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By H. P. Schwede, H. G. Doll

This paper describes a method to provide identification of particular depths in a borehole through the use of radioactive markers. The correlation of a marker, placed in the wall of a borehole, with known points of the electrical log and with the casing collars in the cased hole permits accurate positioning of tools with respect to a formation, regardless of absolute depth. Such a process is particularly useful in gun perforation of a casing in a well. Technique and equipment are discussed and illustrated. Examples are given of practical application in the field. Introduction During the past decade the search for petroleum has increased the importance of testing zones at depths in wells which have become progressively deeper. The development of new techniques, such as electrical logging, has permitted the identification of producing formations which consist of comparatively thin strata. When thin beds are to be produced at great depths, the problem of positioning tools accurately to place the well in production becomes acute.l Continuous consideration is being given in the petroleum industry towards the improvement of depth measurements in a borehole. The accuracy in absolute depth measurements, whether made in an open or cased hole, whether determined by a cable or a drill pipe, depends upon a number of factors, such as tension, temperature, and calibration. For example, the effects of tension from the weight of 10,000 ft of drill pipe and the thermal expansion of this length . of pipe, where its average temperature has increased SO"', will Produce an elongation as much as 8 ft.2 The effects Of such factors can be minimized through the use of care in depth measurements, the application of corrections based on experience, and continuous calibration or checking. The fact that different methods and different tools are used to determine the depths of formations in wells will sometimes give rise to a difference between measurements. It is evident that an important requirement in a well is the ability to locate at will any subsurface point. While absolute depth measurements have ion in recent years, it is reassuring to have other means to verify, for example, that a casing is perforated at a particular place with reference to a zone within a formation. Such a check on measurements may be had by placing a reference marker at a point known with respect to the electrical log of the borehole. That point is usually chosen to be in proximity to the 'One to be perforated. Thus, only short in depth measurements are made and any inaccuracy becomes very small and of minor importance' The use of reference markers located at fixed points predetermined in each zone where future operations are contemplated enables the operator to position any tool

Jan 1, 1948

By Ron Bradburn, Derek Perkins

"The Brenda mine is located in south central British Columbia, 22 km north west of Peachland, in the heart of the Okanagan Valley. Situated at an elevation of 1500 metres, the mine area straddles the divide between the headwaters of Trepanier Creek and Peachland Creek. These flow into Okanagan Lake, the chief valley water resource located 1100 metres below. The creeks are of great significance to the water management of the area as they constitute the water supply for the Municipality of Peachland, a thriving retirement community with a population of 5000. A location map is shown in Figure 1.The history of the Brenda Mine operation has been well documented previously. After twenty years of operation, the open pit mine shut down in June 1990 due to the depletion of its ore reserves. During the course of its life, it produced 109 million tonnes of waste rock which is thought to contain approximately 0.10% copper as chalcopyrite and 0.015% molybdenum as molybdenite stored in four rock piles around the pit. Similarly, approximately 200 million tonnes of tailings were produced grading 0.015% copper and 0.005% molybdenum. During operation, tailings were hydrocycloned to produce a coarse sand for dam building with the fine slime stored behind the dam. It is estimated that 40% of the tailings were used for the dam construction. The layout of the mine site is shown in Figure 2.The mine was operated under a zero discharge permit. This was achieved by diverting practically all surface water flowing towards the mine area around the site. Water affected by mine operations, was discharged to the tailings impoundment, and recycled to the mill for reuse. The recycle rate was 90% and seepage from the tailings embankment and saddle dam was pumped back to the tailings pond. Because acid drainage was not a problem with the low grade Brenda rock, runoff from the rockpiles was initially released to the local environment. However, due to the alkaline nature of the waste rock, dissolution of low concentrations of molybdenum in the site runoff waters became evident by the late 1970's. The molybdenum content of Peachland Lake, the water reservoir for the municipality of Peachland, approached the Canadian Drinking Water Standard of 0.25 ppm. By 1979, a series of diversion and collection ditches was completed to direct all runoff water from the rockpiles to the tailings impoundment area. This had a significant detrimental effect on the site water balance causing it to go into a considerable surplus condition. During normal operation, this oversupply was contained by the rate of tailings dam building. An economic shutdown of the mine during 1984 forced a limited discharge from the site to protect the integrity of the tailings dam."

Jan 1, 1995

By E. D. Gardner

Introduction Oil shale deposits have been exploited in various countries throughout the world, but generally with government aid. The oil-shale industry of Scotland perhaps is the oldest and best-known; the largest was conducted in Manchuria by the Japanese during World war 11 as a source of liquid fuels for military uses. In general, foreign oil-shale deposits that have been exploited are much lower grade than those in the western United States. Considerable interest began to be shown in western oil shales in 1916; the peak of activities was in 1923. The catlin operation, near Elko, Nevada, perhaps was the nearest approach in this country to an oil-shale enterprise on a commercial scale. Over 100 companies were formed, ostensibly for exploiting the oil shale; a large number of them, however, proved to be stock promotions only, which gave the embryo industry a black eye. The Bureau of Mines operated an experi-mental oil-shale retort plant near Rifle, Colorado, from September 1926 to June 1927 and again from April 1928 to July 1929, after which the plant was dismantled. By this time the East Texas oil fields had come ill and the country lost interest in substitute liquid fuels. During World War II the Nation again became concerned about the magnitude of its petroleum reserves. Congress (April 1944) directed the Bureau of Mines to build and operate demonstration plants to produce synthetic liquid fuels from coal, oil shales, and agricultural and other products; a five-year Program was authorized. *' a part of this program the Bureau of Mines has built, at Anvil Points near Rifle, Colorado, a retort plant and develOped an experimental mine to supply the plant with oil shale. An important part of the mining work at Rifle is to devise methods and select practices for mining the oil shale on a commercial scale at the lowest practicable cost. The product to be mined has a relatively low value, a fact that must be kept in in mind. The combined aim of those in charge of the mining and those in charge of retorting is to demonstrate that the shale oil can be produced at a cost per barrel corresponding to the current quotation for crude petroleum —or at least very close to it. Plans call for an uninterrupted flow of broken oil shale from the lace in the mine, through crushers, through the retorts and thence to the disposal dump. The disposal of the spent shale in the Ride area should present no unusual problem. Mining research has consisted so far of Paper studies of the general phases of the probleml determination of the widest Span that the roof Stone will stand safely unsupported, and drilling problems. underground development has not proceeded far

Jan 1, 1949

By Graham Bright

Up until a few years ago most of the electrical equipment used in the mines of this country was developed for industrial purposes and was adapted for use in mines by slight modifications. It became apparent, however, that mining conditions differed widely from most industrial applications and it became necessary to design and develop apparatus, particularly suited for use under mining conditions. Most of the electrical apparatus used in mines today, however, does not owe its success entirely to mining development, but in many cases developments in other branches have been taken and improved upon and modified to meet mining conditions. Power Plant: In the earlier days the power plant for the production of electric power usually consisted of fairly small belt driven direct current generators operated from reciprocating non-condensing steam engines. Today where possible the mines purchase power from central stations and where not possible it is ususally produced from turbine driven plants using non-condensing turbines for the smaller plants and condensing turbines for the larger plants. The bad water conditions at many of the coal mines in this country is, responsible in a large measure for the high cost of upkeep and repairs in isolated power plants. This feature with the type of labor available makes it difficult to operate an isolated plant condensing except in the larger mines where water conditions are good and the apparatus can be taken care of. The geared turbine is a particularly simple and rugged piece of apparatus and requires very little attention over long periods of time. Hoists: The first electric hoists to be installed used various types of motors designed for railway or industrial purposes, and the control furnished was far from satisfactory. Today most of the mine hoist motors are of the alternating current type, especially designed for hoisting service. The control for motors of 200 H. P. or over is usually of the magnetic of liquid rheostat type, and as built today will operate over fairly long periods with a very moderate cost of up-keep. Hoists of 1000 H. P. or larger are usually of the direct current type using field control and receiving power from a flywheel or synchronous M. G. set. Hoists of this type have made remarkable records in regard to continuity of operation and low cost of up-keep. Where high speed operation is desired in either coal or metal mines, the D. C. equipment using field control and a separate M. G. set to supply power to the hoist motor is not only the safest and most economical but in many cases is the only type of equipment capable of satisfactorily obtaining the output required. A number of improvements have been brought out with the field control scheme in connection with the acceleration, retardation, overfeed and overwind of the hoist. With these new developments the hoist operator can no longer abuse the hoist by improper manipulation of the control handle. Until a few years ago the matter of safety devices was not given much consideration when installing hoisting equipment. At the present time the safety devices are considered one of the most important items in connection

Jan 1, 1922

By Brooks J. Klimley, Daniel M. Higgins, Grover R. Castle

Measuring The Economic Viability Of Resource Projects (A Western Surface Coal Project) The bankers approach to the analysis of a new "green fields" mining project is similar but different from the approach that the pining company might take. The purpose of this paper shall be to discuss the techniques that are used by mining companies and bankers as they try to measure the economic viability of mining projects. The analysis of these new projects (by both the mining companies and the banker) is based on a projected revenue stream and not on historical earnings or past perfomance because these projects are start up situations with no history to look to. The starting point in the analysis of these projections is the choice of the assumptions to be used in preparing these projections. After the assumptions have been determined and the projections are prepared then the projections are submitted to various tests in order to determine whether the project measures up to previously agreed upon minimum standards. In order to illustrate the analytical procedures used in evaluating a mineral project the writer has constructed a hypothetical case involving the development of a western surface coal mine (Property). The basic data in connection with this hypothetical new project is described in the next section of this paper. After the Description of the Project is a section which shows the type of analysis that a mining company might prepare in order to approach a bank for a loan and the final section illustrates the type of analysis that a bank might prepare in evaluating this loan request. Description Of The Project or Basic Data In Connection With Undeveloped Western Surface Coal Property An independent mining/geological Consultant's report has been completed on the Property which confirms that the Property contains 175 million tons of economically recoverable coal subdivided into the following reserve categories in accordance with U.S. Bureau of Mines and U.S. Geological Survey definitions: Measured or Proven 90,000,000 Indicated or Probable 50,000,000 Inferred or Possible 35,000,000 The owners of the reserves have chosen to drill up those reserves that are nearest to the subcrop and have not spent as much time on those portions of the Property which are on the fringes of the deposit where the overburden is thicker because the stripping ratio and hence the operating costs and capital requirements are higher down dip. The proven reserves are based on an average thickness of 80 feet, of which a mining recovery of 90% is projected. The overburden thickness varies from 0' to 280' with an average thickness of 127'. The overburden consists mainly of scoria, sandstone, gravel, shale and silty clay. 134 holes were cored (and analysis done on five foot increments) in the measured reserve on the following spacing: 100 foot centers to define the burn line; 1,320 foot centers to define the early mining areas; 2,640 foot centers to identify the later mining areas.

Jan 1, 1985

By W. K. Hardy, H. H. Stadelmaier, L. J. Huetter

The ternary system Co-Sn-C was studied in the cobalt-rich region. The liquidus projection ulas established and two fonr -phase reactions were found. An isothermal section at 950°C was worked out. In the region studied the following phases were observed: cobalt-rich solid solution, graphite, binary compound y -cobalt-tin, and a ternary compound. As a result of the limited solubility of carbon in liquid cobalt-tin alloys, the investigation was limited to the cobalt-rich region. Tin contents up to 32 at. pct were studied. Cobalt of 99.99 pct purity, tin of 99.97 pct purity and synthetic graphite of 99.93 pct minimum purity prepare the alloys. Carbon determinations of all alloys were obtained by gas volumetric analysis. Samples were investigated microscopically and by X-ray diffraction using CoK, and FeK, radiation. Cooling curves were obtained with a number of alloys to determine the temperature of the four-phase reactions. The thermocouple was calibrated with the melting points of high-purity silver and copper. In the region studied the following phases were observed: Cobalt-rich solid solution (face-centered cubic) Graphite. Binary compound y (solidifies congruently at composition Cop~n)'. Ternary compound k which is face-centered cubic with superlattice and nonferromagnetic.' In Fig. 1 the fields representing the projections of the liquidus surfaces were determined by microscopic investigation and are labled by their primary phase. In the field labled C graphite is the primary phase. During solidification in this field much of the primary graphite was expelled through the surface of the melt. It could not always be established microscopically whether the remaining graphite was primary or purely eutectic. Therefore it was not possible to determine accurately the boundary curve which drops from the binary eutectic el at 1309 "~~ to the point of the four-phase reaction at F. The ter-nary carbide is the primary phase in the field labled k. To the right of this field the primary graphite is consistently nodular whereas flake graphite is observed at tin contents somewhat below F. The ternary carbide does not appear to solidify congruently. The graphite is attacked in a peritectic reaction along the boundary between k and C. Thus no graphite is observed in alloys in the k field. In alloys right of the boundary between k and C the graphite nodules are located in the center of the k crystallites, further documenting the peritectic nature of the reaction with the graphite. A four-phase reaction was found at F and 1120 &3"C. The most likely reaction is L+ CY-Co + C — k. Below the temperature of the binary eutectic ez at 1112" a second four-phase reaction was observed at E and 1100 lt3"C. It is the ternary eutectic L — CY-Co + k + y. Figs. 2(a ) to (e) show microstructures of the ternary alloys in the as-cast condition. Fig. 2(a) shows the eutectic a-Co + C (with some primary graphite) with the carbide k in the grain boundaries. Fig. 2(b) shows primary cobalt (dark areas) and the eutectic a-Co + k which is formed along F-E.

Jan 1, 1961

By F. King, R. Sutherby, J. Been

With thousands of kilometers of buried oil and gas pipelines throughout the country, carrying flammable, high-energy hydrocarbons, the integrity and safety of this transportation and distribution network are paramount. The pipeline industry has the primary responsibility for pipeline safety and has in many ways taken the lead in dealing with safety issues. Over recent years, regulatory demands have increased, requiring operators to comprehensively evaluate their pipelines through indirect and direct inspections and to manage risk through integrity programs. Mechanistic and correlative models have been developed that assist in the prediction of pipeline integrity and the determination of reassessment intervals. These lifetime prediction models are based on decades of laboratory research as well as pipeline operating data, material data, and field monitoring data pertaining to soil conditions and CP. An overview is presented of an integrated approach towards the development of such models for the evaluation of external cracking and corrosion of transmission lines.

Jan 1, 2005

By Zamel GI

The utilisation of fossil fuels, including coal (of which Australia is a large producer and exporter) is a significant contributor to the emission of greenhouse gases. Methane gas, formed during the coalification process, is present in coal seams to varying levels depending on the rank and depth of the deposit. This gas usually escapes to the atmosphere during mining operations without prior conversion to C02 or utilisation as fuel. The quantity of methane released can represent from less than one percent to more than five percent of the carbon content of the coal mined. Per unit of carbon, methane has a greenhouse impact many times that of C02. The emission of uncombusted methane to the atmosphere can therefore represent a greenhouse impact of similar porportions to that of the CO2 formed by combusting the mined coal. However, greenhouse emissions from coal can be minimised by collecting the coal seam methane and converting it to water vapour and the less damaging form, CO2. If such conversion is carried out while performing useful work, the methane can further reduce greenhouse emissions by displacing other fossil fuels. Technology has been developed to allow coal seam methane gas to be economically collected in a pure form, uncontaminated with air. This pure methane can be used to supplement natural gas supplies, to generate power or for the production of chemicals or substitute transport fuels. By collecting and utilising coal seam methane, the greenhouse impact from the mining and use of coal can be minimised, with significant reductions possible in the case of gassy deposits.

Jan 1, 1989

By Ralph M. Hunter

Until recent years, maintenance of surface coal handling facilities was a relatively simple task. Equipment consisted principally of conveyors, screens and crushers of comparatively simple construction. Electrical equipment consisted of motors and starters, with little, if any, interlocking. In most cases failure of any component affected only the grades of coal loaded so that even a prolonged breakdown did not affect mine operation materially. However, with the introduction of modern cleaning plants, the picture has changed. The equipment is much more complex and therefore more difficult to maintain. In many cases failure of any component of the plant prevents loading of coal. Even if provision is made to bypass, the quality of coal loaded is lowered, affecting markets. In the case of plants designed to permit full seam mining, marketable coal cannot be loaded without operation of the cleaning plant. Under these conditions it is apparent that considerable thought and effort toward better maintenance are justified. In order to assure continuous, efficient and economical operation, maintenance should receive consideration, not only after the plant is in operation, but while it is being designed. It is hardly necessary to say that the designer should strive for sturdi-ness and wearing qualities. It is sometimes not realized, however, that even the best parts will sooner or later require replacement or repair. The designer should, there- fore, give consideration to accessibility. Anyone who has had to do with cleaning plant maintenance is familiar with installations where several hours are required to get at a part that can be repaired or replaced in a few minutes, once it is accessible. As in most cases, experience is the best guide. The men who operate and maintain this equipment know the problems encountered. Whenever available, the opinions of these men should be sought and heeded. As an example, we might consider the refuse elevator on a Chance Cone. Our company is now operating three of these cones, the first of which was installed in 1941, and the latest in 1946. Exact records are not available, but well over 50 pct of delays charged to the Chance Cones have been caused by the refuse elevator. This elevator receives refuse from the cone and carries it to a point above the water level of the cone, discharging onto a dewatering and desanding screen. Since the elevator operates under water and necessarily has close clearances in the lower boot, it tends to jam on large pieces of refuse or tramp iron. The chain, buckets and boot are also subjected to the action of water, sand and refuse, which accelerate normal wear. In case of jamming or chain-breakage it is necessary to drain the elevator and the cone so that even a minor fault in the elevator causes a considerable loss of time for the cone. In our new plant, which will contain two Chance Cones, the refuse elevator has been eliminated. This was accomplished by raising the cone so that the refuse gates could discharge directly onto the dewater-

Jan 1, 1949

CAT offers three different methods to accomplish crowd & retract on an electric rope shovel Rack and pinion Rope crowd HydraCrowd The presentation will compare the three systems and introduce the benefits of the Hydracrowd

May 1, 2013

By C. M. Young

The following paper has been prepared with the object of placing on record in the Transactions some facts concerning the present condition and future prospects of the coal industry of Illinois. In presenting it, the writer wishes to say that a considerable amount of the material contained is taken from the publications and records of the Illinois Coal Mining Investigations, the annual Coal Report of the State Mining Board, and the work of the State Geological Survey. Coal Beds and Mining Methods According to the latest maps of the State Geological Survey, there are only 19 of the 102 counties of the State some portion of whose territory is not within the borders of the coal measures. If outlying areas in Calhoun and Whiteside Counties are considered, the number is reduced to 17. This does not mean that all of the 85 counties that are partly or wholly underlain by coal measures will become producers, as there are some portions of the State in which the coal does not occur in beds of such thickness as to warrant the hope that it can be mined. The mining of coal is widespread, however, for in 1916 there was production from 61 of the 102 counties of the State, There seem to be no cases in which operations will be limited by depth, as none of the coal measures lie at depths much greater than those at which it has been proved that coal may be profitably mined in this field. In fact, the deepest shaft reaching a bed of bituminous coal in the United States is located in this State at Assumption, where coal only 3 ½ ft. (1.07 m.) thick is worked at a depth of 1004 ft. (306 m.). The coal beds occur in the form of a basin which is deepest along a line extending through the central part of the State and bearing a little west of north. The northern, western and southern borders of this basin lie within the boundaries of the State, but on the eastern side the Illinois field is continuous with the Indiana field. The glacial drift covers all except the extreme southern end of the State and the visible outcropping

Jan 1, 1918

By H. G. Doll, H. P. Schwede

This paper describes a method to provide identification of particular depths in a borehole through the use of radioactive markers. The correlation of a marker, placed in the wall of a borehole, with known points of the electrical log and with the casing collars in the cased hole permits accurate positioning of tools with respect to a formation, regardless of absolute depth. Such a process is particularly useful in gun perforation of a casing in a well. Technique and equipment are discussed and illustrated. Examples are given of practical application in the field. Introduction During the past decade the search for petroleum has increased the importance of testing zones at depths in wells which have become progressively deeper. The development of new techniques, such as electrical logging, has permitted the identification of producing formations which consist of comparatively thin strata. When thin beds are to be produced at great depths, the problem of positioning tools accurately to place the well in production becomes acute.l Continuous consideration is being given in the petroleum industry towards the improvement of depth measurements in a borehole. The accuracy in absolute depth measurements, whether made in an open or cased hole, whether determined by a cable or a drill pipe, depends upon a number of factors, such as tension, temperature, and calibration. For example, the effects of tension from the weight of 10,000 ft of drill pipe and the thermal expansion of this length . of pipe, where its average temperature has increased SO"', will Produce an elongation as much as 8 ft.2 The effects Of such factors can be minimized through the use of care in depth measurements, the application of corrections based on experience, and continuous calibration or checking. The fact that different methods and different tools are used to determine the depths of formations in wells will sometimes give rise to a difference between measurements. It is evident that an important requirement in a well is the ability to locate at will any subsurface point. While absolute depth measurements have ion in recent years, it is reassuring to have other means to verify, for example, that a casing is perforated at a particular place with reference to a zone within a formation. Such a check on measurements may be had by placing a reference marker at a point known with respect to the electrical log of the borehole. That point is usually chosen to be in proximity to the 'One to be perforated. Thus, only short in depth measurements are made and any inaccuracy becomes very small and of minor importance' The use of reference markers located at fixed points predetermined in each zone where future operations are contemplated enables the operator to position any tool

Jan 1, 1948

While specific definitions of the main categories of mineral reserves and mineral resources are becoming well established through the efforts of the Australasian Joint Ore Reserves Committee (JORC) and the Combined Reserves International Reporting Standards Committee (CRIRSCO), there has been perhaps less attention paid to the standardisation of language used in the definition and reporting of Mineral Exploration Results and a clear understanding of the transition to Inferred Mineral Resources. This is an area of significant importance to small and medium sized enterprises in the mineral exploration sector as it represents in many cases the only tangible information by which the reader or potential investor can evaluate the future potential of such enterprises. By its very nature information in the Mineral Exploration Results category is incomplete, and frequently complex, and it is open to a broad range of interpretation by readers of various competency levels and disciplines. Many will have a short-term speculative view rather than a long-term perspective, with others out deliberately to misrepresent the information, and as such it can have an enormous impact on investment decisions if the risks associated with this information being reported are not fully understood. Authors of reports on Mineral Exploration Results, who may be Competent Persons or company directors, have to put themselves in the shoes of the reader of the report, second-guessing if you like what the reader will understand by a report, which in many cases will be of a highly technical nature. This raises reporting dilemmas and questions that require to be understood and addressed. Looking at reports on Mineral Exploration Results from the other side, readers have a degree of responsibility as well, particularly if they engage in an advisory or communications role. The tendency of commentators, journalists, analysts, and bulletin board posters to over-exaggerate the significance of a particular exploration result is all too familiar. Questions arise here as well about whether there should be more regulatory supervision and control exercised over those who use this information, all of whom greatly influence investment decisions, and many of whom have no idea there is a Reporting Code, far less an understanding of it. Examples are given and questions raised to illustrate the dilemmas surrounding the reporting of Mineral Exploration Results. In order to retain credibility with markets it is incumbent on companies to be transparent, not to be selective and to report all material information. On the other hand, information has to be taken and read in its proper context in order to avoid fuelling dramatic and unjustified company share price escalation. Timing of course is another factor that can affect the market price of shares, which may be beyond the control of those making the reports. Emotive and imprecise language, however, when reporting Mineral Exploration Results, coupled by speculation, can trigger damaging short runs on shares and destroy credibility where formerly there was long-term promise. The paper will review how Mineral Exploration Results are dealt with in various jurisdictions, and conclude that there has to be a balance between prescription and the tempering of undue optimism on the one hand, and the entrepreneurial spirit, which the industry needs, on the other.

Jan 1, 2002

By Charles H. Moore

In the study of the properties of rutile pigments it became apparent several years ago that certain physical and optical properties could not be determined on particles of pigmentary size. Since reflected light is the dominant type which reaches the eye from small particles, the true color of pure rutile was not known. Most rutile pig-ments are acicular in habit, elongated parallel to the "c" axis. It was considered important to know the nature and tone of light transmitted, for example, by a basal plate. Further, as shown by spectrophotometric curves, there is a very strong absorption of light of 4000 A as measured on particles with random orientation. It would be interesting to see whether this absorption position varied with predetermined and selected orientations. Also, since the behavior of titanium pigments in a vehicle is important, a knowledge of the surface wettability of single crystals by various media should prove very fruitful. Finally, the optical properties of rutile are such that it should show, in a single pure crystal, greater fire and brilliance than the diamond. Mineralogists had long speculated that this would be the case and curiosity was strong to produce a single crystal large enough to cut. In light of the above, a project was initiated for the formation of single crystals of rutile. Method of Formation of Rutile Single Crystals Fortunately, purification of TiO2 produced from both titanium tetra-chloride and titanyl sulphate solutions had reached the stage where spectro-graphically pure starting material could be made. Spectrographic analysis of the feed material used in the initial experiments is compared with the present feed material in Table 1. It is apparent that the present large scale purification is approximately as good as the original experimental, small scale purification. Verneuil1 produced synthetic ruby and corundum in 1904 by the well-known flame fusion process, which today bears his name. Except for mechanical improvements the present commercial production of synthetics by flame fusion is essentially unchanged from his initial method. His burner consisted of an inner orifice through which was fed the feed material and oxygen. Surrounding this was a larger outer orifice through which was fed hydrogen at lower pressure. This arrangement consists then of a lance of oxygen burning in an atmosphere of hydrogen. The proportions of hydrogen to oxygen usually used in corundum production is about 3:1, providing there is sufficient temperature to reach the 2050.°C required for the fusion of alumina. From work done in the Titanium Division Laboratories2 and from the published work of Erlich3 it was known that rutile appears to lose oxygen near its melting point and that it would not be possible to grow single crystals in a strongly reducing environment. Consequently, in order to determine whether single crystals could be grown at all, an Airco oxygen-acetylene torch with

Jan 1, 1950

By R. A. Generes, H. C. H. Darley

Laboratory tests showed that at elevated temperatures a reaction takes place between all metal hydroxides and clay muds, which results in a thickening or solidifying of the mud, the extent of which depends on the nature of the ingredients. Calcium hydroxide gave the strongest solidification whereas barium hydroxide only caused a mild thickening, indicating that the use of barium hydroxide muds instead of lime muds would be a good way of preventing high-temperature solidification. It was found possible to prepare barium mud in the laboratory with caustic soda and a thinner in the same manner as lime muds, and these barium muds had the same or better toleration of high solids content, resistance to salt contamination, and low gel strengths as the corresponding lime muds. Three field trials have been made with barium mud. The principal difficulty encountered was in determining the correct proportions of the tourly treatments required to maintain low gel strengths. A satisfactory systern was finally developed, and low gels were maintained throughout the third test. The wells on which the trials were made were not carried deep enough to test the resistance to solidification adequately, but oven tests at 350°F were made periodically and no tendency to solidification was noted except immediately after severe cernent contamination had introduced excessive amounts of calcium into the system. Although barium hydroxide costs considerably more than lime, the total mud costs were as low, and on the last well significantly lower, than the average cost of lime mud wells drilled in the vicinity. INTRODUCTION The advantages of repressing dispersion and hydra-tion of clay cuttings carried in the mud, particularly when drilling through thick clay formations, are well recognized. This repression is generally achieved by the use of lime, and lime muds have in consequence the desirable characteristics of high toleration of solids, low thixotropy, and good resistance to contamination. They have, however, the disadvantage of high-temperature solidification. This phenomenon has been described in detail by Gray et al, who have shown that it is the result of a chemical reaction between the hydroxides and the clay minerals. The work described in this paper was undertaken to find a substitute for lime which would not cause this solidification. LABORATORY EXPERlMENTS The principal positive requirement for a substitute for lime is that it should repress the hydration and dispersion of clay. It is well known that monovalent cations promote hydration while polyvalent cations repress it. Therefore, a few representative polyvalent salts and hydroxides were tested to determine whether they could be used as substitutes for lime. Their efficiency at repressing hydration and dispersion was measured by means of the clay-volume test. It has been shown elsewhere' that this test is a good measure of degree of dispersion of clay in suspension and that hydration accompanies and correlates with dispersion, so that measuring one measures the other. The test is made by centrifuging a 1:100 mixture of mud and 1-N NaCl and observing the volume of sediment—the greater the volume, the greater the dispersion. The tendency to caux solidification was measured by heating the muds in pressure vessels for 16 hours at 150°F and 370°F. An approximate quantitative

Jan 1, 1957

By N. E. Grosvenor

Several methods have been proposed for determining the tensile strength of rock. These have been tried out over the past several years, but the results have been erratic and of doubtful value. The tensile strength of rock is its weakest property, and this property apparently enters into all failure phenomena, whether underground or on the slope of an open pit. Therefore, it is essential that detailed quantitative information is known about the tensile strength of rock if the design engineer is going to select the proper pit slope, pit orientation, or orientation of underground workings so as to give the most economical and safest mining condition. This quantitative information may be used to orient the pit in such a manner as to allow steep slopes along two sides. This information possibly may be used to orient the direction of either underground workings or open pits so as to decrease powder consumption and to increase blasting efficiency. Hence it is of prime importance that a method of determining accurately the tensile strength of rocks be developed. The U. S. Bureau of Mines states' that no standard methods have been proposed by the ASTM for testing the tensile strength of rock. The method described in the Bureau publication is said by them to be unsatisfactory. A similar test that has been used in our laboratory in place of the USBM test is shown in Figs. 1 and 2. h this test the core is placed in a set of grips that has been designed for one particular size core. The grips are designed to distribute the stress around the core if they are tightened correctly. A universal joint or a flexible cable may be used in conjunction with the apparatus to prevent bending or twisting of the specimen. The main difficulty encountered with the system shown is the failure of the specimen within the grips. The possible cause of the failure within the grips may be due to a stress concentration set up by the uneven tightening of the grips. This method can be used only for tests on cores, and even then has been found to be totally unsatisfactory because of the failure within the grips. The U. S. Bureau of Reclamation has been using a test similar to the sketch shown in Fig. 3. Sulfur is cast around each end of the specimen to form a bearing surface and then a ring grip is used to apply a tensile stress. The grips are in contact with the sulfur cast and do not touch the specimen. This method is unsatisfactory, apparently because a large number of the specimens appear to break within the sulfur cast. Professor Wuerker of the University of Illinois uses the test shown in Fig. 4.' Professor Wuerker states2 that this method has given definite and reproducible results with the weakest as well as with the strongest rocks. The test is a supplement in all cases where cores cannot be obtained. The principle and equipment are the same as for the test for tensile strength of hydraulic-cement mortar. Soft

Jan 1, 1961

By X Z. Sun, N Jiang, J H. Zhao, C X. Wang, L Y. Bai

In backfill grouting for underground coalmines, the filling materials strengthen the caving rock and support the overlying strata to reduce surface subsidence. The broken roof strata fail and collapse during mining operations without appropriate supporting measures being taken. It is difficult to perform continuous backfill mining on the working face of such roofs using the existing mining technology. Therefore, in order to solve the above problems, fly ash and mine water are considered as filling materials, and flow characteristics of fly-ash slurry are investigated through laboratory experiments and theoretical analyses. Laws governing the diffusion of fly-ash slurry in the void of caving rock masses and in the void between a caving rock mass and a basic roof are obtained and verified. Based on the results obtained from the above analyses and field conditions at the Zhaoguan coalmine, Shandong Province, China, a cave backfill grouting system of the hauling pipeline is developed and successfully tested at the 1703 working face. The results demonstrate that a filling rate of 43.46 per cent is achieved, and the surface subsidence coefficient of the grouting process is found to be 0.475. Compared to the total caving method, the proposed system is found to achieve a reduction rate of 40.63 per cent. This effectively helps in lowering the value of the surface subsidence coefficient. Fly ash and mine water, considered as primary materials in this study, also play a significant role in improving the air quality and water environment.

Nov 29, 2022

The Mine Safety and Health Administration (MSHA) defines an independent contractor as "any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine." Contractors that perform specific types of work are required to report the number of employees who perform work at coal mines and at noncoal mines.

Jan 1, 2004

By T. A. Edison

A distinct hydrocarbon maturation anomaly coincides with the Gold Acres open pit, Nevada (Figure 1). Both atomic hydrogen to carbon (H-C) ratios and reflectance measurements of contained organic matter indicate significantly higher maturity in samples collected within the confines of the open pit than in samples from the surrounding region (not shown in Figure 1).

Jan 1, 1987

By C. K. Eilerts, J. D. Ham

Laboratory research has been conducted to evaluate the characteristic effects of condensate saturation on the mobility of gas in typical reservoir rocks. A pump with two pistons provided phases in equilibrium at controlled flow rates and constant liquid-vapor volume ratios. Core samples were tested in a holder that permitted sealing steady-state phases in the pore spaces under flow test pressures for weighing with sufficient precision to give an accurate measure of the attained saturations. Parameters of the study were pressure, apparent velocity, flowing liquid-vapor volume ratio, fluid composition, core material and length-to-diameter ratio. Tests were conducted at 515 and 1,515 psia to determine the effect of pressure on the mobility-saturation relationship. Influence of the apparent velocities 0.30, 0.15 and 0.07 cm/sec and of five liquid-vapor volume ratios from 0.0001 to 0.01 was determined at 515 psia The principal fluid system was nitrogen and and separator liquid from a Gulf Coast condensate, but the effect of a condensate of different viscosity was also determined. The significance of a possible concentration of liquid near the outlet end of the test cores was investigated. Core materials included a consolidated sandstone and a low-permeability limestone. Relative mobility and liquid-vapor volume ratio relationships are concluded to be dependent on pressure, saturation and, to a lesser extent, on velocity. For each porous medium and fluid there is a minimum saturation essential to two-phase flow, and high velocities of flow have only limited effect on saturations in this range. INTRODUCTION It is now recognized that knowledge of the availability of a reservoir gas — the period that gas may be recovered from a reservoir at a given rate — is as important as the estimate of gas in place. When reservoir conditions are such that pressure decline owing to production will result in retrograde condensation, liquid saturation can increase in the structure around the production well in a way that may restrict flow capacity, and hence future availability. l Based on a numerical solution of transient radial flow of single-phase gas-condensate fluids, 2 a program for computing the accumulation of condensate in a reservoir and the effect of this condensate on deliverability has been developed. During this development a need evolved for data that described the influence of pressure, velocity of flow and condensed liquid on mobility as recovery progressed. This paper presents the results of experimental investigation to obtain insight into the mobility relationship at reservoir pressures of gas-condensate fluids. A core holder for flow tests at reservoir pressure was developed to weigh the core and its fluid contents under pressure to determine saturation. A specially constructed pump was used to drive a two-phase fluid through the core until a steady state prevailed. The core was used as a differential device, and properties measured were intensive rather than extensive. APPARATUS Fig. 1 shows a schematic representation of the major pieces of equipment used in the mobility determination. The weighable core holder is connected to a two-piston, constant-displacement pump. Attainment of steady-state flow is indicated by stability of the flow differential read from the high-pressure manometer. WEIGHABLE CORE HOLDER An important part of the data needed was the mobility-saturation relationship. This required that mobilities and saturations be measured at pressures, flow velocities and liquid-vapor volume ratios characteristic of condensate reservoirs.