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By Charles R. Keyes

During the past decade the genesis of the lead- and zincdeposits of the Mississippi valley has received special attention from many distinguished observers. But their united egorts, instead of settling all disputed questions, have, in many respects, involl-ed the general problem in greater uncertainty than would be thought possible under the circumstances. In place of the harmony of opinion that might be expected, there is unexpected disagreement, largely due to the fact that, instead of giving attention to a possible multiplicity of ore-producing conditions among the different deposits, the attempt has been made to bring all deposits under a single genetic head. To a new observer of the lead- and zinc-deposits of the Mississippi valley, it appears at the outset that all the deposits cannot possibly have had the same genesis. In fact, different modes of origin have been often asserted for the ore-bodies, but the difficulty has been that each writer has referred them either all to one category or all to another, and no intermediate ground has been considered possible. Such a position now appears to be clearly untenable. The opinion that, in the deposits of the region under consideration, the ore-materials represent original depositions, made at the time the rocks themselves were formed, is no longer held by any authority, and therefore need not be considered here. Of late years, a number of writers have attempted to account for the presence of the lead- and zinc-ores on the hypothesis that the metallic materials arose in heated solutions from the

Jan 1, 1902

By J. A. Ede

THE object of the writer is to call attention to a rather unique aggregation of economic products distributed over a line of succeeding formations about 3 mi. long, to be seen within a few miles of La Salle, Ill. Fig. 1 is an ideal section of the stratification exposed and exploited along a distance of 3 1/5 mi. in a southwesterly direction from the quarry of the Utica Hydraulic Cement Co. located near the historic site of Kaskaskia village to the Oglesby, shaft at Oglesby. No attempt has been made to cover the whole field, special mention only being made (with the exception of two places) of the operations found along the course or parallel to the direction assumed in the ideal section. I have used Fig. 2, after J. H. Bent and De Witt Kelly, to locate the relation of the La Salle anticline to the coal mines of this district and to show the operation of No. 1 and 3 mines of the Illinois Zinc Co.

Jan 9, 1919

By J. J. Becker

BEAN1 has discussed the magnetic behavior of mixtures of small ferromagnetic particles on the order of 20 to l000A in diam. As he points out, there are three size categories with characteristic properties: 1) Particles large enough to contain many ferromagnetic domains magnetize initially by the motion of domain walls. The initial susceptibility of such particles, if domain-wall motion is assumed to be perfectly easy, depends only on their shape. It is equal to the reciprocal of the demagnetizing factor (and is thus 3/4 tt for a sphere) and is independent of temperature. 2) Smaller particles find it energetically undesirable to contain domain boundaries. They are always spontaneously saturated, and reverse their magnetization only by rotation of their entire magnetic moment. As assemblage of such particles has a remanence which is a large fraction of the saturation of the assemblage; its coercive force is on the order of 2K/1,, where K indicates magnetic aniso-tropy from any source, and I, is the saturation magnetization of the substance of which the particles are made. 3) Particles which are still smaller continue to be single-domain, but the direction of their magnetization fluctuates thermally, as first pointed out by Neel.' They have no remanence and no coercive force and possess the temperature-dependent magnetization curve of a paramagnetic substance with a very large moment. Bean calls this superpara-magnetism. All of these kinds of behavior are observable in alloys consisting of a precipitate of ferromagnetic phase in a nonferromagnetic matrix. Fig. 1 shows a typical aging curve for the room temperature coercive force of a sample of 98 pct Cu-2 pct Co alloy

Jan 1, 1958

By Frank Wilder

THE most important process in a gypsum mill is calcining the crude mineral. There seems, however, to be little progress or change in calcining methods. This would not be surprising if the industry was not, in other ways, developing. The demand for gypsum in its various forms, however, is growing rapidly. The output has more than doubled in six years, while the value of gypsum products, through the introduction of higher priced specialties like wall board, has nearly trebled in the same period. In other industries, under somewhat similar conditions, calcining in rotating cylinders, either by direct or indirect heat, has replaced the method that still prevails in gypsum mills. Efforts were made to use rotary calciners in manufacturing plaster of Paris in the early days of the industry in America; 25 years ago rotary calciners were in use in Germany. At that time there was great diversity of opinion in regard to their merit. In 1923, the output of calcined gypsum in the United States was 3,101,378 tons. About nine-tenths of this material was calcined in kettles, the remainder in rotary calciners. The ratio was about the same 10 years ago. During these 10 years, rotary calcining made rela-tively no gains, and there were no important changes in the construction of kettles. In their manipulation, the only change of consequence was in connection with the length of time that the gypsum is left in the kettle. For wall-plaster purposes, all producers who had not previously done so changed from second-settled to first-settled calcined gypsum, thereby reducing production costs and improving the plasticity and sand-carrying capacity of their plaster. Nevertheless, in the few mills in which they were installed, rotary calciners continue to operate, with possibly one or two exceptions, and to be highly successful. In these 10 years, the Cummer type of rotary calciner has disappeared. All rotaries now used are of the cement-mill type with a diameter of 6 or 7 ft. and length of 80 to 120 feet.

Jan 2, 1925

By Roy A. Hardy

The Getchell mine is a comparatively recent discovery in the old Potosi mining district, Humboldt County, Nevada, a district organized in the seventies and eighties, in which some prospecting was done in several metamorphic zones along a monzonite-sedimentary contact. The district had no production in the early days and no further work was done until the same metamorphic zones were prospected for tungsten (scheelite) in 1917 and 1918, when a few small lots were shipped. It again lay dormant until 1934, when prospectors investigated a large siliceous escarpment at one end of the old district where outcroppings were a prominent feature of the topography. Undoubtedly, during the early prospecting of the district, the outcroppings had been investigated for mineral, probably by panning, with negligible results because the gold later found is invisible in the concentrate and is refractory. A fire assay revealed the presence of sufficient gold to warrant development work. The outcroppings were easily prospected by short tunnels having their portals in the siliceous material on the hanging-wall side, with a maximum distance to crosscut to the footwall of 135 ft., or a distance at right angle to dip of 60 to 90 ft. Development work, reaching a depth of over 600 ft. on the dip of the vein, was done by means of various crosscut tunnels, winzes and laterals. A churn-drill hole was also sunk, which intersected. the vein at a depth of 1100 ft. on the dip. Sufficient development work of this character was completed by 1937 to justify the erection of a reduction plant to roast the sulphide ore and cyanide the calcine, and to treat the oxidized ore by straight cyanidation, to make a doré bullion for shipment to the mint. The erection of the plant was started that year and finished early in 1938; with a combined capacity of about 800 tons per day. It has operated continuously since erection and recently was enlarged to handle 1000 tons per day. The vein dips with the slope of the mountain, and by stripping the hanging wall the ore may be mined by power shovel for several hundred feet below the outcrop. Thereafter underground methods will be necessary.

Jan 1, 1941

By John B. Mertie

MONAZITE formerly was described as moribund, but, in the light of recent developments, it is no longer so. It is the common source of the rare earths and thorium, both of which are becoming progressively important in industrial and other applications. Moreover, by the action of foreign governments, the sources on which the United States has depended for its supply are now either restricted or cut off entirely. Monazite has thus become a scarce mineral and processors in this country are endeavoring to acquire it from all available sources. RARE EARTHS AND THORIUM The rare earths proper, as defined by spectroscopists, are the oxides of cerium, praseodymium, neodymium, prometheum, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutecium, with atomic numbers ranging respectively from 58 to 71. Chemists include with the rare earths scandium, yttrium, and lanthanum, with atomic numbers respectively of 21, 39, and 57. Thorium, with an atomic number of 90, is analogous to lanthanum, in that it precedes a second group of elements, whose oxides constitute the "rare earths of higher order." These are protactinium, uranium, neptunium, plutonium, americium and curium, with atomic numbers ranging respectively from 91 to 96. The last four mentioned are artificially prepared elements that so far have not been detected in nature. The rare earths with odd atomic numbers, except europium and lutecium, have no natural isotopes; and the two exceptions have only two isotopic forms. Those with even atomic numbers have from 4 to 7 natural isotopes. Samarium148 is radioactive, disintegrating over a half- life of 1.4 X 10 11 years with the emission of alpha rays. Lutecium176 is weakly radioactive, disintegrating over a half-life of 2.4 X 1010 years, with the emission of beta and gamma rays. At least 64 radioactive isotopes of the rare earths proper have been artificially prepared. Thorium is a strongly radioactive element, with a half-life of 1.39 x 1O10 years, which disintegrates through a series of 14 isotopes of 10 elements. The two longest lived and most important of these are

Jan 1, 1949

By Roy A. Hardy

The Getchell mine is a comparatively recent discovery in the old Potosi mining district, Humboldt County, Nevada, a district organized in the seventies and eighties, in which some prospecting was done in several metamorphic zones along a monzonite-sedimentary contact. The district had no production in the early days and no further work was done until the same metamorphic zones were prospected for tungsten (scheelite) in 1917 and 1918, when a few small lots were shipped. It again lay dormant until 1934, when prospectors investigated a large siliceous escarpment at one end of the old district where outcroppings were a prominent feature of the topography. Undoubtedly, during the early prospecting of the district, the outcroppings had been investigated for mineral, probably by panning, with negligible results because the gold later found is invisible in the concentrate and is refractory. A fire assay revealed the presence of sufficient gold to warrant development work. The outcroppings were easily prospected by short tunnels having their portals in the siliceous material on the hanging-wall side, with a maximum distance to crosscut to the footwall of 135 ft., or a distance at right angle to dip of 60 to 90 ft. Development work, reaching a depth of over 600 ft. on the dip of the vein, was done by means of various crosscut tunnels, winzes and laterals. A churn-drill hole was also sunk, which intersected. the vein at a depth of 1100 ft. on the dip. Sufficient development work of this character was completed by 1937 to justify the erection of a reduction plant to roast the sulphide ore and cyanide the calcine, and to treat the oxidized ore by straight cyanidation, to make a doré bullion for shipment to the mint. The erection of the plant was started that year and finished early in 1938; with a combined capacity of about 800 tons per day. It has operated continuously since erection and recently was enlarged to handle 1000 tons per day. The vein dips with the slope of the mountain, and by stripping the hanging wall the ore may be mined by power shovel for several hundred feet below the outcrop. Thereafter underground methods will be necessary.

Jan 1, 1941

By B. Haimson, C. Fairhurst

One of the main functions of rock mechanics research has been to find ways of determining in-situ stresses. Many methods have been suggested, the most significant ones calling for measurements inside bore- holes. These methods usually employ some instrumentation for the purpose of measuring hole deformation. Several years ago, a new method was suggested by Scheidegger,l based on previous work by Hubbert and Willis.2 It was the method of "hydraulic fracturing," which had been introduced by the oil industry in 1948 for the purpose of oil-well production stimulation. Basically, hydraulic fracturing consists of sealing off a section of a borehole, pumping in a fluid, and pressurizing it until fracture occurs. If pumping is continued vigorously, the fracture is opened up and extended. In an oil field, such an artificial fracture increases the overall permeability of the formation and usually enhances production. During the entire operation, the variation of pressure with time is ordinarily recorded. Hubbert,2 Scheidegger,1 Kehle,3 and others have shown that the recorded pressures can be theoretically related to the magnitudes of the principal in-situ stresses; the orientation of the fracture can often be used to determine the direction of the principal stresses. The advantage of hydraulic fracturing over the present in-situ stress determination methods is simplicity: no sophisticated instrumentation is required inside the borehole; hence, the stresses can be measured at any depth. Moreover, if the formation is impermeable to the fracturing fluid, no elastic constants of the rock are required in calculating the stresses, a

Jan 1, 1970

Discussion of the paper of HOWLAND BANCROFT, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1767 to 1769. THEODORE SIMONS, Butte, Mont. (communication to the Secretary*). -While preparing maps and models for use in mining litigations the writer was frequently confronted with the problem referred to in Mr. Bancroft's paper. His chart gives the apparent angle of dip with which a vein should be plotted on a vertical section not at right angles to the strike of the vein. For a quick determination of this apparent angle the writer has used an exceedingly simple graphical method, which he believes may prove helpful to engineers engaged in practical work. It is submitted, not as a criticism of Mr. Bancroft's paper, but as a means of solving the same problem when no chart is available and when calculations would consume too much time. The writer's method requires merely a few lines marked off on a piece of tracing cloth, as shown in Fig. 1: Draw line be on any convenient scale. At b erect a perpendicular, ba. By means of a protractor cut off on ba a number of angles within the probable range of variation of dip, so that a line connecting a and c, for instance, forms an angle of 60° with be, etc. With b as a center and be as a radius, draw a circle through c. This completes the tool for solving the problem. Fig. 2 represents the line of strike of the vein and db the trace of the vertical plane on which the vein is to be plotted with the apparent angle of dip. A° is the angle which this plane makes with the strike. Fig. 3 shows the application of the method: Place line cb of tracing over line db of Fig. 2 and move fore and back until line of strike becomes tangent to the circle. Connect d with the point (a) that marks the true angle of dip as found by measurement in the mine (60° in the case illustrated). The angle adb is the apparent angle of dip (C°) to be used in the vertical section. Proof.-As stated in Mr. Bancroft's paper, the apparent angle of dip is: tan C° = sin A° tan B° (1)

Jan 12, 1914

By J. A. Jr. Church

I. EARLY FURNACES. COPPER blast-furnace construction in America has long recognized a general standard in the rectangular mater jacketed shaft with separate forehearth. The details, however, and especially those relating to shaft dimensions, have had to meet a great variety of conditions, and show no uniformity whatever. Selecting a few of the present day Western plants, we find furnace lengths varying from 12.5 to 87 ft., widths at tuyere level from 42 to 84 in., and heights above tuyeres from 5 ft. 4 in. to 22 ft. 4 in. ; and comparing present designs with those of the past, we meet contrasts no less striking. Unlike its transverse section, the length of a furnace has come to depend rather on the size of unit desired than on the requirements of smelting ; and if the question of length be ignored, several of the various existing designs can be grouped together on the basis of a common transverse section. This section, having a width at tuyere level of 56 in. and a height above tuyeres of 18 ft., was developed at Great Falls, and the story of its development contains some interesting features. Ground was broken for the Great Falls works in the spring of 1891. About a year later, the concentrator was able to begin operation, followed within the next few mouths by the Brueckner, reverberatory, and converter departments, and in April, 1893, by the first blast fur-

Jan 7, 1913

By T. R. Armstrong

During the year 1939, Mexican production totaled 42,479,000 bbl.; a daily average of 116,381 bbl. or a little over 2 per cent of the estimated world production. The Mexican Government operates 100 per cent of the refining branch of the industry, 100 per cent of the domestic distribution, 96 per cent of the crude production and 92 per cent of the total exports. No discussion of the Mexican petroleum industry in 1939 is adequate without reference to the "expropriation" of the foreign-owned oil properties in Mexico by executive fiat on March 18, 1938. The forcible seizing of the properties culminated a long series of efforts on the part of the Mexican Government to obtain control of the oil properties developed through foreign initiative and with foreign capital in Mexico. The heart of the issue is whether the Mexican nation or any nation may with impunity confiscate the legally acquired properties of American citizens. The Department of State of our Government has in its communications to Mexico emphasized the fact that its "expropriation" of American properties was confiscatory because Mexico had failed to make "adequate, effective and prompt compensation"; that the taking was no less confiscatory "because there may be an expressed intent to pay at some time in the future," and that, consequently, "Mexico has assumed and continues to assume to exercise a right without compliance with the condition necessary to give such exercise a recognizable status of legality." Mexico has professed its willingness to pay for the oil properties but at the same time through its Supreme Court it has declared that the owners or lessees do not have the exclusive right to extract and dispose of the oil in the subsoil. This is a reversal of the Mexican position with respect to oil as set forth in the Mexican mining laws, affirmed by Mexican Supreme Court decisions, and as clarified in the Warren-Paync and the Morrow-Calles agreements, as well as in diplomatic correspondence. Efforts to Settle the Controversy Responding to suggestions from the State Department, representatives of the principal oil companies undertook in 1939 to effect a direct

Jan 1, 1940

By N. A. Elmslie

This subject covers much ground, therefore it must be treated in a general way rather than in detail in this paper. Personnel To approach the measure of a mine, it is, of course, essential that the personnel be measured, and this measuring must be done in a circumspect manner and conclusions must be reached slowly. There may be one unit in the personnel of an organization that may be out of step with the remainder of the organization, not always because of lack of ability, but because of misplacement or lack of proper measurement of his capabilities. Too much time can scarcely be spent in the study or measure of the personnel ; in fact, a manager or a superintendent of a mine never completes his work along this line. Mine or Plant Just as no two men are alike, so no two mines or plants are alike; and yet there are many similarities. Find out what the similarities are, and this will help to make clear the dissimilarities. Try to visualize details of the difficulties, not because you will have to deal with them yourself, but to consider them in later studies of general problems. To outline all the steps to be taken in familiarizing oneself with a plant or operation would be impossible, but the following points may be of interest in any investigation. The study of a mine is generally made backwards-—that is to say, one sees the finished product first-—-but this is immaterial, because each step must be considered separately in any event. As a rule, there are certain heads under which the different features of mining can be placed, as follows: Ventilation.—Ventilation is usually the most important item in power cost and safety, especially in gassy mines. Quantity of air, water gage and power consumption, and finally analysis of the return air in full return and separate splits should be considered. Type of fan and type of power unit should enter into this study because it is important to view expenditures which are going on 24 hr. a day and 36.5 days in the

Jan 1, 1931

By B. B. Cox

Iraq, formerly called Mesopotamia in Asiatic Turkey, became a kingdom under British Mandate after the world war and is expected to gain its independence in 1932 when it enters the League of Nations. The kingdom is shown on Fig. 1 in its relations to neighboring countries, to the Mediterranean Sea and to the Persian Gulf. It is slightly smaller than the State of Texas with its capitol, Baghdad, inland about as far from the Persian Gulf as Breckinridge, Tex., is from the Houston Shipping Channel. The oil fields lie 180 to 225 miles north of Baghdad, or about as far as from Breckinridge to Oklahoma City, and about as far from the Mediterranean as Fort Worth is from Hobbs, N. M. A narrow-gage railway runs from Basra, the Persian Gulf port, to Baghdad. From there another narrow-gage runs into the Kurdish hills east of the Tigris to Kirkuk. A standard-gage, part of the old Berlin-Baghdad system, follows the west bank of the Tigris northward from Baghdad to Baiji, a village about 100 miles south of Mosul. No railway exists between Iraq and the Mediterranean, though the Anatolian Railways in southern Turkey come to within 50 miles of the Iraq frontier and 120 miles of Mosul. Surveys have been completed for a railway through British Mandates from Haifa to Baghdad as well as for a railway through French Mandated Syria from Tripoli to Abu Kemal near the Iraq border. Wagon roads, excepting those constructed by the oil companies, are few and indifferent in Iraq and no road exists across the desert to the Mediterranean, but contrary to prevalent beliefs the surface is firm and free from sand dunes so that motor cars can go almost anywhere in dry weather, with ease. Frequent motor car and airplane service exists between Baghdad and the Mediterranean ports and motor car service may be had between Kirkuk and Nisibin, Turkey, where on two days each week through Wagons Lits service is available to Paris. Baghdad is about 21 days distant from New York City with present transport facilities. The climate is semiarid, similar to Imperial Valley, California, the average rainfall outside the mountainous parts amounting generally to

Jan 1, 1932

By T. R. Armstrong

During the year 1939, Mexican production totaled 42,479,000 bbl.; a daily average of 116,381 bbl. or a little over 2 per cent of the estimated world production. The Mexican Government operates 100 per cent of the refining branch of the industry, 100 per cent of the domestic distribution, 96 per cent of the crude production and 92 per cent of the total exports. No discussion of the Mexican petroleum industry in 1939 is adequate without reference to the "expropriation" of the foreign-owned oil properties in Mexico by executive fiat on March 18, 1938. The forcible seizing of the properties culminated a long series of efforts on the part of the Mexican Government to obtain control of the oil properties developed through foreign initiative and with foreign capital in Mexico. The heart of the issue is whether the Mexican nation or any nation may with impunity confiscate the legally acquired properties of American citizens. The Department of State of our Government has in its communications to Mexico emphasized the fact that its "expropriation" of American properties was confiscatory because Mexico had failed to make "adequate, effective and prompt compensation"; that the taking was no less confiscatory "because there may be an expressed intent to pay at some time in the future," and that, consequently, "Mexico has assumed and continues to assume to exercise a right without compliance with the condition necessary to give such exercise a recognizable status of legality." Mexico has professed its willingness to pay for the oil properties but at the same time through its Supreme Court it has declared that the owners or lessees do not have the exclusive right to extract and dispose of the oil in the subsoil. This is a reversal of the Mexican position with respect to oil as set forth in the Mexican mining laws, affirmed by Mexican Supreme Court decisions, and as clarified in the Warren-Paync and the Morrow-Calles agreements, as well as in diplomatic correspondence. Efforts to Settle the Controversy Responding to suggestions from the State Department, representatives of the principal oil companies undertook in 1939 to effect a direct

Jan 1, 1940

By Wilbur A. Nelson

In 1839, Gerard Troost,1 the first State Geologist of Tennessee, reported the occurrence of zinc ores in east Tennessee, in connection with the iron ores at Embreeville; in 1844,2 he refers to the zinc deposits of east Tennessee, especially the apparently rich deposits occurring in Jefferson and Claiborne Counties, while his ninth annual report 3 s a description of the zinc deposits of Jefferson County and a description of the most improved processes by which zinc is extracted from its ores. Yet, only during the last few years have these ores been successfully worked. As far as can be learned, prior to the systematic development of the Mascot district in 1911, no large-scale or successful operation of any of the zinc deposits was carried on. But in that year, after several companies had made considerable progress in developing the Mascot area and had proved a relatively extensive body of low-grade sulfide ore, the American Zinc Co. entered the field. It introduced modern methods of prospecting and mining and from the first was successful. Too great credit cannot be given this company for its pioneer work in a previously unimportant field. Throughout the history of its operations, the American Zinc Co. has confined its efforts to underground mining of the sulfide ore, sphalerite. This company has found that successful results in zinc mining in east Tennessee can be achieved only by expending large sums in prospecting and blocking out bodies of pay ore in sufficient magnitude for large-scale operations. At Mascot are located the mines of the American Zinc Co. of Tennessee, the mines being situated along the Southern Railway in the Ilolston River Valley, Knox County, about 13 miles northeast of Knox-ville. At first only open pits, which were worked for oxidized ores, were operated and the production was small. In 1900, the Roseberry Zinc Co. was organized and sank to a depth of 187 ft. what is now known as No. 3 shaft of the American Zinc Co. The upper 30 ft. was in residual clay,

Jan 1, 1925

By H. Margolin, E. Ence

In order to understand the effect of zirconium on properties of Ti-Cu-A1 alloys, Ti-Zr alloys were examined for the presence of ordering or compounds at the following compositions in weight percent: 24.1 pct Zr (lZr:GTi), 32.2 pct Zr (lZr:4Ti), 38.8 pct Zr (lZr:3Ti), 49.0 pct Zr(1Zr:ZTi). Alloys were prepared as 15-g buttons by non- consumable arc melting under argon atmosphere from Bureau of Mines titanium (Bhn 63) and Reactor Grade zirconium (Bhn 150). Weight losses during melting did not exceed 1 pct of the initial button weight. Prior to heat treatment, buttons were hot-rolled at 600" to 700°C to rods of about 6 mm diam. Contamination after hot-rolling was found to extend to a depth of less than 0.5 mm. Specimens for heat treatment were wrapped in molybdenum sheet, annealed in argon-filled quartz capsules, and quenched by breaking the capsules under iced brine. Annealing times were as follows: 700°C — 7 days; 600°C— 14 days; 575°C-1 and 2 months; 525°C-2 months; 500°C-2 months. Prior to heat treatment, all Ti-Zr alloys were vacuum annealed at 900°C to remove hydrogen. The reanneal of 575°C specimens for an additional month produced no observable microstructure changes. The results obtained by microstructure and X-ray diffraction are shown in Fig. 1, together with data of Hayes et al.' No other phases than a or P were found. Small amounts of retained P were detected by X-ray in the 49 pct Zr alloy. The data of the present investigation suggests that ß and a transus boundaries are at considerably lower temperatures than those of Hayes et al. The work of Hayes et al. is based on sponge titanium and Bureau of Mines zirconium, both of which contained 0.15 pct 0. Since melting was performed in

Jan 1, 1962

By Frank W. Osterwald

Violent, spontaneous destruction of coal faces and ribs during, what are commonly called, bumps endangers and at times destroys life and property in mines of the Book Cliffs coalfield, Carbon County, Utah. Because these mines supply much of the coking coal for the West Coast steel industries, mining is necessary, although costs are high and operating conditions are very difficult at times. As operations continue, mining will go to greater depths, and the difficulties will increase. Whether or not mining can be continued successfully depends in part on whether or not incidence of bumps can be controlled successfully. For this reason, the U.S. Geological Survey, at the request of and in cooperation with the U.S. Bureau of Mines, undertook a study of the Sunnyside No. 1 mine to determine what geologic factors were related to the incidence of bumps. This report presents the preliminary results of that study and indicates that some observable geologic features in the mine may be related directly or indirectly to bumps, and that other features may be used to infer stress distribution around workings that will aid in design of roof support measures. Coal is mined in the Sunnyside No. 1 mine from depths as great as 2500 ft by room-and-pillar methods. The surface topography is rugged with many steep cliffs and deep canyons, hence the load on the coal varies greatly within short distances. Much of the Sunnyside coal is under high stress, and while being mined, it shatters continuously' and falls from the face. Continuous shattering (bumping) makes mining easy, but if the shattering is interrupted, greater stress is built up and violent bumps may result when the coal is mined.

Jan 4, 1962

By Eugene McAuliffe

IT is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the "do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co. has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as "extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. It is the writer's purpose to show in this paper that marked and even extraordinary betterment can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go.

Jan 1, 1938

By L. Douglass Anderson

For some years past the annual reviews of the metallurgy of lead have almost uniformly stated that there have been no great changes, such as there were being more particularly noticeable in the refinement of details. While this is quite true, nevertheless these changes in details are gradually bringing about a condition that, taken as a whole, constitutes a considerable advance in the art. Local circumstances have often compelled metallurgists to adopt certain peculiarities of practice which upon trial have been found advantageously applicable to more than the restricted district of origin. This paper will deal with some of the more novel features developed in recent years at the United States smelter, Midvale, Utah, particularly with reference to the influence of the bag house. The plant is equipped with six blast furnaces, 48 by 160 in., mechanically fed; four Wedge furnaces for roasting matte and sulphide ores; four Dwight-Lloyd sintering machines; 20 converter boxes for blast roasting; storage bins for ore, fuel, and fluxes; "oxide" and "sulphide" sampling mills; bag house taking all the gases of the plant; arsenic plant for treating the dust gathered there; laboratory, shops, etc. The most marked feature of the plant is its complete bag-house system. Of the many schemes thus far tried for preventing damage to surrounding agricultural interests the writer is aware of none as yet quite as efficient as the bag house. A common remark of visitors upon approaching the plant and viewing the clear stacks is that it appears to be shut down, whereas once inside all the evidences of industry are found. Bag-housing blast-furnace gases presents no peculiar difficulties. The gases from properly run furnaces are comparatively cool, contain scarcely a trace of acid and do not burn the filtering medium. All that is required is a proper mechanical design of the bag house and its accessories, the provision of ample filtering area, and of convenient means for handling and treating the product. While cotton or duck bags have been used, on the whole woolen bags woven of the raw wool appear to give sufficiently longer life to warrant their heavier expense. As for the filtering

Jan 1, 1915

By C. S. Corbett

There is much comment at present in the ranks of the oil industry regarding unit operation of oil fields and the benefit that would accrue if it could be extensively applied. It seems certain that, as an immediate corrective of the present situation, overproduction could be effectively curtailed with all the advantages of proper conservation of petroleum resources and with no important loss to anyone connected with the industry. Unit Operation in Certain Foreign Fields Many an oil operator in America would doubtless like to have exclusive control of one or more oil-bearing structures for development in accordance with the economic position of the industry and especially in accordance with the best production practice known. A few operators now have this privilege, particularly in certain foreign fields, and are following lines of procedure which show that they are aware of the great opportunity that is theirs. We find in an article by Professor Strigeoff,1 and in a paper read by Captain Comins2 before the American Petroleum Institute, the outlines of procedure adopted, respectively, by the Soviet Government for the nationalized Russian oil fields and by the Anglo-Persian Oil Co. for its fields in Persia. Comprehensive plans for the unit operation of other oil fields may have been described publicly but no such descriptions have come to the attention of the writer. New fields are coming more and more into the hands of single operators or of a few who control large activities and who appreciate fully the need for cooperative action and are willing to forego the lure of a large quick profit from high flush production in order to secure the advantage of better stabilization in the industry and a larger though more deferred profit by operating the field as a unit. Much can be done toward efficient development of an oil field controlled by a few operators who are willing to cooperate for that purpose, but the best result can be obtained only by pooling their interests in the field

Jan 1, 1930