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By L. C. IlsLey

It is most unfortunate that a few must often suffer , and perhaps die , that many may benefit from a fuller appreciation of the dangers surrounding mining operations , and the proper use of safeguards designed to offset these dangers . This has been the case during the last few months in the anthracite field , where several explosions , resulting in burnings and fatalities , were undoubtedly caused by the use of defective or improperly assembled flame safety lamps . Had this same lack of understanding regarding the proper assembly of this safety device , and had the same indifference on the part of the user in keeping the lamps locked at all times and in proper condition , been permitted in a region where the coal dust was explosive , a terrible disaster would surely have resulted . In nearly every coal -mining country , including the United States , the Davy and Clanny type of lamp has been superseded , and rightly so , by some kind of bonneted lamp . Bonneted lamps , especially of the naphtha type , while much safer than the unbonneted , have more parts and need more care in assembling . For this reason the burden of responsibility for their being properly assembled rests with the lamp man ; therefore , it is extremely important that only competent , conscientious men be given this work .

Dec 1, 1921

By Fred N. Kissell, J. E. Matta, J. C. LaScola

The Bureau of Mines made laboratory absorption measurements on oil shale samples, which showed that the amount of methane absorbed is proportional to pressure and oil yield, and can be much larger than would be predicted based solely on porosity. Oil shale cores collected in the field were also measured for their gas content using the Bureau of Mines direct method, Cores taken from deep locations and far from outcrops yielded more gas than cores from shallower locations or at outcrops, when taking into account variations in oil yield, and all data indicate that oil shale mines that are both deep and far from an out- crop will emit low levels of methane gas.

Jan 1, 1977

By Robert S. Sanford

The Broughton and Ring magnetite deposits in Essex County, N. Y., are thought to be in a mineralized belt that extends from the Lake Sanford mining district to Lake Champlain and passes through the Mineville district. The country rook is syenite-gneiss, similar to that in the Mineville area. The Bureau of Mines conducted a vertical magnetometer survey of the area. On the Broughton properties there are no indications, magnetically, of magnetite in any degree of concentration. 'On the ding properties a number of sharp, localized magnetic anomalies were observed. One core-drill hole was bored to a, depth of 48.3 feet, also, to test one of the strongest anomalies. The field work was in progress from December 1943 to July 1944. Although no iron ore was intersected by' the drill hole, it showed that the amphibolite rook, at a depth of 6 to 100 feet below the surface, contained enough magnetite and iron sulfides to account for the anomalies recorded by the magnetometer survey.

Jan 1, 1949

By M. M. Tilman

The Bureau of Mines conducted research to evaluate superplastic behavior in commercial magnesium-base alloys AZ6IA, ZK60A, ZW3, AZ3IB, ZWI, and an experimental Mg-12 pct Al alloy. Strain-rate sensitivity indices (m-values), maximum elongations, and effects of superplastic elongation on tensile properties were determined on fine-grained sheet. Inert-gas-pressure hemisphere-forming tests were conducted on selected sheet stock of the five alloys. Formability trials on AZ31B alloy sheet were conducted on industrial equipment for comparison with commercial superplastic forming of Zn-AI alloy. Closed-die-forming tests were performed on extruded ZK60A rod. All alloys exhibited well over 100-pct elongation, indicating superplasticity, at temperatures and strain rates near the maximum m-values. Tensile properties were generally reduced following 100-pct superplastic elongation, but not to an extent that would preclude use of the commercial alloys in the superplastically deformed condition. The potential for industrial superplastic forming of AZ31B sheet was indicated by hemisphere forming in the laboratory and substantiated in industrial forming trials.

Jan 1, 1982

By J. W. Walkiewicz

One of the objectives of the Bureau of Mines is to develop substitution technology for scarce materials. In accordance with this goal, alloys containing lanthanum, cobalt, copper, and magnesium were investigated for fabrication of rare-earth-cobalt (RE-Co) permanent magnets. A complete substitution of lanthanum for samarium and a partial substitution of copper for cobalt was accomplished. Magnets of La-Co and La-Co-Cu-Mg alloys were fabricated by powder metallurgy techniques and evaluated. A maximum intrinsic coercivity of 23.2 kOe was obtained with a La-Co-Cu-Mg alloy. In comparison, maximum values of 9.3 kOe and 11.6 kOe were obtained with La-Co and La-Co-Cu alloys, respectively. The substitution of copper and magnesium for part of the cobalt resulted in a large increase of intrinsic coercivity, similar to the results of Bureau research with mischmetal-Co-Cu-Mg alloys. Unlike the mischmetal-Co-Cu-Mg magnets, the La-Co-Cu-Mg magnets showed signs of physical deterioration on exposure to air. The effects of fabrication parameters on the magnetic properties of the La-Co-Cu-Mg alloys were also determined.

Jan 1, 1982

By Charles H. Shapiro

[In July, 1924, the Bureau of Mines, through its Petroleum Experiment Station, undertook a field study of methods used in oil-field shops for dressing and tempering fishtail bits. The purpose of this work was to suggest chances that would be helpful to the bit-dresser in turning out better treated, harder, and tougher bits, and thus cut down the excessive loss of time caused by too frequent changing of bits. It was the intention to eliminate as much as possible the guess work connected with dressing and tempering bits under the method of judging temperature by eye, by developing; practical methods of controlling temperature. If there were some possible means of accurate temperature control, then it would be an easy matter to bring all bits to the proper temperature for maximum hardness rued toughness, thus doing away with the source of most of the trouble experienced in the present method of bit tempering. Shortly after the Bureau of Mines began its study, a chop In the Stroud, Oklahoma, oil field announced method for tempering fishtail bits that Would increase the drilling footage of each bit treated. The method accurately regulates, by the use of a bath of molten salt, the temperature to which a bit is heated before being quenched to produce hardness. There is nothing new in using silt baths for the, heat treatment of steel, but this was the first attempt to introduce it into the oil fields for use in hardening bits, and for this purpose it proved to be admirably adapted. In tempering, by the old system it is not possible to measure the temperature of the heated bit by means of an electrical instrument for that purpose, whereas this is an easy matter with the now method. If heating steel to slightly above the critical point rind quenching suddenly will bring out its best properties, their here is a method of accurately bringing the steel to that point.]

Jan 1, 1925

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall employment and injury experience for coal mines-bituminous, lignite, and anthracite; coke, petroleum and natural gas; and peat and slag plants; metal and nonmetal mines; sand and gravel operations; stone quarries; metallurgical plants, including metal mills and smelters; and nonmetal mills for 1959. Volume I of the yearbook contains injury experience and employment data in the metal, non-metal, sand and gravel, slag, and quarrying industries, and the milling operations and related plants. Volume II contains the injury experience and employment data in the fuel industries--coal, coke, petroleum and natural gas, and peat. Surveys conducted by the Bureau of Mines were the source of injury and employment data used to compile the tables and furnish information for the accompanying text. Response to the surveys was voluntary except that for coal mines. The Coal Mine Safety Act requires operators of coal mines to furnish the information requested.

Jan 1, 1960

By Noel N. Moebs

The Bureau of Mines measured surface subsidence above four small coal mine room-and-pillar sections in southwestern Pennsylvania, to obtain preliminary information on the magnitude and character of selected parameters, such as angle of draw and maximum subsidence, which are essential to the development of subsidence prediction methods. Data varied widely at the four sites; this is attributed to local geologic and mining conditions. Surface deformation at each site was of a magnitude normally associated with severe structural damage.

Jan 1, 1982

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds of Beaver and Lawrence Counties, Pa. Washability analyses were made on seven coalbed samples, none of which were of metallurgical quality as received. Five of the samples could be sufficiently upgraded to produce acceptable products, and the remaining two samples could not be upgraded to metallurgical quality because their sulfur contents could not be lowered to meet the standard. For steam or power generation, one sample was of low sulfur content as received, one sample could be upgraded to low sulfur content, and three samples could be upgraded to medium sulfur content. The original sulfur content of the remaining two samples can be appreciably reduced by removal of the sink 1.58 speci fic gravity material; however, these coals would be classified as medium sulfur coals both before and after removal of the sink material.

Jan 1, 1969

By S. L. Payne, E. F. Foerster, C. W. Schultz, G. R. Zellars

The vapor pressure of copper in a series of liquid copper - nickel alloys was determined by the carrier gas method . The activity and activity coefficient of copper were calculated over the entire range of alloy composition . These data show a slight positive deviation from ideal behavior . The activity coefficient of copper was highest ( 2.10 ) at 0.05 mole fraction copper and approached unity at concentrations above 0.85 mole fraction copper . The results for nickel were calculated from the copper data by the graphical integration of the Gibbs - Duhem equation .

Jan 1, 1964

By T. A. Sullivan

Research undertaken by the Bureau of Mines in 1938 has resulted in the development of titanium from a laboratory curiosity to a commercial metal. Along with processes for producing the metal, it was necessary for the Bureau to develop methods for analyzing the metal, raw materials, and intermediate products. Some of the methods developed have been published.3 4 5/ General Services Administration (GSA) was responsible for purchasing titanium metal under Defense Production Act contracts with commercial producers. GSA designated the Federal Bureau of Mines to analyze this metal and establish its compliance with Government specifications. A substantial quantity of tin was found in some of the samples analyzed, and in July 1957 tin was added to the list of impurity elements to be determined. The specifications limited the amount of tin in titanium sponge to a maximum of 0.10 percent. A program was immediately initiated to investigate methods and techniques for determining tin in the range of 0 to 1.0 percent. A method accurate at the 0.10 percent level was necessary, as this level was the critical range for acceptance or rejection of the metal.

Jan 1, 1960

By E. G. Valdez

The Federal Bureau of Mines, in cooperation with Ford Motor Co., investigated the recovery of polyurethane foam and other assorted plastics from the nonmagnetic reject of automobile shredders. Preliminary studies were con-ducted on a 1957 hulk augmented with additional foam and assorted plastics. The proposed flowsheet developed by the Bureau from the preliminary studies consists of a combination of screening, water classification, and gravity separation. The process was then tested on reject from two shredded 1972 cars. All of the foam and between 52 and 70 pct of the assorted plastics were recovered. The composition of the reclaimed foam concentrates ranged from 46 to 66 pct foam; the concentrates were hydrolyzed in laboratory tests by Ford Motor Co. to produce a reusable liquid mixture of polyether glycol monomers and toluene diamine.

Jan 1, 1975

By Robert P. Vinson

A sequential sampler, based on the Archimedes screw, has been developed by the Bureau of Mines. Its initial purpose was to collect air samples during tracer gas studies in underground mines. However, the basic concept can be applied to other sampling needs, including sampling of liquids. A prototype was built and successfully tested in the Bureau's Experimental Mine at Bruceton, Pa. The simple design makes the sampler inherently durable and low in cost.

Jan 1, 1976

Develop technology for preparing thick corrosion-resistant coatings and electroforms of iron-chromium-nickel alloys. Approach To reduce the United States' dependence upon foreign sources for supplies of strategic and critical metals such as chromium, cobalt, and nickel, new technology must be devised to conserve these valuable commodities. One approach being investigated by the Bureau of Mines is the use of a modified-aqueous-electrodeposition method to prepare thick (-25 µm), complex alloy coatings (e.g., stainless steel composition) with properties similar to the commercial alloys. An alloy coating on a low-alloy steel or carbon steel substrate would require significantly less strategic and critical metals than those contained in an equivalent mass of the commercial alloy. Coatings applied to appropriate mandrel materials make possible the preparation of intricately-shaped alloy electroforms (near-net-shape parts). As a result, the loss of valuable metals associated with machining finished products would be minimized.

Jan 1, 1986

By E. G. King

The work described in this Bureau of Mines report was undertaken to fill a need of industry for high-temperature heat-content data for uranium tetrafluoride. Without such data, heat balance evaluations of processes involving this substance are seriously hampered. Measurements of the heat content of uranium tetrafluoride were conducted at temperatures from 298° to 1,350° K. The melting point and heat of fusion were determined. The results are presented in suitable tabular form, and representative heat-content equations are included.

Jan 1, 1961

By A. T. Iannacchione

Designing coal pillars to provide resistance against overburden and gob loads has long been an aim of rock mechanics engineers. This requirement has become more imperative as greater overburdens are encountered and when mining in stiff coal-bearing strata. Current design procedures rely on theories of coal pillar behavior that take into consideration a common hypothesis. This hypothesis states that the elastic core is surrounded by an inelastic yield zone. The distribution of stress at low-to-moderate pillar loads has been effectively defined by this hypothesis. However, it suffers greatly when applied to large width-to-height (w/h >lo) coal pillars under considerable overburden (>500 m) . In these situations, the hypothesis says the elastic core can achieve unrealistic stress states giving the pillars extremely high calculated strength. A growing body of field studies has shown this is not the case. It has become clear that same other mechanism must be involved. It is the purpose of this paper to discuss the importance of an interface slip mechanism between the coal- bed and the surrounding strata in controlling the extent and pattern of stresses and deformations in a coal pillar.

By J. N. Van Sant

Lignite mining in North Dakota was begun about 1884 to supply the domestic needs of settlers. Annual production has grown rather slowly but steadily, exceeding 3 million tons in 1950. The western part of the State has lignite reserves, amounting to 351 billion tons, underlying an area of 28,000 square miles. Contour strip mining has almost completely replaced underground mining as the method of production. Lignite is often found under rather shallow and easily removed overburden, and this is the primary reason for the change in mining practice. Current mining operations are conducted where the overburden is 30 to 70 feet thick. Contour strip mining results in high production rates, at present 27 to 56 tons per man-day. These high production rates result in relatively low production costs.

Jan 1, 1959

By Kris Chatrathi, John E. Going, Kenneth L. Cashdollar

Two types of flammability limits have been measured for various dusts in the Fike 1-m3 (1000-L) chamber and in the Pittsburgh Research Laboratory (PRL) 20-L chamber. The first limit is the minimum explosible concentration (MEC), which was measured at several ignition energies. In addition to the three dusts studied previously (bituminous coal, anthracite coal, and gilsonite), this work continues the effort by adding three additional dusts: RoRo93, lycopodium, and iron powder. These materials were chosen to extend the testing to non-coal materials as well as to a metallic dust. The new MEC data corroborate the previous observations that very strong ignitors can overdrive the ignition in the smaller 20-L chamber. Recommendations are given in regard to appropriate ignition energies to be used in the two chambers. The study also considered the other limiting component, oxygen. Limiting oxygen concentration (LOC) testing was performed in the same 20-L and 1-m3 vessels for gilsonite, bituminous coal, RoRo93, and aluminum dusts. The objective was to establish the protocol for testing at different volumes. A limited investigation was made into overdriving in the 20-L vessel. The LOC results tended to show slightly lower results for the smaller test volume. The results indicated that overdriving could occur and that ignition energies of 2.5 kJ in the 20-L vessel would yield comparable results to those in the 1- m3 vessel using 10.0 kJ. The studies also illustrate the importance of dust concentration on LOC determinations.

By Motohisa Kanda

The time and amplitude statistics necessary to adequately describe electromagnetic (EM) noise in mines are illustrated through computer software techniques. They are 1) Allan Variance Analyses (AVA), 2) Interpulse Spacing Distributions (ISD), 3) Pulse Duration Distributions (PDD), 4) Average Crossing Rates (ACR) , and 5) Amplitude Probability Distributions (APD) . These statistics are illustrated using data taken from a rather large store of raw analog data recorded in operational mines. The curves generated for the illustrations characterize the noise environment in the mines from which the corresponding data were taken, and should aid in the design of reliable communication systems for such mines.

By B. K. Cantrell, K. L. Rubow

"Two source apportionment techniques have been applied by the Bureau of Mines to aerosol measurements in diesel equipped underground noncoal mines. The first technique is based on size selective sampling and the premise that the diesel exhaust fraction of the aerosol is predominately sub-micron in size while the mineral dust fraction of the aerosol is mostly super-micron in size. The second technique, Chemical Mass Balance (CMB) modeling, was used to referee the analysis of diesel and mineral dust aerosol concentrations with the size selective method.The size distribution data were modeled using a log-normal regression to parameterize the sub- and super-micron fractions of the sampled aerosol and to estimate the mineral and diesel contributions to each. For the mines visited, analysis of the size selective: samples yielded an average value for the fraction of the fine aerosol attributable.to mineral dust of 3 pct.'The CMB analysis, applied to both fractions of the respirable mine aerosol, yielded the amount contributed to each by the diesel· and dust aerosol sources. Less than 5 pct of the sub-microm fraction was mineral dust, however, as much as 20 pct of the diesel aerosol was found: ""in the super-micron fraction requiring a correction of the sub-micron fraction to account for the missing diesel mass. More accurate measurement will require a carbon specific analysis of the aerosol."

Jan 1, 1988