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By J. L. Christie, R. H. Leach

SO much has been written recently about the use of silver to replace scarce metals that certain facts about silver and its uses should be of interest. Figures for the production and use of silver, taken from the Handy & Harman annual reviews of the silver market, are given in Table 1. It will be seen that the rate of production has remained fairly constant and has been affected in recent years by the production of base metals, of which silver is a by-product. In each of the years 1937, 1938, and 1939, the U.S. Government acquisitions alone exceeded the entire world production, the difference, of course, being made up by imports of previously accumulated stocks. In 1940 and 1941 the U. S. Government acquisitions plus the United States and Canadian uses in the arts and industries exceeded the Western Hemisphere production. The U.S. Government pays a premium price for silver newly mined in the United States, at present 71.11c. compared with the price of 35'/8c. for foreign silver, with the result that the current U. S. production is not used commercially for the arts and industries. At the time this is written (June 1942) there is much uncertainty as to the future effect of this situation.

Jan 1, 1942

By Tenney, J. B.

DEVELOPMENT of complex ores in the south- western part of the Rocky Mountain region has been retarded by the prohibitive distance to the nearest suitable zinc treatment plants. In the north- western and central Rocky Mountains the building, cluring tlie past decade, of electrolytic zinc plants at Anaconda, Great Falls, Trail, and Burke has tremendously stimulated the mining and exploiting of such .ores, greatly increasing the production of lead, zinc, copper, gold, and silver. Selective flotation permits the making of high-grade led, copper, and zinc concentrates. If the zinc concentrates could be made free from lead, copper, gold, and silver, they could be shipped economically to Mid- Western retort plants designed for such concentrates. Unfortunately a considerable proportion of the precious metal content accompanies the zinc blende in the ores of this region. Although some of it is saved in 'retort residues, the treatment cost is thereby increased so materially and the proportion saved so small, that .concentrates of ordinary grade cannot stand treatment charges and freight.

Sep 1, 1928

By F. K. Spragins

Growing demand for conventional crude oil in North America in the face of diminishing sup- ply is bringing about increased interest in synthetic fuels. With one commercial plant already in full production, another in the planning and engineering stage and still others being seriously considered, the Athabasca tar sands are proving to be a leading center of interest. Here, and in the closely related deposits, reserves in place total over 700 billion barrels.' When and if fully developed, Athabasca tar sands could make both Canada and the United States substantially independent of all off-shore supplies of crude for many years to come. Its product, a high-quality, low-sulfur synthetic crude, is beginning to enter the market place at a most favorable time. Oil Deposit The main body of Athabasca tar sands, about 250 miles northeast of the city of Edmonton, are centered in an area of something over 12,000 sq mi. The deposit runs as high as 250,000 bbl per acre and the average richness is placed at 100,000 bbl per acre. Of the over 700 billion bbl in place, 400 billion bbl of raw oil are considered recoverable from which 300 billion bbl of upgraded synthetic crude are expected to be produced.' In the deeper zones, thermal stimulation is considered the best approach to recovery, while in the shallow areas several surface mining techniques are deemed practical.

Jan 10, 1972

By F. C. Blake

The best method for the estimation of copper in ores and secondary products is that proposed by Dr. Steinbeck* for the award offered by the Mansfeld'schen Ober-Berg-und Hutten-Direction. It is based upon the decolorization of the blue ammonia solution of copper by potassic cyanide.7 It is necessary for the accurate estimation of copper in arsenides that the arsenic be separated from the copper before the ammonia solution is made. The presence of a notable amount of arsenic renders the titration by potassic cyanide inaccurate, the end reaction being obscured by the appearance of a yellowish-green tint towards the end of the titration. The change of the color of the ammonia solution from blue to the tint caused by the presence of arsenic cannot be used for an end reaction, for the intensity and quick appearance of the latter color depend upon the amount of arsenic present in the solution. In the analysis of speise, the method of separating the copper by an oxidizing and reducing treatment in the muffle, to volatilize the arsenic, gives poor results, and there may easily be some loss of the weighed sample. The separation of the precipitated sulphides of arsenic and copper by treating with sodic sulphide, gives good results, but the process is tedious. I have used the two following methods, which are simpler and more expeditious than those mentioned, with good results

Jan 1, 1881

By W. Luyken, E. Bierbrauer

A number of articles have been published, notably those by R. S. Handy, R. T. Hancock and A. P. Watt in Engineering and Mining Journal, dealing with the calculations involved in ore dressing. These publications demonstrate both the importance of the subject and the lack of success in developing a generally recognized method for comparing enrichment effects. Considering that we may wish to compare enrichment results on similar or dissimilar ores, that we may desire to make the comparison on the basis of either the absolute or the economical efficiency, and that the number of factors upon which the result depends is large, the question arises whether it is possible to set up a positive method for such calculations. In the following pages it is our aim to show that a sure, complete and successful way to overcome existing difficulties has been found. Graphical Analysis of Ore-dressing Processes The following is from Truscott's Text Book of Ore Dressing (London, 1923): x = assay of ore treated (feed). y = assay value of the concentrate. 2 = assay value of the tailing. a = weight of feed. 6 = weight of concentrate. c = weight of tailing. C = fractional concentration = = . a y - z K = ratio of concentration = 1/c a/b = y-z/x-z 2 B = fractional recovery = 9 = C y/x (3) 100R = percentage recovery. Copt. = theoretically best concentration. 100 — Copt = waste in the feed.

Jan 1, 1930

By GEO H. DEIKE

NOT much activity has been evident during the past year in the establishment of co-operative scholarships but the interest among the coal-mining companies is more pronounced than ever. This is apparent from the replies received to a letter sent out by the Committee on the Promotion of Student Interest in Coal Mining to over 120 coalmine operating officials. With that letter was forwarded a bulletin issued by the school of mineral industries of The Pennsylvania State College entitled ?Industrial Scholarships ? a Partnership of Industry and Education.? In that circular was outlined the need for trained men in the war and postwar world, and particularly as such demands pertain to the growth of the mineral industries.

Jan 1, 1943

A. 0. ASHMAN, Palmerton, Pa. (written discussion *).-From a theo¬retical point of view the best method to maintain the cold junction at a constant temperature is by means of a pipe driven in the ground, to which the so-called cold-junction compensating leads are run, ;and of course there are many times and places where it can be successfully used. There are, however, several objections to this method. In the vicinity of any furnace there are apt to be underground flues for preheated air or gases, recuperators, water mains, etc., which will eliminate the probability of a constant temperature. These, of course, can be avoided by carrying the leads to distant locations known to be free, but this is not good practice because the so-called compensating leads have a rather high re¬sistance, which materially affects the accuracy of even the high resistance instruments, unless they are specially calibrated for it. Moreover, the cost of these long leads is almost prohibitive. A better way is to run short lengths of compensating leads to electrically heated constant¬ temperature boxes conveniently located near the furnace in a place that is of fairly uniform temperature. These boxes are on the market and can be procured at a cost that is approximately equal to the cost of 100 ft. of compensating leads. They can be connected to any power or lighting circuit and once set require very little care. One box will ac¬commodate a number of couples.

Jan 12, 1919

By George A. Morrison

The Columbia Chemical Division of the Pittsburgh Plate Glass Co. is at Bar-berton, Ohio, 35 miles south of Cleveland. For many years large tonnages of limestone have been brought to the Barberton plant from distant points. The stone is here burnt in vertical kilns, the resultant product then hydrated and the hydrated lime used in chemical processing. To eliminate the expense of these shipments, the company decided to investigate a limestone bed known to exist on company property at Barberton, where the stone is used. The bed lay at a depth of more than 2000 ft. and was known locally as the "Deep Lime." Chemical analyses of sludge from churn-drill holes made some years ago proved that the limestone was of sufficient purity to warrant diamond-drill exploration. Four diamond-drill holes were put down at well-spaced intervals, to represent fairly an area of four miles by one mile. Cores logged as to chemical and physical conditions were found to compare closely, and to corroborate the earlier evidence that the limestone was of superior quality for chemical use. A plant of 300 tons per hour was subsequently decided upon. SITe The yard at the chemical plant was already so congested that location of the projected mine within its area could not be considered. Eventually a site was selected 2 miles northwest of the plant, near the main line of the Erie Railroad. Here 412 acres were owned outright by the company and stone rights were obtained on 2 50 additional acres. This location required a transportation line of nearly 2 miles (8800 ft.), crossing two major highways, and to avoid interruption of deliveries to the plant, overpasses were planned. Geology The limestone in the immediate vicinity lies about 2200 ft. below the surface. Geologists* identify this stone as Delaware of Devonian age. It is overlain by 18 ft. of unconsolidated (sand and gravel), 100 ft. of water-bearing sandstone, and finally 2080 ft. of shale into which sandstone in thin layers is interbedded. The contact of shale and limestone is abrupt, flat-lying and very pronounced. Berea sandstone, often found at 520 ft., is absent, but Euclid sandstone was encountered, together with a seepage of oil and a small amount of methane gas. The limestone bed itself is 345 ft. thick, and overlies 200 ft. of gypsum. The lower part becomes dolomitic as it approaches the gypsum. A detailed study of the drill cores indicates that the upper 50 ft. are highest in lime and reasonably low in silica. The physical make-up shows several separating cherty layers. These occur at definite horizons and cause distinct partings, which become horizontal planes of

Jan 1, 1946

By EVERETTE DE GOLYER

USE of geophysical methods in the search for new pools and as an aid in the development of known pools and prospects reached a new all-time peak for the oil industry in 1933. The outlook for 1934 is for work to continue at an even greater rate. The area of greatest activity, as in previous years, was in the Gulf coastal plain of Texas and Louisiana, particularly through a belt of territory some 20 to 30 miles wide parallel to the coast line and some 80 miles inland from it-the so-called "Jackson play" or "Conroe trend." This area was surveyed in an attempt to find additional pools of a type similar to Conroe, a pool not discovered directly as a result of geophysical surveys but one which was indicated by refraction surveys before it was drilled and one which was accurately outlined as to structure by reflection surveys shortly after the completion of the first few wells. Surveys were made over this belt, extending from Texas, across Louisiana and into Mississippi and Alabama, chiefly by the reflection method and torsion balance, and to some extent by pendulum and magnetic methods.

Jan 1, 1934

By J. S. Marsh, T. B. Winkler

THE past year, the first full one of peacetime production, proved that the process of beating swords into plowshares has increased in complexity in step with civilization. Further, judging by various remarks of our distaff departments, the crystal balls of certain radio and magazine oracles must have been cloudy, because we have been in formed from time to time that coveted items such as automobiles and refrigerators did not appear in great abundance. This seemingly extraneous matter is really not out of place here, however; the steel producer and the fabricator exist in a sort of symbiosis: the making of consumer goods produces scrap which is returned to the steelmaker who makes more steel, and so on and so forth. Thus, no abundance of automobiles, no abundance of scrap from this normal source; and other sources had been picked pretty clean during the war. To be short, so was scrap. Since the economy of the steel industry lean; as heavily upon iron from scrap as upon iron from ore, the statement on transformation of swords to plowshares follows. But this is not the whole story: after all, ingot production was a record for a peace year!

Jan 1, 1947

By C. Max Bauer

THE most important development in the petroleum industry in Montana, during 1924, was the bringing in of the Hepp well on May 12, by the Midwest Refining Co. This followed three years of active prospecting and drilling in the state by this company. The well is located 35 miles west of Billings, in Stillwater County, and makes a high-grade paraffin oil from the Dakota sand at a. depth of 3825 ft. After flowing for several months at the rate of 150 bbl. per day, the well has been shut in for lack of storage, awaiting further development in the field. TABLE 1. Production Cat Creek and Kevin-Sunburst Fields Month Kevin-Sunburst Pipe- Estimated Cat Creek Pipeline Estimated line Runs Fuel Oil Used Runs Fuel Used January 3,214 0 133,400 140 February 3,250 0 134,248 490 March 11,989 595 163,129 910 April 116,897 1,155 125,918 980 May 179,726 2,310 152,179 770 June 126,131 2,697 122,270 910 July 132,173 2,170 118,034 770 August 202,001 2,695 142,313 1,120 September 187,201 2,135 110,012 350 October 162,589 1,995 121,683 350 November 130,392 2,520 139,900 350 December 107,465 1,780 124,169 0 Total 1,363,028 20,052 1,581,255 .7,140 There are two producing oilfields in the state-the Cat Creek and the Kevin-Sunburst, which produced a total of 2,971,475 bbl. in 1924. The only other field of proved value is Soap Creek, which contains a heavy black oil and is shut in for lack of marketing facilities. Gas is produced for local use at Havre, Chinook, and Baker, and a carbon-black plant is located at Baker.

Jan 3, 1925

By AIME AIME

THE graduating class whom I am particularly addressing are going into the world at least a month earlier than normal, because of the war. You have been free to choose your work. You have chosen to be mining engineers. The principal importance of your engineering education to date has been in teaching you how to think and how through books to have ready access to the accumulated experience of previous generations, as well as the current experience of the day. You should by now have acquired something of the engineering point of view, the open skeptical mind. the power to observe, experiment, and draw conclusions, form theories and test these by further experiment, and weigh the inherent probability of conclusions drawn by others. I am asking you today to consider certain facts and the conclusions I am drawing from those facts.

Jan 1, 1942

By David J. Dunn, Richard G. Martin

Of many physical parameters critical to design of grinding processes, impact of grinding media is among the most difficult to measure or predict. Yet impact of falling grinding balls, pebbles, or rods accomplishes the fine grinding essential to metallurgical recovery of most important minerals. Unfortunately, the same impacts that break ore fragments deform or crack grinding mill liners. A project was undertaken at Climax Molybdenum Company to measure impact forces in operating ball mills so that they might be used to calculate stresses in liner materials and be correlated with service performance of mill liner alloys. Towards that end, a method of measuring impact forces on ball mill liners using an instrumented grinding ball has been developed. Preliminary tests show that impact forces and contact stresses imposed on bare mill liners are quite high but are greatly reduced by cushioning when coarse ore particles are crushed between balls and liners.

Jan 4, 1978

By Harlan N. Barton

A commercially available, portable X-ray spectrograph, lightweight and rugged for vehicle or field camp use, was used to determine Ba, Cu, Fe, Mn, Pb, Rb, Sr, and Zn in stream sediment geochemical samples. Investigations showed a relative standard deviation of 1-3%, detection limits of approximately 100 pg/g and significant matrix effects. Coefficients of correlation greater than 0.9 were obtained between portable X-ray and emission and atomic-absorption spectroscopy analyses. A geochemical map of a known mineralized area showed good agreement with maps prepared by other methods of analysis and sample media.

Jan 1, 1983

By C. G. Dunn

James, Jones, and Leak (JJL) conclude that growth-rate and orientation-distribution data obtained in a steep thermal gradient should be used with caution to account for isothermally produced recrystallization textures. I agree. However, it is not clear whether they conclude a) that the orientation dependence of rate of growth of secondaries in (commercial) silicon iron depends on both temperature and a temperature gradient or b) that, in applying rate data obtained in a steep thermal gradient, the isothermal annealing temperature must be close to the temperature for which the rate data apply. Also, it is not clear what tem-

Jan 1, 1967

By William A. Berg

Vegetation on mine wastes was an important topic at the International Symposium on Ecology and Revegetation of Drastically Disturbed Areas held at Pennsylvania State University August 3-16, 1969. This article summarizes the Symposium papers that dealt with the nutritional and physical aspects of plant establishment on mine wastes. Surface Coal Mining Spoils Germany-In toxic spoil banks created by open-cast coal mining, the material was extremely acid and low in nutrients. It sometimes contained toxic quantities of minor elements and also had a water repellency that resulted in little leaching and high erosion. However, applications of calcareous and hygroscopic ash, fertilization and deep mixing (60 cm) have promoted growth on hundreds of acres. Knobe, N., Rhine Inst. Air Pol., Essen.

Jan 1, 1970

By C. R. Austin

Tan investigation described in this paper deals with the development of high-temperature alloys of the Konel series over a considerable period of time at the Research Laboratories of the Westinghouse Electric and Manufacturing Co. The word "Konel" has been coined to designate a class of alloys which are essentially nickel-cobalt-iron with other elements added, usually in small quantities. Most of these alloys contain titanium, usually about 2.5 per cent. The main consideration related to strength at high temperatures but the thermionic characteristics of the alloys was also of considerable importance. It is, however, with the mechanical properties at elevated temperatures that we are herein concerned. Much attention has also been devoted to their age-hardening characteristics. There is little need to stress the utilitarian aspect of this subject, as it has been discussed frequently. Alloys exhibiting superior properties at normal or elevated temperatures rapidly find many suitable applications. There may be some question, however, as to what constitutes a "superior alloy, " or an alloy that may have good service possibilities at high temperatures. The problem is complex and various means have been employed to predict the useful life that may be expected of a material. In recent years the "creep limit" has been used as the best means of evaluation. Such tests necessarily are prolonged and hence collection of data is very slow. In a general survey of many alloys therefore the creep test is not desirable and recourse must be had to much shorter time tests in order more rapidly to select alloys which appear to show promise. For this reason the present survey has been made using the high-temperature tensile test and a bend test developed by Howard Scott.1 In the tensile test the conditions have been standardized for all tests, so that values obtained are at least comparable, one alloy with another, although the absolute values recorded merely indicate the mechanical properties at the given temperature under a definite rate of loading.

Jan 1, 1931

By J. P. Batcha, J. Robert Denny

Since 1964. Newmont Mining Corp. has been engaged in a systematic research and development of computer techniques for a variety of mine planning applications. The general objective of this effort has been twofold: first, to arrive at a viable near-optimum plan for mining a particular orebody and, second, to decrease the financial investment by reducing the man-hours required for mine planning. Three major phases in the evolution of Newmont's computer techniques for mine planning are discernible. In phase one, the computer's ability to duplicate manual drafting and contour mapping was developed. Obviously, all recognized geologic characteristics had to be included, and consequently the development of computer techniques for the proper incorporation of structure, stratigraphic trends, and other geological features was a significant aspect of phase one.

Jan 1, 1970

By Zay Jeffries

This paper will include a brief discussion of Prof. Howe's paper on The Supposed Reversal of Inheritance of Ferrite Grain Size from that of Austenite.l The general subject of grain refining in steel and iron will also be treated. The conclusions reached are stated in the following hypotheses which are discussed more in detail below. 1. The ferrite grain size in pure iron, the ferrite and pearlite grain size in hypoeutectoid steel, the pearlite grain size in eutectoid steel and the cementite and pearlite grain size of hypereutectoid steel are not inherited from the grain size of the mother austenite. 2. The only structural feature that is generally inherited from the austenite of hypo- and hypereutectoid steels on cooling through their transformation ranges is the position of the excess ferrite or cementite at the austenite grain boundaries, sometimes causing complete and sometimes incomplete networks which outline the old austenite grain boundaries. Rapid cooling through the transformation range will cause the non-inheritance of this structural (network) feature. 3. The austenite grain boundaries themselves are nearly always effaced in all steels and also in pure iron during the At transformations. 4. The grain-size refining of steel and iron is brought about by the combined effect of non-inheritance of the transformation products on either heating or cooling, i.e., the austenite transformation products do cst inherit their grain size from the austenite on cooling through the transformation range nor does austenite inherit its grain size from the products which form austenite on heating. 5. In general, in both iron and carbon steel the larger the austenite grain size, the larger will be the grain size of the transformation products on cooling. This, of course, assumes all other conditions constant except the austenite grain size. An exception is found to this general rule in very pure iron such as electrolytic iron. In this instance small austenite grains may form very large ferrite grains on cooling through Arg.

Jan 1, 1918

By Howard S. Bryant

FROM the viewpoint of the oil producer, the oil refiner, the oil marketer, and the investor, in oil securities, a brief picture of the crude oil supply and demand in the present critical season of the year will be timely and interesting. Although crude oil production has been in a comparatively poor statistical position this year, increased sales and sustained refinery and crude oil prices have allowed increased profits for many oil companies. The large amount of crude oil going into storage during the present period of peak consumption, just previous to the major yearly fall decline in consumption, has caused oil producers to make plans to leave the oil in the ground for the present in several of the areas of large flush production. The present moment is looked on as the turning point in the current year.

Jan 1, 1929