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By AIME AIME

HE State of Utah has an area of 84,990 sq. mi., and like other inland states in the West its population, although steadily increasing, is relatively small. The fact that it is a state possessing vast mineral resources is attested by a careful study of statistics which have been compiled by Federal and State investigators. Some idea of the extent of these resources and the degree of development of a particular state or region may be gained by such a study, but in the case of Utah statistics and other available information fail to portray completely the true extent and value of its existing metallic and non-metallic resources. The State is probably more widely known for its production of metallic ores which has placed it in an eminent position among the metal mining states of the Nation.

Jan 1, 1925

EXECUTIVE COMMITTEE OF THE BOARD OF DIRECTORS W E WRATHER, Chairman A B KINZEL -EARLE E SCHUMACHER DONALD H MCLAUGHLIN - JOHN R SUMAN FINANCE COMMITTEE OF THE BOARD OF DIRECTORS ERLE V DAVELER, Chairman PHILIP KRAFT - CLYDE E WEED

Jan 1, 1952

By John S. Brown

IN 1925 the writer undertook a detailed statistical study of all producing areas in the Joplin district as a basis for evaluating programs and measuring objectives. For this purpose, the published figures in the yearly volumes of Mineral Resources were used, supplemented for earlier years by publications of the Missouri Geological Survey and other local and less official sources. When all else failed, the available data were projected backward to hazard a reasonable guess as to the unrecorded early output of important areas. Fortunately, the proportion of such prehistory production is not a large factor in any of the totals. These results were used during the next few years to measure the relative importance of various producing areas and to predict the peak period of development of the all-important Picher field. For the purpose of this review, the charts have been completed to the end of 1950. During World War 11, the U. S. Bureau of Mines became interested in a similar study and issued comprehensive statistical tabulations of data up to 1945 ( Info. Circular 7383), which have been checked against the figures used herein. This tabulation, however, does not include all the earlier data used by the writer nor does it offer any estimates of the wholly unrecorded era in the beginnings of the earlier camps.

Jan 9, 1951

* Kennecott Copper Corp. gets Charles R. Cox as president on Jan. 1. Mr. Cox is resigning his position as president of Carnegie-Illinois to take the new post with Kennecott, left vacant by the death of Mr. Stannard in September. •The ECA signed a contract in December to advance X3,600,000 to Newmont Mining Corp. to aid development of lead and zinc mines in French Morocco. The funds are to be repaid in lead and zinc for the United States' stockpile over a period of seven years. The mines are owned by the Societe des Mines de Zellidja, with which organization Newmont is associated. • Under the direction of John M. Brooks, Jr., general manager, the Matahambra mine in Cuba, will probably produce sufficient tonnage to make 4 million lb of copper per month during 1950. The grade is presently running between 7 and 10 pet. •S. H. Ash reports that the fatality rate per million-man-hr for the anthracite industry for 1949, through November, is 0.78. This is 15 pct better than that achieved during 1948, which was the lowest fatal injury rate in coal mining history. The first full year on record without a major disaster was recorded in 1949 (p. 34). •The Atomic Energy Commission has authorized the production of 200 lb of uranium metal for use under AEC license in non-Commission research projects. •A national survey of projected 1950 purchases of new machine tools, machine tool accessories, materials handling equipment, etc., just completed by the American Society of Tool Engineers reveals that, of the companies reporting, 80 pct state that they plan to buy either more equipment or the same amount as in 1948. • Armour Research Foundation is conducting investigations for the use of clay and shale deposits to make lightweight aggregates. The material is heated until it expands and forms material suitable for mixing with cement which it is hoped will be lighter, stronger, have better insulating qualities and will lower the cost of concrete. •In the first six months of 1949 the bituminous coal miners' average hourly earnings were $1.94 -as compared with X1.392_ national average for all manufacturing. Average annual earnings of full-time employees in the bituminous coal mines in 1948 were $3387 as compared with $2809 for all industry. •LaSalle Business Bulletin reports: "year ends on a rising trend in industry and trade ... nearly record-breaking demand from almost all sources keeps business high... most indicators but little below postwar peak... forces keeping activity high arestill powerful--changes in general business conditions likely to be slow and moderate." •Office of Internal Trade of the Commerce Department requests that technical data significant to the national security which is to be sent outside of the United States be submitted to it for an official opinion on the desirability of transmitting such information. This voluntary compliance program is part of our national security control. • Blast furnace slag reduced to 12 to 16 mesh is being used for sanding track at the Mont Coal mines of Armco. The slag replaces silica sand which caused silicosis. It has proved so effective and cheap that tests are being made to use the slag for rock dusting.

Jan 1, 1950

By V. R. Garfias, R. V. Whetsel, J. W. Ristori

Preliminary estimates indicate that world consumption of petroleum and related fuels in 1938 will be close to 1,908,000,000 bbl., or approximately 7,000,000 bbl. less than in 1937. This total does not include military consumption in foreign countries, which for obvious reasons is not made public. Foreign military consumption in any one year, however, is approximately represented by the difference between the total production of petroleum and related fuels and the "partial total" consumption above noted, after adding any decrease, or subtracting any increase in stocks in the United States. Fig. 1 illustrates this "difference" and shows that in 1937 and 1938, owing to the wars in China and Spain and the possibility of armed conflict in Central Europe, foreign military consumption—and possibly additions to foreign stocks—increased nearly 70,000,000 bbl. in 1937 over 1936 and remained at this high rate throughout 1938. No official information on foreign oil stocks is available to the writers. Table 1, recently published, purports to give the oil in storage in some of the European countries, but it is not known whether the figures include oil stocks for military purposes. It should be noted that with the annexation by Germany of Austria and part of Czechoslovakia the consumption of the country has increased to 53,000,000 bbl., which is about 36,000,000 short of the German produc-

Jan 1, 1939

By J. W. Ristori, R. V. Whetsel, V. R. Garfias

Preliminary estimates indicate that world consumption of petroleum and related fuels in 1938 will be close to 1,908,000,000 bbl., or approximately 7,000,000 bbl. less than in 1937. This total does not include military consumption in foreign countries, which for obvious reasons is not made public. Foreign military consumption in any one year, however, is approximately represented by the difference between the total production of petroleum and related fuels and the "partial total" consumption above noted, after adding any decrease, or subtracting any increase in stocks in the United States. Fig. 1 illustrates this "difference" and shows that in 1937 and 1938, owing to the wars in China and Spain and the possibility of armed conflict in Central Europe, foreign military consumption—and possibly additions to foreign stocks—increased nearly 70,000,000 bbl. in 1937 over 1936 and remained at this high rate throughout 1938. No official information on foreign oil stocks is available to the writers. Table 1, recently published, purports to give the oil in storage in some of the European countries, but it is not known whether the figures include oil stocks for military purposes. It should be noted that with the annexation by Germany of Austria and part of Czechoslovakia the consumption of the country has increased to 53,000,000 bbl., which is about 36,000,000 short of the German produc-

Jan 1, 1939

By Walter E. Mingramm

The construction of rescue-apparatus on the principle of furnishing the wearer with air from a tank containing it under high pressure was given up by inventors about 20 years ago. Such an apparatus must supply continuously, for not less than two hours, nearly 50 liters of pure air at atmospheric pressure per minute, or a total of 6,000 liters (210 cu. ft.); and a cylinder containing this amount of air, under 2,000 lb. pressure, would weigh 180 lb. or more. Although apparatus has been recently constructed utilizing liquefied air, no experiments have been made to determine the regularity with which the air is generated, nor has its chemical composition been determined. Moreover, the chief objection to such an apparatus is the difficulty and cost of keeping on hand a large quantity of liquefied air. The system of furnishing the wearer of a breathing-apparatus with air which has given the best results, and has found

Jan 1, 1909

Curiously enough, considering the relative accessibility of the two places, coal was reported at an earlier date in Saskatchewan than in British Columbia. Henry and Thompson were on the Saskatchewan River in February 1811, and on the 4th of that month recorded, while on Jack's Branch of North Brook, "I observed in one of the bends on the north side a bank of yellow clay, on which there appeared several horizontal veins of pure coal, of the best quality I have seen along this river." Later at Rocky Mountain House it was said: "a quantity of coal is tumbling into the water, as the current washes away the earth underneath. This coal abounds along the Saskatchewan, in some places forming solid beds several feet thick for several acres, which are washed by the river. In its pure state our smiths use it for the forge with equal proportions of charcoal made of birch or aspen, which answers every purpose for making and repairing our axles and other tools."1 It is needless to say that it was many years before this coal was used for any commercial purposes. Coal was first found on the northern end of Vancouver Island in British Columbia in 1835 at Beaver Harbor, where later Fort Rupert was established, where Indians had advised some of the Hudson Bay Company officials it would be found.2 The coal was used by smiths, and later on by the steamer plying along the coast.3 A report to the government in 1845 called attention to the coal reported in the neighborhood of Puget Sound and on the Cowlitz River, and that probably the samples used by the Hudson's Bay Company were obtained from the surface and. were not good. On September 7, 1846 a report on the coal situation was submitted by Ogden and Douglas, and a naval vessel was sent to investigate the report and was loaded with 62 tons dug out by the Indians, the seam outcropping along the shore.2 In 1847 some samples were sent to England by a returning war vessel. In 1849 the Hudson's Bay Company established a

Jan 1, 1942

By Ronald C. Whiting

SINCE the advent of what has been aptly called "chemical flotation," about 1920, the number and complexity of the various chemicals used in practice have increased enormously. Over 300 patents have been issued dealing exclusively with flotation reagents, and many of these embrace from two or three up to a score or more of specific compounds. The exact number of compounds actually finding a practical use in flotation would be difficult to determine, though the U. S. Bureau of Mines gives an annual list by groups.

Jan 1, 1938

By Edwin Ludlow

ONE of the most unusual features in connection with the strike of the union coal miners in the bituminous fields, now in its sixth week, is that the public interest seems to have completely died out. There is nothing on the front page and very little on any other page of the daily newspapers in connection with the strike. The United Mine Workers' officials must be rather disappointed to find that the only way in which they are being featured in the papers at present is in the reports of the trial for treason that is going on in Charlestown, West Va., against the local leaders of that organization for their responsibility in connection with the attack of the miners' army last summer against the non-union mines of Logan and Mingo Counties. Recent reports state that there are 13,000 cars of coal standing on the sidings at union mines for which no billing has yet been found. The output of the non-union mines has been gradually increasing but has never reached the maximum that they are capable of producing, owing to their inability to obtain enough orders to make it possible to run full operating time. The, present output is estimated at, 4,500,000 tons a week. It is possible, with a full car supply and full demand, to bring this output up to approximately 6,000,000 tons per week, and it is very doubtful whether, at this season of the year when probably there is less consumption of coal than, at any other season, the requirements of the country are greater than the 6,000,000 tons which the non-union mines are capable of producing. It would appear, therefore, that there is no immediate prospect of any settlement of the bituminous strike, and there is certainly no reason why the operators of the union mines should show any anxiety to begin operations as long as they have unbilled coal standing on their sidings.

Jan 6, 1922

By Charles R. Keyes

I. Introductory,.......... 185 II. Hypotheses oF the Origin of OzaRk Ores..... 186 1. General Considerations........ 186 2. Schmidt-Leonhard and Gage View...... 187 3. Jenney Opinion.......... 187 4. Posepny Idea,.......... 188 5. Winslow-Robertson Hypothesis....... 188 6. Branner Proposition......... 189 7. Keyes Statement.......... 189 8. Van Hise-Bain Theory........ 190 III. Requirements of an Adequate WoRking-Hypothesis,... 190 IV. GeneRal Geotectonics of the OzaRk Region.... 192 1. Salient Aspects.......... 192 2. Geologic Formations......... 192 3. Character of Faulting...192 4. Extent of Flexing......... 193 5. Unconformity Inequalities....195 6. Warping of Strata...195 V. Classes of Ore-Deposits... 196 VI. Vadose ORe-ConcentRation,........ 197 VII. GeogRaphic DistRibution of the Ore-Bodies,... 199 VIII. Relation of ORe-Deposit to Geologic Structure... 201 1. General Occurrence of Ore-Bodies in Basins.... 201 2. Deposits of the Central Missouri District..... 203 3. Deposits of the Southwestern Missouri District.... 203 4. Deposits of the Northern Arkansas District... 305 5. Deposits of the Southeastern Missouri District.... 206 6. Synclinal Ore-Deposits of Other Districts.....207 7. Significance of Ore-Troughs in Prospecting... 209 8. Origin of the so-called Synclines,...210 9. Significance of the Cross-Bars of Joplin..... 213 10. Relation of Ore-Run to Ancient Relief-Features,... 215 IX. Direction of GRound-Water Circulation..... 216 X. VeRtical Range of Workable Ore-Bodies,... 218 XI. Oscillation of Ground-WateR Level...... 219 XII. Relations of Ore-Bodies to Lithoclasic Features,.. 220 XIII. PRimaRy Source of Ore-Materials,...... 220 XIV. Zone of Ore-Enrichment,......... 222

Jan 1, 1910

By M. King Hubbert

THE growth of human knowledge is an evolutionary process. His-torically our separate sciences came into existence as people became interested in various apparently unrelated domains of phenomena, and in this manner we acquired the sciences of physics, chemistry, astronomy, biology and geology. As various of these sciences became established, cognizance of them came to be taken by the universities and in this manner there arose the traditional departments of physics, astronomy, chemistry, biology and geology of our American universities. As there was no particular rationality in the boundaries separating the various sciences, in the university departments the jurisdiction of each has assumed quite arbitrary limits. In the domain of earth phenomena the first science to grow up was that of geology, which arose originally from the activities of the collectors of rocks, minerals and fossils. Thus geology evolved as a descriptive science dealing with directly observable terrestrial phenomena for which elementary rational explanations were offered. The traditional treat-ment of phenomena by the science of geology has rarely been with more than an elementary regard for the fact that these phenomena were also phenomena of physics and chemistry. Since the latter part of the nineteenth century, a new approach to terrestrial phenomena has been emerging and becoming of so great a significance that it can no longer be ignored. This approach has been made by people trained primarily in the sciences of physics and chemistry, who have investigated terrestrial phenomena as constituting phenomena of, their respective sciences. In this manner we have acquired the so-called "borderland sciences" of geophysics, the physics of the earth, and of geochemistry, the chemistry of the earth. Neither of these fields is new, having arisen chiefly at the hands of European investigators during the latter part of the nineteenth century. The European uni-versities have long since given official recognition at least to geophysics, by the establishment of departments or institutes of geophysics, which are on a par with ,the university departments of the other sciences.

Jan 1, 1938

By Walter Herd

Fox the past eight years No. 2 mine of the Cumberland Railway & Coal Co., Springhill, Nova Scotia-a subsidiary of the Dominion Coal Co., Ltd.-has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent that some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Department of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of -Public Works and Mines, Nova Scotia. Prior to 1925, the room and pillar method was employed and in January of that year (there being a cessation of work from March to August due to labor troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence, had not been experienced. In the interval development work for longwall retreating below the 5900-ft. level was vigorously- pushed. This longwall retreating system was suggested by Mr. Rice as a possible remedy and was heartily endorsed by the company officials. This paper describes the conditions and happenings subsequent to Mr. Rice's report and more especially the results with the longwall retreating system of mining under the peculiar circumstances pertaining to mining. No. 2 Seam, Springhill, at depth, and records the 'conclusions which experience with several severe bumps under this mode of extraction would suggest. Except where necessary to make the paper intelligible as an entity any duplication of Mr. Rice's report will be avoided.

Jan 1, 1929

By John V. Beall

GOING west from Denver on Route 6, the direct road to Grand Junction, one gets the first glimpse of mining a few miles east of Denver near Idaho Springs where the workings of defunct gold mines are visible on the sides of mountains along the highway. One enterprising company is turning a profit by showing tourists through the mine and mill and then selling them gold samples on the way out. We have always known that mining people are ingenious, but this proves it. About five and a half hours fast driving west from Denver brings one to Rifle, Colo., which is the site of the oil shale mine, retorting plant, and refinery of the U. S. Bureau of Mines. As you drive up to the mine, you can see a portal high on the face of the cliff in front of you where the mine surface plant literally hangs by its toenails. Below, the retorting plant and refinery gleam in the sunlight. Up at the mine, Fred Wright will show you how the oil shale is extracted in two benches (a third bench would be used for commercial mining) by the room-and-pillar method. In mining the top level, an underground crew of thirteen men have been able to produce 1500 tons of shale in each eight-hour shift. To do this, the mine is thoroughly mechanized. The mining method is de- scribed in the September issue of Mining Engineering.

Jan 1, 1949

By K. W. Nelson, John N. Abersold

INDUSTRIAL hygiene has been defined by Patty' as "the science and art of recognizing, evaluating, and controlling potentially harmful factors in the industrial environment." This definition implies thorough study of operations, evaluation of potentially harmful factors through air sampling, micro-analyses and other means and finally, appropriate medical and engineering control wherever indicated. The prevention of industrial health injuries is a vital part of operations of American industry today. Progress and interest in this field has increased steadily for many years, the most rapid progress having been attained, perhaps, during the last three decades. It is significant to note that there are now official agencies in 46 states actively concerned with industrial health problems and that a western field station has been established recently in Salt Lake City by the U. S. Public Health Service to augment its industrial hygiene services directed from headquarters of the National Institute of Health, Bethesda, Md. Many of the larger industries have found it advantageous to establish their own industrial hygiene departments. The American Smelting and Refining Co. is a world-wide organization engaged in the mining, smelting, and refining of lead, copper, zinc, silver, gold, by-product metals, including cadmium, arsenic, and others. In the United States there are 13 smelters and refineries, 11 secondary smelters or foundries, and a number of mines. Approximately 9000 workers are normally employed. It has long been the established company policy to seek out occupational hazards and provide safeguards for employee health. Protective equipment has been supplied to individual workers and exhaust ventilation installations have been in use in some operations for more than 40 years. All of the major units have their own medical departments which provide employees with excellent medical and hospital care. In 1937 full scale industrial hygiene studies were undertaken at the Selby Plant and were extended to most of the other smelters during the next three years. In 1945 the Department of Hygiene was organized with Professor Philip Drinker of Harvard University as Director and with Dr. S. S. Pinto as Medical Director. The department is responsible for coordinating and maintaining a program for the good health of all employees from top management down to the lowest paid day worker. It is essentially a service organization serving all of the United States plants regardless of location or size. Full and part-time physicians employed in all of the company's American plants and working in close cooperation with the Medical Director are responsible for de- termining the state of health of all the employees and giving treatment when necessary. In general, medical care is confined to accidents or illnesses occurring while the men are on the job. Among the duties of the doctors is the making of careful physical examinations of new employees and routine check-ups of old employees. In addition to medical care a primary responsibility of the department is the prevention of occupational illnesses. In this the main concern is with the working environment in relation to its effect on the worker. Environmental factors may be dusts, fumes, gases, toxic materials, heat, humidity, radiation, or noise. The objectives are: (1) Immediate control of these factors through the education of the worker, through providing the wearing of respirators or other protective devices, and through careful medical examinations and regular analysis of urine specimens; (2) a long range control program which may be accomplished by local exhaust ventilation, wetting of materials, changes in metallurgy, changes in methods of handling, or by use of special devices and special equipment. To accomplish these objectives a fine industrial hygiene laboratory was built in Salt Lake City and equipped to do routine and experimental work. Trained and experienced industrial hygienists obtain the facts by making frequent hygiene surveys. These surveys include tests of the air, studies of all processes, and careful investigation of ventilation, lighting, and general working conditions. Except in emergencies, the air contaminants and often the substances handled by the worker are sent to the laboratory for analysis by chemists and technicians specially trained in industrial hygiene methods. The findings are evaluated in terms of limits recommended by various State and Federal agencies, and in light of all available medical data. The methods used for studying the working environment involve all of the usual chemical and physical procedures employed in industrial hygiene. The Impinger, electric precipitator, thermal pre-cipitator, and filter paper sampler have been used to collect atmospheric dust and fume samples. Of special interest here is the filter paper sampler, shown in Fig. 1, which was developed by Dr. Silver-man at Harvard University. The instrument has been improved and is used very extensively in field studies. A water manometer connected behind an orifice is used to determine the rate of air flow. Calibration is effected by use of a standard gas meter or rotameter. The dust or fume is collected on a filter paper clamped between two rings, as shown in Fig. 2. The filter paper, such as Whatman No. 52, collects both dust and fume with a very high efficiency. The instrument is very convenient and easily transported. The solids collected on the filter paper are analyzed in the laboratory usually by use of a polar-ographic procedure. By this procedure it is possible to measure quantitatively in a single analysis the

Jan 1, 1952

PRESIDENTS DAVID THOMAS 1871 R W RAYMOND 1872-1874 A L HOLLEY1875 ABRAM S HEWITT 1876 T STERRY HUNT 1877 ECKLEY B COXE 1878 - 1879 WILLIAM P SHINN 1880 WILLIAM METCALF 1881 RICHARD P ROTHWELL 1882 ROBERY W HUNT 1883 JAMES C, BAYLES 1884-1885 ROBERT H RICHARDS 1886 THOMAS EGLESTON 1887 WILLIAM B POTTER 1888 RICHARD PEARCE 1889 ADAM S HEWITT 1890 JOHN BIRKINBINE 1891-1892 H M HOWE 1893 JOHN FRITZ 1894 J D WEEKS 1895 E G SPILSBURY 1896

Jan 1, 1923

The Colorado Society of Engineers, Cooper bldg , Denver, Colo C M Lightburn, Secretary. The official organ of the Colorado Society of Engineers is the Engineers' Bulletin, issued monthly. This magazine contains articles on a wide variety of subjects, as do most technical magazines. Several years ago the engineering societies of Colorado turned over to the Public Library of Denver their technical libraries and the Public Library now has a Technical Department serving engineers This library has been enlarged and is supported by the state as well as the engineering organizations of Colorado A bimonthly New Books List is sent out from the Technical Department to all engineers on the mailing list. Books will be lent for the cost of transportation The Technical Department endeavors to keep a file of all state and some foreign publications on mining, geology and engineering Effort will be made to borrow from other sources, any publications which are not on file. The Technical Department does research, compiles bibliographies and answers reference questions. Photostatic copies will be made, at a price, of any publications which can not be loaned Address The Public Library, The City and County of Denver, Technical Department, Denver, Colo Malcolm Glenn Wyer, Librarian.

Jan 1, 1933

Jan 1, 1946

By L. W. Saperstein, Y. J. Wang

The development of computer programs to solve complex ventilation networks has reached a point of refinement where these programs become a necessary tool of the ventilating engineer. Such a program is presented. This program has an increased efficiency over its predecessors; it also includes the important facility of fixed quantity branches. This is in addition to the earlier capabilities of free-splitting, internal or external fans, and natural ventilation pressures. The program is written in Fortran IV with double-precision arithmetic and is listed here. Sample problems with input and output are also given. The recent, and presumably continuing, official interest in mine safety is bound to result in more stringent control requirements for ventilation. Anticipating this requirement, the Dept. of Mining, The Pennsylvania State University, has developed a computer program for the solution of complex mine ventilation networks. It is the opinion of this department that the program has sufficient merit to warrant its use in normal industrial operating conditions. Although the undergraduate mining engineering students of this department are routinely trained to use the program, it was felt that this training did not present a fast enough means of dissemination; consequently, this paper was written. The conception of the program is not new;1; however, the present version incorporates features that changes it from a scientific endeavor to a useful operating tool. These features include those of earlier programs, such as free-splitting, external or internal fans, and natural ventilation processes plus the important ability of handling fixed quantity branches, and of increased efficiency giving reduced cost. The facility for fixed quantities will be discussed in more detail. The solution of any network depends upon satisfying Kirchchoff's laws. These state that the sum of flow at any junction is zero, and that the sum of the pressure drop in branches totals the pressure drop in the mesh constituted by those branches, that is that the pressure drop around any mesh is zero. The terminology is derived from Synge," and is, in fact, that used by Topologists. A branch is any airway of uniform characteristics; a junction is where two or more airways meet (the minimum number of two airways is useful for describing the point where a low resistance airway changes into a high resistance one due to some physical constriction); a mesh is a path, along some branches, that returns on to itself, but does not need to traverse the same branch twice in order to do so; and a tree describes all those branches in a network which, while connected through all the junctions, do not form any meshes. Obviously the branches-in-tree are open-ended and can be shown to be one less than the number of junction (J-1). The branches-out-of-tree, also called basic branches, are equal to the number of basic meshes and are M = N — J + 1, where M is the number of meshes and N is the number of branches. The major difference between this network and an electrical one is that the law attributed to Atkinson for pressure drop is utilized rather than Ohm's law. Atkinson stated that the pressure drop (potential) is equal to a resistance factor multiplied by the quantity squared. This is written H = RlQlQ where H is the head loss. Q? is written in this factored fashion so that H will always have the same sign as Q. A negative sign is used to indicate that flow in a branch is opposite to that of its containing mesh. A mesh takes the direction of its basic branch. Utilizing Atkinson's law in Kirchchoff's second law and bearing in mind that the first law must remain satisfied, the program will determine all quantities, or head losses as they are related, for the branches of the network. The program uses a Geuss-Seidel form of in-teration, starting from an arbitrary Q and using a correction factor of the type first suggested by Professor Hardy Cross' that will handle the nonlinear equation of Atkinson's law. A fuller description of the interative process is included in Wang and Hartman.' Iteration continues until the correction factor is less than or equal to a preset error (E) or until a maximum number of iterations (MAXIT) have been reached. Utilizing an E of 50 cfm, sample problems have had rapid solutions. Rapidity of solution is also ensured by the method of selecting meshes and basic branches. This is done by the computer, which chooses the highest resistance branches, fixed quantity branches, and those containing fans, as basic branches. Natural ventilation pressures are handled as fans of constant pressure and may be assigned to any branch. The computer will generate a fan characteristic by polynominal fitting if a few operating points from the desired fan are input. A fan may be placed in any branch of the network, except those with fixed quantities. The strength of the present program over its earlier versions is its ability to handle fixed quantity branches. This means that certain branches can have their quantity determined, or preset, by the ventilating engineer. Operating under this constraint, the program will analyze the network and output the pressure change necessary to achieve this desired quantity. A call for positive head loss would require an auxiliary fan; negative head loss would require a regulator. This represents a powerful tool for the ventilating engineer who must insure that certain quantities of air pass across the operating faces or through working stopes. McPherson6 suggested that a ventilation program would be useful for determining in advance which branches were receiving inadequate air, and that subsequent calculations would then indicate the necessary corrections. The present program makes these corrections. Thus the mine manager can know immediately the consequences of changes to his system;

Jan 1, 1971

By AIME AIME

THE accompanying photograph: submitted by C. L. Bransford, assistant district manager of the Republic Steel Corp., in Birmingham. Ala., shows the remains of the old Tannehill blast furnaces, one of the first furnace plants in the South. They were built by Moses Stroup and operated during the Civil War period, when cannon balls were cast there. The record day's run of this furnace plant was said to be 30 tons of iron. The furnaces were fed by a water-wheel-operated bellows and used charcoal, a product of the neighboring forest. They were first owned and operated by the Pioneer Mining & Manufacturing Co., that later became the Republic Iron & Steel Cu., and subsequently the Republic Steel Corp. in that district.

Jan 1, 1936