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By P. CHARTERIS A.

THE following scanty notes on the Roumanian oil-region may serve as an introduction to more detailed future study and description. The Roumauian oil-belt, follows the outer edge of the sweep of the Carpathian Mountains, and may, in a broad sense, be regarded as a prolongation of the Galician belt. It is distributed over a tract of country from 300 to 400 miles in length, with a width of from 15 to 20 miles, and is believed to cover an area of at least 20,000 hectares (59,420 acres). The Government claims that 16,000 to 17,000 hectares of its land is petroliferous. The primary deposits of petroleum are considered to be in the Padeogene (Oligocene) and the Neogene (the salines of the Miocene) formations. Most of the other repositories, especially those of Muntenie, are only secondary, the petroleum there having been introduced by the orogeneric movements which raised the Carpathian Mountains. The oil-field has been divided by the Roumanian survey into two regions, the Flysch and the Sub-Carpathian, as is shown in the accompanying sketch-map, Fig. 1.(p. 518). So far as is yet, known, practically all the seepages and .productive pits and wells are situated oil anticlinals. Those which outcrop in the Flysch region. (called Paleogene anticlinals), as indicated in the sketch-map, Fig. 1, are : Solontz, Middle Oligocene; Moineshti, Moineshti and Tagu-Ocna-beds of the Eocene.

Jul 1, 1906

By C. A. Schempp

STUDY of the adaptability of Tintic Standard ores to concentration dates back to somewhat before January, 1921, when the chloridizing mill at Harold, Utah, was put into operation. The operation of this mill has been fully covered in the TRANSACTIONS (Vol. 73). The process consisted essentially of a chloridizing roast followed by a percolating leach with a nearly saturated solution of common salt, acidified with sulfuric acid; precipitation of silver on sponge copper, and of copper and lead on tin-plate cuttings. This mill was built to treat the low grade siliceous ores having an average content of

Jan 1, 1933

By W. J. O'CONNOR

THE production of lead in the United States for the period from 1720 to 1912 was 10,432,668 tons valued at $924,600,000. The average price during this period was 4.4c. a pound, although lead sold at times below 3 cents. We know that in the early days of lead smelting in Montana lead was deliberately lost in the slag and only enough reduced as bullion to collect the silver. This bullion was freighted by ox team to Corinne, Utah, the terminus of the railroad at that time, and shipped to Swansea or Omaha, Neb., for refining. The slag from some of the above mentioned operations contained as much as 15 per cent lead and has since been resmelted. Since 1921 the production of lead has increased each year and the price and tonnage have been as follows :

Jan 1, 1926

Henry Louis, Newcastle-upon-Tyne, England (communication to the Secretary): I think very highly of the novel and ingenious device of Prof. Richards for analyzing the movement of the various elements of the jig; it is a method that certainly seems to promise valuable results, if we could only make certain that these various indicator-appliances have no effect upon the action of the jig. I would like, however, to suggest that in future experiments the connection between the plunger indicator-rod and the pencil should be made by means of parallel motions, so as better to reproduce the rectilinear motion of the piston. I should expect, if this were done, that the " curve " of the plunger in the Harz jig, at any rate, would be represented either by straight lines or else by quite regular curves, according to the method by which the plunger is set in motion; the apparent combinatioil of straight line and curve seems difficult to explain. With respect to the water-curve, I am afraid I am completely at fault, but no doubt Prof. Richards can explain my difficulty. In Fig. 2, the areas of the screen-side and the plunger-side of the jig are equal. If the piston be a fair fit and the bottom of

Jan 1, 1897

By Louis D. Huntoon

CANADIAN gold production is forging ahead annually and the prospects are that it will continue to do so for many years. Table 1 shows recent annual increases. Production for 1933 will probably reach $70,000,000, and further increases are likely in 1934 and 1935. (Data for November and December, 1932, are estimated throughout this article.) The depression sent many prospectors to the woods so during the last two years many new gold areas have been discovered and are attracting real capital for exploration and development. Several mills came into production in 1932 and mills now under construction will start production in 1933. The offices of mining lawyers are busy. Capital for this new work is obtained from well financed mining companies, syndicates, and individuals who were fortunate enough to invest in the dividend-paying gold mines of the north country in the early days. Prospectors and capital are cooperating. An interest is always retained by the prospector or vender and usually a small amount of real money is given the prospector.

Jan 1, 1933

By Joseph A. Holmes

Iv all new movements unavoidable misapprehensions arise, which should be cleared away, lest they retard the progress of the movement itself. An impression has gone abroad that the movement for conservation of resources is a new movement. No one knows better than the engineer that this is not the case. Men like Douglas and Raymond and John Fritz and Edison and McDonald, and hosts of others, have preached and practiced conservation as applied to mineral resources throughout a long and useful life-time; and, in general, the work of the engineer and the chemist, both in this and in other countries, has been along the line of continually greater efficiency in the use of all available materials. And the results already accomplished through the efforts of these experts are now saving annually many millions of dollars to the people of the United States in materials and labor. It is true, however, that the need for conservation, that is, for a wiser and more efficient use of the natural resources, has taken on a new life, and is being brought home to the people of the United States in a manner which is awakening public interest and even the public conscience. It is, therefore, both appropriate and fortunate that the engineers, the chemists, and the thinking men of all classes are availing themselves of the present impetus to the movement to emphasize anew the lessons which heretofore they have found it more difficult to impress upon the American public or even upon the captains of industry. Still another of these misapprehensions is to the effect that many of the leaders in the present movement hope to bring about conservation of resources through legislation or execu-

May 1, 1909

By S. Arthur Krom

(New York Meeting, February, 1912.) THE James diagonal-plane slimer is specially adapted to handle the finest slimes, but it will also handle sands as coarse as 40-mesh. The saving efficiency of this machine is due to the original construction of the deck, and to the rapid reciprocating movement imparted to it by the head-motion. The deck consists of a plurality of connected planes, having a certain fixed ratio of inclination one to another. These planes intersect each other diagonally to the stroke-line of the table and are arranged so as to give the pulp on the table a double treatment. This double concentration performed by the diagonal-plane deck produces cleaner concentrates and tailings than those obtained by the operation of two separate machines. The action of the diagonal planes settles, combines, and holds all the concentrates in one compact mass, sharply defined from the gangue, and easily cut away without loss. Many slime-concentrating machines distribute the feed-pulp for a distance of 4 or 5 ft. only, and upon a very limited settling-surface. This results in a thick, heavy deposit, from which it is impossible to stratify the values and wash, away the gangue, the resulting products being dirty concentrates, and tailings carrying high values. The diagonal-plane slimer distributes the feed-pulp for a distance of 10 ft., and upon a settling-surface having an area of 40 sq. ft.; in other words, it spreads the pulp thinly on the table, which allows the metallic values to settle through the gangue quickly, forming a bottom stratum from which the thinly-distributed overlying stratum. of gangue is easily brushed away by the feed-water without disturbing the underlying concentrates. Referring to Fig. 1, plane A is the main settling-section, of the table. The feed pulp flows gently down this plane and is

Jun 1, 1912

By W. L. Crentz, E. E. Donath, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom's paper can be written: Q Q = K D'. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0' " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

By E. E. Donath, W. L. Crentz, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom's paper can be written: Q Q = K D'. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0' " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

APPLICATIONS for loan contracts for the exploration, development and mining of strategic and critical metals and minerals are now being accepted by the Department of the Interior. The RFC is authorized and directed by Executive Order 10161 to make such loans but the Secretary of the Interior must pass on the necessity for the loan. Applications should be addressed to James Boyd, acting deputy administrator, Defense Minerals Administration, Department of the Interior, Washington, D.C. rather than to the Field Offices of the Bureau of Mines as was first planned. Application forms are not yet available but it has been learned that data accompanying the application should include the known quantity and grade of reserves, the anticipated rate of production, the equipment, supplies, and man power required for the additional production, etc.

Jan 12, 1950

"No true conception of the Park City mining district can be obtained without first giving consideration to the part it has played as a consistent producer of mineral wealth. Its position in this regard is almost unique in the annals of a lead silver camp. For over fifty years it has been a continuous producer of lead and silver and for twenty years it has added to the world's supply of zinc. Few camps with its productive history are so little known to the mining fraternity for the reason that its life has never been punctuated by periods of ""boom"" which serve to attract general attention, neither has it been the field of operation for promoters who temporarily focus attention upon their scene of action. Its history is one of legitimate mining operations. These were at first carried on by a number of smaller companies. A period of consolidation followed and at the present time the entire production of the camp is in the hands of two major companies and one smaller company. These are flanked by a number of prospecting properties, which are at this time actively engaged in the search for ores and later events will doubtless put some of them in the producing class.A technical discussion of the ore occurrence and mining operations in the camp will be the subject of a paper to be read before this meeting of the Institute. The mission of this article is to supply a ""Baedeker"" where Baedeker is lacking.The town of Park City is a typical, up-to-date, western mining camp which owes its existence as a town of 4,500 inhabitants solely to the mining industry. The camp is located 7,000 feet above sea level, thirty-two miles east of Salt Lake City. It is situated on the Victory Highway seven miles from its junction with the Lincoln Highway and has the benefit of excellent automobile communication with the metropolis of the state. Both the Denver and Rio Grande and the Union Pacific Railroads give daily train service to the camp and effectively solve the transportation problems of the mining companies."

Jan 1, 1925

By C. McCulloch

OPEN-PIT mining of coal is relatively a recent innovation; men still active in the industry can trace its development. Re- viewing the growth of operations from the original horse-drawn scrapers, through the various stages of power equipment to the huge strip- ping shovels of today, one also notes changes in the methods of what the coal man calls preparation at the face. We really should not call it face preparation because, in contrast to underground mining, a face does not exist in strip mining. Further, preparation of the coal for market at the loading point has already, in but a few years, become largely of historic interest only and modern mines as well as old mines recently modernized rely almost entirely on separate and elaborate preparation plants to produce marketable coal. This practice was not voluntarily adopted by the producer but was forced upon him by the inadequacy of previous

Jan 1, 1939

By T. R. Armstrong

Total crude oil production in Mexico in the year 1941 is estimated at approxi- mately 41,000,000 bbl.; a daily average of 112,700 bbl. and a decrease of about 5 per cent as compared with the daily average of 120,000 bbl. produced in the year 1940, and nearly 11 per cent decrease as com-

Jan 1, 1942

By T. R. Armstrong

Total crude oil production in Mexico in the year 1941 is estimated at approxi- mately 41,000,000 bbl.; a daily average of 112,700 bbl. and a decrease of about 5 per cent as compared with the daily average of 120,000 bbl. produced in the year 1940, and nearly 11 per cent decrease as com-

Jan 1, 1942

By Charles L. Elliot

Data on mining applications of geophysical activity in the Free World in 1964 have been made available to SME again this year by the Society of Exploration Geophysicists. Worldwide data were collected as part of an annual service to the mining industry by the Committee for Geophysical Activity of SEG. Data are taken from 245 voluntary responses (53%) to questionnaires circulated to 463 company, government and university organizations engaged in mining geophysical operations and research all over the world. WORLD ACTIVITY Worldwide manpower utilization totalled 9323 professional man-months and $14.5 million was reported spent in mining geophysical activity in 1964. This is up from 9078 man-months and $12.6 million in 1963 and 8065 man-months and $12.8 million in 1962. Worldwide geophysical activity in terms of manpower utilization and expenditures is presented in the accompanying table.

Jan 9, 1965

By F. M. Lewis, J. F. Myers

W. I. Garms-—The authors state that when they added 11 tons of balls to the 45 pct volume ball load, the power needle did not budge. The question arises as to whether any increase in capacity accompanied the 11-ton addition. It is hardly conceivable that all of the balls making up the 11-ton addition were sterile. However, as the work done in the ball mill is not by kilo-watthours per se or balls per se but by kilowatthour-balls, it is possible that the kilowatthourballs in the mill before the 11-ton addition had a different amperage, voltage or robustage than those in the mill after the addition and that the overall outcome was that equal work was done before and after the addition. The authors can keep the efficiency that they got with the 45 pct volume 1-in. ball charge and get additional capacity by putting more kilowatthourballs to work in the form of the addition of 11 tons of 2-in. balls to the present ball charge, and subsequent makeup additions by weight of 20 pct 2-in. balls and 80 pct 1-in. balls. J. F. Myers (authors' reply)-—Mr. Garms points his finger at the 11 tons of "sterile" balls added to the Tri-cone mill. A fact so interesting to us that we felt it should be reported. Clearly, ball slippage at the existing mill speed prevented any further transfer of power from the shell to the ball mass. We agree that the kilowatthourballs would increase, were we charging rough 2-in. balls as suggested by Mr. Garms. The assumption is, of course, that we would get a corresponding increase in work done. Our reported data (CIME meeting, Vancouver, 1946) shows a gain of work accomplished of 7.6 pct as we decreased the ball size from 2 in. to 11/2 in. and a further gain of work accomplished of 2.1 pct when we went from 11/2 in. to 1 in. The small ball results reported by H. R. Banks at Chapman Camp are also very convincing. In the case of 2-in. balls they would take the conventional ball path and start cascading. They would thus destroy the classifying pool over the "foot" of the

Jan 1, 1951

By J. F. Myers, F. M. Lewis

W. I. Garms-—The authors state that when they added 11 tons of balls to the 45 pct volume ball load, the power needle did not budge. The question arises as to whether any increase in capacity accompanied the 11-ton addition. It is hardly conceivable that all of the balls making up the 11-ton addition were sterile. However, as the work done in the ball mill is not by kilo-watthours per se or balls per se but by kilowatthour-balls, it is possible that the kilowatthourballs in the mill before the 11-ton addition had a different amperage, voltage or robustage than those in the mill after the addition and that the overall outcome was that equal work was done before and after the addition. The authors can keep the efficiency that they got with the 45 pct volume 1-in. ball charge and get additional capacity by putting more kilowatthourballs to work in the form of the addition of 11 tons of 2-in. balls to the present ball charge, and subsequent makeup additions by weight of 20 pct 2-in. balls and 80 pct 1-in. balls. J. F. Myers (authors' reply)-—Mr. Garms points his finger at the 11 tons of "sterile" balls added to the Tri-cone mill. A fact so interesting to us that we felt it should be reported. Clearly, ball slippage at the existing mill speed prevented any further transfer of power from the shell to the ball mass. We agree that the kilowatthourballs would increase, were we charging rough 2-in. balls as suggested by Mr. Garms. The assumption is, of course, that we would get a corresponding increase in work done. Our reported data (CIME meeting, Vancouver, 1946) shows a gain of work accomplished of 7.6 pct as we decreased the ball size from 2 in. to 11/2 in. and a further gain of work accomplished of 2.1 pct when we went from 11/2 in. to 1 in. The small ball results reported by H. R. Banks at Chapman Camp are also very convincing. In the case of 2-in. balls they would take the conventional ball path and start cascading. They would thus destroy the classifying pool over the "foot" of the

Jan 1, 1951

By H. R. MacMichael

IN the Chihuahua district of Mexico the first smelting was that inaugurated by the early Spaniards for the production of silver bullion. The ores treated were high in silver and lead. Silver-lead bullion was first produced and the lead then cupelled to waste, with the slag produced running from 5 to 10 per cent in lead and about 25 to 40 per cent silica. The ore was mined by peon labor, often being carried out of the mine on the backs of the men, and then transported by burros. Furnaces were of primitive construction, adobe or rock being used in the earlier period and some iron later when it became available. Blast was originally supplied by bellows manually operated. Such smelting was carried on to a greater or lesser extent until the latter part of the last century, and so extensive was it that many hundred thousand tons of leady slag remained to be treated in modern furnaces. In 1908 a smelter was placed in operation at Chihuahua by the American Smelting & Refining Co. At that time the ore was practically all oxidized and by a little selection, self-fluxing mixtures could be made, but with an average lead content usually under 10 per cent and sometimes as low as 7 per cent. The bullion produced would carry from 150 to 300 oz. silver per ton. The slag made approximated 30 per cent SiO2, 42 per cent FeO, 21 per cent CaO, and perhaps 3 per cent Zn. The ores varied from hard, coarse material which was passed through a crusher, to a considerable quantity of fines which had to be smelted as it came, as crushing the coarse was the only preparation for smelting.

Jan 1, 1933

SUDBURY ore processed by International Nickel Co. of Canada Ltd. was recovered for many years as two mill concentrates, one primarily of copper, and the other mixed pentlandite-pyrrhotite, But, Since iron content of the nickeliferous pyrrhotite concentrate was ten times its nickel value, capacity of smelting was limited by the need for slagging the excess iron. A process for recovering the iron con- tent was developed after some years of research and a $20-million plant was constructed to employ the new method. Built near Copper Cliff, Ont., the plant started operation early in 1956, scheduled for separate treatment of 365,000 tons of pyrrhotite each year. It is only the first unit of an installation which will have a capacity of more than 1 million tons per year of pyrrhotite. By early 1958, production totaled more than 200,000 long tons of 68 pct Fe pellets containing 0.003 pct P, 1.5 pct SiO2, 0.01 pct S, and 0.15 pct Ni.

Jan 8, 1958

By Gerhard Derge

The extension of metallurgical control of steelmaking processes has always made it desirable to have some quick method for determining the oxygen content of molten steel. To meet the practical demands of the steel industry, this method must also be simple enough so that the sampling can be done by the regular furnace crew. This requirement was kept in mind continually in the work to be described. An oxygen value is required for proper control, whether it be of a rimming steel or of a fully killed steel. However, two factors have discouraged the development of such direct methods: i. The reaction C + FeO Fe + CO is rapid enough to make the correct sampling Of the bath a difficult problem. The most generally accepted means of circumventing this difficulty have been the aluminum-killed bomb test of McCutcheon and Rautiol and the aluminum-killed spoon test of Herty.2 The theory of these tests is that all of the oxygen in the iron is converted to Al2O3, which can then be determined by chemical methods. Even when simplified so that the analysis is made by a measurement of turbidity, this method is too slow to be used in routine control. Furthermore, the results obtained have never been entirely satisfactory, and some of the reasons for this will be discussed later in this paper. z. The ordinary chemical methods of analysis for oxygen in steel are not reliable. The only analysis that seems to possess sufficient dependability to be of value is vacuum fusion,3 and the apparatus and technique developed for this have been too complex and slow for routine work. Indirect Methods Indirect methods of estimating the oxygen have been resorted to in mill practice. Generally these depend upon the chemical equilibria involved. The oxygen in the bath is related to other components in the slag or metal that can be analyzed the readily. These methods have many difficulties in common. Steelmaking processes involve a complicated set of interrelated reactions, all of which tend to approach equilibrium at varying rates. The degree to which any particular equilibrium is approached is not well established. Moreover, a proper use of theoretical equilibrium constants requires a more extensive knowledge of the activities of the con- than we now have. This is well illustrated by the irregularities observed when trying to determine the oxygen in the metal by its ratio to the iron oxide in the slag. Equiliblium relations may be used mole readily if they are evaluated by plant experience, but the extent of approach to equilibrium remains an undetermined variable and lack of an entirely satisfactory mean, of determining oxygen for the calibration is felt keenly, For example, the statistical analysis of the relation between carbon and oxygen4.6 illustrates that even iia a single plant wide variations exist under llormal conditions of operation. Never. theless, this is one of the best methods now

Jan 1, 1943