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By T. S. Hutchinson, C. E. Kemp

The bottom water drive analysis presented by Muskat has been extended to include fields with wider well spacings. Curves are presented from which volumetric sweepout, water-oil ratio, and rate relations may be calculated. The effects of non-unity ratios on sweepout eficiency and productivity decline have been studied by an approximate method. Also, the effect of gravity on volumetric sweepout has been approximated for a particurlar geometry. INTRODUCTION The purpose of this paper is to report work done in applying the analysis of bottom water drive reservoirs given by Muskat1 to a larger class of reservoirs, to extend this analysis to include the effects of gravity and non-unity mobility ratios in an approximate manner, and to investigate the rate of decline of productive capacity. The bottom water drive type reservoir is one where the oil is underlain by a water zone of sufficient thickness that water movement is essentially vertical. This system is defined in more detail in the appendix and a one well element is shown diagrammatically in Fig. 1. Muskat obtained solutions to the equations describing the volumetric displacement efficiency of idealized bottom water drive systems by assuming that gravity effects due to differences in density betwecn oil and water were negligible and that the mobilities of oil and water were the same. If either of these assumptions is not made, the complexity of the system makes an analytical solution well nigh impossible at the present stage of mathematical development. Coles and Stade' developed an approximation to consider these factors. The authors have refined approximations, starting with the same basic assumption, which should give a somewhat quantitative picture of bottom water drive performance when mobilities are not equal and the effects of gravity are not negligible. The results of these approximate calculations can then be used to obtain the decline in well productivity as the field is depleted.

Jan 1, 1957

By Ralph E. Esarey, Robert G. Reno

DriLLing activity and prospecting for oil and gas increascd in Indiana in 1941 over the previous year. The greater part of the drilling and development continued to centralize in the Indiana portion of the Interior Coal Basin, in the southwestern part of the state, but other parts of the state were not neglected. Many wildcat wells were drilled, including a series of core tests through the mantle of drift on the southern flank of the Michigan Basin. These core tests have been followed by several unsuccessful production tests. Production tests were made also along the axis of the Logansport-Kankakec branch of the Cincinnati Arch. In all, 411 field locations and 141 wildcat wells were completed in Indiana during 1941; that is, a total of 552 wells, an increase of 3 2 wells over the previous year. The field tests resulted in 260 oil wells, 57 gas wells, and 94 dry holes; wildcats included 16 oil wells, 3 gas wells and 122 dry holes. At the end of the year, 53 field wells and 34 wildcats were drilling. Gibson and Posey Counties led the state, with 154 and 155 wells drilled, respectively. However, 125 wells produced oil in Gibson County, while 98 produced oil in Posey County. Twenty-five per cent of all wells drilled were wildcat; II per cent of these produced oil and 5 per cent produced gas. Grifin field continued to lead in drilling activity, with 157 successful wells and 20 dry holes (including important wells defining the field). Production is found in five pay zones (Tar Springs, Waltersburg, Elwren, Aux Vases and McClosky). It produced a major part of Indiana's estimated 7,200,000 bbl. of oil during the year. Heusler field, Posey County, expanded with 11 oil ells and 4 dry holes in the Waltersburg and Tar Springs. Vienna field, Posey County, completed four oil producers in the Mansfield sandstone, between 1200 and 1250 ft. The College field, discovered late in 1940, received three oil producers and two dry holes in the Aux Vases. Two new fields were discovered in Posey County during the year: Lamott pool, in the Tar Springs, at 1950 ft., had initial production of 55 bbl. on discovery. One producer and one dry hole have been drilled since. Mt. Vernon pool found saturation in both the Waltersburg and Cypress formations. The discovery well tested about 1000 bbl. per day; it tested the McClosky at 2764 ft. Seven producers have been drilled since the October discovery. Welborne-Switch pool found oil in the Cypress sand at approximately 2500 ft., with an initial production of 33 bbl. One more well in the area proved a dry hole. Gibson County had the following discoveries in 1941: The Patoka field was opened by a McClosky producer of 300 bbl. Another producing well has been drilled. An attempt was made to extend the Illinois Mt. Carmel field into Gibson County, Ind., and one producer of 24 bbl, was completed on the Indiana side. A dry hole has since been drilled, one location south. One small well was completed in the Mans. field at 1105 ft. in sec. 31, T.2 S., R.12 W., Gibson County promising a new field

Jan 1, 1942

By Robert G. Reno, Ralph E. Esarey

DriLLing activity and prospecting for oil and gas increascd in Indiana in 1941 over the previous year. The greater part of the drilling and development continued to centralize in the Indiana portion of the Interior Coal Basin, in the southwestern part of the state, but other parts of the state were not neglected. Many wildcat wells were drilled, including a series of core tests through the mantle of drift on the southern flank of the Michigan Basin. These core tests have been followed by several unsuccessful production tests. Production tests were made also along the axis of the Logansport-Kankakec branch of the Cincinnati Arch. In all, 411 field locations and 141 wildcat wells were completed in Indiana during 1941; that is, a total of 552 wells, an increase of 3 2 wells over the previous year. The field tests resulted in 260 oil wells, 57 gas wells, and 94 dry holes; wildcats included 16 oil wells, 3 gas wells and 122 dry holes. At the end of the year, 53 field wells and 34 wildcats were drilling. Gibson and Posey Counties led the state, with 154 and 155 wells drilled, respectively. However, 125 wells produced oil in Gibson County, while 98 produced oil in Posey County. Twenty-five per cent of all wells drilled were wildcat; II per cent of these produced oil and 5 per cent produced gas. Grifin field continued to lead in drilling activity, with 157 successful wells and 20 dry holes (including important wells defining the field). Production is found in five pay zones (Tar Springs, Waltersburg, Elwren, Aux Vases and McClosky). It produced a major part of Indiana's estimated 7,200,000 bbl. of oil during the year. Heusler field, Posey County, expanded with 11 oil ells and 4 dry holes in the Waltersburg and Tar Springs. Vienna field, Posey County, completed four oil producers in the Mansfield sandstone, between 1200 and 1250 ft. The College field, discovered late in 1940, received three oil producers and two dry holes in the Aux Vases. Two new fields were discovered in Posey County during the year: Lamott pool, in the Tar Springs, at 1950 ft., had initial production of 55 bbl. on discovery. One producer and one dry hole have been drilled since. Mt. Vernon pool found saturation in both the Waltersburg and Cypress formations. The discovery well tested about 1000 bbl. per day; it tested the McClosky at 2764 ft. Seven producers have been drilled since the October discovery. Welborne-Switch pool found oil in the Cypress sand at approximately 2500 ft., with an initial production of 33 bbl. One more well in the area proved a dry hole. Gibson County had the following discoveries in 1941: The Patoka field was opened by a McClosky producer of 300 bbl. Another producing well has been drilled. An attempt was made to extend the Illinois Mt. Carmel field into Gibson County, Ind., and one producer of 24 bbl, was completed on the Indiana side. A dry hole has since been drilled, one location south. One small well was completed in the Mans. field at 1105 ft. in sec. 31, T.2 S., R.12 W., Gibson County promising a new field

Jan 1, 1942

By d&apos, K. Mukherjee, C. R. Antonio, R. J. Maciag, G. J. Fischer

Tensile data indicate that over the range of strain rates 10-5 to 10-1 sec-1 and in the temperature range 298° to 743°K the flow stress at a given temperature may be expressed as: C0 = Cem where m changes abruptly at a critical strain rate of 10-2 sec-1. The Zener-Hollomon parameter was tested and found to be invalid except at temperatures exceeding 700° K. Values of AH calculated for temperatures above 700°K ranged from 30 to 47.5 kcal per g-mole. ThE flow characteristics of aluminum and aluminum alloys as a function of temperature and strain rate have been of interest to various experimenters for many years. Trozera et al.1 determined tensile flow curves for pure aluminum and concluded that the combined effect of temperature and strain rate on the flow stress could be related using the Zener-Hollomon parameter. More recently, Hockett2 proposed a relationship between compressive flow stress, temperature, and true strain rate which could be represented by a surface. Holt et al.3 studied strain rate effects on flow stress in a number of aluminum alloys at room temperature. It was determined that there is a critical strain rate above which a strain rate effect is observed. It was also reported that the strain rate sensitivity was significant in aluminum alloys in the "0" condition only. In a recent review paper McQueen4 has considered a number of mathematical expressions which have been used to describe the relationship between stress, strain rate, and temperature. These expressions have been applied to the flow characteristics of a number of different metals and alloys including aluminum. In the present work the strain rate sensitivity of 7075-0 aluminum was determined in the temperature range of 298° to 743°K. The tensile flow stress at 0.2 pct offset was obtained over a nominal strain rate range of 10-5 to 10-1 sec-1. EXPERIMENTAL Threaded tensile specimens were cut from a single heat of 7075-T6 aluminum. The composition of this heat is given in Table I. The test bars had a gage section 1.5 in. long by 0.250 in. diam and conformed to ASTM specification E-8-57T. After machining, the bars were annealed at 413° ± 10°C for 2 hr. They were then cooled to 260°C in 3 hr, and finally air cooled to room temperature. This treatment is commonly used to produce the "0" condition. Load-time curves at constant crosshead speeds were obtained at various temperatures using an Instron testing machine. Crosshead speeds ranged from 0.002 to 40 in. per min. A three-zone resistance tube furnace was used for the elevated-temperature tests. Temperatures were measured at three points along the gage length by means of suitably placed thermocouples. Each tensile bar was held at temperature for 30 min prior to testing and the maximum temperature variation along the gage length was kept below 1°C. In all, 275 samples were tested and each data point plotted is an average of at least two tests. In many cases the point represents up to six tests. RESULTS AND DISCUSSION Values of the flow stress at 0.2 pct offset at six different temperatures are plotted vs strain rate on log-log coordinates in Fig. 1. Over discrete ranges of strain rate, the data for each temperature fit the expression:

Jan 1, 1969

By AIME AIME

MICA is perhaps our No. 1. strategic mineral problem because of its large requirements in a variety of equipment for use in the military services, and because the principal source of this material has heretofore been British India, a source now threatened partly because of distance and lack of ships. [Block mica and bauxite were added to the "most critical" list published by the W.P.B. on Nov. 6.] No satisfactory substitute has yet been found for most of the uses of mica, which largely involve electrical insulation. Brazil is now our nearest and best major source of this material. No splitting plants have yet been established there but in 1941 we imported about a million pounds of block mica from that country and in 1942 that quantity will be considerably exceeded. In Brazil, mica is found almost exclusively in the pegmatite dikes along the mountain range bordering the eastern part of Minas Gerais. A belt, roughly 180 miles long by 100 miles wide, extends from Theophilo Ottoni to Carangolo. The principal mica-mining districts in this belt are the Governador Valladares area to the north and the Espera Feliz district to the south. The dikes are usually 10 to 50 meters wide and a mile or two long and intrude the old metamorphic schist formation. They are weathered and easily mined.

Jan 1, 1942

INTRODUCTION Trade financing is a particularly important component of short-term financing for a minerals company since errors, extra costs, or payment delays/defaults can easily wipe out the profit margin on a particular shipment or can cause problems when arranging purchases of e.g. reagents. It is required to make any minerals operation function and does not have to be cross-border to require proper management. Sources of working capital are as follows: 1. Extended credit terms from suppliers 2. Inventory loans from banks, finance companies 3. Accounts receivable financing or factoring 4. Credit lines or overdraft facilities from banks. TRADE CREDITS These are provided under the familiar terms "net 10 days" or payment due by the "10th day of the following month." Thirty days for payment is usual but longer periods can be negotiated with regular suppliers. Shipment may be made on open account with specified periods for settlement. In the mining industry, a custom smelter gains trade credit by paying for concentrates three months after the month of shipment. INVENTORY LOANS Various forms of inventory finance are provided via "floor-plan" or warehouse financing. A set percentage, usually 60%-80%, of a good-quality, readily saleable inventory item (e.g. bullion, concentrates, ingots) will be provided by a bank or finance company which will usually have security over these products and has a right to inspect the goods from time to time. Legal security will he achieved by warehouse receipts, floating liens, chattel mortgages, trust receipts, or through collateral management service companies. The latter certify control over stock or distribution outlets and often carry insurance against fraud. Costs range around 1.5% - 2.0% p.a. or more plus some fees to cover out-of-pockets or other costs. ACCOUNTS RECEIVABLES Accounts receivable financing is based on the company's generation of satisfactory receivables which are continuously assigned to a bank or finance company ("factoring"). Because of the risks in being able to collect receivables, such as payments to a smelter for its blister copper shipments to a refinery, this form of financing costs as much as 3% - 5% of the debt amount purchased plus an additional charge for processing paperwork. Receivables can be purchased with or without recourse and on a notification or non-notification basis to the client's customer to, respectively, pay the invoice directly to the bank or not. LETTERS OF CREDIT Letters of Credit ("L/C's") are a common feature of international trade finance whereby a bank, at the request of the buyer, issues a written undertaking to an exporter to pay a specified sum of money within a set time on presentation of previously specified documents. This undertaking means that the exporter is no longer relying on the credit standing and integrity of the foreign importer. A dispute about shipment does not otherwise affect the obligation to pay upon presentation of a "clean" set of documents. These documents include the hill of lading and other documentation, often on standard "form" bases. There are a number of conventions and techniques in L/C's such as irrevocable/revocable L/C's, time L/C's, confirmation/advising L/C's and transferable L/C's. These are tools to adjust for the varying risks that the importer will not pay. Other routes where one is comfortable with an importer include documentary sight hills (D/P hill), documentary term bills (D/A bill), and, of course, open account.

Jan 1, 1985

By P. Schwarzkopf, J. H. Brophy

A modification of the Mendenhall wedge blackbody1 has been used to determine solidus temperatures and to anneal alloys in the tantalum-rhenium binary system. The technique has proven to be simple and accurate with modest power requirements. For temperatures up to 2800° C a piece of 10-mil tantalum sheet was folded double and formed as shown in Fig. 1. The middle of the resulting ribbon filament was a cylindrical-shaped crucible with less than a 1/8-in. opening. After inserting a specimen in the cavity, the filament was clamped between molybdenum electrodes in a high vacuum chamber. A representative filament 2 in. long and % in. deep was heated to 2800°C with a current of 700 amp at 4 v. The specimen temperature was determined by sighting into the cavity with a Leeds and Northrup optical pyrometer. The twisted filament shape was necessary to avoid serious geometric changes during thermal expansion. For temperatures between 2800" and 3000°C a 4-mil tungsten filament was employed. To facilitate fabrication it was warm-folded, and a twisted segment of 10-mil tantalum was used to support one end to absorb thermal expansion. This element assembly required about 700 amp at 10 v to reach 3000°C. Two geometric modifications of the filament were helpful for solidus temperature determinations. A shallow chamber, with depth to opening ratio of 3 to 1, permitted direct observation of the specimen through the optical pyrometer. The fact that the specimen was visible permitted the melting point to be determined when sharp features on the specimen surface became rounded; it also indicated that blackbody conditions did not prevail. By standardizing against the melting point of molybdenum, the observed melting temperature was corrected by the following form of Wien's Law: in which T is the true temperature, To is the observed temperature, and K is a constant characteristic of the filament geometry and determined experimentally for the molybdenum standard. The resulting corrected melting point for each alloy served as a reference temperature for the second more precise filament geometry. With a 6 to 1 depth to opening ratio, the specimen was indistinguishable from the filament interior, indicating good blackbody conditions. Using this technique, a series of specimens was isothermally treated at temperatures above and below the corrected direct reading. Incipient melting was detected by visual or micrographic examination of the specimen after cooling. This procedure was checked with specimens of pure chromium, molybdenum, and tantalum. Table I represents the values obtained, together with the solidus temperatures in the tantalum-rhenium binary system determined by the same technique. The alloy specimens were approximately 1/8 in. in diam. They were pieces of 10-g buttons melted four times in a nonconsumable tungsten electrode arc furnace on a water cooled copper hearth in 2/3 atmos of titanium gettered helium. Several sources of error are possible in such temperature measurements. Within the accuracy of the pyrometer no gradients were detectable near the specimen, and element distortion was virtually eliminated by twisting the tantalum. Compensation was made for the 1/8-in. sight glass by inserting several identical thicknesses and extrapolating to zero thickness. As a result an additional 10°C correction was added to all observations in the temperature range of 2500" to 3000°C. The principal source of error was then in the operation of the

Jan 1, 1961

By R. S. Newlin

IN reality, the Butte district is the birthplace of the Anaconda Copper Mining Co., for it was here that strength was gathered and means provided for later expansions of the Company. The Butte district was organized at a miners' meeting on Aug. 20, 1866, primarily for gold placer-mining operations. Substantial amounts of placer gold were recovered from gulch gravels during the period 1862 to 1868. The earliest lode claim locations in the district were recorded in July and August 1864. Copper ore was first shipped, to Swansea, Wales, in 1866. In November 1866, according to the Montana Post, construction of a smelter was started to treat the silver

Jan 1, 1948

By F. O. Garrabrant

Power is furnished to the Climax Molybdenum Co. by the Public Service Co. of Colorado over two 100,000-volt lines to a bank of three 3333-kva. transformers 100/13.8 kv. These transformers are so designed that with the addition of forced cooling their capacity may be increased 33? per cent at 12,000-ft. altitude. Under present conditions, these transformers are operated at 140 Per cent of their rating with forced air cooling. On the secondary side of this bank there is a 15-kv., 1200-amp. Westinghouse oil circuit breaker provided with automatic reclosing relays allowing three successive short circuits before lockout. From this breaker 13.8-kv. power is transmitted to a central switching station (Fig. I) where all circuits radiate to the different operations of the property. Each circuit is protected by a 23-kv., 600-amp. oil circuit breaker with by-pass and isolating disconnecting switches. Mine Power at 13.8 kv. enters the mine through a ventilation raise over a three-conductor, size 1-0 varnished cambric insulated, leaded, steel-wire armored cable, insulated from 17 kv. This power is received and distributed through one switching station and four underground substations, shown in Fig. 2. No. 370 substation (Fig. 3) contains three a 13,800/440-volt, single- phase Pyranol transformers protected on the high-voltage side by a 600-amp. manually operated oil circuit breaker. This station serves 20 slusher-hoist motors, a 45-kw., three-phase, 220-volt electric furnace, a Massco hot miller for tempering and milling Timken detachable bits and a hoist with 175-hp motor on the No, 3 development shaft. Also at this shaft are three pumps. One two-stage pump, 1200 gal, per min., 500-ft. head, 3600 r.p.m., driven by a 150-hp. motor, is at the bottom of the shaft, Two deep-well pumps, 500 gal. per min., 500-ft. head, are at the collar of the shaft. under normal operation the one pumping 1200 gal. per min, is controlled by a float switch to take care of the water. If this pump fails, or if its capacity is insufficient, the first 500-gal. pump is automatically started1 and if still more capacity is needed the second 500-gal. pump automatically starts. Time delay relays are provided on the deep-well pumps, so that if power fails the column will have time to drain before the Pumps restart. On failure of any Of these, an alarm is sounded in the train dispatcher's office, so that mechanics can be sent to ascertain the cause of failure and make repairs. The cable from No. 37' substation is run to the switching station, in which are four 15-kv., 600-amp. direct-current sole-noid-operated oil circuit breakers. The current for Operating and tripping is furnished by a 125-volt storage battery. All breakers are operated from the switchboard in the compressor room. One circuit from this switching station goes to the

Jan 1, 1946

During the year terminating at the date for the third annual meeting of Engineering Foundation, the Board completed, its undertaking to sustain the National Research Council for one year. Assistance given in the organization of the National Research Council has been amply justified by the results. The Council is now well established in a 4¬story building at 1023 16th Street, N. W., Washington, and has recently secured another similar building near by in order to house its increasing force. The breadth, importance and volume of work done have steadily grown. Foreign offices have recently been established in London and Paris, Dr. H. A. Bumstead being in charge of the former and Dr. William F. Durand of the latter. The total expenditure by Engineering Foundation for the National Research Council was $9,036, derived partly from income of the endowment fund and partly from special gifts from Ambrose Swasey and Edward D. Adams. In May, Walter M. Gilbert was appointed Assistant Secretary of Engineering. Foundation, with headquarters in Washington, his services being contributed by the Carnegie Institution. He also became and has remained to date Assistant Secretary of the National Research Council. In September, resolutions were exchanged between the Engineering Foundation Board and the National Research Council, setting forth a policy of continuing reciprocal relationship, and a conference committee, Chairman M. I. Pupin, Dr. Charles Warren Hunt, and Gano Dunn, was appointed to inform the National Research Council of the readiness of Engineering Foundation to work upon definite problems sug-gested by the Council. No problems have yet been suggested.

Jan 5, 1918

By J. R. Stone, G. D. Storm

Design features and operating methods of ASARCO's new unit for the continuous melting and casting of tough pitch copper at Perth Amboy are described. Preliminary studies made for determinitzg economic feasibility and design details are also presented. Cathodes are preheated with oil and melted in an electric furnace at 40-ton per hr rate, from whence the molten copper is fed simultaneously to the wire bar casting wheel and the continuous casting of cakes and billets. In the early 1950's the copper refining furnaces at ASARCO's Perth Amboy plant reached a point where major expenditures would have to be made for replacement of the furnaces and the auxiliary equipment. The problem was whether to continue with the standard reverberatory furnaces or to consider continuous melting in electric furnaces. Reverberatory furnaces have been used for years in the copper industry and for some 50 years at the Perth Amboy plant. Reverberatory melting practice, however, imposes certain restrictions. First, labor costs are high, usually requiring three shifts per day. Secondly, they operate on a batch basis, the conventional operation being a 24-hr cycle including

Jan 1, 1961

By Simon D. Strauss

What are future prospects for U.S. mining? In many quarters the assumption is made that this country has passed its zenith as a mineral producer -- that it is in a period of decline and that it is becoming a have-not nation like Japan and much of Western Europe. These industrial rivals of ours must depend almost entirely on others for their mineral supplies. In trying to answer this question one must of course distinguish between resources and productive capacity. In today's volatile and competitive markets, the definition of what are reserves and what are merely identified resources becomes ever more difficult. Many large deposits have been found that are unlikely to be viable in the marketplace under normal conditions but that can be of significance to the nation's military and industrial security in times of emergency. I should like to draw on personal experience from World War I1 for illustration. 4fter Pearl Harbor great concern developed over the availability of a long 1ist of strategic materials for which this country was largely dependent on imports. Included were a number of minerals of which domestic deposits had been identified. Among these were chromite, manganese ore, mercury, mica and tungsten.

Jan 1, 1982

By Hans Lundberg

AFTER the war years, great activity has been shown in geophysical exploration for ore. The appreciation by mining and government geologists of geophysical techniques and results is largely responsible for the popularity of these methods. In Canada, plans are being made to study, by geophysical methods, the structure of a portion of the Pre-Cambrian shield in the hope that such studies will not only give a clearer picture of the geology, but will be of direct aid to the mining companies when selecting areas for detailed prospecting. Although geophysics thus has become more popular, some engineers are still reluctant to employ the methods to their full extent. Allotted funds are often rather low, so that the least expensive

Jan 1, 1947

By L. G. Evans, C. Rampacek, G. A. Freeman

A large aggregate tonnage of oxidized and mixed oxide-sulfide copper ore of the southwestern U.S. is not amenable to conventional flotation concentration or sulfuric acid leach treatment. Most of the ores contain chrysocolla as the principal oxide copper mineral, for which no successful commercial flotation method has yet been developed. Acid leaching some ores is not feasible since they contain substantial quantities of calcite and other acid-consuming constituents. Other ores decrepitate during leaching or contain excessive slime and clay minerals which cause plugging of the ore beds.

Jan 10, 1961

By Ronald C. Whiting

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

Jan 1, 1938

By M. Kashiwada

The zinc leach residues are introduced into waelz kiln to fume volatile metals and before the end of 1967, the waelz-fume containing zinc, lead, cadmium and indium was directly recycled back to the leaching process for the production of electrolytic slab zinc. However, since 1968, we have been recovering with success those valuable metals contained in the fume separately instead of direct leaching. According to the improved process, the waelz-fume, after being mixed with chloridizing agents, is fed into the rotary kiln to be roasted, wherein most of lead and cadmium content is collected as fume and most of zinc remains in the calcine. Zinc calcine thus obtained, containing 70 to 75 per cent zinc and, less than 1.0 per cent lead is sent to zinc plant for further recovery and the fume containing 40 to 50 per cent lead and 3 to 6 per cent cadmium is further processed to recover lead, cadmium and indium. The advantage of this process can be secured to the utmost when it is combined with the following subsequent treatments. (a) Blast furnace smelting of non-magnetic waelz slag to recover copper, silver and gold as matte. (b) Gallium recovering process from magnetic waelz slag. (c) Soda process of lead bearing cake produced after removing cadmium and indium from the said fume. Thus the extractions of zinc, lead and cadmium from leach residues account for 87 per cent, 72 per cent and 85 per cent respectively.

Jan 1, 1970

By Richard Kunter

INTRODUCTION Additional work has been done on the CIP circuit at Creede, and a brief description of this work is presented in this paper. DREDGE The original dredge for the Bulldog was built by Al Hack, Inc. of Denver. The dredge cutter head is mounted on a boom made of 6-inch diameter pipe which is raised and lowered by a cable-pulley system. Maximum cutting depth is 8 feet. Slurry from the dredge flows through a floating 6-inch diameter pipe supported on 55-gallon drums which runs from the dredge to the shore and then to a trash screen and pumping system. See Figures 1 and 2. The cutter head, suction pump, winches for dredge movement, and all other operations are controlled from a small operations house located toward the rear of the dredge. All of the basic dredge equipment is mounted on a chassis about 8 ft x 16 ft in size. Additional buoyancy was originally provided by sealed 55-gallon drums supported along the sides of the chassis by a small wooden framework. Additional framework and barrels on the front of the chassis on either side of the cutter boom provided additional stability, particularly when digging in hard material. The dredge was quite stable, but two problems were apparent. For one, it could have been sunk by someone from the shore firing a rifle into all of the barrels. In prime deer-hunting and sportsman country

Jan 1, 1983

By H. Ries, R. E. Somers

Bodies of pyritic ore in schistose rocks have long been known in different parts of the world. The several occurrences resemble each other in being usually of more or less lenticular shape, inclosed in walls of schist or gneiss, and carrying pyrite, chalcopyrite, and pyrrhotite in varying proportions, as the chief ore minerals. The deposits differ, however, in that sometimes one, sometimes another, of the three sulphides mentioned may predominate. The orebodies in general are more or less closely conformable with the schistosity of the wall rocks, although in cases this may not hold true. The boundaries may or may not be sharp, but in general are fairly distinct. The lenses vary in size, may occur singly, or in groups; in the latter case they may be in line, overlapping, or occasionally parallel. Pinching and swelling of individual lenses is not uncommon. The genesis of these pyritic bodies has provoked much discussion, and they have been variously classed as sedimentary, igneous intrusions, hydrothermal replacements or impregnations, etc. Indeed, in some cases different geologists have most positively assigned widely diverse origins to the same deposit, as in the case of Rio Tintol and Rammels-berg.2 It is true that in the light of modern criteria, we have been able in a few cases to decipher clearly the process of origin and so there seems no. doubt now regarding the genesis of the deposits at Rio Tinto, Spain;3 Rammelsberg, Germany;4 Ducktown, Tenn.;5 southwestern Virginia;=

Jan 1, 1918

By Burnham E. Field

TAE chemical industry is constantly looking for new materials which either are more resistant to corrosion than those now available or have improved physical properties to meet the requirements of higher temperatures and greater pressures. Attack by acids is-one of the more important forms of corrosion-and in the last few years the development of acid-resistant alloys has been quite rapid. Perhaps the most notable example is that of nitric acid, 'the problem of which has largely been solved by the chromium-iron and chromium-iron-nickel alloys. Sulfuric acid may be handled in lead, iron, or the iron-silicon alloys, depending on conditions. As to hydrochloric acid, no metal or alloy can be called entirely satisfactory for handling. this acid under plant conditions.1 The results of our investigations on the resistance of the nickel-molybdenum alloys to hydrochloric acid have been confirmed by those of Guertler, Rohn, Schulz, Jenge, and others,' but thus far only one such alloy has approached commercial production in Germany; this contains approximately 15 per cent. chromium and 7 per cent. molybdenum with the remainder chiefly nickel. Dr. S. W. Parr, as far back as 1914, developed a complex alloy known as "illium," with a nickel base and containing some molybdenum.3 Dr. Parr was primarily interested in an alloy for lining bomb calorimeters, and while illium does show good resistance to acid it is too expensive for general use. Two United States

Jan 1, 1929

By Christie A. Callender, Harry M. Dahl

The Hobson uranium deposit is located in Karnes County, Texas, along the prominent south Texas uranium trend. The uranium mineralization occurs in the Deweesville Sandstone of the Whitsett Formation of the Eocene Jackson Group. The host rock is a friable, fine-grained, well-sorted, highly porous and permeable sandstone interpreted to be an ancient beach deposit. The sandstone contains significant volcanic constituents and ranges in composition from arkosic to tuffaceous. Locally, the host sandstone contains hard, dense opal cement. Bentonitic shales underlie and overlie the mineralized sandstone unit. Geometrically, the Hobson uranium-bearing zone resembles an elongated roll front type deposit. Chemical uranium values compared with gamma ray equivalent uranium values indicate that the uranium has been dissolved from the updip side and precipitated on the down- dip side of the roll front. Details of the uranium mineralization were studied using thin section microscopy, autoradiography, x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. The uranium mineralization occurs in the pores of the sandstone, as grain coatings and as replacement of sand-size and smaller grains. It is commonly associated with pyrite and other opaque minerals. Other favored hosts for uranium (other than pore openings) appear to be clay aggregates, altered rock and glass fragments, and carbonaceous plant debris. Aggregates of coffinite were identified by XRD and SEM/EDS analyses. Some uranium mineralization also appears to be dispersed and is postulated to be adsorbed on the clay and carbonaceous matter.

Jan 1, 1985