in the glassy, and crystallized states by a direct current four probe technique. A specific heat of Zr55Al10Ni5Cu30 alloy was also determined by a differential scanning calorimeter in the glassy state. On the other hand, thermal diffusivity values for two alloys of Zr60Al15Ni25 and Zr65Al7.5Cu27.5 were measured in the crystallized and liquid states. The thermal diffusivity values of three Zr-based alloys in the liquid state are summarized in the linear equations with positive temperature dependency and it is noted that the lower the thermal diffusivity values of Zr-based alloys at liquidus temperature, the lower the critical cooling rate to obtain metallic glass phase becomes. The thermal diffusivity values of Zr-based alloys were compared with those of Pd-based alloy case. These results suggest that thermal diffusivity of alloy liquids might be an indicator of the glass-forming ability of Zr-based and Pd-based alloys.

Jan 1, 2006

By R. C. Lo, M. D. Scott

"This paper reviews tailings management at Highland Valley Copper, and outlines main features of its tailings storage facility enclosed between the H-H and L-L dams. Key management focusses are: energy efficiency, cost effectiveness, safety and integrity of the tailings impoundment, environmental protection, and reclamation after decommissioning. Main features of the tailings facility include: high international standards for seismic and flood design criteria, water management and water quality monitoring, operations and construction optimization, reclamation and decommissioning plan, and geotechnical challenges associated with the complex geology of the L-L tailings dam foundation.IntroductionHighland Valley Copper stores its tailings mainly in the Highland Valley tailings facility (ultimate capacity: 1.8 billion tonnes). Smaller tailings storage facilities were operated by predecessor companies: the Number One Pond, the Trojan Pond at Bethlehem and the Highmont Pond at the Highmont operation as well as backfilling the Heustis and Jersey lona Pits at Bethlehem. These areas are currently not in use, and are in the reclamation phase prior to decommissioning. This paper focusses on tailings management in the main facility. As indicated in Figure I, the facility includes three tailings dams: these are, going from east to west, the H-H, J-J and L-L Dam, named after the alignment alternatives in the initial feasibility studies. From 1970 to 1977 Canadian Bechtel Ltd. advised Highland Valley Copper's predecessor company Lornex, on tailings storage at the H-H and J-J Dams and on the L-L Dam. Since the completion of the L-L Starter Dam in 1977, Klohn Leonoff Ltd. has provided ongoing consultation and construction monitoring of the raising of the L-L and the H-H Dams. The J-J Dams is currently buried by deposited tailings. This paper reviews key tailings management focusses and main features of the tailings facility."

Jan 1, 1992

By M. E. Sirkka

"INTRODUCTIONInco Ltd. has ten operating mines in the Sudbury district. Over the last ten years mining methods have changed at Inco with special emphasis on the introduction of bulk mining replacing conventional mechanized cut-and-f ill and undercut-and-fill methods. At the same time, the technology and size of LH D equipment has also progressed to meet the demands of bulk mining. This paper will concentrate on various aspects of the introduction and operation of electric LHD equipment a t Inco Limited, Ontario Division. BackgroundInco Limited received its first electric 2 cu. yd capacity LHD in July 1975 at Creighton Mine. The unit was tested pulling shrinkage stope muck and then was moved to a mechanized cut and- fill complex on 6600 Level. The electric scooptram received quick acceptance from the operators, due to its quiet operation and low heat generation, in a relatively hot operating environment. Although there are only two of these units operating a t present, this initial favourable experience, both in cost and efficiency, led to the development and purchase of electric scooptrams of the 5 cu. yd size. There are currently eleven 5 cu . yd electric LHDs in operation.The most recent development a t Inco is the move to yet larger electric LHDs in the 8 cu. yd size. The first electric ""Eight"" has now been in operation at Copper Cliff South Mine for over a year. This unit has the distinction of being the first one of its kind in service in North America. At the time of writing, there were ten 8 cu. yd electric ma chines operating in Inco's Ontario Division Mines, with three on order."

Jan 1, 1989

By Ming-Feng Ye, Jun Wang, Guang-liang Wu

In order to reduce the Al2O3 inclusions in 50Cr5MoV roller steel produced by EBT-LF-VD-VC process in a steelmaking plant, the LF refining slag was optimized and the influence of optimized slags with different w(CaO)/w(Al2O3) ratios on reducing inclusions were investigated in the laboratory. The results showed that, when w(CaO) = 50–55%, w(Al2O3) = 25–30% and w(CaO)/w(Al2O3) = 1.5–2.0, this optimized slag can not only reduce massive Al2O3 come from aluminium deoxidation, but also change the remain into plastic CaO-MgO-Al2O3 spherical compound inclusions with 1–5 lm diameter, the harm on the performance of the steel was minimized.

Mar 1, 2018

By Philip Davidson, Wm. B. Price

The object of this paper is to present, a survey of some of the physical properties of sheet nickel silver when subjected to cold rolling and when annealed at temperatures extending from 350" C. throughout the coininercial annealing range.. A number of alloys were taken from stock and analyzed. Four of these, representing low nickel and high nickel both with and without lead, were chosen for the tests. The analyses were as follows: Alloy Copper, Lead. Iron. Nickel, ManGanese, Zinc, PeR Cent. Per Cent. Per Cent. Per Cent. Per Cent. PEr Cent. A................ 64.68 Trace 0.194 6.73 0.06 remainder B................ 65.82 1.27 0.227 6.17 0.06 remainder C................ 65.44 Trace 0.345 17.83 0.08 remainder D................ 65.60 1.08 0.238 17.77 0.06 remainder These alloys were lolled in accordance with regular mill practice to approximately No. 6 R. & 6. gage. The bars (which were then coiled) were annealed together in a mill muffle and afterwards pickled in a 10 per cent. sulfuric-acid solution and cold rolled in stages of approximately one number (B. & S.) at a time to No. 18 B. & S. gage. After each stage, suitable samples were set aside for physical tests. Additional samples were chosen for tests after the bars were rolled to Nos. 8, 10, 12, and 14 gage. These samples were annealed together in the mill muffle and, after pickling, were finished on 0.050-in. gage, yielding a series of specimens 2, 4, 6, and 8 numbers hard for the subsequent annealing tests. Tensile test pieces 9 by 1 in. (22.9 by 2.5 cm.) were cut from both lots and the central portion was milled to give a test section 2 1/2 in. long by 1/2 in. wide. A distance of 2 in. was marked off on the edge of each specimen with light punch marks. In the case of the annealed alloys, Erichsen test pieces 4 by 235 in. were also taken.

Jan 1, 1921

By H von Blottnitz, J L. Broadhurst

Eco-efficiency has been proposed by the World Business Council on Sustainable Development as an environmental performance indicator framework that contributes to sustainability by assisting corporate decision makers improve the environmental performance of their operations and processes, while also extracting additional economic value. Given that the recent engagement of the minerals industry with sustainability has highlighted the need for requisite tools and methodologies, it is therefore of interest to assess whether eco-efficiency indicators can drive sustainability performance improvement during process design within the minerals industry. Previous work indicates that the choice of sustainability performance indicators to be used for decision making needs to be governed by the decision context; ie the performance indicators need to be fit-for-purpose. Here, the strengths and weaknesses of eco-efficiency indicators are analysed using case studies. First, a more rigorous definition of eco-efficiency indicators for the minerals industry is proposed based on indicators currently offered in the literature. Two case studies are then selected to reflect typical decision situations encountered within minerals process design. For each case study, eco-efficiency indicators are computed and are compared to more traditional graphical representations of the economic and environmental performance of process design alternatives considered. The sensitivity of these indicators to various process design parameters is also investigated. Results confirm that the meaningful application of eco-efficiency indicators is strongly dependent on the decision context in which the process data is generated. Results also show that eco-efficiency indicators can be related to technical process design parameters to allow for richer communication of performance information for various decision trade-offs; however, in some cases, graphical approaches that provide more insights into the environmental-financial trade-offs should be preferred. The research thus contributes to guiding the selection of the appropriate tools for more environmentally sustainable design of minerals beneficiation processes.

Jan 1, 2009

By Henry S. Brown

At least two dozen massive sulfide deposits in the southern Appalachians have supported significant mining operations. Literally hundreds more deposits are known to exist, but are too small to be of commercial interest. Essentially all that are being, or have been, mined are those deposits that were exposed at the surface when first discovered. It is reasonable to assume that many more massive sulfide deposits, large and small, exist hidden not far beneath the surface. The ideas I am sharing with you here today are based both on my personal studies of some of the deposits and on descriptions of deposits in the literature. An attempt will be made to account for the genetic interpretation problems raised by many of these deposits posessing both "syngenetic" and "epigenetic" features. In addition, an examination will be made of the possible relationships between the massive and the not-so-massive sulfide deposits in this region. Hopefully, these observations added to those of others will eventually lead to the synthesis of a better model on which we can base exploration programs in the southern Appalachians.

Jan 1, 1976

By David C. Slack

In recent years public concern over the environment has grown enormously. A very aware populace has exerted pressure on its legislators to enact enforcement laws dealing with pollution. Among the different types of pollution, sulfur dioxide in the air is a large and readily identifiable constituent. Air pollution, according to the EPA, costs the U, S. billions annually with SO2 a major portion of this cost. Fossil fuel and oil fired power plants release better than 50% of the SO2 in the country. Thus great attention is being focused on the methods power plants are utilizing to control emissions. With a time schedule of compliance by early 1975, decisions are being made and systems chosen that will have to perform - and perform - and perform. Therefore, a large majority of the power plants are presently considering lime in the planning and operational phases of their stack gas desulfurization programs. The reasons for this are: Lime scrubbing has more development and pilot work completed than most other methods; the removal potentials are relatively high; the stoichiometric ratios are not excessive and, the process has relatively low capital and operating costs. Many pilot plant studies have been completed recently using lime and the first operational full scale lime scrubbing unit is now in the start-up phase at this time at Duquesne Light Company's Phillips Station here in Pittsburgh. Also, because of completed development work, the problem of solid waste disposal will also be tackled at this power station at the same time. There are various methods for the use of lime in scrubbing for S02, but for our purposes I would like to describe the cyclic wet lime process. This method called "Scrubber Addition of Lime" involves contacting the flue gas with a slurry of milk of lime.

Jan 1, 1973

By Theodore H. Eyde

In the southwest porphyry copper province, the virgin prospect with good copper mineralization cropping out has disappeared. Future discoveries will require an increasingly sophisticated arsenal of exploration techniques and concepts. One of the latter, stratigraphic analysis, is a technique which is often overlooked. A surprising number of exploration geologists still think of porphyry copper deposits as occurring wholly within intrusive bodies such as quartz monzonite or granodiorite. Disseminated copper mineralization, though genetically related to intrusive rocks, can occur within both the intrusive and the intruded rocks. At present, as much as 30% of the total copper produced from disseminated copper deposits in the Southwest originate from the intruded rocks rather than the intrusive. George M. Schwartz, in "Geology of the Porphyry Copper Deposits of Southwestern North America" points out that the host rocks at porphyry copper deposits include such diverse rock types as diabase, granite, limestone, dolomite, quartzite, skern, sericite schista, and others in addition to the more common monzonite, quartz-monzonite, and diorite porphyrys. Therefore, a porphyry copper can be defined as a disseminated copper deposit occurring either in or adjacent to a granitic-monzonitic-dioritic intrusive which can be exploited using bulk. mining techniques. The original definition of porphyry was originally applied to the early producers, such as Inspiration, Bingham, and Ajo, in which the copper mineralization occurred principally within the intrusive. A review of the geologic literature describing the porphyry geologic

Jan 1, 1971

By D. W. Smellie

This paper is a review of technological progress in mining geophysics during the past decade. This has been the most significant period in the history of mining geophysics. Among the already existing; techniques, instruments for ground -magnetic and electromagnetic prospecting, were developed that are more, portable and faster to operate. Induced polarization equipment came into widespread use. Airborne instruments of various types became available and were used to survey large areas. Drillhole instruments were developed and have had some use, and it is to be hoped will be used to a greater extent in the future. Two revolutionary new methods, the AFMAG and INPUT, were developed. The wisdom of attempting to cover such a broad field in a single paper might be questioned. There is the inevitable problem that each topic must be discussed very briefly. However, while papers describing individual instruments have appeared, many have yet to be described in the technical literature. The evolution of the ground magnetometer and electromagnetic instruments has not been discussed. It is only recently that a review article has appeared on airborne EM. The existence of review literature on some topics has meant that they are given less emphasis in this review than those topics inadequately covered. It will also be observed that stress is laid on "chose instruments that are generally available to the mining industry rather than those developed by individual exploration companies for their own use.

Jan 1, 1963

By K. T. Cunningham

The Oakfield, New York Hine of the United States Gypsum Company is a shallow, room and pillar mine developed in the Camillus Formation of Silurian Age on the up-dip edge of the northern Appalachian Basin. The gypsum comes to subcrop beneath a variety of glacial materials and is subject to solution activity by groundwater. A geologic environment unfavorable to mining activity is thus created. Since 1978 seismic studies have been used to supplement core drilling to determine a conservative boundary between normal and questionable mining environments. A single channel seismograph, originally in use, is now replaced by a twelve-channel unit and is used to determine bulk material velocity which is the basis for defining the mining limit.

Jan 1, 1987

By E. A. Gulbransen, K. F. Andrew

The vacuum-microbalance method was used to study the oxidation behavior of Zircaloy-2 and -3A over the temperature range of 300 to 850°C and at 0.1 atm pressure. The results fit in well with the authors' earlier studies on zirconium. Tin was found to increase the rate of oxidation and also the temperature at which the metal burns. Both the cubic-rate law and the parabolic-rate law gave imperfect fits to the rate data. Since the parabolic-rate law has been derived from accepted physical principles, this rate law was used to interpret the rate data. A heat of activation of 28,600 cal per mole was calculated. The transition phenomenon previously observed in hot-water and steam-corrosion processes was studied systematically for oxygen atmospheres. Observations on the rate of oxidation, color and properties of the oxide films show that the transition phenomenon was associated with a failure in the adherence of the oxide to the alloy. ZIRCALOY-2 and -3A have found important uses in the field of reactor metals due to their low neutron adsorption, good strength and good resistance to corrosion. One feature of the corrosion reaction in steam or hot water is the sharp transition in the rate of corrosion to a higher value after a certain amount of reaction has occurred. This paper presents a study of the reaction of Zircaloy-2 and -3A with oxygen including a study of the transition phenomenon which has been found to occur also in oxygen atmospheres. A comparison will be made between the oxidation behavior of these alloys and the pure metal. It was hoped that a study of the details of the oxygen reaction would lead to a better understanding of the reactions occurring in hot-water and steam atmospheres. Literature Kinetics-—The reaction of Zircaloy-2 and -3A with hot-water and steam atmospheres has been studied by Thomas.' Goldman and Thomas,' Thomas and Forscher," and Thomas and Kass.' Empirical equations for the kinetics of the reaction have been given by Thomas and Forscher." The change from the initial slow rate of reaction to the final rapid rate of reaction has been termed transition with the post-transition corrosion kinetics following a simple linear equation in time. The corrosion behavior in high-temperature steam was similar in many features to the corrosion in high-temperature water. Goldman and Thomas' and Pray and Peoples' have shown that the addition of tin, while increasing the rate of corrosion, counteracts the deleterious effect of nitrogen. The beneficial effect of iron, nickel and chromium was to improve the adhesion of the oxide to the metal as well as to counteract the deleterious effect of nitrogen. Mallet and Albrecht" have studied the oxidation of two zirconium-tin alloys. The cubic-rate law was found to fit the oxidation data for the 1.5 pct tin alloy while the parabolic-rate law was found to fit the data for the 2.5 pct alloy. Kendall' in a recent paper has studied the oxidation of Zircaloy-2 containing 1.5 pct tin in air atmospheres. Transition Phenomenon—In steam atmospheres Thomas' has observed fora 1.8 pct tin alloy containing small amounts of iron, nickel and chromium that transition to a more rapid rate of corrosion at 400°C

Jan 1, 1959

By G. C. Presley

With plant construction scheduled for the Spring of 1997, U. S. Zeolites will become the new source for quality in natural zeolites. The company will selectively mine, dry process, package, and market a very high quality clinoptilolite possessing many unusual properties. These unusual chemical and physical properties provide a multitude of industrial, commercial, and consumer applications. Extensive testing has determined many potential applications.

Jan 1, 1997

By Charles E. Lundin

The character of the Er-D system was established by determining pressure-temperature-composition relationships. A Sieuerts&apos; apparatus was employed to make measurements in the temperature range, 473" to 1223"K, the composition range of erbium to ErD3, and the pressure range of 10~s to 760 Torr. The system is characterized by three homogeneous phase regions: the nzetal-rich, the dideuteride, and the trideuteride phases. These phases and their solubility boundaries were deduced from the family of isotherms of the system zchich relate the pressure-temperature-composition variables. The equilibrium plateau decomposition relationships in the two-phase regions were determined from can&apos;t Hoff plots to be: The differential heats of reaction in these two regions are AH = - 53.0 * 0.2 and -20.0 *0.1 kcal per mole of D2, respecticely. The differential entropies of reaction are AS = - 36.3 * 0.2 and - 31.0 * 0.2 cal per mole D2. deg, respectively. Relative partial molal and intepal thermodynamic quantities were calculated from the pure metal to the dideuteride phase. The study of the Er-D system was undertaken as a logical complement to an earlier study of the Er-H system.&apos; The primary interest was to compare the characteristics of the two systems and relate the difference to the isotopic effect. Studies of rare earth-deuterium systems by other investigators have been very limited in number and scope. Furthermore, there is even less information available wherein an investigator has systematically compared a binary rare earth-hydrogen system with the corresponding rare earth-deuterium system. The available information consists primarily of dissociation pressure measurements in the plateau pressure region of a few rare earths. Warf and Korst&apos; determined dissociation pressure relationships for the La- and Ce-D systems in the plateau region and several isotherms for each system in the dideuteride region. They compared these data with those of the corresponding hydrided systems. The study of these systems as a whole was very cursory and did not give sufficient data for a thorough comparison of the effect of the hydrogen vs the deuterium in the respective rare earths. The heat capacities and related thermodynamic functions of the intermediate phases, YH, and YD2, were determined by Flotow, Osborne, and Otto,~ and the investigation was again repeated for YH3 and YD3 by Flotow, Osborne, Otto, and Abraham.4 This investigation studied only these specific phases. Jones, Southall, and Goodhead5 surveyed the hydrides and deu-terides of a series of rare earths for thermal stability including erbium. They experimentally determined isotherms of selected hydrides and plateau dissociation pressures for deuterides. These data allowed comparison of the enthalpy and entropies of formation of the dihydrides and dideuterides. To date, no one rare earth has been selected to thoroughly establish the complete pressure-temperature-composition (PTC) relationships of binary solute additions of hydrogen and deuterium, respectively. The objective in this investigation was to provide the first comparison of a complete family of isotherms of a rare earth-deuterium system with those of a rare earth-hydrogen system. This would allow one to determine what differences exist, if any, in the various phase boundaries and the thermodynamic relationships in various regions of the systems. I) EXPERIMENTAL PROCEDURE A Sieverts&apos; apparatus was employed to conduct the experimental measurements. Briefly, it consisted of a source of pure deuterium, a precision gas-measuring buret, a heated reaction chamber, a mercury manometer, and two McLeod gages (a CVC, GMl00A and a CVC, GM110). Pure deuterium was obtained by passing deuterium through a heated Pd-Ag thimble. A 100-ml precision gas buret graduated to 0.1-ml divisions was used to measure and admit deuterium to the reaction chamber. The reaction unit consisted of a quartz tube surrounded by a nichrome-wound furnace. The furnace temperature was controlled by a recorder-controller to . An independent measurement of the sample temperature in the quartz tube was made by means of a chromel-alumel thermocouple situated outside, but adjacent to, the quartz tube near the specimen. Pressure in the manometer range was measured to k0.5 Torr and in the McLeod range (10~4 to 10 Torr) to *3 pct. The deuterium compositions in erbium were calculated in terms of deuterium-to-erbium atomic ratio. These compositions were estimated to be *0.01 D/Er ratio. The erbium metal was obtained from the Lunex Co. in the form of sponge. The metal was nuclear grade with a purity of 99.9+ pct. The oxygen content was reported to be 340 ppm and the nitrogen not detectable. Metallographically the structure was almost free of second phase (<i vol pct). A quantity of sponge was arc-melted for use as charge material. The solid material was compared with the sponge in the PTC relationships. They were found to be identical. Therefore, sponge material was used henceforth, so that equilibrium could be attained more rapidly. The specimen size was about 0.2 gr for each loading of the reaction chamber. The procedure employed to obtain the PTC data was to develop experimentally a family of isothermal curves of composition vs pressure. First, a specimen

Jan 1, 1969

By Parke A. Hodges

CHROMIUM, one of the most vital of the strategic metals, has constantly increasing importance as research expands potential uses in alloy steel metallurgy. All signs point to a steadily growing use for chrome ore, and the general subject has received a great deal of attention recently.1 A relatively little known country, Southern Rhodesia produced a total of 5.949 million tons, or 18.6 pct of the total world chrome output, between 1906 and 1950, according to figures from the U. S. Dept. of Commerce. According to U. S. Bureau of Mines figures, Southern Rhodesia produced 291,525 tons in 1950 and 300,267 tons in 1951, or approximately 13 and 11 pct, respectively, of world production for the two years. In 1953 the Rhodesian Vanadium Corp. produced about 85,000 tons of which probably 7,000 tons were concentrate. Production by other companies was high. Large in themselves, the figures assume even greater significance because most of this output is of metallurgical grade.

Jan 8, 1954

A revolutionary development in blasting materials has occurred in the past 5 years. Ammonium nitrate, sensitized by the addition of a few percent of No. (class) 2 diesel fuel or other suitable petroleum product, has been adopted as a low-cost, efficient blasting agent2/ by a wide variety of mining and heavy construction operations. Moreover, ready availability of the component supplies throughout the Nation and ease of their formulation into effective blasting agents have made it possible for the blaster himself to pre-pare the mixes at the site of use. Although these field-mixed products have partly or wholly displaced explosives such as dynamites in some applications, there are other blasting operations where the fuel-sensitized ammonium nitrate agents do not appear to be well adapted. Important safety characteristics are inherent in ammonium nitrate-based blasting agents prepared under competent factory control, or when field mixed under equivalent close control--as long as the hazards they present are clearly understood and respected. This publication attempts to summarize knowledge of those hazards and to incorporate practical ways to cope with them. A series of safety recommendations thus is presented. These recommendations cover the preparation, storage, transportation, and use of field-mixed ammonium nitrate blasting agents.

Jan 1, 1960

By J. J. Jakosky

"This report is the second of a series dealing with electrical methods of underground communication nd signalling, and is a discussion of some of the factors involved in -applying radio in mines.A previous report2 described the results obtained by the use of the ""T.P.S."" of ground-conduction method of signalling, and outlined in a general way the requirements for a practical mine communication apparatus.The popularity of radio, the development work on new apparatus, a desire to render humanitarian service to entombed miners, and an endeavor to find new uses and applications for radio stimulated many persons to attempt the application of radio to mine rescue purposes. A number of experiments on underground reception from surface broadcast stations have been conducted by different experimenters in various parts of the country and the widespread interest in the subject is shown by the fact that these tests have been con¬ducted in many States, The Bureau of Mines has received information regarding, underground tests in Illinois, Pennsylvania, Arizona, Utah, Idaho, Colorado, Michigan, Wyoming, Kentucky, New York, Connecticut, and in England, Germany, Italy, and Franc.From occasional press notices and illustrations in different papers it may appear that radio communication in mines and in tunnels being excavated is en established fact, and that the method is comparatively simple. As a matter of fact the reverse is the case."

Apr 1, 1924