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By J. L. Huitt, D. K. Lowe

This laboratory flow study covers propping agent transporl in horizontal fractures as influenced by the characteristics of the propping particles, fluid and fracture. Correlations are presented for the transport of particles, deposition and fingering through dunes. For particles moving individually, the article velocity in some cases may be low compared to the hulk average fluid velocity; in other cases, the particle velocity may exceed the bulk average fluid velocity. At high propping agent concentration or low fluid velocity, the likelihood of particle deposition and dune formation increases. Fingering and channeling accompany dune formation. Dune formation can be limited to the outer region of tile fracture by adjustment of pump rate, fluid viscosity and particle concentration. A method is presented by which pump rate and fluid vircosity may he selected to control dune formation for given propping agent concentrations. INTRODUCTION The area and flow capacity of a fracture predominantly control the stimulation derived from hydraulic fracturing. Generation of fracture area exposes the rock matrix to a flow channel; the flow capacity of the fracture controls the flow through the channel to the wellbore under a given pressure gradient. This paper pertains to an important factor that affects the flow capacity of a fracture: the transport of the propping particles in the fracturing during the hydraulic fracturing treatment. With a better understanding of particle transport, fracturing treatments may be designed to obtain more effective distribution of the propping agent. RELATED STUDIES In recent years, the approach to obtaining high fracture flow capacity has been partial monolayer propping. Three papers1-3 have dealt with various facets of this concept. However, in some papers dealing specifically with particle transport, the results generally indicate that packing the propping particles within a fracture is inevitable. In early work&apos; with a sand slurry flowing in a pie-shaped flow cell, qualitative results showed that particle deposition in a fracture during transport should be expected. In other studies"" correlations based on slurry flow in vertical linear flow cells showed particle deposition was primarily a function of fluid velocity. In a recent paper the rate of sand advance (movement of dunes) in a horizontal linear flow cell was discussed. Subsequently, a method was given for designing fracturing treatments, based on the extent of sand advance during a treatment. In this work, particles whose diameter was small relative to the fracture width (i.e., dl W< 0.2) were primarily considered. The particle transport approaches that of sand transport in a stream bed. The industry trend, however, has been to use larger size propping agents. That is, particles with diameters approaching fracture widths predicted by Perkins and Kern.&apos;&apos; This trend has led to generally better fracturing treatments with particle relative sizes in the range 0.2 <d/W < 1.0. In all of the particle transport studies previously cited, the fluid characteristics were discussed. However, little or no attention was given to the parzicle characteristics. In this study the particles. as well as the fluid and fracture, are considered. VARIABLES AFFECTING PARTICLE TRANSPORT In the exploratory work to set LIP a program for this study, it was noted that particles within a batch moved at different velocities in a horizontal linear flow cell. In some cases the particles moved independently. In others there was particle interference. Also, particle deposition and fluid fingering occurred in some cases (Fig. 1). As a result of observing the easily distinguishab&apos;le types of particle movement, the particle variables as well as the fluid variables were included. In addition, the fracture width was included because the fluid velocity profile surely must affect the movement of the larger particles differently than that of smaller particles. Particle variables were density, diameter (based on a sphere of equal volumetric displacement), long and short dimensions, drag coefficient and velocity. Fluid variables were density, viscosity, yield shear strength and velocity. Fracture variables were the width and the angle between the plane of flow and a horizontal plane. Two factors which may prove to be important were omitted because of the complexity resulting from the parameters cited above. These are the fracture-surface roughness and gross irregularities that cause changes in the direction of flow. EXPERIMENTAL EQUIPMENT AND PROCEDURE A linear parallel-plate flow cell (Fig. 2) was used in the study. Lucite plates 1 in. thick formed the test section and permitted a viewing section 11 ft long and 10 in. wide. Spacing between the plates was adjusted with shims to give fracture widths 1/36 to 1/2 in. The model could be tilted to an angle of 45" with the horizonltal plane. Fluid flow was maintained with a Moyno positive displacement pump. Single particles were placed in the flow stream with a particle injector. A .4 - in. diameter plunger moving at a constant rate in a

Jan 1, 1967

By William M. Sheehan

TRANSPORTATION is one of the most important problems of the mine operator and the possibilities of cost reduction in this field should not be overlooked. In the railroad industry, cars and locomotives have been improved greatly, and the progress there made is well worthy of study by the mine operator looking for maximum efficiency in every branch of his activities. One of the outstanding developments in the construction of railroad equipment in recent years has been the wide-spread adoption of large one-piece steel castings for the framework of locomotives, passenger and freight cars. Some of the advantages and applications of this type of construction will be outlined in this paper, with particular thought of the needs of the mining industry. The inherent qualities of cast steel: homogeneity, unrestricted size and shape, high tensile strength, flexibility of metal distribution, resistance to corrosion, and gracefulness of outline, make it the most versatile member of the ferrous group. Not only is it a strength-giving element, but it is corrosion resistant, a combination that makes for large economies in equipment maintenance. Flexibility of metal distribution allows the integral foundation to be in the shape best suited for the purpose. These cast structures are really assembled in the mold in liquid form and the metal can be placed in the right pro¬portion exactly where it is needed, thus securing weight economy and uniformity of fibre stress. Such a process permits the incorporation, with ease, of necessary brackets, utilizing them to provide not only greater strength for the derail part itself, but often to add to the value of the entire unit. Laps, seams, and joints, which are necessary in all fabricated forms, are eliminated.

Jan 1, 1933

By George S. Rice

ARIAL maps of prospective mineral-bearing territory have become almost indispensable in all the branches of exploration, and have proved particularly useful in the great oil area of the Southwest. About nine years ago aerial photographic mapping in this area was begun. The early product was lacking in scale accuracy and other control features, which limited its effective use. Since then, the evolution of the technique of such mapping has been steady, with several mapping companies collaborating with five of the leading oil companies, and aerial maps have been prepared covering practically the entire area.Improvements in cameras, film, and developing equipment and practice have resulted in more uniform and clearer photographs, but the outstanding development has been the accuracy obtained with respect to scale and all other control features. Maps are no

Jan 1, 1936

By W. F. NETZZEBAND

THE long-hole drill has been used for prospecting underground in the tri-State district for several years, and its value has been pretty thoroughly proved. An attempt was made to get a statement of their experience with the machine from all the operators who were known to have used the machine. The majority of them replied to the questionnaire so that this paper is practically a summary of the experience of the district, together with some practical details taken from the experience of the Eagle-Picher Lead Company. When the drill was first used by the Eagle-Picher Lead Co., it was put in low headings and was mounted on a cross-arm supported by two drill columns. This was found to be a rather awkward method of mounting, because fairly long moves were made and the same drill columns could not be used on any two successive set-ups. The machine was later moved to a mine with high headings so that this type of mounting was found to be impractical. A heavy tripod was tried and found satisfactory, provided care was taken to see that the set-up was solid. The Evans-Wallower Lead Co. and the Century Zinc Co. report using the double post set-up, but the headings are low in these mines. The Commerce Mining St Royalty Co. first used the double-post mounting in high headings by cutting a niche in the wall and setting the post in it. This proved to be a slow and expensive method and was later abandoned for the tripod. The Federal Mining & Smelting Co. has used a tripod throughout its operations. Great care must be taken in using the tripod to see that the set-up is solid. Wherever possible it is advisable to sludge in the legs and let them set a short time before the machine is put into use. Where high bottom is encountered the Eagle-Picher operator found it advisable to drill jack- hammer holes in the bottom and drive the legs into them.

Jan 1, 1930

By Butler, P. B.

TRIPOLI is a rather unusual form of silica, which thus far has been found in commercially valuable quantities only in the neighborhood of Seneca, Mo., although there are numerous deposits of somewhat similar materials in several southern states. The latter have not, however, attained any position of real importance, due undoubtedly to definite structural limitations which have rendered them less suitable for the particular uses that have given tripoli its principal outlets. Raymond B. Ladoo, mineral technologist, says&apos;: "Since that time (1880-90) the term tripoli has with increasing definiteness been reserved for the Seneca material, and other siliceous materials of similar origin and physical properties."

Jan 1, 1928

By E. DeGolyer

USE of geophysical methods as an aid to prospecting for new oil pools and in the exploration of already discovered pools continued to increase and reached a new high during 1934. As in previous years, the scene of greatest activity was the Gulf coastal plain of Texas and Louisiana. Seismic crews working by the reflection method increased from some thirty crews at the first of the year to forty crews at the end. An increased demand for torsion balance work at the beginning of the year occurred and practically all available instruments were put into service. Some thirty crews with approximately eighty balances continued throughout the year. Both the pendulum and gravimeter methods of gravity surveys registered their initial successes and equipment was increased from five to seven pendulums and from one to three gravimeters during the year. Approximately five magnetometer parties continued to work throughout the year. No surface surveys by the electrical method are known to have been made. Outside of coastal Texas and Louisiana the chief geophysical work

Jan 1, 1935

By AIME AIME

THE United Electric Coal Companies, operating large strip mines at various points in Illinois, pioneered in developing and perfecting the strip method of mining coal by use of large shovels and drag-lines. Coal stripping was first started on the properties owned by this company near Danville, Ill., in 1885. The first mechanical&apos; excavating machine used for the purpose was really a dredge minus the hull, which had been purchased from the Marion Steam Shovel Co. It was erected on a wood frame supported by wheels and was referred to as a dry-land dredge or stripping machine. Wood was used throughout in the construction of this primitive excavator, even for the boom which was 50 ft. long. A single-cylinder vertical steam engine furnished power to hoist the %-yd. dipper arid swing the boom. 400 cu. yd. of overburden moved in a day was a great record.

Jan 1, 1936

By J. V. W. REYNDERS

FIRST of all let me express my affectionate gratitude for the cordiality and good will of your reception. On the part of the men I venture to interpret the character of your greeting, not only as a recognition of the position to which you have been good enough to elect me, but also as an expression of your friendly attitude. However, I cannot pass over the tribute of the ladies so casually: Nor does it seem possible to do justice to my sentiments in addressing them collectively. I would feel more equal to the task if I could have the opportunity to talk to them singly, in doing which I know I may count upon their good sportsmanship not to compare notes. There has been some discussion between Mr. Kelly and myself as to our respective duties on this occasion: The precedents are not clear as to whether the retiring or the incoming president is expected to speak at length. Mr. Kelly&apos;s argument was that as the incoming president confines himself to promises for the future his field is a broad one and his opportunities for extending his remarks correspondingly unlimited.

Jan 1, 1925

By Albert L. Toenges

COAL mining technique progressed slowly until the advent of mechanized mining. The cutting machine was a forward step, but had only a limited effect upon improving the percentage of coal recovery. Previously, the physical fitness of the loaders and the total output of the miners fixed mine production. The miner was an independent contractor and supervision over his working place was superficial. Rising costs and the inroads of substitute fuels demanded increased output per man to lower the unit production cost. Therefore, the amount of coal loaded mechanically in underground bituminous mines has risen from 0.3 per-cent in 1923 to 7.4 in 1929, to 20.2 in 1937, and to 48.9 percent in 1943. When loading devices were introduced it became necessary to adapt them to existing systems of mining, or to alter the mining system to fit the machine. An increased amount of supervision was required as output depended upon proper operation of the machine rather than on the physical fitness of the individual.

Jan 1, 1946

By R. H. Ogburn

THE GROUND now being worked by the Fairbanks Exploration Co., near Fairbanks, Alaska, has been known to be gold bearing since 1901. In the early days it was worked by drift mining and other small-scale methods. In 1922, Hammond started prospecting the gold-bearing ground and obtaining options on the properties desired. Two years later the present Fairbanks Exploration Co. started taking up the options, and preparing to exploit the ground. For the prospect drilling Keystone drills were used, with holes at the points of equilateral triangles 600 ft. apart. Holes were also put down more closely spaced to determine the limits of dredging ground. In the first drilling casing was used to the bottom of the holes, but in later work the casing was put down only to the bottom of the thawed ground, and the rest of the hole put down without casing. The gold content was determined by panning, each 2 ft. of depth being determined separately. Where no casing was used the size of the hole was determined by using water to measure its volume. The greatest concentration of gold occurs at or near bedrock. All the gold-bearing streams head in one big dome. Gold, however, is not found clear to the head of the creeks, the pay being first found some distance downstream from the head.

Jan 1, 1933

By Paul Weir

PRODUCTION METHODS in the bituminous coal mines in the United States are undergoing many changes. Although the primary object of these changes is the production of a better product at a cheaper cost there are other considerations such as the improvement of conditions under which miners live and work. The almost complete unionization of the manual workers in the industry during the past four years has &apos;brought with it a stabilization of wages on a relatively high basis and of hours of work per day and per week on a relatively low basis. With differentials in wages between producing districts firmly established, and with a nation- wide and uniform application of in-

Jan 1, 1937

By John G. Baragwanath

THE September issue of the Engineering and Mining Journal carried an item regarding the Cercapuquio Mining Co. which was mentioned as a large producer of lead, zinc, and cadmium, situated near Huancayo, Peru. The paragraph caught my eye because I had not heard of the property in thirty years and I recollect all too well the circumstances of its accouchement. In 1916 1 was making my headquarters in the town of Huancayo, then the terminus of the Central Railway of Peru, and was examining mines and prospects in that general area for Cerro de Pasco. In the course of my work I became acquainted with an engaging and energetic "practical" miner named Balarin, a Dalmatian living in Huan¬cayo, and made numerous trips in his excellent company. One day Balarin came to the down-at-heels hostelry where I stopped and told me that a Cholo prospector, a character by the name of Jose, had just reached town and claimed to have made a discovery in a little known locality called Cercapuquio. Lead-silver, Balarin said, and showed me a sample of galena about the size of his fist. "Fine," I remarked. "When do we leave?"

Jan 1, 1947

By Paul Queneau

FROM the first days on the Norman beaches to the last days on the Elbe the Army Engineers of World War II lived off the countryside for the great bulk of the construction supplies needed for the fulfillment of their ultimate mission-to keep the army moving. To accomplish this end, vast tonnages of rock, timber, and steel were required in the construction of roads, railroads, and bridges. Combat Engineer battalions operated quarries under shell fire as a routine matter. An Engineer forestry company was decimated while cutting bridge timber on the Siegfried line. Oneof the more spectacular feats of the Army Engineers in obtaining construction materials was the operation of the Hadir Steel Works during the fall and winter o f 1944.

Jan 1, 1946

By A. B. Kinzel

ALTHOUGH calcium carbide and other compounds of calcium, as well as a number of calcium alloys, are well known and are the basis of important industries in the of United States, calcium metal has been thought of as something of a rarity and has received comparatively little attention from industrial metallurgists. The metal may he made in a number of ways, but the electrolytic deposition of calcium from a molten calcium chloride bath was the first process to be used for its commercial production and is still the standard procedure. Calcium metal has elicited little interest among nonferrous metal producers, as the demand has been relatively small and its production restricted to only a few plants, exclusively in France and Germany.

Jan 1, 1941

By B. S. Old, E. R. Poor

PRODUCING more steel without major capital investment in new plants is one of the most perplexing difficulties which confront the nation&apos;s postwar steel industry. The lack of scrap at a reasonable price results in an especially heavy pressure being brought to bear on the pig-iron production facilities which consist of 245 blast furnaces scattered throughout the country but concentrated most heavily in the Pittsburgh-Chicago area. Present demands exceed the total optimum output of these existing blast-furnace plants. Management hesitates to authorize erection of new plants on a scale sufficient to satisfy &apos;the demand for pig iron for two main reasons: first, extensive building under the present high costs of construction would greatly increase . the over-all capital investment per ton of iron capacity; and, second, the amount of steel necessary for a major construction program would upset the already tight supply-demand situation. The answer to the problem would then seem to be the development and application of a method which would increase the capacity of existing blast furnaces with a minimum of alterations and expense. Experiments consisting of operating a blast furnace at higher-than-normal top pressures, as proposed by Arthur D. Little, Inc., were carried out by the Republic Steel Corp. initially during World War II, and much more extensively during the past twenty months. The results of the Republics trials indicate that pressure blowing is a solution to the problem of increasing pig-iron capacity without necessitating major changes to existing equipment.

Jan 1, 1948

By Donald H. McLauqhlin

ITEM expressed in billions of dollars have become so commonplace these day- that a mere statement of the latest figures for the country s gold reserve scarcely conveys m adequate sense of the immensity of the commitment the nation has made in building up its huge stock, two-thirds of which is now stored at Fort Knox. Kentucky. Only by measuring it against quantities that mean something tangible to a particular group can an adequate comprehension of its magnitude he rained; consequently, to mining engineers, a comparison with the value of output from well-known mining districts might best serve to give some degree of reality to the astronomical figure at which the country gold is now valued.

Jan 1, 1941

By Sheldon P. Wimpfen, Ralph H. Sweefser

FOR centuries the pumping of water has been one of the chief problems to be overcome by the persistent men who win the mineral wealth of the world. Profitable operations have often been forced to suspend activities as the mine penetrated well below the water table or when sudden rushes of water were encountered. To operate below the local water level requires continuous pumping equal in volume to the amount of water flow¬ing into the mine workings. Often the water to be removed exceeds the tonnage of valuable material produced. To be above local water level is a valuable asset. Modern mining practice permits nothing short of the extraction of the last pound of profitable ore from a mineral deposit. In the days before the development of mechanical and electrical power as we know it today. water in any quantity was a major

Jan 1, 1948

The annual meeting of the Woman&apos;s Auxiliary was held on February 19, at 10 a. m. The president, Mrs. Sidney Jennings, said in her greeting "it is a matter of congratulation that during the past year when the demands upon women for work of all kinds has been so large our membership has grown from the 50 enrolled at the first meeting a year ago to over 300 today. Some women, when. asked to join the organization, say that they are doing so much work in other ways that they have no time for work in a new organization, but the director for Canada struck the right note in her report when she told us of the splendid work the wives of mining engineers are doing in Canada, as individuals and as leaders and members of various organizations doing patriotic work. We do not want to divert such women from the work they are now doing, but we do want them to enroll as members of the Woman&apos;s Auxiliary and let us know what they are doing, that they play give inspiration to others." Reports were made by the directors of the following sections: Canada, Chicago, Colorado, Columbia, New York, Puget Sound and St. Louis, in some of which sections excellent progress has been made in food conservation, foreign war relief, including the adoption of fatherless French children, and in work for our own engineering regiments. These reports were read, accepted, and placed on file. The reports of the corresponding secretary, of the recording secretary, and of the treasurer, were read, accepted, and placed on file. Various amendments to the Constitution were proposed and accepted, and copies of the Constitution, as amended, will be mailed to all the members of the Woman&apos;s Auxiliary.

Jan 4, 1918

By Philip D. Wilson

FEAST and famine-or, chronologically, famine and feast-have characterized the aluminum supply program during 1943. Fortunately for the war effort the famine phase is over and aluminum production is now in the happy position of being abundantly able to supply all the requirements of the armed services plus a monthly surplus which is building up a substantial stock pile as a reserve against any contingencies. But the present condition of oversupply cannot be attributed to the super-efficiency of the aluminum production program which was designed to take care of the over-all requirements of the war with little or no margin of safety. The present more than comfortable situation is due primarily to the fact that the armed services generally have not consumed anything approaching the amount of aluminum which their requirement estimates indicated.

Jan 1, 1944

By Arthur M. Miller

FROM the time of its establishment in 1933, the Tennessee Valley Authority has been active in the field of phosphates. Under the T.V.A. Act it has a broad Congressional mandate to guide a unified development of the resources of the region for the long-range benefit of the people. As one phase of this function, it is directed to co-operate with farmers in the experimental large-scale use of improved fertilizers and development of better fertilizer practices. Following careful study, it was concluded that the objectives of this phase could best be attained by soil rebuilding through the use of phosphatic fertilizer and lime in an improved farm management sys- tem. This activity was launched through a program of test and demonstration on farms and simultaneous technical investigations to develop new and improved phosphatic fertilizers. Phosphorus has since become a keystone of the Authority&apos;s resource development and conservation program. Human effort is being conserved by phosphate utilization on the farm, and mineral conservation has been promoted by technical developments in phosphate mining and manufacturing operations.

Jan 1, 1944