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When the writer first began his search for the early history of coal he was amazed at the paucity of information in literature about it, and while after six years many of the reasons for such a scarcity are understood, there are still many cases, even within the last two centuries, when one who can appreciate the tremendous part coal has played in the development of modern times, finds it hard to realize how little attention was paid to this material in those early clays. Occasionally a traveller or observer is found who foresaw how valuable coal was to be when industries were developed, but these were few and to most of those recording its occurrence it was just another mineral. George Washington was farsighted in his view of the development of this country and the need for means of transportation across the mountain barrier, but it was at least sixteen years after he must first have known of coal before he made any reference to it in his journals. He did, however, knowingly or not, select some valuable coal properties in the lands lie obtained in the West. This was then almost entirely an agricultural country, and what industries there were found a great abundance of wood fuel within easy access, there were no steam plants, and all iron was made with charcoal; in fact, the "captive mines" of the iron industry then were large timber "plantations," and when these were exhausted the furnace usually was abandoned and another one built elsewhere, as transportation of charcoal was quite expensive. Along the seaboard the cities and industries began to import coal from England and Nova Scotia early in the eighteenth century, but until the war of the Revolution began the total quantity of coal used yearly in this continent did not exceed nine thousand tons. In 1800 only two places, Pittsburgh and Richmond, Virginia, were using coal to any extent for domestic purposes and it was much later. than this that the amount of coal used in Philadelphia, New fork, and Boston exceeded that of wood. Practically all of the early travellers and writers mentioning coal are noted in the following pages. Several Englishmen who were evidently familiar with its use and value at home, mention its presence as being of great future promise to the young nation, but to nearly all it was more or less of a curiosity and the smoke caused by its use an abomination, and it

Jan 1, 1942

By Raymond D. Sloan

Retaining third place in crude-oil production among the nation's oil-producing states, Oklahoma's output in 1942 totaled 137,792,000 bbl., a decline of 9.4 per cent from the previous year's total of 152,117,000 bbl. Production declined from an average of 403,000 bbl. daily in January 1942 to an average of 355,000 bbl. during December, a reduction of 48,000 bbl. daily (11.9 per cent) during the year. At the end of 1942 it would appear inevitable that the downward trend in production will continue in 1953 unless halted in the immediate future by greater than normal discoveries and development. To Jan. I, 1943, Oklahoma has produced 5,067,013,000 bbl. oil crude oil. Development and Exploration Development dropped abruptly in 1942, reflecting the lack of any sizable discoveries and the effect of the provisions of Federal Well Spacing Order M-68, which became effective in December 1941. In all, 1210 wells were drilled in 1942. This represents a decrease of 42.7 per cent from the 1941 total of 2110. Of the total wells completed, 553 (45.7 per cent) were oil wells with an average initial production of 443 bbl.; 102 (8.4 per cent) were gas wells with an average initial of 3,359,000 cu. ft.; and 555 (45.9 per cent) were dry. Although the number of completions declined sharply, the total of 320 wildcats completed (26.4 per cent of all wells) repre-sents a decrease of only 2.7 per cent from the previous year's figure of 329. Of the wildcats drilled, 44 (13.8 per cent) were oil wells, 13 (4.0 per cent) were gas wells, and 263 (82.2 per cent) were recorded as failures. Reconditioning of wells throughout the state resulted in a total recompletion of 355 wells. Of these, 234 were oil wells with a combined initial production of 96,808 bbl., 32 were gas wells with a total initial of 381,488,000 cu. ft., and 89 were abandoned. None of the 26 pools found in 1942 has developed into a major discovery. The Pauls Valley pool, Garvin County, is the most outstanding. Since its discovery in April, 14 wells with an average initial of 1898 bbl. have produced 803,000 bbl. of 42' gravity oil from the Bromide zone. Development in this pool is believed to be almost completed. Other of the more important discoveries are the East Watchorn pool, Pawnee County; Guthrie Townsite and West Navina, Logan County; Brooksville and Macomb, Pottawatomie County, and the Liberty and Northeast Lucien discoveries in Noble county. The East Watchorn pool, at the close of the year, had 14 completed oil wells with an average initial of 989 bbl. from the Wilcox sand at 3930 it.; Guthrie Townsite, one well with an initial of 840 bbl. from dolomite at 5600 It.; West Navina, six wells with an average initial of 284 bbl. in the Lay ton sand at 5050 ft., Brooksville, eight wells in the Hunton at 4800 ft. with an average initial 01 355 bbl.; Macomb, one well with an initial of 160 bbl. in the IIunton at 4700 ft.; the Liberty pool, one well with an initial of 1268 bbl. in the second Wilcox at 4500 ft., and two wells in the Tonkawa sand at 2500 ft., with an average initial of 230 bbl. In the Northeast Lucien pool, four wells were completed in the Wilcox at 5380 ft. for an average initial of 1164 bbl., and one well was completed in the Viola lime at 5255 ft. for an initial of 55 barrels.

Jan 1, 1943

By Raymond D. Sloan

Retaining third place in crude-oil production among the nation's oil-producing states, Oklahoma's output in 1942 totaled 137,792,000 bbl., a decline of 9.4 per cent from the previous year's total of 152,117,000 bbl. Production declined from an average of 403,000 bbl. daily in January 1942 to an average of 355,000 bbl. during December, a reduction of 48,000 bbl. daily (11.9 per cent) during the year. At the end of 1942 it would appear inevitable that the downward trend in production will continue in 1953 unless halted in the immediate future by greater than normal discoveries and development. To Jan. I, 1943, Oklahoma has produced 5,067,013,000 bbl. oil crude oil. Development and Exploration Development dropped abruptly in 1942, reflecting the lack of any sizable discoveries and the effect of the provisions of Federal Well Spacing Order M-68, which became effective in December 1941. In all, 1210 wells were drilled in 1942. This represents a decrease of 42.7 per cent from the 1941 total of 2110. Of the total wells completed, 553 (45.7 per cent) were oil wells with an average initial production of 443 bbl.; 102 (8.4 per cent) were gas wells with an average initial of 3,359,000 cu. ft.; and 555 (45.9 per cent) were dry. Although the number of completions declined sharply, the total of 320 wildcats completed (26.4 per cent of all wells) repre-sents a decrease of only 2.7 per cent from the previous year's figure of 329. Of the wildcats drilled, 44 (13.8 per cent) were oil wells, 13 (4.0 per cent) were gas wells, and 263 (82.2 per cent) were recorded as failures. Reconditioning of wells throughout the state resulted in a total recompletion of 355 wells. Of these, 234 were oil wells with a combined initial production of 96,808 bbl., 32 were gas wells with a total initial of 381,488,000 cu. ft., and 89 were abandoned. None of the 26 pools found in 1942 has developed into a major discovery. The Pauls Valley pool, Garvin County, is the most outstanding. Since its discovery in April, 14 wells with an average initial of 1898 bbl. have produced 803,000 bbl. of 42' gravity oil from the Bromide zone. Development in this pool is believed to be almost completed. Other of the more important discoveries are the East Watchorn pool, Pawnee County; Guthrie Townsite and West Navina, Logan County; Brooksville and Macomb, Pottawatomie County, and the Liberty and Northeast Lucien discoveries in Noble county. The East Watchorn pool, at the close of the year, had 14 completed oil wells with an average initial of 989 bbl. from the Wilcox sand at 3930 it.; Guthrie Townsite, one well with an initial of 840 bbl. from dolomite at 5600 It.; West Navina, six wells with an average initial of 284 bbl. in the Lay ton sand at 5050 ft., Brooksville, eight wells in the Hunton at 4800 ft. with an average initial 01 355 bbl.; Macomb, one well with an initial of 160 bbl. in the IIunton at 4700 ft.; the Liberty pool, one well with an initial of 1268 bbl. in the second Wilcox at 4500 ft., and two wells in the Tonkawa sand at 2500 ft., with an average initial of 230 bbl. In the Northeast Lucien pool, four wells were completed in the Wilcox at 5380 ft. for an average initial of 1164 bbl., and one well was completed in the Viola lime at 5255 ft. for an initial of 55 barrels.

Jan 1, 1943

By H. C. LIVINGSTON

At the Hanna No. 4-A mine of The Union Pacific Coal Co. a new system of trackless mining is being utilized to extract a 26-ft coal seam. By using shuttle cars and a conveyor belt for haulage in the rooms and panel entries instead of pit cars and panel hoist a saving of 12 cents per ton is expected. Mining is conducted in a 26-ft coal seam laid down on a synclinal structure with active workings on a pitch of approximately ten to twelve degrees. The coal seam is interbedded between a shale bottom and sand- stone top. The coal is friable, high in moisture, and subject to spontaneous combustion. The mine is rated gassy by the State Coal Mine Inspection Department. Mining is conducted at the present time by unbalanced rope haulage an main slopes spaced on approximate 4300-ft centers with the three-entry system driven to boundary lines, strike entries being turned on approximate 1300-ft centers. Panels are driven to the rise between entries at approximately 750-ft intervals with panel rooms driven on the strike 500 to 600 ft long, leaving 150 ft of barrier pillar between each block of panel rooms.

Jan 1, 1949

By J. J. Calaman, D. H. Fleming

DURING 1950 the jet-piercing process was used commercially in the piercing of primary blast-holes in magnetic taconite at the preliminary taconite plant of .the Erie Mining Co., Aurora, Minn. The Erie Mining Co. purchased a jet-piercing machine and associated equipment in 1949, and the machine has been in operation since its installation in the summer of that year. An overall view of the pit with the JPM-1 jet-piercing machine in operation is shown in Fig. 1. During three months of 1949 and continuously since February 1950, production piercing took place under all pit conditions. By the end of October 1950, a total of 15,000 linear ft of hole had been pierced in an open pit handling an average of 1200 to 1800 tons of crude a day in one 8-hr shift. While it is recognized that this output does not approach the millions of tons a year planned for the developing Minnesota taconite projects, the machine as a unit has been operating under conditions probably more adverse than those that eventually will be encountered in the large operations. This pilot operation has permitted evaluation of the piercing problem in the full-scale taconite plant. This paper describes jet-piercing process funda- mentals, important features of the latest jet-piercing burners and machine, actual piercing results obtained, and new developments that give promise of materially increasing overall process efficiency. To produce the blasthole, jet-piercing utilizes thermal energy, as contrasted with the application of mechanical energy in churn drills and jackham-mers. The heart of the process may be termed a tailored flame produced by a rocket-type burner, thermodynamically similar in every respect to that of the giant rockets being developed for military purposes. The heat release in the combustion chamber of the burner is about 50x10' Btu per cu ft per hr as compared with 5x10' for most modern steam generators.* Combustion of liquid petroleum fuels (kerosine, diesel oil, or No. 2 fuel oil) with gaseous oxygen in the burner chamber at pressures of 100 to 200 psi results in temperatures of about 4300°F. Expansion of the hot combustion gases through divergent nozzles produces high-temperature supersonic jets having measured velocities of about 6000 fps. Impinging the flame jets on rock causes a thin surface layer to expand and break away from the base as a result of the thermally induced stresses. This spalling action is aided further in chert and quartzite by the 0.82 pct volume change resulting from the 6 to p quartz inversion at 1066"F.t The dynamic action of the jets whisks the spalled rock

Jan 1, 1952

By Laurance Reid

HIGH compression ratios, resulting from high injection pressures and relatively low recovery process pressures, constitute a major problem, which has confronted those engaged in gas recycling for condensate production since the beginning of that practice. Despite the numerous process developments and improvements, no entirely satisfactory solution for this prob-lem has been presented to date. Often, where the residue gas from the recovery process must be recompressed for subsurface injection, there is a substantial difference between the required injection pressure and the plant-operating pressure required to produce maximum recovery of condensate. These limitations result in high compression ratios, which, in turn, neces-sitate excessive compressor investment and operating cost. As an alternative, the operating pressure may be increased in order to lessen the compressor requirements but such a saving often is purchased at the expense of decreased condensate recovery, caused by operation at the higher pressure. Regardless of the choice, the net result is a diminished return on the capital invested in the project. The goal of future development in this field must be the complete recovery of all valuable hydrocarbon components in the reservoir fluid at pressures that, regarded as compressor suction pressure, will require minimum compressor horsepower to inject the residue gas into the formation. A com-pression ratio of 1.5 has been established as an optimum for modern compressor equipment." Therefore, in order to con-form to this optimum condition, a 3000-lb. injection pressure would require that the condensate recovery process be operated at 2000 lb. per sq. inch.

Jan 1, 1940

By Carl Scholz

FROM the engineer's standpoint, labor organizations are of interest in so far as they 'affect efficiency, maximum production and unit cost, and in this respect the earlier labor organizations' which existed in the age of the Guilds were ideal, inasmuch as they stood ' for competency of the apprentice and close cooperation ' between employers and employees. In later years the tendencies of the labor organizations have gone in the opposite direction and, instead of cooperating 'with the engineer, they usually oppose him on the mistaken theory, that labor-saving devices reduce forces, and costs; in this respect, the united Mine Workers of America have been particularly active and, to a very great extent, successful.

Jan 1, 1921

By J. Campbell

The negative pressure developed within a solidifying sphere of pure iron is investigated theoretically assuming an elastic-plastic model. The maximum hydrostatic tension attainable is shown to be an order of magnitude smaller than that required for the homogeneous muclealion of pores in the liquid cove, and four orders of magnilude smaller than that predicted from) a rigid shell model. It is well-known that liquids can withstand large hydrostatic tensile stresses, or negative pressures. The various experimental investigations of the tensile strengths (often called the fracture pressures) of liquids are reviewed by Dean,1 and the theoretical attempts at estimating fracture pressures are critically assessed by wakeshima.2 Using Fisher's3 quation, the fracture pressure of pure liquid iron is about -70,000 atm, which may be too large by as much as a factor of 4, but is certainly correct to within an order of magnitude.' In view of the great importance of the problem of the nucleation of shrinkage cavities in castings it is of interest to determine exactly what tensile stresses can exist in the residual liquid in a solidifying casting; it has often been assumed that, because of the very low strengths of solid metals near their melting points, no interior stresses are developed at all. Nussey4 has determined theoretically the pressure in the liquid core of a solidifying metal sphere assuming that the solidified shell does not deform (i .e., is perfectly rigid), so that because of the contraction accompanying solidification (a) (about 3 pct for most metals) the progressive deposition of solid onto the inner surface of the shell causes the remaining liquid to be expanded to make up this difference in volume. This leads to a relation between the pressure P in the liquid, the initial pressure, PO, the bulk modulus of the liquid, K, and the inner and outer radii of the solid shell, o and b, respectively:

Jan 1, 1968

By John M. Kelly

New Mexico produced 39,475,388 bbl. of oil in 1944, the greatest amount in one year in the oil history of the state. This production was 593,046 bbl. or 1.25 per cent more than in 1943. New Mexico retained its position as the seventh largest oil-producing state. The maximum per well allowable on Jan. I, 1944 was 48 bbl. daily and at the end of the year it was 45 bbl. daily. Allocations as set by the New Mexico Oil Conservation Commission closely followed the recommendations made by the' Petroleum Administrator for War. The average daily pipe-line runs were within 4 per cent of the allocation. Production by counties was as fol1ows;Lea County, 33,509,548 bbl.; Eddy County, 5,504,498; Northwestern New Mexico 461, 342. Drilling activity for New Mexico in 1944 was well above that of 1943, with 362 completions. Of these, 283 were oil wells, 12 gas wells and 67 dry holes. The ratio of dry holes to producers, about I to 4, was an improvement over 1943. Wildcat drilling during 1944 was responsible for the discovery of six new fields and the extension of two present producing areas. Drilling records were established in New Mexico during 1944 with the deepest producer ever completed, the Humble Leonard Oil Company's No. I at 11,969 ft., in the Ellenburger section of Ordovician age near Jal, Lea County. The discoveries in Lea County during 1944 were as follows: West Lovington field, where Fred Turner, Jr. drilled his No. I State B .in C SE SW sec. 4-17-36 and completed it for 122 bbl. of oil in 8 1/2 hr., in the San Andreas section of Permian age. The Tonto field, where the T-exas Company completed its No. I Baskin at a total depth of 3586 ft. in Seven Rivers lime of Permian age, with an initial production of 254 bbl. of oil in 21 hours. The Drinkard area, where the Gulf Oil Corporation's Drinkard No. I flowed 782 bbl. of oil in 14 hr. from the Yeso section of lower Permian age, thus opening the first lower Permian production in the state. The total depth of this discovery was 6508 ft. and oil was 38.8" A.P.I. gravity. The Dublin area, where the Humble Oil and Refining Co. established a drilling depth record of 11,969 ft. drilling and completing its No. I Leonard Oil Co. well in the Ellenburger lime of Ordovician age. This well flowed 221 bbl. of oil per day, of 48.9º A.P.I. gravity oil. It is in sec. 12-26-37. The new pay horizon discovery of the Continental Oil Co. in the Skaggs area, where the company completed its Skaggs B-23 No. 2 in sec. 23-20-37 for 236 bbl. of oil in 21 hr. from the Wolfcamp section of lower Permian age, at a total depth of 7725 ft. This well was drilled to granite at 10,465 ft. and plugged back to the Wolf-camp for a new pay zone completion.

Jan 1, 1945

By William P. Blake

THE phenomena of concentric arrangement of minerals in rock-masses, generally known as "orbicular structure," have of late received much attention from investigators. Lawson, of the University of California, has described the orbicular gabbro at Dehesa, San Diego county, Cal. Kessler and Hamilton, of Stanford University, working independently upon the same subject, published their descriptions,2 giving also a list of many other localities in Europe and America where orbicular rocks are found, adding copious references to the literature of the subject. The orbicular diorite of the type locality in Corsica., familiar to mineralogists and petrologists under the name "Napoleonite," was described by Vogelslang in 1862.3 Chrustschoff, of St. Petersburg, has also given much atten¬tion to the subject, and is the author of a classification of the various known forms of orbicular structure.4 No complete and satisfactory explanation of the origin of or¬bicular aggregations in rocks has yet been offered. The patent fact is generally recognized that the constituent minerals have crystallized from a more or less molten or plastic magma, but why these minerals should be arranged in concentric spheres or crusts has not been clearly shown. Vogelslang, for example,

Jul 1, 1905

A SELF-RESPECTING miner doesn't wash the cuttin's off his hard hat until he quits his job but, on the other hand, he keeps his lamp clean and a "spot" focus on the work at hand; the former habit is a matter of pride and the latter serves for efficient operation. During 1949, the mining engineer got all the "wet raises" for the problem of cutting costs to meet the drop of metal prices and keeping research work up to schedule when strikes tied up his work were his headaches. We note, not without admiration, that he hasn't washed the muck off his hat in token of surrender but, on the contrary, his light shines bright on the job to be done as can be seen in the following pages. Few people have any conception of how much ore and rock have to be mined and how much sorting it takes to cull a pound of copper from a 1 % ore body. These people would be even more startled to picture the problems faced by the engineer in mining and extracting, profitably, .2 oz of gold from a ton of ore as is done at some of our lode mines. Strikers have sometimes kept our researchers from their pilot plants and research laboratories, but the end of the year shows progress in making ore out of taconite and ferruginous sandstone, with a pilot plant in operation at Aurora, Minn., and plans for one near Birmingham. Unfortunately, it looks as though the mining engineer will have to make John Doe secure in mineral resources in spite of himself. Coal for steel, power, and to warm our homes is still economically possible, in spite of Mr. Lewis, through development of mechanized tools for mining. During the year, the use of continuous mining machines has extended, transport systems are being adopted to keep the ore flowing from the face to the tune of 40 tons per man-shift. Experiments in the gasification of coal are going forward in several places and may eventually extend our fuel reserves by the addition of coal seams now too lean for mining. Liquid fuel from coal, oil shale, or natural gas will become economic when oil consumption exceeds our supply; but, at less than 30 cents a ton direct cost for mining oil shale, the engineer is almost making it competitive under present market conditions. In this age of specialists, the mining engineer is still holding his own as a broad-gauge man. As a matter of fact, he is emerging from a stage of semispecialization as a coal, nonmetallics, or metal mining man to the realization that, with mechanization, mining is fundamentally materials handling whether it is fluorspar, coal, or copper ore. From the coal business come rubber-tired mechanical loaders to the iron mines of Birmingham. Shuttle cars are also finding application in the lead mines of the Tri-State. Open-pit methods are universal. Belt conveyors, trucks, Diesels, and mobile, jumbomounted drills are finding application in all types of mining. In preparation, such methods as flotation,- heavy density, electrical, and centrifugal are finding application in coal, nonmetallics, and metals. These concepts have been recognized by the mining engineer who has kept himself informed and has been quick to seize a method, machine, or a process from another operation and, with ingenuity, applied it to his problems. This, our Annual Review issue, is written by mining engineers. In gathering these separate articles under one cover for publication, we think of it as a trrbute to the tireless energy and skill of these men. They get little of the publicity accorded physicists, medical men, labor leaders, or company executives, but they supply raw materials without which industry would die.

Jan 1, 1950

By Thunaes, Arvid

Pilot plant test work in 1942 and 1943 showed that by a combination of desliming, fine-size classification, and Sullivan deck concentration it is possible to recover heavy minerals such as cassiterite at least as fine as 10 microns in size. This appreciable improvement in gravity concentration practice has been substantiated by several full-sized plants.

Jan 1, 1950

By E. K. C. Williams, Nathaniel Arbiter

INTRODUCTION The surface processes involved in preparing ores for flotation and for operations depending on their flocculation/dispersion characteristics * vary widely in agitation dependence. Most of the reagents used for these purposes are added to grinding circuits, pump sumps, launders, or directly to flotation cells with the turbulent flow conditions usually adequate both for mixing reagents and for surface reactions without special conditioners. However, some reagent systems do require specific control of agitation intensities and reaction times, the more important of these being the following: 1. Activation of ZnS with CuSO4. With the usual conditions pH about 10, with collector added with the CuSO4, Cu 2+ is almost completely precipitated as basic compounds and as collector salt. As a result the levels of reagent in solution are extremely low which probably accounts for the need for separate conditioning. The agitation intensities are at about the 0.01 HP/ton level.** 2. Flocculation with natural or synthetic polymers. In this case the agitation problem is two-fold; first, to insure adequate initial mixing of the viscous stock solution of the

Jan 1, 1980

By D. Harrington

ANNUAL or necessary inspections and investigations of coal mines for various purposes were made possible through the Federal Coal Mine Inspection Act of May 7, 1941, which authorized entry to the Secretary of the Interior through the Bureau of Mines. Primary object of these inspections is to obtain information pertaining to health and safety conditions. Among the purposes for which the data are to be used, are annual reports to Congress, the publication of inspection reports, and the compilation and publication of statistics. The act states that inspections and investigations shall be made by employees of the Bureau of Mines, who shall co-operate with other bureaus of the U. S. Department of the Interior, as well as with the official mine-inspection, safety cr health agencies of the several states and territories. The act specifies that a coal-mine inspector shall have "the basic qualifica-

Jan 1, 1946

By B. S. Butler

PART I SUMMARY CERTAIN relations between the formation of ore deposits and other geological processes are pretty generally accepted, namely: that many ore deposits are closely associated with igneous activity; that ore deposits accompany certain types of intrusive bodies, notably batholiths and stocks, and that they are concentrated near the tops of such bodies; that igneous activity occurs in belts of strong folding and faulting; that folding and faulting are greatest in basins of extensive sedimentation and least in areas of erosion or slight sedimentation; that areas of erosion or slight sedimentation and of heavy sedimentation persist over long periods and exert a major control over structure, igneous activity, and ore deposition; that cycles of erosion, deposition, folding and faulting, igneous activity, and ore deposition, have been repeated through geologic time resulting in rather definite periods in which metal deposits have formed. In short, ore deposition is but one phase of a series of closely related geological events. It is attempted in this chapter to point out the relations of these interreacting geologic processes to the distribution of ore deposits in the western United States. Three great periods of mineralization are recognized; pre-Cambrian, post-Jurassic, and late Cretaceous-Tertiary. In distribution the deposits of the three periods, with certain exceptions, show a concentration about two large positive areas, the Colorado plateau and the Columbia plateau, which suggests a causal relation. The most general age divisions of the rocks of the Cordilleran region of the United States are (1) pre-Cambrian, and (2) Cambrian and later rocks. The pre-Cambrian rocks are exposed mainly through the Rocky Mountain belt from the Canadian boundary southward to Arizona and westward through Arizona to southern California. They have commonly

Jan 1, 1933

By Charles H. Morgan

THE process of wire drawing depends upon the property which certain metals possess, termed ductility, 'which is defined in Brande's Dictionary of Science as a property in consequence of which metals may be drawn out at length without interrupting the continuity of their constituent parts. As defined by M. Tresca, it is the property of flowing when subjected to pressure, and is termed by him the "flow of solids," in his paper, read before the Academy of Sciences in Paris, November, 1865 * In the simple language of the wire shop, it is that quality in certain metals that permit, them to be drawn (or stretched) out through a tapering, hole in a metal block or die, the die being more dense and harder than the metal to be reduced. It is a fact well known to those skilled in the art, that to succeed in drawing iron or steel wire, it is of the utmost importance to have thorough lubrication, as a lack of it would caws abrasion of the wire, or of the walls of the tapering hole in the die or plate, and quickly put an end to the operation. In drawing coarse or large sizes of wire, say 2/10 inch diameter, the pressure upon the sides of the tapering hole, where the wire comes in contact with the die, is so great that an ordinary lubricant is squeezed out when the usual reductions in size are made, and abrasion takes place. In order to meet this difficulty, and secure proper lubrication, it has been' a common practice for years to apply a paste made of rye or wheaten flour, or lime, to the surface of the wire to be drawn, and when the paste is dry, to smear the wire with tallow or grease; the wire is then ready to be drawn, the dried paste serving to prevent the lubricant from being pressed out in the. process. Some years since, when Bessemer metal came largely into use as material for wire, "the writer found that its drawing required so much more power than iron wire, that he was led to institute a series of trials to ascertain the difference in power required. It was found that Bessemer wire required from 100 to 200 per cent. more power to make the same reduction in sizes than soft iron wire, the difference depending upon the amount of carbon and other chemical constitu- * Interesting experiments in the flow of metals have been made, by Messrs. Hoopes Townsend, of Philadelphia, in cold-punching iron, published and illustrated in the Journal of the Franklin Institute, of March, 1878, by Mr. David Townsend.

Jan 1, 1881

By H. J. Rose

Sixty-five million net tons of coal were carbonized in the by-product and beehive coke ovens1 of the United States during 1924. This tonnage represented 13.4 per cent. of the bituminous coal which was mined in that year. Table 1 shows production and disposition.2 Table 1.—Production and Disposition of Ocen Coke in 1924 By-product Beehive Total Coal charged into ovens, tons................ 49,061,339 15,914,310 64,975,649 Coke produced (exclusive of screenings and breeze), tons............................. 33,983,568 10,286,037 44,269,605 Average yield of coke, per cent ............. 69.3 6.46 68.9 Disposition of coke, per cent.: Blast furnace.......................... . . 82.6 Foundry............................... . 13.3 6.6 Domestic.............................. . 1.4 6.7 Water gas manufacture and all other uses.. 4.6 . 4.1 Cokes having somewhat different combinations of chemical and physical properties are desired for the various uses listed above, and these properties depend primarily upon the types of coal used. American coals have a wide range of purity and coking quality, and the chief subject of this paper will be the selection of coals for the manufacture of blast furnace, foundry, domestic, and water-gas coke, in by-product coke ovens. It will obviously be necessary to include a discussion of those physical and chemical characteristics that are generally considered essential or desirable for each type of coke. Suitable Coals The examination and development of new sources of coking coal are important because of the irregular and limited distribution of high-grade

Jan 1, 1927

By NEWTON B. KNOX

IN Bolivia, mining is still the principal economic activity, as it was before and during the Spanish Colonial period. Tin, tungsten, antimony, copper, lead, zinc, gold, silver, sulphur, and a little bismuth are produced. The Andes mountains are divided into two main ranges in Bolivia; the Western range marks the border with Chile and the Eastern range forms the backbone of the country; in the North it drops rather abruptly eastward, to the plains of the Beni, whereas in the South it splits and is separated from the Chaco flatlands by a series of folded mountain ranges. In general the mineral deposits are found within the Eastern range or in the hills that rise from the high plateau between the ranges - really parts of the Eastern range partly submerged by recent sediments. The mineral belt is thus over 500 miles long and about 100 miles wide and includes most of the principal centers of population and the most important means of communication. The region is mountainous and the roads are bad; furthermore labor is a serious problem, for the land is poor and the agricultural population is never far from hunger. The floating supply of miners is limited and soon exhausted in any emergency like the present.

Jan 1, 1945

By William R. Webster

I have continued the investigation of the Pottstown Iron Com pany's basic Bessemer keel plates on the line referred to in my paper of last October (Trans., xxi., 766)) and have added a study of the hardening effects of sulphur, which were not taken into account at that time. The results are so encouraging that I now give them in full. For some months we have graded all the steel at these works by the table given in my former paper, and checked the grading by the forging-tests as described in the paper of Mr. Joseph Hartshorne, read at the same meeting (Trans., xxi., 748). The steel thus graded was bloomed for the plate orders. Then one slab was rolled into a plate for the order, and a tension-test was made of this plate. By the result of this tension-test we were guided in rolling the balance of the heat. Out of several hundred heats graded in this manner, 95 per cent. met the requirements of the orders in every respect, and were accepted; but these results will no doubt be improved upon, when the influence of sulphur is also considered.. The hardening effect of sulphur seems to be about 500 pounds per each .01 per cent. of increase. In the table accompanying the pres ent paper, the ultimate strength with .06.5 per cent. sulphur agrees with the old table where sulphur was not considered; that is, for all steels with less than .065 per cent. sulphur we now get lower re sults, and for those with more sulphur, higher results. Making this allowance for sulphur, the assumed ultimate strength of a 3/8-inch plate of pure iron is reduced from 38,000 pounds per square inch to 34,750 pounds. With this as a basis, I have constructed my new table, giving each of the elements, carbon, phosphorus and manganese the same hardening effect as before, to wit : Carbon is credited with a constant effect of 800 pounds per each, 0.01 per cent. Phosphorus shows greater effect in high-carbon than in low-carbon steels. For 0.07 and 0.08 C, it has about the same effect as carbon, that is, 800 pounds for each .01 P. This increases to 1500 pounds per .01 P in 0.15 C steel, or nearly twice the effect of carbon. This

Jan 1, 1894

By Arthur L. Hawthorne

10.1-1. Relative Position of Maintenance as Compared to the Overall Mining Costs. The basic issue regarding the importance of maintenance in the modern mining industry must be faced squarely by the top manage- ment of each company before any real progress can be made in organizing a maintenance program for optimum effectiveness. Just a few decades ago the maintenance at coal mines consisted primarily of a blacksmith for sharpening picks and shoeing mules; as a result, probably less than 5%of the total mining cost went to maintenance and some 80% was operating expenses (operating labor). With each succeeding advance in equipment design towards larger, more complex, and more productive units, the pendu- lum swings the other way. As an example, haulage trucks have progressed through various stages in the past 20 years from 15-ton units to a 240-ton truck now in the "shakedown" or experimental stage. The following com- parison between 15-ton, 50-ton, and 100-ton haulage trucks clearly illus- trates this changing cost pattern in terms of percent of overall costs for running each size unit. [Maintenance 24% 44 % 51 % Operating labor 59 % 33 % 16% Operating supplies (fuel oil) 4 %. 4% 3% Labor burden and vac. pay 6 % 4% 3% Depreciation Total] From the preceding figures it is interesting to note that, as a rule, operat- ing costs go down as the equipment gets larger and the maintenance costs increase with the larger units. This same trend in cost variation applies to nearly all mechanical equipment used in surface mining from the large

Jan 1, 1968