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By C. P. Walker

Determining the distance to remote objects by observing the time required for sound to traverse the intervening space is an old practice. Attempts have been made to use this method for determining the fluid level in oil wells but as far as the writer is aware it was not found to be practicable, because vibrations in gas in the audible frequency range do not travel as well and as far as low-frequency pressure waves, which are capable of transmitting a greater amount of energy than can be transmitted by audible waves. Wood, in his book "Sound," states that in a given medium the range of sound transmission will vary inversely as the square of the frequency. The fact that the sound from a whistle having a low tone has a much lower attenuation rate than that from a whistle of high pitch is well known. Also, the pressure waves caused by cannon fire often rattle windows at points so distant that no sound of the cannon is heard. In 1932 P. E. Lehr and H. T. Wyatt, of the Shell Oil Co., experimented with the principle of the concussion, or pressure-wave echo, method of determining fluid levels in oil wells. They released compressed gas into the top of the casing, thereby creating a pressure wave, which traveled down the well and back again. Their experiments proved conclusively that, with the proper apparatus for recording the echoes and determining the velocities at which the waves travel, the method could be used successfully for determining fluid levels in oil wells. Wells are often equipped with from one to three tubing catchers and these together with the top of the liner are frequently above the fluid. Each of these obstructions reflects a part of the pressure wave. In such wells there may be, therefore, as many as five pressure-wave reflections. Thus it is obvious that in order to identify the various reflections and to determine therefrom the fluid level in a well it is necessary to obtain a graphic record of these reflections.

Jan 1, 1937

By Henry Phelps Howland

During the last decade no topic has created more interest or received more thought among blast-furnace men than coke. One reason for this is, undoubtedly, the remarkable increase in the use of byproduct coke. Formerly our coke was made at a distance from the furnaces and by a distinct organization. There was little cooperation or development possible under these conditions. Today the situation is greatly changed. Much of our coke is made by the organization operating the furnaces and the coke oven is operated with the primary object of obtaining the best results in the blast furnace. The effect of changing the method of coke manufacture, even in some minor detail, is often felt almost immediately at the blast furnace. There naturally results one of the most valuable assets of the byproduct coke oven, i.e., the possibility of increased blast-furnace efficiency due to close observance and correct operation of the ovens. The results are evident, but often it is difficult correctly to account for them. In attacking the solution of a problem of as much importance as why one coke is better than another, there are facts which should be kept clearly in mind. The author hopes, in this paper, to bring out some points relative to the use of carbon in the blast furnace which will be of value in solving this question. GeÜner's Ideal Working Years ago GrÜner made a statement regarding the use of carbon in the blast furnace, which has been very generally accepted by metallurgical and blast-furnace men. I quote this theory as given by Prof. Richards on p. 248 of Metallurgical Calculations: "From the standpoint of the generation of the maximum quantity of heat in the furnace, GrÜner was right in formulating his dietum of the ideal working of a blast furnace, vie.: All the carbon burnt in the furnaee should be first oxidized at the tuyères to CO and all reduction of oxides above the tuyères should be caused by CO, which thus beeomes Co2."

Jan 1, 1917

By R. S. Archer

In the microscopic examination of aircraft-engine parts made of heat-treated alloy steels, the writer has been forcibly impressed by the failure of the usual etching processes to disclose any but gross defects in heat treatment. It seemed particularly desirable to bring out the grain size of the steel, which is indicated in the ordinary etching processes chiefly by the change in orientation of structure from grain to grain. After various attempts, a fairly successful method has been found, which is here presented in the hope that it may be of use to those who have occasion to examine these steels in the hcat-treated condition. The specimens worked with have been mostly chrome-nickel steels heat treated (that is, hardened and tempered) to a Brinell hardness of around 300. A few experiments with other specimens will be referred to later. Briefly, the method employed consists in etching the steel about 10 min. in a fresh solution of picric acid in ethyl alcohol, and then rubbing off the smudge of carbonaceous matter on moist broadcloth. Different samples of almost identical analysis, heat treatment, and physical properties (including resistance to impact) respond quite differently to this treatment. In some, the grain boundaries are developed quite readily, while in others, especially in those whose grain is unusually fine or in which the final hardening heat has not quite obliterated the previous crystallization, the results are more obscure. The exact time of etching to secure the best results also differs for various samples, and the greatest success is usually attained by a process of "tinkering." Such a process is illustrated in a series of micrographs, the first six of which were taken at a magnification of 300 diameters. The properties of the steel are as follows: Carbon, per cent............... 0.42 Brinell hardness.............. 293 Nickel, per cent................ 1.35 Yield point, pounds per square Chromium, per cent............. 0.90 inch........................ 131,000 Copper, per cent................ 0.025 Maximum strength, pounds per Manganese, per cent............ 0.74 square inch................. 144,500 Phosphorus, per cent............ 0.024 Elongation in 1 in., per cent... 28 Sulfur, per cent................ 0.036 Lod impact, foot-pounds...... 51 Reduction of area, per cent...... 57.3

Jan 1, 1920

By M. Schmellenkamp

By comparing two longwall operations, one begun in 1956 and the other in 1960, the author is able to demonstrate the increases in production and performance made possible by longwall mining. These achievements have been brought about by continuous development of longwall mining equipment and associated roof supports. Because of this progress, longwall mining is able to provide, under proper conditions, high production per man-shift, remarkable cost savings, dependable roof control, safe working conditions and truly continuous production. It may seem odd that the title of this paper is not simply "Longwall Mining" but instead "Progress in Longwall Mining." However, the word "Progress" definitely has its place in longwall mining. If it had not been for progress in the development of longwall mining equipment and roof supports, the longwall mining method would not be able to compete in production and performance with modem coal mining machines. The longwall mining method was practiced at the beginning of the century and there were several successful operations in coal fields in Illinois. In those early days of longwall mining, the coal was undercut by hand 2 to 2.5 ft at the bottom of the seam and packwalls were built in the gob to support the roof. The roof eventually subsided and the weight of the subsiding roof was used to ride the face and break the undercut coal. Utilizing natural weight to soften the coal face is still practiced in modern longwall mining; however, the packwalling method has been replaced by the caving method and the roof is now supported by yielding steel roof supports and forepoling steel headers. The purpose of these yielding-type roof supports is to provide a safe working area for the crew along the entire longwall face, to permit continuous mechanical mining across the prop free face, and to provide a strong resistance for the roof by forming an even breaking line at the gob for the roof to cave. Roof supports and associated forepoling headers should be kept as close as possible to the face in order to prevent a caving between face and supports, especially under friable roof. This means that the coal should be extracted in small slices, allowing only a narrow roof area to be exposed and unsupported. The coal planer with its relatively high cutting velocity of 75 ft per min provides such an extraction of coal and has proved its high performance under difficult mining conditions. Since 1951, several longwall faces in southem West Virginia and Pennsylvania which have been equipped with the coal planer and friction-type manual roof supports have been successfully operated. Compared to today's longwall mining, these longwall faces required such a large crew, primarily to handle the roof supports, that the actual high production per shift was charged with too high a labor cost, thereby decreasing the tons per man. Yet, even then the longwall faces outperformed the conventional mining system under the same conditions. In order to demonstrate the progress that has been made in the development of longwall mining, a comparison will be made between a longwall face in Arkansas which was installed in 1956 and a modemized longwall face started in 1960 in southern West Virginia. LONGWALL MINING IN 1956 The 320-ft longwall face was developed in a 32-in. thick coal seam near Greenwood, Ark. The method of mining the 320-ft coal block was the advancing system in which three entries on either side of the face were driven ahead of the advancing longwall face. The face was equipped with a coal planer and a Panzer conveyor; timbering was done with wooden timbers and cribs. The roof supports were set without any pattern. The crew to operate the planer and to handle the roof supports (timbers and cribs) consisted of 15 men per shift. During a period of approximately eight monthsof single shift operating time, the average tonnage produced in this relatively low seam amounted to about 263 tons of clean coal per shift. To show the development in the coal plow from then until now, it should be pointed out that the standard plow was used in this operation. The plow was equipped with rigid bottom bits which could not be adjusted if the plow started to climb, thereby leaving bottom coal to be recovered by pick hammers end causing delays in production. The height of the plow

Jan 1, 1963

By Michel T. Halbouty

South Texas, one of the world's important oil and gas-producing areas, continued to hold interest during 1939 as another scries of new fields and new producing levels was developed within its boundaries at a fairly continuous rate throughout the year. There were 1801 wells drilled in this area in 1939, compared to 1678 in 1938; of these, 1515 were drilled in established fields, or as extensions to proven areas (semi-wildcat), and 286 were drilled as rank wildcats, in search of new production. Among these rank wildcats, 22 produced oil, 7 produced distillate and gas and 257 were abandoned as dry holes (see Table 5). Of the 1515 field and cxtension wells, 1213 produced oil, or distillate and gas, 50 produced only gas and 252 were dry; 38 found new productive sand levels in proven ficlds. Jim Wells County led this district in discoveries, having had 9 new fields arid 9 new productive sands found within its border during 1939. Most activc of the 1939 discoveries were Reynold?; and Ben Bolt fields in Jim Wells County and Minnie Bock field in Nueccs County; among producing fields the most activc were: East White Point and Aransas Pass (McCampbell). Production from South Texas in 1939 totaled 55,105,506 bbl. against a total of 56,152,122 bbl. produced in 1938. South Texas should continue its present rate of developrnent and exploration and this should result in the discovery of many fields in its numerous oil-bearing zones, and should also lead to more knowledge of the possibilities of its deeper horizons, such as the Mt. Selman and Wilcox formations; with the latter holding particular interest at the present time. Tide Water Associated Oil Company's A. M. Bruni No. I, Cole-Bruni field, Webb County, the deepest well drilled along the Mirando trend, was carried to 8959 ft., where it started to blow out from a Wilcox sand topped at 8954 ft., making gas, distillate and mud under heavy pressure. After the well was killed, drill stem beeame stuck and was cemented in place in order to test a Queen City (Mt. Selman) sand logged from 5620 to 5675 ft. This and other shows found in other wells along this trend, but out of this district, have served to increase the importance of this but little explored Sparta-Wilcox trend of South Texas during the year, and more activity along it is to be expected in the near future.

Jan 1, 1940

By Michel T. Halbouty

South Texas, one of the world's important oil and gas-producing areas, continued to hold interest during 1939 as another scries of new fields and new producing levels was developed within its boundaries at a fairly continuous rate throughout the year. There were 1801 wells drilled in this area in 1939, compared to 1678 in 1938; of these, 1515 were drilled in established fields, or as extensions to proven areas (semi-wildcat), and 286 were drilled as rank wildcats, in search of new production. Among these rank wildcats, 22 produced oil, 7 produced distillate and gas and 257 were abandoned as dry holes (see Table 5). Of the 1515 field and cxtension wells, 1213 produced oil, or distillate and gas, 50 produced only gas and 252 were dry; 38 found new productive sand levels in proven ficlds. Jim Wells County led this district in discoveries, having had 9 new fields arid 9 new productive sands found within its border during 1939. Most activc of the 1939 discoveries were Reynold?; and Ben Bolt fields in Jim Wells County and Minnie Bock field in Nueccs County; among producing fields the most activc were: East White Point and Aransas Pass (McCampbell). Production from South Texas in 1939 totaled 55,105,506 bbl. against a total of 56,152,122 bbl. produced in 1938. South Texas should continue its present rate of developrnent and exploration and this should result in the discovery of many fields in its numerous oil-bearing zones, and should also lead to more knowledge of the possibilities of its deeper horizons, such as the Mt. Selman and Wilcox formations; with the latter holding particular interest at the present time. Tide Water Associated Oil Company's A. M. Bruni No. I, Cole-Bruni field, Webb County, the deepest well drilled along the Mirando trend, was carried to 8959 ft., where it started to blow out from a Wilcox sand topped at 8954 ft., making gas, distillate and mud under heavy pressure. After the well was killed, drill stem beeame stuck and was cemented in place in order to test a Queen City (Mt. Selman) sand logged from 5620 to 5675 ft. This and other shows found in other wells along this trend, but out of this district, have served to increase the importance of this but little explored Sparta-Wilcox trend of South Texas during the year, and more activity along it is to be expected in the near future.

Jan 1, 1940

By J. H. Richards, G. Derge, W. Peifer

A WIDE Variety of metallurgical defects in steel have commonly been attributed to the presence of excessive amounts of hydrogen. These defects include flakes in rails and forgings, cracks in welds, and blisters in enameled ware, They have been related to hydrogen largely by circumstantiat evidence because the proper sampling and analysis of steel for hydrogen has been known to be difficult and because no general agreement has existed with regard to the relative suitability and accuracy of available methods. The need for a direct approach to these problems has been widely recognized. This general situation has been well described in the publications of the British committee on the Heterogeneity of Steel Ingots,' and current approaches to the problem were reviewed in a recent symposium of the AIME.I2 The plans described by the present authors at that meeting have now matured satisfactorily and will form the basis of this paper. The principal object of this paper will be to describe the methods of sampling and analysis which have been developed and to illustrate the usefulness and limitations of these methods by citing their application to a specific problem, The first problem selected for investigation was the behavior of hydrogen in rail steel. This was chosen because the occurrence of shatter cracks in rails has received a great deal of study over a long period of time. The defect can be controlled by the expensive procedure of slow in However, it may be hoped that a better understanding of the factors influencing the hydrogen content of rails will lead to a more efficient control of this problem. Rails provide a good starting point for a more general study of hydrogen in steel because they provide a cross-section large enough to develop cracks, Yet small enough for convenient handling and sampling. Rails were also selected because they arc made from plain carbon steel and it was felt that the initial work should not be complicated by the effects introduced by alloying elements. The considerations which determined the original planning of this study should be reviewed. The inherently complex nature of most hydrogen problems requires that a large amount of data must be collected for any particular case. This in turn means that any analytical procedure should be as rapid and simple as possible. The same objective of speed is indicated by the fact that it may finally become desirable to use hydrogen analysis in process control. It is also known that hydrogen is highly fugitive and that any procedure which facilitat~s early analysis of the sample without prolonged or irregular storage has distinct advantages. The most important previously reported methods of analysis may be classified into three general groups: (I) Vacuum fusion, (2) Vacuum extraction (without melting), (3) Total combustion.

Jan 1, 1949

By G. Derge, W. Peifer, J. H. Richards

A WIDE Variety of metallurgical defects in steel have commonly been attributed to the presence of excessive amounts of hydrogen. These defects include flakes in rails and forgings, cracks in welds, and blisters in enameled ware, They have been related to hydrogen largely by circumstantiat evidence because the proper sampling and analysis of steel for hydrogen has been known to be difficult and because no general agreement has existed with regard to the relative suitability and accuracy of available methods. The need for a direct approach to these problems has been widely recognized. This general situation has been well described in the publications of the British committee on the Heterogeneity of Steel Ingots,' and current approaches to the problem were reviewed in a recent symposium of the AIME.I2 The plans described by the present authors at that meeting have now matured satisfactorily and will form the basis of this paper. The principal object of this paper will be to describe the methods of sampling and analysis which have been developed and to illustrate the usefulness and limitations of these methods by citing their application to a specific problem, The first problem selected for investigation was the behavior of hydrogen in rail steel. This was chosen because the occurrence of shatter cracks in rails has received a great deal of study over a long period of time. The defect can be controlled by the expensive procedure of slow in However, it may be hoped that a better understanding of the factors influencing the hydrogen content of rails will lead to a more efficient control of this problem. Rails provide a good starting point for a more general study of hydrogen in steel because they provide a cross-section large enough to develop cracks, Yet small enough for convenient handling and sampling. Rails were also selected because they arc made from plain carbon steel and it was felt that the initial work should not be complicated by the effects introduced by alloying elements. The considerations which determined the original planning of this study should be reviewed. The inherently complex nature of most hydrogen problems requires that a large amount of data must be collected for any particular case. This in turn means that any analytical procedure should be as rapid and simple as possible. The same objective of speed is indicated by the fact that it may finally become desirable to use hydrogen analysis in process control. It is also known that hydrogen is highly fugitive and that any procedure which facilitat~s early analysis of the sample without prolonged or irregular storage has distinct advantages. The most important previously reported methods of analysis may be classified into three general groups: (I) Vacuum fusion, (2) Vacuum extraction (without melting), (3) Total combustion.

Jan 1, 1949

What has happened to the basic coal industry during the past year? Has it been a better year for coal than 1961? What striking new developments have occurred in mining, preparation and utilization? Are there positive signs that production will go up? What has happened in the utility market, the metallurgical market and the export market? Is the controversial question of coal transportation nearer to a solution? What progress has research made for coal during the year? The answer to these and many other important questions are offered in the following review of the Coal Industry-1962.

Jan 2, 1963

By Harry C. Swanson

TRANSPORTING concrete from mixer to forms has always been a problem. Twenty-five years ago this task was generally accomplished by means of wheelbarrow or concrete buggy. On large dam jobs, as the number of these projects increased, the gantry crane or highline came into use. Today several methods of handling concrete are employed on smaller surface construction jobs, for example, transit-mix trucks or dumpcrete trucks, which have crawler cranes with buckets for placing concrete into forms. In 1944, during early stages of developing Mather mine A shaft, several large underground concrete jobs were necessary. At this time the Cleveland-Cliffs Iron Co, purchased the first pump-crete machine, introduced by the Chain Belt Co. of Milwaukee. The machine was used to pour approximately 200 cu yd of concrete for a dam, or bulkhead, located 400 ft from the shaft. Concrete was mixed on surface, lowered down the shaft 1000 ft in a 2-cu yd bucket hung under one skip, spouted into the bowl of the pumpcrete machine from the bucket, and pumped directly into the forms. Since the day of the first pipeline concrete in 1944 to the present time, other equipment and other methods have been developed to permit transportation of concrete by pipeline through vertical and horizontal distances totaling 1 mile from mixer to forms. Much of the efficiency in present handling of underground concrete can be credited to the Bethlehem Cornwall mines, where concrete was transported through 6-in. pipe for great distances down an inclined shaft and along levels into forms.' During initial development of Mather mine B shaft, with concrete work under way on two or more levels at one time, the pneumatic concrete placer, Fig. 1, was selected as best adapted for underground concrete transportation. The 3/4-cu yd pneumatic placer is a small machine readily moved from one location in the mine to another. It can be equipped with two sets of mine car wheels, which will permit moving on regular mine tracks. It is therefore possible to send concrete through the pipe at great velocity; the pipeline is clean after each shot except for the film of cement adhering to the inside. With the proper slump in the concrete, it is possible to shoot concrete 2000 ft with this machine, using the mine supply of compressed air at 95 psi. This equipment was first used at Mather mine B shaft to concrete slusher drifts, Figs. 2 and 3, and finger raises located about 2000 ft from the shaft. In several instances there were bends into crosscuts and up vertical distances into the forms. For the first pours two placers were used. The first was located near the shaft where the concrete could be spouted into it from a 2-cu yd concrete bucket on the cage. The second was set on the side of the drift at a point approximately 1500 ft from the shaft. The concrete was shot directly into the second placer from the first unit and from the second machine directly into the forms. After completion of several pours with the two machines, a trial pour with only one placer located at the shaft proved that the second placer could be eliminated. Since then all pours have been successfully completed with only one placer underground. As production of iron ore from the mine increased and the development program expanded, use of the cage for handling mine supplies and concrete became a major problem. This brought about the first attempt at shooting concrete vertically down the shaft for 2600 ft. A 6-in. pipeline with victaulic couplings installed during shaft sinking was used for the trial. One placer was set on surface 250 ft from the collar of the shaft so concrete could be spouted directly into it from the mixer. This machine shot the concrete 250 ft horizontally on surface to the shaft, 2600 ft vertically down the shaft, and 100 ft horizontally into the second placer located near the rib of the shaft station or plat. The second machine shot the batch into the forms, about 2000 ft. Total distance horizontally and vertically was 4800 ft. The entire time cycle for a ¾-cu yd batch of concrete from the mixer on surface to the forms underground totaled about 5 min. During the past two years the two-placer method from the mixer on surface to the forms underground has proved a very efficient means of transporting underground concrete. Advantages of using pipeline concrete are as follows: 1—Interference with normal mining operation is eliminated. When the cage, skips, mine cars, or mine openings are used for transporting concrete and materials used for making concrete, mine operation suffers in one way or another.

Jan 1, 1955

(Members are urged to send in for this column any notes of interest concerning, themselves or their fellow-members.) Members and visitors who registered at institute headquarters during October A. Adiassewich, St. Petersburg, Russia. Charles W. Merrill, San Francisco, Cal. A. F. Lucas, Washington, D. C. Carl J. Trauerman, Butte, Mont. Allan J. Clark, Lead, S. D. Herbert B. Cox, Boston, Mass. Prof. Loewinson-Lessing, St. Peters- James W. Malcolmson, Kansas City, Mo. burg, Russia. A. E. Sunderhauf, Paramaribo, Dutch F. Maury Gillespie, Abangarez, Costa Rica. Guiana, S. A. M. Gardner Talcott, Irvington-on-Hudson, N. Y. D. W. Brunton, Denver, Colo. A. P. Watt, Newark, N. J. Dwight E. Woodbridge, Duluth, Minn. S. A. Taylor, Pittsburg, Pa. Alexander Fyfe, Boston, Mass. Ralph Wilcox, Miami, Ariz. Robert A. Seip, Wilkes-Barre, Pa. William J. Cox, Denver, Colo. A. J. Eveland, Boston, Mass. E. P. Ross, Duquesne, Pa. M. F. Sayre, Brewster, N. 1. H. Mortimer-Lamb, Montreal, Canada. Albert Sauveur, Cambridge, Mass. F. L. Grammer, Leesburg, Va. Robert H. Leach, Brockton, Mass. R. R. Moore, Mexico City, Mex. Steinar Foslie, Kristiania, Norway. Charles E. van Barneveld, San William A. Wong, Honolulu, Hawaii. Fran¬cisco, Cal.

Jan 11, 1913

By C. J. Rodgers

The present day success of gravel packs to prevent or retard the migration of unconsolidated sands into the well bore is due to: (I) the use of a saline or non-aqueous, nonsolids drill fluid, (2) proper preparation of the well bore prior to gravel packing, and (3) pressure placement of the gravel. The experience gained from the "pressure pack" method of gravel packing indicates that sand-free fluid production can be maintained for a length of time sufficient to make the operation economically attractive. Data pertaining to the first 15 wells so completed by Gulf indicate that for each dollar spent to effect the completion, there will be a return of more than $2.92. The pressure pack technique of gravel packing is essentially the placing of gravel in and adjacent to the producing formations. This is done with fluid pressure and by the use of a drill fluid that will permit partial or complete loss of returns to the formation during placement. This technique was first intentionally used by Gulf in May, 1950, and since that time has been applied in more than 90 wells. Other advantages claimed for this type of completion are that the pressure placement of the gravel has a scouring effect on the casing perforations, that additional drainage channels to the well bore are created, and that the possibility of shifting of the formations adjacent to the casing is minimized and possibly prevented. During the past few years, the use of gravel to prevent or retard the migration of unconsolidated sands into the well bore has met with a favorable degree of success. Numerous methods and techniques of "gravel packing" have been used, each having its own relative merits, and with varying results. M. L. Cashion1 in 1939 ably reviewed the history of gravel packing to that time. As stated in his paper, ". .. the idea of gravel packing wells is not new." During the period 1939 to 1949, very little if any progress or change in technique in this type of completion was made. However, it was noted in some cases that during the placement of gravel, if there was a loss of drill fluid to the formation, there was a corresponding loss of gravel to the formation. Also, it was noted that in those gravel-packed completions (opposite casing perforations) that "sanded up," there was found to be an absence of gravel in the annular space between the liner and casing, although gravel had previously been placed in this space and no gravel had been removed from the well at the surface. These findings resulted in the placement of gravel with fluid pressure and by the use of a drill fluid that would permit partial or complete loss of returns to the formation during placement. Pressure placement of gravel became an accepted practice in late 1949 and early 1950. Another fact brought to light that has contributed to the current success of gravel pack completions is that drilling fluids containing solids will to some extent cause plugging of the screening medium or blocking of the producing section. The removal of these solids by chemical action, mechanical action, or a combination of the

Jan 1, 1955

By C. Gatlin, F. Armstrong, K. E. Gray

This paper presents some preliminary results of two-dimensional cutting tests of dry limestone samples at utmospheric pressure. Cutting tips having rake angles of + 30°, + 15", 0°, - 15" and - 30" were used to make cuts on Leuders limestone samples at six depths of cut ranging from .005 to ,060 in. at cutting speeds of 15, 50, 109 and 150 ft/min. The vertical and horizontal force components on the cutting tips were recorded with an oscilloscope equipped with a polaroid camera. Motion pictures of the cutting process at camera speeds of 5,000 to 8,000 frames/sec were taken at strategic points in the variable ranges. The movies provide considerable insight into the brittle failure mechanism in rocks. It appears that chip-generating cracks usually have an initial orientation which is related to the resultant of the externally applied forces. The latter part of the crack curves upward toward the free surface being cut, this part being governed by some type of cantilever bending or prying. The linear and angular motion of the loosened chips also indicate the tensile nature of brittle failure. Analyses of the forces on the cutting tips indicate that: (I) relatively small increases in vertical loading result in large cut-depth increases for sharp tips (rake angles 2 0"); (2) tool forces increase at an increasing rate as the rake angle decreases, particularly for rake angles < 0"; and (3), for the range of this study, rate of loading had little effect on the maximum forces. Both the movies and visual inspection of the cuttings indicated that the volume of rock removed by chipping was much larger than that by any grinding mechanism, even for tips having negative rake angles. Cutting size increases with increased cut depth and rake angles, and decreases slightly at high cutting speeds, the depth of cut having by far the most influence. The amount of contact between the rock and the cutting tip was always less than the depth of cut and rarely exceeded 0.010 in. even for cuts of 0.060 in. INTRODUCTION The planing (or slicing) of various materials with a fixed blade has long been practiced by workers in many industries. For example, the farmer&apos;s plow, the carpenter&apos;s plane and the housewife&apos;s paring knife all employ this basic action. The casual observer might suspect that something so common must be quite simple; however, as in all problems involving the failure of materials, such is not the case. Industries concerned with the machining of metals have long studied these problems, and their literature on the subject is voluminous. Despite these efforts, basic knowledge is not very advanced, as may be noted from recent and comprehensive analyses of their literature.12 Metals are more subject to analysis by classical theories of elasticity and/or plasticity than are rocks, since their elastic constants and strengths are reasonably well established in many cases. In spite of this relative "simplicity", Hill9 refaces his discussion with an admission that the mathematical solution to the machining problem is not known. Photoelastic studies of both machining and milling have been performed and are discussed thoroughly by Coker and Filon.4 Rotary drilling of rocks with fixed blade or drag bits has long been practiced by the mining and petroleum industries, and considerable study has been given to defining their cutting action in terms of the pertinent variables. Essentially all the published mechanistic research on drag-bit drilling has been performed by mining engineers and has been concerned only with rocks in the brittle state. Fairhurst5-7 has worked extensively in this area and employed photographic techniques quite similar to those reported here, except at much lower speeds. His studies showed the periodic or cyclical nature of the brittle failure mechanism, in which instantaneous loads on the bit varied from some maximum value to near zero. Goodrichs has presented further data on the subject as well as a qualitative description of the process. Again the postulated mechanism is cyclical, with alternate chipping and grinding periods. The ploughing of coal is a practiced method and has been studied in some detail by English mining engineers."" Their findings have considerable general application to drag-bit drilling. Evans," in particular, has extended Merchant&apos;s metal-cutting theory" to brittle materials with some success, although certain aspects of his theory are open to question. Fish13 has recently summarized nearly all the published works concern-

Geology, by O. D. Von Engeln and Kenneth E. Caster, McGraw Hill Book Co., Inc., $7.00, 730 pp., 1952.The authors desired to write a book which would supplement the work of the teacher. The effort presents the facts of historical geology as an outgrowth of the understanding of physical geology-a method in keeping with the fundamental law of geology that "present agencies and forces, acting through enormous time, have shaped the world as we see it-the law of uniformitarianism." Narrative continuity is maintained throughout the text. Each historical geology period is made distinctive, provided with an identity, and shown to have particular characteristics. Elementary Heat Power, second edition, by Harry L. Solberg, Orville C. Cromer, and Albert R. Spalding. John Wiley & Sons, 1952. $6.50, 624 pp. The authors attempt to develop an understanding of the functions, principles of construction, and actual performance of heat-power machinery as a preliminary to the study of engineering thermodynamics. Matter and energy, fuels, and combustion are considered first, followed by chapters on internal combustion engines, fuel burning equipment, and steam engineering and utilizing installations. Pumps, compressors, gas turbines and refrigeration are also dealt with.

Jan 1, 1952

Discussion of the paper of WALTHER MATHESIUS, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 539 to 555. JOSEPH W. RICHARDS, So. Bethlehem, Pa.-This paper answers. partly the difficult questions which have come up as to why it is not economical to use higher blast temperatures in the smelting of Mesaba ores, such as the high temperatures used in European practices, and the answer is very plain that the ores will not stand the higher temperature. But the paper does not go into detail as to what special difficulties were found with the higher temperature of blast, and I would ask the author to kindly specify them. W. A. FORBES, New York, N. Y.-A large part of the troubles that furnace men experienced in using high-blast heats in smelting Mesaba ores in the early days of using Mesaba ores, was clue to the attempt to use these soft ores on furnaces having the same lines as the furnaces used in smelting the hard Old Range ores. As the result of observation and study, the dimensions of the lower part of the blast furnaces have been changed and the difficulties of the blast-furnace men in operating with a large percentage of Mesaba ore and high-blast temperatures have been largely overcome. The changes I refer to in particular are: (1) steepening the angle of the bosh; (2), decreasing the height of the bosh; (3) increasing the diameter of the hearth. JOSEPH W. RICHARDS.-Mr. Forbes&apos;s answer is quite satisfactory, and the moral which it points is that when the furnace is run with a higher temperature in the smelting zone, the furnace lines which were adapted for the lower temperatures are not necessarily those best suited for the higher hearth temperatures. If. enriched blast were used in a furnace, and higher temperatures run, it would be found necessary to further modify the lines of the furnace to meet the new conditions and to get the maximum output with economy. J. E. JOHNSON, JR., New York, N. Y.-It seems to me this is one of the few papers which could well have been a little longer. The data which Mr. Mathesius has given us, I think should be considered in connection with the paper which Mr. Brassert read before the American Iron and Steel Institute last spring, in which he described how they had obtained remarkable results with furnaces with steep but very short boshes; the angles have been raised to 80°, and the boshes made so short that they no longer appear as a conspicuous part of the shape of the furnace.

Jan 5, 1915

By Emby Kaye

IT is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and. Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the function of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. SOME ECONOMIC FACTORS The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves. in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercompressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreciate the variables in sampling gas from

Jan 1, 1941

By J. C. Rengel

Why and how the nuclear industry entered the electric power generation business is discussed in terms that nuclear energy was an undoubtedly additional energy resource and that it had promise of becoming a virtually inexhaustible generating power if breeder reactors could be devised. The growth of nuclear power, its total generation capacity, are related to the need of increasing energy requirements. The use of atomic energy for power generation will grow if it can compete economically with other fuels. The rate of growth, the time scale and direction of technical development is dependent on ore supplies. It is predicted that by 1980, 50% of all new power installations will be nuclear stations. INTRODUCTION Ten years ago, the nuclear industry was virtually unborn, the Atomic Energy Act of 1954 had just been signed, and peaceful applications of atomic power was little more than a phrase. Serious discussion of the practical application of nuclear energy to electric utility installations in the West was highly unlikely. The questions: Why and how did the nuclear industry enter the electric power generation business at all?; What is the predicted growth of nuclear power?; What technological changes do we predict?; How will the above changes affect the utilities? will in part be answered by this paper. WHY NUCLEAR POWER? The only justification for the West as for any other section of the country for atomic power is economics. Whatever energy source will provide the lowest generation cost will prevail; the only electric utilities which have shown an interest in nuclear power are those to whom it means lower generation costs. It is true that the Government sponsored the development of this technology long before there was any evidence of better economics; but a Government must take a very long-range view and it is the only type of organization that can afford to look more than twenty or thirty years into the future. The Government looked at projections such as shown in Fig. 1, which shows various rates of energy consumption, and matched these against estimates of fossil fuel resources. This showed that we will exhaust our low-cost fossil fuel supplies within 75 to 100 years and our total known fuel supplies within 150 to 200 years. The decision to invest in nuclear energy rested, therefore, on two arguments: a) It was undoubtedly an additional energy resource; and b) It has promise of becoming a virtually inex-haustable resource if breeder reactors could be devised if, while generating power, the reactors would produce more fissile materials than they consumed. This decision produced an unexpected bonus: nuclear power became competitive with fossil power much earlier than had been expected and, as shown in Fig. 2, forced the coal industry to take a hard look at its own position. I believe that the drop of coal prices shown here is the direct result of the entry of nuclear power into the energy supply business. At this point, it ought to be explained why and under what conditions nuclear power can be cheaper than fossil power. Fossil fuel cost to the utility is composed of two factors: a) Mining; and b) Transportation. As a result, the cost of fossil fuel to the utilities varies from 126, 106 Btu to 306, 106 Btu and higher. Nuclear energy is highly concentrated and the transportation factor becomes insignificant. Today the cost of nuclear fuel to the utility ranges between 156

Jan 1, 1967

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By L. S. Darken

In the study of reactions occurring in liquid iron, alone or in contact with a liquid oxide or slag phase, it has been found that the experimental data over a limited range of concentration can in some cases be represented satisfactorily by the simple equilibrium expression where (P) denotes the concentration of a product and (R) the concentration of a reactant in the reaction r1R1 + r2R2 + • • • D P lP1 + P 2P2 + • • • Some of the reactions for which it holds are listed in Table 1. For others, however, the simple equation apparently does not hold. This has been attributed to an improper method of expressing concentration (for instance, weight per cent instead of mol fraction); or it has been supposed that the solutions are not ideal in the sense that the activity of a component is not proportional to its true mol fraction. But it may be that the problem has been oversimplified by neglecting some molecular species actually present; that is, by considering only the ostensible simple components and thus leaving out of account possible compound formation. It is the purpose of the present paper to point out how, in a group of related cases, a reasonable consistent assumption relative to the presence of a compound makes it possible to express the experimental data satisfactorily by the simple equilibrium expression when this compound is taken into account, and to bring into harmony data referring to different reactions in liquid iron. There are several a priori reasons for believing that solutions in liquid iron should not deviate far from ideality, provided that the concentration of solute is not too great and is expressed in proper terms. The factors that commonly lead to nonideality in systems at ordinary temperature— as ionization or the occurrence of polar and nonpolar molecules—are presumably less effective in inetal and in slag systems at high temperature. Again, the type of equation commonly used to express the value of

Jan 1, 1940