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By E. Mcl. Tittmann

Deep-seated human instincts urge us to positively mark the passage of time. We celebrate the passage of each year. Years give way to decades, and decades to half centuries and centuries. At all these mileposts we are inclined to pause, take a look around and catch our breaths before embarking on the next leg. We are at such a point now and this meeting I am sure will give direction to the road ahead into the decade of the seventies. In looking around at this point, 1973, it is obvious to all of us that the environment in which we must mine, mill, smelt and refine lead and zinc has radically changed. These changes have, of course, occurred over a long period of time. They have, however, all been in the same general direction. They have all had the same motivation. The period of greatest contrast is probably the fifteen years just before World War II and the fifteen years following the end of that war. I thought that I might review briefly with you what seems to me to be four of the more important changes that have developed since World War II that profoundly affect our activities in the lead and zinc industry. I mentioned before that all these changes have been in the same direction; that is, they have all tended to restrict our freedom of action in pursuing our objective of producing lead and zinc on a competitive basis at a profit. Consequently, in discus- sing them you may think that I am merely viewing with alarm. This is not the intent. This is merely supposed to be an objective analysis. I think it appropriate before discussing these trends in de- tail to examine the position of lead and zinc today.

Jan 1, 1970

By W. Kauenhowen

The production of petroleum in Germany during 1932 totaled about 1,608,558 bbl., a slight increase over the 1, 602,517 bbl. produced in 1931. A decline, as shown in Table 1, occurred chiefly in the Volkenroda (Thuringia) field. The total production of the other fields (salt domes), however. reached a new record, about 21 per cent above 1931. Table 1.—Oil Production of Germany by Fields and Oil Provinces, 1928-1932 (Barrels of 42 Gallons)" Salt Dome Province __________________________________________________|_________________________________________________________________________________________________________________________ 1928 274,323 322,742 679 46,319 644,021 644,315 1929 310,891 337,582 10,535 67,578 719,901 720,069 1930 586,404 427,539 100,716 72,485 1,186,969 29,806 1,220,296 1931 506,548 403,634 213,549 116,088 1,242,598 360,885 1,602,517 1932 769,405 366,982 230 979 130,711 1,498,077 110,481 1,608,558 " Official figures published in Germany are given in metric tons. For the above conversion into barrels a factor of 1 metric ton equaling 7 barrels has been used. Includes a very small production from Hcide, Holstein. c Includes a very small production from Tegernsee, Bavaria, and Bruchsal, Baden. Nienhagen-Hanigsen Field In 1932 the Nienhagen-Hanigsen yielded about 51 per cent of the production from the four German salt dome fields. During 1932 the productive area was again extended, chiefly towards the northwest in the so-called north district, to which the present drilling activity is confined almost entirely. Since the discovery of the north district in 1928, about 45 wells have been drilled in it, of which only two were

Jan 1, 1933

By J. W. Pugh, Sam Leber

Single crystals of tungsten were made and deformed in tension at 3000°C. The slip traces so formed on these crystals were analysed to determine the apparent slip system. Results indicate that deformation occurs in the<III> direction on planes of maximum shear stress. This determination agrees with the early work of Taylor and Elam on other body-centered cubic crystals at lout temperatures. SLIP in face-centered cubic and hexagonal close-packed metals has consistently manifested itself in straight traces which indicate that glide takes place on planes of highest atomic density and in directions of closest packing. The slip traces observed on body-centered cubic metals are, on the other hand, frequently branched and wavy, and indicate that while glide takes place in the direction of closest packing, it does not necessarily choose the plane of highest density. The early work of Taylor and Elam1 4 indicated that glide took place in the close-packed direction on planes close to those defined by the maximum shear stress. Subsequent investigations have tried to rationalize these observations in terms of an elementary process on the close-packed planes (110). For example, Elam5 and Grenin~er&apos; have suggested alternate glide on nonparallel (110) planes with the observed result that the summation of these glides results in a trace which defines some plane other than{110). Madden and chen7 have recently reviewed the phenomenological and theoretical aspects of noncrystallographic slip. More recently Koehler&apos; has presented a model of dislocation propagation which permits another rationalization. He indicated that dislocation loops are transferred from one glide plane to another by double cross-slip of screw segments. It is reasonable to assume that, on the average, such transfers may result in a trace which approaches the plane of maximum shear stress. The work described in this paper will show that

Jan 1, 1961

By Samuel Hoyt

THIS paper gives a brief description of an investigation made several years ago on the diffusion of zinc into copper. The material for that study was furnished in the form of thin copper strips coated with zinc. The result was required rather quickly and at not too great an expense, and especially information was desired as to the rate at which zinc would diffuse from the zinc coating into the copper and the temperature at which the operation should be carried out. A study of the requirements of this problem indicated that the solution might be secured by means of six determinations. This is the smallest number that will give the information desired and, at the same time, furnish checks on the accuracy of the determinations which justify an abbreviated experimental program. This does not count a preliminary test which was designed to give some idea of the correct temperature to use. The minimum number of temperatures that can be used is two. Knowing the rates of diffusion of zinc into copper at two properly chosen temperatures, it is possible to calculate the rate for any other temperature, and also to check the accuracy of the determination by means of the heat of diffusion, which is calculated from the effect of temperature on the rate of diffusion. The minimum number of determinations at any one temperature is three. The amount of diffusion which occurs at a fixed temperature is definitely related to the time of diffusion, so that by determining the amount of diffusion for three different time intervals, this relationship may be established and possibly a check on the accuracy may be secured. This accounts for the six determinations or experiments, and suggests the logical plan of the work. The check used here is not generally applicable to diffusion phenomena, but it seems to hold closely enough for the limited amount of diffusion in this investigation to justify its use.

Jan 1, 1928

Mr. Cottrell : I omitted to speak of the cost of installation. The precipitation-plant at the Balaklala smelter, up to the time of initial operation, including the construction of flues, installation of the apparatus, etc., cost $107,000, and subsequent modifications probably represented at least $15,000 more. Upon the information gained in this plant, the installation at the cement-mill, handling nearly twice as much gas, has been reduced in cost in a number of ways, but the overhead construction, carrying the precipitator at the top of the stacks, is naturally expensive, yet, even so, the total cost of construction will probably not greatly exceed $150,000. The mechanical details of the tubular form last shown have been worked out more recently than those of the plate form, and the tubular form promises to be still less expensive in construction, as you would naturally expect. The cost of operat-ing the plant varies somewhat with the character of the gases used. The amount of power consumed is not determined by the tonnage of the material collected, but by the volume of gas to be handled. It takes as much power to precipitate a thin cloud as a dense one. In the cement-plant they are getting a higher efficiency; i. e., a greater number of cubic feet treated per kilowatt than in the earlier plants. This is perhaps partly due to higher temperature of the gases, which here average about 450° C. The best figures on the cement-plant are between 3 kw. and 4 kw. Of

Jan 1, 1913

By George W. Bain

SOME problems concomitant with commercial exploitation of marble are presented as examples of interesting, useful and profitable fields for application of scientific knowledge. The marble industry is only one such field and is selected because its varying new aspects are familiar to the author. However, what is true for marble is equally so in principle for many industrial minerals. The problems of any stone industry are to maintain markets, create new outlets for stone already in demand, and develop varied uses for varieties that are not so popular. Here the geologist has a different role from most of his colleagues in metal mining. The producing branch may ask about the expectable variation in thickness or size of a deposit as development proceeds. The stock department may call for the available amount of a given type of stone before accepting a large order. The sales force requires data on the use for stone from certain parts of deposits in order to divert grades to the most suitable use. The service department wants defects rectified and the cause determined to avoid recurrence. The mills want data on durability and cutting quality of abrasives. The geologist occupies no special department; he is on general call, as may be illustrated by a few types of problems that may be classified as: (1) dominantly geological in character, (2) dominantly chemical in character, (3) dominantly physical in character. GEOLOGICAL PROBLEMS The geological problems deal almost exclusively with the size of blocks. Size across the deposit is limited by thickness of individual beds, and along the strike by the space between crosscutting joints. Frequently the vertical depth of a block is reduced by exfoliation shells arising from spontaneous expansion. All these factors require consideration in developing a deposit to fill an order. Thickening of Marble Beds The limestone beds that became the marble deposits of the northern Appalachians and of the Yule locality in Colorado were seldom homo-

Jan 1, 1940

AN extremely successful meeting, under the joint auspices of the Ohio Section and the Iron and Steel Committee, was held at Cleveland on April 19 and 20, about one-half of those in attendance being from the Cleveland district and the other half from a distance. The morning session on April 19, C. K. Leith presiding, was opened by the presentation of the ad-dress of which an excerpt is printed on the opposite page. In the subsequent discussion R. A. Allen pointed out that the meeting had not been called "to blow the lid off the tariff" since that is only one of the many problems connected with the wisest utilization of man-ganese, and it was the purpose of this meeting to con-sider all those interdependent problems. The purpose of the tariff was to develop an adequate domestic sup-ply, and that result had not been accomplished. An-other important problem, linked with the tariff, is the need for assuring, while we are at peace, an adequate war supply of manganese, and at present this country has no such policy. D. F. Hewett said that his 3-months&apos; trip in Europe last summer had impressed him with the fact that England had once been in the position United States now is in, of being the principal world&apos;s producer of all the more important minerals and with a declining reserve had gone on a free-trade basis. No one pointed out that, with the exception of tin, the present relative position of England is due more to an increase in pro-duction in other countries, rather than to a decrease of domestic production. J. Sharshall Grasty referred to recent development work-in Virginia where of 30 per cent easily concen-trated manganese ore about 300,000 tons has been blocked out and possible and probable ore amounting to 700,000 tons more is indicated.

Jan 5, 1927

By T. R. Cass, M. R. Achter

A technique for measuring the creep and rupture strength of nickel specimens bonded by sintered oxide layers has been developed for the investigation of the role of grain-boundary oxide in the oxidation strengthening of nickel during creep at 817 °C. Prom the inverse dependence of the rate of bonding on the thickness of the starting oxide, it is suggested that the rate of diffusion of Ni++ through NiO is the controlling process at the start of sintering. Cornparisons of the creep and rupture strength and of the microstructure of sintered couples with conventionul creep specimens suggest rupture in nickel is prevented by load-bearikzg, ikltergranular layers of oxide. A number of recent investigations have shown that at high temperature and low stress the creep-rupture strength of nickel and nickel-base alloys may be much greater in air than in an inert gas or vacuum.&apos;-7 For example, at 817°C and 2500 psi, nickep failed in vacuum in 48 hr but not in air after 4000 hr, and a Ni-Cr-A1 alloy5 at 1038°C and 3000 psi failed in vacuum in 4 hr but not in air after 731 hr. Fig. 1 is a typical creep curve in air for materials experiencing this pronounced environmental strengthening. A common feature of these curves is the entry into a third stage of accelerating creep, concurrent with the for-

Jan 1, 1962

By John Pew

PRIOR to the development of the bulk-oil carrier, practically all transportation of oil was in barrels and in cans contained in wooden cases; the latter was known as case oil. In the year 1885, approximately two hundred million gallons of petroleum were exported from this country in barrels and about one and three-quarter millions in bulk; less than twelve years later, the shipment in barrels had decreased to nearly one and three-quarter million gallons, while the transport of bulk oil had increased to four hundred eighty-four million gallons. The first modern tanker, the "Glückauf," was built in England in 1886. Her hull, which was 300 ft. long, was divided into compartments by transverse bulk-heads, these compartments being divided by longitu-dinal center-line bulkheads extending throughout the oil spaces. There was a pump room forward of the boiler room, thus providing a cofferdam or safety space. Between the main and upper decks, a narrow trunk extended the full length of the&apos; oil spaces, the trans-verse and longitudinal bulkheads being carried to the upper deck. This allowed for the expansion of the oil from a rise in temperature, and if the tank below the main deck was kept full, the danger of the oil moving with the roll and pitch of the vessel was considerably reduced. Spaces for the carriage of light oil were provided on each side of the vessel outboard of the expansion trunk, while water ballast was carried under the machinery compartments fore and aft. Although vessels previously had been built to carry oil next to the skin of the ship, it is claimed that the "Glückauf" was the first one constructed on the new principle outlined.

Jan 12, 1922

By Henry Howe

(New York Meeting, October, 1913.) The Equilibrium. Position of A 1.-Some of the most important data on this subject are collected in Table I. Definition of Ae 1-Just as we call A 1 of rising temperature Ac 1, and that of falling temperature Ar 1, so we may give the symbol Ae 1 to the equilibrium position of A 1. Preliminary Assumptions.-In deciding what weight to assign the various data, and indeed what data are to count, three assumptions should be made. These are: 1. The corollary from the phase rule, that the temperature of Ae 1 is constant and independent of the carbon content, though, of course, it may be changed by the presence of other elements. 2. That because neither in heating nor in cooling can the transformation begin before the temperature reaches Ae 1, though it may be delayed by lag till after the temperature has passed beyond Ae 1, therefore Ae 1 should be at or below the observed beginning of Ac 1 and at or above the observed beginning of Ar 1, and, a fortiori, it should be at or below the observed maximum of Ac 1, and at or above the observed maximum of Ar 1. It may be necessary to take these maxima into consideration in view of the experimental difficulty of detecting these beginnings.

Jan 6, 1913

By W. J. McKenna

THE International Smelting Co. concentrator at Tooele, Utah, first operated on a custom basis for the treatment of lead-zinc-iron ores on Nov.&apos; 1, 1924, with a capacity of 500 tons per day. On May 1, 1925, the capacity was increased to 1000 tons per day by the addition of another 500-ton section. The concentrator has since operated on the two-section basis, each treating 500 tons per day entirely by flotation. LABORATORY AND TEST MILL In connection with the concentrator, a well-equipped laboratory and small continuous testing plant are maintained. The flotation equipment in the test plant is of both the Callow and Mineral Separations Sub-"A" types, so that actual concentrator conditions may be duplicated as closely as possible. PURCHASING OF ORE A new shipper usually sends to the plant a 25 to 50-lb. sample, representative of the ore to be shipped. Batch flotation tests are made on this sample to determine its amenability to the concentrator treatment flowsheet and reagent combinations. The results of these tests, which are accurately correlated with those obtained at the concentrator, both as to grades of products and recoveries, determine the actual value of the ore as submitted in the ore purchasing department&apos;s treatment schedule. Hearty cooperation has existed at all times between the ore purchasing and operating departments in the selection of ores as concentrator feed. ORE TREATED The basic tonnages for mixtures on the two sections come from the Park City and Bingham mining districts. The Park City tonnages are received by rail and consist of crude ores and gravity mill products. Those from the Bingham district are received by rail and aerial tramway,

Jan 1, 1928

By Joseph E. Pogue

New economic forces are at work in the petroleum industry. In order to visualize these forces and to see clearly their bearing upon the producer, refiner, and marketer, it is necessary, first, to go back and gain a perspective of the economic evolution of the business. Early Trend to Integration For several decades prior to 1911, the outstanding feature of the petroleum industry was a trend toward integration, culminating in a huge combine, the Standard Oil Co. An important aspect of this integrative trend, however, was its concentration upon a combination and control of refining and marketing, leaving crude oil production, for the most part, to the exigencies of small-unit competition. It is a noteworthy coincidence that during this era the law of oil and gas was formulated and applied, whereby these substances had to be reduced to possession to establish ownership; and the forces of competition in crude oil production were thereby intensified. It was to the interest of an industry, safeguarded in its control of manufacturing and markets, to have supply stimulated by legal convention as well as by individual initiative in order that the growing demand could be met without interruption. And so overproduction of crude oil during this era was no handicap, but rather an aid, to the progress of the industry. Disintegration But the idea of superintegration, despite its efficiencies, became repugnant to the temper of the times and so the Standard Oil Co. was dissolved by Court decree—disintegrated into over 30 parts. And thus, in 1911, was ushered in the second era of the petroleum industry, a period of intense competition. This era coincided with the development of automotive transportation, and a tremendous growth resulted in the effort to keep pace with the mounting demand for gasoline. An intense individualism and unbridled competition were appropriate to this period of entry

Jan 1, 1930

SINCE I promised you above when speaking of the melting of metals to teach you to make small crucibles and shells for melting, I do not wish to fail in my promise. For, in truth, since they are instruments that are much used for this procedure, they increase the work if they are not good, and often cause great extra expense as well as necessitating repetition of the work. If they are good they save everything. Therefore, if you have to make them, do it so that they, are greatly aided by art. It is first necessary to have the clay of a good nature, that is, resistant to the force of the fire by its own natural virtue, either when it is lean or when its viscousness is mixed with much talc, and whether it is yellow or white. This should be well freed from small stones and beaten well with an iron, and then thoroughly mixed by hand. With this should be mixed an eighth part of finely ground and sifted iron scale,* and also some [145] young ram&apos;s-horn ashes. These things should be well mixed together by hand and by beating them. If this clay should not be strong enough by itself, it is mixed with another lean clay, with crushed peperino, flintstone, or some other stone that in your judgment seems to be arid and resistant. Crucibles are worked on a low potter&apos;s wheel turned by hand, or on a high one turned by foot, just as plates are made. Both large and small ones are made. Most of them are given a triangular shape at the mouth, and the shells have a kind of spout for ease in pouring out the metal. This done they are well dried, and baked in furnaces like pots or other vessels. At the end, when they have been thus made they are used for melts.

Jan 1, 1942

W. L. Saunders, New York, N. Y. (communication to the Secretary*):—The Laramie tunnel, though a small one, compares very favorably in the speed of driving with the great Alpine tunnels which have the record so far. I think it safe to say that, taking all things into consideration, the record made at Laramie is the best American record, though it still falls short of the long-tunnel records abroad. In discussing tunnel-records it must always be borne in mind that there are conditions peculiar to each individual tunnel job, so that no comparisons are complete, fair and conclusive. At Laramie there is one point which stands out prominently, and which distinguishes this from any of the recently-built Alpine tunnels, and that is that here we have great progress in an American driven tunnel without the use of a carriage for mounting the drills. At the Arlberg and Loetschberg tunnels, the carriage was an essential condition for progress. All the heading-drills were mounted upon a bar which rested upon a small carriage. This carriage was withdrawn after the drilling and run into the heading after the blast without much disturbance of the drills, and with very little adjustment except that required in jacking the horizontal bar across the tunnel. The carriage was so small in its track-area that it required little mucking to run it in to the face; and as the rock-drills used were heavy machines 38 in. in diameter, progress in setting up and drilling was very much accelerated by the use of the carriage. At the Laramie tunnel hammer-drills were used instead of piston-drills, and here we have an important distinction which

Jan 1, 1913

By C. E. Arnold

THE CHAIRMAN (PERCY G. BECKETT, Globe, Ariz.).-When you are at Miami tomorrow, you will see a very interesting comparison on the surface of the two mining methods that are being employed there largely. In the case of the surface over the Inspiration mining method, you won&apos;t see very much left of the surface. Everything has gone down. In the case right at the line of the Inspiration ground and the Miami, you will see that the surface over the top slicing which the Miami company has been doing in that country has been riding down evenly and uniformly; and it gives a very marked comparison of the two types of mining, and, to a certain extent, of the different degrees of waste dilution. I would ilke to hear from Mr. Maclennan on this subject. F. W. MACLENNAN, Miami, Ariz.-A paper based on percentage extraction by shrinkage stoping is a difficult one to discuss for the reason that it is hard to arrive at extraction figures until a section has been completely mined out. In the Miami mine we are using a method of shrinkage stoping with narrow stopes and pillars. This ore has been completely broken up and we have started in at the far end to draw off the ore mass maintaining the top of the broken ore dipping at an angle of 60° away from the direction in which we are retreating. A very important point I think about drawing a large. mass of ore down at an angle rather than trying to maintain the top of the ore more or less horizontal is that drawing at a steep angle has a tendency to create a horizontal movement in the ore mass as well as the vertical movement of the ore traveling down to the drawing off chutes. We know that this takes place, on account of the horizontal movement of marked

Jan 12, 1916

By W. A. Mudge

ONE of the most prominent features of our present-day industrial development is the ever-increasing demand put upon materials of con-struction. Engineering ingenuity, within the past 25 years, has been unusually active, and in some fields at least engineers frankly say that engineering design has progressed as far as the limitations imposed by the properties of the present materials of construction will permit. Consequently, they are today demanding improvement in their working materials and seeking new ones, through the aid; of which the present limitations of design may be overcome. The activity of this search is evident in all fields, but it is particularly so in that of structural materials required to be resistant to corrosion. The corrosion resistance of metals and alloys is never absolute and all-inclusive; a particular alloy will withstand some corrosive conditions well and fail utterly tinder others. Furthermore; other properties, physical and mechanical, required in-conjunction with corrosion resistance vary considerably for different commercial applications. One wants a soft, ductile sheet metal resistant to atmospheric corrosion; another, a high-strength- alloy resistant to sulfuric acid. The last decade has witnessed active and definite progress in the development of high-strength, corrosion-resisting alloys. In June, 1924, a symposium by the American Society for Testing Materials, on Corro-sion-Resistant, Heat-resistant and Electrical-resistance Alloys, disclosed no less than 60 commercial alloys the properties of which were described as being suitable for industrial service where corrosion resistance

Jan 1, 1935

By R. Fahn

Bentonites are best suited for the preparation of acid activated clays with efficient adsorption properties. They are weathering products of acid volcanic ashes and natural deposits are spread worldwide. The main constituent of bentonite is aluminum hydrosilicate montmorillonite with a high ability to swell. Physical and Chemical Properties of Montmorillonite The clay mineral montmorillonite is named after its place of discovery, near Montmorillon in southern France. The structure of this clay is shown in [Fig. 1]. The montmorillonite crystal consists of about 15-20 silicate plates. Each silicate plate is composed of three layers. The central one is formed by aluminum or by ferric hydrate octahedrons, the two outer ones consist of silicon dioxide tetrahedrons. In the presence of water, the montmorillonite crystal swells and water molecules become deposited between individual silicate layers. Two types of natural bentonites are known: the Western type, which is a natural sodium bentonite (high swelling grade), and the Southern type, an alkaline earth or calcium bentonite (low swelling grade). Southern bentonites have efficient adsorption properties of their own. They are called natural active earths or fullers earths. Acid Treatment of Bentonite Under the influence of a mineral acid, the exchangeable alkaline earth ions of bentonite are substituted by hydrogen ions. Moreover, depending on the acid concentration, temperature, pressure, and reaction time, a more or less pronounced leaching process takes place. Thereby Al-, Fe-, and Mg-ions are extracted from the octahedron layers. This results in a change in the crystalline structure of montmorillonite and in an increase of its specific surface area and porosity, as shown in [Fig. 2].

Jan 1, 1983

By Paul Billingsley

The Georgetown mining district is located in Deerlodge county, Mont., about 20 miles west of Anaconda. It lies along the divide between the headwaters of Warm Springs creek, draining eastward, and Flint creek, flowing west and north through the Philipsburg valley. The actual divide is formed by Cable mountain, a narrow ridge running north and south, terminating to the south in low hills overlooking Georgetown lake, and to the north in a high, rugged plateau that falls off to the west to the wide valley of Flint creek. On the eastern, or Warm Springs, slope of Cable mountain is the Cable mine, with the Hidden Lake mine a few miles north. On the western slope is the Southern Cross group, with smaller mines, the Twilight, Cincinnati, Red Lion, and Big Bill, at intervals to the northward. The Georgetown mines lie in the hills south of Cable mountain; the Philipsburg mines, of which the Granite Mountain, Bimetallic, Hope, and Trout are the chief, form a separate group to the north, overlooking Flint Creek valley and Philipsburg. (See Fig. 1.) The region ranges in elevation from 5,000 to 9,000 ft. It is, with the exception of the lower valleys, well timbered with small fir and pine, although Cable mountain and the higher summits to the northward rise slightly above timber line. The main valleys have the smooth contours of glaciation, and their mouths are frequently choked with morainal deposits. General Geology. In a very general way the valley of Flint creek coincides in this region with the boundary between the pre-Cambrian slates of western Montana and the folded Palaeozoic rocks of the Rocky Mountain system. The great limestone formations of the Carboniferous and Devonian, lying at flat dips, extend from Anaconda well toward the head of Warm Springs creek, but on the divide the Cambrian appears, closely folded and intruded

Jan 1, 1914

By B. H. Sage, W. N. Lacey, W. M. Morris

The volumetric behavior of isobutane at temperatures below its critical temperature has been studied by several investigators. Seibert and Burrelll measured the vapor pressure of isobutane from the ice point to the critical temperature. Dana and co-workers2 determined among other thermodynamic quantities the density of the saturated liquid and the saturated gas and the vapor pressure from approximately 0 to 130 F. Sage and Lacey3 studied a number of the thermodynamic properties of this hydrocarbon from 70" to 250" F. The specific volume in the gas and liquid region was determined at pressures up to 3000 Ib. per sq. in.? throughout this temperature interval. In addition, the vapor pressures were measured at 30" intervals. These data taken together serve to establish the thermodynamic behavior of isobutane at temperatures between 0" and 250" F. with reasonable accuracy. However, apparently there are no data available at the higher temperatures. For this reason an investigation of the volumetric behavior of isobutane at temperatures between 100" and 460" F. was carried out with apparatus that has been described in another paper (p. 136, this volume). Materials The isobutane used in this investigation was obtained from the Philgas Division of the Phillips Petroleum Co. That company&apos;s special analysis upon this sample indicated it to contain less than 0.03 mol per cent of impurities. In order to avoid traces of noncondensable gases, this hydrocarbon material was subjected to two successive fractionations at a high reflux ratio in a column approximately 4 ft. long and % in. in diameter, which was packed with small glass rings. The middle portion of distillate from the first fractionation was used in the second fraction-ation and a portion of the overhead from this second distillation process was repeatedly condensed at liquid-air temperatures at a pressure only slightly above the sublimation pressure of isobutane at this temperature.

Jan 1, 1940

By George A. Bell

THE mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic conditions are ideal except for a three months rainy season. The company generates its own power for mining and milling operations with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The company also furnishes free living quarters, hospitalization and work- men&apos;s compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands. HISTORY The Demonstration ore body was worked by the Igorots for many years, as evidenced by old stopes and fill encountered in present operations. Attention of Americans was first attracted soon after the Spanish- American war. During the building of the Benguet road to Baguio, the engineers and foreman became interested in the geology of the district.

Jan 1, 1939