Search Documents

By O. J. Neslage, R. W. Jenkins

MINE operators today are paying increased attention to the mechanization of drilling operations as an important factor in increasing efficiency and decreasing costs. Recent progress in the design of drill jibs for mounting on drill carriages, or jumbos, has done much to advance the mechanization of mining methods. This progress has introduced new opportunities in the application of "jib jumbos" that are worth serious consideration. An attempt will be made here to classify the various types of jumbos and drill mountings available for level development and flat stope work, t6 indicate applications, and to measure their effectiveness in relation to their cost. The data here are based on a wide variety of field usage, and are offered only to point up, in a general way, the relative efficiency in proportion to cost. It should be remembered that any contemplated jumbo installation must be studied to determine what type of installation is most suitable, considering ground conditions, loading, timbering and haulage equipment, service available, and attitude of manpower. Early Drill Carriages: The advantages of some sort of a drill carriage were recognized at the time rock drills were introduced. In drift or heading operations where a fairly standard drill round and cross section were anticipated, as well as in flat bedded deposits where standard slabbing rounds were used, track and crawler-mounted drills found an early application. These first drill jumbos were little more than drill carriers, designed locally and manufactured with materials at hand. Of comparatively simple construction, function, and low capital cost, they usually consisted of a hinged column which supported one or more drills on arms or universal bars. When the column was pivoted vertically, the drills were moved into position. Screw jack extensions reached from the column to the roof and floor to hold the drill rigid. In some cases, particularly in tunnel jumbos, enough weight was carried that rail clamps or roof jacks were sufficient. Many of these column and arm-type jumbos, usually equipped with air and water manifolds, steel racks, and staging for drillers, are still in use today. Some have employed air or hydraulic extensions for securing the columns. They offer the equip-saving advantage of having all the necessary out, ment together, and they un be moved i and t. set up and torn down as a unit. Boom-type Jumbos: When the advantages of to column-type jumbo were seen, operators could to realize the further gains possible. More time could be saved with mechanical assistance to position api drill vertically. A rack on the column and a pinion on the arm for raising and lowering the drill in the manner of a quarry bar were tried with some success. The most outstanding solution to the vertical handling problem was reached with the boom-type of jumbo. Here two or more machines were mounted on a cross arm at the end of a boom that was pivoted at the rear of the track. This was raised and lowered by various mechanical aids. Occasionally air or hydraulic power was used. Nearly all of today's wagon drills use this boom-type principle. Boom jumbos represent a savings in time and physical effort expended in raising and lowering the drills. The boom must be balanced by the roof of the truck which is secured by rail clamps or type jacks. The most successful application of areawhere this of jumbo has been in the Tri-State area where multiple long-feed machines are used on caterpillar-mounted, boom-type jumbos for slabbing

Jan 1, 1951

By R. W. Jenkins, O. J. Neslage

MINE operators today are paying increased attention to the mechanization of drilling operations as an important factor in increasing efficiency and decreasing costs. Recent progress in the design of drill jibs for mounting on drill carriages, or jumbos, has done much to advance the mechanization of mining methods. This progress has introduced new opportunities in the application of "jib jumbos" that are worth serious consideration. An attempt will be made here to classify the various types of jumbos and drill mountings available for level development and flat stope work, t6 indicate applications, and to measure their effectiveness in relation to their cost. The data here are based on a wide variety of field usage, and are offered only to point up, in a general way, the relative efficiency in proportion to cost. It should be remembered that any contemplated jumbo installation must be studied to determine what type of installation is most suitable, considering ground conditions, loading, timbering and haulage equipment, service available, and attitude of manpower. Early Drill Carriages: The advantages of some sort of a drill carriage were recognized at the time rock drills were introduced. In drift or heading operations where a fairly standard drill round and cross section were anticipated, as well as in flat bedded deposits where standard slabbing rounds were used, track and crawler-mounted drills found an early application. These first drill jumbos were little more than drill carriers, designed locally and manufactured with materials at hand. Of comparatively simple construction, function, and low capital cost, they usually consisted of a hinged column which supported one or more drills on arms or universal bars. When the column was pivoted vertically, the drills were moved into position. Screw jack extensions reached from the column to the roof and floor to hold the drill rigid. In some cases, particularly in tunnel jumbos, enough weight was carried that rail clamps or roof jacks were sufficient. Many of these column and arm-type jumbos, usually equipped with air and water manifolds, steel racks, and staging for drillers, are still in use today. Some have employed air or hydraulic extensions for securing the columns. They offer the equip-saving advantage of having all the necessary out, ment together, and they un be moved i and t. set up and torn down as a unit. Boom-type Jumbos: When the advantages of to column-type jumbo were seen, operators could to realize the further gains possible. More time could be saved with mechanical assistance to position api drill vertically. A rack on the column and a pinion on the arm for raising and lowering the drill in the manner of a quarry bar were tried with some success. The most outstanding solution to the vertical handling problem was reached with the boom-type of jumbo. Here two or more machines were mounted on a cross arm at the end of a boom that was pivoted at the rear of the track. This was raised and lowered by various mechanical aids. Occasionally air or hydraulic power was used. Nearly all of today's wagon drills use this boom-type principle. Boom jumbos represent a savings in time and physical effort expended in raising and lowering the drills. The boom must be balanced by the roof of the truck which is secured by rail clamps or type jacks. The most successful application of areawhere this of jumbo has been in the Tri-State area where multiple long-feed machines are used on caterpillar-mounted, boom-type jumbos for slabbing

Jan 1, 1951

By Alan C. Noble

INTRODUCTION Forecasting of metal and mineral prices is a complex and hazardous undertaking. In order to accurately forecast prices, the complexities of both marketing and production must be modeled for each commodity. Even with the most detailed model, the economy may change unexpectedly, invalidating the forecast. Because of these factors, this chapter will not attempt to present specific methods for price estimation. It will, however, review the fundamentals of price forecasting as applied to planning and design of the final pit shell. Recognizing that no price estimate can be exact, sensitivity analysis will be reviewed as an approach to coping with these unknown variations.

Jan 1, 1979

By W. E. C. Eustis

1st. The fine iron ore is mixed with a sufficient proportion of fine coking coal, and is coked in any of the ordinary methods for making coke. The effect of this is to convert the iron oxide into sponge in such a shape that the usual trouble of oxidation is avoided. 2d. The resulting mixture of coke and sponge is melted down ill an ordinary cupola, the coke furnishing more than sufficient fuel for that purpose. I may briefly point out here that in the first place the iron is sponged, and this sponge, as is well known, contains no phosphoras or silicon when the reduction takes place at a low temperature; and in the second place this sponge is melted down in a cupola in which there is no zone of reduction for phosphorus or silicon, and that con . sequently the resulting iron should be free from both of these impurities. 3d. The liquid sponge, now carburized, is run into an open-hearth furnace, where the requisite degree of hardness or softness is obtained by adding some of the fine ore, and the usual dose of ferromanganese, I have merely given above the rough outlines of the prows, bat it is my intention, as early as possible, to bring the process more fully before the Institute.

Jan 1, 1881

By Keith E. Robinson, Brian Stimpson

INTRODUCTION In inclined sedimentary strata slope failure may occur by sliding along bedding and along a discontinuity or weak zone, as illustrated in Fig. 1. This mode of failure may be called 'bi-linear', as the failure surface is comprised of two linear or approximately linear segments. This type of failure has been suggested for the famous Frank Slide, Alberta, Canada (Cruder and Krahn, 1973) in which an estimated 90 M 5 tons (8.97 x 10 MN) of rock separated from Turtle Mountain and buried the town of Frank. Also, with the increasing depth of open pits and the construction of highways through inclined sedimentary strata this mode of failure is of major concern to the rock slope stability engineer. A computer program for calculating factors of safety for this slope failure mode is provided and includes the ability to vary shear strengths of potential slide surfaces, ground water elevations and wedge geometry. LIMITING EQUILIBRIUM MODEL The simple limiting equilibrium model used in the analysis is shown in Fig. 2. It is assumed that jointing is orthogonal to bed- ding and that the interface between the upper and lower wedges there- fore corresponds to a joint plane or planes. No shear strength is attributed to the interface so that the resultant force, P, from the upper wedge acts normally across the interface. The normal loads

Jan 1, 1983

By Arthur Wade

The most important development in connection with the search for oil in Australia during 1940 was on the legislative side. Prior to 1939 legislative enactments in the various states with regard to prospecting for petroleum were such as to prohibit large-scale effort and to bar the major oil companies from operating. The preparation of the Wade Model Bill for the Commonwealth Government in 1939 and the acceptance of the Bill in principle by all States, has gone far to remove these obstacles. Amending Acts, largely based on the Alodel Bill, have now been passed by all States with the exception of New South Wales and Tasmania. In New South Wales an Amending Bill is being drafted, while the Govern-ment of Tasmania is preparing to introduce an Amending Bill provided there is any demand for it. Noteworthy developments followed immediately on the passing of these Amending Acts. The Shell Company (1)1 and the Superior Oil Company of California (2) too$ up large areas in Queensland and com-menced work during 1940. Caltex acquired a big tract of country in the Kimberley district of Western Australia (3) and has made application for an area in the Territory of Papua. An Australian company, The Phoenix Oil Extraction Co., has obtained a permit to prospect over an extensive area bordering the south coast of Western Australia (4). Other developments are foreshadowed. The Shell Company is making an intensive examination of its area in Queensland (I). Geological, geophysical and aerial surveys are in progress. Caltex has three geological parties in the held in Western Australia while Superior Oil Company of California has done some geological work in the interior of Queensland (2). None of these concerns envisages a drilling campaign in the near future. Much exploratory work is necessary. Further work has been done by the companies that were already operating in 1939, though an important Australian company - Oil Search—has abandoned the work of prospecting in Australia. This company has subleased its holdings, at North West Cape in Western Australia (;), to Caltex on a royalty basis. The company also maintains its holdings in, and connection with, the Australasian Petroleum Company Proprietary Limited, which is a combination of Standard Oil (New Jersey), Anglo-Iranian and Oil Search. This company is operating in the territories of Papua and New Guinea. Drilling Victoria.—Although a good deal of drilling was done in the LaBes Entrance Tertiary Basin of Victoria (7), no appreciable production of oil was obtained. In order to test the extent and possibilities of the oil-bearing sand in this region, the Commonwealth and State Governments jointly put down six scout boreholes to depths of between 1200 and I500 it. The results were nega tive. A deeper exploratory horehole put down by the Governments at Seacornbe, or 26

Jan 1, 1941

By Arthur Wade

The most important development in connection with the search for oil in Australia during 1940 was on the legislative side. Prior to 1939 legislative enactments in the various states with regard to prospecting for petroleum were such as to prohibit large-scale effort and to bar the major oil companies from operating. The preparation of the Wade Model Bill for the Commonwealth Government in 1939 and the acceptance of the Bill in principle by all States, has gone far to remove these obstacles. Amending Acts, largely based on the Alodel Bill, have now been passed by all States with the exception of New South Wales and Tasmania. In New South Wales an Amending Bill is being drafted, while the Govern-ment of Tasmania is preparing to introduce an Amending Bill provided there is any demand for it. Noteworthy developments followed immediately on the passing of these Amending Acts. The Shell Company (1)1 and the Superior Oil Company of California (2) too$ up large areas in Queensland and com-menced work during 1940. Caltex acquired a big tract of country in the Kimberley district of Western Australia (3) and has made application for an area in the Territory of Papua. An Australian company, The Phoenix Oil Extraction Co., has obtained a permit to prospect over an extensive area bordering the south coast of Western Australia (4). Other developments are foreshadowed. The Shell Company is making an intensive examination of its area in Queensland (I). Geological, geophysical and aerial surveys are in progress. Caltex has three geological parties in the held in Western Australia while Superior Oil Company of California has done some geological work in the interior of Queensland (2). None of these concerns envisages a drilling campaign in the near future. Much exploratory work is necessary. Further work has been done by the companies that were already operating in 1939, though an important Australian company - Oil Search—has abandoned the work of prospecting in Australia. This company has subleased its holdings, at North West Cape in Western Australia (;), to Caltex on a royalty basis. The company also maintains its holdings in, and connection with, the Australasian Petroleum Company Proprietary Limited, which is a combination of Standard Oil (New Jersey), Anglo-Iranian and Oil Search. This company is operating in the territories of Papua and New Guinea. Drilling Victoria.—Although a good deal of drilling was done in the LaBes Entrance Tertiary Basin of Victoria (7), no appreciable production of oil was obtained. In order to test the extent and possibilities of the oil-bearing sand in this region, the Commonwealth and State Governments jointly put down six scout boreholes to depths of between 1200 and I500 it. The results were nega tive. A deeper exploratory horehole put down by the Governments at Seacornbe, or 26

Jan 1, 1941

By V. E. Elliott, C. L. Meyette

THE conditioning of semifinished steel products such as billets, blooms, and slabs to remove surface defects before further processing to finished products is a necessary accompaniment to steel mill rolling operations. A knowledge of the kinds of defects which occur and of the conditions in melting, teeming, and rolling that may lead to their occurrence is favorable to the production of quality products. Surface defects may be classed as either of mechanical origin such as those that occur in the heating and rolling operations and include breaks, tears, guide marks, mechanical laps and the like, or they may have been in the ingot before heating and rolling. Examples of the latter are ingot cracks, blow-holes, scabs, and inclusions which lead to the numerous known types of seams -and surface flaws. Most of the common types of surface defects and methods for their identification by visual examination or by the aid of macro-etch tests are well known. The conditions which caused their formation are also appreciably understood and this knowledge has been instrumental in the establishment of methods for metallurgical control. There are, however, defects of doubtful origin. In any endeavor to trace the causes for their occurrence, the question of first concern is: I. Whether they were formed in the rolling procedure. 2. Whether they existed in the ingot prior to rolling. In the case of semifinished products which are rerolled to finished products there is also the question of whether they were formed in the primary or in the secondary rolling. In metallurgical laboratories where numerous or routine examinations of the quality of rolled products are made over the course of time, there will doubtless be many puzzling cases of defect origin. Microscopic examination of the defects may, however, reveal a characterizing condition that can be used to classify them broadly with respect to their origin. Such a condition has been observed and, after detailed investigation, is described here with the thought that it may offer a useable and relatively simple solution to a bothersome problem. BASIS FOR CLASSIFYING In this discussion the term "mechanical type defects" will be used to designate those that have occurred as a result of the rolling operations such as in rolling from the ingot to billets, blooms, or slabs or in rerolling to finished products. The term "steel type defects" will he used to designate those that were present in the ingot prior to primary rolling or that were in the semifinished product prior to secondary rolling to finished product. The basis for distinguishing between the two types of defects lies in the relative degree of subscale formation surrounding them. Subscale is defined' as a zone of

Jan 1, 1948

By J. B. Seabrook

The accompanying Fig 1 is a graphical scheme of intermediate accuracy for expediting interconversions of mol, weight, and volume percents. This chart consists of a family of curves of mol or atomic or volume percent plotted against weight percent, each curve in the family providing for a certain ratio of molecular or atomic weights or densities. Thus, the whole range of variations is presented in a very familiar format, and the conversion is effected simply by choosing the proper curve and reading off the required values. An entire series of conversions for a given binary system can be found by following the appropriate curve. It is interesting to examine the analytical geometry of the plots. The curves, which must fit into a square and all join at the 0 and 100 pet points, may be shown to be hyperbolas with their centers on the extension of the diagonal of the square which they intersect. Multiplying out the expression x A atomic fraction of A = y = ------ where x is the weight fraction of A, and A and B are atomic weights, we get xy+A/By- A/Bxy=x Upon rotating and translating axes and avoiding imaginaries, it is found that the angle of rotation is —45°, the origin moves upv2/2 units andv2/2(A/B+1/A/B-1) units to the right, and the standard form is Thus the curves are equilateral hyperbolas, their centers are units away from their intersection with

Jan 1, 1950

By Charles A. Ashburner

[The statistics contained in this paper were collected for the United States Geological Survey and communicated to the Institute, by permission, prior to their publication in the report on the Mineral Statistics of the United States for 1887.1 The total coal-production of Alabama in 1887 was about 1,950,000 short tons, the spot-value of which, at the mines, was $2,535,000. The coal-regions of the State lie in the extreme southern part of the Appalachian coal-field, the northern part of which lies along the western New York-Pennsylvania State line; between these limits, New York on the north and Alabama on the south, portions of the

Jan 1, 1889

By R. W. Raymond

THE absence of a convenient glossary of terms connected with mining and metallurgy has long been felt by the general public. It is to meet this want, not to furnish a technical manual for experts, that the following glossary has been prepared. It originated in an attempt on my part to revise for publication the manuscript of a compilation prepared from the appendix of Yale's work on Mining Titles and one or two other sources, to serve as an appendix to a new work on mining law, about to be published by Mr. H. N. Copp, of Washington, D. C. This revision soon assumed, contrary to my original intention, the proportions of a reconstruction; and with the consent of Mr. Copp, and for the purpose of receiving from my fellow-members valuable aid, I presented my still incomplete work as a paper at the Lake Superior meeting of the Institute, inviting from any quarter suggestions of new terms or better definitions to be incorporated in the glossary before its final publication. This invitation was so widely and generously responded to, that I cannot undertake to make in this place individual acknowledgments to those members of the Institute, and professional colleagues outside of it, who have favored me with assistance and advice. The labor bestowed upon this paper since its presentation at the Lake Superior meeting has considerably exceeded that of its first preparation, as may be inferred from its great increase in length, as well as the numerous alterations which it has undergone. It could certainly be still further enlarged and improved; but I think a comparison of it with any of the glossaries of the same class now in print will show, at least, that it is an advance upon what has hitherto been accomplished. 1 shall be grateful, however, for further criticisms and suggestions; and I purpose at some future time to incorporate in a supplementary paper the results of such additional collections or corrections as I may obtain. To avoid too great prolixity, I adopted at the outset the following general principles: 1. To include the most important technical words and phrases used by American miners and metallurgists, or occurring in English books and periodicals.

Jan 1, 1881

By G. W. Imholz

A number of interesting wells were drilled in north central Texas during 1940. The Shell Oil Company's Smith well in scc. 143, block I, H. and T. C. survey, Stonewall County, was completed for an initial production of 581 bbl. per day from the Mississippian limestone, with a total depth of 6065 ft. The same company's Patterson well, sec. 393, block D. H. and T. C. survey, Stonewall County, tested the Ellenburger limestone and was abandoned as a dry hole with a total depth of 6760 feet. In Nolan County the Tex-Harvey Oil Co. drilled a well in sec. 43, near the Tipton well, which was completed as a small producer in the Strawn section. The Tex-Harvey well tested this producing horizon but was abandoned as a dry hole with a total depth of 5210 feet. The Montour-Haggart well, sec. 184, block 2, H. and T. C. survey, Fisher County, tested the Strawn and was abandoned with a total depth of 5664 feet. The Georgian Oil Company's Blach, sec. 309, T. R. and L.. Shackelford County, encountered the top of the Ellenburger limestone at 4725 ft. After being plugged back to 3915 It. from a total depth of 4825 ft., the well tested 10 bbl, of oil per day and 300 bbl. of water. The W. I. Sothern No. 2 Carlisle well in sec. 293 was deepened to the Cambrian. The top of the Ellenburger was encountered at 6540 fcet. A wildcat well in Fisher County, the E. A. Stephenson-Maberry, apparently opened a new pool when the well encountered sand from 3298 lo 3302 ft. and was completed for 50 bbl. per day in the Cook sand horizon. In Jones County, the King Oil Company's Olsen well, sec. 158, B. B. B. and C. survey, extended the Avoca-Olander pool. The well was completed for 263 bbl. in 8 1/2 hr. from the Palo Pinto limestone, from 3298 to 3302 ft. Ungren-Frazier extended the Akard pool with No. I Akard, in the D. 'T. Bruce survey. The well was completed for 83 bbl. per day from the Cook sand, encountered from 2109 to 2126 feet.

Jan 1, 1941

By G. W. Imholz

A number of interesting wells were drilled in north central Texas during 1940. The Shell Oil Company's Smith well in scc. 143, block I, H. and T. C. survey, Stonewall County, was completed for an initial production of 581 bbl. per day from the Mississippian limestone, with a total depth of 6065 ft. The same company's Patterson well, sec. 393, block D. H. and T. C. survey, Stonewall County, tested the Ellenburger limestone and was abandoned as a dry hole with a total depth of 6760 feet. In Nolan County the Tex-Harvey Oil Co. drilled a well in sec. 43, near the Tipton well, which was completed as a small producer in the Strawn section. The Tex-Harvey well tested this producing horizon but was abandoned as a dry hole with a total depth of 5210 feet. The Montour-Haggart well, sec. 184, block 2, H. and T. C. survey, Fisher County, tested the Strawn and was abandoned with a total depth of 5664 feet. The Georgian Oil Company's Blach, sec. 309, T. R. and L.. Shackelford County, encountered the top of the Ellenburger limestone at 4725 ft. After being plugged back to 3915 It. from a total depth of 4825 ft., the well tested 10 bbl, of oil per day and 300 bbl. of water. The W. I. Sothern No. 2 Carlisle well in sec. 293 was deepened to the Cambrian. The top of the Ellenburger was encountered at 6540 fcet. A wildcat well in Fisher County, the E. A. Stephenson-Maberry, apparently opened a new pool when the well encountered sand from 3298 lo 3302 ft. and was completed for 50 bbl. per day in the Cook sand horizon. In Jones County, the King Oil Company's Olsen well, sec. 158, B. B. B. and C. survey, extended the Avoca-Olander pool. The well was completed for 263 bbl. in 8 1/2 hr. from the Palo Pinto limestone, from 3298 to 3302 ft. Ungren-Frazier extended the Akard pool with No. I Akard, in the D. 'T. Bruce survey. The well was completed for 83 bbl. per day from the Cook sand, encountered from 2109 to 2126 feet.

Jan 1, 1941

By James Barr

WHEN phosphate mining operations first commenced in Tennessee the loss of both high- and low-grade material was large, because of the crude hand methods employed. Practically all rock smaller than 2 in. was thrown back into the pits and covered with the overburden of subsequent openings. With the advent of mechanical washers and other mining machinery, together with the abolishing of the contract system, the waste has been steadily diminished, until at present only the finest sand is being rejected; and even this is not lost, for in the majority of cases the water, slime, and sand from the washers are run into large settling ponds where practically all of the phosphate-bearing material is caught and stored for future use, or until it is profitable to ship lower grades. The latest equipment used to recover the fine and lower-grade phosphate sand includes Dorr thickeners, settling tanks, Dorr classifiers and settling ponds served by locomotive cranes with clam-shell buckets, making it possible to save material averaging as fine as 200 mesh. To attempt saving finer material would necessitate a different type of drier, which might be patterned after the multiple-deck roasters. The present tailing runs from 15 to 25 per cent. of available phosphate, which, however, as mentioned before, does not represent a total loss to possible future operations. The demand of the consumer is the greatest factor in regulating the recovery at present. In the mining of blue rock, which does not require washing treatment, the main waste material is the capping of low-grade kidney forma-tion, generally used for backfilling of the rooms. By reason of the introduction of improved methods in the early stages and the re-mining of territory skimmed over at the start, at the present time the net result of all operations is a comparatively small loss.

Jan 2, 1916

By R. Q. Shotts

Data are presented which show that fractions of varying densities from the same coals are oxidized at different rates by nitric acid. From oxidation data, the approximate quantity of "bright" and "dull" components may be calculated. Definite relationships between oxidation rate and rank are shown for density fractions from at least two bituminous coals. IN 1945, the Alabama State Mine Experiment Station initiated a program on the determination of fusain in certain coals of the state.1 Because of the lack of equipment and personnel necessary for microscopic examination, the chemical method2 was used exclusively. During studies of the distribution of fusain in fractions of various sizes and densities on a medium volatile coal, the author noted a higher rate of oxidation of the nonfusain part of the coal in the lower density fractions and the difference in rate became more marked the shorter the oxidation period used. Since durain and other "dull" components of coal have been reported3,4,5 to have higher densities than vitrain and the bright components, it appeared probable that the observed differences in rates of oxidation in the different density fractions were due to variations in petro-graphic composition. Such effects have been noticed by other workers.2,3 In order to obtain further evidence on this point, several Alabama coals of different rank have been separated into three or more fractions on the basis of density and their rates of oxidation determined, using the procedure specified for the determination of fusain, except that measurements were made at short time intervals as well as for the longer periods specified in the regular procedure. Significant differences in the rates of oxidation of the nonfusain part of the various fractions have been observed, and it is believed that studies of this type may make possible the identification of individual petrographic components or lead to methods for their semiquan-titative estimation. Properties of the Coals: Analyses and some properties of the whole coals studied are given in table I. The range in rank of the coals is not the widest possible within the state, but samples of the low volatile coals that occur in thin beds in the northeastern part of the state, were unavailable. The Clements bed is not, at present, considered workable. The coal is of medium volatile rank, quite friable, and very strongly swelling. Analyses of different size fractions show that the larger sizes are of higher rank than the smaller ones. Material passing the No. 50 sieve (all sieve sizes refer to the U. S. Standard Series) is close to high volatile A in rank, except for the size passing a No. 200 sieve, in which fusain is partially concentrated. Because of the variation in rank of the sizes of Clements coal, oxidation studies were made of two widely different size ranges. The + 1-in. material was crushed on rolls to about 1/8 in. and separated into five fractions by float-and-sink treatment in a benzene-carbon tetrachloride mixture. The — No. 4 + No. 8 and the — No. 4 + No. 50 size ranges tested overlap but the latter size was studied last with the expectation that it would include more oxidizable material than the first size. This proved not to be the case. Yields and properties of the specific gravity fractions oxidized are shown in table II. Milldale bed coal probably represents, as nearly as it is possible to do so, the "average" coal of the state. The material passing a No. 4 sieve was the only size range oxidized. It was divided into four specific gravity fractions. As in every case the heaviest fraction, which was essentially rock, was discarded. The Black Creek is the most extensive in area of

Jan 1, 1951

By R. Q. Shotts

Data are presented which show that fractions of varying densities from the same coals are oxidized at different rates by nitric acid. From oxidation data, the approximate quantity of "bright" and "dull" components may be calculated. Definite relationships between oxidation rate and rank are shown for density fractions from at least two bituminous coals. IN 1945, the Alabama State Mine Experiment Station initiated a program on the determination of fusain in certain coals of the state.1 Because of the lack of equipment and personnel necessary for microscopic examination, the chemical method2 was used exclusively. During studies of the distribution of fusain in fractions of various sizes and densities on a medium volatile coal, the author noted a higher rate of oxidation of the nonfusain part of the coal in the lower density fractions and the difference in rate became more marked the shorter the oxidation period used. Since durain and other "dull" components of coal have been reported3,4,5 to have higher densities than vitrain and the bright components, it appeared probable that the observed differences in rates of oxidation in the different density fractions were due to variations in petro-graphic composition. Such effects have been noticed by other workers.2,3 In order to obtain further evidence on this point, several Alabama coals of different rank have been separated into three or more fractions on the basis of density and their rates of oxidation determined, using the procedure specified for the determination of fusain, except that measurements were made at short time intervals as well as for the longer periods specified in the regular procedure. Significant differences in the rates of oxidation of the nonfusain part of the various fractions have been observed, and it is believed that studies of this type may make possible the identification of individual petrographic components or lead to methods for their semiquan-titative estimation. Properties of the Coals: Analyses and some properties of the whole coals studied are given in table I. The range in rank of the coals is not the widest possible within the state, but samples of the low volatile coals that occur in thin beds in the northeastern part of the state, were unavailable. The Clements bed is not, at present, considered workable. The coal is of medium volatile rank, quite friable, and very strongly swelling. Analyses of different size fractions show that the larger sizes are of higher rank than the smaller ones. Material passing the No. 50 sieve (all sieve sizes refer to the U. S. Standard Series) is close to high volatile A in rank, except for the size passing a No. 200 sieve, in which fusain is partially concentrated. Because of the variation in rank of the sizes of Clements coal, oxidation studies were made of two widely different size ranges. The + 1-in. material was crushed on rolls to about 1/8 in. and separated into five fractions by float-and-sink treatment in a benzene-carbon tetrachloride mixture. The — No. 4 + No. 8 and the — No. 4 + No. 50 size ranges tested overlap but the latter size was studied last with the expectation that it would include more oxidizable material than the first size. This proved not to be the case. Yields and properties of the specific gravity fractions oxidized are shown in table II. Milldale bed coal probably represents, as nearly as it is possible to do so, the "average" coal of the state. The material passing a No. 4 sieve was the only size range oxidized. It was divided into four specific gravity fractions. As in every case the heaviest fraction, which was essentially rock, was discarded. The Black Creek is the most extensive in area of

Jan 1, 1951

By H. S. Price, J. C. Cavendish, R. S. Varga

This paper presents a new technique for solving some of the partial differential equations that are commonly used in simulating reservoir performance. The results of applying this technique to a simple problem show that one obtains accurate pressure values near wells, as well as accurate pressure pdients, which can be explicitly calculated. The method is completely rigorous in that convergence of the discrete numerical solution to the continuous solution for both pressure and pressure gradient is established. High-order, piecewise-polynomial approximations are used near the wells where pressure gradients are steep, while low-order, piecewise-polynomial approximations are used elsewhere to reduce greatly the calculation time. This combination is shown to give a uniformly good approximation to the solution. These approximations, obtained by using a Galerkin process with suitable Hermite subspaces, are shown to be theoretically and numerically superior to the usual approximations obtained from standard finite-difference techniques. Not only are much greater accuracies obtained, but computer times are also greatly reduced. The application of this technique to multiphase flow problems (e.g., single well coning problems) would have considerable practical interest, but such extensions of this technique with full mathematical rigor have not been made as yet. However, the numerical methods presented here are general, and in principle extend to multidimensional, multiphase flow. Moreover, the preliminary results given in this paper are sufficiently encouraging that we feel the effort in attempting these extensions is justified. INTRODUCTION The problem of obtaining accurate pressure distributions and pressure gradients around wells is of considerable importance in the numerical simulation of reservoir performance. The most common approach to solving this problem is to use finite difference techniques (see McCarty and Barfield9 or Peaceman and Rachfordl0). This approach, however, has many disadvantages, the major one being that many grid points are generally necessary for accurately describing the pressure distribution and the pressure gradient around wells. This need for a fine grid results in large computer times and often in prohibitively high costs. Besides investigating the method of finite differences, some authors, such as Welge and weber17 and Roper, Merchant and Duvall,13 have considered a combination of analytical and numerical techniques with some success. These approaches, however, are all nonrigorous and quite often cannot even be applied. In this paper, we present a numerical formulation of high-order accuracy, based on the Galerkin method, for solving this problem. We treat here only the partial differential equation that describes steady-state, single-phase flow. However, the methods presented are general and in principle extend to multidimensional, multiphase flow. Specifically we treat special cases of the problem in two dimensions described by: where G is a rectangle (with sides parallel to the coordinate axis) with boundary ?G, ?/?n denotes the outward normal, and y and B are non-negative constants such that y + B > 0.

Jan 1, 1970

By D. F. Botkin, B. H. Sage, W. N. Lacey

Joule-THomson coefficients for two natural gases were determined at pressures up to 600 lb. per sq. in. throughout the temperature interval between 70" and 310°F. From these primary data and available information relating to the isobaric heat capacities of the components at infinite volume, the heat capacities of these gases were computed throughout the above-mentioned range of pressures and temperatures. The enthalpies of the gases were computed as a function of state and the results compared with values obtained by several methods of prediction currently available. Table i .—Composition of Gas Samples Components Gas A Gas B Carbon dioxide................ 0.0090a 0 .042 0 Methane...................... 0.8255 0.8385 Ethane.......................0.0901 0 .0637 Propane....................... 0.0462 0.0374 Isobutane..................... 0.0074 0.0039 n-butane................ ...... 0. 0126 0 .0095 Isopentane.................... 0.0032 0.0016 n-pentane..................... 0.0022 0.0011 Hexanes and Heavier........... 0.003& 0.0023 Experimentally determined Joule-Thom. son coefficients for natural gases afford a satisfactory means of checking the accuracy of prediction of their thermodynamic properties from the behavior of the components in the pure state and in binary mixtures. Relatively small samples of these natural gases were available, together with their analyses, and the Joule-Thomson coeffi- The Joule-Thomson coefficients were determined by measuring the change in temperature resulting from the passage of the gas through a porous thimble with a known pressure difference and under such conditions that the process was substantially isonthalpic. The details of the apparatus employed for this purpose have been described.' It is believed that the changes in temperature and pressure were ascertained with an uncertainty of not more than 0.3 per cent. However, as a result of deviations from steady flow, it is probable that uncertainties as large as 2 per cent may exist in the measured Joule-Thomson coefficient. The gases utilized in this work were taken from high-pressure separators and were dried prior to use by passage over calcium chloride at pressures in excess of 300 lb. per sq. in. The gases were subjected to the conventional fractionation and Orsat analyses. The results are recorded in Table I. The composition is typical of gases from such sources, with the possible exception of the presence of significant quantities of carbon dioxide in each of the samples. The experimental results obtained for the two natural gases are graphically Portrayed in Figs. I and 2. The experimental

Jan 1, 1943

By W. N. Lacey, D. F. Botkin, B. H. Sage

Joule-THomson coefficients for two natural gases were determined at pressures up to 600 lb. per sq. in. throughout the temperature interval between 70" and 310°F. From these primary data and available information relating to the isobaric heat capacities of the components at infinite volume, the heat capacities of these gases were computed throughout the above-mentioned range of pressures and temperatures. The enthalpies of the gases were computed as a function of state and the results compared with values obtained by several methods of prediction currently available. Table i .—Composition of Gas Samples Components Gas A Gas B Carbon dioxide................ 0.0090a 0 .042 0 Methane...................... 0.8255 0.8385 Ethane.......................0.0901 0 .0637 Propane....................... 0.0462 0.0374 Isobutane..................... 0.0074 0.0039 n-butane................ ...... 0. 0126 0 .0095 Isopentane.................... 0.0032 0.0016 n-pentane..................... 0.0022 0.0011 Hexanes and Heavier........... 0.003& 0.0023 Experimentally determined Joule-Thom. son coefficients for natural gases afford a satisfactory means of checking the accuracy of prediction of their thermodynamic properties from the behavior of the components in the pure state and in binary mixtures. Relatively small samples of these natural gases were available, together with their analyses, and the Joule-Thomson coeffi- The Joule-Thomson coefficients were determined by measuring the change in temperature resulting from the passage of the gas through a porous thimble with a known pressure difference and under such conditions that the process was substantially isonthalpic. The details of the apparatus employed for this purpose have been described.' It is believed that the changes in temperature and pressure were ascertained with an uncertainty of not more than 0.3 per cent. However, as a result of deviations from steady flow, it is probable that uncertainties as large as 2 per cent may exist in the measured Joule-Thomson coefficient. The gases utilized in this work were taken from high-pressure separators and were dried prior to use by passage over calcium chloride at pressures in excess of 300 lb. per sq. in. The gases were subjected to the conventional fractionation and Orsat analyses. The results are recorded in Table I. The composition is typical of gases from such sources, with the possible exception of the presence of significant quantities of carbon dioxide in each of the samples. The experimental results obtained for the two natural gases are graphically Portrayed in Figs. I and 2. The experimental

Jan 1, 1943

By C. C. Harris

The Gaudin-Meloyl equation for the size distribution of fragments resulting from single fracture is where y is the mass fraction of material smaller than size x, and x, and r are parameters to be determined from the experimental data. In physical terms, r is associated with the number of active flaws in a particle of characteristic dimension xo . The special attribute of this equation is its emphasis on the coarse size region of a distribution. There are various procedures2-5 for obtaining the parameters in Eq. 1, but a simple graphical method is awaited. This situation contrasts sharply with that in the cases of the familiar Gates-Gaudin-Schuhmann and Rosin-Rammler equations.6 The purpose of this note is to present a method based on a procedure7 which has been successful in several other applications.8-13

Jan 1, 1967