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By Herbert H. Einstein

The innate variability of natural materials and processes causes uncertainty in the models representing the natural phenomena and uncertainty in estimating the parameters that are used in these models. Reliability analyses, in contrast to the traditional factor of safety approach, are well suited to a rational incorporation of uncertainty in design and exploration decisions. Probabilistic kinetic and kinematic analyses were developed and combined to form reliability analysis methods. With one method the reliability, i.e.) the probability of failure, of an individual 2-plane wedge in a slope can be determined. The other method is aimed at slopes with a single slope parallel set of joints. In each case two approaches were developed, an encompassing one relying on computer codes and a simplified or summary approach relying on charts or pocket calculator computation. A major contribution of these approaches is the treatment of joint persistance. Instead of having to assume a certain persistence, it is now possible to use exploration data on joint geometry and to include the persistence effect rigorously.

Jan 1, 1979

By Michael Horn

This report presents a structural analysis of the economies of Spokane County, Washington and 21 surrounding counties. An economic trading region made up of 22 eastern Washington, northern Idaho, and western Montana counties, with Spokane, Washington as the central place, was defined for this study. The Micro IMPLAN modeling system with the 1990 county database was used to create an Input/Output based model of the regional economy. The leading industries, with respect to employee compensation, employment, value of exports, and total industry output are shown for each county and the region. The value of total industry output from natural resource based industries is also shown (or each county and the region. The total industry output from the Spokane Economic Trade Area (S ETA) region is valued at $22.3 billion. The SETA region provides $7.1 billion in employee compensation to a work force of 374,000. Spokane County, Washington accounts for about 50 percent of the regional total output, employee compensation, and employment. Both Spokane County and the region as a whole produce about 80 percent of total industry output for final demand with the remaining 20 percent going to intermediate inputs for further production. About $7.4 billion of the $22.3 billion SETA output is exported from the region. Spokane County exports about $4.7 billion, or 41 percent of the $11.5 billion Spokane County output. Exports account for more than 50 percent of the total output in 12 of the 22 counties within the region. Based on the output of the top 25 industries in each county and the SETA region about 9 percent of the industry output from Spokane County and 18 percent of the regional industry output come from natural resource based industries. For counties other than Spokane County, total industry' output from natural resource based industries represents from 12 percent to 81 percent of county output from the top 25 industries. Natural resource industries account for more than 50 percent of total county output in 8 counties within the region

Jan 1, 1994

By Raghoottma S. Pandurangi, Mohindar S. Seehra

"The interaction of amorphous 1ilica particles with several hydrogen bonding agents (H2O, C2H5OH, C7H2NO) was investigated by monitoring the changes in the bulk and surface IR vibrational modes of silica using photoacoustic spectroscopy. It is argued that the intensity of the silanol band at 3747 cm-1 provides (an inverse) quantitative measure of the interaction or surface groups, along with the shift in the broad hydroxyl band, the interaction following the order C7H2NO > C2H5OH > H2O. Index Headings: Silica; Surface vibrational modes; Photoacoustic spectroscopy; Hydrogen bonding agents.INTRODUCTIONThe use of m spectroscopy to study the adsorption on solid surfaces is well documented in the literature.1 2 For example, hydroxylation of a clean silica surface results in the formation of the free silanol group Si-OH, with a sharp IR band near 3747 cm-1• Further hydroxylation produces a broad band near 3500 cm-1, which is believed to result from various hydrogen-bonded silanol bands leading to a multilayered surface structure of few nm.3-5 Earlier studies had indicated a relationship between the surface silanol band and various chemical activities of silica such as cytotoxicity, 7- 9 catalysis, 10-12 and others.13 Recent studies from our group14-in which the intensity of the silanol band and cytotoxicity of silica, heat-treated at various temperatures up to 1095°C, were investigated have provided a strong correlation between cytotoxicity and intensity of the silanol band.Coating of silica by PVPNO (polyvinyl-2-pyridine N-oxide with the empirical formula C7H8NO), a strong hydrogen bonding agent, is known to reduce the cytotoxicity of silica, presumably by chemically blocking the silanol groups from phospholipids.15 This interaction of the hydrogen bonding agents with the silica can be studied by m spectroscopy, and Knozinger16 and Rouxlet and Semples11 have used transmission m spectroscopy to study the effect of various chemicals on the surface IR modes of silica. However, one of the major disadvantages of transmission IR spectroscopy is that the sample preparation (grinding and mixing with KBr and pelletizing) usually distorts the surface modes (see, e.g., Ref. 14) and there is always a doubt about the effect of the sample preparation on the measured properties. In recent years, photoacoustic (PA) spectroscopy has become the technique of choice for studying the IR spectra of samples in their natural state, since no sample preparation is necessary.18•19 Moreover, according to a recent paper, 20 the relative intensity of the surface modes in PA spectroscopy of silica particles is much higher than that in transmission FT-IR spectroscopy. Consequently PA spectroscopy is ideal for studying the surface chemistry. In this work, we have used PA spectroscopy to investigate the interaction of three hydrogen bonding agents (C7H8NO, C2H50H, and H20) with the silica surface by monitoring changes in the surface m modes. Our results show that the surface IR modes get perturbed to a larger extent than the bulk IR modes in interaction with the hydrogen bonding agents. Moreover, whereas in the earlier studies, the shift of the broad silanol band near 3500 cm-1 was used as a measure of the interaction with hydrogen bonding agents,16•17 here we show that the relative decrease in the intensity of the sharp silanol band near 3747 cm-1 also serves as a quantitative parameter for the relative surface coverage and surface modification. Details of this work are given below."

Jan 1, 1990

By W. B. Berwald

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gras association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating; this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying; results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made.

Jan 1, 1931

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The tactual data obtained during the project are reported in a series of Reports of Investigations beginning with No. 4251, of which this is the twelfth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate halt-township map. The description of each half township is followed by a description of each deposit developed in that halt township. The 14 half-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each half township is given with the discussion covering that area.

Jan 1, 1948

By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By C. Lorimar Colburn

"The use of helmets during the war has accentuated interest in the advisability of using stiff hats in mines to protect the miners against falling rocks. About forty per cent of the accidents in mines are due to falling rocks or roof. A large number of these accidents could be prevented if the miners wore stiff hats or helmets.The use of head protective devices in minas is not new, for they have been in use for many years in Europe and in the Lake Superior District in the United States. In practically all of the mining districts in Europe stiff hats of some kind are required by the mine management. George S. Rice, chief mining engineer of the Bureau of Mines, reported that in Germany, Belgium, and France stiff hats made of papier mache or felt rosin are in use. Similar hats are generally employed in the Lake Superior District. In building the subways of New York and Philadelphia it was the practice of engineers and workers to let the hair grow very long and to wear a close fitting cap or felt hat. In Germany the hats are high like the military helmets, whereas in France and Belgium they fit more closely to the crown. In England the practice is mixed. As a rule the miners use soft padded caps, but in Yorkshire many of the miners use sole leather, tight-fitting caps of jockey pattern with the seam forting a little ridge down the middle of the cap. These hats are very useful allow thin beds of coal, as in crawling one is very likely to strike his head a sharp piece of rock or on a timber. Of course, such mishaps are more likely to occur to a man not familiar with the mine. It must be admitted such hats do not stick on well, though this is usually due to their not being especially fitted. The German hat is particularly unsuited to an American-shaped head.It is interesting to note that on the continent tight cotton caps are generally worn over the hair and under the hard hat. This is a measure for cleanliness which is excellent. In low beds of coal share much crawling on hands and knees is necessary the dirt and coal dust sift down, making the miner black and dirty. In metal mines stiff hats are of especial use in shaft work; also in raises or high stapes. A small fragment of rock falling some distance either down a shaft or raise would kill a man if it struck him squarely on the head. A stiff hat or helmet may protect him and save his life. At a station in a shaft where men are loading the cage or skip, some kind of adequate head protector should be compulsory. A head-protecting hat or cup which is also a good insulator should be worn where there is danger of striking one's head against a wire carving an electric current."

Jun 1, 1920

By E. P. Dowding, J. Schlocker, C. H. Fuchsman, R. R. Lloyd, Mahan. W. M., O. C. Garst, W. T. Rawles

"INTRODUCTION The United States, although the leading consumer of chromite, depends almost entirely on imports for its supply. For instance, the consumption during. 1941 amounted to 714,645 long tons, whereas the domestic chromite production, although the highest since 1918, was 12,731 long tons or only 1.78 percent of the domestic consumption. 9/ Domestic production was tremendously, accelerated,after 1941 by war demands; however, only a small proportion of this domestic product was of sufficient quality to be substituted for the high-grade imported chromite demanded for metallurgical purpose. Chromite is used largely for making ferrochromium, an alloy containing 60 to 70 percent chromium which is used in making alloy steels. Peacetime specification for ferrochromium required that it should contain 68 to 69 percent chromium. These specification were lowered to between 60 and 63 percent, chromium in 1941 to permit the use of lower-grade ores. The specifications for metallurgical chromite, used for making ferrochromium, were established first by the Metals Reserve Company at 48 percent Cr203 and a Cr. Fe. ratio of 3 : 1 but later were lowered to 45 percent Cr203 and a Cr : Fe ratio of 2.5 : 1. The ratio of chromium to iron in chromite is important, because the contained iron enters the alloy in making ferrochromium and, although an ore may contain the required 45 percent Cr203, it may contain too much to be suitable for ferrochromium production. The principal sources of domestic chromite are California, Oregon, Montana, and Alaska minor, small, and widely scattered deposits in another dozen States. Without exception, these deposits are low-grade, require beneficiation to produce a commercial product, and are not competitive with imported high-grade ore in normal times. Nevertheless, these deposits form strategic reserve, which must be utilized in periods of national emergency. Recognizing this fact; the Bureau of Mines for many years has undertaken investigations to develop methods of utilizing domestic chromite ores. The problem has been approached from three angles: (1) Mechanical methods of concentration; (2) beneficiation by chemical or metal¬lurgical methods; and (3) production of metallic chromium by electrolysis of solutions prepared from ore or concentrate."

Feb 1, 1946

By Gordon E. Green

This report addresses remote monitoring of coal waste impoundments for stability. Existing automated geotechnical monitoring systems are described and reviewed along with details of instruments suitable for such systems. An impoundment in West Virginia which was in the construction stage was instrumented and monitored between July 1979 and may 1981. Sensors which measure surface and subsurface parameters including settlement, horizontal deflection, surface tilt, pore water pressure, seepage, pond level, and meteorological parameters were installed. Data from the 37 sensors were collected by on-site logger and transmitted by telephone to a central processing station in Seattle for recording and interpretation. Difficulties were encountered with telephone and powerline outages and malfunction of electronic units. Detailed descriptions of the design and performance of the system are provided along with evaluation and comparison with other systems. Recommendations for improving and expanding the capabilities of the monitoring system are given.

Jan 1, 1982

By G. W. Jones, F. E. Scott

"INTRODUCTION During the last war, considerable attention was given to the search for materials or combinations of materials for use as expelling agents for aerosols in the well-known ""aerosol bomb."" These materials must be free of fire and explosion hazards under normal conditions of use.In cooperation with the Department of Agriculture and other Federal agencies interested in the work, the Bureau of Mines carried out a laboratory investigation on the inflammability of- dimethyl ether-dichlorodifluoromethane air mixtures. 4/The method of investigation was essentially the same as that used in a similar investigation dealing with the inflammability of propane-butane-dichlorodifluoromethane mixtures. 4/SOURCE OF MATERIALSThe dichlorodifluoromethane (commonly known as freon-12) and the dimethyl ether were supplied by Dr. Lyle D. Goodhue., U. S. Department of Agriculture, Beltsville, Md. It was reported that the freon-12 was manufactured by the Kinetic Chemical Co. Wilmington, Del., and the dimethyl ether by the Carbide & Carbon Chemicals Corp., Charleston, W. Va..The materials were obtained in small metal cylinders and were used as received. Before using, the cylinders mere placed in an upright position, and 5 to 6 liters of the gas was released from each cylinder to the atmosphere to remove any trapped air that may have been introduced when the cylinders were filled."

Sep 1, 1947

By W. B. Berwald

The United States Bureau of lanes, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the problem of the flow of natural gas through high-pressure transmission lines. Numerous data on gas flow through pipe lines under many conditions of operation have been obtained by carefully conducted tests, and these data, together with all other available information, have been analyzed Carefully to secure practical facts for the use of operators in designing pipe lines and determining the effects of different operating conditions on pipe-line capacities. The first procedure in initiating this problem was to review, compile, and analyze all of the existing data on the flow of natural gas through pipe lines. Actual data applicable to pipe and operating conditions normally used in the transmission of natural gas were meager, and the several pipe line flow formulas developed by different investigators gave widely varying results when applied to problems of pipe-line design. Therefore, further experimental work under conditions comparable to those found in transmitting natural gas was essential before any definite recommendations could be made. The problem, as originally planned, included flow tests on pipe lines in operation, and in each test the measured delivery vas to be compared with the delivery calculated from several common pipe line flow formulas.

Jan 1, 1931

By W. A. Stickney, J. W. Town

Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .

Jan 1, 1964

By R. B. Prater

The Bureau of Mines conducted research to separate the F from byproduct Zn concentrates obtained from fluorspar (CaF2) production, as part of the Bureau's effort to devise efficient, environmentally acceptable technology for recovering Zn from resources considered undesirable by Zn producers. Sulfuric acid (H2SO4) was found to be effective in F removal, while ammonium carbonate [(NH4)2C031 was not. The most important variables for reducing the necessary residence time were found to be temperature and agitation. Optimum leaching conditions were 75° C and 500 r/min for 2 h at 40 pct solids with 0.2 g acid per gram of concentrate, which resulted in a 98.3-pct F extraction. Zinc losses during F removal were in the range of 2 to 3.3 pct. Other elements such as Fe, Cd, Ca, and Cu were also partially dissolved. About 93 pct of the F was removed from the leach solution by neutralization and precipitation with calcium hydroxide [Ca(OH)2]. Additional treatment might be necessary to limit the buildup of soluble elements in the recycled leach solution.

Jan 1, 1985

By T. O. Llewellyn

The Bureau of Mines, as part of its goal to develop technology that can conserve domestic mineral resources investigated beneficiation methods for recovering phosphate minerals from two Southern Florida deposits with high magnesium content. Chemical analyses of sized fractions indicated that no coarse pebble concentrate could be produced from either deposit. Conventional fatty acid-fuel oil batch flotation tests on two phosphate samples, analyzing 6.8 and 8.5 pct P205, yielded concentrates containing 28.97 to 29.80 pct P20S at recoveries ranging from 72.4 to 76.9 pct of the flotation feed. The MgO content ranged from 1.20 to 1.36 pct. Bubbling S02 gas through an aqueous concentrate slurry, further reduced the MgO content of these phosphate concentrates to 0.5 and 0.8 pct, but with a concomitant loss in the phosphate recovery. Settling characteristics of slimes from both phosphate samples showed a slow settling rate, which is a typical characteristic of other slimes in the region.

Jan 1, 1981

By E. L. Litchfield

Four short-term studies of practical ignition problems were undertaken and completed during the course of the Bureau of Mines project "Development of Specifications for Intrinsically Safe Equipment." Conclusions were as follows: (1) the most easily ignitible mixture of propane-air in a PTB break flash apparatus is approximately 5.2 percent propane; (2) miniature lamp bulbs to be used in intrinsically safe circuits are about as incendive to coal dust-air as to methane-air and should be tested in gas mixtures containing about 7.0 to 7.5 percent methane; (3) the sodium amalgam contained in high-pressure sodium lamps does not present an ignition hazard for coal dust or methane, where the lamps contain no more than 30 milligrams of amal-gam; (4) the maximum allowable surface temperature of permissible electrical enclosures should remain at 150° C despite efforts by industry groups to raise the value to 200° C.

Jan 1, 1980

By W. G. Park

Long-range projection of demand for domestic crude oil indicates a continued upward movement and accentuates the need for increasing the recovery from known crude-oil resources to supplement expected future discoveries. Consequently, the industry and Government have given special attention to the viscous or heavy-oil deposits because they offer the distinct possibility of large order increases in ultimate recovery. This report presents data pertaining to 150 heavy-oil reservoirs in Arkansas including oil characteristics of samples from 38 of these reservoirs. To January 1, 1967, about 600 million bbl of heavy oil has been recovered from the 150 reservoirs in 63 oilfields; however, about 4.5 billion bbl, or 88 pct, of oil remained in the ground. Of prime importance is that much of this heavy-oil resource is in reservoirs having characteristics considered favorable for thermal-recovery operations. Data for the thermal projects initiated [thus Ear are presented in individual field discussions. Also discussed is the t crude oil supply-demand situation in the State.

Jan 1, 1969

By Robert N. Roby

"The Moffet-Johnston property was investigated by the Bureau of Mines with the object of determining the presence of ore reserves that might be utilized during the war emergency. Preliminary examination was made during May and Juno 1943, as a result of which the Johnston 'tunnel was cleaned out and repaired, the .mime was surveyed, and a small program of exploration was undertaken. This report describes the work performed and presents the data obtained.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts prelimi¬nary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs benefication tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.The chemical and spectrographic analyses were made at Reno, Nov., under the direction of A. C. Rico, acting engineer in charge, Rare and Precious Metals Experiment Station, Bureau of Mines. The ore-dressing tests were under the direction of Rollien R. Wells, metallurgist, at the Salt Lake City laboratories of the Bureau of Mines.The author acknowledges the cooperation and assistance of the lessee of the property, H.R. Hakes, who furnished nine reports and other information.The Moffet-Johnston property is in secs. 2 and 3, T. 3 S., R. 5 W., in the Tidal Wave mining district of Madison County, Montana.The portal of the Johnston adit is near the mouth of Bear Gulch, 9 miles northeast of Twin Bridges, Mont. It is reached by an improved dirt road that serves mining properties farther up Bear Gulch. The Moffet mine and the Mountain View shaft are now accessible from the Bear Gulch road over an access road recently completed by the U. S. Grazing Service. The Grazing Service road has also been supplemented by bulldozer trails built by the Bureau of Mines.An electric-power line extends from the Montana Power Co's substation at Twin Bridges to mines at the head of Bear Gulch and passes within 200 feet of the Johnston portal.The claims of the Moffet-Johnston property were located about 1900. A report by H. V. Winchel, consulting geologist, in 1904 indicates that most of the development on the Johnston adit was completed by that date. At the time of the Winchel report, the Moffet workings had just penetrated the first ore shoot (fig. 4)."

Sep 1, 1946

By Gergely Markos

Uranium mill tailings represent a potential threat to the human habitat by containing large amounts of radioactive and chemically toxic substances in high concentrations. These: undesired components enter the human habitat in various pathways such as by erosion and water or air transport. The main objective of this investigation was to evaluate the actual movement and model the potential movement of contaminants by seepage of water from the tailings into the subtailings soil. This report represents various models of the movement of contaminants using both theoretical approaches and empirical evaluation of data available from other investigations. The data consist of field measurements and laboratory determi¬nations of major and trace cations, the dominant anions, pH, and Eh of moist solids, extracts, and waters from the tailings and surroundings. Evaluation and interpre¬tation of data were accomplished by using Eh-pH diagrams, various statistical methods and the WATEQFC computer program. Data analyses show that the critical area of investigating movement- is the interfaces between tailings and the external environment. The chemical differences at interfaces seem to result in a sink system for contaminants. The tailings-soil¬-water system shows extreme complexities because of chemical and physical hetero¬geneity of the system preventing the use of a single comprehensive model to represent real conditions. The validity of the simplifying assumption used has been shown and increasing complexity has been built into the models. Analogs of these models can be used for evaluation of similar systems.

Jan 1, 1981

By Sidney Katell

This report covers the period January 1962 through December 1962; it is a continuation of the series that began with the publication of Information Circular 7510 in October 1949. Also, it is the fourth in a series of reports prepared under a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers. The agreement provides for the publication of an annual cost bibliography with the work load evolved in the preparation shared equally. The abstracted articles, concerned with all facets of cost engineering in the field of chemical and petroleum plants and related subjects, are from tile following sources: 1. American Association of Cost Engineers Bulletin. 2. Bureau of Mines Information Circulars. 3. Bureau of Mines Reports of Investigations. 4. Chemical Engineering. 5. Chemical Engineering Progress. 6. Chemical Week. 7. Coal Age. 8. Coal Utilization. 9. Cost Engineering. 10. Hydrocarbon Processing and Petroleum Refiner. 11. Industrial and Engineering Chemistry. 12. Nucleonics. 13. Oil and Gas Journal. 14. Petroleum Management. 15. World Oil.

Jan 1, 1963

By B. W. Jong

As part of the Bureau of Mines program to develop substitute or improved performance refractory materials for metallurgical applications, the Tuscaloosa Research Center has evaluated the effect of additives on sintering and strength properties of aialon (silicon aluminum oxynitride) compositions fabricated by a conventional powder metallurgy technique. Additions of Y203, Gd203, CeO2, MgO, ZrO2, ZrSiO4, and MgA12O4 to a sialon composition containing 70 pct ß-Si3N4 + 30 pct a-A1203 increased sintered densities by as much as 50 pct over densities of undoped material. The studies also indicated that sintered densities reached a maximum between 20 and 30 mole-pct a-A1203 when a series of sialon compositions of a-Si3N4, having 6.7 to 57.9 pet a-Al203, were doped with Y203, Gd2O3, and MgO. In studies to establish the effect of the crystalline phase of the silicon nitride and alumina used, tests were made using a- and ß-Si3N4 and a- and ?-A12 03 as starting materials. The tests indicated that when using an addition of 5 wt-pct Y203, best results were obtained with a sialon composed of 74.4 mole-pct a-Si304 and 25.6 mole-pct ?-A1203. In other tests made with this sialon composition MOR values of 28,120 and 29,500 psi at 25° C, and 23,520 and 16,850 psi at 1,400° C, were obtained when doping with 5 wt-pct ZrSiO4 and ZrO2, respectively.

Jan 1, 1980