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By J. V. Scalera

Because of U.S. dependency on imported critical metals, the Bureau of Mines has conducted research to evaluate the possible substitution of nitrided low-alloy steels for higher chromium-containing alloys. The corrosion data for nitrided steels are limited primarily to the Soviet literature. The objective of this study was to determine the corrosion properties of six commercially nitrided low-alloy steels in a 5-wt % NaCl solution at pH 4. Weight-loss tests indicated that, in deaerated test solutions, most of the nitrided steels were less corrosion resist-ant than nontreated steels. However, electrochemical tests indicated that under more oxidizing conditions, nitrided materials are converted to a passive state with a significantly reduced corrosion rate. Elec-trochemical tests performed in an aerated environment confirmed the passivity of the samples in an oxidizing environment.

Jan 1, 1984

By R. A. Beall, W. E. Anable

The purification of hafnium by electron- beam melting at moderate energy inputs and at low pressures was examined in detail . Most metallic impurities and hydrogen were removed in the first few minutes of operation ; oxygen , carbon , and nitrogen were removed at a slower rate . Samples treated by electron bombardment suffered a small loss of weight and a gradual lowering of hardness . The magnitude of each change varied with the energy input and the duration of the melt . Analysis of the data confirms the loss of oxygen as a hafnium monoxide . Approximate activity coefficients for other contaminants are given .

Jan 1, 1964

By Scott W. Hazen

This report presents the results of a statistical analysis of a limited amount of sample and assay data from a production panel in an open - pit phosphate mine in the Phosphoria formation in Idaho . A frequency distribution analysis is shown for the assays , sample interval lengths , and products of assay and sample interval length for the millshale , furnace - shale , and main phosphate beds . Correlation techniques were used to show the relationships between assays and sample interval lengths . Within- drill - hole and between - drill - hole correlation were also examined as a means of predicting grade trends in the ore . Simulation methods , utilizing a digital computer , were used to establish assay populations that could be used for estimating grade of ore , cutoff grades , and deposit or bed identification .

Jan 1, 1964

By Raymond W. Hiteshue, Sam Friedman, Robert Madden

Experiments were made in a semicontinuous unit to provide engineering data for designing experimental continuous systems . These systems would be used to study the hydrogasification of hvab coal and char (from lowtemperature carbonization ) to high - Btu gas . In experiments at 800 ° C and with a coal residence time of several seconds , yields of hydrocarbon gases increased from about 2,000 scf / ton of maf coal at 250 psig to 7,000 scf at 1,000 psig . With 15 minutes residence time , yields increased from 8,000 scf/ton of maf coal at 250 psig to 17,500 cubic feet at 1,000 psig . In all cases , small quantities of heavy oils were produced along with the gaseous hydrocarbons . Production of oils could be minimized with a corresponding increase in gaseous hydrocarbons by increasing the retention time of the volatiles within the hot zone . Yields of gaseous hydrocarbons from char were slightly greater than from coal under similar conditions . Although the hydrogasification reaction is very pressure dependent , substantial quantities of coal (40 to 60 percent ) could be reacted to gaseous hydrocarbons at pressures as low as 50 psig provided reaction temperatures were increased to 1,200 ° C. It was also demonstrated that a hvab coal could be hydrogasified continuously without incurring agglomeration . This was achieved by dispersing coal in a relatively large reactor with concurrent flow of hydrogen . At 1,000 psig and 800 ° C , it was possible to react about 35 percent of the coal and to produce a gas containing up to 52 percent methane .

Jan 1, 1964

By R. W. Smith, S. H. Ash

Marked progress in safety has characterized the operation of coal mines in general in the State of Washington during the 5- year period 1928-1932 , particularly during the years 1931 and 1932. Physical conditions such as steep pitches , inherently bad roof and floor , prevalence of gas , and explosibility of the dust of Washington coals present certain definite hazards . Although advances have been made in accident reduction in Washington , the State still has far to go in that direction . The State has endeavored to reduce its coal -mine accidents by the usual method of making certain definite safety requirements mandatory . The value of education has not been underrated , but the educational method used has not altogether achieved the res lts desired by the industry itself , particularly within certain imdividual organizations . The past 2 years have witnessed a growth , in certain instances , of the essential ideas that the observance of safety precautions on the part of all is demanded if accidents are to be reduced , and that the initiating and carrying out of any program to promote and obtain desired results in accident elimination must begin and function from the top downward . Mining operations of Washington mines have been described in various publications of the United States Bureau of Mines .

Jun 1, 1933

By Paul Hatmaker

Pumice and pumicite are siliceous volcanic substances quite similar in chemical composition , but somewhat different in physical properties , manner of formation , and mode of occurrence . Production in the United States has increased from 23,271 tons valued at $ 94,943 in 1910 , to 56,843 tons valued at $336,099 in 1930. Both pumice and pumicite are included in these figures as it has been impractical to collect statistical data on the separate commodities .

Mar 1, 1932

By Carl N. Anderson

This paper, which is one of a group presented by the United States Bureau of Mines covering mining practice in different districts, deals in particular with the methods employed in mining the horizontal type of zinc-lead orebodies of the West Baxter area of the Tri-State zinc and lead district. These orebodies, locally termed "sheet-ground" bodies, with their relatively low working faces and low tenor of zinc and lead, require changes in the mining practice which is used in the balance of the district. In addition to the general mining methods, this paper also describes the system of hand sorting employed prior to the direct milling of the ore. The Hartley mine is situated mile west of Baxter Springs, Kans., as indicated in Figure 1. Its general outline and the location of the shafts with respect to the milling plant are shown in Figure 2.

Jan 1, 1932

By Larry Gsellman

This report presents the results of a benefit/cost analysis of the Bureau of Mines' Coal Extraction RCD Program for the period FY 1977 through FY 1982. The analysis is an update of the analysis performed on the Coal Extraction R&D Program for EY 1975 - FY 1980 and presented in a MITRE report, MTR-7225, published in May 1975. Major changes included: new production scenarios and an update of R&D cost estimates.

Jan 1, 1977

Laboratory tests were conducted by the U.S. Bureau of Mines to determine respirable dust reduction effectiveness of and interaction between face airflow and water sprays for a continuous miner. Increases in exhausting face ventilation from 3,000 to 9,000 cfm, in waterflow from 15 to 35 gpm, and in water nozzle operating pressure from 80 to 200 psi were evaluated. Results indicated that airflow had the greatest individual impact on reducing dust levels, with concentrations at return and operator sampling locations reduced by as much as 57% and 99%, respectively. Regression modeling was utilized to predict dust concentrations over the range of values tested for the control parameters. Interactions between the control parameters were significant and often defined an optimum level where further increases in that parameter failed to produce additional dust reductions. Increasing airflow to 8,400 cfm, waterflow to 25 gpm, and water pressure to 140 psi typically reduced dust concentrations at operator and return locations. Application of a control parameter above these levels can provide additional dust reductions if used in conjunction with appropriate levels of the other two control parameters. Otherwise, higher operator dust levels may result and can be attributed to increased rollback and/or airflow turbulence.

Jan 1, 2010

By J. T. Dunham

Zirconium has possible use in industry where severe corrosion conditions are encountered because it resists attack from a variety of corrosive environments. However, very little experimental testing has been done to evaluate the corrosion behavior of zirconium when simultaneously subjected to high tensile stresses and exposed to corrosive environments. This investigation was initiated for an evaluation test, but was limited to environments consisting of ferric chloride solutions which were known to attack zirconium and were shown to promote stress-corrosion cracking in preliminary tests. Tests for cracking susceptibility were conducted by the Bureau of Mines to show the effect of stress, solution concentration, air aeration of solution, and the method of mechanical processing. Tensile stress was applied to the specimens by a constant-load method which proved more reliable than a constant-strain method.

Jan 1, 1961

By C. J. Wilhelm, John M. Devine, Ludwig Schmidt

"Steel tanks often corrode rapidly in oil fields where the Gas produced with crude contains an appreciable quantity of hydrogen sulphide. In many instances working tanks have been discarded after only six months of service because of failure induced by corrosion.Aluminum has been used for some time in the fabrication of certain equipment incidental to the handling of oils containing hydrogen sulphide gas in solution, and has exhibited no carious corrosive action. These uses indicated that aluminum tanks,be equally effective in counter- acting hydrogen sulphide corrosion. Consequently, in the spring of 1920, an all-aluminum stock tank of 500 barrels capacity and a ""composite"" tank of equal capacity, having a steel bottom and bottom ring and an aluminum top and top ring, were placed in service on the State-Lassiter lease of the Gulf Production Co, in Crane County, Tex. These tanks were under observation for one year, the toot being sponsored by the Gulf Production Co., the Aluminum Co. of America, and the Parkersburg Rig and Reel Co. The results of this preliminary test sustained the belief that aluminum is highly resistance to hydrogen sulphide gas and likewise indicated the type or grade of aluminum which could be most economically used for lease tankage. However, in this preliminary test the tanks were not subjected to contact with the quantities o highly concentrated brines such as often are associated and produced with crude oil. Therefore, it was suggested by representatives of the aluminum Co. that additional tests be made to include production conditions in large quantities of brine would be handled, for pact experience had shown that aluminum often is susceptible to the corrosive action of brines."

Apr 1, 1931

By John E. Hamak

The identified helium resources of the United States were estimated by the U.S. Bureau of Mines at 617 Bcf, as of December 31, 1992. This includes 285 Bef of demonstrated reserves, 85 Bcf of demonstrated marginal reserves, and 37 Bcf of demonstrated sub-economic resources. The identified resources also include 166 Bcf of helium in inferred reserves and inferred marginal reserves and 44 Bcf in inferred sub-economic resources. The identified helium resources contained on Federal lands are approximately 172 Bcf, including 32 Bcf in underground storage in the Cliffside Gasfield near Amarillo, TX. Undiscovered helium resources in the United States are estimated at a most likely volume of 104 Bef, with a maximum volume of 249 Bcf and a minimum volume of 41 Bef. Also reported are 51 Bcf of helium in nonconventional and low-helium-content natural gases. Extraction of helium in the United States occurs mostly from natural gases produced from the Hugoton gas area in Kansas, Oklahoma, and Texas, and the Riley Ridge area in southwest Wyoming. Helium extracted from natural gas in the United States in 1992 was 3.3 Bcf. Some shortfalls in helium supply may occur in about 5 to 10 years.

Jan 1, 1995

By T. M. Romslo

"The Keystone and St. George properties are in the so-called Johnson Camp area and adjoin a property that in recent years has become a steady producer of low-to medium-grade copper-zinc ores. The Keystone Copper Co. was active intermittently from 1908 to 1938 and during 1926 to 1937 produced a recorded 1,100 tons of 5 percent copper ore. There is no evidence that ore has been produced from the St. George property.In the Johnson Camp area both igneous and sedimentary rocks ranging in age from pre-Cambrian to Quaternary are exposed. The ore bodies are in the Paleozoic rocks and occur principally in the Abrigo formation, which is composed mainly of limestones and shales. The rocks of the productive zones are metamorphosed and are cut by systems of fractures and faults. Chalcopyrite and sphalerite, the principal ore minerals, replace altered limestones to form deposits locally called mantos and chimneys.Investigation of the Keystone and St. George deposits by the Bureau of Mines included topographical and geological mapping of the surface and the underground workings and diamond drilling from the surface. A total of 10,067.8 feet was drilled in 22 holes. The drilling started November 13, 1947, and was completed August 19, 1948.This report records factual information obtained during the course of the investigation."

Jul 1, 1949

By R. H. Church

As part of the research effort of investigating the effects of microwave energy upon the chemical and physical properties of different minerals and ores, the Bureau of Mines has conducted basic research into identifying those properties of minerals that are affected by microwave energy, namely, the dielectric constant and loss tangent. These properties were determined utilizing the theory of microwave propagation in a coaxial waveguide filled with a dielectric material and measuring the input impedance with an RF impedance analyzer that operates from 1 MHz to 1 GHz. By knowing the microwave frequency and filling the waveguide with a powdered mineral, the dielectric properties of the mineral sample were determined. From these dielectric properties, theoretical microwave heating characteristics of each mineral could be calculated. These same mineral samples were then irradiated by a 915 MHz 30 kW variable power microwave oven and dielectric heating studies were performed. A comparison of the theoretical heating characteristics and the results from actual dielectric heating studies was conducted to evaluate the dielectric property measurements on each mineral. This report presents the results of the Bureau's research in identifying the dielectric properties of low-loss minerals according to the mineralogical classification scheme along with their irradiation studies. Though far from complete, this study represents some of the more frequently encountered low-loss minerals.

Jan 1, 1988

By Paris V. Brough

This paper, which describes the practice of milling custom ore, in addition to that produced under company and lease operations in the Tom Reed mines, is one of a series 'being prepared by the Bureau of Mines. ACKNOWLEDGMENT Acknowledgment is made to W. B. Phelps, managing director, and Jack Zwinge, superintendent, far permission to publish, a-ad to G. E. Jarpe, the present mill superintendent, for his assistance in preparing the paper. LOCATION The mill is in Oatman, adjacent to the Benjamin Harrison shaft of the Tom Reed Gold Mines Co., in the foothills on the western slope of the Black Mountains, western Mohave County. The railroad shipping point is Kingman, Ariz., 25 miles northeast of Oatman. Paved highway U. S. 66 passes by the mill. The altitude is approximately 2,700 feet.

Jan 1, 1937

By Brian M. Harney

The technique of remote sensing, used for many years by earth scientists, is being applied to the detection and monitoring of air pollution. Instrumentation being developed is of a very diverse nature and is effective, Fn varying degrees, at ranges from 1,000 meters to the altitude of a space satellite. This paper describes a number of the recent developments in this new field. Instruments based on spectroscopic, laser, and photographic systems are discussed. Sensors are being developed which utilize correlation spectrometry, interferometry, Raman scattering, Mie scattering, laser line absorption, and simple photographic detection.

Jan 1, 1973

By R. E. Hershey

1. Reserves were estimated for three coal beds: Lantana, Sewanee, and Richland. 2. Known measured and indicated reserves for all beds, based on a minimum thickness of 14 inches and on 1,800 tons per acre-foot of coal in place, are estimated at 34 million short tons as of Januray 1, 1954. Of this total, 15 million short tons represents coal 28 inches and more thick. Areas in the beds were omitted from the estimate because available data relative to the bed characteristics were insufficient to permit making an estimate conforming with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves determined by this investigation.

Jan 1, 1956

By S. H. Ash

THE INUNDATION of anthracite reserves in the Eastern Middle field of Pennsylvania affects the life of the anthracite industry in this field; it also influences the economic status of people, communities, and industries that depend wholly or in part upon anthracite for their livelihood. The trends of production and of employment in the anthracite-mining industry in this field are downward, and they probably will continue in this direction. The reserves have been depleted to the extent that the end of the active life of the industry as a. major economic factor is approaching. By removing the water in those pools where it can be done economically, the future of this industry may be extended somewhat.

Jan 1, 1950

By William O. Vanderburg

Some mines after passing through the prospecting stage and becoming sizable enterprises still adhere to the development program of the prospect, extending their workings without definite plans. In mining operations where definite structural conditions do not exist, a prearranged layout of mine development is not feasible; but where exploration and preliminary development have indicated the extent and probable limits within which the ore is expected, careful planning of development will result in a lowering of mining costs and a consequent increase is profits. A lack of definite plane for laying out mine workings is one of the contributory factors to unnecessarily high costs. Although this paper deals primarily with the influence of level spacing on mining costs, still other phases of mine development, such as the proper spacing of ore chutes and raises, can be analyzed on a cost basis in a similar manner, as shown herein. LEVEL SPACING The problem of establishing a new level or levels in order to exploit steeply dioping ore deposits and prospect the ground at depth recurs at intervals during the active life of mines. Driving levels is largely "dead work" and therefore costly. By the judicious selection of the proper level interval after balancing the opposing factors involved in the problem, a considerable saving in mining costs can be effected. Although much has been written in regard to the various methods employed in ore extraction, mining literature is still incomplete in regard to the factors-influencing level spacing at various mines. Level spacing involves procedures not lending themselves readily to description, and, moreover, it is a phase of mining operations that is apt to escape criticism, because only those in close contact with the operations are equipped with the necessary familiarity with the conditions to pass judgment.

Jan 1, 1932

By Edwin C. Reeder

This paper, describing milling methods and costs at the Hillside Fluorspar Mines at Rosiclare, Ill., is one of a series being prepared for and published by the United States Bureau of Mines on non-metallic milling methods. The milling practice described is that of one of the large mines in the Kentucky-Illinois fluorspar field in southern Illinois and western Kentucky, on the Ohio River. Milling methods throughout the district are similar in their general principles, although details vary considerably in different plants.

Jan 1, 1932