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By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By Dorsey Hager

NORTH -CENTRAL Texas has recently become a center of interest for the oil men of America. The bringing in of the McClosky well at Ranger, Eastland County, and the shallow pool at Brownwood, Brown County, in 1917, has stimulated interest in this area to fever pitch. Oil men from all over the United States are now investing there. The area of present interest is shown by the accompanying map (Fig. 1). The money spent in leases runs into millions of dollars. It is no exaggeration to say that a strip of country 200 miles (321 km.) long and 125 miles (201 km.) wide, comprising some 15,000,000 acres (6,070,310 ha.)., has been leased practically solid at a cost for rentals and bonuses of at least $1 per acre. The test holes contracted for will certainly number 400, at a cost of at, east $5,000,000. From what has been done in the past six months, $20,000,000 at least will be spent. To pay, returns on this amount of money, new production to the extent of at least 12,000,000 bbl. must be obtained. At present, the production from new fields will not average over 5000 bbl. per (lay; three wells at Ranger are producing 3000 bbl.; 250 wells at Brownwood produce 1000 bbl.; and the Gray well, Coleman County, is as yet an unknown factor. However, at Ranger there is every indication of developing a good pool covering from 1500 to 2000 acres (607 to 809 ha;), more or less, but the wells are deep, 3400 to 3800 ft. (1036 to 1158 m.), and cost $35,000 to $40,000 to drill. Large wells are necessary to pay for such expensive holes. As new wells are drilled, the gas pressure will be lowered rapidly, and large production need not be expected. For those oil men who expect a second Cushing or an Eldorado, Ranger holds little of promise. At Brownwood, Brown County, there are some 250 shallow wells (depths from. 200 to 350 ft.) averaging 4 to 7 bbl. per day. There is a chance of an extensive producing area, for these shallow sands to the southwest, and the opening of several thousand acres of shallow oil territory, and also some promise of deeper oil horizons in the Ranger horizon, but probably all under 2500 ft.

Jan 6, 1918

By S. V. Balikov

A close association of fine gold with pyrite and arsenopyrite is observed at many gold ore deposits. Gold forms and gold distribution in sulfides of different deposits were studied. A comprehensive method including optical spectrum analysis, X-ray diffraction analysis, high-temperature X-ray diffraction analysis, scanning electron microscopy and X-ray microanalysis was used for the de-tailed investigation of the defectiveness of the structure of pyrites from different deposits. It was shown that gold content in pyrites varied from 1.5 g/t to 100 g/t compared with 30 g/t to 230 g/t in arsenopyrites. The nature and arrangement of inner inclusions of foreign minerals in pyrites as well as occurrence of fractures and macro- and microdefects were examined. Iron, sulfur and arsenic contents in all pyrite samples were determined. Chemical composition of the detected inclusions was defined. Parameters of submicroscopic structure of pyrite were estimated using X-ray Fourier line shape analysis. Estimation of real structure characteristics with calculation of submicroscopic D-blocks and root-mean-square lattice deformation 2()evalues was performed. Defectiveness of the pyrite structure can be defined by the following parameters: K?1 and K?2 reflection resolution and its intensity within high Bragg angles; S content to Fe content ratio; the arsenic content and the local variation in its concentration within the pyrite grain; the size of submicroscopic blocks and the crystal lattice disturbance value. The performed analysis showed some relationships between these parameters and refractoriness of the pyrite concentrates. It was observed that at S/Fe ratio close to or higher than stoichiometry and at a low arsenic content (less than one per cent) pyrite concentrates were not refractory. The analysis results showed that concentrates of the Beryozovskaya gold plant (0.02~0.07 As%) and concentrates of the Kommunarovskaya gold plant (less than 0.05 As%) as well as some pyrites from the Sukhoi Log gold deposit had the same characteristics. It was found that average arsenic content did not excess 0.2 per cent. Arsenic distribution within the grain of all these pyrites was uniform. At S/Fe ratio lower than or close to stoichiometry and at high arsenic content (more than one per cent) and significant variation in its distribution within a pyrite grain the pyrite concentrates are refractory. Such pyrites are typical for the Sukhoi Log, the Bakyrchik and the Mardzhanbulak gold deposits. Direct correlation between arsenic and gold contents, in particular, in fine grains of pyrite was observed by many researches. This correlation was explained by impregnation of arsenopyrite which normally contains more gold than arsenic pyrites. The analyses results showed that no arsenopyrite impregnation was found: arsenic distribution within the grain was uniform but its concentration varied greatly. Such pyrite concentrates are more refractory. This paper presents the results of analyses of sulfides to determine the amenability of the associated gold recovery by hydro- and pyrometallurgy.

Jan 1, 2014

By B. K. Larkin, H. K. van Poollen, H. C. Bixel

A detailed treatment is given of the transient pressure behavior of a well located near a linear discontinuity. On either side of the discontinuity, the values of permeability, viscosity, compressibility, and porosity are uniform, but may be different from those on the other side of the discontinuity. These results generalize previously published works which assumed the permeability ratio for media on different sides of the discontinuity was zero, one, or infinity. One application of this material would be to facilitate detection of facies changes or fluid-fluid contacts by transient testing. Solutions, presented graphically, show pressure decline for constant rate fluid production. The range of variables examined includes dimensionless time from 0.1 to 100, rnohility ratio from 0.001 to 1000 and specific compressibility ratio from 0.001 to 1000. For dimensionless tinze less than 0.4, the pressure behavior is essentially that of a well in an infinite reservoir. Thus, reservoir properties near the well may be estimated in the usual manner. Using an overlay technique to match an experimental curve with one of the theoretical curves, it is possible to estimate the distance to a discontinuity by substituting the actual time t and the corresponding dimensionless time , at which a match occurs into the equation where is the diffusivity near the well, and may be estimated from data taken at early time. Because of both the complexity of the solutions and limited computer facilities, well interference problems were not examined extensively. However, it was found that well interference may be masked by the discontinuity in some cases. By superposition of the results of constant rate fluid production, the problenz of pressure buildup may be treated. Such results show that for early shut-in times correct values for the transnzissibility are obtained from conventional semilog plotting. However, erroneous values of the static reservoir pressure are obtained unless data at large shut-in times are taken. INTRODUCTION Transient well testing has yielded estimates of such reservoir parameters as static reservoir pressure, permeability. porosity, and well bore effects. In most tests, it was assumed that the reservoirs were homogeneous and iso-tropic. Anisotropic media' and radial discontinuities were considered.'.' Various studies have been made on multiple-layer reservoirs." ' Linear discontinuities have been described for problems of one-dimensional flow.' In the present paper, a mathematical treatment is given for a well located near a linear discontinuity in an otherwise infinite medium (see Fig. 1). An actual reservoir analogy would be a well in a relatively thin reservoir near a fluid-fluid contact, or a well located in a reservoir exhibiting a sudden change in rock and formation characteristics, such as thickness, porosity, or permeability. A sudden change in porosity or permeability may be caused by clay fill or other types of facies changes. Sudden thickness changes niay be the result of such geological formations as buried shore lines and channel deposits. In otherwise uniform formations, a linear discontinuity may be caused by fluid-fluid interfaces such as oil-water contacts. 3s-oil contacts, or gas-water contacts.

By J. D. Zhou, F. Yang, X. G. Bi

"In this investigation, the phosphorus distribution ratios in the CaF2 system and B2O3 system dephosphorization slags for high-phosphorus hot metal pretreatment were measured by an indirect method under laboratory conditions. Firstly, the phosphorus distribution ratio between liquid slag and solid iron was measured, and then the phosphorus distribution ratio between liquid slag and hot metal was calculated. Phosphorus capacity was calculated in terms of the composition and optical basicity of the slag. Dephosphorization slag was also studied by scanning electron microscopy, energy dispersive analysis, and X-ray diffraction analysis. The experimental results show that the phosphorus capacity of the B2O3 slag system is much greater than that of the CaF2 system. It is demonstrated thatB2O3 can completely replace CaF2 as fluxing agent for high-phosphorus hot metal pretreatment. With CaF2 as fluxing agent, the phosphorus capacity increases with increasing CaO content in the slag, but the phosphorus distribution ratio decreases. B2O3, when used as fluxing agent, can react with high melting point phases such as 2CaO·SiO2 and 3CaO·P2O5 in the slag to form new phases with low melting points such as 11CaO·B2O3.4SiO2, 2CaO·B2O3.SiO2, and Ca9.93(P5.84B0.16O24) (B0.67O1.79), thereby acting as a fluxing agent. When the ratio of w(B2O3)/w(CaO) is 0.16, the phosphorus distribution ratio reaches its maximum value, that is, the dephosphorization ability of the slag is at its maximum. IntroductionAs international iron ore prices continue to rise, the development of China's steel industry is facing a lot of pressure. Against this background, development and utilization of domestic high-phosphorus iron ore resources is particularly important. When highphosphorus iron ore is used in ironmaking, the phosphorus content in the hot metal can reach 0.35% or more, and the hot metal must be pretreated. For hot metal with 0.08–0.10% dissolved phosphorus, the traditional hot metal dephosphorization pretreatment technologies are relatively mature. However, when using these methods to dephosphorize hot metal containing 0.35% P or more, the amount of dephosphorization slag can reach 100–150 kg per ton of hot metal. Furthermore, the traditional dephosphorization methods require the addition of large amounts of CaF2 as fluxing agent, and this results in high fluoride levels in the dephosphorization slag. The fluorine in the slag can partially dissolve in water and thereby causes high fluoride concentration in the water and soil. Once the fluoride is absorbed by humans or animals, it can result in toxic effects on the central nervous system and myocardium. In addition, fluoride can accumulate in the environment, and thereby pose a health risk to animals and humans through the food chain (Li, 2007; Liu, Wang, and Dong, 2011, Diao, 2013). The objective of this research is to replace CaF2 with B2O3 as fluxing agent while achieving the expected goals of hot metal pretreatment."

Jan 1, 2016

By J. D. Cooner

SINCE my working life of 32 yr has been spent in and about the anthracite mines of the Hudson Coal Co., and the previous 4 yr in a college school of mines, I can write best about the safety program of a coal mining company. However, most of the suggestions, statements and practices mentioned herein are applicable to the members of a safety organization and program of almost any industry. It is realized that industrial officials actually interested in real safety work are fully acquainted with the requirements of a practical safety program. Therefore, for such persons there may be nothing new in this paper. The Hudson Coal Co. of Scranton, Pa., employs 7,000 men and produces 5,000,000 tons of anthracite annually at nine collieries scattered for a distance of 40 miles throughout the Lackawanna and Wyoming valleys of northeastern Pennsylvania. For the past 17 yr of the above mentioned 32, I have been engaged in safety work as a safety inspector, assistant mine superintendent, and at present the safety engineer. I have also had the privilege of visiting coal and metal mines in other parts of the United States and Canada. We Americans are the most careless people in the world. If any one doubts this statement why are 100,000 of our people killed accidentally annually? Or why during the almost four years we were engaged in World War II were more of our people killed accidentally at home than were killed in our army, navy, marine corps, coast guard, and other services during the same period? We are careless everywhere in our homes, on the highway, at work and at play. The purpose of this paper is to outline the requisites of a safety department and its program to stop the accidents occurring to employees at work in mines or industrial plants. The first requisite for a safety program is that the management must be convinced of the need and value of a real safety program. By "management" is meant each department head from the president down. Otherwise a good safety department with a good safety program will not succeed because it will not have the proper personnel and equipment to work with, its rules and regulations will not be enforced, and the members of the safety department will be belittled in the eyes of most of the workmen and supervisors. Next, a safety engineer and his inspectors should have worked in the production end of the mines as workmen and also in an official capacity. They are then in a position to have practical and first hand knowledge of the accident hazards of the industry, how to prevent them, and in general the problems of both the workmen and officials. Some men are appointed as safety inspectors when they are physically unable to carry on as mine officials. Such men may know the safety end of the industry and even be safety-conscious, but if they are physically unable to be mine officials they are also physically unable to be safety inspectors, as a safety inspector in our mines must walk from 2 to 4 miles on each daily inspection-and visit each working

Jan 1, 1948

By A. S. Odeh

This paper analyzes the effect of limited entry to flow at the wellbore on the steady-state productivity of a well. Wells that have been opened to flow along a fraction of their productive interval are termed wells with limited entry. Previous work treated the cases of a partially penetrating well, a well producing from the central portion of the productive interval and a well in which several intervals equally spaced were open to flow. In this paper the open interval can be located anywhere within the productive interval. Thus, in a sense, it generalizes previous work. The finite cosine transform was used to arrive at a solution for steady-state flow of a slightly compressible fluid. The solution was programmed for a CDC 1604 computer. Numerical vaIues for rd = 660 ft, r, = 1/4 ft, and range of sand thickness of 20 to 200 ft are presented in graphical form. The effect of rd and r, values on the result is shown in a table. The correct calculation of skin and damage ratio in the presence of limited entry to flow is explained and illustrated by examples. Moreover, the paper shows how to calculate the net decrease in productivity due to the combined effect of limited entry and perforations. INTRODUCTION In some wells only a fraction of the productive interval is open to flow. Location of this fraction is usually dictated by formation characteristics and reservoir behavior. For instance, if a gas cap exists, the open interval is located away from the gas-oil contact to prevent any possible gas coning. Wells that intentionally have been opened to flow along a fraction of their productive formation are tened wells with limited entry. Obviously, unintentional completions of this type also exist. Limited entry to flow decreases well productivity. Magnitude of the loss depends on the fraction of the formation open to flow, on the thickness of the sand, on the location of the open interval and on the ratio of rd /r, where r , is well radius and rd is the drainage radius of the well. The use of pressure buildup data on producing wells to calculate the condition of the formation around the wellbore is an accepted practice. van Everdingenl and Hurst2 introduced the concept of she skin factor s considered to be due to a thin layer of different permeability immediately around the wellbore. These authors dealt with the case of a well of complete radial geometry, i.e., a well with open-hole completion that completely penetrates the formation. The presence of a low-permeability skin results in a loss of productivity, as does limited entry. Therefore, if pressure buildup data obtained on a well with limited entry are used to establish the presence or absence of skin (i.e., formation damage), and a correction is not made for this loss of productivity, the calculations would result in an erroneous skin value. They might indicate the presence of formation damage when in reality there is none, or they might indicate a value larger than the true value. This could lead to an incorrect basis for planning remedial measures. Muskat3 studied the problem of partially penetrating wells for the case of incompressible flow. He presented equations and figures which allow estimation of loss in productivity. Brons and Marting,4 using equations based on Nisle's work,5 studied the loss of productivity for three cases. The first was for a partially penetrating well; the second was for a well producing from only the central portion of a productive interval; and the third was for a well in which several intervals equally spaced were open to flow. Their work was for steady-state depletion-type reservoirs wherein the well radius of drainage is established and the fluid is considered to be slightly compressible. Considered in this paper is the problem of wells with limited entry in which the open intervals are located anywhere within the productive sand. The finite cosine transform is used to arrive at a

Jan 1, 1969

By D. Eriksen

Zero Emission Gas power, ZEG, is a novel concept where a high temperature solid oxide fuel cell (SOFC) is integrated with a reforming reactor producing hydrogen from natural gas through Sorption Enhanced Steam Methane Reforming (SESMR). The SOFC is used as a high temperature heat source for regeneration of the CO2-absorbent. Moreover, by using part of the produced hydrogen as fuel for the SOFC, the waste heat of the process is considerably reduced. Thus, the process has a very high thermal efficiency and produces both electricity and hydrogen from natural gas. In addition, a stream of pure CO2 is produced in the regeneration step and can be deposited or used commercially. Initial cost estimates indicate a cost of electricity and a cost of hydrogen well below today's prices. A small (1kWel + 1kW H2) demonstration set-up is under construction and experimental results and related research will be presented. This set-up comprises one 2.5kWth H2 SESMR-reactor (about 0.85 Nm3/h H2) operating batchwise with dolomite as the CO2-sorbent. The reactor developed is designed like a parallel plate heat exchanger where the mixture of sorbent and reforming catalyst is packed between the heat exchanging plates. The demonstration set-up includes a 1kW SOFC operating in a continuous mode. The set¬up will therefore demonstrate continuous simultaneous hydrogen- and electricity production, but cannot demonstrate simultanuous electricity- and CO2-production. The set?up is well equipped for on-line monitoring of gas composition, flows and temperatures. This important part of the demonstration set-up is developed and provided by Christian Michelsen Research (CMR). A minor part of the project is the development of a continuous circulating fluidized bed SESMR-reactor system and in another related project the focus is on the development of more suitable sorbents. In these two projects co-operation with University of British Columbia and Lousianna State University, respectively, is highly appreciated.

Jan 1, 2005

By G. T. Lineberry, R. S. Mateer

Often only after years of "technical dormancy" do errors in published literature become apparent and meaningful. To prevent duplication of effort for future generations, the following corrections are offered. These errors were discovered during a recent study in which a computer program for mine hoist rope selection was developed (Lineberry and Mateer, 1988). In order of increasing gravity: Captions for Figs. 3 and 4 are transposed. Purported to be a more accurate method of rope selection than the process of successive approximation, the direct method assumes linearity between a given rope's minimum breaking strength, T, and unit rope weight, WV. Because of the sensitive location of the constant, K, in equation (8) for breaking strength, the significance of this nonlinearity is magnified. For a typical 6 x 37 class fiber core wire rope (Wire Rope Corp. of America, 1985), K actually varies from 43,650 to 52,190, depending upon rope diameter. Although the direct solution permits a rapid selection of hoist rope, an indirect (iterative) solution procedure is favored because of its improved accuracy and ease of computerization. Equation (8) for minimum breaking strength is in error. It should read:

Jan 1, 1990

By Shawn Collins

BACKGROUND The history of the Pine Point Mine is a rich one. This property once boasted one of the largest and most profitable lead-zinc mines in Canada's long and storied mining history. The Pine Point mine used open pit technology to extract the ore, but they faced several challenges. In addition to logistics problems with haul distances and metal prices, the mine faced the challenge of a large in flow of water from the Great Slave Lake. Eventually, the Pine Point Mine was closed leaving behind a large deposit of lead-zinc ore. Following the closing of the Pint Point Mine, Tamerlane Ventures Inc. acquired this property which includes approximately 70 million tonnes of lead-zinc reserves. The initial phase of this project will concentrate on the R-190 deposit as a test site to prove their new approach for extracting the ore. The R-190 reserve is believed to have approximately 1,014,000 million tonnes of high grade ore varying from 5% to 52% combined lead-zinc. Once the pilot project proves the approach is valid, the process will be repeated in approximately 33 other ore bodies on the property. This paper is written to discuss the design process to determine the most effective means of placing production and service equipment in the same shaft. Currently the design work and the mining scheme is complete, but lead-zinc pricing has prevented Tamerlane Ventures Inc. from moving forward with the project.

By G. T. Lineberry, R. S. Mateer

Often only after years of "technical dormancy" do errors in published literature become apparent and meaningful. To prevent duplication of effort for future generations, the fol¬lowing corrections are offered. These errors were discovered during a recent study in which a computer program for mine hoist rope selection was developed (Lineberry and Mateer, 1988). In order of increasing gravity: Captions for Figs. 3 and 4 are transposed. • Purported to be a more accurate method of rope selection than the process of successive approximation, the direct method assumes linearity between a given rope's minimum breaking strength, T, and unit rope weight, Wv. Because of the sensitive location of the constant, K, in equation (8) for breaking strength, the significance of this nonlinearity is magnified. For a typical 6 x 37 class fiber core wire rope (Wire Rope Corp. of America, 1985), K actually varies from 43,650 to 52,190, depending upon rope diameter. Although the direct solution permits a rapid selection of hoist rope, an indirect (iterative) solution procedure is favored because of its im¬proved accuracy and ease of computerization. • Equation (8) for minimum breaking strength is in error. It should read:

Jan 1, 1989

By Charles D. Haynes

Outside air for ventilating coal mines in Alabama varies considerably in both temperature and moisture content during the year. Alternate condensation and evaporation of the moisture on mine roofs may result in stresses detrimental to the strength of mine roof. It is well known that the clays in shales absorb moisture, and many investigations have noted the weakening of shales by absorption of moisture. Parker (1970) concluded that there is an annual cycle of rock deterioration in mine roof rock caused by the annual temperature-humidity cycle at the surface. He further noted that moisture reduces the strength of dry rock by one-half, that moisture added to dry rock can cause failure in compression, and that drying of wet rock causes tensile stress buildups by shrinkage. His recommendations for alleviating the moisture-temperature problem was to seal the rock in critical areas and to control ventilation so that air temperature will be lower than rock temperature. The latter recommendation will avoid condensation on the rock surfaces. Hartmann and Greenwald (1941) published the results of a very comprehensive experimental project to determine the effect of temperature and humidity changes on the behavior of mine roof. Their general conclusions included statements that roof rocks were very sensitive to moisture changes, but had low coefficients of thermal expansion. The coefficients were twice in the direction normal to the bedding plane as compared to the parallel

Jan 1, 1975

By Peter Soo

Pvestrained Ferrovac E iron has been neutron-irradiated at approximately 90°C to an integrated flux of 1020 nut (E > 0.82 mev]. The irradiation was found to produce an incveased temperature dependence of the flow stress in addition to a greatly increased athemal stress. Measurements of the flow stress and stress relaxation, from which the activation volume and activation energy for slip were deduced, show that neutron irradiation changes the rate -controlling slip process to one based on dislocation interactions with tetragonal distortions which are Produced around submicroscopic interstitial loops in the lattice. The study indicates that without prestraining prior to irradiation the chances of detecting a change in the rate -controlling slip process are greatly reduced because in the initial stages of slip a substantial fraction of the radiation defects are swept out of the slip plane by gliding dislocations. Thus, activation parameters which are subsequently measured are representative of a greatly reduced defect density and would not differ appreciably from those for unirradi-ated material. The large increase in the athermal component of the flow stress is probably connected with the presence of depleted zones in the lattice which are introduced by irradiation. ALTHOUGH fast neutron-irradiation has not been observed to markedly alter the activation parameters for slip in bcc metals,' small but significant changes do occur. Most experimenters agree that irradiation predominantly increases the athermal component of the yield stress.'-= In addition to this, Laidler and smidt7 have shown that in iron irradiated to 5 X 10" nvt and molybdenum irradiated to 10" nvt, changes occur in the activation volumes for slip. A similar conclusion has been reached by Milasin and Malkin8 for irradiated iron. Work by Ohr et a1.5 shows that for Ferrovac E iron, irradiated to 1.2 X 1016 nvt, small increases in the activation energy for slip also occur. So far these changes in the activation parameters have not been explained on a firm theoretical basis. One important factor which would minimize the chances of detecting a change in the slip mechanism upon irradiation is the presence of "channeling" which has been observed in molybdenum,9 niobium,10 and iron.11These channels are formed by gliding dislocations which sweep irradiation defects out of the active slip planes and thereby create zones in which continued dislocation motion is encouraged. The activation parameters for the dislocations gliding in the defect-free channels would, therefore, be similar to those for unirradiated iron and a change in the rate-controlling slip process would be difficult to detect. In the present work, an attempt has been made to reduce the effect of uneven deformation on the measured activation parameters for slip in neutron-irradiated Ferrovac E iron polycrystals, so that a more realistic assessment of the effects of neutron-irradiation could be made. Primarily, the experiments involve the irradiation of specimens which had been prestrained to 9 pct elongation at room temperature prior to insertion into the reactor. It was hoped that the introduction of a large number of evenly distributed dislocations would substantially decrease any channeling effect which might otherwise occur. MATERIAL AND EXPERIMENTAL PROCEDURE The starting material was vacuum-melted Ferrovac E iron, an analysis of which is given in Table I. The standard tensile specimen had a gage length of 1.125 in., a cross-sectional diameter of 0.120 in., and a re-crystallized grain size of 1.2 x 10-3 in. All tensile tests were conducted on a floor model "Instron" tensile machine at a strain rate of 3 x 10-4 per sec. The irradiation of the prestrained specimens was performed in the Brookhaven High Flux Beam Reactor to an integrated flux of 1020 nvt (E > 0.82 mev) at a temperature of about 90°C. All specimens were excap-sulated in high-purity aluminum sheaths which were lightly swaged around the samples to ensure good thermal contact. Subsequent measurements on the irradiated specimens showed that within experimental accuracy the swaging had not deformed them. EXPERIMENTAL RESULTS Fig. 1 shows the flow stresses for a series of unirradiated control samples. In order to produce a comparable dislocation substructure throughout the test sm range, all specimens were prestrained

Jan 1, 1970

By Y. V. Swamy, B. Bhoi, H. S. Ray

Low-grade manganese ores with low Mn/Fe ratios can he enriched through selective carbon reduction of iron oxide to magnetite followed by magnetic separation o f the magnetite. Thermogravimetric analysis (TGA) was used to assess the preferential isothermal reduction of pure M1702 and Fe2O3 using solid carbon. This was followed by reduction of a synthetic analogue of composition comparable to an actual low-grade ore (i.e., Sandur manganese ore, Sandur, India). The carbothermic reduction of the manganese ore converts the hematite and goethite minerals to magnetite (Fe3O4), with the magnetite then going into the magnetic, fraction. The resultant nonmagnetic ,fraction becomes depleted of iron with an enhanced manganese content. These results show that it is possible to reduce the iron from 22% to 5.85%, thus increasing the Mn/Fe ratio from 1.52 to 6.2 with a manganese recovery of about 50%. The recovery was, further improved by grinding the magnetic fraction to -75 µm.

Jan 1, 1999

By G. R. Forbes

Flotation froth machine vision systems provide consistent real-time measurements pertaining to the state of the flotation cell being monitored. Typical measurements include froth velocity, froth colour, froth texture and froth stability. This paper presents the results from test work conducted on the molybdenite rougher circuit at the Kennecott Utah Copper Concentrator during February 2006. Machine vision results show that it is not possible to accurately determine bubble size distribution information for the molybdenite froth, despite using state-of-the-art methods. Instead, it is necessary to make use of texture measurements to classify the various different froth states. Numerous combinations of texture measurements and classifiers are used to determine the best combination. Results show that the Fourier ring based texture measurements perform the best when both K nearest neighbour and Gaussian mixture model classifiers are used. The concentrate grade of the flotation cell is modelled using combinations of froth velocity and froth texture descriptors. The results show that by using a linear combination of these descriptors rather than either one by itself it is possible to account for a much larger percentage of the variation observed in the concentrate grade data. Adjusted R2 values of 92% and 84% are achieved when modelling the copper and the molybdenite concentrate grade respectively.

Jan 1, 2014

By A. D. Schwope, L. R. Jackson, A. M. Hall

In the course of an extensive investigation of the comparative properties of several types of copper, data were obtained on the cold working and subsequent recovery and recrystallization of the copper. In this paper, relations between the degree of cold work and the course of re-crystallization are developed. In particular, it is shown that the course of recrystallization over long periods of time and at low temperatures can be predicted with reasonable accuracy from short-time high-temperature recrystallization data. Materials Used in The Investigation Three types of copper were used in this investigation; these were tough pitch, OFHC, and OFHC copper with 15 oz per ton of silver added identified herein as Lots C, D, and F, respectively. The material was supplied by the American Metal Co. Ltd., and processed by the Rome Cable Co. The analyses of the three types of copper are given in Table I. Originally, it started as wire bars 4 X 4 X 54 in. These bars were heated to 871° C in air and hot rolled to % in. rod. This rod was cold drawn to 0.204 in. rod (70 pct reduction) in three passes and annealed at 427°C for 4 hr. A portion of the 3/8 in. rod was saved for more detailed cold-drawing experiments. Starting with the annealed 0.204 in. rod, hard-drawn wires were produced by cold drawing to 0.081 in. wire in 7 passes (84.4 pct reduction in area). Half-hard wires were made by cold drawing the 0.204 in. rod to 0.102 in. wire, (75 pet reduction) in 6 passes and annealing at 427'C for 4 hr. This annealed wire was then drawn to 0.081 in. wire, (37.1 pet reduction) in 2 passes. Square rod was made by hot rolling wire bars to Re in. rod in 8 passes. This rod was then cold drawn to 0.445 in.-diam rod and annealed for 346 hr at 538°C. It was then cold drawn to 0.325 in. rod and again annealed at 538°Cf or 3 1/2 hr Hard square rods were then made by cold rolling this material to 0.257 X 0.257 in. rod, a reduction in area of 20.5 pct. Half-hard square rods were made by cold rolling to 0.268 x 0.268 in. square, annealing for 3 1/4 hr at 538°C and cold rolling to 0.257 x 0.257 in., a reduction of 8.5 pct. Soft wire or rod was made from all types of copper by annealing the hard-drawn material at 343°C for 3 hr in steam. The grain size of the annealed 0.081 in. wire varied slightly among the three lots: from o.o15+.oz5 mm in the silver-bearing OFHC to 0.035-0.045 mm in the OFHC copper. The annealed 0.257 in. wires were more uniform in grain size, averaging about 0.035-0.045 mm. Representative structures are shown in Fig I. Effect of Cold Drawing and Tensile Strain on Strength of Copper Conventional tensile tests were performed on the three types of copper in the various degrees of hardness described above. Results of these tests are tabulated in Table 2. The results in Table 2 are 6

Jan 1, 1949

By N. Sinclair

"In open pit dozer bulk push operations, the material left resting against the highwall after blasting poses an issue. This is because dozers cannot physically get in behind the waste to begin the bulk pushing process. Instead, an excavator can be used to side-cast this waste for the dozers to access. An alternative technique is to have the dozers ‘side-cut’ the material, which involves the dozers running parallel to the wall, digging out the material, and eventually rotating their blades to begin bulk pushing. Industry practices suggest the latter technique is less productive and economical than using an excavator. However, such excavator sidecasting ‘economic viability’ assumes that smaller/ancillary type excavators are used (i.e. less than 23 m3 bucket capacity). So, what happens if some mine sites are restricted to using relatively larger excavators (> 23 m3 bucket) that are preferred for higher priority digging tasks? When can they avoid using their excavator? This paper explores multiple scenarios that have been designed and developed to simulate data results, which identify conditions in which the dozer side-cutting technique becomes more economically viable than excavator side-casting in terms of decreased unit cost per loose cubic metre. IntroductionOptimizing the cost of waste removal operations is important for the profitability of opencast coal mines. In the past decade, dozer bulk pushing has emerged and taken over from traditional waste removal operations such as dragline and truck-and-shovel methods at various sites around the world (Beatty, 1994). In a typical bulk push operation, once the bench has been blasted, waste is left resting against the highwall, which can either be cleared using a loading unit or by having the dozers ‘side-cut’ the highwall.Dozers perform most effectively when slot dozing side-by-side, perpendicular to the highwall. However, when dozers are required to remove material off the highwall, they must push parallel to the highwall, rather than perpendicular, hence ‘side-cutting’ the material to ensure a clean face. While dozer sidecutting is possible, it has been found that the majority of mine sites use a loading unit in this situation to avoid dozer inefficiency. Other perceived issues with dozer side-cutting include higher maintenance requirements and safety risks to dozer operators working in close proximity to the highwall."

Jan 1, 2019

[Title 1 Contents Page . 3 Officers and Directors 5 Past and Present Officers 6 Standing Committees 9 Professional Divisions 11 Technical Committees 12 Institute Representatives on Boards 17 United Engineering Society 17 Engineering Societies Library Board 17 Engineering Foundation Board 17 Other Committees 17]

Jan 1, 1928

[RALPH ADAIR Ore Dressing Consultant Bull Mtn. d., Asheville, N. C. Phone 4-1693 JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington, D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. I. R. BERENT Engineering Consultants and Contractors Mineral Exploration, Mine Evaluation, Mine Designs and Mine Management 156, Ataturk Bulvarl-Ankara, Turkey BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 8 Howard-Canfield Bldg. Santa Barbers, Calif. COWIN & CO. Mining Engineers and Contractors Consulting Shaft & Slope Sinking Appraisal Mine Development Reports Mine Plant Construction I. 18th St. S. W. Wham, Ale., Phone 56-5566]

Jan 1, 1952

By R. V. Smith

The theory for unsteady radial flow of gas, as simplified by Aronofsky and Jenkins, has been reviewed and compared with actual well performance. This study indicated that the theory should be modified by the introduction of an empirical "rate of flow" function "Y(q)". The expansion of the theory on the flow of gas to include a Y(q) term bridges the gap between the theory of unsteady-state flow of gas and actual gas-well behavior. Apparently, the Y(q) term is a function only of the rate of flow for a given well. The completion factor or skin effect is associated with the Y(q) function in such a manner that at least two or more sets of drawdown or pressure build-up tests are needed to separate the Y(q) function and the completion factor. Since the Y(q) function used in this report represents an energy loss dependent on rate of flow near the well-bore of a gas well which is in addition to the loss required by Darcy's law, the Y(q) function is related to the exponent of the back-pressure curve for a gas well. Techniques and equations are presented which permit the estimation of stabilized and "short-time" deliver-abilities. INTRODUCTION The published theory of radial unsteady-state flow of gas through porous media may be divided into papers1-" which use Darcy's law as a premise and other papers4-7,16-10 which recognize that Darcy's law may not hold for flow into gas wells. Miller8 compared theory based on Darcy's law with actual gas-well behavior and concluded that flow into gas wells deviates from Darcy's law. Houpeurt4,5 in a thorough investigation of flow into gas wells concluded that the flow rate into a gas well is proportional to the difference between the squares of upstream and downstream pressures elevated to a power between 1.0 and 0.5. Houpeurt also concluded that the deviation from Darcy's law is caused by irreversible, kinetic energy exchange between the flowing gas and the porous media. Tek9 presented a complete evaluation of the flow problem in gas wells. Several investigators state that the inclusion of gas compressibility into flow equations based on Darcy's law does not begin to explain the flow problems suggested by gas-well behavior. For many years, natural-gas engineers have realized that gas wells by actual test exhibit behavior which cannot be explained entirely by Darcy's law. Many tests on gas wells have indicated that a value of 0.85 for the exponent in the back-pressure equation is a fair average for many wells. However, Darcy's law either for steady or unsteady-state conditions indicates that the exponent should be 1.0. The purpose of this paper has been to examine this deviation from Darcy's law and to present a reasonable mathematical means of evaluating the deviation. The method presented in this paper combines previous theory with an empirical function to provide a description of gas-well behavior. All equations in this report are for constant terminal-rate-of-flow conditions. While present methods of testing wells usually are not based on this concept, they are believed to approach the constant terminal-rate conditions closely in many tests. However, several gas wells were tested by holding the rates of flow constant in order to approach more closely the constant terminal rate of flow; the results confirm the concepts presented in this paper. REVIEW OF THEORY FOR UNSTEADY-STATE FLOW OF GAS The basic partial differential equation for the flow of natural gas has been given in technical literature; the equation for a cylindrical reservoir with the well in the center is