Search Documents

By V. F. Marsters

SEEPAGES Of oil in Ecuador have been known for many years. The locality first to receive attention, and still worked in a modest way, lies on the north shore of the Santa Elena peninsula, between La Puntilla and Salinas. Operations were first conducted largely by local capital. Later, foreign companies acquired large blocks of land, where they have done considerable drilling. For details concerning present drilling activities in Ecuador, we are indebted to Leon Price, an American resident engineer of Ecuador. The information solicited, came to the author through the office of the American Consulate,' with permission to use it. The coastal plain bordering the Province of Tumbes, Peru, continues to the northeast, but narrows on passing the Zarumilla River. From this, point northward it widens toward Santa Rosa. In fact, the pampas, as shown on the official Wolf map, correspond fairly well to the areal extent of the coastal plain as far as Guayaquil. This is shown in a general way on the accompanying map. The author understands that the Guayaquil embayment is bordered on all sides by the coastal plain, as recognized at Tumbes and farther southwest, and that it can be followed without a break as far north as Palmar. This view is supported by the mapped area regarded by Mr. Price as favorable or possible oil territory. Moreover the islands in the Gulf of Guayaquil are the same geologically as the coastal edge, being composed of Tertiary sediments. The author understands also that Tertiary formations occur north of Palmar. According to a report by Mr. Cardon, of Guayaquil, Tertiary sediments are exposed in the region of San Francisco and extend to and beyond Pta. Calera. There is also reason to believe that at least the lower part of the valley of the Santiago River is occupied by Tertiary sediments, which probably border the coast line and extend into the River Mira basin, and into Colombia.

Jan 7, 1922

By M. R. J. Wyllie, Michael A. Torcaso

With the continued deep drilling of today, increasing numbers of high pressure and high temperature gas-condensate reservoirs are being discovered. Correspondingly, the ranges of properties of gas-condensate reservoir fluids are also being increased. The literature1*'." contains several excellent reviews of the property ranges in presently known condensate reservoirs. When one examines these property ranges, it becomes apparent that the need for reliable data is great if the engineer is to evaluate properly or appraise a gas-condensate reservoir. It is the purpose of this paper to present phase-behavior data that will point out some of the important variables that influence recovery from gas-condensate reservoirs produced by pressure depletion. All these variables may be resolved into two major categories: the hydroc:arbon composition of the reservoir fluid and the physical properties of the reservoir. But the variables which we will consider are those which are usually determined from well tests shortly after discovery and are, consequently, readily available to the engineer. They are as follows: (1) the producing separator gas-stock-tank liquid ratio, (2) stock-tank liquid gravity, and (3) reservoir temperature. Laboratory depletion studies have been performed on several reservoir fluids to illustrate the effect of changes in the cronsidered variables upon ultimate recoveries. The deviation factors, Z, of a series of reservoir fluids were determined experimentally to illustrate their order of magnitude and their effect upon the calculation of in-place reserves existing at high pressurcs and temperatures. The procedures followed in conjunction with the performance of these studies and their associated calculations are illustrated in Fig. 1. For the purpose of this paper, the depletion recoveries are expressed only in terms of pcr cent of initial stock-tank liquid, with the abandonment pressure assumed to be 500 psig. VARIATION OF RECOVERY WITH INITIAL PRODUCING SEPARATOR GAS-STOCK-TANK LIQUID RATIO The producing separator gas-stock-tank liquid ratio has long been one of the principal criteria in assumptions and generalized correlations' used for the estimation of ultimate recovery from gas-condensate reservoirs. Fig. 2 presents a plot of the cumulative recovery of stock-tank liquid at abandonment as a function of the initial producing separator gas-stock-tank liquid ratio. The graphical illustration represents the results of 44 laboratory depletion studies performed on actual gas-condensate fluids. These data are presented not only to illustrate the general trend of ultimate recovery increase with initial producing ratio increase but to emphasize the considerable variation in possible recovery at any given producing ratio. Table 1 presents the properties of two actual reservoir fluids chosen to illustrate the approximate extremities of producing ratios for gas-condensate systems. The fluids designated as A and B exhibited initial producing ratios of 3,400 and 114,000 scf/bbl, respectively. Fig. 3 presents a graphical comparison of the cumulative stock-tank liquid recoveries, calculated from the well-stream compositions and produced volumes for each fluid during depletion. It is to be noted that Fluid A exhibited a recovery of only 16.5 per cent when produced to an assumed abandonment pressure of 500 psig while the corresponding recovery for Fluid B was calculated to be 62.2 per cent. This difference in recovery, which exemplifies the general trend of recovery increase with initial producing ratio increase, is readily explained by consid-

By L. D. Anderson

IN STUDYING Utah as a lead producing state one is immediately confronted by the fact that few, if any, of the ores of the state are valued for their lead contents alone. More correctly the ores from which this metal is recovered are characterized as silver lead. Even then the whole story is not told for many of these ores carry also gold, copper, zinc, bismuth, antimony, arsenic, tellurium, and other metals. It becomes apparent, therefore, that the production of lead i11 Utah is influenced by many factors. For example, i11 the early part of 1923 there was a marked increase in the production of the lead by reason of the efforts made by silver mines to produce as much silver as possible before the termination of purchases under the Pittinan Act in June, 1923. As nearly all silver ores carried more or less lead the production of that metal was increased with the increase in silver production. Very few, if any, ores of the State are mined for their lead contents alone. Important as Utah's contribution to the lead output of the country is nevertheless it is bound up to some extent with the production of gold, silver and copper.

Jan 1, 1925

By R. A. Meussner, C. T. Fujii

Chromium solution in wustite depresses the oxygen activity in a nonideal manner and expands the lattice slightly. Gravimetric measurements of the equilibrium compositions of wustite containing 0.00 to 1.38 wt pct Cr define the oxygen potential (CO2-CO atm) and the limits of the phase field at 1000°C. These data extrapolate to a maximum solubility of 2 wt pct Cr. The lattice parameter data, room-temperature measurements of quenched samples, differ significantly from those in the literature. Both pure and chromium wus-tites contract at uniform and equal rates as the oxygen content (metal deficit) increases. The a. US metal deficit relationships are straight lines showing none of the curvature previously reported. At constant metal deficit, the a. expands by 0.002? on alloying with 0.4 to 0.5 wt pct Cr but is insensitive to further chromium additions: a small expansion rather than a marked contraction. These results require a modification of the accepted alloying mechanism. IN the high-temperature oxidation of Fe-Cr alloys in Ha-H,and CO2-CO atmospheres the vapor transfer of oxygen from the continuous wustite outer scale to the porous inner scale/alloy interface sustains the high oxidation rates.1"3 The driving force for this transport is the difference in the oxygen activity of the outer wustite and that at the inner scale/alloy interface. In pure CO2, as well as in CO2-CO atmospheres, carburization of the alloy accompanies this oxidation. Current efforts to evaluate the parameters controlling this carburization have shown that the process is not simple; i.e., the carbon concentration in the alloy initially increases rapidly, reaches a maximum, and then decreases slowly as the oxidation time is extended. This is the same pattern reported by McCoy for the more complex oxidation-carburization of stainless steels and an Fe-Cr alloy in CO2 at lower temperatures.4 These changes in the carburization process occur while the overall oxidation rate and the lattice parameters of the scale layers remain constant. If this invariance of the lattice parameter is assumed to indicate a constant scale composition and thus a constant oxygen potential, the carburization results are not easily explained. Electron microprobe traces across the thickness of these outer scales, however, have revealed distinct chromium gradients penetrating 10 to 50 µ from the inner surface where the chromium concentrations were estimated at a few tenths percent. The variation of the chromium cmcentration on the inner surface of the scale, and the resulting change of the oxygen activity, during the oxidation process is considered to be important in defining the carburization process. Thus, to gain an understanding of the complex oxidation-carburization proc- ess, it was necessary to measure the properties of wustite containing known amounts of chromium (chromium wustite). Although the general features of the Fe-Cr-0 equilibrium diagram between 900° and 1300°C have been fairly well established by Richards and white: Wood-house and White,6 Seybolt,7 and Katsura and Muan,8 there have been no detailed studies of the limits of the chromium wustite phase field or the properties of these alloyed wustites. The recent results of a limited study of chromium wustite by Levin and wagner9 indicate that more than 0.67 wt pct Cr is soluble in wustite above 850°C and that this alloying is accompanied by a substantial lattice contraction. This change in the lattice parameter was not evident in the X-ray diffraction patterns of wustite layers from the oxidation experiments;1,3 the lines were sharp even though a chromium gradient existed in the scale. The present paper describes gravimetric equilibrium experiments which delineate the boundaries of the chromium wustite single-phase field at 1000°C and define the changes in the oxygen activity and the lattice parameter of wustite as functions of chromium and oxygen contents. The lattice parameter data of chromium wustite obtained from these equilibrium and special quenching experiments differ considerably from those reported.9 Those for pure wustite show significant differences from the widely accepted data of Jette and Foote.10 Since the causes of these differences are not easily assignable, and since the literature contains many sets of data on wustite which if not in conflict are at best not in harmony, the experimental procedures are discussed in the present paper. EXPERIMENTAL Oxide Preparation. The specimens used in these studies were porous pellets compacted from high-purity (Fe,Cr)2O3 or Fe2O3 powders. These powders were prepared from electrolytic chromium (99.8 pct purity) and electrolytic iron purified by consumable-electrode, vacuum arc-melting processing (299.9 pct purity).11 The oxides were produced by standard analytical procedures: solution of the metals in acids (HC1, then HNO3 added), coprecipitation of the hydroxides (NHaOH), and filtering and washing these precipitates. Initial dehydration of the coprecipitated hydroxides was done in a porcelain evaporating dish heated by a Meker-type burner, final dehydration by firing in a recrystallized alumina crucible at 1000" to 1050°C for 20 hr in an electrically heated furnace. Spectrographic analysis detected the following impurities: silicon, 0.01 pct or less; aluminum, 0.001 pct to trace; manganese and copper, 0.0001 pct to none. Each of these levels is at least one order of magnitude lower than in commercially available CP grade ferric and chromic oxides. Fluorescence analy-

Jan 1, 1969

By J. E. Sherborne, P. H. Jones, E. C. Babson

A study of the Chapman zone in the Richfield field, Orange County, California, indicates that the quantity of oil recovered by present methods will be only a small portion of the oil originally in place. Since the volume of residual oil is believed to be of large magnitude, an experimental water-flooding operation has been initiated in order to determine whether water-flooding offers promise as an economical method of recovering some of this residual oil. A single injection well was drilled between old producing wells, and a water-treating plant using alum flocculation and chlorination was designed and built. Water has been injected into the input well for six months at rates in excess of 100 bbl. per day. Production from one of the neighboring wells has increased materially, the oil production having risen from 7 to 30 bbl. and the water From I to 40 bbl. per day. While definite conclusions regarding the economic success of water-flooding in the Chapman zone are not justified at this time, it has been demonstrated that water can be injected into the zone on a sustained basis and that this water will displace appreciable quantities of oil from the sand. Introduction As a result of an investigation of subsurface conditions in the Chapman zone of the Richfield field, it was concluded that ultimate oil recovery from this zone would probably be low and that natural water encroachment was so localized as to be of little importance from a recovery stand- point. Furthermore, it was found that in many portions of the zone the wells were approaching an unprofitable level of production. When these data were presented to the management of the Union Oil Co.; their reaction was that an attempt should be made to develop methods of recovering at least a portion of the large quantity of oil remaining in this zone. After some investigation, it was decided that wafer-flooding offered the most likely means of accomplishing this end, but reservoir conditions in the Chapman zone differ so widely from those encountered in any of the flooding projects described in the literature that it was difficult to evaluate the probability of success. Despite encouraging results from laboratory tests, it was not even certain that water would displace an appreciable volume of oil from the Chapman sand under reservoir conditions. Therefore, it was decided to initiate a small-scale project, for two purposes: first, to determine whether water would displace oil from the Chapmall sand and, second, to obtain information and experience for future operations if water-flooding appeared to be a promising method of secondary recovery. Reservoir Data The Chapman zone is the upper of the two producing zones in the Richfield field, being found at depths from 3000 to 3700 fi.. The productive portion of the zolle consists of a large irregularly shaped sand body, which is more than 400 ft. thick at the top of the structure. As the margin of the field is approached, the sand is replaced

Jan 1, 1945

By AIME AIME

TWO technical sessions, an excursion through the Midwest refinery and a smoker, marked the first day of the meeting of the Petroleum Division at Casper, Wyo., on Aug. 28. Ninety-nine members and guests registered and there was an excellent attendance at 'all functions. The -local committee under the general chairmanship of J. C. Lindsay, general manager of the Western Pipe Line Co., had made every possible arrangement for the convenience and comfort of the visiting members and the Program Committee under E. L. Estabrook, vice-chairman of the Petroleum Division, had brought together a most interesting series of technical, papers. The meeting centered mainly on the various features of the Salt Creek field but there were also contributions from the technology of production in California, the Mid-Continent, and the Texas fields. The opening session was called to order by Mr. Estabrook at the Townsend Hotel on Friday morning. The members and visitors were welcomed appropriately by Ex-Governor B. B. Brooks, president of the "Rocky Mountain Oil and Gas Association, who recalled the changes that had taken place as Casper, a frontier cow town, became a thriving oil metropolis. F. Julius Fobs, chairman 'of the Petroleum Division, responded and then took the chair. He introduced H. Foster Bain, Secretary of the Institute, who expressed the regret of those members members who found it impossible to stop over en route to Salt Lake City and his own pleasure at meeting with the Division in the field. Following these introductory ceremonies the technical session began with a "Sketch of the Geological Formations of Central Wyoming," presented by J. G. Bartram of the Midwest staff. It was brief and to the point and contributed greatly to the easy under¬standing of the succeeding papers by those unfamiliar with the region. The talk was illustrated by a large scale columnar section -and a copy of the excellent, geological map of the State recently issued by the U. S. Geological Survey.

Jan 1, 1925

By AIME AIME

AN unusual interest in the question of orienting the young college man in the mineral industry was shown in a well-attended session* of the Engineering Education Committee on Monday afternoon. About seventy-five employers and educators of mining engineers were present and took part in the discussions.

Jan 1, 1929

Jan 1, 1884

By Cresap P. Watson

ABOUT the time this magazine reaches its readers, Cresap P. Watson will celebrate his 53d birthday. If he spends that birthday at his West Los Angeles home, he won't be far, as distance is measured today, from Santa Barbara, where he was born on July 8, 1895. He is truly a member of a petroleum family; one brother, N. O. Watson, managed Royal Dutch Shell interests in Venezuela for years and is now general manager of the Caribbean Petroleum Co. at. Maracaibo; another brother, Rex, is vice-president of the Drilling and Exploration Co., while brother-in-law Ben Belt is an executive of Gulf Oil. His own life has centered in the petroleum industry since his first job in 1913 as camp cashier for a Mexican oil field at Tampico. Down on the isthmus of Tehuantepec he advanced to tool dresser and' production foreman for the company. The first World War interrupted his Mexican experience by transforming him into an artillery officer in France. Once the Army ceased to demand his services¬by then it was 1919-he returned to the task of furthering his professional career as agent for the Amerada Petroleum Corp. By 1927 he had reached the position in which he could be called an executive in the petroleum industry, having organized and become president of the Federal Royalties Co. His activities in local and national legislation affecting the petroleum industry increased as has his advocacy of the development of oil and gas fields under sound engineering and conservation principles through unitization or other co-operative forms of operation. Considerable amounts of his time go to the promotion of industry public relations.

Jan 1, 1948

By Clint L. Milliken

The smelter is often considered the flywheel of the copper industry. No other unit can produce such a uniform product from so many starting materials. Direct-smelting ore, concentrate, precipitate, refinery slag, and scrap in almost any combination can be processed into blister or anode copper. Copper smelting practice has advanced little in the last century. It is still basically matte smelting, although the source of matte has changed from the blast furnace to the reverberatory furnace because of changes in smelter feed, and the Great Falls converter has been replaced by the Peirce-Smith converter. This lack of progress has continued because the economic forces required to produce change have not been of sufficient magnitude. Traditionally, the smelting, operation has required only about 10% of the total cost of producing copper from its ores and this minor cost item has not warranted change until recently.

Jan 1, 1971

By L. W. Pommier, F. B. Brien, A. K. Bhasin

In the field of mineral processing, although many operations are applied to suspensions of ore particles in fluids, there is a lack of fundamental knowledge relative to the flow resistance encountered by immersed bodies moving through solid-liquid suspensions. Previously proposed equations, based on the Ostwald-de Waele (power-law) model for non-Newtonian fluids, are exam ined in the turbulent flow region relative to a number of pertinent variables and their effects on the movement of immersed bodies. As more knowledge is acquired in regard to the effects of suspension variables on the rheological properties, useful relationships may be proposed to allow predictions of conditions to achieve optimum results for engineering purposes. In the field of minerals processing, many operations are applied to suspensions of ore particles in fluids. The differential movement of solids of various sizes and densities in suspensions is of utmost importance to gravity concentration, wet classification, flotation, hydrometallurgy, and pipeline transport of solids. The subject is also of importance to other branches of engineering; for example, those involved with soil mechanics, ceramic slips, and oil-well drilling fluids. There is a lack of fundamental knowledge relative to the flow resistance encountered by immersed bodies moving through solid-liquid suspensions. The problems encountered in the direct application of the well-known Stokes and Newton's Laws to non-Newtonian systems have been examined in a previous paper.' Equations were proposed based on the Ostwald-de Waele (power-law) model for non-Newtonian fluids. This present paper examines these equations in the turbulent flow region relative to a number of pertinent variables and their effects on the movement of immersed bodies. It is thought that, as more knowledge is acquired as to the effects of suspension variables on the rheological properties, useful relationships may be proposed to allow prediction of conditions to achieve optimum results for engineering purposes. The purpose of this paper is to make an initial assessment of the nature and magnitude of pertinent suspension variables. In order to avoid too voluminous a document, the examination of kinetics and mechanisms will be omitted at this time. THEORY A Newtonian fluid is defined as a fluid in which the stress is proportional to the rate of strain, 2 i.e.: H = viscosity; see Table I. for list of symbols The following equations are conventionally used to assess the motion of spherical particles moving under laminar and turbulent flow conditions through Newtonian fluids: When these relationships are applied in practice to suspensions, the liquid density is substituted by a composite suspension density, and viscosity is usually taken as that of the suspending liquid or an approximated "apparent viscosity." However, suspensions are non-Newtonian in character3 and thus, more than one viscosity parameter is required to describe their behavior. A number of models have been proposed for non-Newtonian fluids;2,4 among these the simplest is the Ostwaldde Waele or power-law model for incompressible fluids which for one dimensional flow may be reduced to:

Jan 1, 1970

By R. F. Mehl, C. S. Barrett, A. H. Geisler

THE mechanism by which the super-saturated solid solution of 20 per cent silver in aluminum decomposes has been reported in two previous publications. 1,2 The analysis of streaks in Laue photograms showed that thin platelike particles (the so-called Guinier-Preston aggregates) form upon {111} matrix planes in the early state of decomposition.1 The size of these particles is larger, the higher the temperature at which they form in accordance with nucleation theory;3 at all temperatures they increase in size with aging.2 When they have grown thick enough to afford three-dimensional diffraction, powder X-ray photograms show that the structure is not that of the equilibrium precipitate y but that of a transition lattice ?'. Since this is also platelike in shape and also lies upon the {111} matrix planes with the {110} direction in the matrix parallel to the {11.0} direction in ?', it seems likely that the original platelet particles are merely ?' in an early stage of formation, and thus finely dispersed. The atomic spacing and pattern on the {00.0} plane in ?' are identical with those on the {111} matrix plane to which it lies parallel, and since comparable directions in the two planes are parallel, the lattices are thus coherent at the interface; an analogous coherence has been found in aluminum-copper alloys.3 The structures ?' and y are both close-packed hexagonal and are oriented alike; they differ only in interatomic distances. Consequently, ? ' is regarded as y strained from its ordinary dimensions by the lattice coherency between it and the matrix.2 The lattice movements that transform the matrix to the equilibrium precipitate appear to be very simple.2 The mechanism of precipitation in this system is simpler and is more precisely known than that in any other system,2,4 hence the system should be a profitable one for the difficult task of correlating property changes with structural alterations. The present report provides additional studies on powder X-ray diffraction from alloys of 10 per cent, 20 per cent and 30 per cent Ag, and presents the correlation of crystallographic changes with changes in microstructure, Brinell hardness and electrical resistivity of the three alloys. PREPARATION OF SAMPLES AND EXPERIMENTAL PROCEDURE The preparation of the 20.2 per cent Ag alloy has been described.2 Alloys containing 9.9 and 29.7 per cent Ag were prepared from 99.97 per cent Al and 99.99+ per cent Ag using a similar procedure. Rolled

Jan 1, 1943

By NORMA D. MACFADDEN

WHILE the library work of the Woman's Auxiliary to the A. I. M. E. was founded three years after the formation of the Auxiliary, its present policy of establishing permanent libraries in mining camps throughout the United States dates only from 1924. Since then sixteen libraries have been established and thousands of books have found their way to homes of far-away miners, bringing pleasure and knowledge to a multitude of Americans and future citizens. Library work was initiated under the presidency of Mrs. H. W. Hardinge in 1922 and firmly established with her aid as one of the main activities of the Auxiliary. The first chairman served but a short time and Mrs. A. O. Ihlseng then took over the work of chairman of the Library Committee. To place the surplus books of Auxiliary members and their friends in use in mining camps was the immediate work of the committee. This was accomplished by placing a traveling library in the Bureau of Mines' cars and also by sending books for distribution to section chair- men in our larger mining camps.

Jan 1, 1929

"WELFARE…Welfare endeavor in connection with both the metal and the coal mines of Utah has shown gratifying progress during recent years and both the operators and their employees are deserving of much credit for the efforts put forth to better living, working, educational and receational conditions in most of the mining camps of the state.In the older metal mining camps of Utah, where the towns are incorporated and independent of the mining properties operating in the vicinity, less opportunity is pre¬sented for the companies to exercise efforts looking towards improved welfare conditions than is the case of camps located on company ground and under the full control of operators.Even in such camps, however, as illustrated in Bingham, the companies can do much to better welfare conditions. In this camp the Utah Copper Company has spent $800,000 since 1 920 in the erection of modern brick cottages, apartment houses and the Gemmell Memorial Club. The cottages and apartments have every convenience to be found in up-to-date city homes. The Gemmell Memorial Club, erected and equipped at a cost of $1 75,000, was provided by the company for the benefit of the Utah Copper Company employees living in the canyon and has been made the recreational center for the camp."

Jan 1, 1925

The mining companies on the page opposite are among the elite industrial 500 in Fortune magazine's June Directory of U. S. firms that rang up the largest dollar sales volume in 1967. The companies are listed according to their 1967 sales rank, which is given along with their 1966 rank for comparison. Mergers played an important role in the addition and deletion of several companies to the list. Tenneco, Occidental Petroleum and Gulf & Western Industries made the list of mining companies by their purchases of Kern County Land, Island Creek Coal, and New Jersey Zinc, respectively. In turn, these three companies disappeared from the list. General Aniline & Film acquired Ruberoid, and Ideal Cement is now a part of Ideal Basic Industries -a name change only. Only two companies, St. Joseph Lead and U.S. Smelting, Refining & Mining, were actually displaced from the list. The mining industry increased its sales 14.5%, placing fourth among the 22 industrial classifications listed in the Directory. However, among the ten biggest losers in sales were four mining companies-Kennecott Copper, -33.8% ; Asarco, -21.8% ; Amax, -16.5%; and Anaconda, -15.1%.-which was mostly a result of the copper strike, except for Amax which suffered strikes at its molybdenum and aluminum operations. Mining heads the list of industries for return on sales and assets per employee, while it rests at the bottom with respect to sales per dollar of invested capital.

Jan 8, 1968

By M. Cross

INTRODUCTION The results of the Japanese dissective investigations have [l-4] transformed our understanding of how the blast furnace operates. These studies revealed an internal structure of the furnace burden with five main zones, as illustrated in Figure 1. In the granular zone the charged material retains its structure whereas in the cohesive zone the iron ore particles are at advanced stages of reduction and form a semi-molten mass with a relatively high flow resistance. In the active coke zone molten iron and slag flow through a matrix of loosely packed coke. The raceway is a relatively small void space generated by displacement of coke due to the hot blast momentum, whilst the hearth is packed with coke, slag and molten iron. [ ] It is now well appreciated that furnace control is largely achieved and maintained by using the burden charge distribution to determine the gas glow distribution within the furnace and, hence, the shape and extent of the cohesive zone. In fact, Wakayama et a1 [5] of Nippon Steel Corporation state that optimum furnace operation is synonomous with the formation of a desirable cohesive zone shape, which in turn is almost solely determined by the burden charge distribution and its mechanical properties [6]. Much of the development work on operating furnaces since the dissective investigations has been oriented towards the identification of external furnace measures which reliably predict the shape of the cohesive zone. Currently the most popular measures are top gas temperature, velocity and CO/CO, ratio profiles [5]. More recently pressure distributions as evaluated from a series of wall measurements down the height of the furnace are also being utilised [7] to identify the position and shape of the cohesive zone. A great deal of emphasis has been placed upon achieving a consistent quality in the burden charge materials, establishing a suitable set of operating conditions and only making changes when forced to, ie., the operation for some reason moves outside a desired operating range or the production requirements change. Operational control schemes based upon this philosophy (eg., Kawasaki's GO-STOP system [8]) have been remarkably successful at achieving both high production rates and relatively low fuel costs. Mathematical models have long been used as tools to assist in the analysis of the blast furnace process. Although, the models have been useful in post-operative analysis and for identifying trends, etc., they have not proved reliable for detailed design criteria or as the basis for effective control schemes. Such mathematical models have moved from simple statistical correlation, through overall and stagewise heat-and-mass balance calcu-

Jan 1, 1984

By B. S. Butler

The principal ore deposits of Arizona are in the southern, cen-tral, and western portions of the state, which physiographically are part of the Basin and Range province, southwest of the Colo-rado Plateau (Pl. I). The Basin and Range province is characterized by numerous subparallel mountain ranges separated by plains or valleys. Most of these ranges trend northwest to north, parallel to the margin of the Colorado Plateau; but in southeastern Arizona, southern New Mexico, and northeastern Sonora, they trend northward, transverse too the edge of the Plateau. The mountains rise abruptly from plains or valleys, the margins of which in many places are pediments cut on hard rock. Some of the plains form closed basins (bolsons, playas), but most of them are drained. The Basin and Range province in Arizona is divisible into the Mountain Region and the Desert Region4 (Pls. I and II). The Mountain Region forms a belt 60 to 100 miles wide that contains most of the large ore deposits. Its longest range measures about 55 miles, the widest 20 miles, and the highest peak more than 10,000 feet above sea level or 7,000 feet above adjacent valleys or plains. Broad plain-forming valleys are exceptional, but several with maximum widths of 20 to more than 30 miles appear in the southeastern portion. In the Desert Region the mountains are relatively low, narrow, serrated, and steep, with sharply angular profiles. There are a few exceptionally large ranges of which the longest measures nearly 100 miles and the widest 18 miles. The highest peak is some 7,000 feet above sea level, and the maximum local relief amounts to about 5,400 feet. Broad and comparatively low desert plains form 50 to 75 per cent of the area.

Jan 1, 1939

By C. E. Arnold

THE CHAIRMAN (PERCY G. BECKETT, Globe, Ariz.).-When you are at Miami tomorrow, you will see a very interesting comparison on the surface of the two mining methods that are being employed there largely. In the case of the surface over the Inspiration mining method, you won't see very much left of the surface. Everything has gone down. In the case right at the line of the Inspiration ground and the Miami, you will see that the surface over the top slicing which the Miami company has been doing in that country has been riding down evenly and uniformly; and it gives a very marked comparison of the two types of mining, and, to a certain extent, of the different degrees of waste dilution. I would ilke to hear from Mr. Maclennan on this subject. F. W. MACLENNAN, Miami, Ariz.-A paper based on percentage extraction by shrinkage stoping is a difficult one to discuss for the reason that it is hard to arrive at extraction figures until a section has been completely mined out. In the Miami mine we are using a method of shrinkage stoping with narrow stopes and pillars. This ore has been completely broken up and we have started in at the far end to draw off the ore mass maintaining the top of the broken ore dipping at an angle of 60° away from the direction in which we are retreating. A very important point I think about drawing a large. mass of ore down at an angle rather than trying to maintain the top of the ore more or less horizontal is that drawing at a steep angle has a tendency to create a horizontal movement in the ore mass as well as the vertical movement of the ore traveling down to the drawing off chutes. We know that this takes place, on account of the horizontal movement of marked

Jan 12, 1916

By Linney, Robert J.

REPUBLIC Steel Corporation's iron-ore properties in the Adirondacks consist of mines, mills, and sintering plants in the Mineville and Port Henry area and at Lyon Mountain. This article will deal with the properties in the vicinity of Mineville and Port Henry. In 1938, when Republic leased the Mineville- Port Henry operations from the Witherbee Sherman Corp., these properties had just come through some hard depression years. As a result, the mine development program was far behind schedule; most of the equipment needed replacement; and above all, the entire system of mining had to be completely changed to reduce operating costs. The concentrator had been in operation for many years; the process was dry and dusty. Machinery and equipment were either badly worn or entirely obsolete. The sintering plant, also long in operation, was badly in need of repairs.

Jan 1, 1943

By H. J. Gerritsen

From presently available components a portable, rugged, reliable apparatus can be built which will be able to detect methane concentrations of 0.1% and lower in air. Sensitivity and design considerations of the apparatus are given. Ways to build even simpler and cheaper apparatus in the future are indicated. Traditionally the problem of detecting and monitoring the presence of dangerous gases present in small concentrations in air has been a difficult one. Whether canaries,' or sophisticated chemical or thermal conductivity methods are used, they seem to be either slow, cumbersome, or otherwise not completely satis factory. A seemingly natural way of gas detection is to measure the strength of absorption undergone by light of a wavelength that the gas to be detected absorbs. This method has been difficult to apply in view of the low power output over a narrow wavelength range in the infrared from traditional glow bar light sources. Besides, the apparatus to select such a narrow band of wavelengths is quite costly and complex. The use of a laser solves these problems simultaneously. Although a variety of lasers are available to detect a variety of gases (such as carbon monoxide or methane) whose early detection would be desirable, this paper deals exclusively with the use of lasers for methane detection. ABSORPTION SPECTRUM OF METHANE IN AIR The absorption spectrum of pure methane is very well known.2-4 There are four fundamental vibrations, all occurring in the infrared of which only two absorb strongly. They occur at 3.3 µ and 7.7 µ. The absorption spectrum is quite complicated due to the fact that the methane molecule can rotate in a variety of rotational quantum states. These rotational states are furthermore split by anharmonic forces such as the Coriolis force.4 When methane is present in air at atmospheric pressure, much of the very fine structure due to the anharmonic force is washed out since the pressure broadening is of the same magnitude as the splitting due to anharmonicity. For most of the spectrum at 3.3 µ, the rotational lines are typically separated by 0.01µ while the individual linewidth is 0.0001 µ. It is thus very important that the laser emit at a wavelength that coincides with one of these rotational lines. Before elaborating on the point that such a laser exists and how it performs, it is necessary for later discussion to point out that in the

Jan 1, 1967