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By William J. Campbell

One of the principal objectives of the Bureau of Mines program for developing super refractory materials is to obtain fundamental data on the physical properties of refractory oxides. This particular investigation obtained accurate thermal expansion coefficients for alpha alumina and evaluated, critically, those coefficients with other published values. High-temperature X-ray diffractometer measurements, by the Bureau, showed that alpha alumina expands anisotropically with expansion parallel to the c axis approximately 10 percent greater than parallel to the a axis. Thermal expansion characteristics of four different alumina samples were determined up to 1,200° C.; the results are presented in both tabular and graphical form. The combined random and systematic errors in the measurements are considered less than 3 percent above 500° C, and approximately 2 percent at 1,000° C. No differences in expansion were observed between the samples or between the heating or cooling cycles.

Jan 1, 1961

By J. W. Cox, W S. Jones, A E. Chase

For a long time the Oil Industry has been looking for a logging tool which can determine the quality of the cement job behind casing. Older methods such as Temperature Surveys and Radioactivity Surveys might detect the presence of cement behind the casing, but short of production tests, it was impossible to tell that the producing zones were adequately sealed off from adjacent zones. A new logging method, which is called the •Cement Bond Log, operates on the principle that a sonic pulse transmitted by the casing is greatly attenuated when the casing is strongly bonded to an outer annulus such as cement. The down-hole tool consists of a source of sonic energy which is detected by a receiver situated a few feet away from the source. The amplitude of the detected energy is measured and the resulting signal transmitted to the surface where it is recorded versus depth. Amplitude is a function of attenuation and thus the log is readily interpreted.

Jan 1, 1961

This Institute, by nature of its charter, draws on various persons in the mining and metallurgical world of Australasia for its President from year to year, and consequently when the presidential address is given by one of these people the topic. which they generally select is a topic to which they are accustomed and on which they are able to speak with authority.As most of you know, my prime object in life has been concerned with steelmaking, so tonight you can steel yourself to the thought that you are going to be spoken to about steelmaking.Even if that were not the case, and were I not particularly interested in steelmaking, I think it would be appropriate to look at steelmaking in a broad sense on a basis of pure metallurgical interest, because the steel industry is going through as big a revolution today as it went through something over one hundred years ago when Bessemer made a theory become a fact.Bessemer, and as the Americans prefer to think Kelly, separately conceived the idea of blowing cold air through molten pig iron, and, contrary to the then general belief, this did not result in cooling of the metal but succeeded rather in heating it, and in burning out of the rather crude pig iron the impurities which prevented it from becoming a ductile metal.For many years before this, steel had been made in a very small painstaking way by what was known as the crucible process. Benjamin Huntsman is credited with having developed the crucible steel making process to a stage where it could make a reliable and trustworthy product, but he...

Jan 1, 1961

By Perry G. Cotter

The objective of this investigation was to synthesize and investigate the properties of a high-temperature refractory material based on a combination of boron, silica, and magnesium. A magnesium-thermic reaction was used for the synthesis. X-ray examination of the product indicates that the crystalline portion of the composition is a combination of magnesium borides, magnesium silicate, and magnesium orthoborate. Chemical analysis of a representative sample shows, in weight-percent, boron 17.6, silicon 23.9, magnesium 17.8, and chromium 0.5. The balance is largely oxygen. The composition is resistant to high temperatures under oxidizing conditions and is stable in water, hydrochloric acid, and hydrogen. It has a low density (less than 3 grams per cubic centimeter) and a hardness value in the range of quartz. It has a melting point above 1,700° C. and can be hot-pressed to shape in the temperature range between 1,200° and 1,350° C. The properties described in this paper indicate that the material may have some uses as a high-temperature refractory, and because of its boron content it may have some value as a thermal-neutron-absorption material.

Jan 1, 1961

By Bernard Porter

The solubility of UO2 was determined at 1,250° C. in ternary melts of UF4 and BaF2 with CaF2, LiF, and SrF2. The solubility of Ce02 was measured at 800° and 850° C. in a solution of CeF3, BaF2, and LiF. The amount of La203 which dissolves at 950° C. in a binary mixture of LiF and LaF3 and a ternary of LiF, LaF3, and BaF2 was also measured. In each case, the amount of soluble oxide was mound to be less than 5 weight-percent. A procedure was developed for filtering fused, oxide-saturated fluoride melts in order to obtain a representative sample for chemical analysis. The oxide content of the samples was determined by an inert-gas fusion procedure.

Jan 1, 1961

By C. E. Baltzer

This paper highlights the position of coal supply in regard to the requirements for electric-utility operations. The text and the appended tables outline the trend of thermal power development and fuel use in the electric-utility industry. Mention is made of several argumentative factors influencing the use of coal in relation to competitive oil and gas, and of the importance attached to developing a realistic understanding of the respective problems faced by the supplier and consumer of coal. * * * TREND OF" THERMAL POWER DEVELOPMENT T HE RATE OF ADVANCE in thermal power has been significant during recent years, particularly in the Atlantic Provinces, the Prairie Provinces, Ontario, and British Columbia. While dependence on thermal power in Quebec and the Northern Territories is less than in the remainder of Canada, these regions also eventually will have need for increased amounts of such power.

Jan 1, 1961

By L. A. Panek

During the past three years, USBM has developed an apparatus and technique for direct measurement of existing pressure and change of pressure in mine rock. This relatively simple and inexpensive monitor is reliable for months after being installed. It is used to determine shift of ground pressure created by different sequences of mining, to ascertain the cause of rock failures, and to evaluate the need for artificial support. The technique has been employed to measure pressures in limestone, greywacke, concrete, diabase, and soft iron ore. When rock is subjected to a load it is deformed. Ordinarily this is observed in a mine as the displacement of one point with respect to another—the deflection of the roof, which may be observed as a convergence between roof and floor; or the extrusion of material from the rib, which may be observed as a decrease of the distance between the rib and the post of a timber set. The effect of excessive pressure may be a rockburst if the rock is strong, or it may be squeezing ground if the rock is soft. Some desirable effects of high stress (high in relation to strength) are the caving of roof in a longwall mining operation, the caving of ore in block caving, and the decrease in mechanical energy required to break down the mineral seam in a retreating pillar-robbing operation. In any case, whether the observable effect of rock load is desirable or undesirable, it is a displacement, and depends on the following four factors: 1) The structure—the size and shape of openings, pillars, and linings, the geologic bedding and jointing. 2) The mechanical properties of the rock—prin-cipally the strength, modulus of elasticity, and flow characteristics. 3) The load or applied stress—primary sources are the weight of superincumbent rock, which increases with depth, and unrelieved tectonic stresses; secondary sources are redistributed pressures caused by other nearby openings, especially large mined out zones (rock pressure depends partly on the rock structure created by mining). 4) Duration of load, related to the length of time the opening is exposed. CONTROL OF ROCK DISPLACEMENT Rock displacement can be controlled by control of these four factors. Consider now the means of exercising such control over these factors. Control of the structural features is obviously possible to a great extent, as such control is exercised largely by choosing the method of mining and the methods of natural and artificial support. Rock properties vary, even within a particular mine, but they are controllable only in the limited sense that control may be exercised by choosing the beds or zones to be mined so that rocks with undesirable properties will not occupy critical positions within the rock structure created by mining. Rock pressure is the most complex of the four factors through which ground control can be achieved because it is invisible, difficult to measure, and poorly understood. Rock pressure is controllable only to the extent that control is exercised on the rock structure created by mining. Considering openings within a particular mine, time of exposure varies, and is readily controllable because it is easily measured and easily understood — the longer an opening stands, the greater the likelihood of failure or excessive convergence. Control is exercised by choice of an appropriate sequence of driving openings of different classes, such as haul-ageways and rooms, which are required to remain well supported for different lengths of time under different conditions. Again, control is exercised through the method of mining. All controllable factors can be controlled by proper design of the mining method. The orientation and relative positions of the mine workings and the sequence of their excavation are likely to be much more important to ground control than is the design of artificial support. This implies that the major decisions in regard to ground control are made, knowingly or not, at the time the mining method is chosen. WHY MEASURE ROCK PRESSURE In addition to restrictions on the several factors, control implies the measurement of these factors in some sense, whether only qualitatively by visual observation, or by actual quantitative determination with a measuring instrument. Rock pressure is the most difficult of these factors to measure, largely because of the interaction between the measuring device and the rock. Nevertheless, the quantitative

Jan 1, 1961

By F. E. Armstrong

This report describes development and application by the Bureau of Mines of techniques and instruments for using radioactive inert-gas tracers to determine flow paths through petroleum reservoirs that have natural fracture systems and for which water injection has been selected as the stimulative production method. A field test was made to prove the techniques and evaluate instrumentation. The feasibility of applying the techniques and instruments to the solution of reservoir problems in other stimulative methods of production also is discussed. Oil commonly is displaced from sandstone host rocks by the action of a driving force that causes the oil to move through interstices of the rock and into production wells. In addition to the requirements of oil being trapped within the sand pores and the presence of an effective displacement mechanism, the rock itself must have adequate permeability to permit flow of oil and other fluids.

Jan 1, 1961

By J. G. Thomson

Development of the Canadian North, a subject of growing national interest, must in part await the development of better forms of trans-port. The estimated 500,000 square miles of muskeg terrain in the north combined with the" scarcity of roads make essential the early development of special purpose muskeg vehicles. Good progress has been made in the last eleven years in classifying muskeg and some progress has been made in determining its mechanical properties. Limited travel is now possible through the use of special purpose tracked vehicles which have been built without adequate design data. A program to provide data which can be used to optimize muskeg vehicle designs began in 1957. The results of the second phase of this pro-gram are presented in this report. It is shown that vehicle performance in muskeg is directly related to the mechanical properties of the muskeg. Further, it is shown that good de-sign practice for tracked vehicles expected to operate in snow, sand, soft clays and loams is also good practice for muskeg vehicles. All indications are that muskeg mechanics is properly a part of conventional soil mechanics.

Jan 1, 1961

By A. N. Fried

With the growing importance of fluid injection in recent years, the petroleum industry has been investigating and field- testing a variety of new methods designed to modify the physical properties of reservoir oil to improve the efficiency of gas and water injection. These procedures include condensing-gas drive, LPG (liquefied petroleum gas) injection, alcohol-slug process, high-pressure-gas displacement, detergent-solution flooding, and in situ combustion (30, 37).3 A new and different method to increase the effectiveness of gas and water injection has been tested by the Bureau of Mines, Consideration of both fundamental and practical factors that operate to limit the oil recovery attain- able by conventional oil-displacement mechanisms led to the concept of a displacement mechanism called the foam-drive method. This report describes the experimental study that tested this concept in the laboratory.

Jan 1, 1961

By D. A. Pirttinen

The promotion of improved coal quality for thermal generation can benefit our national economy. The construction of electric generating facilities in Canada is expanding at a rapid rate to satisfy the demands of a rising population and new uses for electrical energy. With remaining economic water power resources in the process of development, generation from thermal sources continues to grow. The increase in thermal capability has been somewhat arrested by a de-pressed economy, widening of inter-provincial and state transmission networks and decisions to exploit certain water resources before high capital investment is further in-creased by rising construction costs. The introduction of extra high volt-age transmission lines will further delay thermal generation planning, but in due course, when the effects of restrictive factors have been dissipated, steam-electric generation from fossil fuels will rise to considerable proportions. In time, nuclear sources will contribute a growing share to thermal power, but, it is doubtful if nuclear participation will ever displace conventional fuels for steam rising, unless it can be adapted to operate efficiently for variable outputs in peaking service. It appears certain that fossil fueled

Jan 1, 1961

By Erwin A. Morlan

Present methods of boring large hole mine openings are briefly reviewed. Factors that influence the design and choice of down-the-hole equipment for rotary drilling large holes are discussed. With formation drillability taken as a starting point, graphs and charts are given as an aid in the selection of bit load, circulation system, flow rate, drill stem, cutter design and rotary speed.

Jan 1, 1961

By E. S. Anolick, Joseph Singer

The magnetic after-effect, in the form of time decay of permeability (l/µ), has been used to obtain independent data on the solubility of' carbon in pure iron. The results differ slightly from the solubilities obtained through internal -friction experiments. The mechanism of the time decay being the magnetic analogue of internal friction, it appears necessary to explain the observed discrepancies, and some suggestions are made. THE purpose of this work was to establish the reliability of the time decay of permeability as a measure of dissolved interstitial in the body-centered-cubic lattice, and further, to establish techniques suitable for such measurements with samples of a form convenient for various other measurements. This particular sample form was the "epstein" strip, i.e., 25 cm by 3 cm by 0.035 cms. While the general conclusions are not limited by this geometry, there are two aspects of the samples that may be relevant: a) texture, and b) grain size, which ranged generally from 1 to 10 mm. Effects due to these two possible parameters were thought to be small and were not investigated. Calibrating the time decay technique and the other experimental procedures by measuring the solubility of carbon in pure iron suggested itself because of the accumulation of data on this subject through the related technique of the internal friction'; The essentials of this report have been published in a somewhat condensed form.5 Since then some additional data have been taken. It is the purpose of this paper to add these data and to provide more complete description of the experimental techniques than was possible then. The time decay of permeability is a form of the magnetic after-effect.6,7 Permeability is measured immediately after demagnetization (µº) and also long after (µ8). The time decay, ?(l/µ), is the difference 1/µ8 - 1/µ0 and has been considered to be proportional to the concentration of a dissolved interstitial6,8,9,12 The relaxation time! 7, is characteristic of a particular diffusion, and affects the permeability as follows: where he being the activation energy for diffusion of the interstitial. Reference is made to the works of snoek6 and Neel7 for a complete discussion. A brief exposition of the principal ideas may be in order here, as follows. On the basis of the simplest model, resistance against domain wall motion increases with time after demagnetization due to the diffusion of interstitials to preferred sites created by the magnetostrictive tetragonolization under the strong magnetic field. Thus permeability, measured with a small field after the abrupt removal of the large field, will continuously fall with the process of diffusion of the interstitials, and the total "time decay" (or "time decrease") should be proportional to the amount of interstitial in solid solution. In the present report, use is made only of the total time decay rather than of the nature of the progress of the decay; the only problem involved in this approach is the need for assurance that only one interstitial is contributing to the effect as used. It is felt that the special use made here of the total time decay warrants the conclusions. Other work has been going on elsewhere on the detailed study of the nature of the time decay.8'9 EXPERIMENTAL A) Materials—12-lb ingots were made in a vacuum furnace from high-purity iron and by a series of hot and warm reductions were brought down to 14-mil strip. This was cut into 25-cm epsteins. The pure iron was decarburized at 750 °C by hydrogen. The time decay measurement for the decarburized iron (see below) indicated a satisfactorily low starting level of interstitials. Grain growth to grain sizes of 1 to 10 mm was produced in the pure iron by a 700" anneal in hydrogen after a critical reduction of about 7 pct as suggested by previous trials. No measurement of texture in the pure iron was made. The grain size was taken to be large enough to be beyond any sharply critical size regarding solubility. B) Infusion of Carbon—Since the permeability measurement required about two dozen epsteins, a special method of carbon infusion had to be developed to ensure homogeneity of infused carbon. This was accomplished by setting the samples edgewise in a

Jan 1, 1961

By G. W. Govier

The origin and limitations of the conventional and empirical equation for the interpretation of the results of back pressure tests on gas wells are discussed. Difficulties in data interpretation arise from many causes, including Jack of flow stabilization, uncertainties in connection with the friction calculation, and the effect of turbulence near the sand face in the reservoir. A procedure is developed to ac-count for the turbulence effect. This is based upon the theoretical equation for laminar steady state flow and current knowledge of turbulent steady state flow. The procedure involves the expression of the equation for combined laminar-turbulent steady state flow in terms of a turbulence contribution factor. This factor. is shown to be dependent mainly upon the flow rate per unit of pay thickness and the reservoir permeability. The method of interpretation permits the use of judgment based upon the theory and present day under-standing of laminar-turbulent flow and is considered an improved method

Jan 1, 1961

By W. R. Huff

This report describes the development and operation by the Bureau of Mines of a pilot plant designed for using high-volatile A bituminous coal-in-water suspensions as a source of preheated coal and superheated steam in the pressure gasification of coal with oxygen. Figure 1 on page 2 is a block diagram of the integrated gasification process, in which a total of 70 tons of coal was fed from slurry and gasified. The present work included (1) development of equipment and methods both for mixing pulverized coal and water to produce slurry and for pumping and metering the slurry at gasification pressure; (2) development of equipment for heating the flowing slurry and, because slurry that can be pumped produces more steam than is necessary as a gasification reactant, developing equipment for removing and metering the excess steam; and (3) demonstration of the process under actual gasifier operating conditions, at a coal rate of about 800 pounds per hour and gasification pressures in the range 100 to 300 pounds per square inch gage. By using the forced-convection principle, a flow of slurry made from a caking, high-volatile A bituminous coal can be continuously heated to 600° F. in a coil-type heater. The flow rate and concentration of the slurry and the temperature gradient along the length of the heating coil must be closely controlled. In a radiant-type heater, involuntary reductions in flow rate, even momentary, can lead to coking and plugging of the heater coil.

Jan 1, 1961

By C. P. Mabie

This report summarizes studies by the Bureau of Mines in developing a simple method for estimating the phosphorus pentoxide (P205) content of finely ground sedimentary phosphate ores and beneficiated products. The method used involved leaching, filtration, and precipitation. The Bureau found that measurement of the volume of ammonium phosphomolybdate precipitate obtained from samples containing 16.8 to 37.7 percent P205 and the use of an appropriate calibration curve permitted estimates of percentage of P205 content accurate within ± 1.1 to ± 2.6 percent, respectively, at the 95-percent confidence limits. Incidental to mineral dressing and petrographic investigations of western phosphate ores in 1959, the Bureau of Mines undertook development of a simple process-control method for rapid on-the-spot evaluation of phosphate-mineral recovery. Because of the fine-grained and obscure character of western phosphate ores, chemical, rather than microscopic or petrographic, techniques were investigated. The described method involves acid decomposition of the ore or product, filtration, addition of ammonium molybdate reagent to the filtrate, and centrifuging and measuring the volume of yellow ammonium phosphomolybdate precipitate produced.

Jan 1, 1961

By V. M. Benson

A simplified, routine method for determining lithium in lithium-bearing rock is presented. The sample is decomposed by repeated treatments with nitric, hydrofluoric, and perchloric acids. Since this procedure does not appreciably dissolve beryl, interference by beryllium (the principal interfering cation) is minimized for most samples. The salts are brought into solution with water and enough citric acid-ammonium citrate buffer is added to make the final volumetric dilution 0.20 M with respect to citrate. The addition of citrate greatly reduces anion interference in the hydrogen-oxygen flame, slightly increases the intensity of the lithium 671 millimicron emission line, and reduces the effect of most of the interfering cations to the extent that analytical separations are not necessary. The accuracy of results of single determinations of lithium in a pegmatite containing spodumene, lithium-bearing mica, and beryl are approximately equal to that obtained by other flame methods, INTRODUCTION This investigation was undertaken in Bureau of Mines laboratories to develop a reliable, rapid, routine analytical method for determining lithium in lithium-bearing minerals. The requirements of the procedure were that the method should be applicable to the analysis of a variety of lithium-bearing ores and test products, and the results would be reasonably accurate for materials containing 0.05 to 8 percent Li20.

Jan 1, 1961

By J. I. Budnick, W. B. Ittner III, D. P. Seraphim

A reliable technique has been developed for producing single crystals of tantalum in the form of small diameter wires. By suitably heat treating these and polycrystal samples, first in an oxygen atmosphere and finally in vacuum, it has been found possible to reduce residual resistivities to 10-3 microhm-cm. The purity of these samples is thus comparable to the purities obtained in zone-refined silver, copper, and aluminum. THE growth and purification of pure single crystals of the transition metals is, in general, difficult. The high melting and annealing temperatures of these metals make it necessary to employ rather special techniques in any crystallization process. In addition, the transition metals show a great affinity for and are easily contaminated by nitrogen, oxygen, and carbon. Recently, however. a number of investigators have been successful in growing,

Jan 1, 1961

By K. C. Dean

The combination of flotation and chemical processing methods presented in this report of the Bureau of Mines enabled treatment of typical low-grade ferberite ores from the Boulder County, Colo. area, to produce specification-grade synthetic scheelite. The overall recovery from ore to synthetic scheelite was 87 percent, based on a flotation recovery of 93 percent and a similar recovery in chemical processing. Preliminary mineral dressing studies revealed that the physical and mineralogical nature of typical ferberite ores precluded high recovery of tungsten in plus 60-percent-W03-grade products by these methods. Therefore, the flotation research was focused on attaining plus 90-percent recovery in a concentrate containing 10 percent W03. Detailed studies were made (1) to establish optimum grinding conditions for obtaining adequate mineral liberation, (2) to develop collecting and modifying reagent combinations that would enable controllable selective flotation, and (3) to define the influence of different pulp solids, temperature, pH, and time for conditioning and for the rougher and cleaner flotation stages.

Jan 1, 1961

By E. G. King

Sodium-aluminum and calcium-aluminum silicates are important rock-forming minerals. While many of them are of only theoretical interest, several are of practical importance--as ceramic raw materials and as potential future sources of aluminum. Heretofore, thermodynamic data for these minerals were incomplete; and in many instances missing data were difficult to estimate reliably. This has seriously hampered thermodynamic calculations pertaining both to the natural formations of these minerals and to their decomposition in sintering and fluxing reactions. This paper reports the results of the Federal Bureau of Mines measurements of low-temperature heat capacities of four crystalline silicate minerals--dehydrated analcite (NaAlSi2O6), hexagonal anorthite (CaA12 Si208), lawsonite (Ca2Al2Si2080?2H20), and leonhardite (Ca2Al4Si8C24?7H2O). It augments previous similar measurements of related minerals, which were summarized recently.4 The measured heat-capacity data were used to derive entropy values for the four minerals at 298.15° K. Some relations between these entropy values and those of other similar minerals were discussed. These relations illustrate the difficulty of estimating entropy values of tertiary (or higher) silicates.

Jan 1, 1961