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By G. B. Pryde, R. M. Magraw

In laying out a new mine, provision should be made for the ultimate recovery of as much coal in any given bed as is consistent with safety and economic mining. Though each mining district, if not each individual mine, has problems that make the adoption of any hard and fast rule impossible, certain basic principles are adapted to practically all conditions. One of the most vital is the provision for barrier pillars of ample dimensions to protect all haulage and permanent airways during the life of the property. Where conditions permit, room or butt entries should be driven on the strike or slightly to the rise, and rooms turned at right angles to these entries. The width of rooms and room pillars is governed by conditions prevailing in the mines under consideration. A safe rule is: In advancing, extract not more than 25 to 35 per cent. of the entire seam; in exceptionally thick seams, considerably less than 25 per cent. should be taken. Rooms usually vary in length from 250 to 350 ft. (76 to 106 m.) with a barrier pillar of not less than 80 ft. between the last crosscut. in rooms and the back entry of the level above. All entries, rooms, and entry-and-room crosscuts should be driven .on sights and room crosscuts should be driven at, right angles to the direction of the rooms. In mines under excessively heavy cover or where roof conditions are bad, rooms should be driven narrow and a barrier pillar left at every fifth to tenth room. This barrier should be of such dimensions that one or more rooms, with pillars of usual dimensions, may be turned through it when the barrier is no longer required. Two of the advantages of such a barrier are the protection of the panel against peaking of roof load during pillar extraction and the easy closing of the entry in case of fire. Where economic conditions permit, it is preferable to follow the retreating panel system of mining. In the case of coal that outcrops, and even in cases where no outcrop is exposed, it is preferable to commence pillar extracting on the high side of the mine. Where the retreating

Jan 1, 1922

By C. R. Boyd

The region to which I have the pleasure of calling your attention, though limited in area, is remarkable for the quantity and purity of its mineral deposits, and in these respects it would be difficult to find its equal anywhere. IRON ORES. The red and brown hematites, pipe ore, and semi-magnetites, from which is made in charcoal furnaces the highest quality of iron for car-wheels, extend through the counties of Giles, Montgomery, Pulaski, Wythe, Smyth, Washington, Bland, Tazewell, Russell, Scott, Lee, Floyd, Carroll, and Grayson, Virginia, and run over into Ashe County, North Carolina. One locality of semi-magnetite, in the centre of the great Giles County basin, has in sight, by actual measurement, 50,000 tons of ore, which, according to Prof. Fesquet, contains 69.74 per cent. of iron and no phosphorus. In the great brown-ore belt, which passes through the counties of Montgomery, Pulaski, Wythe, Smyth, and Washington, there is an extraordinary deposit of more than a million tons. A small section of this very long vein, on Cripple Creek, in the County of Wythe, yields an ore which, analyzed by Mr. James Aumann, gave the following results: Metallic iron,........58.15 Water,.........12 96 Alumina,........2.32 Silica,.........1.09 Phosphorus,.. none. At one point towards the western end of Red Land Mountain, in Pulaski County, New River section, I measured a body of ore in this belt which will yield, to a depth of 150 feet, over 8,000,000 tons, and the deposit extends far below the 150 feet measured at the upper part. Again, at Rich Hill, near the mouth of Reed Island Creek, these veins show extraordinary surface development, giving an ore of very great purity. At numerous places, also, in the counties of Giles, Bland, Tazewell, Russell, Scott, Wise, and Lee, these brown and red iron ores are exposed in such vast quantities as to baffle both description and measurement. That of Chestnut Flat, in Giles County, back or west of the Angel's Rest Mountain, is an easily reducible ore, blood-red when crushed, of which there are fully 300,000 tons in sight. Its analysis is as follows :

Jan 1, 1880

By H. J. Rahilly

Mine fires, in the Butte district, have been a source of trouble and expense for the past thirty years, for while the actual fire area in most of the mines has been comparatively small, the handling of the gas has generally been a much larger problem than the actual putting out of the fire. The chief causes of these fires have been: Defective electrical equipment, incendiarism or carelessness, and spontaneous combustion. While fires from the first two causes have been numerous, they have generally been discovered and extinguished before they became very serious. Spontaneous combustion has been the cause of most of the large fires. Sufficient heat has been generated by ground movement, high rock temperatures, and decomposition to set fire to inflammable materials (tarred ropes, canvas, dry timber, manure, and hay) left in the gobs some years ago. Also, the heat resulting from the oxidation of the fine broken sulfide ore is sometimes sufficient to set fire to the timbers. In 1906, a fire was discovered on the 1100-ft. level of the Minnie Healy mine about 400 ft. (122 m.) west of the Minnie Healy shaft, which presumably originated, in one of the upper levels, from spontaneous combustion. The fire was walled off by concrete bulkheads and a pillar of ground 100 ft. (30 m.) thick was left below and mining resumed underneath. During subsequent operations, this pillar became cracked and broken and the fire passed into the new workings. It travelled downward and spread rapidly until, in 1917, it had become necessary to wall off portions of the Tramway, Leonard, and West Colusa mines on the 1300, 1400, 1500, 1600, 1800, 1900, and 2000-ft. levels, and the tops of the 2200-ft. raises were sealed. The fire area now consists roughly of a block 1000 by 1200 ft. and from the 600-ft. to the 2200-ft. level. This block is composed largely of a series of parallel northwest-southeast nearly vertical veins and stringers that form a large orebody, with no well-defined walls but badly fractured and faulted, and known locally as "horsetail ore." These veins, or orebodies, are mined by the square-set or the rill method.

Jan 1, 1923

By Earl Oliver

The term oil property, in this discussion, includes any type of easement or grant under which petroleum might be produced; it ranges from the mere right to drill on undeveloped wildcat acreage up to a fully developed oil property. The values of an oil property, as thus defined, vary widely according to the use for which it is intended, whether it is from the viewpoint of the speculator, the fraudulent stock promoter, the refiner and pipe-line owner, or the oil producer. The market value of a property is usually a combination of some two or more of these influences, and occasionally a combination of all of them, but we prefer to treat each viewpoint as distinct from the others, allowing the reader to make his own combination in such proportions as his inclination and property seem to require. This paper will treat the subject from the viewpoint of the oil producer. However, the other influences have such bearing on the cost of property to the producer and on the price he might obtain by its sale as to warrant brief discussion of them. Speculation, particularly lease speculation, is a parasitic growth on the oil industry, healthy enough, but of no economic value. The class of property usually dealt in for this purpose is the undeveloped lease. Its speculative value may have some relation to its probable productive value, but most frequently this value is the product of temporary excitement due to local development. The lease speculator, seeking out the trend of development or securing early information regarding a proposed test or a new discovery, immediately secures leases whose market value will be increased when the existence of such development becomes more widely known. His profits are purely unearned increment. Not proposing to spend money in exploration, he can afford to compete in purchase with the operator, who, in addition to bonus paid, must spend large sums in testing out his own acreage and that of the nearby speculator as well. It has a tendency to compel unduly high bonuses. The so-called "checker-board1' system of leasing wildcat acreage by the larger companies is on the same principle of attempting to secure the

Jan 1, 1921

By H. J. Rahilly

Mine fires, in the Butte district, have been a source of trouble and expense for the past thirty years, for while the actual fire area in most of the mines has been comparatively small, the handling of the gas has generally been a much larger problem than the actual putting out of the fire. The chief causes of these fires have been: Defective electrical equipment, incendiarism or carelessness, and spontaneous combustion. While fires from the first two causes have been numerous, they have generally been discovered and extinguished before they became very serious. Spontaneous combustion has been the cause of most of the large fires. Sufficient heat has been generated by ground movement, high rock temperatures, and decomposition to set fire to inflammable materials (tarred ropes, canvas, dry timber, manure, and hay) left in the gobs some years ago. Also, the heat resulting from the oxidation of the fine broken sulfide ore is sometimes sufficient to set fire to the timbers. In 1906, a fire was discovered on the 1100-ft. level of the Minnie Healy mine about 400 ft. (122 m.) west of the Minnie Healy shaft, which presumably originated, in one of the upper levels, from spontaneous combustion. The fire was walled off by concrete bulkheads and a pillar of ground 100 ft. (30 m.) thick was left below and mining resumed underneath. During subsequent operations, this pillar became cracked and broken and the fire passed into the new workings. It travelled downward and spread rapidly until, in 1917, it had become necessary to wall off portions of the Tramway, Leonard, and West Colusa mines on the 1300, 1400, 1500, 1600, 1800, 1900, and 2000-ft. levels, and the tops of the 2200-ft. raises were sealed. The fire area now consists roughly of a block 1000 by 1200 ft. and from the 600-ft. to the 2200-ft. level. This block is composed largely of a series of parallel northwest-southeast nearly vertical veins and stringers that form a large orebody, with no well-defined walls but badly fractured and faulted, and known locally as "horsetail ore." These veins, or orebodies, are mined by the square-set or the rill method.

Jan 1, 1923

By Henry S. Mackay

The interesting paper recently submitted by Messrs. Tobelmann and Potter1 shows that chemical problems have developed which are of great interest in this new and important branch of metallurgy. Those who realize what a process of this kind really involves will agree that it deserves a better name than '(leaching process." The word leaching conveys the idea that the copper is simply leached out of the ore with acid and then precipitated on iron; the chemistry of such a process would be of little interest. As, however, during the first year's operation of this plant 24,400,532 lb. (11,067,837 kg.) or about two-thirds of the produce, was electrolytic copper, while 7,992,033 lb., or about one-third, was cement copper, it would seem more appropriate to term the process electrochemical. It further appears, from the particulars given, that efforts have been made to have the entire production in the form of electrolytic copper. This could be done if the chemistry of the problem were kept in balance, so that it would not be necessary to discard any solutions that carried copper and acid of commercial value. A process, such as that under consideration, in which the copper is precipitated from solution by electrolysis, the solvent being at the same time regenerated, is one that requires special chemical and electrochemical knowledge and experience if all the copper in solution that has been extracted from the ore is to be successfully and economically produced as electrolytic copper. The object of this paper is to discuss, from the practical and theoretical standpoints, the chemical and electrochemical problems involved in the working of a process of this kind, and which must be solved to keep it in chemical and electrochemical equilibrium. In such a process, if the chemical balance is maintained, a solution can be used alternately as a solvent for the copper in the ore and as an electrolyte of high efficiency for the precipitation of the copper. To maintain the chemical equilibrium and so attain this result, the process must be so controlled that the solu-

Jan 1, 1921

By L. C. Snider

During the past few years a number of large and highly productive oil fields have been discovered in the United States. The immediate oversupply which has resulted, together with the circumstances under which the new fields have been operated, has created exaggerated impressions of the importance and magnitude of these fields. Statements as to the many years during which individual fields could supply the entire demand of certain areas, as to the overwhelming effect of these fields on the industry, and as to their greater size compared with any of the older fields have become so common as to attract little attention. For example, East Texas is commonly considered as the "greatest oil field" and a review of the development of the field for 1931 is so headed in one of the leading trade journals.' East Texas is unquestionably a very great oil field. However, some students of the field have estimated its ultimate recovery at about one billion barrels, and the Bradford field discovered in 1875 is also estimated, by competent engineers, to have about a billion barrels still recoverable by water drive, in addition to more than 300,000,-000 bbl. it has already produced. If East Texas should produce the two or three billion barrels assigned to it by more optimistic estimators, it will, though considerably greater than Bradford, still fall far short of it in importance to the industry. A reasonable doubt also exists as to whether East Texas will exceed the Midway-Sunset field which has produced about 720,000,000 bbl. and still has important reserves. Again, in importance to the industry, Midway-Sunset has been greater than East Texas can ever be. Relative Importance of Oil Fields The principal purpose of this study is to compare, on the basis of their importance to the industry, a considerable number of the major fields which have been developed in the United States. Some remarks are also made as to the estimates of reserves in certain fields now in course of development, since the writer believes that the conditions under which these fields are operated lead to estimates of recoverable reserves which

Jan 1, 1933

This fund was established in 1929 for support of research and especially refers to non-ferrous mining and metallurgy. It is administered under the Board by a committee consisting of the President and Secretary and three members selected by the Board. HOWE MEMORIAL LECTURE The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors upon recommendation of the Iron and Steel Division. The following were the Howe lectarers for the years indicated: Albert Sauveur—1924 Bradley Stoughton—1927 John A. Mathews—1925 Henry D. Hibbard—1928 William Campbell—1926 John Howe Hall.—1929 JOINT ACTIVITIES The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers, and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Society This is a corporation organized by the American Institute of Mining Engineers, American Society of Mechanical Engineers, and the American lnstitute of Electrical Engineers, to hold the title and administer the property at 29 West 39th St. In 1916, the American Society of Civil Engineers was admitted, and each society now has an equal one-fourth interest in the ownership, occupancy, and administration of the building. . The cost of this property has been over two million dollars. A. I. M. E. representatives are: Arthur S. Dwight, John V. N. Dorr and H. A. Guess. Alfred U. Flinn, Secretary, 29 West 39th St., New York City. Engineering Foundation This is a fund established by the United Engineering Society in 1915 with a gift of $200,000 from Ambrose Swasey. Subsequent gifts had increased the fund to about $620,000 on March 1, 1929. The income of the fund is used to further research in science and engineering and to advance the profession of engineering and the good of mankind. A research project in alloys of iron is being conducted in

Jan 1, 1929

"In the spring of 1927, six members of the American Institute of Mining and Metallurgical Engineers met for dinner at the Chemists' Club in New York to discuss the possibility of setting up a committee within the Institute to further the current interest in the science of steelmaking. Attention to this subject had been crystallized by a symposium held by the Faraday Society in 1925. After a prolonged discussion, ranging from thermodynamics to slag conditioning, it was decided to approach the Institute with the request that a standing committee on "The Physical Chemistry of Steel Making" be set up. This committee proposed to promote scientific and practical papers on the subject, and was designed to cooperate with the Open Hearth Committee of the Institute in bringing scientific developments to the attention of open-hearth operators throughout the country. . . . "As the life of the [Physical Chemistry of Steelmaking] Committee lengthened and general interest in the technical phases of steelmaking grew, it .became evident that there was a distinct need for a book that might serve the open-hearth interests to better advantage than standard texts whose scope is necessarily wide and whose detailed exposition of the open-hearth process is, therefore, somewhat limited. With this thought in mind, the Committee, after some years of consideration and debate, embarked on the venture of writing a manuscript on 'Basic Open Hearth Steelmaking'." The foregoing paragraphs, taken from the introduction by C. H. Herty, Jr. to the first edition, well describe the circum- stances which led to the publication of “Basic Open Hearth Steelmaking” in the spring of 1944. The book consisted of nine- teen chapters contributed by twenty-three authors and edited by the staff of Alloys of Iron Research and T. S. Washburn, H; M. Larsen, and J. S. Marsh with Frank T. Sisco as consulting editor. The Engineering Foundation and the Open Hearth Steel Committee of the Iron and Steel Division, AIME, made financial grants; steel companies and other organizations supported the publication by contributing time and expenses of staff members in their capacity as authors or editors. The volume was sponsored by the Seeley W. Mudd Memorial Fund and appeared under the

Jan 1, 1964

JOSEPH DANIELS, Seattle; Wash. (communication to the Secretary*). Mine models are of great value to the student and to the layman in visualizing underground conditions, and, in a measure, should be just as much a part of the equipment of a mining school as sets of ore specimens, catalogs, or drawings. The chief drawback, as Professor Stock has indicated, is the time and cost of making them. The greatest good in the development of the model comes to the person who makes it, and I have often wondered whether it might not be possible to have each student make one model during his undergraduate career. At the University of Washington we have been collecting sets of mine timbers, made of 6 by 6-in. lumber, illustrating shaft, level, and stope timbering. This work has been done by freshmen. Perhaps each educational institution could specialize in the creation of a certain type of model and exchange its product for that of another school, just as we now do with ore collections. In this way we could build up good museums at a relatively low cost. JOHN R. CHAMBERLIN, New York, N. Y. (communication to the Secretary?).-The type of model described by Professor Stoek is admirably suited to exhibits of coal mining in horizontal veins, and fulfills perfectly the three purposes mentioned. As an educational illustration in colleges, especially when the students themselves build the model under the direction of their instructors, it is of the highest value; and as each condition in mining requires special methods to depict properly in a model, the student is compelled to exercise considerable inventive resource to construct a true representation, stimulating the imagination and interest in his subject. Models built for exhibits in lawsuits are usually constructed to show prominently some particular feature of vein formation or geology, or the relation of underground workings to surface property lines, and as such their use is invaluable to the successful litigant. When the litigation is ended, it is natural that the model should be relegated to the basement and frequently destroyed, as data on underground workings are often considered of a private character by the operators; and it is

Jan 10, 1917

By J. T. Duce

There were no important changes in the producing situation in Colombia in 1930, because the emergency bill passed by the Colombian Congress in 1927 is still in effect, and therefore no change has taken place in the law governing petroleum. At the close of 1930 the Colombian Congress began to consider a new petroleum bill. This measure is an improvement on the preceding bills which had been the subject of so much debate in the Congress. However, it cannot by any means be regarded as perfect, and a number of criticisms may be justly leveled at it. The most substantial one probably is that the royalties on public lands, and the taxes on private lands, while apparently low, are deliverable at seaboard, or payable based on seaboard price at the option of the government. If the government exercises its option to take the oil at the mouth of the well, the cost of the transportation figured back into oil is also deliverable to the government. This phase of the law has the effect of making seemingly low royalties a burden on the operator. The fact that taxes on private properties are deliverable in kind is also an unusual provision for which there is no good precedent. The pipe line provisions are also noteworthy, and the government has authority to fix rates and also to deny permits to construct pipe lines for reasons affecting national economy. There are also clauses enforcing unit operation on both public and private lands, and collecting a tax of 1 c. per 1000 ft. of gas wasted. It remains to be seen whether this bill will be enacted, or whether it will be substantially modified. This much may be said, however, that unless it is modified, it will defeat its own purpose; i. e., promotion of petroleum development in Colombia. Company Activities The South American Gulf Oil Co. shut down its operations during the year, and now employs only watchmen at its camps, Las Monas and El Tigre. The Standard Oil Co. of California continued operations on the Coast at Repelon and Gualapa. At the close of the year Repelon

Jan 1, 1931

By W. O. Hotchkiss

IN CONSIDERING the question of mining methods the possible rate of production deserves much more attention than it often receives. Hoover's theorem that, in order to show the greatest profit, an orebody should be worked out in the shortest practicable time, should be better known. The author recently' obtained detailed statements of costs from iron-mine superintendents of the Lake Superior district. In discussing these, the effect of rate of mining on cost of production was considered and detailed estimates were made. The methods by which these estimates were made and the way in which they were presented are here described to illustrate the importance of this factor in mining operations. The saving due to lower costs is not the only factor that should be considered. The greater profit per ton is of much importance but of equal importance are the greater profit per ton that will be made on a greater number of tons per year, and the fact that the total profit will be received in a shorter; period. This last makes a great difference in the present value of a property, by shortening the period of discount on future profits. Another item of importance to those operating a number of mines is that the tonnage needed to supply the market can be obtained most profitably by operating the smallest number of mines that will supply the amount required when each is worked to maximum capacity. In the Lake Superior iron district there are many grades of ore, and the requirements for each are known. If the demand for a certain grade can be supplied from mines now operating, the development and mining of a new orebody of the same grade must result in lower rates of production and lower profits to all mines producing this grade. If a company is mining the same grade of ore from three mines when it can supply its needs by operating only two, by operating only two it can obtain the greatest profit. Royalty rates, lease terms, and other considerations modify this general statement, but if all three properties

Jan 5, 1922

Homestake's Bulldog Mountain Operation near Creede, Colorado, in the San Juan Mountains at an elevation of nearly 2,750 m (9,000 ft), is subjected to short summers and long cold winters. Creede’s history dates back to 1889 when silver ore was discovered; and by 1892 production of over a million dollars per month was being shipped from mines located along the Amethyst Fault. The Bulldog Mountain Fault remained relatively untouched by the early prospectors. The United States Geological Survey recognized the potential of this fault in 1960, which led to the staking of many claims over the structure. Homestake leased properties in 1963 and in mid- 1964 a tunnel was started at the 2,956 m (9,700 ft) level with encouraging mineralization being encountered. In 1968 a decision was reached to build a flotation mill of 318 mtpd (350 stpd) capacity. The erection of the mill was completed in early 1969, six years after the first exploration was begun. Since initial start-up, extensive drifting has been done on several separate levels. Two underground hoist installations serve the various levels and many thousand feet of vertical mining operations. Due to the unconsolidated nature of the vein, a new unique underhand cut-and- fill mining method was developed. This procedure is the reverse of the normal cut-and-fill and proceeds from the top down under cemented sand fill, which, while expensive, has greatly reduced s toping hazards. Prior to 1977, a considerable quantity of silver was lost in the slime fraction of the ores processed because of oxidation and other inherent characteristics of individual minerals. Due to Homestakefs favorable experience in treating the slime fraction of the Lead, South Dakota gold ores, experiments with leach methods to recover silver from the slimes by Carbon -In -Pulp offered' the potential for additional silver recovery. Work was begun on the Carbon-In-Pulp plant in April 1976 and completed in December of that year at a cost slightly exceeding $2 million. The C. I. P. plant was designed for 136 mtpd (150 stpd) of current plant slimes plus 227 mtpd (250 stpd) of slimes dredged from the old tailings during the summer season. The sand fraction of the flotation

Jan 1, 1981

By Wallace Ralston

DuRing the year of 1937, the East Texas district produced 211,194,467 hbl. of oil and marketed more than 22,329 million cu. ft. of gas; 3377 oil and gas wells were completed. During this same period 106 exploratory wells were drilled, discovering three new oil fields and one gas-distillate field. Fields East Texas Field.—The East Texas field again led the district as to production and number of wells completed. During the year, 2420 oil wells were completed, making a total of 24,382 producing wells, which produced 171,336,854 bbl. of oil, for a total of 1,156,352,834 bbl. since the beginning. During the year the average bottom-hole pressure dropped 49 lb., making the average bottom-hole pressure 1119 lb. Approximately 3500 wells are making salt water, 20 per cent of them making over 80 per cent of the water. During the month of December, the daily average production of salt water was 119,000 barrels. Talco Field, Titus and Franklin Counties.—The Talco field produced 9,780,948 bbl. of oil during the year, from 637 wells. During the year 472 wells were completed. All of the wells are pumping and 241 are making salt water. This field has followed a normal development and did not exceed the estimated number of acres reported last year. Rodessa Field, Cuss and Marion Counties.—The Rodessa field was extended about 13 miles southwest into Marion County, which added approximately 4000 acres to the field. During the year 260 wells were completed, making a total of 416 producing wells, which produced 12,646,-970 bbl. of oil. The author was unable to obtain figures for the amount of gas produced. The field has two gasoline plants, which had a daily average of 16,558,000 cu. ft. of gas during December, averaging 0.83 gal. per M cu. ft. As of Jan. 1, 31 wells were making salt water. The bottom-hole pressure varies greatly, depending upon the pay from which the well is producing. The average bottom-hole pressure from the Young

Jan 1, 1938

By Arthur F. Wendt

Within the last few years the production of iron, and of the metals generally, by a given furnace-plant, has been largely increased, in many instances trebled. Iron-furnaces exceeding one hundred tons' capacity per diem are now the rule in new constructions. Copper and lead-furnaces smelting from 60 to 100 tons of ore per day are common. With this greatly augmented product, the life of furnace-linings has been diminished, and recourse has been had to various cooling devices for prolonging the life of such liuings. The object of this paper is to call the attention of the profession to an arrangement recently patented by the writer. The common course of projecting water against the exterior of the brickwork of a furnace has been in a large measure abandoned by our most progressive managers. All have recognized the danger of this proceeding, especially when applied to the crucible of a furnace below the line of the tuyeres. Cast-iron water-jackets, with wroughtiron pipes for circulating the cooling-water, have replaced the cruder methods. In iron-smelting the use of such jackets has been confined to the crucible and the space around the tuyeres; and it has been the custom to support the jackets on the brickwork of the furnace. But the erosion of the brickwork below tuyere-jackets allows them to sag, and often displaces the alignment of the tuyeres and leads to other annoyances. The principle of construction adopted by the writer to remedy this and other evils, is to use a thin fire-brick lining (not over nine inches) from the tuyeres up to the bosh, to back this lining with wrought-iron or steel water-jackets, hung from the mantel-ring, and thus to carry the whole weight of the furnace and its filling upon the supporting pillars. The crucible proper is lined with three or four thicknesses of fire-brick on the sides, and not less than forty-eight inches in the bottom. It is supported on independent pillars, and is practically an independent structure. It could even be placed on wheels and made removable, were there any adequate advantage to be gained by such an arrangement.

Jan 1, 1885

By R. Maddin, W. R. Hibbard

A series of X ray experiments conducted by G. I. Taylor' in 1927 and later substantiated in 1939 by J. A. Collins2 both on axially strained aluminum single crystals, revealed evidence that during single slip crystallite rotation occurs in such a manner that " all parts of the material rotated about the transverse direction in the plane of slip."l The actual method of preparing the specimens for X ray examination is not discussed in detail by Taylor except to say that "this specimen was cut parallel to the plane of slip, as calculated from measurements of marks in the surface of the specimen. It was ground and etched till the effect of the new cuts had disappeared. This was verified by applying the same treatment to an un-distorted specimen. The X ray reflectionsl in this case were perfect ones."' Collins, on the other hand, cut his crystals in a mechanical shaper. These surfaces were polished on No. 1, No. 1/0, No. 2/0 and No. 3/0 papers and on a broadcloth lap using No. 600 alundum as a polishing medium. "Finally, the surface was deeply etched in Tucker's reagent. An unde-formed crystal was prepared in the manner described and X rayed to determine whether or not the machining and polishing operations had produced any strain or distortion in the crystal. The Laue spots all seem to be sharp, free from tails and streaks indicating no detectable strains had been introduced in the crystals." Taylor's X ray technique involved the use of "homogeneous X rays from an iron anti-cathode"; whereas Collins used Ka radiation of copper at 31kv and 20 milliamperes. Glancing angle X ray photograms were taken (1) with the axis of rotation of the spectrometer table in the plane of slip and at right angles to the slip direction, and (2) with the axis of the spectrometer table lying along the slip direction. However, eight minute exposures were used in each case and the angle setting of the spectrometer table was increased by one degree for each exposure. With the discovery of the action of three slip systems3 in the plastic deformation of single crystalline alpha brass where, formerly, only one had

Jan 1, 1950

By V. R. Garfias, C. O. Isakson

The production of petroleum in Mexico during 1930 was approximately 39,600,000 bbl., or 5,188,000 bbl. less than in 1929. The decline which has continued for the last eight years, will place Mexico in fifth or sixth rank as an oil-producing country. The production of the northern and southern fields near Tampico declined over 5,250,000 bbl., while that of the fields in the Isthmus of Tehuantepec moderately increased. The wildcat operations which have been conducted for some years near the international border along a 290-mile belt, extending roughly 170 miles northwest and 120 miles southeast from Laredo, Texas, have so far met with little encouragement, although the oil possibilities of the region warrant the belief that commercially productive fields will be discovered eventually. An interesting development during the year was the starting of construction of the oil pipe line from Palma Sola in the South Fields near sea level—over Sierra Madre at 8660 ft.—to Atzcapotzalco, a suburb of Mexico City at an elevation of 7350 ft. This line, about 146 miles long, has a diameter of 10 in. and an estimated daily capacity of 10,000 bbl., and with its terminal refinery at Mexico City will form a transporting and refining unit which should materially affect the distribution and marketing of refined products in the Republic. Development During the past year 148 wells were drilled, as compared with 214 in 1929 and 371 in 1928, the percentage of producers being 49 as against 47 in 1929. With the exception of one well in San Isidro, at the extreme southern end of the Golden Lane, the Jardln Paso Real area was the only sector of the old fields where new development could be considered as successful, all other producers brought in during the year being drilled in nearly exhausted pools to be operated as ('strippers." Northern Fields A total of 71 wells were drilled in the northern fields, of which 22 were producers; one well in Ebano was estimated at 5000 bbl. per day, while the general average of all producers was less than 300 bbl. Results

Jan 1, 1931

By Northcutt Ely

A year ago the petroleum code was in effect, and Congress had before it bills with powerful backing designed to extend and put on a permanent basis the Federal authority impliedly recognized in the petroleum code. Those men in the industry who were convinced of the unconstitutionality of Federal regulation, who believed in conservation, and who were seeking accomplishment of a conservation compact among the oil-producing states, were at that time encountering difficulties in bringing about such an agreement. Since then there has been a shift in the center of gravity. Today, by virtue of the Supreme Court's Schechter case decision, the petroleum code is not in existence, the industry is not operating under an oil administrator, and the Federal-control bills are not on Congress' calendar. In view of what the Supreme Court has said in the Schechter case and the Hoosac Mills case about the local character of mining and manufacturing, the problem today is not whether the Federal Government or the State Governments ought to regulate oil production, but how effective we can make the devices that are available to us under the constitution for the conservation of the nation's oil resources. The interstate oil conservation compact ratified during the past year by Texas, Oklahoma, Kansas, New Mexico, Colorado and Illinois, approved by Congress, but not yet in effect in California, is the mechanism now at work. Interstate Oil Conservation Compact What is this interstate compact? The basic theory is simple and logical. It has four elements to it. The first point is that in order to effect the maximum recovery of our oil arid gas reserves it is necessary for some governmental authority to regulate the way in which those resources are taken out of the ground, so that the reservoir energy is efficiently used, and used equitably by the various owners of the pool. Second, that the state, as distinguished from the national government, possesses the police power necessary to protect the public interest and to protect the correlative rights of the common owners of the oil pool. Third, that the state governments ought to cooperate with each other through an interstate advisory commission so that orderly production in one state is

Jan 1, 1936

By A. S. Richardson

THE rating of a mine ventilation fan, or the characteristic curves illustrating the duty it may be expected to perform under various mine conditions are, in general, determined by the fan manufacturers. The information is of importance to the operator, or engineer, of a mine in many ways. For instance, when an increased flow of air is desired and the fan speed is to be increased, it becomes necessary to know what increase in volume may be expected and what the power requirements will be. In other cases, it may be decided to make changes in the mine to reduce the resistance to the flow of air, or to make changes in the general system of ventilation. Under any changed mine conditions there will be a difference in the duty performed by the fan. When mechanical ventilation is adopted, the factors governing the selection of equipment for the new system include not only the requirements of existing conditions, but also those that may be expected with the development of the property. Efficiency of service is required over a variable range of operating conditions. Characteristic curves, giving the duty performed by their fans under variable resistance conditions, are published by most fan manufacturers. General statements as to the effect of variation in speed of the centrifugal-type fan, under fixed mine conditions, appear in textbooks and trade catalogs. However, to the author both sources of information appear to be unreliable, at least under certain circumstances. The catalog of a leading fan manufacturer says: 1. The volume of air delivered by a fan varies directly as the speed. 2. The pressure, or water gage, produced by a fan varies as the square of the fan speed. 3. The horsepower of a fan varies as the cube of the fan speed. While these statements are accurate when the fan is operating under conditions similar to those that exist when a blower is used to force air through a pipe, they are not correct under mine conditions that are by no means unusual. Such conditions may be found in deep mines operated through shafts, in which a wide range of temperatures may be

Jan 8, 1925

Discussion of the paper of DOUGLAS BUNTING, presented at the New York meeting, February, 1915, and printed in Bulletin No. 97, January, 1915, pp. 1 to 21. ARTHUR HOVEY STORRS, Scranton, Pa.-I know something about accidents Nos. 4 and 8. At the Fuller mine there was no disturbance of the surface in connection with either of those accidents, there was no surface settling, nor signs of sand in the mine, and seemingly the water all came from a subterranean basin or water-bearing stratum overlying the Six Foot vein. A similar thing was shown, in an accident not referred to in Mr. Bunting's table, at the Avondale, where we had an inflow of water, as high as 12,000 gal. a minute, for a considerable period. Regarding the second accident (No. 8) at the Fuller mine: after the first inflow of water (No. 4 of the table), the mining was abandoned in the Six Foot vein. A long slope was. driven in an underlying seam, and when this had reached a point about 2,000 ft. southeast of the place where the first inflow of water occurred, and where the bore holes show there was apparently sufficient rock covering for the Six Foot vein, a rock plane was driven up to the upper vein (Six Foot) and one afternoon this exposed the coal. During the following night the inflow of the water occurred. There were absolutely no workings at this point so that no disturbance of the overlying rocks could have occurred. The result of the inflow of water was to fill up the entire lower-vein workings in about two or three clays and caused the abandonment of the mine. After several years, considerable time and money were spent in an effort to hoist the water from the shaft and mine workings, with varying, but in the main rather indifferent, success until, clue to the breaking of one hoisting rope, the engineer pulled the other hoisting tank up through the tower and down on to the engine, making a complete wreck of the whole plant. It was then decided to allow the mine to soak and it is still doing so, other portions of the property being mined from adjoining collieries.

Jan 5, 1915