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By P. A. Albert

THE to a transformation has been investigated by Newkirk1 in sponge titanium alloys which had been relatively slow-cooled so that several grains formed in a former grain. For a nucleated from , Newkirk assumed the following relationships and found them consistent with his experimental results: (00.1)a (110)Pll.01. II [111] Liu and Margolin,' in their investigation, found that the habit planes of martensitic in titanium consisted of planes of the families (3341, and (3441,. Using Newkirk's orientation relationship, the (3341 habit plane is found to correspond to the (1450) plane of a.

Jan 1, 1954

By Guy R. Johnson

In view of the attention now directed to the development of the iron-ores of Virginia, and of the frequent reference in the Transactions of the Institute to the Longdale mines, it is presumed that a brief account of the methods of working and surveying these mines will be of interest. For a better understanding of such a description, a few words will be said concerning the geological character of the ore-deposit. Professor Rogers says in his preliminary report of 1835, that this deposit has " more of the character of a true vein than is usually

Jan 1, 1892

By J. W. Fuller

DURING the last 20 years, experimenters have sought to utilize pulverized coal in boiler plants, but refractory and slag troubles have usually overbalanced any, gains in efficiency that were obtained. These troubles were caused largely by lack of knowledge of the proper methods of coal preparation and lack of a furnace design that would be adaptable to pulverized-coal firing. When this information was obtained the results were so much more satisfactory that within the last 5 years approximately, 80,000 boiler hp. have been installed in plants ranging from 1000 to 20,000 boiler hp. rated capacity, which are operating at an average of 174 per cent. of rating. The first commercial installation for burning pulverized coal under boilers was made at the Parsons shops of the M. K. & T. railroad in 1916. Of eight 250-hp. water-tube boilers thus fitted, six were operated continuously for 3 yr., when oil was obtained at such a low price as to warrant its use. Since then, this plant has been operating alternately on pulverized coal and oil, depending on prevailing prices. Recently gas has been discovered within 20 mi. of this plant, so that this fuel may also be used. No change in furnace design was made when changing from pulverized coal to oil or gas firing. One of the principal advantages of this method of firing is its ability to utilize, with maximum efficiency, all kinds of coal, irrespective of quality or physical characteristics. In fact, quite a number of the present pulverized-coal installations were made for the purpose of utilizing coal that could not be marketed or used in any other way. The Pacific, Coast Coal Co., at Black Diamond, Wash., formerly hand fired the boilers, using approximately 125 tons of prepared steam-size coal daily. The Black Diamond steam coal is the best quality of coal for steaming purposes mined in that section of the country, and there is a market for all that can be produced. By installing a pulverizing plant, it was possible to substitute coal of a size and quality that had no commercial value, so that 125 tons daily of the best steam coal formerly used at the mines is now marketed.

Jan 12, 1921

By F. W. Bloecher, A. M. Gaudin

THIS paper describes the results of a series of tests carried out to determine the partition of dodecylamine between distilled water and the surface of quartz at various concentrations of dodecylamine acetate in solution. An adsorption-column technique was utilized for this purpose. Ralston and Harwood, of Armour and Co., had synthesized marked dodecylamine acetate for us.' In their preparation which we employed, 0.0007 pct of the total carbon was the radioactive isotope, carbon fourteen. Unmarked dodecylamine acetate of high purity was also prepared by them for our use. The presence of carbon fourteen in the dodecylamine enabled us to analyze quantitatively for dodecylamine on the surface of quartz, using a radioactive-tracer technique. The method used was that known as internal gas counting of carbon dioxide, formed by oxidation of the amine. This method has already been described, "3 ' and the reader is referred to these papers for details of the analytical method and procedures. and surrounding liquor, a technique analogous to chromatographic columns was utilized. The experimental setup is shown in fig. 1. The dodecylamine-acetate solution was made up in a volumetric flask and poured into the glass funnel shown. It was allowed to drip slowly onto the quartz bed, the rate of flow from the funnel reser- voir being controlled by a hose clamp. The quartz column was contained in a small, fritted-glass filter (size 20 mm, C). The beaded top edge of the filter was cut off to enable the holder and contents to fit into the open end of the 30/45 joint on the combustion tube. This combustion tube is used in the analytical train described in a previous paper.' A piece of gum-rubber tubing joins the bottom of the fritted-glass filter to a filter flask, which in turn is connected to a vacuum line, or water aspirator. The rate of flow of amine solution through the bed was

Jan 1, 1951

By Kendall E. Born

Production of crude oil in Tennessee during 1936 approximated 20,000 bbl., about the same as in 1935. Accurate figures are available only for the Glenmary field in southwestern Scott County and the Boone Camp, Seabolt, and Coon Hollow pools in north central Morgan County. Small amounts of oil were produced in the Poplar Cove region of eastern Fentress County, in Tinsleys Bottom along the line between Clay and Jackson Counties, and in the Lock Branch pool of northern Jackson County. The renewed interest in these three pools, which were abandoned for several years, reflects the effect of rising prices for crude oil in Tennessee. Developments in these fields were begun late in 1936 and therefore have had little cffect on the production for the year. A nurnber of small scattered wells in abandoned fields in Clay County were pumped intermittently during the year, but no production figures are available on this production. The acidizing of a number of wells in Scott and Morgan counties reported last1 year has been responsible for an increase of nearly 4000 bbl. over 1935 in this region. Results have shown, however, that the Glenmary pay (Glenmary and Coon Hollow pools) at about the top of the St. Louis limestone, responds more favorably to acid treatment than does the Boone Camp (Boone Camp and Seabolt pools) horizon in the Fort Payne formation of lower Mississippian age. This difference is probably due to the siliceous and argillaceous content of the Boone Camp pay. The only natural gas marketed off the lease in Tennessee during 1936 was in Morgan County, where approximately 10,000,000 cu. ft. were furnished the towns of Sunbright and Burrville and the immediate vicinity. The gas occurs with the oil in the Boone Camp field and small amounts were put on the line from the near-by Coon Hollow and Seabolt pools. There are 11 gas wells in the area. Development Although the presence of petroleum in Tennessee was noted more than one hundred years ago, this state has never been an important

Jan 1, 1937

By F. W. Bloecher, A. M. Gaudin

THIS paper describes the results of a series of tests carried out to determine the partition of dodecylamine between distilled water and the surface of quartz at various concentrations of dodecylamine acetate in solution. An adsorption-column technique was utilized for this purpose. Ralston and Harwood, of Armour and Co., had synthesized marked dodecylamine acetate for us.' In their preparation which we employed, 0.0007 pct of the total carbon was the radioactive isotope, carbon fourteen. Unmarked dodecylamine acetate of high purity was also prepared by them for our use. The presence of carbon fourteen in the dodecylamine enabled us to analyze quantitatively for dodecylamine on the surface of quartz, using a radioactive-tracer technique. The method used was that known as internal gas counting of carbon dioxide, formed by oxidation of the amine. This method has already been described, "3 ' and the reader is referred to these papers for details of the analytical method and procedures. and surrounding liquor, a technique analogous to chromatographic columns was utilized. The experimental setup is shown in fig. 1. The dodecylamine-acetate solution was made up in a volumetric flask and poured into the glass funnel shown. It was allowed to drip slowly onto the quartz bed, the rate of flow from the funnel reser- voir being controlled by a hose clamp. The quartz column was contained in a small, fritted-glass filter (size 20 mm, C). The beaded top edge of the filter was cut off to enable the holder and contents to fit into the open end of the 30/45 joint on the combustion tube. This combustion tube is used in the analytical train described in a previous paper.' A piece of gum-rubber tubing joins the bottom of the fritted-glass filter to a filter flask, which in turn is connected to a vacuum line, or water aspirator. The rate of flow of amine solution through the bed was

Jan 1, 1951

By M. S. Enders, L. M. Rogers

The Little Rocky Mountains host epithermal gold-silver bearing vein and stockwork deposits in a syenite intrusive complex. Pegasus Gold Ltd. is currently mining these oxidized deposits by open-pit methods and recovering gold and silver by heap-leach processes. A geologic program has been designed to effectively determine the basic ore characteristics; 1) mineralization; 2) oxidation; 3) structural setting; 4) lithology; 5) alteration; and ultimately, 6) the leachability of the ore. Geologic mapping, sampling, drilling, assaying, and testing are routinely used in exploration, development, production control, mine planning, and ore reserve estimations. Timely and accurate assay results are essential for the program's success.

Jan 1, 1984

By W. N. Best

THIS paper is not intended as a scientific discussion of the combustion of oil but is written from, the standpoint of an operator who has the experience and qualifications necessary to guide others in producing the most economic results in the use of liquid fuels. Oil, in this paper, usually, means petroleum or its products but incidental reference is made to other liquid and gaseous fuels, so that the term may be considered, as referring to all liquid and gaseous hydrocarbons in comparison with solid fuels, as coal and. wood. However, only a few of the principal factors in the use of oil as a fuel can be given. The present, and prospective, high price of coal is causing users of fuel to renew inquiry as to the merits of other forms of fuel for industrial purposes. Crude oil (petroleum) is proving to be one of the world's most valuable mineral resources. The recent discovery that oil underlies a considerable area of the United States, Mexico, and other parts of the world to a greater extent than was formerly believed and the large production of some of the wells in these areas shows the probable quantity of fuel oil that may now be available. Through the energy of Lord Cowdrey, who was one of the pioneers of the oil industry in Mexico, oil has been discovered in England; some prominent geologists believe that it may be found yet, in quantity, in Great Britain. For years, oil has been known to be of great value in the manufacture of metals. It has proved incomparable in forge shops, steel foundries, heat-treating furnace s, and wherever accuracy of temperatures is essential, or where a maximum output is desired as well as quality of metal. In some types of equipment, the output produced with oil as fuel is double that obtained with coal and, at a reduction of 50 per cent, in the cost of the fuel. For example, in drop-forging plants, the metal is always waiting for the man when oil is used as fuel, whereas with coal, the man must wait for the metal to become sufficiently heated.

Jan 8, 1920

By J. C. M. Li

This exploratory survey was undertaken to repeat some experiments- in which anomalous results were reported1 for bismuth and to measure the thermoelectric power of some bismuth alloys and inter-metallic compounds. sato1 reported that the thermoelectric power of bismuth depends on the temperature gradient. This seems rather unreasonable especially when the Benedicks effect' has not been detected. Even if the material is not homogeneous, the observed thermoelectric power can be represented by

Jan 1, 1959

By Irvin Lavine

THE discovery of several large deposits of natural sodium sulfate (Glauber salt) in the northwestern part of North Dakota during the summer of 1934 might have been anticipated from a knowledge of the topography and geology of this territory and from the presence of natural C A N A D A FIG. 1.-LOCATIONS OF GLAUBER SALT DEPOSITS, NORTHWESTERN NORTH DAKOTA. North Lake (deposit No. 7) is not shown on this map. It is approximately 13 miles north of Miller Lake (deposit No. 3). sodium sulfate deposits in western Canada, which have been known for several years. In the northwestern part of North Dakota is a chain of shallow lakes, which continues northward into Saskatchewan. Over twenty million tons of Glauber salt has been proved present in these North Dakota deposits. (See Fig. 1.)

Jan 1, 1936

By Herbert Clark Hoover, Lou Henry Hoover

MOST illustrious Princes, often have I considered the metallic arts as a whole, as Moderatus Columella2 considered the agricultural arts, just as if I had been considering the whole of the human body ; and when I had perceived the various parts of the subject, like so many members of the body, I became afraid that I might die before I should understand its full extent, much less before I could immortalise it in writing. This book itself indicates the length and breadth of the subject, and the number and importance of the sciences of which at least some little knowledge is necessary to miners. Indeed, the subject of mining is a very extensive one, and one very difficult to explain ; no part of it is fully dealt with by the Greek and Latin authors whose works survive ; and since the art is one of the most ancient, the most necessary and the most profitable to mankind, I considered that I ought not to neglect it. Without doubt, none of the arts is older than agriculture, but that of the metals is not , less ancient ; in fact they are at least equal and coeval, for no mortal man ever tilled a field without implements. In truth, in all the works of agricul- ture, as in the other arts, implements are used which are made from metals, or which could not be made without the use of metals ; for this reason the metals are of the greatest necessity to man. When an art is so poor that it lacks metals, it is not of much importance, for nothing is made without tools. Besides, of all ways whereby great wealth is acquired by good and honest means, none is more advantageous than mining ; for although from fields which are well tilled (not to mention other things) we derive rich yields, yet we obtain richer products from mines ; in fact, one mine is often much more beneficial to us than many fields. For this reason we learn from the history of nearly all ages that very many men have been made rich by the

Jan 1, 1950

By Eli Sani

Investment in the mineral industries-particularly in the mining industry-differs from investment in nonminera1 industries in that the latter have an indeterminate life, assumed to be perpetual, and are not called upon to replace the firm's original investment. In mining ventures, on the other hand, once the ore bodies are depleted the mine has no economic value; the original capital investment must be returned to the investor by the time the ore is exhausted. A mining venture is also characterized by the significant cost and time associated with the exploration phase. A myriad of samples must be taken, geological features investigated, and ore grade assured. In addition, most mining ventures require substantial capital expenditures aggregating several hundred million dollars for a number of years before the project begins producing any revenue. Any theoretical model employed in evaluating a mining venture, as well as similar mineral ventures, must take all these factors into consideration.

Jan 5, 1977

By W. H. HOWARD

Discussion of the paper of W. H. HOWARD, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 92, August, 1914, pp. 2029 to 2046. EDGAR M. DUNN, Anaconda, Mont.-Mr. Howard's contribution to the literature on the Cottrell, method. of electrostatic precipitation of flue dust and fume at Garfield has been read by us with peculiar interest for the reason that we have been experimenting with the same process at Anaconda for the past eight or nine months, with a view to adapting it, under the direction of Dr. Cottrell and the supervision of J. 0. Elton. and D. R. Kellogg, representing the Anaconda Smelter Commission, to the treatment of very large volumes of gases, using large pipe treaters and various forms of electrodes, with about 150,000 volts rectified current. For the amount of gas to be treated here the 5-in. pipe means a cost for installation that is practically prohibitive, clue to the tremendous number of pipes required, and we have been trying to cut installation costs by increasing the size of the pipes. All of our work is still in the experimental stage, but we have obtained good clearance on our mixed roaster and converter gases with a 3-ft. pipe treater 20 ft. long, and with 5 ft. velocity therein; and with a discharge electrode of a single No. 29 nichrome wire set in the middle of the 3-ft. pipe, with. a consequent electrode spacing of 18 in. The current used has been 150,000 to -160,000 volts, .and of course there have been troubles galore, relating particularly to insulation and rectifying. Blast-furnace gases did not give so good clearance, probably due to relative poverty in moisture and S03 content of blast gases to roaster-converter gases; making the blast gases the poorer in conductivity. Our experience has been so satisfactory that in our next experimental plant-built on a somewhat larger scale-we shall attempt a 4-ft. treater with greater electrode spacing, and a somewhat higher voltage-up to 220,000. As to fractional precipitation, mentioned by Mr. Howard, this idea was tried out at Anaconda last year (1913). Formerly our furnaces (Bruntons) roasting flue dust for the recovery of white arsenic, passed so great an, amount of dust to the settling kitchens that refining of this arsenical product was necessary to eliminate the 5 to 20 per cent. dust contained therein. Consequently the manufacture of As203 was effected in two stages, with a reverberatory roast of the first .product to obtain the final 99.5 per cent. As203. -

Jan 11, 1914

By John L. Boardman

Because of the attention that has recently been given to the health and safety of miners by various organizations such as the A.I.M.E., The American Congress, Mining Section, National Safety Council, as well as the Bureau of Mines and various state mining departments, your committee on health and safety deemed it best to call attention this year to the mine-accident cause that is by far the most important; namely, injuries due to falls of ground, rock, roof and coal. Each of several members of the committee contributed a brief outline of the importance of this accident cause in his district. While these papers were brief, it would require too much time and space to give them in full, therefore we present an outline of each and summation of all. Report of M. D. Cooper, Hillman Coal and Coke Co. M. D. Cooper, Division superintendent, Hillman Coal and Coke Co., Pittsburgh, Pa., contributed the following: During the period from 1930 to 1939, accidents from falls of roof in bituminous mines average 54.3 per cent of all accidents. In mechanized mining, there is a tendency toward reduction in this class of accidents because the operator of the machine is usually at a distance of 10 to 20 ft. from the face, whereas in hand load- ing the miner is close to the face during most of the shift. No doubt the use of aluminum and light steel beams supported at regular intervals by jacks, a common practice in mechanical mining, has contributed to the favorable record so far developed. Report of M. H. Fies, De Bardeleben Coal Corporation Milton H. Fies, Vice-President, DeBar-deleben Coal Corporation, Birmingham, Ala., says: With reference to the types of mining, it is suggested that a clear understanding be had as to the character and thickness of the directly overlying strata, with especial consideration to the strength and in some cases an analysis of it. In coal mining, generally speaking, overlying strata higher in silica than others is stronger. In changing from narrow to wide places, the procedure should be experimental, both as to the width and depth of places and as to the nature of the necessary timbering. Since most of the accidents in coal mining particularly are due to falls of roof and coal, this phase of mining should be attacked with vigor There is no substitute for discipline and, in this connection, under present conditions it is important that cooperation by the labor ornanizations- be sought and that a spirit of fairness prevail. Frequent and thorough inspection of all active working places should be made.

Jan 1, 1943

By John L. Boardman

Because of the attention that has recently been given to the health and safety of miners by various organizations such as the A.I.M.E., The American Congress, Mining Section, National Safety Council, as well as the Bureau of Mines and various state mining departments, your committee on health and safety deemed it best to call attention this year to the mine-accident cause that is by far the most important; namely, injuries due to falls of ground, rock, roof and coal. Each of several members of the committee contributed a brief outline of the importance of this accident cause in his district. While these papers were brief, it would require too much time and space to give them in full, therefore we present an outline of each and summation of all. Report of M. D. Cooper, Hillman Coal and Coke Co. M. D. Cooper, Division superintendent, Hillman Coal and Coke Co., Pittsburgh, Pa., contributed the following: During the period from 1930 to 1939, accidents from falls of roof in bituminous mines average 54.3 per cent of all accidents. In mechanized mining, there is a tendency toward reduction in this class of accidents because the operator of the machine is usually at a distance of 10 to 20 ft. from the face, whereas in hand load- ing the miner is close to the face during most of the shift. No doubt the use of aluminum and light steel beams supported at regular intervals by jacks, a common practice in mechanical mining, has contributed to the favorable record so far developed. Report of M. H. Fies, De Bardeleben Coal Corporation Milton H. Fies, Vice-President, DeBar-deleben Coal Corporation, Birmingham, Ala., says: With reference to the types of mining, it is suggested that a clear understanding be had as to the character and thickness of the directly overlying strata, with especial consideration to the strength and in some cases an analysis of it. In coal mining, generally speaking, overlying strata higher in silica than others is stronger. In changing from narrow to wide places, the procedure should be experimental, both as to the width and depth of places and as to the nature of the necessary timbering. Since most of the accidents in coal mining particularly are due to falls of roof and coal, this phase of mining should be attacked with vigor There is no substitute for discipline and, in this connection, under present conditions it is important that cooperation by the labor ornanizations- be sought and that a spirit of fairness prevail. Frequent and thorough inspection of all active working places should be made.

Jan 1, 1943

By Paul A. Beck, A. H. Lutts

IN a previous paper' isothermal softening and X-ray line sharpening data were reported for the annealing at 350°C of single crystals of pure aluminum rolled on the (110) plane in the [112] direction. It was shown that, after rolling to 80 pct reduction in area and careful etching in such a manner as to eliminate extraneous orientations by removing surface material and disturbed areas adjacent to saw cuts, the specimens may be extensively annealed at 350°C without any observable recrys-tallization. At the same temperature, the line broadening caused by cold rolling was found to disappear practically completely after less than 200 sec of annealing. The present work was undertaken in order to study the temperature dependence of line sharpening and of the initial softening with high purity

Jan 1, 1957

By J. H. Brophy, A. I. Prill

The authors have previously investigated the solid-state activated sintering of tungsten powder with various Ni-Cu additions.' Log shrinkage vs log time plots showed changes in slope from 4 to x at intermediate times during the sintering process. This was attributed to a change in the rate-controlling mass-transport process from solution of tungsten into the tungsten-alloy interface to diffusion of tungsten in this interface. It was postulated that the melting of the activating layer should not affect this transport process. However, the superposition of rearrangement due to the presence of a liquid phase complicates the data analysis. It is the purpose of this note to apply the analysis of Prill, Hayden, and rohy' to account for "rearrangement shrinkage'? in liquid-phase sintering of the W-Ni-Cu system. This results in "solution-precipitation stage" shrinkage plots which were comparable to those obtained in solid-phase activated sintering of the same system. If one assumes total shrinkage to be the sum of rearrangement and solution precipitation, the effects can be isolated easily.2 This results in the general equation:

Jan 1, 1967

By Joseph L. Gillson

YOUR speaker has long sought an opportunity to review the many differences between the subject matter called economic geology and the duties of a practicing economic geologist. As the subject was taught in my student days, professors teaching courses in economic geology paid little attention to what we now call industrial minerals. Certainly they were not concerned with problems involving production and marketing, but only with the origin of such mineral deposits as the Stassfurt potash deposits; with other evaporites, such as salt, gypsum, and Chilean nitrate; with the possible modes of formation of sulfur in salt domes; and the causes of asbestiform mineralization. Of course, much time and thought was given to the mineral identification and sequence of deposition of the minerals in pegmatites. The fact that such deposits actually produced commercial feldspar, mica, beryl, and lithium minerals for sale in industry was of minor importance. These observations lead us to pause to inquire, perhaps facetiously, what is and what is not to be included in the science of economic geology?

Jan 5, 1957

By G. L. Craig

In order to meet the unprecedented demand for copper it has proven necessary not only to develop every primary source, but also thoroughly to exploit the vast reservoir of metal in use that is not directly serving the war effort. To accomplish this, industry has been called upon to use its resourcefulness for developing methods of recovery that have not been previously utilized. It is in this connection that we have been asked to review the methods suggested for recovering the basic constituents of various types of the so-called clad or composite steels. As a background for a discussion of recovery processes, it seems appropriate to consider clad materials in general and their processes of manufacture. A composite steel has been defined as one consisting of two or more component parts of which the smallest shall comprise at least 3 per cent of the total mass. Clad materials or composites are produced commercially by several different methods of which the most important may be classified as: I. The Blacksmith or Forge Weld Method. This method is limited to carbon steels or low-alloy steels as the presence of even small amounts of common alloying metals prevent the formation of a satisfactory weld. The principle is the application of pressure to sections in contact at elevated temperatures. Because of the tendency of the iron to oxidize, borax is generally used as a flux to absorb the iron oxide. 2. Casting Process-In this method a composite ingot, billet or cake is produced by pouring one metal onto or about another. The bond may be accomplished by the action of the molten metal against a solid, in which case the bond may be referred to as mechanical; while in other instances alloying occurs at the interface producing an anchor by the formation of component parts of the two materials. 3. Cementation Process.-In this process any number of combinations of metallic and nonmetallic constituents which are mixed together may be used as a bonding agent. The combinations, whatever they may be, are placed between the materials to be joined and subjected to pressures at elevated temperatures to produce the desired bond. 4. Fusion Welding Processes.-Gas and electric joining for direct use or subsequent fabrication. 5. The, Assembly Process.-This method involves the joining together of prefabricated bars or plates followed by hot and/or cold working the assembly to the desired finished form. This method is advantageous in many cases because of its flexibility on small quantities as compared to the casting method. It is also possible to control the relative proportion of components more accurately. In this discussion we are concerned only with the scrap resulting from the manufacture of clad materials and our interest,

Jan 1, 1943

By Horace W. Hindry

This paper presents the ingredients composing a type of oil-base mud that has been successfully used in drilling oil horizons in California, the effect of ingredient concentrations on physical properties, methods of handling at the well and possible advantages of a waterless drilling fluid with excellent plastering properties. INTRODUCTION AN oil-base mud is a rotary drilling fluid in which oil has been substituted for water as the principal liquid ingredient. In recent years such a mud has been developed and used successfully for drilling the oil horizons of wells in various California fields. There are several types of oil-base mud, but only the type that is currently used to any appreciable extent will be considered at this time. The oil-base drilling-mud compositions used by Shell Oil Company, Incorporated have been covered by several patent applications on which patents are expected to issue at an early date. The purpose of this paper is to present data on the fundamental design of the mud; the ingredients used and their specifications; the effect of ingredient concentration on physical properties; the selection of the proper mud; the facilities needed for handling the mud; and a general discussion [oil] drilling with oil-base mud. In view of the early stage of development of oil-base mud, the great number of variables, and the almost unlimited possible combinations of these variables, which in turn require extensive laboratory study, there are certain irregularities and omissions in the data presented here. However, it is believed that sufficient data are at hand to permit a fairly complete analysis of the characteristics of oil-base muds. In view of the excellent plastering properties of oil-base mud when properly proportioned, its use should: (I) minimize the possibility of impairing the natural flow potentialities of the producing horizon such as that resulting from infiltration of water from water-base muds; (2) permit smaller clearances for setting liners, since the mud sheath has no appreciable thickness; (3) eliminate the possibility of clogging the perforations of the liner with thick mud sheath; (4) facilitate the removal of the mud sheath from the walls of the hole, for its mud sheath has no appreciable strength; (5) assist in drilling through formations, such as "heaving shale," where water wetting appears to be a source of difficulty. (6) permit cores to be obtained without contamination from drilling water. FUNDAMENTAL DESIGN OF AN OIL-BASE MUD In the design of any rotary drilling mud it is necessary to select materials that will fulfill the following requirements: (I) act as the liquid medium and regulate the viscosity; (2) impart initial and final plastering properties; (3) give gel strength and structure in order to prevent settling; (4) serve as a weighting material. The

Jan 1, 1941