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By David E. Siskind

The Bureau of Mines has studied the fracturing and associated damage occurring in the vicinity of blastholes from five shots fired in the shale pillars in the White Pine copper mine, White Pine, Mich. Four types of explosives (AN-FO, commercial extra dynamite, ammonia gelatin dynamite, and a low-density, low-velocity permissible) were used. Cores were taken from the blast region and examined by ultrasonic and petrographic techniques. Pulse wave velocities were measured across the core diameters, and thin sections showing cracks and changes in lithology were examined in an attempt to establish zones of damage. Cores from the blast regions and areas near pillar free faces were found to have abnormally low pulse velocities. Petrographic study of the thin sections showed that the negative velocity anomalies were caused by cracks in the cores. Crushing and extensive fracturing prevented meaningful measurements on core fragments from the immediate blast vicinities. Compositional, changes and other rock nonuniformities, such as joints and preexisting fractures, tended to mask detailed damage differences among the four explosives; however, the two most energetic explosives (extra dynamite and ammonia gelatin dynamite) produced damage zones two to three times as large as the AN-FO and low-velocity permissible explosives.

Jan 1, 1973

By Leo A. Schrider

A prediction for oil recovery from a pilot waterflood in the Kane oil- field, located in Elk, Forest, and McKean Counties, Pa., was made and compared to actual field performance. Water-injection and production histories, well logs, other field data, and results from laboratory tests of core material were used in this analysis. Performance of the pilot waterflood, initiated in January 1963, was predicted using a modified Craig, Geffen, and Morse calculation technique. Maximum recovery from this low permeable, preferentially oil-wet formation was predicted to be about 22,500 barrels of oil after 300,000 barrels of water had been injected into the pilot waterflood area. After additional field data were collected it became necessary to reevaluate the pilot waterflood area. The gas saturation prior to the waterflood was estimated to have been 20 percent, based on an assumption regarding the required volume of water injected to initiate oil production. In view of the actual field performance, a gas saturation of 13 percent is indicated. When this gas saturation and the method originally proposed by Craig and others are used) the predicted results are more representative. In December 1965, field performance was further analyzed using a hyperbolic-decline curve as presented by Arps. Based upon this evaluation method, the pilot water flood in the Kane sand should produce 37,000 to 42,000 barrels of oil with the injection of 300,000 barrels of water into the pattern. By continuing this secondary-recovery project to a reasonable economic limit, ultimate oil recovery may be as much as 50,000 to 55,000 barrels, or 129 to 142 barrels per acre-foot from 36.5 acres.

Jan 1, 1967

By Dennis E. Bell

"This paper describes exploration and development to 1982 in the southern half of the northeastern British Columbia (Peace River or Northeast Block) inner foothills metallurgical coal belt. Gates Formation, Fort St. John Group, is the primary target; Gething Formation, Bullhead Group, is secondary. This part of the belt remains wilderness when compared to its other parts. Practical formational and structural mapping is described. A local problem known as the Secus Mountain or Mount Belcourt conglomerates is discussed. The three major explorers have been Denison Mines, PetroCanada, and Crows Nest Resources, all with partners. Initial mine construction and rail spur construction are continuing. The new town of Tumbler Ridge is being built. Introduction This paper describes exploration and development to 1982 in the southern half of the northeast British Columbia metallurgical coal belt. The area (Fig. 1) trends 120 km northwest from the Alberta border to the Wolverine River and Bullmoose Creek. The belt averages 15 km in width, and is 20 km at its widest. Physiographically, the area is dominated by rugged inner foothills, with relief to 1,500 m. The trend of the structures is transected by a dozen rivers flowing southwest to northeast away from the Continental Divide. The Rockies, lying immediately to the west, control the climate. One fact continues to colour all coal work in the area. When compared to the other parts of the western Canadian foothills and Rockies coking belt, it remains the least accessible and least mapped portion. Lack of access also makes all work expensive. Current activity centres about two mines in construction at the northwestern end of the area. Denison Mines and partners are developing their Quintette project, and Teck Corporation and partners are developing their Bullmoose project. PetroCanada and partners have intensively explored their Monkman-Duke Mounta,in project, but mine construction awaits better economic times. The rest of the area remains lightly explored, with the exception of some intensive work on particular structures by Denison and Petro-Canada. The focus of coal work has been metallurgical bituminous coal seams contained primarily in the Gates Formation (Fig. 2) and secondarily in the Gething Formation. These formations are found in generally en-echelon structures ranging to several kilometres in width."

Jan 1, 1985

By I. Martinez-Dominguez

In September 1992, mining in Mexico was opened again to foreign investment by President Salinas-de Gortari, after thirty years of "Mexicanization" of mining industry which limited foreign participation up to a 49 % (or 34 % in case of national reserves) on a Mexican mining corporation. During said period mining in Mexico was controlled by four or five big mining companies and besides mining production was focused mainly on silver, lead, zinc, copper and fluorspar. Suddenly in middle of a big crisis on Mexican mining industry due to low prices of minerals in the world and also in a period on which it seems that mining industry in the United States and Canada has been condemned to die for environmental reasons, it appears a new Mexican Mining Law to permit foreigners to participate in mining in Mexico' trough Mexican mining corporations that they may control up to 100 %

Jan 1, 1994

By G. I. Mathieu

Research and development studies were carried out at the Canada Centre for Mineral and Energy Technology to produce a synthetic forsterite sand from asbestos tailings for Les Sables Olimag Inc. The National Research Council of Canada also supported and collaborated to the project. Theoretically, the technological approach consists of a heat at over 1300°C; however, the process without additive would result in the production of an enstatite-rich product (MgSiO3) having a fusion temperature less than 1600°C. The purpose was to foster the formation of forsterite (Mg2SiO4), a more refractory compound. The fabrication of the forsterite product requires pre-agglomeration of serpentine-MgO with a binder, which is stable at high temperature, to prevent the loss of the powdered magnesium oxide as dust in the kiln off gases and to maintain the mixture homogeneous during the process. Characterization of the end products with respect to mineral composition and thermal resistance are described. The synthetic forsterite in sand form was tested with success under a bath of liquid steel maintained at 1700°C for up to two hours. The advantages of the new sand and its potential applications will be reviewed.

Jan 1, 1992

By G. B. Harris, C. W. White

Cyanide has been used for the recovery of gold since the mid 1800s, but several jurisdictions have already banned its use, and environmental pressures are increasing to finding an alternative. Gold also forms chloride complexes similar to those of cyanide, but the use of chloride has never achieved widespread acceptance. This paper describes a chloride-based flowsheet, wherein the key unit process is the recovery and recycle of chloride ion. It is shown that the chloride-based flowsheet is competitive economically with the conventional cyanide-based flowsheets, and that it has a number of other advantages, particularly environmentally.

Jan 1, 2011

By C. J. Newman, K. Molnar, A. G. Storey, G. Macfarlane

"The Kidd Creek copper smelter started operation in June 1981 using the Mitsubishi Continuous Smelting Process. A steady increase in plant production rates has been demonstrated, and the annual tonnage of concentrate smelted is now double the original design rate. This paper summarizes recent modifications made to increase concentrate feed rates, increase on-line time, reduce copper losses and control the impurity level in anode copper. It includes improvements made to furnace design, improvements to reduce downtime f or boiler cleaning, and improvements made to the acid plant to allow handling of increased gas flowrates and higher gas strengths while maintaining low acid plant emission rates. IntroductionThe Kidd Creek Division of Fal conbridge Limited operates a base-metal mining and metallurgical complex, located in Timmins, Ontario, which includes an underground mine, a 13 500 tonne/day concentrator, a 130000 tonne/year zinc plant and a copper smelter and refinery, The copper smelter and refinery were commissioned in 1981, with an installed capacity of 59 000 tonnes/ year of cathode. The smelter, utilizing the continuous smelting technology of the Mitsubishi Process, has subsequently been expanded in production capacity, and in 1991 produced 113 500 tonnes of blister copper The capacity of the refinery, which uses Onahama No. 3 tankhouse technology, has been increased to 96 000 tonnes/year of cathode. The capacity increase at the smelter has been realized through the input of additional oxygen to both the smelting and converting furnaces, without increasing the process off-gas flowrate through the associated waste heat boilers.In this paper, a brief review of smelter operation and modifications in the period 1982 to 1987 is presented, together with a more detailed discussion of operation during 1988 to 1991, and a discussion of future planned improvements."

Jan 1, 1992

By J Seppelt, B Akerstrom, J Bubnich, D Seaman, T Waters

The Cadia Hill concentrator at Newcrest’s Cadia Operations has undergone several modifications and upgrades to treat an increased throughput rate of harder ore from the Cadia East block cave mine.Subsequent to the commissioning of the expanded circuit, the flotation cleaner block has undergone a systematic optimisation programme tackling all facets of circuit operation. This included debottlenecking circuit constraints and installation of Jameson cell technology to enhance copper and gold recovery while rejecting fluorine and gangue from the concentrate.This paper outlines the improvements over the course of the project and results obtained from the implemented actions.CITATION:Akerstrom, B, Seppelt, J, Waters, T, Bubnich, J and Seaman, D, 2018. Cleaner circuit optimisation at Cadia Operations, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 457–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Peter Hayes, Evgueni Jak, Taufiq Hidayat, David Grimsey, Denis Shishin

"An integrated nickel flash smelter is operated with Peirce-Smith converters at the Kalgoorlie Nickel Smelter. To improve the partitioning of arsenic between slag waste and matte product, an option to modify the slag–matte chemistry by addition of CaO was analysed. A combination of plant sample analysis, high-temperature laboratory experiments and thermodynamic modeling was carried out to evaluate the process options. The high-temperature experiments involved the re-equilibration of industrial matte-slag samples at 1225 °C and P(SO2) = 0.12 atm, rapid quenching in water, and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LAICPMS). A private thermodynamic database for nickel sulfide smelting and converting was used together with the FactSage thermochemical software package to assist in the analysis of the distribution of elements between slag and matte as a function of CaO addition. The thermodynamic predictions combined with experimental data obtained in this study can be used to characterise the effect of CaO fluxing on the slag–matte thermochemistry during the nickel sulfide converting.INTRODUCTION At the Kalgoorlie Nickel Smelter (KNS), nickel sulfide concentrate is processed in an Outotec-type flash furnace to produce nickel matte containing +47 wt% Ni. Separation of nickel matte and waste slag from the flash smelting is enhanced through settling in the electric arc -heated zone attached to the flash furnace. The flash furnace matte is further processed in a Peirce-Smith converter to produce Ni-rich matte containing +66 wt% Ni (Crundwell, Moats, Ramachandran, Robinson, & Davenport, 2011). Iron silicate-based slag is used in the converting process at KNS. Most of the arsenic is contained in the final matte and very little of the arsenic partitions into the slag. Previous work by Font et al (Font, Hino, & Itagaki, 2003) shows that the distribution ratio of arsenic between calcium ferrite slag and nickel-matte (LAsslag/matte) is significantly higher than that between iron silicate slag and nickel-matte, where LAsslag/matte = (wt pct As in slag)/{wt pct As in matte} (1)"

Jan 1, 2017

By L. W. Rowe, S. S. Cole

A laboratory bench scale unit is described whereby finely divided chlorinatable residues are held for a short period by a restraining bed of a coarse-grained ore of comparable composition to permit 'flash' chlorination of the high surface area powder. Results on chlorinating a finely divicled titania residue using rutile sand as the restraining bed showed that 92 pct utilization of chlorine and equivalent conversion of TiO2 in the fine residue to Ticl4 were attained with a dust loss of about 3 to 4 pct and an equivalent amount of ch1om'nation of the titanium values in the restraining bed. THE chlorination of coarse grain titaniferous ores; i.e., 20 to 150 mesh sizes in fluidized beds is practiced commercially.' One effective method found for the chlorination of a very fine material in a fluidized bed is the "flash" chlorination technique.' By charging the finely divided charge material into the bottom of an established bed of optimum sized rutile, ilmenite, titanium beneficiate, or even an inert material such as sand, chlorination occurs before the dust can pass through the bed. The major requirement is that the bed be less chlorinatable than the charge. In this process, the charge consists of a finely divided (between one and 50 µ) titania residue obtained from a titaniferous ore beneficiation process. The charge is blended with a 20 pct wt basis addition of 20 to 60 .mesh size low volatile coke (to minimize hydrogen chloride formation) and fed to the bottom of the bed with the chlorine gas stream. A ball check device is used to permit entry of the charge and prevent the bed from discharging when the gas flow is cut off. The coarse pieces of coke serve to reduce compaction in the charge mixture and permit sat]sfactory feeding without plugging or jamming. Feed and gas rates are adjusted to provide for complete reaction of the charge material, with 90 to 95 pct chlorine efficiency, and maintain a gas flow in the range of 0.4 to 0.6 ft per sec. The equipment consisted of a 3-in. diam mullite tube enclosed in an electric furnace. A bow-shaped 3/4 in. Saran tube fed the charge from an air lock type of feed hopper (to prevent the escape of the chlorine gas into feed bin) to the bottom of the bed. The charge rate was set by providing a small awiliary hopper below the feed hopper where a weighed portion of the charge could be discharged in a specified time interval into the main chlorine stream. The chlorine rate was measured by a flowmeter. The reaction tube was filled with a bed of Australian rutile ore, this restraining bed serving two purposes; i.e., it rapidly heated the fresh charge to the reaction temperature and retained the particles in the bed for a sufficient time for selective chlorination to proceed. Due to the fine particle size and open, porous structure of the charge, this reaction was almost instantaneous, and, with proper adjustment of feed and gas rates, very little fine material passed through the bed without reacting and only a very small fraction of the restraining bed was chlorinated. A typical reaction procedure was to fill the bench scale fluidized bed unit with a 1 kg charge of Australian rutile ore analyzing 95.5 pct TiO2, 0.6 pct FeO, a beach sand deposit 40 to 150 mesh size. When fluidized, the bed was approximately 2 ft in depth. The ore was fluidized with a 1:l mixture of chlorine and nitrogen at a rate of 0.40 ft per sec. This gas mixture was necessitated by the comparatively short bed depth; a larger unit, with a deeper bed, could be fluidized with chlorine alone without significant free chlorine loss. Feed rate was 8.0 g per min of beneficiated ilmenite analyzing 85.0 pct TiO2, 2.6 pct FeO plus 1.6 g per min of 20 to 60 mesh petroleum coke. The

Jan 1, 1962

By Léo Daiki Shinomiya

O trabalho apresenta estudos de cenários técnico e econômico para a implantação de uma pequena fábrica cerâmica, através do estudo de caso de uma prospecção de argila vermelha no interior do Pará. O estudo consistiu na execução de sondagem à trado (ST) na área, para cálculo volumétrico da reserva, e recolhimento de amostra para caracterizações em laboratório. A argila coletada foi submetida a análises do teor de umidade, química (Fluorescência de Raios-X) e mineralógica (Difratometria de Raios-X). Um cenário para uma empresa entre micro e pequena produtora de cerâmica foi estabelecido visando estimativas preliminares para um possível empreendimento. A análise de cenários levou a uma possibilidade de implementação de uma unidade fabril de cerâmica com capacidade produtiva de até 140 mil peças/mês. Restrições quanto ao tipo de produto desejado e a característica da argila prospectada devem ser consideradas, podendo ser necessário a mistura de argilas de base “gorda”, com maior quantidade de argilominerais.

Aug 17, 2017

By Michael S. Wieland

This report investigates whether it is tractable and thereupon reasonable to remove the booster influences when ranking the toxic fumes of non-cap-sensitive mining explosives. The hazard potential is represented by relative fume toxicity RFT, the resultant influence computed from a formulated rule with a restricted set (tally) of fume components and multiplying constants. The RFT result is compared to the rule criterion that represents the worst case tolerable toxicity stipulated by regulations or otherwise. The typical nonstoichiometric booster composition can render notable unwanted influence on the RFT ranking results. Historically, the remedy was to shoot the booster separately and reduce the trial concentrations by the relevant subtractions. Unreal negative concentration results were noted on rare occasions, revealing the faulty nature of the reduction procedure. With thermodynamic reaction chemistry codes TDRC, on the other hand, the booster ingredients can be retained in or removed from the reactant tabulation, yielding reduction factors taken as the concentration ratios for the two circumstances. The underlying presumption regarding reduction factors is that the ratios of component concentrations with and without the booster ingredients when resolved theoretically ought to equal those rendered experimentally, when tractable. Upon rearranging the presumed relationship, the unadjusted fume concentrations divided by theoretical reduction factors yield the wanted readjusted fume concentrations, thereby removing the booster influence without generating unreal negative concentrations. The work principle from thermodynamics restricted by the constraint of zero-net interaction loss is utilized in conjunction with the TDRC to resolve the wanted (Z-state) fume spectrum. This circumvents the recognized difficulty with traditional hydrodynamic detonation theory that is related to the nonideal reaction characteristics of typical mining explosives. The tacit characteristic of the Z-state resolved from the non-trajectory work principle is that it can not be remedied or tampered with, unlike the traditional trajectory techniques where the reaction products can be readjusted by changing formula representations, nullifying specific reactions or otherwise manipulating the thermodynamic trajectory process. Though the work principle theory is an unfinished formulation, the Z-state results prove worthy enough for rendering trends and comparisons and reaching otherwise useful conclusions. Further refinements should yield more reliable fume spectra and indicate explosive composition readjustments that would reduce toxic effects within underground mines and the wider world environment.

By Thomas E. Finch

Engineering mine design encompasses a range of situations, and each situation has its own range of detail and fineness. The most time consuming, and perhaps repetitive design situation involves evaluation of new or alternate mining methods. Many man years are consumed examing alternatives conjured up at all levels of the design team, from the number crunching engineer to the engineering manager. Many alternatives are intuitively disregarded, some are briefly evaluated and thrown out, and many others are started but not completed due to time constraints. All alternatives have similar input characteristics and evaluation procedures. In the design process, production requirements are known and equipment production capabilities are generated to determine the numbers and costs of an equipment type required to match a given situation. The end result is some comparative figure, typically cost per ton or yard upon which a decision is built. The similarity of input data and problem solving techniques lends design to computer solution. Computer aided equipment evaluation is not new to the mining industry. An existing and accepted technique is exemplified with the programs used by truck manufacturers. Given a haulage profile and production requirements, the number of anyone capacity, horsepower, tire size, gear ratio or similar characteristically identified truck can be determined. This information can be outputted in varying degrees of complexity and the results used with equally varying percentages of credibility by design or production engineers. Most engineers are willing to accept-the computer's effort with relief and a desire for belief. Although inherently more complex, the ultimate end of computer manipulation should be total mine design. This is an extremely large step in the evolution of mine design, and not many engineers, including the authors, believe the results would be directly applicable or necessarily correct. As with computer simulations of an operation, total computer design of mines requires such complex and lengthy input that each mine might be manually designed more quickly and cheaply. The existence of computer programs which initially evaluate a mining system or part of the system is upon us, however.

Jan 1, 1978

PRESIDENT. CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS. CHARLES KIRCHHOFF,1 NEW YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT. BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER. GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS. ROSSITER W. RAYMOND NEW YORK, N. Y.

Jan 5, 1913

By S. T. Wlodek

The scale md subscale reaction products were identified and their rates of formation were studied in air over the range 1600" to 2000°F (871 " to 1149°C) for periods of up to 400 hr and for hoth the solution-annealed and aged conditions. The effect of prior sltrface preparation on suhscale oxidation was also studied The general oxidation behavior of both Ni-Cr-Mo-Al-Ti type alloys was similar. A surface film of a, Al2O3, forms immediately on exposure Subsequent oxidation continued at a linear rate (QL = 55 * 5 kcal per mole) as colonies of Cr2O3 nucleated at the A12O3/gas interface Further oxidation proceeded at a paraholic rate zvhiclz could he fitted to two successive rate constants. During paraholic oxidation, and depending on temperature, the scale consisted of Cr2O3, NiCr2O4 , and TiO2 with traces of NiO. In the case of Rene 41, the activation energy of both paraholic processes was 66 * 3 kcal per mole suggesting that diffusion of cations tlzrozrgh Cr2O3 was the rate -determining process. An unusual decrease in the oxidation of Udimet 700 at 1900°F where a spinel of Ni(A1,Crh0, zuas the predominant reaction product prevented the accurate assignment of activation energies for this composition. In both alloys internal oxidation of Al2O3 commenced shortly after parabolic scaling was observed. Prolonged exposure prod7tced intemal oxidation of TiN, and in Udimet 700 a complex Mo-Ni nitride was also found. At 1900oF, the subscale reactions in Udimet 700 undergo an inversion which parallels the decrease in surface oxidation; internal oxidation ceases hut is replaced by the formation of "spherodized" 3.' colonies. Surface-preparation techniqtles which introduce appreciable working, such as coarse surface grinding or grit blasting. increase the amount of alloy depletion and internal oxidation in Reni 41. The reverse is true of Udimet 700 for which electropolished or mechanically polished specimens show much more subscale oxidation than strongly worked stirfaces. The strongest commercial nickel-base alloys presently available are generic to the Ni-Cr-Mo-A1-Ti base which exploits the precipitation of Ni3(A1,Ti) as the main strengthening mechanism, while relying on solid-solution strengthening by molybdenum and chromium reinforced by the pre- cipitation of carbides to attain maximum properties. This study characterizes the oxidation behavior of Rene 41, the strongest alloy of the Ni-Cr-A1-Ti type commercially available in sheet form, and Udimet 700, whose higher aluminum and titanium content allows it to exhibit one of the more attractive combinations of high-temperature properties available in a wrought product. The scaling processes of complex, type nickel-base alloys have received relatively little attention. Malamand and vidal as well as Poulignier et al.2'3 have determined the composition gradients across the metal/oxide interface produced by high-temperature oxidation and considered the effect of surface perature, Limited weight-gain data has also been published by Fere 5 for alloys of this type and Radavich6 has identified the reaction products on Udimet 500 and Inco 702 after oxidation at 1832°F. Reference can, of course, be made to the excellent reviews of Kubaschewski and Hopkins7 or Ignatov and Shamgunova8 for a summary of the data available on the oxidation of binary and ternary alloy systems which are related to the more complex alloys considered here. EXPERIMENTAL The analyses of the different commercial heats studied are given in Table I. Using the experimental procedures previously established,9 continuous weight-gain data were obtained on both heats of Rene 41 sheet (A and B) and 150-mil-thick slices of cast Udimet 700. Subscale oxidation reactions were followed by static exposure of cylindrical specimens obtained from swaged Rene 41 (Heat C) and Udimet 700 (Heats E and F). In brief, continuous weight-gain tests were performed on specimens with a surface area of 10 to 12 sq cm. These were abraded through 600 grit Sic paper, electropolished to 2p rms in an electrolyte of 10 pct H2So4 in ethanol, and lightly etched in 10 pct HCl in ethanol before final washing and rinsing in ethanol. All continuous weight-gain data were obtained in dried (-70°F dew point) flowing (1 liter per min) air to an accuracy of +0.1 mg. Subscale oxidation processes were followed by the metallographic examination of 0.5-in-diam by 1.0-in.-long specimens. After an initial center-less grinding, various additional surface treatments were employed to determine the effect of surface preparation on subscale oxidation processes. Before exposure in zirconia crucibles, all samples were lightly etched in 10 pct HCl-ethanol, washed in ethanol, and dried. The depth of internal oxidation was measured to ±0.00025 in. on unetched specimens mounted so as to provide a taper mag-

Jan 1, 1964

By James Spiers

This paper describing the mining practice at the Central-Eureka mine is one of a series of similar papers being prepared by the United Staten Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described in this paper are illustrative of the methods employed in the exploitation of comparatively low-grade gold ores under the extremely heavy and swelling ground conditions which occur in the Mother Lode belt of California. The Central-Eureka Mining Co. comprises a group of adjoining mines in Amador County near Sutter Creek. The principal mines of the consolidated group are the Central-Eureka, formerly known as the Summit mine, and the Old Eureka mine, which is also known as the Hayward Quartz mine. The group is situated in the most productive part of tae main Mother Lode belt, the 10-mile portion which lies between the towns of Plymouth and Jackson. The three largest producing mines of the entire belt at the present time are the Argonaut, Kennedy, and the Central-Eureka; these lie within a radius of less than 1-1/2 miles.

Jan 1, 1931

By William H. Waggaman

The United States not only is the largest producer of phosphate rock but also manufactures and consumes greater quantities of phosphate products than any other country. New and expanding uses will increase even further the demand for this basic raw material. Only a small proportion of the total quantity of phosphate rock mined and marketed is consumed directly in a raw or unprocessed state; the vast bulk is chemically treated and converted into [ertilizer] and a wide variety of finished products that play a vital role in [r] national economy. Three fundamental methods are employed in decomposing phosphate rock. 1. Reduction by carbon at high temperatures. 2. Treatment with one or more acids. 3. Calcination or fusion with silica, sodium salts, magnesium minerals, or small quantities of phosphoric acid.

Jan 1, 1960

By John O. Atkins

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

Jan 1, 1974

By Joseph F. Davies

Along with the humanitarian need for preventing accidents the cost of injuries must be considered. As a means of bringing the facts concerning the prevalence of accidents in mining and their direct cost before the operating officials and others interested in accident prevention in the mining industry, the United. States Bureau of Mines ha as recently made studies and published reports dealing with these subjects in several States 4. This report gives available data on the causes and direct costs of accidents in Virginia coal mines for the 4-year period 1929 to 1932, inclusive. Mounting compensation costs and insurance rates resulting from mine injuries indicate the necessity of measures to decrease the number and severity of accidents. These direct costs, as well as additional losses of an indirect nature, can be eliminated from the cost of production to the extent that accidents are prevented or reduced in severity.

Jan 1, 1934

By Wayne N. McKee, Scott A. Lewis

"Introduction to the Syncrude OperationSyncrude Canada Ltd., located 42 km north of the city of Fort McMurray, Alberta, (Fig. I) is an integrated operation that has produced synthetic crude oil from the Athabasca oil sand deposit since 1978.The operation, consisting of a surface mine, an extraction plant, a bitumen upgrader, and a utilities plant, is currently capable of producing over 60 million barrels of crude oil per year. Production is expected to increase to 70 million barrels of crude oil per year over the next five-year period with no major changes to equipment or process planned.The Syncrude surface mine, producing a total of 675 000 tonnes of ore and waste per day, rates as one of the largest mines in the world. A strip mining method is utilized, with two or three operating benches necessary to excavate a total depth varying between 60 m and 70 m. The 20 m to 30 m of overburden is removed by electric and hydraulic shovels and 200-ton haul trucks, and dumped in the mined-out pit for final storage. The overburden operation creates a flat bench near the top of the ore zone on which the four 60 m3 draglines operate. The draglines excavate interbanded ore and waste in the highwall, with ore placed on the operating bench in windrows, and waste returned to the mined-out pit. The windrowed ore is reclaimed by four bucketwheel reclaimers, and discharged onto a conveyor system for transfer to the extraction plant."

Jan 1, 1993