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By James K. Gluck, William E. Galloway, Gary E. Smith, John P. Morton, Christopher D. Henry

INTRODUCTION Surface mining and in situ leaching of uranium have the potential to alter ground-water quality around mines and leach sites. Of particular concern is the fate of uranium and its associated trace elements: molybdenum, arsenic, and selenium. We wish to under- stand the natural processes that control trace element concentrations in ground water and how these processes will influence dispersion of the elements from a mineralized zone, both naturally and during and after mining or restoration. For example, it is commonly recognized that the trace elements are soluble in oxidizing ground water but are insoluble, and can be precipitated, in reducing ground water. Thus oxidizing, metal-bearing water leaving a deposit could re- enter reduced ground, causing the water to be re- reduced and the trace elements to be, reprecipitated. In a sense, this is recreating the original mineralization process. To accomplish the above goals, we have (1) examined the theoretical controls of concentrations based on the available geochemical and thermodynamic data, (2) determined the major ion composition and oxidation-reduction status of Oakville waters because of the influence of these factors on trace element solubility, and (3) determined trace element concentrations and distribution in Oakville ground water. The last approach is used to evaluate how well actual behavior follows predicted behavior. This report focuses on two elements, uranium and molybdenum, because they exemplify the results obtained. The report also is restricted to a regional study of Oakville ground water. Results of more de- tailed study in and around major uranium districts in the Oakville and much of the raw data that support the conclusions in this report are presented in Galloway, Henry and Smith (1980). This report is part of that larger study, which concerned the depositional systems, hydrology, and geochemistry of the Oakville. The U.S. Environmental Protection Agency funded the study, under grant numbers R-805357-01 and R-805357-02. Theoretical controls were determined by reviewing the available literature on aqueous chemistry and behavior of uranium and molybdenum. To aid in under- standing water chemistry, Oakville water analyses were run through a modified version of the computer model WATEQF (Plumer, Jones, and Truesdell, 1976). WATEQF calculates speciation of dissolved ions and determines saturation with respect to a variety of minerals. In the discussion below, ion activity products (IAP) are compared with the equilibrium constant (KT) for various reactions and mineral products. Values of log IAP/KT near zero indicate that the water is in equilibrium with a mineral. Values less than -1 indicate considerable undersaturation and values greater than +1 indicate oversaturation. Galloway, Henry, and Smith (1980) give a more complete discussion of the application of this approach to Oakville water chemistry. Eh-pH diagrams have been constructed or adapted from the literature to predict what form -- dissolved ion or stable mineral species -- uranium and molybdenum assume under various conditions. Construction of the diagrams has followed procedures described by Garrels and Christ (1965). This approach is particularly appropriate because the solubility of the elements is Eh-dependent, and Eh varies greatly within the Oakville aquifer. A number of assumptions or approximations are inherent in the use of Eh-pH diagrams and chemical models such as WATEQF and in the interpretation of water chemistry in general. Both Eh-pH diagrams and chemical modeling rely entirely upon available thermo- dynamic data, including free energies of formation and dissociation constants for various reactions. These values are known to varying degrees of accuracy. Most major ions and minerals are relatively well control- led; however, data for trace metals are much poorer. Thermodynamic data are not available for some minerals, and for other minerals, two or more divergent values exist. By necessity, we have relied on the judgment of others to evaluate thermodynamic data. Calculations by WATEQF and constructions of Eh-pH diagrams are based on an assumption of equi1ibrium. Equilibrium may not be comnon in low-temperature aqueous environments; at best, ground-water composi tion may be in a state of dynamic equilibrium, continuously changing due to changes in environmental conditions. Eh-pH diagrams show what phases are stable at equilibrium under given conditions; they do not prove that the phases actually exist. Many minerals persist or form metastably under conditions outside their equilibrium stability field. The kinetics of reactions, which cannot be evaluated here, are important in determining what phases occur. Kinetics may be less of a problem for ground water that travels and evolves slowly through a semihomogeneous matrix than for many other natural systems. Eh-pH diagrams show equilibrium fields only of phases included. They do not indicate anything about stability relative to phases not included in the diagram. WATEQF, obviously, cannot calculate the degree of saturation of a mineral not included in the program or for which the appropriate ions were not analyzed. Thus, a mineral that was not considered may be the most stable phase under a given set of conditions and may control the solubility of a trace element. Also, this study is limited exclusively to in- organic compounds. Organic material is known to be an

Jan 1, 1980

By J. D. Miller, J. E. Sepulveda

Tar sand deposits in the state of Utah contain more than 25 billion bbl of in-place bitumen. Although 30 times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion bbl). Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water separation process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique. Experimental results with an Asphalt Ridge, Utah, tar sand sample indicated that percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage. These variables were identified by means of an experimental factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence' gathered in this investigation seems to indicate that a hot-water separation process for Utah tar sands would allow for the efficient utilization of this important energy resource. The projected increase in the ever-widening gap between the domestic energy demand and the domestic energy supply for the next few years has motivated renewed interest in energy sources other than petroleum, such as tar sands, oil shale and coal. Although a number of research programs on the exploitation of national coal and oil shale resources have already been completed, very few programs have been initiated on the processing of tar sand resources in the United States. In recognition of their significance as a domestic energy resource, investigators at the University of Utah have designed an extensive research program on Utah tar sands. An important phase of this program, and the main subject of this publication, is the development of a hot-water process for the recovery of bitumen from Utah tar sands, as a preliminary step toward the production of synthetic fuels and petrochemicals. The term "tar sand" refers to a consolidated mixture of bitumen (tar) and sand. The sand in tar sand is mostly a-quartz as determined from X-ray diffraction patterns. Alternate names for "tar sands" are "oil sands" and "bituminous sands." The latter is technically correct and in that sense provides an adequate description. Tar sand deposits occur throughout the world, often in the same geographical areas as petroleum deposits. Significantly large tar sand deposits have been identified and mapped in Canada, Venezuela and, the United States. By far, the largest deposit is the Athabasca tar sands in the Province of Alberta, Canada. According to the Alberta Energy Resources Conservation Board (AERCB),2,3 proved reserves of crude in-place bitumen in the Athabasca region amount to almost 900 billion bbl. To date, this is the only tar sand deposit in the world being mined and processed for the recovery of petroleum products. Great Canadian Oil Sands, Ltd. (GCOS) produces 20 million bbl of synthetic crude oil per year. Another plant being constructed by Syncrude Canada, Ltd. is expected to produce in excess of 40 million bbl of synthetic crude oil per year. According to the Utah Geological and Mineral Survey (UGMS), tar sand deposits in the state of Utah contain more than 25 billion bbl of bitumen in place, which represent almost 95% of the total mapped resources in the United States.4 The extent of Utah tar sand reserves seems small compared to the enormous potential of Canadian tar sands. Nevertheless, Utah tar sand reserves do represent a significant energy resource comparable to the United States crude oil proved reserves of 31.3 billion bbl in 1976.5 Tar sands in Utah occur in 51 deposits along the eastern side of the state.4 However, only six out of these 51 deposits are worthy of any practical consideration (Fig. 1). As indicated in Table 1, Tar Sand Triangle is the largest deposit in the state and contains about half of the total mapped resources. Information regarding the grade or bitumen content of Utah deposits is still very limited. The bitumen content varies significantly from deposit to deposit, as well as within a given deposit. In any event, the information available6-8 seems to indicate that Utah deposits are not as rich in bitumen as the vast Canadian deposits which average 12 to 13% by weight.9 Although many occurrences of bitumen saturation up to 17% by weight have been detected in the northeastern part of the state (Asphalt Ridge and P. R. Spring), the average for reserves in Utah may well be less than 10% by weight. Separation Technology As in any other mining problem, there are two basic approaches to the recovery of bitumen from tar sands. In one

Jan 1, 1979

By K. A. Jackson, J. D. Hunt

A new classification of eutectics is proposed, based on tlze entvopies of wzelting of the tuio eutectic phases. The clnssification was used to predict suitable tvansparent analogs of the metallic systems. Experimental confir?nation loas obtained for the theovetical shape of the lamellar solid-liquid interface, fov the fault mechanisms of lanzellar spacing changes, and for the development of low-energy solid-solid boundaries between the lamellae. An explanation is presented to account jov the irvegular and coinplex regular structures zrhich are found in some eritectic systems. FrOM experimental observations, single-phase materials can be divided into two groups according to their solidification characteristics, those that grow as faceted crystals and those that do not. acksonl' showed from thermodynamic reasoning that the type of growth depended on a factor a which was almost thg entropy of melting. Most nonmetals have high entropies of melting (a greater than 2) and grow with crystalline facets. Most metals have low entropies of melting (CY less than 2) and grow almost isotropically with no facets. The authors propose that eutectics may be classified in a similar manner. There are three groups of eutectics, those in which both phases have low entropies of melting, those in which one phase has a high and the other phase has a low entropy of melting, and those in which both phases have high entropies of melting. Lamellar or rodlike structures are formed in systems in which both phases have low entropies of melting. In these alloys dendrites of either phase may be formed, when the alloy is rich in the relevant component. Examples are Pb-Sn, Sn-Cd, Pb-Cd, Sn-Zn, Al-Zn. Irregular, Fig. 14((), or complex regular, Fig. 14(b), structures are formed in alloys in which one phase has a high entropy of melting and the other has a low entropy of melting. Examples are A1-Si, Zn-MgzZnll, Pb-Bi, Sn-Bi. When the alloys are rich in the low entropy of melting phase, dendrites are formed; when the alloys are rich in the high entropy of melting phase, faceted primary crystals are produced. These crystals are sometimes called hoppers or pseudodendrites. In this work the term dendrite will only be used to describe nonfaceted primary crystals. Dendrites are not formed during solidification in high entropy of melting single-phase materials. The third group of eutectics includes alloys in which both phases have high entropies of melting. Each phase grows with a faceted solid-liquid interface. Since most metals do not have high entropies of melting, metallic examples in this eutectic group are rare. However they may occur between some intermetallics and semiconductors or semimetals such as silicon, germanium, and bismuth. Attempts have been made to study eutectic solidification visually by watching the growth process.374 Since metals are not transparent, the observations had to be made on external surfaces. This difficulty can be overcome by using transparent analogs of the metallic systems. As was mentioned earlier, most single-phase compounds have entropies of melting greater than 2 and so grow as faceted crystals. Recently organic materials with entropies of melting less than 2 were investigated.' These materials grow in exactly the same way as the low entropy of melting metals. When the materials are pure, they grow with a solid-liquid interface parallel to an isotherm; when they are impure, cells or dendrites are formed. Since these materials are transparent, have low melting points, and even have cubic structures, they should be ideal for making up transparent analogs of the metallic eutectics. The purpose of the present work was to investigate these organic eutectics and to see whether this quite different series of eutectics could be classified in the same way as the metallic systems. The observations made on the organic alloys are also discussed with reference to the current theories of lamellar growth. Explanations are proposed to account for the structures formed in the other eutectic groups. EXPERIMENTAL Thin cells containing the organic alloys were uni-direction ally solidified on a specially constructed microscope stage.' Uniform growth rates were obtained by moving the cells, with a motor drive, through a fixed temperature gradient, so that the solid-liquid interface remained stationary with respect to the microscope objective lens. The cells were made by fusing two microscope cover slides 7/8 by 7/8 by 1/100 in. together on three sides, leaving a gap of 1 to 3 mils between the slides, and these were filled by surface tension. A preliminary investigation of the phase diagram between two components could be made very rapidly. One side of the cell was filled with component A and the other side with component B. Since only a small amount of mixing could occur every composition from pure A to pure B was present in the cell. When the cell was placed in the temperature gradient a pictorial representation of the phase diagram was obtained. Eutectics, peritectics, "interorganics", and solid -solid transformations could be readily detected. Fig. 1 shows part of a eutectic phase diagram. The Sample was first grown slowly then stopped. The two

Jan 1, 1967

By Sidney H. Haughton

FOLLOWING the discovery of diamonds in 1870 and the Witwatersrand gold fields in 1886 South Africa changed from a predominantly pastoral country with a scattered white population into a land whose economy came rapidly to be based primarily on mining. The total value of the mineral output of the Union in 1944 was approximately $493,000,000, to which gold contributed 84 per cent. Gold furnished some 33 per cent of the Union Government's total revenue in that year, and approximately half the country's population obtained its livelihood directly or indirectly from the gold mining industry. In any review of the Union's mining activities and in any consideration of the country's future, gold mining must occupy a prominent place. It is generally conceded that the present structure is not properly balanced and that an economy based on a preponderance of a single nonpermanent factor possesses potentialities of serious instability.

Jan 1, 1946

By AIME AIME

THE week, of April 5 will long be remembered by those that attended the Birmingham meetings of the Open-Hearth and Blast Furnace committees of the A.I.M.E. Iron and Steel Division. Birmingham iron and steel own received the 450 delegates with open arms; described and discussed their southern metallurgical practices and problems and compared experiences with their northern brother metallurgists in two days of technical sessions on Wednes-

Jan 1, 1937

By George C. Bravner

WITH the great expansion currently being made in the aluminum output of the United States, not only by the company that has heretofore been the sole producer but by a now organization in the field it is only natural to wonder to what degree the; ore reserves of the United States can contribute to the growing consumption. For the three-year period 1937-'39 the U.S. Bureau of Mine's figures indicate that the annual domestic production of bauxite averaged about 370,000 long tons, compared with average, annual import of about 194,000 long tons. About 85 per cent of the imports came from Surinam, nearly all of which went into aluminum manufacture. Not all of the or -kipped from mines in the United States is used to make alumimun however as Bureau figures indicate that in these three years an average of only 48 per cent of the domestic ore shipment were so used the abrasive chemical and other industries taking respectively 27, 21, and 4 per cent of the output. The recent increase in the demand for bauxite has been of course in it use for aluminum manufacture. This as is well known is largely attributable to the world race for supremacy in

Jan 1, 1941

By John Birkinbine

(New Haven 'Meeting, February, 1909.) AWAKENED public interest in efforts to conserve natural resources will certainly be appreciated by the members of the American Institute of Mining Engineers, and a discussion upon conservation may well form a part of one of the Institute meetings, for the records of papers and discussions which appear in the 38 volumes of its Transactions are replete with evidence of effort's in this direction. Every process which reduces the fuel consumed or the power applied per unit of product; every utilization of waste material, or employment of that formerly rejected, to obtain something of value ; every feature of construction or operation which lessens the labor required or increases the output per employee, is an advance in the direction of true conservation. This may not appear from the records of late conferences or from published articles, in which the effort seems to be concentrated upon reducing the consumption and presenting to the people of the country estimates of exhaustion of natural resources. I rejoice in the awakening of public interest in a matter so important for the present and future welfare of our nation; I appreciate the possibility of much good following conferences of the Governors and delegates from various States and from national societies; and I recognize the interdependence, not only of different States, but of contiguous nations. In fact, the marvelous development of transportation by land and by water, and the decreasing rates at which commodities can be moved great distances, have in many cases practically obliterated geographical boundaries, and nearly every country on the globe can either market its product in other lands or draw upon them for raw or manufactured materials ; hence, conservation is an international subject.

Apr 1, 1909

By Robert T. Chapman

The revolution in equipment for blasthole drilling, ore loading, and ore hauling has been so rapid over the last ten years that it has generated an important new profit potential in the mining industry. With the new high-capacity machinery now available, it is possible for a mining enterprise to earn a profit from larger and lower grade orebodies than ever before despite the ever-increasing burden of rising costs. Just what such equipment can accomplish when coupled with improved mining practice has been demonstrated with startling success at the No. 1 mine of Minerva Oil Co. near Cave-in-Rock in Hardin County, Ill. The No. 1 is an underground operation which has been producing fluorspar and zinc ores and concentrates continuously since 1944. A few years ago, when the mine neared the familiar cross-roads where rising costs, increasing tonnages, and relatively static product prices converge, company officials decided to bolster the operation with new mobile equipment. They chose three machines which proved so effective that output at the No. 1 doubled between 1963 and 1965,while costs dropped by about 40% in the same period.

Jan 11, 1966

The industrial might of the Bowen Basin is primarily the result of Utah Development Co.'s work- which has opened up the Blackwater, Goonyella, Peak Downs, and Saraji mines; built the Hay Point port; and is now developing the Norwich Park mine.

Jan 1, 1977

By Kefton H. Teague

Attempts to locate domestic supplies of sillimanite have been unsuccessful until recently. This paper describes recent discoveries of sillimanite-bearing schists in the Southeastern States, with emphasis on geology of the deposits, mineral composition, origin, and reserves. Statements concerning possible methods of mining, milling, and utilization of sillimanite are given. Results from refractory tests on a laboratory scale are summarized.

Jan 1, 1950

By William B. Plank

ENROLMENT data given in this report of the seventh study of the schools by the Mineral Industry Education Division reveals the critical situation in the mineral engineering schools of the United States. Complete figures for the year 1942-43 show that at that time, about one year after Pearl Harbor, the enrollment of mineral engineers was 6385 or 30 per cent less than in 199441. By October 1943, however, enrollment had dropped to 2050, as reported in the Journal of Engineering Education of January 1944. This was a further reduction of 68 per cent in one year, or 77 per cent in three years. With accelerated programs in effect during the current year, with many graduations since last October, and with the military forces taking practically all the high school graduates, the present enrollment is, of course, much lower than the 2050 above given. There are no late data on the exact situation. In Canada, the same situation exists in the mineral engineering schools, only

Jan 1, 1944

By E. P. JENNINQS

(Cleveland meeting, October, 1912.) LARGE deposits of titaniferous iron-ore occur at Caribou, an old silver-mining camp in Boulder county, Colo., 17 miles west by south of Boulder, and a few miles northwest of the tungsten-mines. Professor Regis Chauvenet 1 published a part analysis of the ore many years ago, but gave no description of the wall-rock. Caribou hill, which contains both the silver-bearing veins and the iron-ore deposits, is a low dome of gabbro surrounded by the Archaean schists and gneisses of the Front range of the Rocky mountains, the peaks of which, a few miles west of Caribou, attain an elevation exceeding 12,000 ft. The gabbro stock is roughly elliptical in outline, with approximate diameters of 1 and 3 miles. The crest of the dome is 10,500 ft. above sea-level, and the town and ore-deposits are 500 ft. lower. Outcrops of the iron-ore occur in the town and extend NW. for 2,000 ft., where they disappear under the swampy meadows of Caribou park. Portions of the deposit are covered by drift, but one continuous outcrop is 900 ft. long and from 200 to 250 ft. wide. A second deposit is 0.25 mile south of the town along the eastern slope of the hill. It is not as well defined as the north bed, but is approximately 1,000 ft. long and from 100 to 200 ft. wide. The easily disintegrated ore does not form prominent outcrops, but the outlines of the deposits are readily traced by the large amount of ore fragments that cover the ground. Trenches and pits sunk on the outcrop expose a roughly banded magnetic iron-ore, with pyroxene as the principal gangue-mineral. The Gabbro. This rock was classified in the field as a gabbro from the presence of pyroxene and striated feldspars, and for convenience the field-name will be retained. 1 Chauvenet, Regis, Biennial Report of State School of Mines, Golden, Colo., p. 16 (1886).

Oct 1, 1912

By IRVING H. WENTIVORTII

(New York Meeting, February, 1912.) THE little town of San Nicolás, Tamaulipas, Mexico, lies approximately 60 miles east of Linares, situated in the State of Nuevo Leon, and 150 miles SE. of Monterey, as shown in the sketch-map. Fig. 1. The place is reached from Monterey by the Tampico train as far as Linares, a distance of 92 miles, and then by coach the rest of the way. It is situated in a narrow valley between low hills, the houses forming one main street and a plaza. It is peopled by about 500 inhabitants. The climate is temperate, the thermometer ranging from 90° in summer to a few degrees below freezing-point in winter; but this severe weather only lasts a day or two at a time, when the " northers " blow. There are no streams in the vicinity, but water sufficient for the use of the people is obtained from wells. The rainfall is about the same as that in the rest of NE. Mexico. The rainy months are July, August, and September. The rest of the year is practically dry, with an occasional showery day or two during the winter, when a " norther " is blowing. Timber is abundant in many localities. There are two varieties of oak, besides mesquite, ebony, "maguira," "patol," and a number of other kinds of trees indigenous to this region. I. HISTORY. On the discovery of the silver-lead hearing veins occurring in this district, the mining-camp of San Nicolás was founded in 1767 by the Spaniards, and numerous mines were opened and worked for a distance of abort 3 miles east and 5 miles west of the town. At the western extremity and near the Carrolena mine, a small town called San Pedro was built. The ruined walls of the houses form a single street, and all is over-

Aug 1, 1912

By W. S. Ayres

I. Introduction. This cavern was discovered Oct. 32,1904, by Mr. Charles 8. Deutschman, in company with whom I made, May 29 to June 3,1905, at the request of Mr. Howard Douglas, Superintendent of the Canadian National Parks, the first exploration of it for the Canadian government. The results were stated in a paper, orally presented, with lantern-views from my photographs, at the British Columbia Meeting of the Institute, Victoria, B. C., July 5, 1905.* The present paper embodies also the results of a second examination, made Oct. 25 to 29, 1905. The accompanging map, Fig. 1, will serve as a guide to the following description. 11. Location. The cavern is situated at snow-line, at the head-waters of Cougar creek, on the west slopes of the Selkirks, about 2 miles north from Ross Peak water-tank, and 5.5 miles west from Glacier station, on the main line of the Canadian Pacific Railway. It was then reached by an arduous climb from the water-tank, up the ravine of Cougar creek, for 8,000 ft. (2,000 ft. of altitude) over rock- and snow-slides, and through a thick tangle of alders. But an easy and very picturesque trail has, during the past summer, been opened by the government from Glacier station, which is also a hotel of the railway company. Figs. 3, 3 and 4 represent views, not heretofore published, of the grand scenery of this region, so rapidly becoming the object of attraction to thousands of tourists from all parts of the world. These views, as well as those shown in Figs. 5, 6, 7, 8

Jan 1, 1908

By C. R. Kuzell

GEOGRAPHICAILY the industry of reducing and refining of copper continued to migrate from the .United States during 1931. While this country is losing the predominant position of its copper industry, our engineers still enjoy their pre-eminent position as leaders in the design and operation of the new plants being brought into production in the four quarters of the globe. Progress in the art, as indicated by the construction of the recently completed works, has not been revolutionary. Standard methods have been followed, augmented by novel features in flow-sheets demanded by the results of progress in the art of ore-dressing, and by reason of problems incidental to the peculiarities of the new ores being treated. Design and construction progress has likewise been orderly and without radical departure from less recent practice; new features in primary and secondary equipment being logical developments to provide for special conditions to keep abreast of improve¬ments in accessory apparatus. The new plants are being rapidly brought in without hazardous novelties and for the purpose of yielding the principal ingredient, copper, in as large a volume as it will he possible to market; the old United States procedure. In the meantime the domestic plants are shut down or operating at a very low capacity, threatened with untimely demise unless the metallurgist can extract and develop other valuable products from the ores. International agreements .and tariff protection may be a temporary reviving stimulant, but for many mines the days of profit will be numbered unless the ores can be made to yield as values the ingredients now being discarded. Invisible progress in this direction has been made during the past year, and it is to he hoped that time will prove that the outstanding progress of 1931 was in the development of processes for the ultimate recovery of by-products from copper ores, perhaps even relegating the value of the copper yield to secondary importance.

Jan 1, 1932

By GUY C. RIDDELL

THE recent purchase by an American investment trust of a substantial block of shares in a British owned Venezuelan copper operation directs attention to mining activities that have been quietly gaining momentum in that country for a number of years. We hear so much of oil work in Venezuela that attention to its metal-mining activities is in most quarters casual. In gold and copper the country has made some interesting mining records, and two of the old districts are ,digging in for a come-back. Copper Copper production centers in the state of Yaracuy. The Aroa-Cumaragua mining region has had a long and eventful history. The Aroa mine itself, 50 miles from the coast in West-Central Venezuela, was discovered in 1605. First mined in 1632, owned at one time by Simon Bolivar, it has been reopened many times and is now , the basis of substantial operations by the South American Copper Syndicate, Ltd. of London. The latter has operated the property profitably, off and on, for a number of years, paying heavy dividends on a small investment-at times over 300 per cent annually.

Jan 1, 1929

By R. E. Boni, G. Derge

Application of surface tension measurements has been made to molten silicates in order to determine the effect of sulphur upon the surface tensions of synthetic blast furnace slags. In melts with the same molar ratios of AI2O3 + SiO2 to the basic oxides BaO, CaO, and MgO, the surface tensions increase in the order of oxides listed. Sulphur lowers the surface tensions of the basic BaO, basic CaO, acid BaO, acid CaO, and acid MgO slags in that order; and the concentration of excess sulphur at the slag surface increases in this same order of slags. The rate and amount of desulphurization of iron by these slags is favored by a low excess surface sulphur in the slag. IN a previous paper,1 the authors discussed the applications of surface tension measurements of molten silicates to problems of metallurgical interest. Of major importance is the aid that such studies lend to forming a working concept of slag structure. Since the ability of a slag to desulphurize metal depends strongly upon its composition,2"4 fundamental information about the structural differences between various slags which contain sulphur should aid the development of better desulphurizing media. For that reason, the present investigation concerns the effect of sulphur upon the surface tensions of synthetic blast furnace slags. Experimental Procedure , The maximum bubble-pressure method was used to measure the surface tensions of synthetic blast furnace slags in the temperature range 1300° to 1600°C. The method is based upon the equation which was developed by Schrödinger5 from a consideration of the forces of hydrostatic pressure and surface tension of a liquid which oppose bubble formation when a gas is forced through a tube immersed in the liquid. where y is the surface tension between argon and slag in dynes per centimeter; g is the gravitational constant, centimeters per second2; H is the manometer reading in centimeters; s2 is the density of manometer fluid in grams per cubic centimeter; S1 is the density of the medium in grams per cubic

Jan 1, 1957

By William R. Chedsey

ALTHOUGH few changes can be reported in educational methods at the mineral technology schools during 1940, other events have taken place of direct interest to, and that will have a profound effect upon, mineral industry education on the United States. In the erection of new buildings, some notable changes have been made on the campus, The U.S. Bureau of Mines Experiment Station at the University of Utah, Salt Lake City, was dedicated on May 20. The construction and equipment of this building cost between $300,000 and $400,000. It will be the general headquarters for the metallurgical division of the Bureau and will have a pronounced effect upon the mineral industries research program at the University.

Jan 1, 1941

By A. KROENLEIN

THE Cromwell 'Pool has been the outstanding development in Oklahoma during the year 1924. . Tonkawa contributed the deep "Slick Sand" bit apparently its 'peak has been reached and like other pools producing from below the Mississippi lime its decline' mill be rapid. After reaching a daily production of 67,000 bbl., the Cromwell Pool is declining because of a lull in -new completions, but a mile extension has revived activity and an area equal to that of the present producing' area is under development and will cause an increase in the present production of 38,000 bbl. This pool is seven months old, has three dry holes in one hundred twenty completions and is actually defined only on the southern extremity. This area has been one of the chief contributors to the .over-production of high gravity oil in the Mid- continent fields and will be such' for the remainder of ' the year. 1924 and first part of 1925.

Jan 1, 1924

By Charles R. Holmes

MORE than 70 igneous pipes and dikes are known to occur in Cambrian sediments throughout an approximately circular area of about 75 sq miles in southwestern Ste. Genevieve County and southeastern St. Francois County, Mo., across the southern portion of the Farmington anticline, which is outlined in fig. 1. From evidence obtained from fossil fragments taken from some of the intrusive, and from the similarity in composition of the more basic intrusives to those of known age in surrounding states, these pipes and dikes are believed to be at least post-Devonian and probably Cretaceous in age. As first postulated by Rust, these intrusives are believed to represent explosion tubes, or diatremes, punched through great thicknesses of solid rock by gaseous pressure. The particular intrusive studied is located about 1 mile north of the small town of Avon at an elevation of 880 ft in the EM SES NE% of sec. 2, T. 35N, R. 7E. Outcrop is through the Bonneterre dolomite in two separated exposures. The larger outcrop extends east and west for about 50 ft along a tributary in a small ravine (fig. 2). The smaller exposure occurs as a few scattered patches over an area 20 ft square about 100 ft to the north. The area between the exposures is covered, but scattered patches of the Bonneterre dolomite outcrop throughout the area surrounding the diatreme. Where exposed, contact relations show the surrounding dolomite to be shattered and metamor- phosed to a fine-grained rock for a distance of 15 to 20 ft from the intrusive. The igneous rock occurs as a dark greenish-gray porphyry near the center of the diatreme and as a fine-grained, greenish-gray material containing lapilli and metamorphosed fragments of dolomite near the contact with the country rock. The most abundant original mineral of the porphyritic rock is olivine now largely serpentinized as the result of extensive hydrothermal alteration at time of emplacement. The most common constituent of the fine-grained rock, which occurs near the border of the intrusive, is calcite. Mica is a common constituent of both types of rock, occurring as tufts or

Jan 1, 1950