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(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members) The following is a partial list of members and guests who called at Institute headquarters during the period June 10, 1917, to July 10, 1917. Guy N. Bjorge, Boston, Mass. H. H. Lauer, Allentown, Pa. A. H. Burroughs, Jr., Britannia Beach, E. C. Lee, Pittsburgh, Pa. B. C., Canada. Montrose L. Lee, Port-au-Prince, Hayti. Karl Eilers, New York, N. Y. Eugene McAuliffe, Paducah, Ky. H. S. Emlaw, Grand Haven, Mich. R. H..McMillen, Pittsburgh, Pa. W. R. Hamilton, San Francisco, Cal. L. D. Moore, Providence, R. I. Fred N. Hays, Sharon, Pa. Fred J. Pope, New Rochelle, N. Y. E. Hibbert, Nickelton, Ont., Canada. George S. Rice, Washington, D. C. Charles Janin, San Francisco, Cal. W. G. Swart, Duluth, Minn. Milton A. Allen has resigned his position with the Federal Lead Co. and accepted a position with the Arizona State Bureau of Mines, Tucson, Ariz. L. W. Bahney has resigned as Professor at Yale University and accepted a position as metallurgical engineer with the Scovill Manufacturing Co., Waterbury, Conn.

Jan 8, 1917

By Pol Duwez, Paul Pietrokowsky

Titanium and vanadium form a complete series of solid solutions at temperatures above 885°C. Below 885°C, vanadium is slightly soluble in a titanium (about 1.5 pct V at 650°C) and a two-phase a plus ß region extends to 18.5 pct V at 650°C. The alloys up to 15.0 pct V transform into a supersaturated a solid solution upon rapid cooling from the ß phase. Above 15 pct V the ß phase may be retained. The temperature at which the ß to a' martensite-type transformation takes place decreases steadily from 850°C for 0.5 pct V to 325°C for 12.7 pct V. IN the transition series of the periodic table, the six elements that have a body-centered cubic structure at all temperatures, namely chromium, vanadium, molybdenum, columbium, tungsten, and tantalum, fulfill the conditions required for the existence of complete series of solid solutions with the high temperature (ß) form of titanium. Up to the present time, complete solubility at temperatures above the a to ß transformation of titanium has been observed in the systems Ti-MO,1,2 Ti-Cb,2 Ti-W,³ and Ti-Ta.³ The two remaining elements, vanadium and chromium, have atomic diameters which are not as near that of titanium as the atomic diameters of the four other elements. Both are smaller than titanium and the difference, expressed in percentage of the titanium atomic diameter, is 12.3 pct for chromium and 8.2 pct for vanadium. On this basis, the least favorable conditions for solid-solution formation are therefore encountered in the Ti-Cr system. The early work on the Ti-Cr system4 revealed that up to about 1100°C the solubility of chromium in ß titanium is limited, and an intermetallic phase exists near the stoichiometric composition TiCr2. It was found later' that a continuous series of solid solutions extends across the diagram at higher temperatures, and TiCr2 forms by solid state reaction. It became apparent therefore that complete solubility would also be present in the Ti-V system. The present investigation confirms this possibility. The iodide-refined titanium used in this investigation was purchased from the New Jersey Zinc Co., New York. According to the manufacturer, a typical analysis of this product is 0.0065 pct Mn, 0.0022 pct Fe, 0.0015 pct Cu, and 0.0042 pct Pb. The Vickers hardness number (10 kg load) of the crystalline bar varies between 55 and 80. The vanadium metal was purchased from the Westinghouse Electric Corp., Lamp Div., Bloomfield, N. J. The purity of this metal is probably above 99 pct V. The oxygen content must have been quite low, since a bar about 1/4 in. square could be cold rolled into a ribbon 0.020 in. thick. To prepare the various alloys on the titanium-rich side of the diagram, the titanium rod was machined into cups 1 cm in diam and about 1.5 cm high. Pieces of vanadium, of the proper weight, were cut from the square bars and placed within the cups prior to melting. On the vanadium-rich end of the diagram, single pieces of the metals, in the proper weight pro-

Jan 1, 1953

By J. P. Martin, A. H. Geisler, J. H. Crede, E. Both

The investigation of a 50 pct Co alloy was undertaken to determine whether there was any direct correlation between the structure and properties of Co-Fe alloys which were given various magnetic heat treatments. The magnetic anisotropy and texture of the 0.002-in. cold-reduced 98 pct material tend to decrease and change in nature with increasing temperature of the recrystallization anneal. Annealing samples in a magnetic field had little effect on either the magnetic properties or texture. However, cooling them in a magnetic field greatly improved their magnetic properties. THE beneficial influence of a magnetic field applied during the heat treatment of certain soft magnetic materials has been known for a long time. Early work showed that the presence of a magnetic field of a few oersteds during the heat treatment of Fe-Ni alloys will cause a large increase in maximum permeability. A pronounced increase in the residual induction which is produced by the magnetic anneal causes the hysteresis loop to approach the shape of a rectangle. Such results are beneficial since the desired properties are high permeability, high induction at maximum permeability, high residual induction, and low coercive force. More recently Libsch and coworkers1 studied the effect of magnetic annealing on the hysteresis properties of a series of Co-Fe alloys prepared from powders. They observed good response for the 35 and 50 pct Co alloys but little response for the 42 pct Co alloy. They pointed out that this was somewhat surprising since the 42 pct alloy has a high linear magnetostriction and zero crystal anisotropy and similar conditions in Fe-Ni alloys give excellent response to magnetic annealing. They found optimum properties to be at the 50 pct composition with residual induction, Br = 19,000 gauss and coercive force, Hc = 0.68 oersteds after the magnetic anneal. Before the magnetic anneal these values were B, = 12,600 gauss and Hc = 1.15 oersteds. The optimum treatment consisted of cooling from above the y-a transformation temperature to 900°C in a field of 20 oersteds, holding 11/2 hr at 900°C, then cooling at a rate of 20° to 25°C per min in the field to below 230°C. Cooling rate mainly affected coercive force with the value decreasing from 1.09 to 0.88 oersteds as the rate was increased from 3° to 48°C per min. Cooling from 1020" to 900°C in a field followed by further cooling to 230°C without the field gave properties decidedly inferior to those for samples annealed with the field applied throughout the cooling. They concluded that to get the best properties the samples must be cooled in a field to a threshold temperature above which the alloy is plastic enough to be affected by magnetostriction. In this respect the holding temperature must be high enough so that the alloy exhibits good plasticity to permit the optimum orienting of magnetic domains by relaxation of magnetostriction. In contrast, the holding time was of less significance for there was little improvement when the time exceeded 1/2 hr. The improvement in properties effected by magnetic annealing has usually been attributed to the establishment of a domain texture caused by the "freezing in" of magnetic strains. On the other hand, Smoluchowski and Turner2,3 apparently found that a magnetic field applied during recrystallization could alter the crystal texture. If this effect is real, improved properties would also be expected when

Jan 1, 1954

THE great development of the mines and metallurgical works of this country during the last few years, accompanied as it has been by the investment of enormous sums of money in purchasing lands, and in the erection of improvements, requires that advantage should be taken of the accumulated knowledge of engineers, superintendents, and' others, in mastering &he problems which are constantly presenting themselves for our action. Among those may be mentioned the consideration of more economical systems of mining in our coal and metal-liferous mines, improved methods of transportation above and below ground, unwatering and ventilating mines, the mechanical preparation of coal and other minerals, the various metallurgical processes, and, in fact, every question tending to the attainment of two great objects : 1st. The more economical production of the useful minerals and metals. 2d. The greater safety and welfare of those employed in these industries. In European countries, where the arts of mining and metallurgy have long been the subject of the most careful study, no means have been found so effectual in attaining the end above proposed as the free interchange of experience among those actually engaged in these industries, and this object has been accomplished, mainly, through the medium of institutes, associations or societies, composed of those engaged in these occupations, and by the periodical publication of essays or papers, communicated to such societies by their members. I t must be evident to all practical men that the interchange of the varied experience of those engaged in such occupation in this country could not fail to advance very materially the desired objects; it is, therefore, proposed to establish an American Institute of Mining Engineers, which will hold its meetings periodically in the great mining and metallurgical centers, where works of interest, such as mines, machine shops, furnaces, and other metallurgical works, can be inspected, and the members exchange their views, and consult for mutual advantage upon the difficulties encountered by each; these transactions or proceedings, when published, would form a most valuable and greatly-needed addition to our professional literature. I t is proposed that a meeting of those sympathizing with the object above mentioned shall be called for the purpose of organizing such an association, the place and time of meeting being Wilkes-Barre, Pa., and the month of April or May. Communications indicating the opinion and wishes of all, both as to these points, and also as to the organization and objects of the Institute, will be gladly received by any of the undersigned, and a notice of the date of meeting, which will be arranged to suit the greater number, will be duly communicated. Any

By AUGUSTUS J. MONKS, Norman L. Weiss

THE Santa Barbara Unit of the Compania Minera Asarco, of which the San Diego mill is a part, is in the Parral District of southern Chihuahua. Although the concentration of sulfide ores has been practised in Santa Barbara since 1900, the San Diego mill, completed in 1921, was the first plant in northern Mexico to attempt the treatment of oxidized lead ores. From the milling point of view the many ores that have been treated at San Diego are very similar, the differences among them being rather of degree than type. Since 1921 the number of ores from different sources treated simultaneously has varied from four to eleven; in no case have any distinctive characteristics warranted the separate treatment of any of these. The zone of oxidation, source of the ores milled at San Diego, extends to a depth of 300 to 400 ft. below the surface. These ores carry more gold and less silver, lead, copper, and zinc than the underlying sulfide ores; the gangue minerals appear comparatively unchanged by oxidation and leaching. Lead occurs in diverse minerals, chiefly in cerussite, galena, and angle-site, the proportion of the lead in galena varying considerably in the different mines. An average of the feed to the mill would show the following approximate distribution of the lead content:

Jan 1, 1930

By NATHANIEI HERZ

(Cleveland Meeting, October, 1912.) THE formula very frequently used for computing the economical size of pipe to transmit compressed air is that of D'Arcy, as follows: d5(p1-p2)/w1l D-c w11 Where, D = the volume of compressed air delivered in cubic feet per minute,-at the final pressure. c = an experimental coefficient determined for the various sizes of pipe. d = the diameter of the pipe in inches. 1 = the length of the pipe in feet. P1 = the initial gauge-pressure in pounds per square inch. p2= the final gauge-pressure in pounds per square inch. W1 = the density of the air, or the weight in pounds per cubic foot at the initial pressure, p,. The most common case is that in which the given quantities are: the quantity of air required, the length of the pipe, and the initial pressure. The method of solution is to assume a pressure-loss and to compute the remaining factor, c/d5, thus giving the size of pipe corresponding to the assumed loss of pressure. It is always desirable to try two or more pressure-drops, in order to find the combination that is most satisfactory, since often a small change in the size of pipe will reduce or increase the loss of pressure several pounds. An alternative method is to assume a size of pipe and calculate the corresponding pressure-drop. Each method involves a series of tedious calculations to arrive at the most economical solution, and also requires the use of tables giving the constant, c, the actual diameters corresponding to the nominal pipe-sizes, the density of the air, w1, and often, for convenience, a table giving the

Dec 1, 1912

By John A. Prof. Church

ONE of the most striking phenomena connected with the mines on the Comstock lode is the extreme heat encountered in the lower levels. This heat is not due to the burning of candles, heat of the men, and decomposition of timbers, all intensified by bad ventilation, as was the case nearer the surface. It proceeds from the rock, which maintains constantly a temperature very much higher than the average of the atmosphere in Nevada. The heat of these mines is a matter of more than usual interest, for they are the only hot ones now worked in the United States, and both in the present temperature encountered and in the increase which is to be expected as greater depths are reached, they appear to surpass any foreign mines of which we have a record. Hot mines are known also in other countries, as in the tin and copper lodes of Wales, where one of the veins worked by the United Mines is known as the hot lode. It has springs which discharge water at a temperature of 116° Fahrenheit, the depth being 220 fathoms, or 1320 feet. The heat of the air in these workings is given at 100° to 113° Fahrenheit. The air is bad, and the heat in the drifts seems to be traceable to defective ventilation rather than to the real necessities of the case. Air is supplied through a small pipe, and is drawn from a place where the temperature is 95° Fahrenheit. Under such circumstances it is not surprising to read that in this hot mine the air is hotter than the rock, a state of things which I have never observed in the Comstock. Other mines have been reported to the British Coal Committee as having temperatures of 106° Fahrenheit and thereabouts, but the only positive comparisons that are available at this writing are the following, all from Cornish mines * Read by permission of Lieut. Geo. M. Wheeler, Corps of Enginerrs, U. S. Arm J, in charge of U. S. Geographical and Geological Surveys, west of the 100th meridian.

Jan 1, 1879

By E. P. Pfleider, D. H. Yardley

Layers of magnetic taconite of above average magnetic iron content extend down dip on the Mesabi Range to depths beyond the reach of open pit mining. A selected layer with thickness of 75 to 100 ft underlies many square miles. Such a selected layer can provide over 50 million tons of recoverable concentratc per square mile, at lower concentration ratios than in the present open pit taconite operations. The system contemplated would consist of large scale underground quarrying by a lane and pillar method. Working heights would be 60 to 100 ft; room widths, 50 to 75 ft; and productivity targets, about 40 tons per man-shift. The most critical problems would he roof control and blasthole drilling. The successful operation of large open pits and concentrating plants for treatment of magnetic taconites indicates that the basic techniques and economic problems of pellet production have been solved. The open pit reserves are large, but they are not necessarily available in sufficient quantity or quality to provide an adequate raw materials base for all potential producers. Furthermore, as the more easily available open pit crudes are used up, the pits will become deeper, stripping costs per ton of concentrate will increase, and recoveries will decrease as leaner crudes are utilized. The time will come when supplementary and replacement reserves of magnetic taconite will be required. One way these can be obtained is by underground mining of the down-dip extension of the Mesabi magnetic taconites, especially those layers averaging well over 25% recoverable iron. A key point in such a proposal is the possibility of realizing substantial savings by beneficiating an ore of 30% magnetic iron at 2.5 to 1 ratio of concentration. This contrasts with current practice in Mesabi commercial taconite plants, where the ore averages 22 to 25% magnetic Fe, with concentration ratios of about 3.0 when producing 61% Fe pellets. Two factors which favor the eventual development of underground taconite mining are: 1) the desirable physical structure and high grade of taconite pellets in general and 2) the improved engineering techniques in underground mining. Experience in large scale room and pillar mines demonstrates that, given strong rock strata immediately above a high grade mining

Jan 1, 1963

By J. B. Newkirk, D. L. Martin, A. H. Geisler, R. Smoluchowski

A FUNDAMENTAL investigation of the mecha-nism of the ordering reaction and of the accompanying changes in properties has been undertaken, since an extensive study of this process could well contribute to the knowledge of phase transitions in alloys. Cobalt-platinum alloys were chosen for the study since they exhibit interesting and unusual permanent magnet properties.1,2. In addition, the ordering reaction in cobalt-platinum alloys is a convenient one to study experimentally because of the high maximum ordering temperature, the large difference in the X-ray scattering power of cobalt and platinum atoms, and the relative ease with which the alloys can be plastically worked into wire and strip. In the early stages of this study, it became apparent that the published phase diagrams&apos;, &apos; of the cobalt-platinum system contained questionable features, in the region of 40 to 60 atomic pct Co, which were considered in another publication by the authors.4 That portion of the research reported elsewhere on the equilibrium states of cobalt-platinum alloys does not confirm the presence of a previously reported, high temperature disordered tetragonal phase and a low temperature body-centered cubic phase. On the other hand, the structure of the ordered phase is face-centered tetragonal with an atomic distribution analogous to that of CuAu.4 This lattice forms from the disordered face-centered cubic phase in such an orientation that the <100> directions are parallel to the <100> direc-tions of the disordered phase. At compositions other than the ideal 50 atomic pct the ordered phase can exist in equilibrium at high temperatures with the disordered phase. A Widmanstatten pattern of plate-like particles of the ordered phase parallel to (110) planes of the disordered matrix is observed when an initially disordered alloy is held at these temperatures. The temperature range of the two-phase region has been determined for three alloys by X-ray diffraction analyses, microscopic examination, and electrical resistivity measurements, and these results are incorporated with some of those of Gebhardt and Köster in the revised phase diagram of fig. 1. The purpose of the investigation reported here was to examine the mechanism of ordering in co-balt-platinum alloys by X-ray diffraction and metal-

Jan 1, 1951

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 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 E. E. Mason

The Canadian National Railway system is completing construction of the first major tunnel in North America to use the coarse-aggregate (+ ½ -in.) shotcrete technique of primary support and lining. The tunnel was driven 29 X 20 ft in cross section, 10,760 ft long, passing under an industrial and residential area of Vancouver. With the exception of 1400 ft in soil (mainly impervious tills), the tunnel passes through a very young series of flat-lying sedimentary beds, to a large extent so incompletely consolidated as to fall apart on exposure. For a conventional steel-support system, it was estimated 8 WF, 28-lb steel should be used at 5-ft centers. Cost of erection including lagging would amount to $120 per linear ft of tunnel at 304 per lb. With 8-in. concrete cover on the steel, lining would cost $280 per linear ft at $82 per cu yd. Thus, minimum cost of support and lining would have amounted to $400 per linear ft. It is now estimated that at least 90% of the rock tunnel would have required support and 100 % required lining. Specified shotcrete support was 6 in. in the arch and 4 in. in the walls. Cost of this work was roughly $100 per linear ft. In addition, another $10-$12 per ft has been incurred in drainage and waterproofing wet areas and in measures to correct experimental and operational errors, thus finalizing the support as a lining (Fig. 1). The tunnel was driven three shifts five days weekly, no blasting being allowed by city ordinance between midnight and 7.00 a.m. A six-drill jumbo was used to drill a 10-ft round, 110 holes blasted three times daily. A 2-in. layer of shotcrete was applied to the newly blasted arch commencing within 45 min of blasting. This was done from a flying deck that extended over the muck pile from the jumbo (Fig. 2). Also during the mucking cycle, the preceding incomplete arch support was brought up to 6-in. specification. The walls were sprayed 4 in. thick during the drilling cycle (Fig. 3). The shotcrete machines and aggregate bins were mounted on the jumbo.

Jan 1, 1970

By Reinhardt Thiessen

Under sulfur in coal, is usually understood that form of sulfur which is combined with iron and known as pyrite. It occurs in the form of balls, lenses, nodules, continuous layers, thin sheets, or flakes, both in horizontal planes and vertical cleavage fissures. But pyrites also occur as very fine microscopic particles, or nodules, disseminated through the compact coal. This form has had but very little consideration. Finally, there is sulfur in coal in an amicroscopic form (not visible with an ordinary microscope), probably combined with the organic matter that exists in the coal. This form has had considerable attention from a scientific standpoint, but has probably not been recognized enough on the economic side. One or the other, or both, of these two latter forms may comprise the larger part of the sulfur content of coal, especially after it has been washed or otllerwise prepared for use. Pyrites in Microscopic Particles All coals that have been examined by the author contained a varying amount of sulfur in very small globules, or particles, of pyrite. These particles are seen in a thin [section as roughly rounded opaque dots, Figs. 1 to 10. When isolated, they are generally shown to be approximately spherical in shape, with a rough outer surface. They vary in diameter from a few microns to a hundred microns, the majority messuring from 25 to 40 microns; relatively few exceed the latter diameter. They are, therefore, very small objects. Their size is best appreciated by comparing the illustrations, in which they are shown. at a magnifiea tion of 100 diameters, with some known area like the period used in the ordinary printed page. The period is about 0.6 mm. in diameter, and . when magnified 100 times, will cover a circular area of about 2 1/2 in. in diameter, or all but the corners of the illustrations. The illustrations, therefore, represent an area about as large as an ordinary period, and the pyrite globules form but a small part of the total area. Very frequently a number of these particles are joined together in horizontal rows; oc-

Jan 1, 1920

By Fred Bond

THE process of comminution by grinding is properly classified as an art, rather than as a science. Like most other operations concerned in ore dressing, or in the treat-ment of nonmetallic minerals, the mathe-matical relationships of rock breaking are still obscure, and much disputed. If some basic formula exists, comparable for in-stance to E = RI in electricity, it has not yet been placed in common use. The absence of such a comprehensive mathe-matical background undoubtedly is the cause of many inefficient designs and installations, as well as of much poorly oriented experimental work. On the other hand, the mathematical immaturity of the process constitutes an opportunity for a real contribution on the part of those who enjoy mental pioneering. Some of the statements made in any such exploratory work may be little more than opinions, and it is to be expected that some will later be proved untrue; but such an evolutionary development is necessary if we are ever to arrive at the fundamental laws, the discovery of which can change the empirical art into a mathematically exact science. The most significant principle of com-minution that we possess is probably Rittinger&apos;s law, which states that the work done in crushing or grinding is proportional to the area of the new surface produced. There is an alternative theory, known as Kick&apos;s law, which formerly was preferred to Rittinger&apos;s but which now is rather dis-credited. According to Kick, the work done in comminution is proportional to the volume, or weight, of the pieces broken, or to the cube of their diameters, while accord-ing to Rittinger it is proportional to the square of the diameters.

Jan 1, 1940

By C. A. Heiland

FOR the past three years, the senior writer has carried out, with inter-ruptions, a series of investigations into the characteristics of prospecting seismographs of a wide variety of construction. Early in 1932, a com-plete equipment was developed for both refraction and reflection observa-tions; its first function being, however, the application in reflection shooting. The performance of the equipment proved to be highly satis-factory in a series of field tests&apos; which were carried out by the junior writer, whose services were loaned to the Colorado School of Mines by courtesy of the Plains Exploration Co. in Denver. The various problems that were encountered in the construction of the equipment, in its application in the field, and in the interpretation of the results, are fully treated in Publication 47 of the Department of Geophysics of the Colorado School of Mines. Its first part deals with the various problems encountered in the design of the instruments, and presents a discussion of such topics as the free and forced oscillations of damped and undamped mechanical seismographs, the action of oscil-lographic recording instruments and amplifiers, the characteristics of electromagnetic seismographs, and the requirements of damping, natural frequencies and static magnification for the pickups, amplifiers and oscillographs used in refraction and reflection seismographs. Further-more, a detailed discussion of the various methods of static and dynamic tests of seismic receivers, and a description of the reflection equipment developed at the School of Mines is presented. Unfortunately, a delay has occurred in the publication of the first part of this investigation concerning the instrument problems. There-fore, the second part, dealing with the field problems, is herewith pre-sented first.

Jan 1, 1933

By J. A. Fulton, A. B. Foote

Gold was discovered in the Sierra Nevada by J. W. Marshall on Jan. 2, 1848. The town of Grass Valley soon sprang up and contained several stores in 1849; but the population of the town has always reflected the fluctuations in quartz mining. Gold-bearing quartz was found on Gold Hill in September 1850, and in the next two years most of the quartz-bearing veins in the vicinity were located. At first, the quartz was crushed in mortars with spring poles; the IIuff Co. took out $20,000 in this manner during the winter and spring of 1851. The first mill was put up in January, 1851. In 1866, there were in Grass Valley 248 stamps, crushing 71,420 tons of ore with an average yield of $30 to $35; in Nevada City, there were 142 stamps, crushing 14,200 tons, with an average value of $25. Rut in 1918, only two properties in this region, the Empire and the Korth Star, were producing Since then, there has been a revival of mining in the district and the following properties are being opened up: The Golden Center. Grass Valley Gold Mines Co.. Idaho-Maryland Mines Co., while the Su1tana is kept unmatered and work is going on in a half dozen mall propertics Mining Claims At the first meeting of miners in Grass Valley, Jan. 13. 1851, a plot :30 by 40 ft. was allowed for a claim, the boundaries in all cases being perpendicular. In 1852, the quartz miners in Nevada County deeided that "each prospector shall hereafter be entitled to 100 ft. on a quartz ledge or vein and the discoverer shall be allowed 100 ft. additional. Fach claim shall include all the dips, angles, and variations of the vcin." This rule was in force until replaced by the Federal mining laws of 1872; these allowed quartz claims to be 1500 ft along the vein, with all the dips, spurs, and angles, and to have a width of 600 ft. The holdings of the principal companies consist of these early patented mining claims; standard claims, as authorized by the Act of 1872, both patented and unpatented; agricultural tracts, both patented and

Jan 1, 1927

By Howard Lee

I. GEOLOGY AND ORE OCCURRENCE IN central Colorado is a great belt of intrusive porphyry nearly 100 miles long (160 km.), extending from the Clear Creek district on the north to Aspen on the south, which includes many of the well known mining camps of the State. Near the southern end of this belt, at Leadville, the occurrence of these intrusives is most marked, resulting in intensive mineralization and the formation of a great variety of large orebodies. During the past 40 years, Leadville has been a steady producer of gold, silver, lead, zinc, manganese, iron, and bismuth, in the forms of sulfid, carbonate and oxide ores. It is the purpose of this paper to discuss pyrite alone, which, under present economic conditions, is valuable chiefly for its sulphur contents. The ore-bearing formation of the Leadville district consists of two beds of limestone separated by a layer of quartzite. The upper limestone is carbonaceous, and is known locally as the blue limestone. It varies in thickness from 50 to 300 ft. (15 to 91 m.). The lower limestone is Silurian, known locally as white limestone, and is about the same thickness as the upper bed. Underneath the Silurian limestone is a layer of Cambrian quartzite front 100 to 250 ft. (30 to 76 in.) thick resting on Archean granite, which forms the limit of ore deposition. As a rule, there is a sheet of white porphyry above the upper, or blue limestone; a sheet of gray porphyry is associated with the blue limestone, either in or below it, but the porphyries are not so regular as the quartzites and limestones and are not always found in their expected positions. Throughout the district there is an elaborate system of faults and intrusive porphyry dikes, which have all important bearing on ore deposits. The writer has seen two or three orebodies which were not closely associated with either a fault or a porphyry dike, but if the minor fractures and water courses are considered as part of the fault system it is safe to say that all orebodies are directly traceable to one or both of these causes.

Jan 8, 1918

By L. R. Jackson, W. T. Lankford, K. F. Smith

ComMercial steel sheet is prepared by a combination of hot and cold rolling and annealing. This treatment usually results in more or less pronounced anisotropy. The anisotropy may manifest itself both as preferred orientation and in the manner in which impurities, segregations, and the like, are aligned in the sheet. The type of preferred orientation and the organization of impurities or segregations may affect the elastic moduli, the yield strength, the tensile strength, and almost always the amount of ductility in different directions. In any case, the most important directions concerned in the anisotropy are along the rolling direction, along the width direction, and along the thickness direction. Considerable data exist on the anisot-ropy of sheet steel as demonstrated by conventional tensile tests; however, few attempts have been made to measure the constants of plastic anisotropy and use them to describe the flow of anisotropic sheet under combined stresses. In this paper, evidence is presented indicating that plastic flow in anisotropic sheet can be described by the shear-strain energy flow theory provided that the anisotropy is properly taken into account. Materials Used in the Investigation Table I lists the sheet materials used in this investigation and describes the condition in which materials were tested. Direction, of Tests and Test Methods Two types of tests were run—tensile tests and hydraulic-bulge tests. Characteristic parameters of anisotropy were determined from the tension tests by methods which will be described later. In all cases, the tensile test pieces were cut from the same quarter line and adjacent to the bulge test pieces in the sheet in order to minimize

Jan 1, 1949

By Theron Wasson

Michigan reports another record year. Its production of 18,605,000 bbl. exceeds any previous year&apos;s total and is 2,000,000 bbl. over 1937, the previous record year. Production in 1938 brings the accumulated total for the state to a little over 100,000,000 bbl. It has taken 14 years to reach this accumulative figure, which would meet the needs of our country for about one month. Twelve new oil and gas fields were opened in 1938 and 978 tests for oil and gas were completed, of which 566 were oil wells, 25 gas wells and 387 dry holes. The new oil discovered is probably about equal to the oil produced during the year. Activities in 1938 The Temple field, Clare County, was the discovery of the year. Since July, 46 wells have been completed, and although not yet outlined it appears that more than 2000 acres have been proved for production from the Monroe of Devonian age, at a depth of 3900 ft. This discovery is the result of a wildcat test along a trend northwestward from the older fields of the central basin. The Edenville pool, Midland County, ranks second among the new fields. Thirty-five producing wells have been drilled to the Dundee at 3800 feet. The surprise development was in southwestern Alichigan, Allegan and Van Buren Counties, where six new Traverse lime pools were opened with a daily production of about 8000 bbl. at the end of the year. This is the first consistent Traverse production in the state and is about 100 miles southwest of the producing areas of the central basin. These fields have had a rapid development because of the shallow depths, which range from 900 to 1500 ft. Bloomingdale, Van Buren County, had a town-lot boom, and 72 wells have been drilled there since August 1938. Small operators from many states have been attracted to this shallow territory, and the coming year will see much drilling in these and surrounding counties. The Buckeye field, Gladwin County, led the state in amount of oil produced. Its total of over 7,000,000 bbl. was far ahead of that of any other pool.

Jan 1, 1939

By Theron Wasson

Michigan reports another record year. Its production of 18,605,000 bbl. exceeds any previous year&apos;s total and is 2,000,000 bbl. over 1937, the previous record year. Production in 1938 brings the accumulated total for the state to a little over 100,000,000 bbl. It has taken 14 years to reach this accumulative figure, which would meet the needs of our country for about one month. Twelve new oil and gas fields were opened in 1938 and 978 tests for oil and gas were completed, of which 566 were oil wells, 25 gas wells and 387 dry holes. The new oil discovered is probably about equal to the oil produced during the year. Activities in 1938 The Temple field, Clare County, was the discovery of the year. Since July, 46 wells have been completed, and although not yet outlined it appears that more than 2000 acres have been proved for production from the Monroe of Devonian age, at a depth of 3900 ft. This discovery is the result of a wildcat test along a trend northwestward from the older fields of the central basin. The Edenville pool, Midland County, ranks second among the new fields. Thirty-five producing wells have been drilled to the Dundee at 3800 feet. The surprise development was in southwestern Alichigan, Allegan and Van Buren Counties, where six new Traverse lime pools were opened with a daily production of about 8000 bbl. at the end of the year. This is the first consistent Traverse production in the state and is about 100 miles southwest of the producing areas of the central basin. These fields have had a rapid development because of the shallow depths, which range from 900 to 1500 ft. Bloomingdale, Van Buren County, had a town-lot boom, and 72 wells have been drilled there since August 1938. Small operators from many states have been attracted to this shallow territory, and the coming year will see much drilling in these and surrounding counties. The Buckeye field, Gladwin County, led the state in amount of oil produced. Its total of over 7,000,000 bbl. was far ahead of that of any other pool.

Jan 1, 1939