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By C. B. Murray

"OUR experience from time immemorial has been that the furnace sampler and analyst usually find one or two, and sometimes more, points less iron than the Lake Superior shippers, but, fortunately, their contracts are `iron bound'; and, generally speaking, analyses at this end are practically useless, for we are obliged to settle on basis figured out to a half dozen decimals, and, as a rule, without recourse in the event of flagrant discrepancies between the two analysts." The above is an extract from a letter received by the writer of this paper from the President of an iron company, discussing the question of sampling. It so well expresses the opinion of many blast-furnace owners and managers that it seems a suitable text for a discussion concerning the need of uniform methods of sampling. If all railroad cars were loaded the same, if all stock piles were the same shape, and if ore was received regularly each day, the problem of sampling would be comparatively simple. The conditions, however, vary widely at different places, and at the same place from day to day, and it is probably impossible to determine upon any one method of sampling which will apply at all times and in all cases. However, it would seem as though some general principles might be suggested which would tend to overcome these wide differences in samples of the same thing. The sampling of a cargo of iron ore begins at the breast of ore in the mine. The ore is sampled from the mine cars, from the stock piles, and from the railroad cars at the mines. At the lower Lake ports the ore is practically all sampled from the boat, occasionally from railroad cars. At the furnaces, the ore is nearly all sampled from railroad cars and occasionally from stock piles.

Jan 1, 1914

By Joseph Pogue

ANY mechanism, either natural or artificial, for regulating the func-tioning of a given unit in the general economy must operate toward the maintenance of equilibrium if it is to survive. The petroleum industry, concerned as it is with the production of a natural resource of specialized character, is surrounded not only by the economic factors common to other industries but by an extra set of unique elements centering about the fugitive character of crude petroleum under conditions of competitive development. The term equilibrium, therefore, so far as the oil business concerned, involves a combination of economic and physical factors: the first set having to do with supply, demand, costs, profit margins, purchasing power, and the like; and the second, with underground pres-sures in oil pools, efficient rates of extraction, and all other aspects of engineering that may be summarized by the familiar term "conserva-tion." The two categories, in fact, are not as clearly divided as the foregoing statement would imply, for in practice it will be found that the economic and physical aspects have a pervasive interaction and interrelationship. If the development of the petroleum industry in the United States is examined from its inception in 1859 down to the present, it will be found that, beginning about 11 years ago, a new mechanism for regulating the production of crude petroleum made its appearance. Prior to this recent period, the production of this raw material was determined by competitive forces operating without outside restraints. At present the output of crude oil is subjected to supervision by regulatory bodies in most of the oil-producing states, which impose upon the operators certain conditions having to do with the manner and rates of production. Thus, in the space of a decade, the mechanism for producing crude oil has changed from an automatic to a designed procedure called proration. And in its short history this method has been marked by a rapid evolution in its nature and incidence, with progressive changes still under way.

Jan 1, 1938

By Oliver Ralston

DURING experimental study on the separation of a zinc concentrate from the heavy sulfide ores of Jerome, Ariz., a great deal of attention has been given to proper activation of the sphalerite content of the ore. The sphalerite at Jerome contains enough iron to class it as a marmatite, as picked specimens have only about 60 per cent. zinc, whereas pure zinc sulfide contains 67 per cent, zinc. This marmatite in large pieces is black in color, but in dry powdered state is brown. A flotation froth made from it has a silvery black luster in comparison with a brassy luster caused by chalcopyrite which occurs in the same ores. The sample used in most of the experiments described below consisted of about 3000 lb. of diamond-drill core from the zinc-bearing orebodies of the United Verde mine, and had the following analysis: PER CENT. PER CENT. Oz. PER TON Cu 0.695 A1203 0.83 Ag 1.30 Zn 6.17 S...:: 43.35 Au 0.02 Fe 36.23 CaO 0.46 Si02 9.27 Mineralogically, this analysis is calculated to the following, which is in agreement with the microscopic examination: PER CENT. PER CENT. Chalcopyrite 2.0 Schist 3.2 Marmatite 10.32 Quartz 8.2 Pyrite 73.0 Calcite 0.9 All samples were ground in a laboratory ball mill in order to leave about 3 per cent. on a 200-mesh sieve, fine grinding being essential to liberate the minerals in the ore. Most of the Jerome ores are so intimately crystallized that reasonably complete unlocking by grinding does not take place until 800 mesh is approached. Therefore, the 200-mesh grind adopted contains a considerable amount of locked mineral grains, but not so much as. to render impossible the preparation of commercial grades of concentrate:

Jan 1, 1929

By W. J. Sharwood

The assay or estimation of the total gold content of an ore presents little difficulty, when circumstances permit of securing a thoroughly representative sample. The general practice has been fairly standardized, and such errors as occur in the results obtained are for the most part attributable to the methods of sampling rather than to those of assaying, while duplicate assays made by skilled workers usually agree closely. When it is a question of estimating the "free" or amalgamable gold of an ore, as opposed to the total gold, there is but little uniformity in the methods employed by different workers, and often equally little in the results obtained when duplicate determinations are attempted, no satisfactory standard method having been generally adopted. The methods in use are of two general types—"panning" and "amalgamation." Panning For the estimation of the value of the visible gold by panning or washing, a weighed sample may be taken, ranging from an ounce to several pounds; a kilogram or 2 lb. is a favorite quantity for laboratory tests, while a prospector often uses a full miners' pan, say nearly 20 lb. or 10 kg. In the case of rich quartz, ground to about 30 or 40 mesh, a Mexican horn is convenient, using 1 to 8 02;. of material, and a 6-in. frying pan is favored by many prospectors in dry districts. Bateas, plaques, and dishes of various patterns are used for the same purpose. With these, fairly close results may be obtained by using for ocular comparison standards consisting of weighed amounts of gold of similar character as regards purity, fineness of division, and the general shape of the particles, which standards are preferably obtained from gold of the same locality, or the same deposit, as the ore or gravel being tested. Men working in one particular district sometimes become surprisingly expert in thus judging the value of an ore by the eye, the weights of both ore and gold being guessed. On the other hand, many have been led to overestimate the value of ore and gravel from unfamiliar localities, where the gold has been very finely divided or of unusually high silver content, and a novice may

Jan 1, 1916

By Dewitt T. Ring

Lack of reliable detailed production figures for earlier years, together with the loose nomenclature in reference to producing horizons and the application of the term "field" without any definite meaning or restriction, has made it impossible to gather statistical data suitable for the Institute's form. In common with all other producing areas in the United States, Ohio has felt severely the economic ills of the entire industry during the past year. With overproduction, not only of crude but also of refined products, going on throughout the country, the price structure as a direct consequence has weakened on Ohio oils. Valuable crude is being sold at a big loss today because producers arc willing to, and do, sell more than the market can absorb. The axe hangs heavy over the heads of Ohio producers, and will until something constructive is done to keep supply in proportion to demand. This not only applies to Ohio but to the entire industry. Production of Pennsylvania grade in Ohio was under 50 per cent proration, which has been in effect since Oct. 1, 1937. Three price cuts since February have lowered the posted price from $1.70 to $1.18, a 30 per cent reduction; other grades were less drastically reduced. Pipeline storage facilities were limited; many producers were faced with the problem of providing their own storage or the risk of ruining their wells. If they wanted to pull and abandon wells, there was no market for junk equipment. Many employees have been cut to half time and in a number of instances their services entirely dispensed with. Summary of Production and Drilling Both oil and gas production in the state during 1938 showed a definite decline over the previous year. (A table showing production by years from 1876 through 1937 was published in Vol. 127 of the Transactions.) The total production of crude oil in the state for 1938 was 3,357,914 bbl., as compared with 3,654,000 bbl. in 1937, a decrease of 7.1 per cent. At

Jan 1, 1939

By Richard Moldenke

ONE of the little-known characteristics of cast' iron, which neverthe-less has an important bearing on results where accuracy in machining-is essential, is the ability of this material to ease up internal strains when. .allowed to remain quiescent for a more or less extended period of time. At seems as if the molecules in such a casting, by virtue of their "mobility,? can adjust their relative positions to an extent sufficient to overcome some of the existing stresses. The following instance will perhaps give a fair idea of the condition a casting may he in when just shaken out of the sand. A very large sheave-wheel, after shaking out, was taken' outdoors to be, cleaned and made ready for turning up. It was leaned against the side of the building, but before much could be done an arm tore apart with a loud report. Investigation showed that the sun had been shining on the upper rim, this adding a slight strain to those already existing within the arm and thus overbalancing the strength of the metal in tension. Had this sheave been kept under cover for a while, or at least until machined, the-strains., would have eased off sufficiently to allow the sun to look upon it without disaster. It will not be necessary to multiply examples. Every engineer knows the danger of water-hammer in pipe lines, particularly if the latter are of cast iron. Every mechanic knows, or should know, that it is not good to strike a fitting that is under steam pressure. It will be necessary to say a few words on the "internal- strains" in castings-the so-called "casting strains" we hear so much about. We all know that to get a casting reasonably true to the dimensions wanted requires a slightly larger pattern. The usual allowance for gray iron is 1/8 in. to the foot (1 cm. per meter) and ¼ in. to the foot (2 cm. per meter) for white iron (all dimensions). This reduction in length, breadth and thickness in a casting is erroneously called "shrinkage." It should be called "contraction," as for practical purposes. it is simply the difference .in dimensions of the casting red-hot and cold.

Jan 2, 1917

By John D. Ridge, Robert C. Barwick

In contrast to international trade in lead, a much larger percentage of zinc shipped from one country to another is shipped in concentrate form. In 1952 international commerce in zinc concentrates accounted for 37 pct of world zinc mine production, and of the total zinc which traveled from one country to another, slightly more than 65 pct was in concentrates. The comparable figures for lead, given in Part VI, were 16 and 27 pct. Of the zinc mined in the world in 1952, 56.6 pct entered international trade; the analogous figure for lead was 57.4. This similarity in proportion of production traded is paralleled by a similarity in sources of exports. The three leading exporters of zinc in all forms in 1952 were Canada, Mexico, and Australia, in that order; the three largest exporters of lead were Mexico, Australia, and Canada. In contrast to the 86 pct theoretical maximum in lead concentrates, the maximum for zinc concentrate is only 67 pct. On this basis alone, it would be reasonable to expect that more zinc would be traded as zinc metal than lead as lead metal. Actually, the reverse is true. Less than 28 pct of the lead in international commerce moves as lead in concentrates, while 65 pct of the zinc so traded is as concentrates. Mexico, a country which has attempted to retain as much metal processing activity as possible within its own borders, has negligible exports of lead in concentrates.

Nov 1, 1955

By J. W. Harden

AT our meeting in October last we saw in operation at Pittsburgh, the comparatively modern process of the utilization of small coal by washing, by an arrangement similar to that of Berard or Morrison. The small coal washed was that of an old pile, the refuse of the mining of the Pittsburgh bed, and which had long lain uncared for. Value was thereby restored to it when it was converted into a very good coke. This circumstance led to comments on the mountains of broken coal lying wasted, and in its present condition worse than useless, in the neighborhood of the mines of the Wyoming Valley, though they are not confined to that district. Some things were said condemning the course which produced it, some were left unsaid. Of a system that destroys one-half the coal-bed in producing the other half there can, however, be but one opinion. Schemes have been suggested for the utilization of present accumulations which, if successfully applied, would in so Far be beneficial. More than ordinary attention is now being given to the same subject in England ; a Mr. Barker has invented a means by which he amalgamates the "dust," too fine to burn in ordinary grates, with a composition he calls "diamond cement," producing blocks of coal said to resist water, both hot and cold, and which a smart blow will only break to pieces, not cause to crumble. But any scheme less than the one which will prevent the wasting of coal, which still goes on, though that involves the aban- donment of the breaker, will only be one of expediency; and the latter can only be done by the aid of the consumer. But the wasting of coal is not alone with the breaker; much is made in the mine. The cause is not far to seek ; the remedy is with capitalist and owner. Owners and consumers then are alike interested, and they have it in their power, in the one case, to mitigate, in the other, almost entirely to remove the cause of the evil. Of consumers there is one in every

By Joseph E. Pouge

For the purposes of this analysis it is assumed that the petroleum industry has undergone a basic economic change whereby the degree of competition present in its operation is reduced by the collective control of production brought about by statme-directed proration. Formerly freely competitive in all its parts, the industry is now fully competitive only in its marketing, its manufacturing and transportation, its search for new oil supplies, its drilling operations (with some qualifications), and its capital movements. The practical problem before the industry in its new status is the maintenance of equilibrium, with planned control of crude-oil production (proration) substituted for competition and price as the regulatory mechanism at one point in the supply-demand system. It is further assumed that proration has become so firmly established in the legal and operating framework of the business that it may be looked upon as an institution. The purpose of this paper is to call attention to the effect of unregulated drilling upon the orderly functioning of proration. Economic Structure of Petroleum Industry The economic structure of the petroleum industry, under the current form of proration, may be visualized, in simplified form, as shown in Fig. 1. This diagram is designed to indicate the existing mechanism whereby supply and demand are equated. Demand is created largely by conditions external to the oil business, whereas supply is conditioned by a series of stages incidental to the discovery, development and production of a resource. The time elements involved in changes in demand and supply are of an entirely different order, the demand factor being much more flexible and "quicker" than the supply factors. It should be observed, also, that the position of price, formerly between "demand" and "supply," has been moved to a sidewise location where it still affects demand but influences current supply only through its bearing upon proration, drilling and search. Proration has been substituted for price as a throttle at the well head, but at this point only. The mechanism now works in this fashion: a declining price stimulates demand and the

Jan 1, 1936

By T. S. Fuller

VARIOUS phases of the embrittlement of solid copper containing oxygen by the action of reducing gases at high temperatures through the work of many experimenters are familiar to readers of metallurgical literature. In 1900, Heyn1 recorded observations of copper being heated in hydrogen with the development of fine cracks, the result of the formation of steam within the metal through the action of hydrogen on the copper oxide usually found in copper. Archbutt,2 in 1905, published the results of experiments, showing that all oxygen can be removed from copper by heating to redness, for several hours, in hydrogen. Intercrystalline cracks and extreme brittleness developed. Archbutt attributed the brittleness to the reduction of oxides present in the copper. Bengough and Hill,3 in 1910, encountered the now well-known embrittlement at the outset of their investigation and stated in their paper: It soon became evident that the effect of any heat treatment depended largely on the presence or absence of reducing gases in the atmosphere of the furnace, as well as on its temperature. Hence it became necessary to adopt a somewhat elaborate scheme of heat treatment. The authors found embrittlement in separate experiments due to both hydrogen and carbon monoxide and concluded that: "The gases ruin the alloys after being heated to about 650° C. in their presence."

Jan 2, 1926

By D. L. Pentz

The use of "probability" methods in slope stability analysis has been practised by geotechnical engineers for some time. This paper questions whether the term probability has been properly used since in many cases the term is used in a classical statistical manner only to describe frequency distributions of data. This paper proposes a definition of the term probability which includes the engineers' subjective state of confidence for all critical parameters. Such parameters may include the slope stability model, undetected structural features, strength, groundwater pressure distribution, and geological framework. This process does not make a "better" analysis but it does force the geotechnical engineer to state his opinion in such a manner that others can understand and if necessary, criticize the assumptions. Further, this technique forces the question, "What impact would failure of a slope have on the production schedule or costs of a mine?" The level of risk taken in adopting a particular slope design strategy in a mine is not a question of what Factor of Safety should be selected but, rather, what trade-offs result from steeper slopes and the associated costs of failure. This paper also presents several simple probabilistic techniques which, though widely used in other fields have been all but ignored in geotechnical slope stability analyses. These include the use of stratified sampling to optimize Monte Carlo uncertainty approaches, and the use of simple functional approximations rather than complex stability models in probabilistic analysis. The author presents a case example of this technique and discusses the results in comparison with more traditional methods.

Jan 1, 1983

By W. R. Finney

THE formation of scale in boilers and other industrial equipment, and the corrosion of such equipment, are closely related problems. Since in the petroleum industry these problems cover a very broad field, this paper has been confined to the effects of scale and corrosion on gas engines, compressors, pipes and fittings, used in plants extracting gasoline from natural gas, and the steps taken in arriving at a workable plan for combating these evils at the Midwest Refining Co.'s plants in the Salt Creek field, Wyoming. Eliminating, or at least minimizing, the many deleterious effects occasioned by the use of bad water in jackets and cooling systems of gas engines and compressors has been the subject of much study for many years but no generally accepted plan has been evolved. The problem was unusually difficult at Salt Creek, as the severe winters of Wyoming bring operating conditions quite different from those encountered in warmer states, and the water available was especially bad. While the conditioning of water to prevent scale and to lessen corrosion may not be a particularly difficult problem in plants in large industrial centers, it becomes much more difficult when attempted at plants remote from railroads and by men without previous experience to guide them. In fact this difficulty has been so great in the Wyoming oil fields that until comparatively recently it has been the practice to allow much equipment to be ruined rather than to attempt corrective measures. At the Midwest plants this problem was given attention first by the plant men and later by both plant men and laboratory staff. To the latter it was simply one of many problems which arise in connection with field and plant operations, which must be studied and, if possible, solved. Many mistakes were made during the course of this investigation, but since mistakes, properly interpreted, are of value in guiding one's steps aright, it is believed that a review of the different stages of development which have led up to the present method of handling this problem will prove of interest to the industry.

Jan 12, 1926

By A. R. Matthews

This description of the organization of the Consolidation Coal CO. is intended to include only the portion that is charged with the responsibility of the actual operation of an individual mine, although it has seemed advisable to include several of the all-division personnel, who necessarily come in direct contact with the mine officials. The Consolidation Coal Co. has a staff and line organization and, while most of the contact between these two wings is made between officers ranking above those discussed in this paper, field representatives of several of the staff departments play such an important role in the control of certain phases of activity at the mines that a true picture of the mine organization cannot be had unless these men are included. The demands made upon the producer of large quantities of coal have certainly never been so exacting as they are today. Reductions in the number of accidents and in the cost of individual accidents has passed from the category of a desirable achievement to an unqualified necessity. Although the market price of coal today is lower than it has been in many years, consumers have never been so critical of quality. This market condition is especially severe on the producer to whom one bad shipment may mean the loss of a contract. And the battle to keep the reduction of production costs abreast with constantly dropping prices wages incessantly. For the legitimate producer this situation demands a mine-operating organization that is comprehensive, versatile, efficient and economical; and it is in an attempt to meet these conditions that our present system has been designed. To say that this line-up is incapable of being improved or that it is applicable to all conditions would be to assume a degree of presumption which certainly is not intended here, but our system does meet the conditions which we are called upon to face today with a smoothness and thoroughness which we consider reasonably satisfactory. Authority or Consultation On the chart of Fig. 1 an attempt is made to show as clearly as possible the authority and responsibility of each mine official, together with the

Jan 1, 1931

By Ernest Stütz

(New York Meeting, October, 1918.) THE problem of increasing blast: furnace efficiency through diminution of flue-dust production while operating with burdens consisting largely of fine ores has of recent years attracted the attention of metallurgists, whether directly or indirectly interested in the economies of iron smelting, and the various methods evolved from theory or practice have been submitted to wide discussion. After the very thorough and, at that time, exhaustive view of the whole subject, which was afforded to the industry by the meeting of this Institute in February, 1912, the subject was again taken up at the meeting of the Verein deutscher Eisenhüttenleute at Diisseldorf in December, 1912. While American and German conditions are not entirely identical, it may be of interest to give here the words of the gentleman summing up the discussion at the Diisseldorf meeting: ' The chief advantage offered by the use of briquettes lies in the fact that disturbances in the furnace, caused mostly by the presence of fine ores in the burden, are avoided, and that blast pressure can be considerably reduced. The resulting economies cannot be overrated, as, with lower blast consumption per ton of product, the installation will be able to take care of increased production. In consequence of lower pressure and speed of blast, heat is more efficiently utilized, flue gas temperature is lowered, and coke particles are less liable to be carried along with the flue dust, of which considerably less is produced. Finally, by increased regularity of operation and higher . temperature in the lower parts of the furnace, the quality of the product is improved. The question of briquetting iron ores has grown to be one of the most important in the iron industry, and, it is not any more a question of what is the cost of briquetting ton of ore, but what, in using ore briquettes, is the cost of production of a ton of iron.'

Jan 7, 1913

By J. E. Burke

THE origin of so-called annealing or recrystalli-zation twins in face-centered-cubic metals continues to be a matter for speculation, and in the present report an attempt is made to explain their origin and to account for at least a majority of the observations concerning their behavior. The fact that annealing twins are prominent only The speelmen was deformed 8 pet in compression and then indented over the lower left-hand corner in a Rockwell in-denter, and then annealed to cause partial recrystallization. Note intense twinning in heavily deformed part and slight twinning in less deformed part. The upper right-hand corner is unrecrystalized. Area reduced approximately 25 pot for reproduction. after recrystallization suggests that deformation may be necessary for their formation. In 1926, Mathewson1 reported the observation by Phillips that annealing twins are frequently parallel to strain markings which delineate octahedral planes in the deformed (and partially recrystallized) matrix, and suggested that strain markings are mechanical twins which grow into annealing twins during recrystallization. Later work by Burke and Barrett' has shown that strain markings are traces of planes upon which slip has occurred, and that there is no evidence for the formation of mechanical twins of microscopically resolvable width in face-centered-cubic metals. Mathewson3 has pointed out, however, that slip may produce twin faults, and later modifications of this hypothesis have assumed that twin faults rather than true mechanical twins serve as the nuclei for annealing twins. Carpenter and Tamura5 suggested, also in 1926, that annealing twins might form by accidents of growth. A close-packed layer of atoms can be added to the octahedral plane of a face-centered-cubic metal in two possible positions, the right position

Jan 1, 1951

By Charles Bohdanowicz

Production of crude in 1937 decreased (Tables 1 and 5) by about 2 per cent, while gas production for that period increased by about 6 per cent after a slight decrease in 1936 (0.4 per cent).' As in preceding years, drilling operations were confined principally to extensions of old oil fields in the Jaslo district (fields 1 and 7) and to some extent to such extensions in the Stanislawbw district (field 27). Deepening of old wells to horizons reached more recently by new wells gave on the average better results per well than those attained by new wells (Table 3). Reserves of proved lands have increased some by new oil fields discovered, Targowiska (field 8) and Czarna (field 19) both of which, however, have only small production. The Daszawa gas field (field 25) has not been extended, but two new gas fields were located instead— Opary, distant 25 km. (151/2 miles) northwest of Daszawa, Balicze at 12 km. (7 1/4 miles) southeast of Daszawa, and Kalusz (TESP Company exploiting potassium salts) in the vicinity of the town of that name (field 33). Drilling upon the gas area near Tarnbw and Debica, while gas-bearing sandstone had been found at depths of from 300 to 512 meters (984 to 1680 ft.) (Zdziary No. 2) and at 220 m. (722 ft.) [pressure 11 atmospheres, flow 24 cu. m. per min. (847 cu. ft.)] (Przyborbw No. l), has not as yet ascertained horizons qualified for permanent exploitation. The exploring well near Kos6w remained for the last seven months at the depth of 1420 m. because of the collapse of rotary drilling pipe. Below the 300-m. level no gas sands have been encountered at this well. Gas Reserves In connection with the broad plan of developing industrially the sector of Poland lying between the Vistula and the San Rivers, and extending farther north as far as the city of Radom, there arose the necessity of a more accurate calculation of gas reserves for the fields of

Jan 1, 1938

By J. M. Glass, C. D. Sholtess

We at Hughes Tool Co. are extremely proud of the quality of the hardware and techniques introduced through our efforts in tunnel-machine development and of the ready acceptance of them by manufacturers and contractors throughout the world. All of us who attended the conference and who are represented in the book, we believe, anticipate an increasing need for improved methods of underground excavation. The development of such methods will permit the further exploitation of our underground resources plus providing underground space for transportation and habitation at a rate compatible with demand. We hope that our comments, derived from the application of Hughes Tool Co.'s rotary boring experience, may provide a better understanding of the boring method as a possible avenue through which the desired improvement in underground excavation may be attained. We hope you may also become aware of some of the problems Hughes, as a pioneer developer of raise, shaft, and tunnel-boring equipment, must face prior to further major undertakings in this very interesting field. Our task is to acquaint you with the present status of the Hughes Tool Co. development program as it relates specifically to tunnel-boring machines. We feel this task can best be accomplished by a brief review of the general sequence of events leading to and constituting an equipment development program and more specifically the manner in which these events have occurred to either influence or further our boring-machine development program. The development of a machine to accomplish a certain function or series of functions is usually a very long and tedious process to which any number of individuals must contribute, perhaps over a period of centuries. Of particular irony is the fact that often those who contribute most generously do not necessarily reap the greatest immediate benefit. A marketable ma- chine will, however, result from a sequence of events such as these: 1) A problem or need is defined. 2) An idea is born to eliminate the problem.

Jan 1, 1970

By Arthur L. Flagg

The Elk City mining district of Idaho occupies a position near the geographical center of Idaho county, a region of moderate elevation in the western foot-hills of the Bitter Root mountains. The district comprises an area of approximately 350 Sq. miles, bounded on the west by the Newsome district and on the south by the Dixie and Oro Grande districts. There are no mining districts to the north or east. Elk City, the principal town and the seat of the mining office for the district, is situated in a hydrographical basin surrounded by low hills. The elevation is 4,200 ft. above sea-level. Through this basin flow Elk Creek, Red river, and American river, which unite west of town to form the south fork of the Clearwater. The one township is set out from the Bitter Root Forest Reserve. Though a railroad starting from the Stites terminus of the Clearwater Short Line of the Northern Pacific railroad has been under consideration for some years, the camp is yet without railroad facilities. The projected road would follow the south fork of the Clearwater on easy grades, but would be very expensive to build and maintain. While such a road would greatly benefit those who are now operating in the camp, and in a sligh degree stimulate interest in its possibilities, there is hardly business enough to warrant its construction. At present all supplies and equipment are hauled in by wagon from Stites, a distance of 58 miles, over a wagon road constructed by the State in 1904, following in the main the old Nez Perce trail. While this is not a bad road, it is not all that might be desired. Starting at Stites at an elevation of 1,327 feet above sea-level, the road runs through low hills to Clearwater, a distance of 10 miles. In the next 16 miles the climb is steady until the Mountain House is reached, which is near the summit of Mount Pisgah. This is the highest point passed on the road, having an elevation of 6,500 ft. From the

Jan 1, 1914

By J. F. Sepulveda, J. D. Miller

Tar sand deposits in the state of Utah contain more than 25 billion bbl of in-place bitumen. Although 30 times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion bbl). Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water separation process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique. Experimental results with an Asphalt Ridge, Utah, tar sand sample indicated that percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage. These variables were identified by means of an experimental factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence gathered in this investigation seems to indicate that a hot-water separation process for Utah tar sands would allow for the efficient utilization of this important energy resource.

Jan 9, 1978

By E. P. Pfleide, L. W. Gibbs. J. R. Gross

A method using computer techniques is described for the comparative evaluation of truck performance over any given haul road using readily obtainable manufacturers' data. An additional computer program is utilized to calculate individual cycle times for each truck and shovel combination, fleet requirements for any desired production rate, and to estimate comparative costs. The introduction of a large number of variables into the program permits management to determine the critical system factors having the greatest bearing on costs. Thus, the method described can be used not only for analysis of needs for a new surface mine but for cost improvement in existing mines where changes in truck and shovel operations are contemplated. The systems analysis approach to the solution of problems in the mining industry is gaining in industry acceptance. This is a logical development in view of the fact that a mine constitutes one of the most dynamic systems of production. In contrast with a manufacturing plant, situated in a location selected through choice and utilizing a regulated source of quality controlled raw materials, the miner must go where the ore is and he is faced with ever changing physical conditions. He is subjected to the vagaries of nature, and he can never mine the same ore twice. What is systems engineering? There seems to be no concise and universally accepted definition of the term and its meaning is still fairly local. It deals largely with trade-offs of subsystem characteristics to achieve some desired result in an overall system. This concept of suboptimization can be explained by an example. If the objective of a mining company is to produce a certain quality ore at minimum cost, the optimum operation is not achieved by minimizing all costs, since all phases of mining are interrelated. Reduction of blasting costs might well increase loading, hauling, and crushing costs out of proportion to the resulting saving in explosives. Hence tradeoffs are necessary. It is evident then that an optimum system is achieved through a blending of suboptimal components which taken together yield the desired result. OBJECTIVE For our mathematical model we will assume the existence of a hypothetical new organization called Taconite Mining Co. (TMC). TMC has made an analysis of their orebody, their proposed operation, and

Jan 1, 1968