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By Gerard Matthes

WITHIN the last three years, aerial mapping has made wonderful progress. Its three sources of development in North America may be enumerated as follows: (1) The work of the U. S. Army Air. Service and Corps of Engineers at the McCook Experimental Field, Dayton, Ohio. This is generally regarded as the backbone of this class of endeavor in the United States. (2) In Canada, a great deal has been accomplished in a practical way by methods that have not even been tried out in the United States. Under the leadership of the late Doctor Deville, the Dominion Land Surveyors have turned out reconnaissance maps of large areas at very, small cost. (3) Private capital has contributed a great deal toward development of aerial mapping in a practical way in the United States. Prominent in this regard stands the Fairchild Aerial Surveys, Inc. which has spent large sums in research and development work, especially in the construction of aerial cameras. Its camera is, at present, the official camera of the U. S. Army and Navy Air Services, also, of the Canadian and Brazilian governments. Aerial photographic surveying is a flexible process and adapted to a variety of uses. To date, it has proved. of direct practical value for engineering projects such as reservoir and power transmission surveys, railroad location, drainage, harbor front studies; also, for many commercial purposes, tax assessment, city planning, forest surveys, and lawsuits. In a few instances, aerial photographs have been used successfully by geologists as base maps on which to record field observations, thereby dispensing with pacing and compass surveys. There is reason to believe that, eventually, the aerial map will find wide application in the work of geologists. The reason for advancing this opinion is that aerial maps have, in other fields, proved more complete as regards detail than maps made by standard processes of surveying and drafting, and often are more accurate than the latter. At the present time, five distinct uses are being made of aerial photographs: There is the "oblique" photograph taken at an angle with the horizon; it is used extensively for illustrations in newspapers, magazines, and advertisements. Also, for reconnaissance purposes, it has been found of great practical value. For illustrating reports of engineers and geologists, it offers many obvious advantages. In the Canadian Surveys, maps have been compiled from oblique photographs.

Jan 3, 1925

By Howard J. Smith

For several years this Institute has recorded in its Transactions the various discoveries of potash‡ in America, and the successive stages in the development of an independent domestic potash industry. This paper is intended primarily to continue the record through the year 1935. In retrospect it is not inappropriate to note that public interest aroused in 1910 resulted in the production of some 1090 tons of pure potash in 1915, as a small beginning in the domestic inorganic potash industry, and that the infant industry thus begun reaches its majority this year, following a record production in 1935 of about 600,000 tons of potash salts and exports to no less than 22 foreign countries, including six countries in Europe. This production, with an estimated 200,000 tons of pure potash, may be compared with a production in 1934 of 430,157 tons of salts with an equivalent of 144,342 tons of pure potash. Mine and Plant Improvement During 1935, the American Potash & Chemical Co., at Searles Lake, Calif., began to reap the benefits of its previously enlarged plant facilities, which increased its productive capacity to 180,000 tons of muriate annually. The United States Potash Co., at Carlsbad, N. Mex., improved its operations by installing trolley locomotives and other haulage facilities and is maintaining its development headings two years in advance of operations, with projected plans for orderly mining for years to come. The hoisting shaft at its mine is now equipped to hoist at the rate of 1,000,000 tons annually, and the refinery to produce 150,000 tons of muriate containing less than one per cent of impurities. The Potash Co. of America, at Carlsbad, N. Mex., completed the conversion of its plant from a prospecting to an operating basis late in 1935. The coarse-crushing plant, with a capacity of 150 tons an hour, formerly on the surface, was installed underground, with ore pockets

Jan 1, 1938

By Howard J. Smith

For several years this Institute has recorded in its Transactions the various discoveries of potash‡ in America, and the successive stages in the development of an independent domestic potash industry. This paper is intended primarily to continue the record through the year 1935. In retrospect it is not inappropriate to note that public interest aroused in 1910 resulted in the production of some 1090 tons of pure potash in 1915, as a small beginning in the domestic inorganic potash industry, and that the infant industry thus begun reaches its majority this year, following a record production in 1935 of about 600,000 tons of potash salts and exports to no less than 22 foreign countries, including six countries in Europe. This production, with an estimated 200,000 tons of pure potash, may be compared with a production in 1934 of 430,157 tons of salts with an equivalent of 144,342 tons of pure potash. Mine and Plant Improvement During 1935, the American Potash & Chemical Co., at Searles Lake, Calif., began to reap the benefits of its previously enlarged plant facilities, which increased its productive capacity to 180,000 tons of muriate annually. The United States Potash Co., at Carlsbad, N. Mex., improved its operations by installing trolley locomotives and other haulage facilities and is maintaining its development headings two years in advance of operations, with projected plans for orderly mining for years to come. The hoisting shaft at its mine is now equipped to hoist at the rate of 1,000,000 tons annually, and the refinery to produce 150,000 tons of muriate containing less than one per cent of impurities. The Potash Co. of America, at Carlsbad, N. Mex., completed the conversion of its plant from a prospecting to an operating basis late in 1935. The coarse-crushing plant, with a capacity of 150 tons an hour, formerly on the surface, was installed underground, with ore pockets

Jan 1, 1938

By W. E. Bruce, R. J. Morrell, James Paone

This chapter is a partial summary of an investigation by the U.S. Bureau of Mines (USBM) made in response to a recent request by the Assistant Secretary, Water and Power Development of the U.S. Department of the Interior, for a comprehensive review of horizontal boring technology related to underground power-line installation. This review is concerned primarily with 3 to 36-in. diam horizontal holes from several hundred to several thousand feet in length. An electric power system consists of three essential functions: generation, transmission, and distribution. The generation component includes the generating station and step-up substation; the transmission component includes the transmission line and stepdown substation at typical voltage levels ranging from 69 to 345 kv for underground lines and 69 to 500 kv for overhead transmission lines; the distribution component includes the distribution line carrying the commonly used voltages of 120, 208, and 240 v, the distribution transformer, and the line to the service customer.l The Federal Power Commission reports that 1600 miles of underground transmission lines of 60 to 345-kv capacity are now in service in the United States. By 1980, it is estimated that approximately 3000 miles of trans- mission lines will have to be placed underground.2 The cost of burying electric transmission lines underground in metropolitan areas, approximately 30 miles from the center of each of the most populated cities, will exceed $1.5 billion with the methods now available. The wide spread in unit costs of overhead and underground transmission lines narrows as right-of-way costs for overhead transmission in congested areas increase. Improved methods of underground emplacement will certainly reduce this difference in costs and even further favor underground emplacement. Also, in the future, overhead transmission lines will probably not be permitted in highly built-up areas.

Jan 1, 1970

By E. DeGolyer

The only known direct method of discovering oil deposits is by the drilling of test wells. Such exploration is always hazardous and generally very costly. The problem of the prospector, therefore, is to select test sites that are favorably located and so to reduce the odds against his venture. Early in the history of the oil industry, it was realized that oil and gas deposits, other conditions being favorable, were usually found in anticlinal types of structure. This very undestandable and rational habit of occurrence furnished the first substantial clue to the prospector. Oil occurs in sedimentary rocks, and beds of such rocks are deposited originally in approximately parallel layers. An anticline at the surface, therefore, could be accepted as an indication of an anticline in lower beds. Structural geology became the tool of the prospector, and by its use in the past two decades the majority of the known important oil deposits of the world have been discovered. This is but a partial, and the simplest, statement of the problem, Nine-tenths and more of the important oil pools of the world belong to the great class of accumulations controlled by structural traps—anti-clines, faulted structures, salt domes, etc.—but by no means all of these structures are clearly or adequately expressed at the surface. As the more obvious anticlines were explored and the search for new deposits led to the testing of progressively deeper beds, it became more and more apparent that marked favorable structures involving petroliferous rocks can, and do, exist without any marked surface expression. There are great areas where the surface, covered by some masking material such as water, alluvium, glacial deposits, or sand dunes, affords no clue to structural conditions in the subsurface, and there are also regions where the surface formations are unconformable with the oil-bearing formations. The structure in which the prospector is fundamentally interested is that of the oil-bearing formation itself, together with roof and floor beds. No other geologic information is of interest or importance to him except as it affords clues to the stratigraphy and structure of the supposed oil-bearing formations.

Jan 1, 1932

By Narendrakumar A. Chevli

Exploratory work was conducted in the fabrication of integrated circuitry, specifically linear amplifier circuits, by three general methods: 1) monolithic diffused silicon; 2) a combination of metal thin-film and monolithic diffused silicon; and 3) a hybrid of metal films and diffused silicon on an alunina substrate. In these linear amplifier integrated circuits the followzng conditions were desired: very high-frequency response, high voltage gain, and good thermal tracking stability of electrical characteristics. The resulting circuit designs imposed problems of isolation between elements, layout and smallness of size of active elements, and close tolerances on electrzcal characteristics of the passive elements. Interconnection problems for specific designs resulted from the small dimensions involved and the topography of the hybrid fabrication techniques. The desired integrated-circuit characteristics were achieved with the technologies of categories 2 and 3 above. Solutions to the problems imposed by these characteristics lay in the ability to isolate czrcuit elements of small size while providing a layout designed to minimize element-to-element variations. Sufficient freedom in the formation of passive elements was achieved by uniting the metal film and the monolithic silicon technologies. The most satisfactory designs were based on the beam-lead interconnection and isolation technique. SINCE the advent of integrated circuits, major emphasis has been on fabricating digital integrated circuits. Linear circuits require high performance, high voltage, and tighter tolerance components which are not always compatible with the capability of process technology available for fabrication of these circuits into integrated form. Fortunately the growth of newer and improved processes and materials for fabricating integrated circuits has been an accelerated one. This has now made possible the translation of stringent performance requirements of the linear circuits into microminiature integrated circuits of the same performance. In the exploratory work of fabricating high-performance Linear Integrated Circuits—LIC, the following objectives were formulated: i) fabrication of high-frequency transistors such as the type 2N918 isolated on a single silicon substrate; ii) fabrication of medium-frequency transistors having a very high gain at low collector currents such as the types 2N930/2N2484 isolated on a single substrate ; iii) fabrication of tight-tolerance, high-valued resistors having low temperature coefficients of resistance and stable thermal tracking characteristics, these resistors to be fabricated on an active or passive substrate; iv) simultaneous fabrication of complementary transistors—pn and pnp-on the same silicon substrate; v) fabrication of newer active elements such as MOS, FET transistors along with the conventional active and passive elements on the same silicon substrate. State-of-the-art assessment f all the available processes, materials, and technology to meet above objectives indicated that economic fabrication of LIC cannot be achieved by a single technology for all types of linear circuits. Where design and performance of a given linear circuit can be modified and tolerated to the extent of a particular technology, then alone is it possible to fabricate a LIC using a single process technology such as all diffused, planar technology. In order to evaluate this economic breakpoint with design and performance compromise in fabricating LIC, it is essential that a thorough understanding be obtained of techniques, potentials, and limitations of all the various process technology and materials

Jan 1, 1967

By E. De Goyler

Volcanic origin was among the first of the theories advanced to account for the occurrence of the salt domes of the Gulf coastal plain, northern Louisiana, and eastern Texas, and it is still being re-stated in various forms by the most recent contributors to our knowledge of the geology of such deposits. Argument has been largely by analogy and attention has repeatedly been called to the Mexican oil fields, particularly those of the Tampico-Tuxpam region, because of the occurrence of oil in close proximity to volcanic plugs in those fields, an occurrence supposed to have some resemblance to the common occurrence of oil in the salt domes of the United States. The author, having spent several months of the past year in a general study of salt domes and in a detailed study of certain domes in the United States, and having been acquainted for some time with the exploration of similar domes in the Isthmus of Tehuantepec region, Mexico, and with the general geology of the Tampico-Tuxpam region, Mexico, has reviewed the various theories of volcanic origin for salt domes which have been advanced to the present time. The purpose of this paper is to present such review and to discuss the supposed Mexican analogy. Review of Volcanic Theory R. Thomassyl who had visited the Five Islands of Louisiana between 1857 and 1859, in 1860 described them with some care, noting their distinct character, alignment, and similarity, and ascribing to them a volcanic origin. He regarded them as being akin to the mud lumps in the delta of the Mississippi and was impressed by their symmetry and by the ponds or lakes which occur on several of the islands and which he regarded

Jan 1, 1920

By Dorsey Hager

One of the most interesting fields in North America was discovered, early in 1922, near the towns of Sunburst and Kevin, Toole County, Mont. This field produces oil from the Jurassic beds, which heretofore have been of but little importance as oil producers, and promses to be the

Jan 1, 1923

By Dorsey Hager

One of the most interesting fields in North America was discovered, early in 1922, near the towns of Sunburst and Kevin, Toole County, Mont. This field produces oil from the Jurassic beds, which heretofore have been of but little importance as oil producers, and promses to be the

Jan 1, 1923

By Peter B. Scotland

The mines of the Arizona Copper Co. are situated in the Morenci-Metcalf copper district in southeastern Arizona. This copper-bearing district covers a triangular mountainous area of about 3 square miles, rising abruptly from the gravel plateau of the surrounding country. In this area, an immense intrusion of porphyry lias displaced, shattered, and engulfed the shales, limestones, and quartzites formerly bedded on the basal granite. Outcrops of oxide ore were discovered in 1873, and these surface ores were found to connect in depth with large bodies of high-grade oxide ores in the limestones and shales. The mining of these high-grade ores continued until about 1893, when their rapid exhaustion led to the discovery and exploitation of the low-grade sulphide ores in the adjoining porphyry. Methods of concentration were then devised and the low-grade ores finally rendered profitable. The Arizona Copper Co. and the Detroit Copper Mining Co., operating in the same district, were the pioneers in the successful development of the low-grade "porphyry" properties of to-day. The largest mines of the Arizona Copper Co. are the Humboldt and Clay at Morenci, and the Coronado, Metcalf, and King at Metcalf. These mines produce about 4,000 tons daily of concentrating ore containing from 2.5 to 2.8 per cent. copper. The topography of the country is very rugged and mining operations are conducted principally through adit levels. A few of the mines are opened by shafts, the deepest being 1,100 ft., in the Coronado mine. Ore Occurrence The low-grade sulphide ore occurs as: (1) disseminated deposits in the main stock of quartz porphyry; (2) lode deposits in fault fissures in granite. The high-grade oxide ores were found as tabular deposits in limestone and shale close to contacts with porphyry dikes. Low-grade oxide ore formed the outcrop of some of the sulphide orebodies; the majority of the outcrops, however, were barren.

Jan 1, 1915

By S. F. Shaw

THE Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escalón, Chihuahua; also about 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about. 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along 'the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on, the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season.

Jan 8, 1922

By Henry S. Washington

I. INTRODUCTION. DURING the last twenty years or so the chemical investigation of rocks has made great advances, and it is now generally recognized that a knowledge of the chemical composition is as essential as that of the texture or mineral composition-if not more so-for the proper classification of rocks and study of their origin and relationships. Rock-analyses have vastly increased in number and, what is of greater importance, in quality. New and improved methods permit of greater accuracy than was possible in the early days, and the list of chemical constituents frequently determined has risen from the seven or eight of the greater part of the nineteenth century, to twenty or more. Indeed, rock-analyses with determinations of so many constituents ire now commonly made by the chemists of the United States and Australia, while in Germany, Great Britain, France, and Italy the rarer constituents are determined more frequently-than formerly. As a consequence of this modern, accurate work, it has been discovered that some elements which were formerly supposed to be rare are of wide-spread occurrence and are often present in considerable amount. The fact is further being developed that the elements tend to show certain relations of occurrence or abundance in connection with each other. This is a fact which is applicable to the rarer elements, and which also finds a broad geological and petrological expression in the recognition of petrographic provinces. We are beginning to obtain some definite, though as yet rudimentary, knowledge of the distribution of the elements among igneous rocks. Some of the results along these lines obtained by study of the vast accumulation of analytical data now available are well known to petrologists, while others do not seem to be so gener-

Jan 1, 1913

By Wheeler Davey

WHEN metals are subjected to mechanical working, such as rolling, one of the phenomena that take place is a movement of the crystals of the metal into a system or systems of orientation which bear an angular relation to the direction of working. In rolled metal the crystals may orient themselves with respect to the rolling plane or the rolling direction, or both. Direct evidence of the existence of preferred orientations in rolled metal has been obtained by numerous investigators from X-ray patterns of the rolled metal. Most of these workers used a monochromatic pinhole method. Where the degree of preference for a single orientation is high the monochromatic pinhole pattern may be interpreted by a geometrical calculation based on the angular relationships of the planes in the crystal and the diffraction arcs on the X-ray pattern. This process may be aided by the geometrical construction of the locus sphere (Langenkugel), and reflection circles of Polanyi,1 Polanyi and Weissenberg,2 and Mark and Weissenberg,3 and of the plane polar figures (flachenpolfigur) of Franz Wever.4 R. M. Bozorth5 solves X-ray patterns from metals having a single preferred orientation by means of a series of charts which when placed over the X-ray pattern give directly certain angular relationships, between the crystal planes and the surface of the specimen.

Jan 1, 1929

By Nicholas M. Short

Many a geologist or driller has wished he could somehow climb into a borehole to see for himself what fractures looked like. Or why recovery was poor. Or how the bit was actually lost. Now it is possible to do the next best thing to climbing into the hole. TV cameras are being used for a close-up look at borehole conditions. Ever since television was invented, geologists and others interested in subsurface conditions have wanted a TV camera that could be used in the narrow confines of a borehole. But development of such a camera was slow, mainly because of the need for compact size. Not until the late 1950's did the technology of electronic miniaturization develop to a point where a camera satisfactory for the purpose could be put together.

Jan 1, 1963

By D. D. Porter, C. Fairhurst

Crack propagation in the region of a statically pressurized borehole is investigated to determine a role of the sustained borehole pressure following detonation in a blast. The case of a single-hole bench blast is reduced to a plate model, which is considered both theoretically and experimentally. Based on the principle of least work, it is hypothesized that the path of any crack in the plate will coincide with one of a family of maximum principal stress trajectories. These trajectories were computed, and critical experiments in glass, designed to test the effects of controlled crack origin and of changed trajectories from different loading configurations, confirm this hypothesis. It is concluded that under ideal conditions the crack path can be predicted and that cracks can be produced in the absence of either high-amplitude stresses or stress waves. Energy considerations for crack extension are discussed, and, based on the strain energy distribution, a relationship between hole burdens and spacings is revealed, a critical burden is demonstrated, and a maximum crater width is shown to exist.

Jan 1, 1971

By A. R. Orban, R. B. Engdahl, J. D. Hummell

The initial phase of a research program on smoke abatement from Bessemer converters is described. In work sponsored by the American Iron and Steel Institute, a 300-lb experimental Bessemer converter was assembled to simulate blowing conditions in a commercial vessel. Measurements of smoke and dust were also made in the field on a 30-ton commercial vessel. During normal blows the dust loading from the laboratory converter averaged 0.51 lb per 1000 lb of exhaust gas. This was similar to the exhaust-gas loading of a commercial vessel. The addition of hydrogen to the blast gas of the laboratory converter caused a decided decrease in smoke density. Smoke was also reduced markedly when methane or ammonia was added instead of hydrogen. The research is continuing on a bench-scale investigation of the mechanism of smoke formation in the converter process. DURING the past 2 years, on behalf of the American Iron and Steel Institute, Battelle has been conducting a research program on the control of emissions from pneumatic steelmaking processes. The objective of the research program is to discover a practical method for reducing to an unobjectionable level the emission of smoke and dust from Bessemer converters. PRELIMINARY INVESTIGATION Although conceivably some new collecting technique may be devised which would be economically practicable for cleaning Bessemer gases, no such system based on presently known principles seems feasible because of the extremely large volume of high-temperature gases involved. Hence, the research is being directed toward prevention of smoke formation at the source. A thorough review was first made of former work to determine the present status of the cleaning of converter gases. No published work was found on work done in the United States on collecting smoke or on preventing its formation in the bottom-blown, acid-Bessemer converter. In Europe, however, a number of investigations have been made on the basic-Bessemer converter. Kosmider, Neuhaus, and Kratzenstein1 conducted tests on a 20-ton converter to obtain characteristic data for dust removal and the utilization of waste heat. They concluded that because of the submicron size of the dust, special equipment would be necessary to clean the exhaust gases. Dehne2 conducted a large number of smoke-abatement experiments at Duisburg-Huckingen in a 36-ton Thomas converter discharging into a stack. A number of wet-scrubbing and dry collectors were tried unsuccessfully. A waste-heat boiler and electrostatic collector with necessary gas precleaners was felt to be the best solution for this particular plant. Meldau and Laufhutte3 determined that the particle size was all below 1 µ in the waste gas of a bottom-blown converter. Sel'kin and zadalya4 describe the use of oxygen-water mixtures injected into a molten bath in refining open-hearth steel. They claim that with use of oxygen-water mixtures the amount of dust formed was reduced between 33.3 and 20 pct of its previous level, and emission of brown smoke almost ceased. Pepperhoff and passov5 attempted unsuccessfully to find some correlation between the optical absorption of the smoke, the flame emission, and the composition of the metal in a Thomas converter in order to determine automatically the metallurgical state in the melt. In a recent U. S. Patent (NO. 2,831,762)' issued to two Austrian inventors, Kemmetmuller and Rinesch, the inventors claim a process for treating the exhaust gases from a converter. By their method the inventors claim that the exhaust gases from the converter are cooled immediately after leaving the converter to a degree that oxidation of the metal vapors and metal particles to form Fe2O3 is inhibited in the presence of surplus oxygen. Gledhill, Carnall, and sargent7 report on cleaning the gases from oxygen lancing of pig iron in the ladle. They claim the Pease-Anthony Venturi scrubber removed 99.5 + pct of the smoke, thereby reducing the concentration to 0.1 to 0.2 grain per cu ft, which resulted in a colorless stack gas after the evaporation of water. Fischer and wahlster8 developed a small basic converter and compared the metallurgical behavior of the blow with that of a large converter. Later work by Kosmider, Neuhaus, and Hardt9 on the use of steam for reduction of smoke from an oxygen-enriched converter confirmed that the cooling effect of steam is detrimental to production. From review of all of the published information on the subject, it was concluded that a practical solution to the smoke-elimination problem had not been found. Accordingly, it was deemed desirable to investigate the feasibility of preventing the initial formation of smoke in the converter.

Jan 1, 1961

By Denis G. Maxwell

INTRODUCTION It is my intention in this paper to deal with gold, uranium, diamonds, platinum, manganese, chrome, vanadium and heavy mineral sands. These are the most important strategic minerals produced by the Republic of South Africa which are not covered in other sessions of this program. In each case I have high- lighted the statistics and peculiar advantages which combine to make South Africa a vital source of these minerals. Before proceeding to give individual attention to these minerals I believe it would be useful to define what I mean by 'strategic'. The Concise Oxford Dictionary defines strategic in the context of materials as 'essential for war'. However it is commonly used in a much broader sense than this (often, in fact, very loosely) and I prefer to define it as 'concerned with the acquisition and maintenance of power, whether economic, political or military.' A VITAL SOURCE In dealing with the individual minerals I have quoted statistics which are contained in Tables 1, 2 and 3. Table 1 clearly shows the absolute size of the South African mineral industry. However, it can also be used to demonstrate the importance of the industry to the South African economy if compared with the GNP in 1980 of about R60 billion. Table 4 illustrates clearly how important South Africa is as a supplier of these minerals to most of the important industrialized countries of the Western World. Gold If anyone had any doubts about the inclusion of gold in a list of strategic minerals I am sure that the above definition of 'strategic' will convince them that it certainly belongs there. Similarly no one is likely to have any doubt about the fact that South Africa is a vital source of supply. Tables 2 and 3 show that in 1980 we had 51% of the world's reserves and accounted for 55% of world production. The figures for the Western World are considerably higher. The only other major producer, of course, is Russia, with small but significant production in the Pacific Rim area coming from Australia, Canada, Latin America, Papua New Guinea, Philippines and the U.S. All South African mine gold production is shipped in bullion form containing about 88% gold and 9% silver to the Rand Refinery which is a modern refinery with large scale units capable of refining half a ton of bullion at a time. The Refinery is equipped to produce standard 'good delivery' gold as well as 9999 gold and 999 silver. The Refinery also produces the 22 karat blanks which are, used by the South African Mint to produce Kruger Rands. It goes without saying that the South African gold mining industry leads the world in all aspects of deep-level, narrow-reef mining technology. The industry's metallurgists, too, have a record of tenacious and continuing efforts to improve extraction to the level of the present finely honed efficient process used on all the modern mines. Uranium In 1980 South Africa had 14% of the uranium reserves of the Western World and accounted for 14% of production. In view of the paucity of data I am not in a position to estimate figures for the total world. All the other major sources of uranium in the Western World are situated around the Pacific Rim, with the U.S. and Canada already being major suppliers and accounting for 38% and 17% of Western World production in 1980. Australian production at the time was small but they have very large reserves and production is already rising rapidly. The U.S., Canada and Australia account respectively for 22%, 19% and 29% of the uranium reserves of the Western World. South Africa has been a major producer continuously for 30 years. Nearly all the uranium produced, amounting to about 115 000 tons up to the end of 1981, was a by-product or co-product of gold extraction. During that time the industry has frequently led the world in technological innovation, and has established a reputation as a reliable producer of a consistent, high-grade product. In the latter respect, it is helped by the fact that production is marketed by one company, Nuclear Fuels Corporation, which also blends, dries and calcines the product from the individual mines and samples and assays it before shipping. Diamonds Diamonds are the rock on which the South African mineral industry is founded. The discovery of diamonds in 1866 gave rise to the first major mineral industry in the country and the profits from diamond mining helped to finance the gold mining industry 20 years later. Although now overshadowed by gold, diamonds are still very important in the overall picture of mineral production and exports, as can be seen in Table 1. There are really three separate diamond markets - gem, natural industrial, and synthetic - and, to be meaningful, statistics should be provided separately. Unfortunately separate figures are not available. The figures in Tables 2 and 3 show that, for gem and natural industrial together, South Africa ranks third in the world in production and second in reserves. South Africa is a major producer of synthetics and probably ranks second in the world after the U.S. Recently, of course, Australia was the scene of a major diamond discovery and will soon become the only

Jan 1, 1982

By Charles E. Nelson

THIS paper will outline briefly the practices commonly followed in this country for the melting and refining of magnesium and its alloys. The processes used for the various forms of primary magnesium, as jar as there are differences in the physical shape or behavior, will be discussed. The refining of general fine scrap or secondary magnesium was presented in an earlier paper and will be discussed briefly.1 Inasmuch as the use of fluxes is an essential part of all the melting and refining processes, this paper will deal with these in sufficient detail to point out their unique characteristics, in order to make their use more effective. The outline of this discussion will closely follow that of an earlier paper,2 with such changes and additions as seem necessary to bring it up to date. TYPES OF MELTING PRACTICE All melting and refining processes for magnesium and its alloys require the use of fluxes. These fluxes have a magnesium chloride base and other halide salts or oxides are added to give a density or behavior exactly suited to the particular melting practice. The successful handling of magnesium depends upon the proper use of the correct fluxes. There are four general methods of melting, summarized in the following paragraphs and treated in more detail in the section on Melting and Refining. Open-pot Method The open-pot method makes use of No. 230 flux, which provides protection during melting and a molten pool of flux into which the solid magnesium melts. The flux is stirred through the molten metal bath and agglomerates oxide or similar foreign bodies;, on quiet standing, it separates away, leaving the refined metal ball floating in an encircling layer of molten flux. It forms only a thin fluid film over the surface of the molten metal, which may be parted for hand-ladling processes and tends to cover the metal again after the ladle is removed. A very light dusting of the pot surface with fresh flux immediately after the ladle is removed is desirable. The open-pot method is used generally in the following processes: (I) alloying and remelting in the production of ingot, (2) in sand foundries for premelting and to a smaller extent for the production of small castings, (3) in permanent-mold founding for premelting and also direct ladling to castings, (4) for continuous methods of preparing metal in the production of billets or ingots from which wrought products are fabricated, (5) in general scrap recovery. Crucible Process The crucible process makes use of No. 310 flux, which has the property of being thinly fluid at the start, to provide protection and refining qualities, and then drys out or thickens after a time, leaving a protecting crust on the pot surface until the time of casting. At that time it can be readily skimmed off or held back, thus allowing the contents of the crucible to

Jan 1, 1946

By Frederic P. Dewey

At the Seventh International Congress of Applied Chemistry I presented a paper,' The Assay and Valuation of Gold-Bullion, in which are briefly mentioned a few illustrations of different methods of sampling gold-bullion, particularly cyanide-bars. Since then I have carried on an extensive investigation upon the sampling of gold-bullion in relation to its effects upon the assay-results, in connection with the statement of accounts between the smaller assay-offices of the United States which purchase gold-bullion and the mints where the purchases are re-deposited. Under the name of gold-bullion are included metals of widely different composition. We may have practically pure metal, 999.75 fine or even more in gold; alloys of .gold and silver with only trifling amounts of base metal; alloys of gold and copper with trifling amounts of other metals; ternary alloys of gold, silver, and copper, or gold, silver, and lead; and most complex alloys of from five to eight or more constituents of ordinary occurrence, besides some of the rarer metals occasi'onally. In any one or all of these classes we may have one or more of the metalloids, which may add to our difficulties. Of course, with metal 999.75 fine in gold there is only slight opportunity for different samples to differ in fineness, but on such fine metal we expect the assays to agree very closely, and the sampling must be done with the utmost care. When possible, dip- or granulation-samples of the molten metal should be taken; but when it is necessary to sample bars, the chief point to guard against is surface-dirt.

Jan 1, 1913

COLUMBIA SECTION STANLY A. EASTON, Chairman, FREDERIC KEFFER, Vice-Chairman, L. K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. D. C. LIVINGSTON FRANK A. Ross The first meeting of the Columbia Section was held on March 24, as a part of the 1916 Northwest Mining Convention which was held under the -auspices of the Spokane Mining Men's Club assisted by the Spokane Chamber of Commerce, the technical program being in charge of the Spokane Engineering and Technical Association assisted by the local sections of the A. I. E. E., A. S. C. E., and A. I. M. E. The program of the successive sessions was carefully arranged with view to its application to mining, and in addition to the technical program there were exhibits of ores, minerals, devices, etc., of interest to the delegates, who numbered over 500. A portion of the program was also arranged with special reference to the requirements of the prospector and miner. A reception, a banquet, a complimentary luncheon, a regular daily call' of the Stock Exchange, a visit to the High Schools and to one of the substations of the Washington Water Power Company and to the Union Iron Works kept the visitors entertained, the ladies being looked after by a special committee of ladies who held open house during the entire week. Several important resolutions were passed by the Convention and one by the Columbia Section, A. 1. M. E. With Stanly A. Easton, chairman, presiding, the Columbia Section, American Institute of Mining Engineers, occupied the time between 2.00 and 5.30 p.m., March 24th, the Moorish room of the Spokane hotel being filled with members and their guests. "The Apex Law and the Mineral Surveyor" was a paper presented by F. W. Callaway and generally dis-cussed because of its local application in the Coeur d'Alenes, the conclusions being reached after expensive litigation between two of the large mining operators in that district.

Jan 6, 1916