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By William M. Baldwin

Jan 1, 1946

By William M. Baldwin

Jan 1, 1946

By W. A. Stickney, J. W. Town

Tests demonstrated that aqueous solutions of sodiu~n sulfide would dissolve over 95 pct of the cinnabal- in 5 pct Hg flrotation concentrates and 60 to 90 pct of the cinnabav in low-grade ol-es. Double-leach tests showed that potassiutn sulfide would dissolve 90 pct of the avsenic sulfide in Hg-As satnples and only 1 to 10 pct of the Hg; the sodium sulfide would then dissolve 80 to 90 pct of the rernaining Hg and 30 to 70 pct of the vemaining As. 1 HIS paper describes the extraction, by alkaline sulfide solutions, of mercury from cinnabar-bear ing ores and flotation concentrates. Leaching time and solution temperature had minor effects on mercury extraction when compared to the effects of reagent quantity and ore type and grade. Cinnabar, although readily soluble in sodium sulfide, was only partially soluble in potassium sulfide and essentially insoluble in ammonium sulfide. A double leach process was developed to extract selectively the arsenic from Hg-As products with K2S and to treat the residue with sodium sulfide-hydroxide solutions to extract the mercury.' Mercury was then recovered from the pregnant solutions either by precipitation with metallic aluminum or by electrodeposition. The solubility of HgS in alkaline sulfide solutions was first reported by Volhard in 1878.' The first reported commercial application was made in 1915 when Thornhill applied the method to the treatment of an amalgamation tailing.3 Mullhollen, in 1911. described the chemical reaction of HgS with Na,S and alkaline hydrate to be:4 Most investigators have reported using a 4-pct sodium sulfide and a 1-pct sodium hydroxide soluti~n.3-4 An increase in temperature or excessive dilution of the solution causes the reaction to be reversed. Church Holmes described a similar process used for the extraction of antimony from silver concentrates at the Sunshine Mining Company's mill at Kellogg. Idaho.5 More recently. Erspamer and Wells reported the results of leaching studies on a Hg-Sb ore from Alaska.6 EXPERIMENTAL PROCEDURE Leaching tests were made on samples of mercury ore from eight deposits in Oregon, Washington, and Idaho. In addition. tests were made on flotation concentrates from seven of the samples as well as a flotation concentrate from an operating mill. Since previous investigators reported reagent requirements greatly in excess of that required by the equation HgS + Na2S = HgS . Na2S, initial studies were made on chemically pure HgS. Results showed that the reaction actually required about 1 g of Na,S per g of HgS in an aqueous solution rather than 0.338 g of Na,S as indicated by the equation. To check further the matter of reagent requirements, Na2S and HgS were mixed together in equal mole ratios. Water was then added, a drop at a time, until the components reacted; X-ray diffraction analyses showed no HgS nor Na,S present. The yellow hydrate compound which formed would not redissolve until about three additional mole equivalents of Na,S were added to the solution. This indicated that a stable solution would require at least 4 moles of Na2S for each mole of HgS. While these implications may be valid for pure HgS, the possibility of entirely different results caused by the existence of other elements present in ores and concentrates was recognized. Consequently, experiments of the same order were made on samples of a flotation concentrate from a producing mill. The concentrate, containing about 18 pct

Jan 1, 1962

By Edward V. D’Invilliers

In connection with some recent professional work in the coalfields of Western Pennsylvania, with special reference to results of coking operations, I was asked to compile a statement giving the estimated cost of mining coal and manufacturing coke at two hypothetical plants of 500 ovens each, giving the relative yield of coal in coke at each plant; and, upon the average number of working days in each of the past five years, from 1899 to 1903, together with average selling price of coke at the ovens, to prepare an estimate of the relative commercial returns in each district. What seemed at first sight to be a comparatively simple proposition, involving only the ordinary elements of mining and coking costs, became complicated by the lack of standard published records of mining costs and sales, which would be applicable to the subject at issue. Upon searching through the usual channels of Government publicatious and the files of our technical societies and mining periodicals, I was surprised to note the absence of fundamental factors that would approximately meet the case in point. The very elaborate and interesting statistics annually published by the National Government' do not supply the required data for the following reasons:—1. Being reported by arbitrary districts, the average values are too general to be applied to special fields. 2. The value of coal charged to the ovens is apparently based upon the regional average value of the coal if sold in the market, and not upon the cost of production. 3. Some plants only use the slack (a by-

Jan 1, 1905

By E. E. Bach

STATEMENT OF THE PROBLEM THE administration of industrial organization today embraces more than the cost of production and selling prices. Competition is deeper seated than mechanical devices, overhead charges, and a shrewd manipulation of the markets. Despite the "down-to-the-minute" equipment and the "last word in organization," it is quite evident that "capacity production" will be an unknown quantity until the workman is considered as a producer, in relation to his home, as he is now considered in relation to industry. Whether or not a man shall do an honest day's work is as much a psychological condition as it is a matter of physical strength or skill. His attitude toward his work each morning is determined, to a large degree, by the environment of his home. Whether this attitude, good or bad, obtains the day through will depend entirely upon the one fact as to whether the corporation which employs him does or does not differentiate between the mechanical factor and the human factor in industry. To be more specific, sociological work, under whatever name, should be of such a character as to influence the life of a workman in such a manner as to establish a cooperative interest in his work, foster within him a spirit of contentment in his home, lead him-so to employ his leisure time that he will not lower his efficiency as a workman, destroy his domestic happiness, or endanger his standing in the community as a citizen. While no fixed rules of procedure can well be formulated for the development of the work, yet definite lines of activities will readily present themselves as applicable to the individual needs of a community. This is especially true where community influences and agencies pertaining to general welfare are easily correlated.

Jan 2, 1918

By Franklin H. Sharp, Kenneth L. Clifford

During the last few years the New Lead Belt of Southeastern Missouri has become the main source of lead in the United States. It also produces significant amounts of zinc, copper and silver. The mines are located on a narrow, mineralized trend extending southward from Viburnum, MG. for about 35 miles. The ore occurs as replacement deposits in the Bonneterre lime- stone formation which is about 1000 ft below the surface. In most of the mines, enough water is produced to supply the milling requirements without any reuse. There are dry areas, however, and at least two mills must rely on water reclaimed from their tailings lake to augment the mine water. These mills have no choice but to utilize recycled mill water.

Jan 7, 1973

By David B. Reger

The year 1935 was mostly quiet in West Virginia, and devoted to routine drilling in old pools and extensions. A notable exception to this general rule, however, was the further development and proving of a field of gas discovered in 1930 in the deep Oriskany sand (L. Dev.) in Kanawha County, as later discussed. No new pools of oil were found and little or no attempt was made to search for them. No new pools of gas were recorded but various extensions of old pools were made. There were no new pipe line extensions of consequence, either for oil or gas. Operating technology was much the same as in recent years, there having been some further advances in repressuring oil wells and in the use of acid for treating small wells in calcareous formations, and some change in the technique of shooting gas wells. Financially, there has been a full market for all crude oil produced and a fair market for gas. There have been occasional transfers of producing oil or gas properties, mainly between established companies. Most of the attempts made to finance mergers and new developments have failed largely because of difficulties encountered under the Federal securities act. This situation has prevented the normal turnover of properties by small operators who frequently desire to sell partly developed interests and then step out into new ventures. New Development In 1935 the State issued 569 permits for drilling and records the same number of completions. One trade journal records 533 completions and another 483. A running record kept by the writer accounts for 713 completions, with 156 oil wells, 417 gas wells and 140 dry holes (Table 3). Some of these completions may be old wells drilled to deeper sands. Some, apparently, have been drilled without legal permit. Extensions of Producing Areas Ritchie County has again led all others in new drilling, with 137 completions as compared to 74 in Calhoun and 61 in Cabell. This Ritchie County drilling was done mainly to extend or further develop old pools

Jan 1, 1936

By David B. Reger

The year 1935 was mostly quiet in West Virginia, and devoted to routine drilling in old pools and extensions. A notable exception to this general rule, however, was the further development and proving of a field of gas discovered in 1930 in the deep Oriskany sand (L. Dev.) in Kanawha County, as later discussed. No new pools of oil were found and little or no attempt was made to search for them. No new pools of gas were recorded but various extensions of old pools were made. There were no new pipe line extensions of consequence, either for oil or gas. Operating technology was much the same as in recent years, there having been some further advances in repressuring oil wells and in the use of acid for treating small wells in calcareous formations, and some change in the technique of shooting gas wells. Financially, there has been a full market for all crude oil produced and a fair market for gas. There have been occasional transfers of producing oil or gas properties, mainly between established companies. Most of the attempts made to finance mergers and new developments have failed largely because of difficulties encountered under the Federal securities act. This situation has prevented the normal turnover of properties by small operators who frequently desire to sell partly developed interests and then step out into new ventures. New Development In 1935 the State issued 569 permits for drilling and records the same number of completions. One trade journal records 533 completions and another 483. A running record kept by the writer accounts for 713 completions, with 156 oil wells, 417 gas wells and 140 dry holes (Table 3). Some of these completions may be old wells drilled to deeper sands. Some, apparently, have been drilled without legal permit. Extensions of Producing Areas Ritchie County has again led all others in new drilling, with 137 completions as compared to 74 in Calhoun and 61 in Cabell. This Ritchie County drilling was done mainly to extend or further develop old pools

Jan 1, 1936

Aamot, Olav Crone, (M'29) Chem. Engr., Elektrokemisk, Raadhusgt. 23, Oslo, Norway. Abadilla, Quirico A., (M'3S) Min. Engr., Dir., Bu¬ reau of Mines. Manila, P. I. Abbott, Agatin Townsend, (J'40) Jr. Engr., Phelps Dodge Corp., Morenci Branch, Morenci. Ariz. Abbott, Clarence E., (M'04) Civil Engr., V.P., Ten¬nessee Coal Iron & R.R.. Co., 1542 Brown -Marx Bldg.. Birmingham, Ala. Abel, Raymond L., (M'28) Chem. Engr., Command¬ing, Officer, Pittsburgh Chem. Warfare Procurement Dist., American Bank Bldg., Pittsburgh. Pa. Abel, Walter D., (M'32) Alin. Engr.. Div. of Cor¬porations, State of Calif., 403 California State Bldg., Los Angeles, Calif. Abele, Louis T., (M'31) 423 3rd Ave., Decatur, Ga. Abell, Leo M., (M'31) Mill Supt. & Met., Emperor Gold Min. Co., Led., Vatnkoula, Fiji Islands. Abernathy, G. E., (M'38) Geol., Kansas State Geol. Survey, Pittsburg, Bans. Abernathy, Jack H., (M'40) Peer. Engr., c/o Superior Oil Corp., National Bank of Tulsa Bldg., Tulsa, Okla. Aborn, Robert H., (M'10) Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. Abraham, A. W., (M'39) Peer. Engr., Richfield Oil Corp., 555 S. Flower St., Los Angeles, Calif. Abramowitz, William L., (J'40) Chem., Industrial Inventions, Inc., 103 Foster Se., Peabody, Mass.

Jan 1, 1942

By W. M. Clark

OUR interest in the matter of pyrometers and pyrometry is primarily that of a user of considerable quantities of heat-measuring equipment; and while we play be somewhat critical on the subject we have aimed to make the nature of these comments constructive. The glass industry in America dates back to 1609, when Capt. John Smith started a small glass plant near Jamestown, Va., with a few Italian workmen, to manufacture glass beads for trading with the Indians. While the industry has expanded until it has reached a volume of over $200,000,000 per annum, the means of heat determination in Colonial days was the human eye, and in much of the industry the same means is used today. About 15 yr. ago the largest glass-house supply dealers began to sell platinum pyrometers, but as nearly all of these proved un-satisfactory, pyrometers met a temporary rebuff from the old-time glass manufacturers. As their ruggedness of construction, reliability, and stability have been improved, however, pyrometers have gradually won their way into more and more extensive use throughout the glass trade. But there are still many applications where pyrometers are not used, largely because of cost and upkeep considerations. There are two distinct fields in glass works for pyrometry. The first calls for accurate temperature measurement and the second only demands knowledge of relative comparative fluctuations of temperature, to know whether the work is becoming hotter or colder. For example, in a lehr for annealing glassware and removing strain we want accurate temperatures to know that the ware is heated to the critical temperature for rapid removal of strain. On the other hand, in a glass pot furnace nearly 120 ft. (36 m.) in circumference, where the pyrometer couples only project inside the furnace wall for less than 2 in. (50 mm.), it is inconceivable that these few inches represent the accurate temperature at every point of the 120-ft. circumference but the relative readings as to whether the pyrometer shows schedule temperature fluctuations are valuable indications for control. The glass melting in the pots is,

Jan 8, 1919

By Charles Schwab

WHEN I leave this life, as an employer of labor there is no one thing that I want so much to be engraven upon my monument as the fact that I have been one of the men who have worked, whether with my brains or my hands, for the advance-ment of industry in the United States, and to be regarded, as I should like to be regarded by labor with love and kindly remembrance for our years of association. In my relationship with my employees, I have always contended that every man should be paid for what he does. I will not employ or be associated with any kind of labor of which the organization insists that a man shall receive a fixed sum of money for his day's wages, however poor or good his day's labor may be. What applies to the common laborer applies equally well to the management, the brains of an industrial establishment. I have always thought of industry as a three-legged stool, with capital, management and labor as the legs. All three legs of that stool must be there before that stool can stand up. If you take any one of those legs away, it is going to topple over. The. three must stand together for successful business accomplishment. I believe that a man who has his labor to sell, to put it plainly, has just as good a right to bargain for the best price for that labor as those who employ him. It is a perfect right for him to do so. If the government of our United States is right, our method of handling labor in our Bethlehem plants is right because it is representative and democratic. We have our labor elect delegates; elect representa-tives from their own ranks, who shall meet frequently. That constitutes, as. it were, the House of our great Congress in Washington, the industrial house. We have our management, who represent the Senate, who meet independently. Working men have learned to express their views freely as to whether they are treated fairly and whether conditions are right or wrong.

Jan 12, 1922

By Rush Greenslade

The oil and gas lease is the basic contract of the oil and gas industry; it is the foundation stone upon which the producing industry, particularly, is based. As the industry is precarious and highly speculative, the foundation contract should be of the utmost integrity and certainty. But right there an anomaly exists; the oil and gas lease is the most obscure, most uncertain, doubtful contract in the realm of law today. That is a condition that must be considered when taking oil and gas leases, and when buying, selling, and holding them. It may fairly be asked why should this industry rest upon so insecure a foundation. Why should not the oil industry rest upon the contract that is the basis of all industry, the warranty deed? There are many contributing reasons, but the principal one is business expediency. The Anglo-Saxon idea of ownership of land is that every land owner owns from the center of the earth to the sky—all that is above and all that is below—consequently the oil and gas are owned by the person who owns the surface. That idea is not exactly true with reference to oil and gas, for many states have adopted the doctrine that oil and gas are like wild animals; they are fugacious and migratory and belong to the man that traps them. But, except for that doctrine, we believe that oil and gas are owned by the owner of the surface, wherein we differ from the Latin-American countries where the mineral rights are owned by the government. The United States was settled largely by homesteading. The owners of land were, in the main, farmers, who did not have the means or the faith to drill for oil or gas. The operators or speculators did not want to buy the land on the mere possibility of finding oil; hence a compromise resulted by which the land owner gave the speculator or the operator what he called an oil and gas lease, or a right to go upon his land and drill for oil and gas. What is supposed to be the first oil lease placed on record reads as follows: Agreed this 4th day of July, a.d. 1853, with J. D. Angier of Cherrytree township in the county of Venango Pennsylvania that he shall repair up and keep in order the old oil springs on land in said Cherrytree township, or dig and make new springs, and the expense to be deducted out of the proceeds of the oil, and the balance, if any, to be

Jan 1, 1924

By W. H. Fulweiler

The writer would define the term "Use Classification" as a discussion of the qualities that coal should possess to fulfill the requirements of the industry or process in which it is to be used. The general problem of the gas industry is to transform the maximum amount of the thermal energy in coal into a gas of specified quality. The qualifications that a coal should possess to be useful in the gas industry are complicated by probably a greater number of factors than in most industries. The most important of these is the delivered price of the coal. While the- general problem of the industry is as given above, yet the actual problem is the production of gas of a specified quality at the minimum cost. The relative cost of coal and the selling prices for the residuals which are influenced to a large extent by geographical locations are of determining importance as effecting the cost of the gas. It is unfortunate that we cannot disassociate cost figures from a discussion of the desirable characteristics and this results frequently in the use of coal in one location that will be looked upon as quite impossible in another location more favorably situated. Without going into any discussion of the freight rate problem we might merely point out that in general the freight on the coal is equal to or greater than the mine price. It must be evident, therefore, that price must always be considered in any discussion of the effect of the characteristics of a given coal. Two Classes of PRocesses In discussing the characteristics of coals for use in the industry, we must divide the processes in use into two classes: (1) where the coal is destructively distilled at high temperatures resulting in the formation of coke in the liberation of gas and by-products, and (2) where the coal is consumed by combustion in air or steam with a production of gas and by-products leaving only clinker as a residue. The Germans differentiate these two types of processes in their words"' entgasung'" and'" vergasung."' In the distillation processes, we have the effect of the coal on the yield of gas and its quality; the quantity and quality of coke; and the

Jan 1, 1930

By C. E. Lesher

THE Disco* process for the production of low temperature coke and its immediate predecessor, the Wisner or Carbocite process have been described in the voluminous literature of low temperature carbonization.1 This paper will describe the development of the process from the first attempt at commercial operation by the American Gas and Electric Co. at Philo, Ohio, Yn the 1920's to the successful operation in 1949 by the Disco Co., a division of the Pittsburgh Consolidation Coal Co., of the 1000-ton per day Disco plant near Pittsburgh, see Figs. 1-2. In the 1924 coal industry depression following the hectic post World War I expansion, the northern Appalachian, unionized bituminous coal fields were affected first and foremost, and Western Pennsylvania as hard as any. Competitive market pressure was heaviest on the lower grades of steam coals, notably the from the Panhandle district where ash and sulphur are inherently higher than in the same Pittsburgh coal bed to the east along the rivers. The firm structure of Panhandle coal while favoring the prepared sizes, depressed the usefulness and value of the finer sizes. Panhandle slack and nut slack were marketed with difficulty at consistent, and at times considerable, loss. Many solutions were suggested, and the Pittsburgh Coal Co. investigated all. Lower delivered prices through lower mine costs and more advantageous freight rates were obvious goals, but equally obvious were the difficulties of self attainment of either in any substantial measure. Selling Btu's in pipes was abandoned as an idea after a thorough study of the economics of distribution of what was then, and is even now, the only developed continuous process of complete gasification of bituminous coal-producer gas. Although the coal company purchased huge blocks of electric power, it sold not a car of coal to the central power stations. Public utilities controlled the markets for electric current, and it was found that no matter at how low a cost current might be put on the bus bars by the coal company, distribution to its widely scattered coal mines made such an enterprise practically impossible. Consolidation of underground operations and a huge modernization program of mining operations in the 1920's were but preparation for the introduction of mechanical cleaning of the coal for market, particularly the smaller sizes of steam, gas, and by-

Jan 1, 1953

By C. E. Lesher

THE Disco* process for the production of low temperature coke and its immediate predecessor, the Wisner or Carbocite process have been described in the voluminous literature of low temperature carbonization.1 This paper will describe the development of the process from the first attempt at commercial operation by the American Gas and Electric Co. at Philo, Ohio, Yn the 1920's to the successful operation in 1949 by the Disco Co., a division of the Pittsburgh Consolidation Coal Co., of the 1000-ton per day Disco plant near Pittsburgh, see Figs. 1-2. In the 1924 coal industry depression following the hectic post World War I expansion, the northern Appalachian, unionized bituminous coal fields were affected first and foremost, and Western Pennsylvania as hard as any. Competitive market pressure was heaviest on the lower grades of steam coals, notably the from the Panhandle district where ash and sulphur are inherently higher than in the same Pittsburgh coal bed to the east along the rivers. The firm structure of Panhandle coal while favoring the prepared sizes, depressed the usefulness and value of the finer sizes. Panhandle slack and nut slack were marketed with difficulty at consistent, and at times considerable, loss. Many solutions were suggested, and the Pittsburgh Coal Co. investigated all. Lower delivered prices through lower mine costs and more advantageous freight rates were obvious goals, but equally obvious were the difficulties of self attainment of either in any substantial measure. Selling Btu's in pipes was abandoned as an idea after a thorough study of the economics of distribution of what was then, and is even now, the only developed continuous process of complete gasification of bituminous coal-producer gas. Although the coal company purchased huge blocks of electric power, it sold not a car of coal to the central power stations. Public utilities controlled the markets for electric current, and it was found that no matter at how low a cost current might be put on the bus bars by the coal company, distribution to its widely scattered coal mines made such an enterprise practically impossible. Consolidation of underground operations and a huge modernization program of mining operations in the 1920's were but preparation for the introduction of mechanical cleaning of the coal for market, particularly the smaller sizes of steam, gas, and by-

Jan 1, 1953

By Robert B. Fulton

It is a pleasure to talk to you about the world economics of industrial minerals on this occasion of AIME's 100th anniversary. In order to fit this topic into the time and tenor of such a session as this where you are hearing subjects equally broad in scope one after the other, I will deal with the subject through the medium of eight minerals selected to illustrate import- ant economic factors. I must admit to some bias in the selection, since I picked personally familiar ones to elucidate facts of life in the industrial minerals business. It is a very interesting field, different in many respects from metals and certainly far different from petroleum. The minerals chosen are celestite, diamond, fluorspar, salt, sulfur, ilmenite, rutile and zircon. Celestite The market for celestite is mainly in the U. S. where it is consumed in the manufacture of strontium compounds for red-colored flares and other pyrotechnics, for the production of electrolytic zinc, for glass manufacture, and for the manufacture of ceramic ferrites. Smaller markets exist in Europe and Japan. Production comes from England, Mexico and Spain, and a new mining operation is being started in Nova Scotia. There is no significant production in the U. S. nor in the other principal consuming countries, except England; so it is mainly an international commodity. Celestite illustrates many of the factors important in the economics of industrial minerals. To have a marketable product, grade and freedom from deleterious elements are important for materials used by the chemical industry. In the celestite used to make strontium nitrate, calcium is the most objectionable of the commonly associated cations. Selling price is adversely affected because nitrate manufacturing costs are greatly increased if calcium is pre sent, hence less can be paid for the raw material. Meeting specifications can add significantly to the vendor's cost; hence a balance must be struck between the producer's capability and the consumer's requirements, permitting a reasonable profit for both. Sizing of industrial mineral products is often important to the consum-

Jan 1, 1971

By John V. Beall

Copper production in the. United States in 1972 amounted to 1,658,000 tons according to the USBM. This figure is up over 1971 but falls below 1970 production of 1,719,101 tons. This report is essentially about the status of copper mining operations in the U.S. and is an update and expansion of the report "Southwest Copper-A Position Survey" published in [A=], October 1965. At that time, the trend was toward using larger equipment to mine lower grade ore and toward the expansion of dump leaching practice. That trend continues today but, it is overlain by intensive activity to comply with existing environ¬mental legislation and uncertainty over proposed revisions of venerable laws governing mining. In the U.S. today there is, practically speaking, no excess smelting capacity so that expansion of copper production through the startup of new mines is inhibited. Owners of a large undeveloped orebody would have to decide before going into production whether to sell the concentrates offshore, which has many problems, whether to try one of several unproved chemical processes for producing refined metal from concentrates or embarking on the construction of a traditional pyrometallurgical plant in the face of considerable uncertainty over the pollution standards that eventually must be met. The situation is such that not only is the present rate of U.S. copper production threatened but the ability to meet projected increased demand in the years ahead may have been severely retarded.

Jan 4, 1973

By E. Topanelian

In recent years considerable progress has been made in the development and application of mathematical techniques for the solution of certain problems involving economic "strategies". Such a problem might involve, for example, the scheduling of shipments of a commodity from a number of sources to a number of destinations. The object would be to schedule the shipments in a manner so as to satisfy the destination requirements and at the same time minimize the transportation costs. The solution to such a problem is not necessarily intuitively obvious. The "obvious" solution is frequently far from optimum. If the shipments are to be made from, for example, only two sources to four destinations, the optimum schedule is readily found. However, if shipments are to be made from, say, 10 sources to several hundred destinations, even a competent and experienced scheduler may spend considerable time in finding a reasonable answer. Even then he is not sure that he has the optimum solution. Furthermore, he has no way of knowing how far from optimum the answer is. Consequently, he does not know whether he should accept this solution or seek a better one. Prior to the advent of large high-speed digital computers, little more could be done with such problems because of their great size and multiplicity of possible solutions. A problem involving 20 sources and 50 destinations would require choosing, from a very large number of possible combinations, the optimum combination of 1,000 variables. The best one could do was to utilize intuition, extrapolation from past experience, and other non-exact approaches. With a high-speed computer, however, such problems can be solved providing a reasonable computational procedure (or algorithm) can be utilized. The purpose of this paper is to describe such a procedure (linear programming) and to apply this procedure to a production scheduling problem. THE RESERVOIR PROBLEM A simple reservoir model is used throughout this analysis to illustrate the use of linear programming. Even the simplest reservoir behavior problem is nonlinear in both space and time, but if the geometry is fixed for a particular study and the time variable is quantized, the resultant system may be described by linear constraints on the variable production rates. Crude oil is available from five separate sources and is delivered to a pipeline. Sources 1, 2, 3 and 4 are ideal reservoirs and therefore are subjected to reservoir flow restrictions. Source 5 is labeled "Outside Source" and crude oil from this source is assumed to be available in unlimited quantities without considering reservoir conditions. The general problem is to determine the schedule of crude oil production from five sources which, over an eight-year period and subject to certain restrictions, will result in maximum profit. "Profit" is defined to encompass all economic factors and expenses involved in producing and selling crude oil to a pipeline facility. Such economic factors are lumped to the extent that the term represents the dollars profit from one barrel of crude oil from any of the five sources entering the pipeline system. Table 1 presents the assumed profit per barrel for oil from any of the five sources over each of the four time periods. In this chart the eight years is broken into four equal intervals of two years. The selection of four time periods of two years each and the values representing the potential profit are completely arbitrary selections for the purpose of illustrating this idealized reservoir problem. In any practical application of this work a careful economic study would have to be made in order to estimate potential unit profits for time periods as far in the future as eight years. In this particular study it is assumed that all of the potential unit profits (C) are known and fixed before the production schedule is attempted. For each reservoir arbitrary values are assigned for

By Raymond B. Ladoo

TIIe milling of talc, as is the case with many non-metallic minerals, until recently, has not received adequate technical consideration, for the talc industry has become of importance only within the last decade. At first, talc was used only in the massive form, for foot warmers, griddles, and so on, and milling methods were unnecessary. As the demand for ground talc increased, producers adopted the machinery used in the milling of flour; in fact, many talc mills were rebuilt flour mills. Improvement has been slow, but today several types of grinding and separating machinery are in use; many of them, however, are still inadequate and inefficient. To determine the best methods of milling talc, it is necessary to understand the essential properties a talc must possess to fit it for a particular use. For toilet purposes, whiteness, freedom from lime and grit, fineness of grain, and good "slip" are essential. As a paper filler or coating, the talc must be white, uniform, and fine grained, have a good slip, and be free from grit and iron; freedom from lime is a disputed point. Fibrous talc is supposed to be superior to massive on account of the interlocking of grains in the paper, thus increasing its strength; this point, though, is in doubt. In general, talc for the paper industry need not be of as high quality or as fine grained as that used for toilet purposes. Talc is usually bought by sample, for which reason it is difficult to state the essential properties for use in paint, rubber, roofing, and so on. The adoption of standard screen tests and standard grades by producers is necessary before an accurate basis for manufacturing or selling standards can be established. Off-color talcs might be utilized, as in Germany and Austria, by the establishment of standard grades of colored talcs. The machinery to be used depends on whether the talc is fibrous, foliated, or massive; hard or soft; of uniform or variable grade; pure or impure. In some cases, it is possible to change the mining practice or to utilize different sections of the deposit in order to vary some of these factors, but in many cases these factors are fixed, so the milling must be designed to suit the conditions.

Jan 1, 1922

By Frank Peterson

THE manufacture of gasoline by extraction or precipitation from the natural gases in which it is found, the present status of. the industry, its past development and future extensions; offer a subject which is so broad that to handle it in its entirety would require a voluminous paper. The writer will, therefore, attempt to concentrate the essential matter of the subject for a general presentation, giving some of the most interesting details of the factors that are important to the industry. This industry has drawn liberally on the principles of physics and chemistry, and, to a large extent, has had to adapt such information as is most useful-not from data recorded with reference to petroleum, but from data recorded with reference to general treatment of other materials. Because of the complex character of the petroleum series of hydro-carbons and the fact that data, such as solubilities, vapor pressures, etc., of the different petroleum compounds have not been determined, we are still working by rule of thumb in. some essential phases of the industry. Furthermore, the difficulties of determining such data are almost insurmountable. We have not one,, but two butanes to deal with-not one, but several, pentanes, hexanes, heptanes, and, as we ascend in the series the complexity and multiplication of isomers increases at such a rate as to make the task of isolating and studying their physical characteristics almost beyond the hope of possible attainment. The industry is the connecting link knitting the interests of oil producers and refiners into a much closer relationship than ever existed .prior to its inception and development. The relation between the producer and the refiner of petroleum prior to 1910 was. a rather antagonistic one in a commercial sense. It was to the interest of the producer of crude petroleum to sell it for a maximum consideration; the refiner's interest was to obtain the same product for a minimum consideration; therefore, each side of the business transaction retained within his own hands as far as possible the trade secrets of his business. Each side maintained an attitude of cold-blooded business sympathy only for the other. Cas-

Jan 12, 1917