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By Tribhawan N. Srivastava

The Henderson Mine started production in 1976 utilizing a unique, push-pull, mine ventilation plan. As the mine expands in size, the mine ventilation requirements will increase and a more comprehensive system for maintaining ventilation will be needed. A computer simulation study was completed and has resulted in a revised, systematic, mine ventilation plan which is being implemented as mine development proceeds. Based on the computer simulation study, the new ventilation plan takes into account mining of the orebody simultaneously from both the 8100 and 7700 production levels. Present experience and empirical data indicate that volumes of air needed to adequately ventilate both production levels cannot be obtained utilizing the existing mine layout. The total volume of air needed for the mine excluding haulage tunnel will increase from 708 m3/s (1 500 000 cfm) to 1652 m3/s (3 500 000 cfm), thus a new No. 5 exhaust shaft and connecting drifts are being developed to expand the mine ventilation system to service both production levels. The original ventilation plan for the 7500 haulage level was to bring air from the No. 2 and No. 3 intake shafts and exhaust it through the 94X raise to the 8035 exhaust level and then through the No. 1 exhaust shaft to surface. Control of air volumes in loading drifts was initially planned to be achieved by air doors and air curtains. Air doors on the 7500 level require large cutouts, expensive installations and constant maintenance. The computer simulation study indicates that air- flow in the 7500-level production drifts can be con- trolled exclusively by air curtains which are less expensive to install and more effective in regulating airflows than air doors. Air from the 7500 level can be exhausted through a new raise to the new 7635 exhaust level and then through the new No. 5 exhaust shaft.

Jan 1, 1982

Jan 1, 1910

By Charles Hawes

WHEN sulfur is encountered in objectionable amounts, it is regarded as the most trouble-some element for the mine operator to control. It exists in two conditions in iron ores, as sulfide in iron pyrites and as sulfate in gypsum and barite. The sulfate radical (SO,) may also be linked to one or more of the several other elements found in the iron ore compound. The only dependable method for the de-termination of sulfur, particularly when found in the insoluble residue, has been the so-called fusion method. This is a long and tedious process involving several hours for its completion. In looking for a more rapid method which would be .applicable to all iron ores, the writer investigated the work of M. Groger1 who in 1881 showed that by heating pyrite with iron out of contact with air, the pyrite is reduced to iron sulfide and from the latter all of the sulfur will be given off as hydrogen sulfide gas on treat-ment with hydrochloric acid. FeS2 + Fe = 2 FeS FeS + 2 HCl = FeC12 + H2S In 1891 F. P. Treadwell2 not only confirmed the results of M. Groger but also found that iron powder would reduce to sulfide the sulfate radical of any substance, including barite, if not found in excessive quantities. The writer found this to be true and developed a method, in cooperation with F. J. Baker, chief chemist, mining department, of the Cleveland-Cliffs Iron Co., Ishpeming, Mich., for the determination of sulfur in iron ores which is not only very rapid but also accurate. Pure iron ore powder, reduced by hydrogen, gave good results but was found to be very slow in reacting. A high silicon iron with a low sulfur content of 0.012 per cent was found to be. much more active than the pure iron and gave excellent results.

Jan 11, 1927

By M. C. Flemings, R. Mehrabian, G. E. Nereo

Analytic expressions were developed and applied in two preuious papers to predict effects of solidification variables on macrosegvegation. In this paper, experiments are reported to test the analyses quantitatively and qualitatively. Good quantitative agreement is obtained between predicted and measured compositions for the following types of segregation (all experiments were on laboratory-size ingots of Al-4.5 pct Cu alloy): (a) inuerse segregation, (b) composition distribution in ingots solidified with unidirectional heat and fluid flow, (c) simulated centerline segregation, and (d) segregation resulting fro, change in solidification cross section. In addition, qualitative agreement of prediction of theory with experiment is obtained for (a) segregation resulting from sudden change in heat extraction during solidification, (b) centerline segregation in a bidirectionally solidified ingot, and (c) under-riser positive segregation. IN two previous papers,''2 it was shown that a variety of apparently different types of macrosegregation result from the same basic mechanism. This mechanism is the flow of solute -rich liquid to feed solidification and thermal contractions. Analytic expressions were derived and examples given of their application to predict macrosegregation. Calculations were for Al-4.5 pct Cu alloy. In this paper, we describe a series of experiments designed to test results of the foregoing calculations. All experiments were on laboratory-size ingots (weighing 10 lb or less), of A1-4.5 pct Cu alloy, nominal composition. APPARATUS AND PROCEDURE A typical mold and chilling arrangement used for unidirectional solidification is shown in Fig. 1. Before casting, this assembly was placed in an electrically heated air furnace, and heated to 680" to 700°C. When the plaster reached the desired temperature (usually 1 to 2 hr after the furnace temperature), the mold was filled through a funnel extending from the outside of the furnace into the cavity. The assembly, with liquid, was held for several minutes to allow convection to subside. The coolant, either air or water (depending on the desired solidification rate), was turned on and the ingot solidified. With the four sides and top insulated, heat removal for solidification was through the bottom surface, resulting in a fully columnar structure. Design of the casting cavity was varied, as discussed below, to produce desired macrosegregation effects. However, for castings solidified with unidirectional heat flow, the top was always open to the furnace atmosphere and temperature. The bottom sur- face rested on a chill through which the heat was extracted, and all other surfaces were insulated with plaster. In one case to be discussed, the mold design was changed to obtain bidirectional solidification. In this case, two vertical chills were used (on two faces of the mold) and the bottom was insulated. In a last case discussed, that dealing with under-riser segregation, experiments were conducted in bottom-chilled sand molds at ambient temperature. Except for this one case, all experiments were conducted in the electrically heated air furnace as described above. In many ingots, thermocouples were used to obtain continuous records of solidification. In all cases, these were chromel-alumel couples with output continuously monitored on a twelve-channel recorder. Where thermocouples were employed, these were embedded in the refractory mold walls during mold-making so their heads extended to the vertical centerline. Six to nine couples were employed, placed at intervals from the chill. METAL-MEL TING PROCEDURE Aim analysis was A1-4.5 pct Cu; alloy was prepared from high-purity aluminum (99.9 pct Al) and A1-Cu master alloy (50 pctOFHC Copper, 50 pct high-purity Al). The A1-4.5 pct Cu alloy was cast in 5- to 7-lb ingots for subsequent remelting for the macrosegregation experiments. Melting for ingot casting was as follows. After preheating the melting crucible for an hour or more, the charge was melted and superheated to a temperature of 690" to 720°C. After stirring, the melt was degassed with chlorine for 10 min. After stirring again for 1 min, a gas sample, under reduced pressure, was taken. When the sample was gas-free, the crucible

Jan 1, 1969

By AIME AIME

WHEN I was getting data for my books on ore dressing, I traveled across the continent, visiting a great many mills, always accompanied by my vanning shovel, and I got to be a joke among the millmen. They would say "Here comes the Professor with his vanning shovel." With the aid of this vanning shovel, I examined the tailings of all the mills I visited and I found it to be universally true that they contained some extremely fine, free mineral. I looked everywhere to see if I could find a machine or a process that would save this fine mineral. But nowhere did I find anything that made any bid for success until I visited the Kennedy mill, with its Gates canvas plant, on the Mother Lode of California. There I found that the tailings of the Frue vanners were put into a one-spigot classifier of good design which yielded a spigot product entirely free from this fine, free mineral which only assayed 40c. to the ton in gold. The overflow was extremely fine and as¬sayed $3 to the ton. This overflow was fed to ten canvas tables each 10 ft. square, with the grain of the canvas running across the table to make for the roughest surface. The canvas used was No. 6 cotton duck sail cloth.

Jan 1, 1934

By J. Nutting, D. H. Kirkwood

The oxidation of lead sulfide in air between 200° and 350°C has been investigated by electron diffraction from thick sulfide films and from galena surfnces. It has been demonstrated that sulfate is the stable reaction product up to 570°C. Sulfate is HAGIHARA has investigated' single crystals of galena roasted in air by the reflection electron-diffraction technique, which owing to the very limited penetration of the beam into the crystal gives information of the nature of the surface only. He has shown that up to 280°C the first oxidation product is lead sulfate, followed by lead mono-oxysulfate (PbO . PbS04). At longer times and higher temperatures more complex patterns appeared which could not be analyzed. All of these patterns were of streaks or spots arising from crystals oriented on the galena surface, and it is probable that these crystals are lead compounds whose structures have not been determined, such as the other oxysulfates (2Pb0 • PbS04 and 4Pb0 . PbS04) or a number of oxides. Certain lead sulfide films, formed chemically, give ring patterns in transmission electron diffraction2 because they are polycrystalline, and should also give ring patterns of the products after oxidation. It was thought that a diffraction study would reveal the sequence of phases produced in the reactions at different temperatures, since X-ray powder patterns are available for many lead compounds. PREPARATION OF FILMS The films were prepared by passing H2S over a saturated solution of lead nitrate in water. Once a silvery film had formed on the solution surface, no further thickening was apparent. The films were transferred by a gauze to a bath of distilled water for washing and pieces of film were caught on small discs on which they were dried. The discs were formed initially on galena up to temperatures of 300°C, followed by oxide and oxysulfates in turn at longer times. The appearance of- these phases is believed to result from an inadequate rate of supply of sulfur to the top surface 01. the crystal. standard Siemens mounts, made of platinum alloy, and had seven 20-p apertures drilled through them. The parts of the film which had dried onto the disc surface were light blue in color, which is the interference color of a film about 600A in thickness. A strong pattern of lead sulfide was obtained in transmission electron diffraction through the apertures but slight broadening indicated a crystallite size of around 200A. Tilting a sulfide film in the beam produced arcing of the rings, increasing the intensities of the (Ill), (3111, and (222) rings and reducing (200) and (220). This arises from preferred orientation in the film, a [loo] direction of the crystallites being normal to the plane of the film. These specimens were oxidized in an oven maintained at the required temperature. The reported times include that taken to heat the film to the reaction temperature. STABLE PHASES FORMED IN OXIDATION The conditions in which various oxidation products of lead sulfide are stable have been considered by the authors in a previous paper.3 It was shown that in a normal atmosphere, taken as containing lo-' atm of SOs, lead sulfate would be stable up lo about 570°C. This was confirmed by oxidizing thin films of sulfide for several days, and the analysis of the transmission-diffraction pattern is given in Table 1. The fit with the patt$rn from X-rays is good, except for the missing 3.62A ring. Some disagreement in intensities of reflections given by X-rays and electrons is to be expected. Up to 570°C a spotty pattern of sulfate was still obtained, indicating grain growth, but above this temperature the film disintegrated. Probably this is associated with the decomposition to PbO . PbS04. It needs to be emphasized that the atmosphere

Jan 1, 1965

By AIME AIME

MORTIMER ELWYN COOLEY, dean of the College of Engineering and Architecture of the University of Michigan, has been elected president of the American Engineering Council of the Federated American Engineering Societies. This was announced at a meeting of the Executive Board of the Council held at the Cosmos Club in Washington on Sept. 30. Dean Cooley assumes office at once. The new head of organized engineering is a past president of the American Society of Mechanical Engineers and has a long record of distinguished service in education, under the government and in private capacities. He was born in Canandaigua, N. Y., March 28, 1855, and was graduated from the United States Naval Academy in 1878. With his classmate, Dr. Ira N. Hollis, he was ordered to the U.S.S. "Quinnebaug," then fitting out at the Norfolk Navy Yard preparatory to a cruise in the Mediterranean.

Jan 1, 1921

By Henry M. Howe

THE death of Sir Lowthian Bell removes almost the last of the group of heroic leaders who made their age and ours the Age of Steel-a group which his luster and the luster of his peers, Bessemer, Siemens and Tunner, made one of the most brilliant, perhaps even the most brilliant, in the annals of industry. Born on February 15th, 1816, in Newcastle-on-Tyne, he was the eldest son of Thomas Bell, an alderman of Newcastle, and of his wife Catherine Lowthian of Newbiggin, near Carlisle, in Cumberland, and was christened Isaac Lowthian, the name of his maternal grandfather. His father was born about 1788, and came in 1808 from Newbiggin to Newcastle, where he entered the office of the Cumbrian firm of Losh and Company, manufacturers of alkali and wrought-iron, at the Walker Iron and Alkali Works, at Walker, Dear Newcastle. Young Isaac Lowthian Bell was educated at Dr. Bruce's school in Newcastle, whence he went to Germany and Denmark, learning there German and Danish. On his return he studied at Edinburgh University, and then at the Sorboune in Paris. As a student he already showed the remarkable character and application which later gained him such distinction. After studying the manufacture of alkali near Marseilles, he returned, and when about twenty years old (A.D. 1836) was employed in his father's firm, then called Losh, Wilson, and Bell. After spending a year in their Newcastle offices, and after visiting the important iron-making districts of France, Germany, Poland, and Austria, he took charge of their rolling-mills at Walker, and profited so well by his opportunities, and especially by the teachings of his father and of Mr. John Vaughan (later one of the founders of the great firm of Bolckow, Vaughan & Co.), that he was made manager of the Walker works in or about

Sep 1, 1905

By Walter Renton, Ingalls

SEVERAL years ago I became interested in computing the historic lead production of the United States, and the mines, or mining districts whence derived. This led me subsequently to an examination of the recent records- of some of the American zinc-mining districts and of the great lead and zinc-mining districts in foreign countries. My present article thus will be to a large extent an addendum to my book, "World Survey of the Zinc Industry," which was published by the Mining and Metallurgical Society of America in 1931, and to which I shall refer hereinafter as Ingalls, op. cit. Throughout this article all expressions of tons mean the ton of 2000 lb. Where original data have been given in metric tons I have converted in many instances simply by multiplying by 1.1, and long tons by 1.12. I have not been fussy about digits and have rounded off many figures. These may explain differences between data herein and other data.

Jan 1, 1946

By C. A. Schempp

STUDY of the adaptability of Tintic Standard ores to concentration dates back to somewhat before January, 1921, when the chloridizing mill at Harold, Utah, was put into operation. The operation of this mill has been fully covered in the TRANSACTIONS (Vol. 73). The process consisted essentially of a chloridizing roast followed by a percolating leach with a nearly saturated solution of common salt, acidified with sulfuric acid; precipitation of silver on sponge copper, and of copper and lead on tin-plate cuttings. This mill was built to treat the low grade siliceous ores having an average content of

Jan 1, 1933

By Eugene N. Cameron

Graphite is the hexagonal form of crystal-line carbon. It is found in nature locally as tabular crystals but occurs mostly as disseminated flakes, foliated, platy, or fibrous masses, or microcrystalline compact to earthy material. Graphite is characterized by its gray to black color, metallic luster, black streak, perfect basal cleavage, softness (H = 1-2) and unctuous feel. It is sectile and flexible and has a specific gravity of 2.1 to 2.3. It is an excellent conductor of heat and electricity and is inert to ordinary chemical reagents. It melts at a temperature of about 3500°C and vaporizes at a temperature of about 4500°C. In the presence of oxygen it oxidizes to CO2 in the temperature range 600° to 700°C, but it is stable at ordinary temperature and markedly resistant to chemical weathering. Although some natural graphite is nearly 100 pct pure carbon, most contains mechanical impurities of various kinds; quartz, biotite, muscovite, pyrite, iron oxides, and feldspars are the most common. Commercial graphite products have a wide range of graphite content, but the better grades contain 80 pct graphite or more. Both natural and manufactured (artificial) graphite are used in industry. Natural graphite products are divided into two broad categories based on grain size. Graphite composed of visible crystals is called "crystalline" graphite, whereas graphite so fine-grained that it is not visibly crystalline is termed "amorphous." The distinction is arbitrary, for all natural graphite is crystalline, and all gradations between the two commercial categories are known. Within the two categories the terminology used in industry is confusing and not entirely consistent. Crystalline graphite comes from two principal types of sources. The first consists of rocks containing disseminated flakes of graphite. This source yields the "flake graphite" of industry. The second comprises vein deposits of graphite, of which those in Ceylon are the most important and furnish the Ceylon graphite of industry. Amorphous graphite comes from any of a variety of sources, including some of those that yield crystalline graphite. Manufactured graphite is made by electric furnace processes, mostly from petroleum coke. Occurrence and Distribution of Graphite Deposits GENERAL Graphite is widely distributed in nature, occurring in igneous, sedimentary, and metamorphic rocks, and even in nickel-iron meteorites. Graphite deposits of economic interest, however, occur mostly in metamorphic terranes. Five principal geologic types of deposits are recognized: 1. Deposits consisting of flake graphite disseminated in metamorphosed siliceous sediments. 2. Deposits consisting of flake graphite disseminated in marbles. 3. Deposits formed by thermal or dynamothermal metamorphism of coal or other highly carbonaceous sediments. 4. Vein deposits of the Ceylon type. 5. Contact metasomatic or hydrothermal deposits in marble. DEPOSITS IN METAMORPHOSED SILICEOUS SEDIMENTS Deposits consisting of flake graphite disseminated in metamorphosed siliceous sedi-

Jan 1, 1960

By J. L. Bray

ACCELERATED programs, as discussed in this paper, refer to the year-around operation of a college or university with three sixteen-week or four twelve-week terms per year, with pauses between sufficient only to allow the administrative group to perform their functions. In most engineering schools, under such conditions, the conventional four-year course can be condensed to two years and eight months. These accelerated programs of study, which now exist in most of our technical institutions, were forced upon us under the influence of the outburst of wartime patriotism, perhaps one might go so far as to call it hysteria. Many of us felt and hoped that these programs were temporary expedients, but the cold hard threat of permanency now rears its head; consequently we should examine the merits and shortcomings of the new order, and evaluate its effect on our educational system, since it may persist in some form in the postwar years, because of the changing political and financial situation. Many engineering students are being educated in state supported institutions

Jan 1, 1944

By H. S. Price, R. L. Reed, J. E. Warren

The behavior of the reverse-combustion process in a linear adiabatic system is theoretically investigated by means of an idealized physical model. T his model is described by a pair of non-linear equations involving heat and mass transfer which are coupled by a concentration-dependent reaction-rate function of the Ar-rhenius type. The differential equations governing the quasi steady-state temperature and concentration distributions are approximately solved by using either physical or mathematical simplifications. It is shown that the reverse -combustion process can be mechanistically described by simple physical models whose behavior equations can be solved formally. It is further demonstrated that the derived reverse-combustion equations can be solved numerically within the error limits for the experimental data. The theoretically predicted peak temperature-flux-velocity relationship exhibits reasonable agreement with experimental data obtained from Athabasca tar sand. The principal contribution of this work lies in its usefulness as a starting point for developing a more comprehensive theory. A description of the vaporization-coking process must be obtained; then, the theory must be extended to three dimensions to include geometrical effects and heat losses. INTRODUCTION In another paper,'" he physical processes visualized as occurring during reverse combustion have been described. In this paper, the extent to which an elementary theory can account for experimental observations is determined. Theoretical results that can be used to estimate some of the behavior characteristics of importance to this process are also presented. Since it is not possible to include all the features of the combustion mechanism of which we are currently aware, the mathematical formulation refers to the highly idealized system developed herein. This simplified physical model is based on the simultaneous transfer of mass and heat accompanied by a chemical reaction: it is described mathematically by a pair of coupled, nonlinear differential equations. Similar sets of equations have been studied extensively in the field of flame propagation; an excellent review of these investigations has been published by Evans.1 FORMULATION OF THE PROBLEM It will be recalled that the experiments are performed with a thin-walled cylindrical tube that is uniformly packed with sand and oil. The system is maintained substantially adiabatic by means of heat supplied externally in such a way that the radial temperature gradient in any plane normal to the axis of the tube approaches zero. Initially, the tube is at ambient temperature, except at one end where it is rapidly heated to a predetermined temperature. When the prescribed temperature is achieved, air is caused to flow into the cold end of the tube. As the oxygen in the air stream contacts the hot oil, a localized exothermic reaction takes place. The generated heat is conducted and convected away from the reaction zone so that definite temperature and concentration profiles are rapidly established and move uniformly in a direction opposite to that of the air flow (Fig. 1). As a consequence of this mode of oxidation, all of the oxygen in the air is consumed; then, the remaining nitrogen and the gaseous combustion products sweep out all vaporized hydrocarbons and leave an immobile hydrocarbon-coke on the sand.

By L. W. Blau

THE entrance of geophysics and geochemistry into petroleum engineering may be viewed with apprehension by some engineers. They may not remember the time when "practical oil men" opposed the invasion of engineers into the field of petroleum production. By their excellent contributions they established themselves. In the popular mind, engis veers are practical men whereas physicists and chemists are suspected of being theoretical. It will be best to annihilate this misconception right now at the beginning of a closer relationship between petroleum engineers. geophysicists, and geochemists.

Jan 1, 1943

By W. N. Lacey, R. H. Olds, B. H. Sage

The volumetric behavior of five mixtures of black oil and natural gas and of two mixtures of condensate and natural gas from a field in the San Joaquin Valley was experimentally established. This work was carried out at roo°, I9o° and 250°F in the pressure interval between 400 and 5000 psi. The viscosity of the liquid phase of four mixtures of black oil and natural gas was experimentally measured in the above-indicated temperature and pressure intervals. The effect of methane upon the precipitation of bitumen from the black oil was studied at 230°F. Introduction The solution of a number of the economical and technological problems which arise in connection with petroleum production is dependent upon the availability of the necessary quantitative information covering the materials involved. This requires data concerning physical properties of naturally occurring hydrocarbon mixtures at the pressures and temperatures characteristic of underground petroleum reservoirs. The experimental determination of the desired data for each situation encountered is relatively time-consuming. However, it is considered to yield results sufficiently more reliable than those obtained from correlations to justify the effort. For these reasons there was undertaken a laboratory investigation of the viscosity of the liquid phase and the volu- metric and phase behavior of mixtures of oil and gas samples obtained from wells in a field located in the San Joaquin Valley. Terminology The nomenclature of petroleum engineering is not at present entirely standardized. Many commonly used technical terms are not everywhere given the same meanings. For the purposes of this paper the following definitions will be adopted: Black oil refers to the dark-colored, hydrocarbon liquid obtained when the producing horizon of the well lies partly in the condensed hydrocarbon phase of the reservoir. Condensate is the term applied to the relatively volatile, pale yellow or amber-colored hydrocarbon liquid that is often obtained from the surface separator system when the producing horizon of the well lies in the gas cap of the reservoir. The gas obtained from the surface separator system is called natural gas regardless of whether the well is producing black oil or condensate. As might be expected from the multi-component character of naturally occurring hydrocarbon materials, the compositions of black oil, condensate and natural gas are subject to considerable variation depending upon the temperatures and pressures prevailing in the surface separator system as well as upon the overall composition of the material produced from the reservoir. In order to obtain samples capable of reproducing the total hydrocarbon material produced by the well, all oil and gas mixtures used in this investigation were com-

Jan 1, 1949

Raymond Weir Smyth, born Nov. 3, 1888, was the son of Herbert Weir Smyth, professor of Greek Literature at Harvard University. He graduated (A. B.) from Harvard in 1909 and later pursued advanced studies there in chemistry and in metallurgy. He held the position of metallurgist for the American Steel and Wire Co. at Worcester, Mass., and also for the Steel and Tube Co. at Youngstomn, Ohio. For a time he was inspector of munitions for the British Government and stationed at the Railway Steel and Spring Co. at Latrobe, Pa. For a short time, in 1917, he was Inspector of Ordnance for the U. S. Government, and the following year, having entered the U. S. Naval Reserve Force, he was ordered in a similar capacity to the Midvale Steel Co. In September, he removed to the Navy Yard, League Island, Philadelphia, to train for the obligatory minimum of six months' sea duty. There he contracted influenza, which was followed by pneumonia, from which he died, September 27, at the Navy Yard Hospital. Captain Braxton Bigelow* Captain Braxton Bigelow was the son of Major John B. Bigelow, U. S. A., retired, and grandson of the late John Bigelow, author, and Minister to France under President Grant. Captain Bigelow graduated

Jan 1, 1920

By Max W. Ball

Our ever-increasing use of minerals has been the outstanding fact in our American economic development. The rise in our standard of living in the past century is without equal in human history. Nowhere in time or place has the man who works lived so well, or the man who cannot work been so well cared for. We live in a new world, even the poorest of us, that our forebears of 1849 could not have dreamed. That new world has come mainly from our use of minerals. Our per capita use of nonmineral products has grown too, but by only a modest amount. Food consumption per person has grown about 15 per cent in the past fifty years; lumber use per person ,has fallen 56 per cent and that of wood for fuel 65 per cent. Of all the products of field and forest, our use, per capita, may have increased by one fifth during the present century. In contrast, our per capita use of minerals has multiplied several times. Each of us uses 2% times as much steel and 16% times as much petroleum as our fathers used in 1900. In less than half a century our per capita consumption of all minerals has probably risen by 200 to 250 'per cent. Man once built with wood; today he builds mainly with brick and stone and steel. Once he traveled by the power of hay and oats; today he travels by the power of coal and oil. Rubber made from minerals is already better for some uses than rubber tapped from trees; before long it will be better for most and perhaps all uses. Even our ladies' graceful legs are clad in mineral fiber, where once animal or vegetable fiber would have covered them. Our high standard of living is a product of the machine.. The machine is made of minerals. The machine is driven by minerals. The machine age is a mineral age.

Jan 1, 1949

By F. W. Schremp, V. L. Johnson

This paper discusses the results obtained from high temperature, high pressure filter loss studies in which field samples of clay-water, emulsion, and oil base fluids were used. High temperature, high pressure tests of some premium priced emrilsion and oil base drilling fluids show filter loss peculiarities that are not predicted by standard API tests. It is recommended that high temperature, high pressure filter loss tests be used to evaluate the performance of such fluids. Apparatus is described which proved to be satisfactory for evaluating filter loss behavior over a wide range of temperatures and pressures. INTRODUCTION The petroleum industry spends large sums of money each year on chemical treating agents for lowering filter loss and on premium-priced low filter loss drilling fluids. While it is an accepted fact that low filter loss is advantageous during drilling operations, it is questionable whether the present standard method of determining filter loss gives a reliable indication of the loss to he expected under bottom hole conditions. The purpose of this paper is to show that high temperature. high pressure filter loss tests Should be used to evaluate filter loss behavior of fluids for deep drilling. Concern over possible effects of filter loss on oil well drilling and well productivity dates back to the early 1920's. During the years 1922 to 1924, filtration studies were reported by Knapp,' Anderson2 and Kirwan." These studies were the first to be reported in the literature on this subject. No further information was published on the subject until 1932 when Rubel' presented a paper in which he discussed the effect of drilling fluids on oil well productivity. In 1935. .Jones and Babson constructed the first laboratory tester designed to study the effects of temperature and pressure on the filter loss behavior of clay-water drilling fluids. In a discussion of their investigations, Jones and Babsons stated, "Performance characteristics of a mud can he evaluated with considerable reliability by a single test at 2,000 psi and 200°F. Exact correlation between the results of performance test5 made under these conditions and the behavior of muds in actual drilling operations is of course impossible." Jones arid Babson apparently were well aware that at best laboratory tests can give only qualitative answers to the question of what is the actual behavior of a drilling fluid when subjected to deep drilling conditions. Jones' presented a paper in 1937 in which he described a static filter loss tester to be used for routine filter loss tests. This instrument subsequently was adopted as the standard APl filter loss tester. In 1938, Larsen7 developed a relationship between filtrate volume and filtrate time that is in general acceptance today. Larsen was cognizant of the danger of estimating bottom hole behavior from filter loss measurements at room temperature. He tried to predict the effect of temperature on filter loss by relating temperature effects through the temperature dependence of filtrate viscosity. This was undoubtedly an over-sirriplification of the temperature dependence of drilling fluid filter loss. In 1940, Byck" published a summary of experimental results of filter loss tests made on six representative California clsy-water drilling fluids. He concluded that "no existing method will permit even an approximate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the temperature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied." Byck's findings were presuma1)ly well accepted and recognized by drilling Fluid technologists, and yet, they did not lead to wide adoption of high temperature drilling fluid filtration equipment. This is evidenced by the fact that no addition information has appeared in print on the subject since 194). Study of Byck's data shows that there was a useful consistency in them. The fluids did not show predictable losses at high temperatures, but they did line up at high temperatures in approximately the same order that they lined up at low temperatures. That is, if a fluid appeared to be a good fluid with relatively low loss at low temperatures, it would also be a good fluid with relatively low loss at high temperatures. In the last decade. the above situation has changed. The drilling fluid art is markedly different from what it was. The outstanding change, as far as the present discussion is concerned, has been the adoption of wholly new types of drilling fluids. Oil base and emulsion drilling fluids have come in to wide use. It is, therefore, necessary- to re-examine previously satisfactory generalizations to see if they are still valid. It turns out. as might have been expected. that Byck's explicit generalization. already quoted, is still true. Filter losses at high temperatures cannot be predicted from filter losses at low temperatures. However, no further generalizations are valid now. Fluids of different chemical types show different general behaviors. No longer do the fluids line up approximately the same at high temperatures as they do at low temperatures. They may line up entirely differently. Special fluids exhibiting very low loss at low temperatures may have losses as high as those of ordinary clay-water fluids at high temperatures. This fact is highly significant, because premium prices are being paid for the special fluids.

Jan 1, 1952

By Daniel Hanson

FoR most of their practical applications metals are required to withstand stresses of appreciable magnitude: indeed, it id because they possess the quality of resisting stress without becoming permanently deformed that they find such extensive use in the service of man. Metals and alloys must, in service, usually behave as elastic substances—or nearly so. It is not difficult to satisfy this condition at ordinary temperatures. Iron and its alloys, especially the steels, are at normal temperatures excellent elastic bodies, capable of satisfying most of the mechanical requirements of the engineer: where electrical, chemical or other properties are impor-tant, which cannot be met by steels, it is usually possible to find a non-ferrous alloy such as nickel, copper or aluminum, which will prove satisfactory. When the metals or alloys are not inherently sufficiently elastic, cold-working or heat-treatment may develop elastic properties to a sufficient extent for practical needs. By means of relatively simple, rapid tests we can measure such properties as elastic modulus, limit of proportionality and proof stress, upon which design can be based with confidence. The case of the soft metals, such as lead and tin, is well known to be exceptional. They possess no definite limit of elasticity, and the value of proof stress or tensile strength depends to a great extent on the speed with which the test is carried out. Design here must be based on other considerations than a well-established theory of the proportionality of stress and strain. It is now generally recognized that steels and non-ferrous alloys possess at temperatures not greatly exceeding that of the atmosphere, characteristics quite different from those existing at ordinary temperatures, and that they assume qualities similar to those of the soft metals. Not only have they no limit of elasticity, but the proof stress and the ultimate stress depend on the time of application of the load. Flow under load may persist for long periods of time, possibly indefinitely, and the determination of a true maximum stress becomes a matter of great difficulty.

Jan 1, 1939

By Daniel Hanson

FoR most of their practical applications metals are required to withstand stresses of appreciable magnitude: indeed, it id because they possess the quality of resisting stress without becoming permanently deformed that they find such extensive use in the service of man. Metals and alloys must, in service, usually behave as elastic substances—or nearly so. It is not difficult to satisfy this condition at ordinary temperatures. Iron and its alloys, especially the steels, are at normal temperatures excellent elastic bodies, capable of satisfying most of the mechanical requirements of the engineer: where electrical, chemical or other properties are impor-tant, which cannot be met by steels, it is usually possible to find a non-ferrous alloy such as nickel, copper or aluminum, which will prove satisfactory. When the metals or alloys are not inherently sufficiently elastic, cold-working or heat-treatment may develop elastic properties to a sufficient extent for practical needs. By means of relatively simple, rapid tests we can measure such properties as elastic modulus, limit of proportionality and proof stress, upon which design can be based with confidence. The case of the soft metals, such as lead and tin, is well known to be exceptional. They possess no definite limit of elasticity, and the value of proof stress or tensile strength depends to a great extent on the speed with which the test is carried out. Design here must be based on other considerations than a well-established theory of the proportionality of stress and strain. It is now generally recognized that steels and non-ferrous alloys possess at temperatures not greatly exceeding that of the atmosphere, characteristics quite different from those existing at ordinary temperatures, and that they assume qualities similar to those of the soft metals. Not only have they no limit of elasticity, but the proof stress and the ultimate stress depend on the time of application of the load. Flow under load may persist for long periods of time, possibly indefinitely, and the determination of a true maximum stress becomes a matter of great difficulty.

Jan 1, 1939