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By Joan T. May

The Bureau of Mines conducted laboratory tests to evaluate the production of high-purity H3P04 by HCl digestion and solvent extraction. Both batch and bench-scale continuous tests were made. Western phosphate rock concentrates were acidulated with HCI, and the digestion liquors were processed by solvent extraction. Phosphoric acid was extracted with isoamyl alcohol and recovered from the organic extract by contact with an NH4F solution. This solution was fractionally distilled to yield high-purity H3P04. The raffinate from solvent extraction was treated with lime to precipitate CaF2, which was subjected to steam pyrolysis to generate HF. This method was successful in recovering 95 pet of the phosphate and 80 pct of the fluoride contained in the concentrates.

Jan 1, 1976

By K. Awuah-Offei

Energy efficiency has become significant due to cost and environmental considerations. Comminution and material handling have been identified as the two most energy intensive processes in mining. The objective of this work was to evaluate truck-shovel energy efficiency strategies using discrete event modeling. Energy audits and time and motion studies were conducted at a surface coal mine to acquire data. A discrete event simulation model of truck-shovel operations was built in Arena® and validated with the field data. The model was used to evaluate the effect of using a larger shovel, and optimizing truck-shovel matching on fuel efficiency. The results indicate that using a larger excavator increases the fuel efficiency of the operation while optimizing truck-shovel matching does not. However, using a larger shovel will lead to under-utilization of the shovel. This work shows the potential benefits of using discrete event simulation to model energy efficiency of mining operations.

Jan 1, 2012

By Robert Vinson

This article examines the spatial variability of dust concentrations within a coal miner?s breathing zone and the impact of sampling location at the cap lamp, nose, and lapel. Tests were conducted in the National Institute for Safety and Health Pittsburgh Research Laboratory full-scale, continuous miner gallery using three prototype personal dust monitors (PDM). The dust masses detected by the PDMs were used to calculate the percentage difference of dust mass between the cap lamp and the nose and between the lapel and the nose. The calculated percentage differences of the masses ranged from plus 12% to minus 25%. Breathing zone tests were also conducted in four underground coal mines using the torso of a mannequin to simulate a miner. Coal mine dust was sampled with multi-cyclone sampling cans mounted directly in front of the mannequin near the cap lamp, nose, and lapel. These four coal mine tests found that the spatial variability of dust levels and imprecision of the current personal sampler is a greater influence than the sampler location within the breathing zone. However, a one-sample t-test of this data did find that the overall mean value of the cap lamp/nose ratio was not significantly different than 1 (p-value = 0.21). However, when applied to the overall mean value of the lapel/nose ratio there was a significant difference from 1 (p-value < .0001). This finding is important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

Jan 1, 2007

By Stephen Northey, Nawshad Haque, Terry Norgate

"Life cycle assessment (LCA) is a recognized tool to evaluate various processing routes for metal production. Declining ore grades and higher specific energy requirements for primary metal production put greater emphasis on recycling. Greenhouse gas (GHG) emissions of steel and aluminium metal production were quantified with recycling scenarios using material recovery facility (MRF) data from the database of SimaPro LCA software. The GHG footprint of the MRF is relatively minor compared with that of associated transport during collection (i.e. 10 times more than MRF) of curbside recyclable material. Additionally, if the bulk recyclable material is sent overseas (i.e. Australia to China) from the MRF for further processing, the GHG footprint of shipping can significantly be larger compared with the sum of the collection and MRF (assuming electricity is from same source). Thus opportunities exist for reducing GHG emissions from secondary metal production if it is processed close to the MRF.IntroductionIt is a challenge to recycle metals significantly, although theoretically infinite recycling is possible due to their elemental nature. Leaks from the metal stocks in society occur through corrosion, wear and dispersive uses, or via land filling or similar activities that return metals to the earth. In order to provide a technically sound and transparent assessment of metal recycling, a methodology such as life cycle assessment (LCA) should be used. By taking a life cycle perspective, the beneficial recycling properties of metals can be evaluated in a manner that enables appropriate comparisons with other materials or product systems that do not have recycling loops. In practice, mixtures of primary and secondary metals are often used in new products, and also at the end-of-life various processing methods are used for recycling.The difficulty of introducing recycling into LCA is to set the right boundaries for the different flows ending in different product systems. It is a question of which observed material flow belongs to the first product system and which one to the second or subsequent systems. Recycling can be part of any product LCA. However, it is often a complex issue which requires specific considerations. As pointed out by Yellishetty et al. and Birat et al. [l, 2], LCA practitioners are left with much freedom in allocation of environmental burdens to account for recycling, thus making subjective judgments on recycling and allocation of credits to recycling. This often makes it difficult to compare the results of LCA studies conducted by two different practitioners even on the same processes. As LCA is often used to define policy in government, business and society circles, it should be based on a sound, objective and unbiased description of recycling."

Jan 1, 2014

By B. R. Mohal, F. F. Aplan, S. Chander

"ABSTRACTThe wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5 ] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3( CH2 )8-C6H4,- ( OC2H, ) n, where n is the number of ethoxy groups) . The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3)2-C6H4- ( OC2H4) n ).Initial wetting rates — modified Walker techniqueWalker et al. [ 6 ] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7 to determine the effect of surfactants on wettability of cotton fibers. In this procedure commonly known as the Draves test, the concentration of a surfactant required to give a 'sink time' of 25 s is determined.Other investigators have used slight variations of the Walker method to study the wetting of fine particles [ 8-12 ] , by measuring the time for wetting a given amount of powder. There are differences in the manner in which the time of wetting is measured, however. Some investigators measure the time for the last trace of coal to disappear [ 8,11 ] whereas others determine the time for the vast majority of particles to sink [ 10 ] . Some investigators report a wetting rate [ 11 ] which is a value calculated on the basis of the time for the 'last traces of particles to sink'. The differences in choice of criterion for wetting can result in different values for wetting rates as illustrated in Fig. 1 which is based upon our measurements of the amount of powder wetted as a function of time. The procedure for wetting rate measurements is described in the next section. The technique in which time for disappearance of the 'last traces of particles' is determined gives the smallest value for the wetting rate, while the technique in which the time for wetting of the 'vast majority' of particles is determined will give intermediate rates. The terms 'last traces of particles' and 'vast majority of particles' are usually not defined explicitly and can lead to large differences in wetting rates measured by different investigators. Since our measurements show that the wetting rates for an assembly of powder decreases with time, we have used the initial wetting rates to compare the wetting behavior of coal in solutions of different surfactants."

Mar 1, 1989

By S. G. Gendler

One of the ways of trauma and occupational diseases level reduction is noted to be the improvement of the labour protection measures planning. As an indicator for prospective trends determination in the labour protection planning improvement sphere economic risk has been proposed to be used. The trauma and occupational diseases analysis based on the correlative and regressive methods has been carried out for the “Vorgashorskaya” mine of Pechora coal basin. Trauma and occupational diseases occurrences frequency and economic losses value have been estimated. Trauma and occupational diseases economic risk distribution analysis has been presented in respect to the different subdivisions and occupational groups of “Vorgashorskaya” mine.

Jan 1, 2003

By R. K. Zipf

Recent scientific studies by researchers at the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Army Corps of Engineers (USACE) presented the worst-case explosion pressures that can develop if a methane-air mixture of a certain composition and dimension accumulates and ignites within a sealed area of a mine. The Mine Safety and Health Administration (MSHA) issued its final rule on sealing of abandoned areas which considers potential explosion pressures and the risk of achieving the necessary conditions. The new MSHA seals regulation has increased the pressure design criteria an order of magnitude beyond the old standard of 140 kPa (20 psi) to 800 kPa (120 psi). However, there still are major knowledge gaps pertaining to seals and sealed areas including: (1) the composition of the sealed area atmosphere and how it changes in time and space, (2) explosion pressures that might actually develop within sealed areas, (3) engineering procedures to follow when designing seals and seal installations, and (4) guidelines to manage the atmosphere within sealed areas with monitoring or inertization. NIOSH has initiated a seals research program with collaborators from Safety in Mines Testing and Research Station (SIMTARS) in Australia, West Virginia University (WVU), the Naval Research Laboratory (NRL), and USACE. Highlights of progress so far include: (1) construction of a gas explosion tube at Lake Lynn Laboratory for studying large methane-air explosions, (2) computer simulation of the fluid dynamics of high pressure methane-air explosions, (3) development of seal analysis methods considering construction materials, reinforcement and the seal foundation, and (4) development and testing of innovative seal designs that utilize inexpensive, readily-available rock rubble to resist high explosion pressures. NIOSH researchers aim to provide sound engineering guidelines to better address the new MSHA seal regulations. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Nagy El-Kaddah, T. T. Natarajan

This paper describes a novel approach for modeling three-dimensional electromagnetically driven flow in inductively stirred systems, and its application to modeling electromagnetic and flow phenomena in sub-mold rotary stirring of billets. It is based on a new T-\jf potential formulation of electromagnetic field, which does not require the calculation of the field in free space. A finite element algorithm has been developed for solving the electromagnetic field and Navier-Stokes equations in the fluid flow domain. The computed results have shown that the electromagnetic force field generates a strong rotational flow within the vertical section covered by the stirrer, and a relatively strong secondary flow beyond the stirrer. It has also been shown that the rotational and secondary flows were driven primarily by the vorticity of the force field at the billet corners. The induced flow in the molten pool was found to be turbulent and the effective mixing region in the molten pool was about three times the length of the stirrer. The mathematical approach presented in this paper provides the theoretical framework for quantifying these effects for any given stirrer configuration and operating parameters.

Jan 1, 1999

By Stephen D. Cramer

The Bureau of Mines conducted a series of in situ linear polarization measurements in high-temperature, high-pressure hypersaline geothermal brines at the Bureau of Mines Geothermal Test Facility in the Imperial Valley of California. The measurements represented an evaluation of the linear polarization technique for obtaining instantaneous corrosion rates of materials of construction in flowing hypersaline hydrothermal fluids that rapidly form scales on exposed surfaces. A special method was devised for use with the linear polarization technique that resulted in obtaining corrosion rates for 1020 carbon steel, 316 and 430 stainless steel, titanium, various nickel-based alloys, and aluminum 6061 under strong scale-forming conditions. The measurements also provided information on scale-deposition rates in various geothermal environments. Exploratory in situ potentiostatic polarization measurements were made in the flowing brines to qualitatively determine scale-deposition effects on the electrochemical measurements.

Jan 1, 1978

By G. R. Leverant, C. P. Sullivan

To evaluate the effect of a dispersion of nondeform-able, incoherent, second-phase particles on high-strain cyclic deformation and fracture, recrystallized TD-nickel (Ni-2ThO2) and a commercially pure nickel, Ni-200, were fatigued under strain control at total strain ranges varying from 0.009 to 0.036. Relative to the Ni-200, the slip at the surface of the TD-nickel was more wavy and discontinuous due to the presence of the thoria particles. This made crevice formation (incipient cracking) within slip bands more difficult in TD-nickel than in Ni-200. Both materials cyclically hardened to a constant (saturation) flow stress which increased with increasing plastic strain amplitude. Cellular substructures were developed in both materials during cycling. The cell size in TD-nickel was controlled by the thoria particle distribution and was independent of plastic strain amplitude over the range investigated. The cell size in Ni-ZOO was larger than that in TD-nickel at similar plastic strain amplitudes and was a function of plastic strain amplitude. These results, together with the cyclic stress-strain curves for both materials, are discussed in terms of a model for fatigue strain accommodation at saturation recently proposed by Feltner and Laird. NUMEROUS fatigue investigations have considered the interrelation of slip character, dislocation substructure, and cracking in pure metals and solid-solution alloys. However, except for the studies of the low-strain fatigue of internally oxidized copper alloys1 and cast, dispersion-strengthened lead,&apos; little is known about the effects which small, incoherent, nondeform-able, second-phase particles have on cyclic deformation and cracking processes. Effects due to the particles alone are often obscured by a dislocation substructure introduced during thermomechanical processing of dispersion-strengthened metals. In the present study, recrystallized TD-nickel and a commercially pure nickel, Ni-200, were employed to evaluate the effect of a thoria dispersion on high-strai fatigue deformation and cracking at room temperature. I) MATERIAL AND EXPERIMENTAL PROCEDURE The TD-nickel was supplied by DuPont as a 5/8-in.-thick stress-relieved plate which had been subjected to a proprietary schedule of thermomechanical treatments, and the Ni-200 as 3/4-in. bar which was subsequently annealed for 2 hr at 850°C in argon resulting in an average grain diameter of 0.05 mm. The compositions of these materials are given in Table I. The microstructure of the TD-nickel consisted of elongated grains parallel to the primary working direction with an average width of 0.16 mm, Fig. l(a). Many fine annealing twins were present indicating that the starting material was in a recrystallized condition; this supposition was confirmed by the absence of of any extensive dislocation substructure, Fig. l(b). Sheetlike stringers parallel to the rolling direction were occasionally seen both within grains and at grain boundaries. Some approximately spherical particles about 2 in diam, which may correspond to exceptionally large thoria particle aggregates, were also present. The average Young&apos;s modulus of the plate material in the rolling direction was 21.8 X 106 psi which is consistent with a {100}<001>recrystalliza-tion texture3&apos;* being prominent. In transmission microscopy, the 2.3 vol pct of thoria particles generally appeared to be uniformly distributed although some clusters, 0.1 to 0.3 in diam, of larger particles were observed as previously reported for TD-nickel sheet,5 and stringering of particles was present in some areas as welt. The average diameter of the thoria particles was 450A with a calculated mean planar center-to-center spacing of 2100A, as determined by quantitative metallographic analysis.= The 0.2 pct offset yield stress was 36,000 psi which agrees with the value predicted by the modified Orowan relation7 for edge dislocations bowing between thoria particles of the size and spacing observed in the present investigation. Fig. 2 illustrates the specimen design employed for the axial high-strain fatigue testing. Adapters were screwed onto the threaded portions of each specimen so that testing could be performed in the same manner as that reported for buttonhead specimens.8 Stressing was coincident with the working direction for both materials. The gage section of each specimen was electropolished and lightly etched prior to testing. The total strain was controlled, being varied between zero and a maximum tensile strain ranging from 0.009 to 0.036. In addition to these tests, a circum-ferentially notched TD-nickel specimen was cycled over a total strain range of 0.0075. The same strain

Jan 1, 1969

By B Murphy, A Uliana, P STrgio de Oliveira, G Ara·jo de Souza Franco, T Miettinen

Outotec has performed numerous research and development projects and various surveys in the study of reverse iron ore flotation. Over the past four years their TankCell-70 and TankCell-160 flotation cells at the Germano concentrator of Samarco in Brazil were extensively surveyed. These surveys have revealed some extreme operating conditions in reverse iron ore flotation and are the subject of this paper. Some of the findings include large variations in the content of solids in the various flotation stages. At the bottom of the cleaner cells, the content of solids by weight reached over 60 per cent, whereas at the bottom of the scavenger cell this was less than 50 per cent. Froth carry rates were also significantly different in the various flotation stages. In the case of coarse material, the scavenger cells operated at a froth carry rate of over 40 t/h.m2. With fine material, however, froth carry rates of less than 10 t/h.m2 were measured. High froth carry rates caused significant changes in the residence times at Samarco. In the rougher cells, the fifth cell had more than double the residence time of the first cell. This was even more pronounced with the scavenger cells, where the second cell had more than triple the residence time of the first cell. High froth carry rates also caused losses in iron recovery. As a consequence of such findings, it appears that different rules apply in the sizing of reverse flotation circuits compared to direct flotation circuits. Different operating parameters (mixing intensities and air flow rates) must also be used in the rougher, cleaner and scavenger cells in order to optimise the metallurgical performance. Outotec has also been working on a number of new technologies aimed at improving the metallurgical performance of iron ore reverse flotation circuits by increasing froth carry rate and decreasing fine iron entrainment.CITATION:Miettinen, T, Uliana, A, Ara·jo de Souza Franco, G, STrgio de Oliveira, P and Murphy, B, 2013. TankCell flotation at SamarcoÆs Germano concentrators, in Proceedings Iron Ore 2013 , pp 441-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By D. D. Runnells

This study focused on the chemical reactions between uranium tailings fluids and cores of subjacent bedrock from the site of the Cotter Corporation uranium mill at Canon City, Colorado. Actual and synthetic tailings fluids were forced through cores of bedrock. The pH of the effluent solutions was the dominant control on the behavior of dissolved species in solution. The pH depended on the presence or absence of calcite cement in the rocks. Calcite neutralized acidic raffinates and caused the precipitation of iron, manganese, aluminum, and possibly uranium. Chloride, sulfate, and sodium were not retarded upon passage through the cores, and sulfate and chloride should be useful as tracers of escaping tailings fluids. Zinc, copper, cobalt, nickel, uranium, and vanadium exhibited high mobility under acidic conditions and were strongly retarded at elevated pH. Calcium was released due to dissolution of calcite and ion-exchange. Magnesium was not retarded in concentrated solutions, but showed moderate retardation in dilute fluids. Potassium and ammonium both showed early retardation followed by breakthrough and mobility. The behavior of molybdenum was strongly dependent on pH, with retardation at low pH and mobility at elevated pH. Selenium was highly mobile under all conditions. Selenium should be a better tracer than molybdenum for many situations. Precipitation of carnotite appears to control the solubility of uranium and, possibly, vanadium. With the exception of the precipitation of aluminum and silica, all reactions were rapid.

Jan 1, 1983

The Pinto Valley, Arizona, plant of Cities Service Company is one of the newest copper producers in the United States, having started production in 1975. It is located a few miles west of Miami, Arizona, on the site of the Castle Dome Mine, a World War II operation which was shut down and its mill later moved and renamed the Copper Cities plant. The Pinto Valley concentrator uses six 18 ft (5. 5 m) diameter by 21 ft (6.4 m) long, 4000 hp, single-stage ball mills, taking crushed ore from four 7 ft (2. 13 m) standard and eight 7 ft shorthead crushers. It has a design capacity of 40,000 stpd but has higher tonnage capability for an expanded concentrator. The copper porphyry-ore is mined by two 15 yd and one 20 yd shovels (11.5 and 15.3 cu m) and is transported to the primary crusher by 150-ton trucks. The dump pocket is relatively shallow (14 ft or 4. 27 m deep); and because of the width necessary for the 150-ton trucks, it was designed to use the ore itself instead of manganese steel as an abrasion- resistant lining, although a heavy steel cap protects the dump pocket top edge. The pocket has a capacity of 300 tons of ore. Water sprays under the dumping positions direct a fog toward the truck being dumped for excellent dust control. Breaking of oversize is done by a hydraulic impact breaker mounted on a hydraulically operated articulated arm situated at the side of the dump pocket. Again because of the shallow pocket, no splitter is used to protect the spider of the 60 in. by 89 in. Traylor gyratory crusher, which is equipped with a hydroset mechanism. Crushed ore at 8 in. (203 mm) drops into the 360 st surge chamber lined with AR plate and then is fed directly to the 60 in. (1.52 m) stock- pile conveyor by an 84 in. by 20 ft (2. 13 m by 6.1 m) four-speed apron feeder at a rate of up to 4000 stph. Early in 1977, Cities Service will replace the four -speed electric drive with a hydraulic pump and motor with infinitely variable speed. They are also studying the replacement of the apron feeder with an 8 ft wide (2.44 m) belt feeder similar to those at Similkameen and Palabora. Peak crushing capacity would then be increased to 5000 stph. The AR plate in the crushed ore pocket was installed in large, rectangular sheets which required much less embedded metal to hold it in place than would the more conventional, smaller arid square pieces of cast manganese steel. For duty in the crushed ore pocket, where wear is not severe, the AR plate is a satisfactory material. The new Palabora Figure-8 crusher also uses this design.

Jan 1, 1978

By Tom Snyder, John Brulia

PART 3 – UN Identifi cation Markings for the Highway Transportation in Commerce of Bulk Explosives, Oxidizers, and Combustible Liquids

Jan 1, 2015

By Gabsoo Kim, Rulin Yang, Dave Kay

Blast vibration data, such as PPV are usually scattered. In many cases, plots of PPV versus the charge weight scaled distance are so scattered that useful trends from different blast designs cannot be identified. The scattering of the data may be attributed to the inaccuracy of the PPV measurement, the definition of the scaled distance from a multiple-hole production blast, and the measurement of distances and charge weights. The error from vibration measurements is one of the major contributors to the scattering of the plots. If accurate monitoring is conducted, improved design options may be identified. This paper documents two case examples that compare different vibration sensor couplings. The first case shows mounting accelerometers at spots that protrude from the ground, compared with the sensors that were mounted on a flat ground surface. The second case compares data from loose-sand buried geophone with that from sensors coupled to the ground using concrete blocks.

Jan 1, 2014

By G. Vouille, P. Bérest

Residual stresses observed in rocks often result from non-compatible initial strains. These stresses can be determined when the incompatibility tensor associated with the initial strain tensor is known. The residual stresses in a cylindrical rock sample can be computed the sample is considered small enough for its incompatibility tensor to be constant. Les contraintes résiduelles, dont on observe couramment les manifestations dans les roches, résultent souvent de l’existence de déformations initiales non-compatibles. Ces contraintes peuvent être calculées lorsque le tenseur d’incompatibilité associé aux déformations initiales est connu. Les contraintes résiduelles dans une éprouvette cylindrique sont données dans le cas où le tenseur d’incompatibilité est constant. Eigenspannungen, die man haeufig in Steinen beobachtet, sind oft Ergebnis einer inkompatiblen Deformation des Anfangszustandes. Diese Spannungen koennen berechnet werden, wenn der Inkompatibilitaets-Tensor der Anfangsdeformation bekannt ist. Die Eigenspannungen einer zylindrischen Probe werden fuer Fall eines konstanten Inkompatibilitaets-Tensor bestimmt.

Jan 1, 2003

By Robert Hopler

In the annual report under the Explosives Act for 1905, H.M.inspectors state that over 90 percent of the accidents causing death or personal injury occurred in the use of explosives and under miscellaneous conditions to which the controlling provisions of the Act do not apply, and that such accidents caused 43 out of the 50 deaths, and 312 out of 348 cases of injury. The number of accidents grouped under the heading of “Use and Miscellaneous” is less than that for 1904 - viz., 281 against 301. By these accidents 43 persons were killed and 312 injured, as compared with 39 killed and 343 injured in 1904

Jan 1, 2007

By R. V. Hopper, M. E. Wilson, L. S. Trenholme

"The Company known as Rouyn Merger Mines, Limited, was formed in 1943 to take over the ownership of claims in Rouyn and Joannes townships formerly held by East Rouyn Mines, Limited, O'Neil Thompson Mines, Limited, and the Hosking-Cockeram Prospecting Syndicate. The NorandaSenneterre branch of the Canadian National railway passes in an approximately east-west direction through almost the entire length of the property. Since 1937, sixty-three diamond drill holes have been drilled from the surface to cross faults on the contact of the Timiskaming sediments with the Abitibi ( Keewatin) volcanics, along which ore has been found to occur. Late in 1945, the sinking of a 3-compartment inclined shaft in the andesite agglomerate beneath the ore zone was commenced. On January 17th, 1947, this shaft had a depth of 944 feet; cross-cuts have been driven north-northwest from the shaft at 150-foot intervals from depths of 200 to 800 feet on the shaft (Fig. 2).GEOLOGYThe western or East Rouyn part of the Rouyn Merger property in which ore is being mined adjoins the area owned by McWatters Gold Mines, Limited, on the east and is underlain by the eastern continuation of the McWatters formations. As at the McWatters, the rocks belong structurally to three areas: (1) the territory north of the Cadillac-Bouzan Lake fault, occupied almost wholly by Abitibi ( Keewatin) volcanics; (2) the area along the south boundary of the property, underlain by Timiskaming conglomerate and greywacke; and (3) the synclinal belt of McWatters volcanics and sediments between areas 1 and 2.1Bouzan fault of Hawley."

Jan 1, 1954

By G. I. Madden, L. H. Van Vlack

WhEN basic refractories which contain peri-clase, MgO, are used in steel furnaces, they are altered by iron oxide to form magnesiowiistite, (Mg,Fe)O, and an iron-rich magnesioferrite, (Mg,Fe)Fe2O4. Silica, which is usually present, produces a silicate liquid that surrounds the solid phases. The individual crystalline grains of the above two solid phases grow at elevated temperatures. Previous papersL" showed that, if either periclase or magnesiowiistite is present as the only solid phase, its grain size increases in proportion to temperature and in proportion to the square root of time; the growth rate is reduced slightly if the amount of silicate liquid is increased. Similar results have been observed for iron-rich magnesioferrite.3 To determine the effect of the presence of two solid phases on the rate of grain growth, micro-structural studies have been made on samples containing both magnesiowustite and magnesioferrite. The experimental procedure was the same as that followed in the previous studies of this type.&apos;12 Briefly, this included determination of compositions from the available phase relationships4 that would produce the two phases of interest at the firing temperature and using reagent-grade raw materials to prepare mixtures of these compositions. The mixtures were pressed into pellet-size samples and then fired at the desired time and temperature. The samples were water-quenched to preserve the microstructure present at the firing temperature. Standard reflected-light metallographic techniques were used for sample examination and sample analysis. Grain sizes were determined by measuring the mean diameter of a number of randomly selected grains in a two-dimensional microsection. A large cross section of the sample was covered to prevent biased data resulting from such effects as localized differences in the radius of curvature of the crystal grains. Examination indicates that grain growth is restricted when more than one solid phase is present. This is illustrated in Fig. 1 for: (a) magnesiowustite plus a silicate liquid; (b) magnesioferrite plus a silicate liquid; and (c) magnesiowiistite and magnesioferrite plus a silicate liquid. Fig. 2 plots the

Jan 1, 1964

By Joseph Jensen

California&apos;s outstanding contribution to unit operation is the plan of development now established for the North dome of the Kettleman Hills. Beginning April 1, 1931, the Kettleman North Dome Assn. will control the unified operation and development of 10,800 acres of proven and semiproven oil land, and at the same time the Standard Oil CO. of California will operate as another unit its fee land of 9460 acres of similar character. The holdings of the two companies are in a checkerboard mile-square pattern. In addition to this, 410 acres of land may yet be included in the Kettleman North Dome Assn. unit and 530 acres of land are definitely out of both units. The owners of some of this land have expressed their intention of cooperating in a reasonable way with these two units. Cooperative agreements are now in force as to most of this field. Under the definitions of a unit pool and a near-unit pool,&apos; the operation at Kettleman Hills will be a near-unit operation, but because of the size of the structure and its proven highly productive character, the arrangement. concluded on Jan. 31, 1931, in the approval of the Kettleman North Dome Assn. Agreement by Secretary of the Interior Ray Lyman Wilbur and by California State Oil and Gas Supervisor R. D. Bush is of outstanding importance to the entire oil industry. No other major unit operation plans are under way in California at the present time. There has been some little discussion of a plan in the North Belridge field and a feeling that the discovery of oil in the Lost Hills field and also in the South Belridge field would necessitate consideration of unit plans. So few data are available for these areas, as to the land that should be included in such unit plans, that little constructive action is now possible. The beginning of drilling on the Middle dome of the Kettleman Hills also makes it an area deserving consideration for unit operation. All four of the above-named areas lie on the west side of the San Joaquin Valley, in Kings and Kern counties, to the south of the

Jan 1, 1931