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By Wayne E. Tuomi

The mining industry is faced with a pressing problem; that is, to develop more efficient methods of extraction, handling and upgrading-techniques that will do the job faster and better than ever before. New techniques require new machines, or applications of new and improved materials that can be used to modify and improve existing machine and equipment designs. The traditional approach has been to increase productivity by increasing equipment size. Prognostication indicates that the trend toward larger equipment sizes and capacities will continue as one answer to the challenge imposed by future increases in mineral demands. But what is the limit on the continued growth of equipment size? Until about 1930, there was a very definite limit-a limit imposed by the strength of the steels and the power plants then available. The equipment engineer had come to an impasse: even though it was easily possible, for instance, to triple the size of a bucket, it had become impractical to correspondingly enlarge the boom, the counterweight, and the power plant.

Jan 3, 1967

By R. E. Somers

I. Introduction...........................604 1. Location, Topography, and Climate...............604 2. Scope of Work and Acknowledgments...............606 3. History and Mining......................606 11. General Geology.........................609 1. Introduction...........................609 2. Granite. :..........................610 3. Quartz Porphyry......................... 612 4. Monzonite........................... 614 5. Volcanic Breccia........,................ 618 6. Gravels............................. 619 111. Economic Geology......................... 619 1. Introduction........................... 619 2. Mineralogy........................... 619 3. Occurrence of the Ores...................... 622 4. Oxidation and Downward Enrichment............... 630 5. Rock Alteration........................639 6. Genesis of the Ores........................ 643 I. Introduction 1. Location, Topography, and Climate The Burro Mountains are located in the southwestern part of New Mexico, in Grant county. The group is made up of two distinct mountain masses, known as the Little Burros and the Big Burros, the former lying about 6 miles southwest of Silver City, and the latter about 9 miles farther in the same direction. They are separated by the valley of the Mangas River, a tributary of the Gila, and a stream only in name, except after a heavy downpour of rain. The Little Burros attain an elevation of 6,625 ft. above sea level, and the Big Burros 8,054 ft., with the surrounding country averaging about 6,000 ft. To the south of these mountains stretches the desert plain, while to the north are the more frequent elevations of the mountainous country.

Jan 1, 1916

The following list comprises the names of those persons who became members during the period May 10, 1916, to June 10, 1916: ARCHIBALD, JOHN CHRISTIE, Min. Engr., Supt. of Cyanide Plant, Guanajuato Reduction Mines, Guanajuato, Mex. BRUNEL, FRANK P., Cons. Min. Engr Mitchell & Brunel, Ajo, Ariz. CALVERT, WILLIAM ROBERT, Cons. Geol. ...225 Kearns Bldg., Salt Lake City, Utah. CHAMPION, J. R., Supt The Yak Mining, Milling & Tunnel Co., Leadville, Colo. CHARLES, LAVERN JOHN, Construction Engr., Elephant Butte Dam, Elephant Butte, N. M. CHASTEL, ANDRE, Min. Engr., Societe Miniere & Metallurgique de Penarroya, 12, Place Vendome, Paris, France. CHRISTIE, WALLACE H., Vice-Pres. and Mgr., Alt. Bert Gold Dredging Co., 604 Mission St., San Francisco, Cal. CLARK, RONALD ..Hardinge Conical Mill Co., 120 Broadway, New York, N. Y.

Jan 7, 1916

I would like to congratulate the authors on an interesting paper and, in particular, on their justification of the use of superposition in treating gas wells. They state, however, that no theory has previously been developed lor treating the variable rate drawdown case. In a paper published a few years ago by my colleagues and myself, a method is described which allows a constant rate drawdown curve to be derived for any well. regardless of real rate variations. This method has the great advantage that it is not necessary to make any assumptions regarding the form or uniformity of the reservoir, and the derivation suggested by the present authors is simply an idealized case of our more general treatment. In the light of several years' experience in the derivation of constant rate drawdown curves: I would like to point out that the method proposed by Odeh and Jones may lead to confusing answers, particularly if applied over an appreciable time interval. The reason is that, if pressures are measured when a well is flowing, non-linearities in plots like Figs. 1 and 2 can arise due to either (1) changes in the skin factor with time and/or flow rate, or (2) an inhomogeneous reservoir. Separation of these two effects is only possible if some of the pressures used in the analysis are measured when the well flow rate is 0 or, in other words. during brief shut-in periods. REFERENCES 1. Arthur, K. B.. Metunomski, Z. G. and Ruche, Ms "Intetet ct methode d'utilisa tion des mesures de pression [)our Petude des gisemonts" Revue de T'I.F.P. (Nov., 1962) XVII, 1299. 2. Thomere, R. and Arthur, K. R.: "Analysis of the Pressure Bet~avior of a Production Well Subject to Interterence and Its Application to Reservoir Models", Paper SPE 1189 presented at SPE :Amund Fall Mecting Ireld in Denwer, Colo. (Oct. 3-6, 1965).

Jan 1, 1966

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By William Glenn

In their account of chromium, Roscoe and Schorlemmer (Treatise on Chemistry, London, 1879) state that "In 1762 Lehmann, in a letter to Buffon, de nova minerœ plumbi specie crystalline rubra, described a new mineral from Siberia, now termed crocoisite." In 1786 Lehmann analyzed it (Nicholson's Jour., Dee., 1798) and found that it contained chiefly lead, and that the " mineralizers " were arsenic and sulphur. It was next examined in 1189 by Macquart and Vauquelin, who stated that it contained an intimate mixture of iron, alumina, and lead peroxide. The account of their work was published over the name of Macquart. Vauquelin (Louis-Nicolas) was a Norman peasant, who had studied in the village school, and at the age of fourteen was a laboratory-boy in a pharmacy at Rouen. Later, he found his way to Paris, and in 1789 was assistant to Fourcroy, a pharmacist and a teacher of note. It was here that he met Macquart, with whom he did the work on Siberian red lead, and at this time his friend Cheradame taught him his Latin.

Jan 1, 1896

By Michael A. Devane, Neil Duncan

Inclines and tunnels can extend from ground surface to considerable depths traversing a wide range of lithologies. The strata encountered may be affected by loosening and induced stresses at different locations along the route. It is suggested that Phase I of the pre- driving assessment process should include study of the geology, hydrogeology, rock material and rock mass characteristics. A rock mass disruption factor is used to express the ratio of the unconfined strength of intact rock material to the unconfined strength of in situ rock mass. It is suggested that there is a relationship between in situ (secondary) permeability values and the disruption factor, since the permeability of the rock mass is governed by parameters which influence strength. In Phase I1 of the pre-driving assessment, consideration should be given to the prediction of primary loosening which results largely from disturbances to the rock mass arising from the driving process. Also in Phase 11, preliminary assessments are made of the effects of induced stresses and of the geodurability characteristics of the rocks. In Phase 111, the mechanics of various secondary loosening pro- cesses are considered along with their relevance to estimates of stand up time and support requirements. Yield-line analysis is introduced for the study of plastic and brittle type bending deformations. Stand up time and support characteristics are also assessed. In Phase IV, the effects of induced stresses are analysed. It is suggested that even for broken rock in the Yield Zone, the rock mass disruption factor may not often increase above lo which is equivalent to an in situ permeability of 10-1 m/s.

Jan 1, 1983

By T. A. Rickard

The Cripple Creek district occupies a cluster of foot-hills on the south side of Pike's Peak and is a portion of an extensive, though uneven, plateau which unites the eastern range of the Rocky mountains with the Sangre de Cristo. It is essentially a small volcanic area, of about 20 square miles, amid the granite of the Front range. But though, when regarded as a rich mining district, it may be considered as an isolated area,* yet, geologically, it is, as Whitman Cross has pointed out, only an outlying portion of a much larger volcanic region, which stretches to the south and west, around Silver Cliff and the Rosita hills, forming the picturesque country cut by the deep cañons of the Arkansas river and its tributaries. The mines are situated amid a volcanic complex, consisting of tuffs and breccias which have been penetrated by an extensive system of dikes and other intrusive masses. The prevailing formation is an andesite breccia, which lies upon the worn surface of the granite and fills the deep basin around a volcanic vent. The breccia, since its deposition, has been broken into by several eruptions of phonolite and, later still, by a series of thin dikes of basalt and other allied rocks of a highly basic composition. The successive sedimentary formatione which, elsewhere in Colorado, lie upon the basal granite, are not represented in the district; whatever sediments were laid down before the volcanic period must have been removed by erosion, and there is very little evidence which affords a datum-line whereby the geological age of the volcanic eruptions can be determined. Whit-

Jan 1, 1901

By O. R. Bergmann

Two approaches were taken to obtain direct experimental evidence jar the existence oj a jet in the explosion-cladding pvocess: 1) direct observation of the claddirg jwocess by rtzeans ojf kig-h-speed photography using a fvartziiy catnera and 2) use of a plated-surface experiment in contribution with clzetrzical analysis. The framing-camera records showed clearly the presence of a jet it1 the form of what appears to be a line spray. The jet velocity is considerably highev than the detonation velocity arid in vacuum it is almost twice as high as the detonatiou velocily. The results jrorrz the plated-surface experiment also corzfivtned the preseizce of- a jet. The artzoutlt o,f etzergy dissipated in the jetting process was foundd lo be consislent with the basic theovetical model o/ the cladding mechanism.. MaNY reports on metal working with explosives have appeared in the literature during the last few yearsThis paper describes experiments concern- ing the mechanism of the explosive metal-cladding process. It has become increasingly important as a unique method for bonding metals and a typical cladding arrangement is shown in Fig. 1. A theoretical analysis of the mechanism of explosive bonding and a description of the nature and types of bond zones obtained was given by Cowan and oltzman." A further discussion of the basic principles of the process, a detailed description of the different bond-zone types, and extensive information on the properties and the applications of explosively bonded metals was recently published by Holtzman and cowan. " The process is now in commercial use by E. I. du Pont de Nemours & Co. The concept of the existence of a jet during metal bonding with explosives forms a central part in the theoretical analysis of the cladding mechanism described by Cowan and Holtzman When a layer of explosive is detonated on a metal plate that is separated from a second metal plate by a small distance the metal plate in contact with the detonating explosive is accelerated by the detonation pressure. An angle is established between the undeflected and deflected portions of the plate. Subsequently the deflected portion of the first plate collides with the second metal plate.

Jan 1, 1967

By Thomas T., Read

IT is difficult to judge how much influence the success attained during its first year, 1864-65, by the School of Mines at Columbia had on developments in education for the mineral industry elsewhere in the immediately subsequent years. The facts are as follows: 1. The Massachusetts Institute of Technology began giving instruction in February 1865, with a mining course included in its curriculum. 2. Early in 1865 the faculty of the Department of Science, Literature and the Arts of the University of Michigan requested permission from the Regents to establish "a course of study to be called the School of Mines . . . Also that the degree of Mining Engineering, be conferred on students who should complete the course of study prescribed in the same." A resolution authorizing this was adopted by the Regents on March 28, 1865. 3. Samuel Hooper endowed a Sturgis-Hooper professorship of geology at Harvard in 1865 with the intention of making it a nucleus of a new School of Practical Mining and Geology. 4. Yale appointed Alfred P. Rockwell professor of mining in 1865. 5. Lafayette College appointed Henry S. Osborn professor of mining and metallurgy in 1865. 6. Washington College (as Washington and Lee was then known), rising out of the ashes of Civil War destruction, made a fresh start in 1865, with Generalized as its president, and offered a mining course in the first catalogue thereafter published. 7. Lehigh University, founded in 1866, had a mining curriculum from its beginning. 8. Rensselaer Polytechnic began offering a curriculum in mining and metallurgical engineering in 1867. It would be natural to suppose that these events were a reaction, to the success of the school at Columbia, - and possibly they

Jan 1, 1941

By H. V. Flagg

OPERATION of a modern steel plant presents a curious anomaly. Large-scale operations, in which large volumes or heavy weights of materials are involved, are not usually subject to close control or narrow specifications. On the other hand, operations that call for a high degree of precision are usually carried out under carefully controlled conditions with delicate, precise machinery and tools, and production is made secondary to quality. In a modern steel mill both extremes are taken as a matter of course. A strip mill making auto-body sheets must supply its customers with sheets that all come within a tolerance of plus or minus 0.003 in. in gauge at any point from side to side or end to end, and without blemishes either of color or surface. Sheets that were considered par excellence as recently as ten years ago could not even find a market today. Such exacting requirements have made necessary a nicety of control that approaches the watchmaker's art. Notwithstanding this necessity for precision, the scale of operation is stupendous.

Jan 1, 1940

By John F. Wiggert

DURING the early years of Homestake operations, shaft signaling from the cage tenders to the hoisting engineers was done by mechanical means. Small steel cables or jointed steel rods were suspended in the shaft compartments and counterbalanced with weights or springs. These cables or rod strings were connected to the mechanically operated gongs at the engineers' stations by means of bell cranks and steel wires. The system was simple and economical and served the purpose well until the mine reached a depth of 1000 ft., then the system became slow and cumbersome and required a considerable amount of muscular effort to operate it with much speed, because of the inertia of the heavy moving parts. The mechanical signaling was superseded by a simple electrical system consisting of a single pair of wires in steel conduit for each shaft compartment. In the shaft at each station a pull switch was connected to the wires. The switches were operated by means of bell cords, which extended from station to station. This electrical system was a great improvement over the mechanical one, but it had one serious drawback, which also applied to the older system; namely, the engineer did not know where a signal originated. Later on this signaling was improved to overcome this drawback, and to give the engineer a positive indication of a signal's origin. In this system a separate return wire from each pull switch is carried to an annunciator at the engineer's station, where it indicates the signal's origin. While the annunciator system used by Homestake is very safe and reliable, it has the inherent drawback of all wire-connected systems in that it is impossible to send a signal from a moving cage. A number of years ago Homestake became interested in the possibility of using some sort of radio transmission for shaft signaling. The company did much experimental work with purely radio signal transmission, but no practical way was discovered to use radio transmission in a mine shaft for signaling to or from a cage. Therefore, all efforts were directed to devising a practical way of using the hoisting rope as part of the circuit. It was realized that the return circuit from the rope would need to be through electrostatic coupling between the cage and the earth or ground sides of the shaft, because the guides would not always be wet enough to make possible good electrical contact between the cage and earth, therefore relatively high-frequency alternating current was chosen as the medium of transmission. Soon a practical system was developed for transmitting an electric current from a moving cage over an electric circuit of which the hoisting rope was a part. A high-frequency electric current is used as a carrier to transmit the signals or mes-

Jan 1, 1941

By Thomas L. Kesler

Essentially all of the barite produced in Georgia has come from the Cartersville district in the northwest part of the state. The earliest recorded shipment of ore, 60 tons, was made in 1894.1 With the exception of the four-year period 1931 to 1934, the separate yearly output has been recorded and published since 1915, whereas the total yearly output of the United States has been published since 1880. The separately recorded production of Georgia (Cartersville) through 1947 is 2,232,544 short tons valued at $14,900,746,2 but unpublished data on the period 1931 to 1934, plus the estimated unrecorded output prior to 1915, make the actual total about 2,400,000 short tons. This is about 21 pct of the total production of the United States, which, through 1947, is 11,328,440 short tons valued at $71,683,386.2

Jan 1, 1949

By M. R. Tek, K. H. Coats, D. L. Katz

A large number of boundary value problems encountcred in unsteady-state heat transfer, fluid flow through porous media, neutron diffusion and mass transfer involve the solution of a linear, parabolic partial differential equation commonly refcrred to as the diffusivity equation, where U is the dependent potential variable. K is the diffusivity (hydraulic, thermal, neutron, etc.) and 1 is the time variablc. Solutions to Eq. I are available in the literature for a wide variety of initial and houndary conditions. The great majority of these solutions are ohtained for geometric boundaries corresponding to linear. cylindrical or spherical flow models. A typical engineering application where the solution to Eq. 1 is required is the calculation of underground water encroachment across the boundaries of oil or natural gas reservoirs, In this particular area of application, the reservoir boundary is invariably approximated by circular geometry. However. the areal shape of many reservoirs can be better approximated by elliptic rather than circular boundaries. Thus the need for a general method of solving the diffusivity equation in elliptic coordinates arises in this problem as well as in other engineering applications involving elliptic boundaries. The solution to the diffusivity equation usually in volves the Error Function for the linear flow model, Bessel functions for the radial flow model and trigonometric or Legendre functions for the spherical flow model. It is well known that the general solution to the diffusivity equation in elliptic coordinates involves Mathieu functions. The significance of Mathieu functions in the analytical treatment of the diffusivity equation in elliptic coordinates is discussed in the literature However, these references do not providc analytical solutions useful in practical engineering problems. The objectives of this papcr are the development of the equations describing the unsteady-state liquid flow through a porous medium with an elliptic inner boun- dary, the development of a numerical method of solving these equations and, finally, a comparison of the water encroachment quantities calculated from the elliptic flow equation with those calculated from the radial flow equation. While the specific problem treated in this paper relates to unsteady-state liquid flow through a porous medium, the basic equations and computational techniques devcloped will apply equally well to problems occurring in the other areas of engincering interest mentioned previously. The solution given here is limited to a single case in which thc outer boundary encloses an area 100 times that of the inner boundary. DESCRIPTION OF THE FLOW MODEL Fig. 1 shows the flow model upon which the calcu lations presented in this paper are based. The inncr and outer houndaries of the flow model are represented by two confocal ellipses with major and minor axes, respectively, equal to 2a1, 2b1, and 2a, and 26,. The height of the elliptic cylinder flow model is denoted by 17. The following assumptions are employed in the development 01 the equations governing the unsteady-state liquid flow through the described flow model. 1. Uniform porosity and permeability throughout the flow model

By W. M. Johns

The geological mapping of Lincoln and Flathead Counties was a five-year project undertaken by the Montana Bureau of Mines and Geology. This paper, written by the Project Geologist of the survey, is primarily concerned with the stratigraphy of the Belt rocks encountered in mapping. Lincoln and Flathead Counties of northwestern Montana are underlain by sedimentary rocks of the Belt Series of Precambrian age. In only a very small part of the area, near Libby and Troy, have economic mineral deposits been worked with any success. Most of the area has been inadequately mapped as to geology. The region is crossed by the Great Northern Railway and served by the Pacific Power and Light Co.; officials of these two companies believed that with better geologic maps, prospecting might be stimulated and lead to the discovery of mineral resources that would contribute to new economic development within the area. A cooperative mapping agreement was proposed jointly by the two companies to the Montana Bureau of Mines and Geology in May 1958, and thus was born the Kootenai-Flathead five-year project. The dual objectives of this project are: 1) the possible location of mineral deposits of economic value, and 2) the ''stimulation of prospecting exploration" by others. This was to be achieved by geologic mapping of some 6800 sq miles and by establishing a field office in Kalispell where prospectors could come to have their rocks and minerals identified and receive geological advice on their problems. This writer has finished four field seasons as Project Geologist and thus became familiar with the Belt section in the Libby, Yaak River, Ural, Thompson Lakes, Pleasant Valley, and Stryker quadrangles (see Fig. 1). Progress on the project is given in annual reports issued by the Bureau.* This *Montana Bureau of Mines and Geology, Bulletins 12 (1959), 17 (1960), and 23 (1961). paper is concerned essentially with the stratigraphy of the Belt rocks so far encountered in mapping. PREVIOUS WORK IN THE AREA Willis28 made the first study of the stratigraphy and structure in the Lewis and Livingston Ranges of Glacier Park just east of the project area. In 1904, Daly made a study of the Belt rocks of the 49th parallel, using the names from bottom up, Creston, Kitchener, Moyie, and Gateway, for rocks ranging in age from that of Prichard to that of basal Missoula group. Walcott26 studied the Belt rocks exposed in the Mission Range (see Fig. 1) and other areas to the south of the area under discussion. Calkins and McDonald made a reconnaissance of northern Idaho and northwestern Montana in 1905. Calkins was the first to use Walcott's term 'Ravalli' as a group name for the strata equivalent to the Burke, Revett, and St. Regis formations (see Table I). Clapp worked on the Belt of western Montana (including Lincoln and Flathead Counties) throughout his lifetime. The Fentons9 studied the Belt of Glacier Park and

Jan 1, 1962

By F. S. White, E. L. Kinsella

THE solids fluidization process brought out by the Standard Oil Development Co. in the early forties for catalytic cracking of petroleum enabled rapid transfer of large quantities of heat from gases to solids under closely controlled temperature conditions. As the technique developed, it was natural that applications for the process outside the petroleum industry would be sought. The calcination of limestone to ' quicklime requires the transfer of a large quantity of heat at high and closely controlled temperatures. For these reasons, this possible application was one of the first to be investigated. Laboratory work conducted by the Dorr Co. indicated that lime produced by solids fluidization would be of exceptional quality. Calculation of theoretical heat balances showed that savings in fuel could be expected. Accordingly, a pilot plant of 10 tons per day capacity was erected by the New England Lime Co. at Adams, Mass., to substantiate the process. Operation of the pilot plant, previously described,1 showed that excellent lime could be produced with a saving in fuel. The work also indicated the necessity of preparing feed to remove the finer fractions if dust losses were to be held to a tolerable level. A single-stage fluidized solids drier-stripper was developed to accomplish this sizing.2 Subsequently a commercial lime reactor was erected at Adams, beginning operation in June 1949, followed by air sizer facilities completed in November 1951. This paper will describe these two applications of solids fluidization. The raw material for preparation of lime by the fluidizing process is a high calcium crystalline lime stone having the approximate chemical composition shown in Table I. The stone is first prepared by crushing and grinding in conventional equipment to pass a 6-mesh sieve. After crushing, the material is sent to the FluoDry unit for drying and dedusting. Fluidized Drying and Sizing As shown in Fig. 1, the FluoDry unit consists of a 1/4-in. cylindrical steel shell, 9-ft ID by 22-ft 6-in. overall height. Attached horizontally at the bottom is a 6-ft diam combustion chamber, approximately 7 ft 6 in. long. A refractory constriction dome, consisting of first-quality fire brick shapes, partitions the inside into two sections. The lower section is called the windbox and the upper the bed compartment. The vertical wall of the shell is lined with 6-in. first-quality rotary kiln blocks. In the bottom of the windbox a hoppered section is formed with castable refractory to permit the windbox to be readily cleaned via a 6-in. screw conveyor. The combustion chamber is similarly lined with refractory shapes. On the 6-in. diam section, 4 1/2 in. of insulating brick, HW-26, are used. The inner combustion chamber is lined with 4 1/2-in. Korundal brick to withstand the high flame temperatures encountered. An 8-in. steel feed pipe, entering vertically through the top and fitted with an air-operated cone valve,

Jan 1, 1952

By David B. Reger

Wildcat drilling for new supplies of gas and the expansion of previously discovered oil and gas pools were the principal petroleum activities in West Virginia .during 1942. Much of the new gas exploration is still uncompleted and still indecisive but various wildcats made substantial extensions to existing pools. Out of 53 wildcats drilled 27 resulted in commercial gas and 6 in commercial oil. Four of the oil discoveries also had commercial gas. No strictly new pools of oil or gas can safely be described as discovered but several scattered oil and gas wells previously drilled have been confirmed as the openers of definite pools; also, various completions closed wide gaps between apparent gas pools already discovered. The proved oil territory of the state was increased about 4850 acres and the proved gas territory about 51,000 acres. The new proved oil reserves should about balance withdrawals and the new gas may represent a substantial increase. Aside from the drilling in four rather lively pools, oil activity was slight because of unfavorable operating conditions and prices. Gas drilling also declined for reasons beyond the control of the operators. The account of operations, as gathered from trade journals and other reporting services, shows that 797 new wells were drilled, providing 119 new oil wells with 2762 bbl. of daily new production; 536 new gas wells with 1,228,501,000 CU. ft. of daily open flow: and 142 dry holes. Also... 76 old wells were drilled to deeper sands, with 71 bbl. and 26,034,000 cu, ft. of added production. On the new wells the oil average was 23.21 bbl. per well per day; and the gas average was 2,270,406 CU. ft. per well per day. On new wells the ratio of dry holes to completions was 17.82 per cent. On deeper drilling the ratio of failures was 21.05 per cent. Production of oil for the year was estimated by the Oil ad Gas Journal as 3,492,000 bbl., as compared with 3,378,000 bbl. in 1941. Production of natural gas for the year is estimated by the author as 220,000,000,000 cu. ft., as compared with the U. S. Bureau of Mines final figures of 207,000,000,000 cu. ft.* in 1941. General State op Industry Leasing of wildcat acreage increased considerably. The total land of all classes under lease may now exceed 5,000,000 acres. Taking into consideration completions, abandonments and corrected figures or estimates, Table I shows cumulative and late annual statistics. New Pools and Extensions Table 2 shows the principal areas of drilling activity during 1942. Various consolidations of territory, hitherto treated as separate pools, have been made. in addition to these active pools, extensive drilling was done in numerous other areas where pool boundaries can hardly be defined. Summary or Exploration Table 3 gives a summary of important wildcat or exploratory wells drilled during

Jan 1, 1943

By David B. Reger

Wildcat drilling for new supplies of gas and the expansion of previously discovered oil and gas pools were the principal petroleum activities in West Virginia .during 1942. Much of the new gas exploration is still uncompleted and still indecisive but various wildcats made substantial extensions to existing pools. Out of 53 wildcats drilled 27 resulted in commercial gas and 6 in commercial oil. Four of the oil discoveries also had commercial gas. No strictly new pools of oil or gas can safely be described as discovered but several scattered oil and gas wells previously drilled have been confirmed as the openers of definite pools; also, various completions closed wide gaps between apparent gas pools already discovered. The proved oil territory of the state was increased about 4850 acres and the proved gas territory about 51,000 acres. The new proved oil reserves should about balance withdrawals and the new gas may represent a substantial increase. Aside from the drilling in four rather lively pools, oil activity was slight because of unfavorable operating conditions and prices. Gas drilling also declined for reasons beyond the control of the operators. The account of operations, as gathered from trade journals and other reporting services, shows that 797 new wells were drilled, providing 119 new oil wells with 2762 bbl. of daily new production; 536 new gas wells with 1,228,501,000 CU. ft. of daily open flow: and 142 dry holes. Also... 76 old wells were drilled to deeper sands, with 71 bbl. and 26,034,000 cu, ft. of added production. On the new wells the oil average was 23.21 bbl. per well per day; and the gas average was 2,270,406 CU. ft. per well per day. On new wells the ratio of dry holes to completions was 17.82 per cent. On deeper drilling the ratio of failures was 21.05 per cent. Production of oil for the year was estimated by the Oil ad Gas Journal as 3,492,000 bbl., as compared with 3,378,000 bbl. in 1941. Production of natural gas for the year is estimated by the author as 220,000,000,000 cu. ft., as compared with the U. S. Bureau of Mines final figures of 207,000,000,000 cu. ft.* in 1941. General State op Industry Leasing of wildcat acreage increased considerably. The total land of all classes under lease may now exceed 5,000,000 acres. Taking into consideration completions, abandonments and corrected figures or estimates, Table I shows cumulative and late annual statistics. New Pools and Extensions Table 2 shows the principal areas of drilling activity during 1942. Various consolidations of territory, hitherto treated as separate pools, have been made. in addition to these active pools, extensive drilling was done in numerous other areas where pool boundaries can hardly be defined. Summary or Exploration Table 3 gives a summary of important wildcat or exploratory wells drilled during

Jan 1, 1943

By C. O. Tarr, G. V. Smith, R. F. Miller

METALLURGISTS have long recognized that the Fe3C type of carbide is not a stable phase in steel and that, given sufficient time, it will decompose with formation of graphite, at least at temperatures below about 2050°F.1 This slow graphitization has never been of much concern to users of hypoeutectoid steels, for in such steels it occurs only during prolonged exposure at elevated temperature. In 1935, Kinzel and Moore2 reported complete graphitization of the carbide of a 0.1 5 per cent carbon steel that had been in senrice for about 26,000 hr. at a temperature of about 1100° to 1200°F. In discussing this paper, both Mathews and Sauveur reported graphitization of slightly hypereutectoid steels. In an extensive investigation of graphitization of high-purity iron-carbon alloys, Wells1 produced graphite at 7o0°C. (1290°F.) in an alloy containing as little as 0.13 per cent carbon, and showed that graphite may precipitate either directly from austenite or from decomposition of Fe3C, also that the rate of graphitization tends to increase with increase of temperature, at least up to a certain point, and with the presence of graphite nuclei. Jenkins, Mellor and Jenkinson,3 studying the structural changes in carbon steels ranging from 0.17 to 1.14 per cent carbon during stress-rupture tests at elevated temperature, obsenred graphite in an aluminum-killed 0.40 per cent carbon steel after fracture in 4340 hr. under a stress of 17,900 lb. per sq. in. at 840°F. and in many of the steels after stress-rupture test at 1200°F. Unstressed samples of 0.60, 0.86 and 1.14 per cent carbon steels graphitized almost completely in 360 hr. at 1200°F., while samples of 0.90 and 1.10 per cent carbon steels were somewhat graphitized, and steels containing 0.24, 0.40 and 0.57 per cent carbon showed no sign of graphite. Their results indicate that graphite precipitates the more readily the higher the carbon content, though this tendency is influenced to some extent by deoxidation practice, and that graphitization is accelerated by plastic deformation. In a recent study of the graphitization of 0.4 and 0.6 per cent carbon steel strip, made by M. A. Hughes,4 it was found that at 1200°F. graphite appeared after 72 hr. in aluminum-killed but not in silicon-killed steel, and that the rate of graphitization was increased by slow cooling from 1600°F. and by cold-working prior to annealing. In creep tests of normalized o. I 5 per cent carbon steel killed with 2.5 lb. of aluminum per ton, at the U. S. Steel Corporation laboratory at Kearny, spheroidization and some graphitization were found after 3000 hr. at 1000°F. under a stress as low as 15m lb. per sq. inch.

Jan 1, 1944

The Pueblo Viejo Mine, a 7, 250 mtpd (8,000 stpd) gold-silver cyanidation plant built by Rosario Dominicana S. A., was described in Volume I of this monograph. At the time of writing that volume, Pueblo Viejo had not yet gone on-stream and operating data or costs could not be presented. Since that time this information has been obtained and several interesting modifications and an expansion have been made to the plant. Because Pueblo Viejo is the largest open-pit gold mine in the world and one of the world's leading gold-silver operations with production of approximately 31 kg (1,000 oz) gold and 125 to 155 kg (4,000 to 5, 000 oz) silver per day, the authors have updated the previous data and flow sheet. The Dominican Government, which held a 4670 interest in Rosario Dominicana S. A., completed purchase of the mine to gain full control in 1979. Rosario Resources will continue to manage the mine, at least until the end of 1980. Gold was produced at Pueblo Viejo almost 500 years ago with initial production in the year 1505. Rosario Resources became interested in the property in 1969 and found surface oxidation had rendered the upper portion of the ore body amenable to direct cyanide treatment. The treatment of the underlying gold-bearing sulfide zone is still undergoing metallurgical studies. The ore is considered to be a laterite; and because there appeared to be few boulders in the ore zone, only a 400 m (16 in. ) square grizzly was initially installed ahead of the mills when the plant went on-stream in late 1974 at a design capacity of 7,250 mtpd (8,000 stpd). Operation also proved the ore to be harder than was originally anticipated. During 1967 a 1. 25 m by 1. 5 m (48 in. by 60 in. ) jaw crusher was installed to -feed the 1, 000 mt (1, 100 st) mill bin. Minus 200 mm (8 in.) crushed ore is fed directly to two 5.5 m by 1. 8 m (18 ft by 6 ft) semi-autogenous mills re-powered with 750 km (1,000 hp) motors and 50 mm (2 in.) grates. Each mill product is screened at 13 mm (1 /2 in.) by a vibrating screen. Screen oversize from each mill is combined on a single return belt equipped with a magnetic head pulley for grinding ball removal. The non-magnetic oversize is then split into two fractions for return to the primary mills. Originally, a minus 6 mm (1/4 in ) product was made on each screen and fed to a 300 kw (400 hp) 2.6 m by 3. 7 m (8-1/2 ft by 12 ft) regrind mill. During a plant expansion in 1978, an intermediate mill of 746 kw (1,000 hp) was installed to operate in open circuit on the combined primary mill

Jan 1, 1981