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By Peter L. Swanson

This investigation, which began 90 minutes after the February 3, 1995, seismic event, has benefitted from the assistance of a large number of individuals. These individuals provided information, data, analysis, brainstorming opportunities, field equipment, assistance with communication, conducted rock mechanics tests, and provided insight into mining in the southwestern Wyoming trona district. They include Rich Hodgson, Ron Hughes, Larry Refsdal. Mike Weller, John Kolesar, Joe Vendetti, and Rick Casey (Solvay Minerals), Dave Delling (Solvay consultant - former Solvay President), Karl Zipf (formerly with USBM, now with MSHA), Bob Friend, Bob Ferriter, Dave Ropchan, Jerry Davidson (MSHA Tech Support), Don Stauffenberg, Ben Hohler (Wyoming State Mine Inspector's office), Bruce Presgrave (USGS/NEIC), Chris Wood, Dan O'Connell (Bureau of Reclamation), Sue Nava, Jim Pechmann (University of Utah), John Norgord and members of FMC's mine rescue team (FMC Corp.), Bill Walter (Lawrence Livermore National Laboratory), Ron Gerlick, Kevin Wood, and Mike Harmel (USBM rock mechanics lab), Jim Case (Wyoming State Geological Survey), and Solvay consultants. In addition, many individuals helped us gather information on other recent large mining-related seismic events in Germany, Russia, and Australia. and other parts of the United States. These individuals include Wolfgang Minkley (IfG Institut fur Gebirgsmechanik, Leipzig), Arnfinn Prugger (Potash Corp. of Saskatchewan), Hartmut Spetzler (University of Colorado/ University of Bayreuth), Sergei Stanchits (Ioffe Poly-technical Institute, St. Petersburg), Rocky Thompson (Cyprus-Amax) and numerous seismologists throughout the Internet.

Jan 1, 2011

By R. L. Handy

The objective of this research was to devise and test an apparatus to rapidly evaluate the cohesive and frictional strength of coal in situ, in order to increase the safety and percentage of coal recovery from underground coal mines. During the first year device was designed utilizing the bore-hole shear test principle from soil shear strength testing: Two opposing corrugated plates are forced outward to exert a controlled contact pressure against the sides of a previously bared hole, and then the plates are very slowly pulled along the axis of the hole to cause shearing of coal in contact with the plates. Results with the device are expressed in terms of a friction angle[_] and a cohesion c. The [ ] angles obtained from an Iowa coal arc in close agreement with and fall between results from triaxial and direct shear laboratory tests on the same coal. The measured cohesion was found to be much less than from the comparable laboratory tests. It may be increased by pre-stressing and other techniques to embed the shear plate teeth for the first shear test point.

Jan 1, 1973

By F. S. Wartman

Recent changes in metallurgical practice, particularly those in flotation, have altered greatly the functions of the different units of a copper smelter. Gangue minerals are removed from the feed so much more thoroughly that the reverberatory furnace, once virtually a concentrator in which a low-grade ore was concentrated into a rich matte by virtue of the removal of gangue elements as slag, has become very largely a melting furnace in which the rich flotation concentrates are rendered molten so that they may be converted. Moreover, since the proportion of matte to slag in the reverberatory furnace output is greater than it was formerly, the amount of converter slag returned to the reverberatory for cleaning is, in comparison to the amount of slag actually formed in that furnace, also much larger. In some cases, approximately half of the reverberatory dump slag may have originated in the converter. The increase in the proportion of convertor slag to total slag produced has brought about certain consequences not entirely desirable. Converter slags contain a high percentage of iron and therefore are high in specific gravity and are very basic. A considerable guantity of magnetite, both dissolved and suspended as solid crystals, is always a component, The basic nature of the ordinary converter slag and the presence of the suspended magnetite crystals make impossible the reduction of the copper content of the slag below approximately 1 per cent by even the most prelonged settling, and a re-treating process is necessary. At present, general practice in western copper smelters is to return the converter slag molten to the reverberatory furnace. Here dilution by mixing, with slag formed in the reverberatory furnace and reaction with raw sulphides and siliceous materials in the reverberatory feed reduce the magnetite and increase the silicates to the point necessary for a satisfactory dump slag.

Jan 1, 1930

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

By G. S. Baur, J. W. Montoya, S. R. Wilson

Beryllium occurs in the Honeycomb Hills area in volcanic tuff similar to the more extensive berylliferous tuff occurring 20 miles east at Spor Mountain , Juab County , Utah . Samples from the two areas have been mineralogically examined to ascertain whether they have similar characteristics . The Honeycomb Hills samples showed the presence of beta- Be ( OH ) 2 , as well as an amorphous berylliferous substance , whereas in the Spor Mountain tuff the beryllium- bearing minerals are hydrated bertrandite and berylliferous saponite .

Jan 1, 1964

By W. H. King

"INTRODUCTION The manganese deposits of the Drum Mountain area were investigated as two separate projects. The first was begun in November 1940 and completed in August 1941, and the second began in January 1945 and ended in May of the same year. The first project was initiated as part of the Bureau of Mines program for development of strategic minerals for national defense. Subsequent operations disclosed conditions somewhat different than were expected, and it was decided that additional drilling should be done to delimit the ore bearing horizons further.The more promising manganese deposits in the Drum Mountains are situated on properties known as the Staats manganese mine and the Pratt manganese mine. The property controlled by the Pratt interests is under lease to the Ward Leasing Co. The 1941 project investigated the deposits on both properties, whereas the 1945 project was planned to explore further the oxidized ore bodies of the Pratt mine, although one hole was drilled in an attempt to extend the carbonate ore body on the Staats property (fig. 1).ACKNOWLEDGMENTSIn its program 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 preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

Jan 1, 1947

By G. St. J. Perrott, N. A. Tolch

"The testing of explosives for permissibility for use in coal mines was begun by the technologic branch of the United States Geologic Survey in February, 1909, and continued by the United States Bureau of Mines from July, 1910; this testing has been carried on from year to year as the explosives were submitted by manufacturers. As a result of these many years of testing for permissibility a large amount of data has accumulated regarding the characteristics of permissible explosives. The manufacturer expects a sample of explosive submitted for test to meet the requirements for permissibility, otherwise the sample would not be submitted. However, in spite of the careful regulation and preparation of the formulas a certain percentage of explosives fails to pass the gallery tests. It is therefore interesting to note the proportion of failures at the gallery for a given composition of explosive. The fact should be emphasized that this discussion deals with all explosives submitted for test, both those which passed the tests and those which failed to pass. Explosives that failed to pass the tests were never designated as permissible explosives and have never appeared on any list of explosives permissible for use in coal mines.The Bureau of Mines classifies permissible explosives in two ways, according to the quantity of poisonous gases produced and according to the characteristic ingredient of the explosive.4 In this paper only two types of the latter classification are considered, as follows:"

Dec 1, 1929

By D. W. Frommer

As one phase of a general problem of recovering sulfide slimes, mineral-dressing research was conducted on flotation tailing from the St. Joseph Lead Co., Bonne Terre, Mo., mill to recover a significant portion of the residual, finely divided galena. Production of a high-grade concentrate was not part of the immediate objective. Only a reasonable ratio of concentration of lead sulfide slime was sought, since the problem of upgrading by mechanical or extractive processes would be considered in the later stages of this study. The results show that, from a feed material averaging 0.20 percent lead (about 70 percent finer than 400-mesh), a recovery of up to 45 percent could be effected by flotation in rougher concentrate analyzing up to 6.5 percent Pb. These results were obtained by using larger quantities of various xanthates and sodium sulfide than used customarily in mills. Sodium sulfide, which is ordinarily detrimental to flotation of galena, was beneficial in this case.

Jan 1, 1959

By Walter W. Fisher

Cement copper was flash roasted in a vertical tube furnace to convert the copper to acid-soluble oxides as part of a postulated process for refining cement copper by oxidation roasting, acid leaching, and electrowinning. The results of the study showed that the oxidation was a linear function of oxygen concentration between 0 and 20 percent, but above 20 percent oxygen there was no further increase in oxidation. Therefore, air was the optimum oxidizing atmosphere in this flash roasting system. The oxidation followed a parabolic rate law as the roasting temperature was increased from 400° to 800° C. Extrapolation of the data, based on the parabolic law, indicated that at 400°, 500°,600°,700°, and 800° C, the roasting times required for complete conversion to soluble oxides were 75, 37, 21, 7.7, and 4.6 seconds, respectively. Cyclic-roasting test results did not substantiate the predictions obtained through data extrapolation.

Jan 1, 1973

By Timothy A. Clancy

In support of research on forming ceramics from mining and processing wastes, the Bureau of Mines tested various commercial refractories to evaluate their resistance to melts of these wastes. Sixteen refractories of various types were exposed in slag erosion tests to two siliceous waste melts with Si02/CaO ratios of 4.0 and 2.2, The extent and nature of slag attack were then determined for each refractory. The nature of slag attack was investigated through scanning electron micrographs and microprobe elemental distributions. The refractories that performed best in resisting attack by the melts were high-alumina types, and of the refractories tested, the most resistant was a 90-pct-Al203, 10-pct-Cr203 refractory.

Jan 1, 1983

By W. W. Adams

"The present world-wide demand for increased production in all branches of essential industry involves a matter of vital concern t persons engaged in the mining industry, namely, the productive capacity of the individual mine employee. This applies particularly to coal-mining, upon which other industries so largely depend.The folded and faulted condition of the coal beds in some countries, as well as the thinness and depth of the seams, the adaptability to the beds of available mining machines and equipment are factors which cannot be overlooked in determining what increase in individual output may be looked for in any given country. This subject, while of fundamental importance, can only be referred to in a paper of this length, the primary object here being merely to present a comparative tatamant of individual output under prevailing conditions.The quantity of coal produced by a miner does not accurately indicate the miner's capacity as a workman, not only because of the natural conditions referred to above that limit his annual output, but also because of human factors which may possibly, however, be controlled, such as the demand for coal, the car supply, use of labor-saving machinery, number of days worked during the year, accidents in the mine, etc. It will, however, be an aid in answering the important question as to how and where the immediate need for coal throughout the world may best be surlier, if we examine the output of the miners in the important coal-producing countries over a period of years.Complete official information for recent years is, for several countries, jacking, particularly for France, Austria, and Prussia, but partial data from unofficial sources may be used to show the individual output of the miners in these countries."

Jul 1, 1920

By M. M. Tilman

The objectives of this research were to determine the practicability of using cobalt as a means of controlling the amount of ferrite in the micro-structures of semiaustenitic stainless steels, and to determine the effects of reduced ferrite content on mechanical properties of these steels. Cobalt additions of up to 3 weight-percent were made to type 17-7 PH2 (AISI 631) stainless steel. Ferrite contents were determined for alloys in the aged condition, and for alloys quenched from the hot working temperature. Ferrite can be completely eliminated from the microstructure of 17-7 PH stainless steel by additions of cobalt, but complete elimination of the ferrite phase results in lower tensile strength, yield strength, and hardness. Tensile properties, hardness, and impact strength were determined for aged material. A subzero temperature treatment before heattreating was necessary to obtain maximum strength in the alloys containing cobalt. Addition of 2 weight-percent cobalt enhances mechanical properties of 17-7 PH stainless steel.

Jan 1, 1968

Provide the technology to remotely control a thin¬-seam continuous mining machine from a safe location hundreds of feet outby the working face in an underground room-and-pillar mine. Background and Approach Hard-wired or radio remote control of continuous mining machine has been commercially available since the early 1970's. This type of remote control, in low and high coal seams, situates the machine operator offboard, but within direct view of the underground coal face, Although positioned under supported roof, the operator can still be exposed to face area hazards that include roof-rib falls, dust, methane explosions, and equipment congestion. The U.S. Bureau of Mines approach has been to put the operator into a protected compartment at a location away from the working face. Since 1979, the Bureau has investigated innovative methods to better protect face area workers in under¬ground room-and-pillar mines. In 1989, the Bureau demonstrated an offboard, computer-based remote con¬trol system in a West Virginia highwall mining operation that stationed the operator hundreds of feet away from the working face. In late 1992, much of this technology, plus improvements, Was used to demonstrate, on the surface, how a thin-scam continuous mining machine could be remotely controlled 200 feet from the machine in a 36-inch working height.

Jan 1, 1992

By Douglas C. Corner

This is the first of a series of papers dealing with modern tunnel-driving methods, compiled in accordance with an outline prepared by engineers of the United States Bureau of Mines and to be published in a series of information circulars by the bureau. This series will supplement a similar and earlier series of papers dealing with mining methods and costs. ACKNOWLEDGMENTS The author desires to express hiss appreciation, of the assistance of A. C. Dennis, manager for the West Construction Co. Contractors, and Franc: E. Winsor, chief engineer for the Boston Metropolitan District mater Supply Commission who furnished much of the data and detailed description of operation appearing in the following pages. C. F, Jackson, mining engineer, United States Bureau of Mines, collaborated in the preparation and arrangement of the text.

Jan 1, 1931

By R. L. Stein

For the past several years, the Bureau of Mines has been actively engaged in developing two new oxygen self-rescuers through research contracts with private industry. These new oxygen self-rescuers are designed to be carried by a miner while he is at work and are used during emergency escape, supplying high-purity oxygen to the user and, at the same time, absorbing carbon dioxide (C02), The first of the two new self-rescue breathing devices is a 10-minute, self-contained apparatus developed by the Mine Safety Appliance Co, Size and weight of the unit are comparable to the currently used self-rescue devices. The second device, designed and developed by Lockheed Missiles and Space Corp., is 8. 4.5-lb package which supplies 1 hour of oxygen to the miner. Both devices have a canister which contains the oxygen-producing and CO2-absorbing potassium superoxide chemical, a breathing bag, a bite-type mouthpiece, noseclip, goggles, and hoses connecting the canister and mouthpiece. When needed in an emergency, the miner removes the outer protective cover and dons the unit. For both devices oxygen is immediately available once the mouthpiece is placed in the mouth. These two new units have received prototype approval from the National Institute for Occupation and Safety Health (NIOSH) and the Mining Enforcement and Safety Administration (MESA).

Jan 1, 1976

1. In 2002, a total of 4,311 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). The major industrial classifications in stone mining are dimension stone (used for construction purposes), crushed and broken stone (aggregates), cement, and lime. Stone mines comprised 29.7% of all mining operations. • Mines producing crushed and broken stone (n = 3,372) comprised 78.2% of all stone mining operations.

Jan 1, 2004

By E. J. Murphy

The Bureau of Mines developed a fast, reliable modification of the Griess-Ilosvay procedure suitable for field analysis for NO2 in the fumes from explosives. Known concentrations of NO2-air mixtures were analyzed for the nitrous acid or nitrite formed in the reaction with three Griess-Ilosvay-type reagents by diazotizing and coupling. Comparison was made of the Rider-Mellon, Saltzman, and Patty-Petty procedures; the three procedures are in agreement if sufficient time of contact between NO2 and the reagents is allowed. In experiments to obtain an accurate factor for converting NO2 to nitrite, overnight contact was allowed in order to be sure conversion was complete. The factor was found to be 75 percent with a standard deviation of ±3.2. Low and erratic results were found using either the Saltzman or Patty-Petty reagents as absorbing liquids unless several hours' contact was allowed. If dilute NaOH solution was used as the absorbing liquid instead of a Griess-Ilosvay-type reagent, 92 percent of the overnight conversion factor was found after a 3-minute shaking time and a la-minute standby time. The Saltzman reagent was preferable for fieldwork with the dilute NaOH solution as the absorbent because of its easy application, rapid reaction, and intense color even at low NOB concentrations.

Jan 1, 1967

By Gerald V. Gibbs

As a part of the Bureau of Mines long-range program in asbestos, synthetic asbestiform compounds and minerals were prepared and described. Fundamental structural data on two such compounds are given in this report. Crystallographic data are provided for the synthetic isotypic compounds potassium-lead silicate, K2.Pb4 -Si8021 (I), and lead-aluminum silicate, Pb2. Pb4 .Al2Si6O21 (II). The space group symmetry 14/mmm was assigned provisionally to I and II on evidence of single crystal and piezoelectric measurements. A statistical evalua¬tion of indexed powder diffraction data revealed the cell edtes of I to be a 11.816 and c 7.932A and those of II to be a 11.723 and c 8.044A. The phases are uniaxial with observed refractive indices eD 1.790, an ?D,699 and eD 1.884, cusp 1,807, respectively. The atomic structure of I and II may be based on a complex of chains of silicon-oxygen tetrahedra lying along the c cell edge similar to the type of chain structure postulated by Pauling for scapolite. K2.Pb4.Si8021 and Pb2.Pb4 Al2Si6021 were first described by Geller and Bunting (5, 6)4 as fibrous compounds similar in crystal habit to asbestos. These authors gave powder diffraction data, although no attempt was made to find the cell edges or to index the powder diffraction patterns. Later, Shell and others (9) conducted a crystallochemical study of these fibrous silicates in search of a substitute for strategic asbestos. Their single crystal data revealed K2.Pb4 -Si8021 to be tetragonal body-centered with cell edges a 11.66, c 7.95 A. Pb2.Pb4 Al2Si6021 was concluded to be isotypic with K2.Pb4 -Si8021 on the basis of similar powder diffraction patterns, chemistry, and physical properties. No attempt was made, however, to index the powder diffraction record nor to determine the appropriate space group of either compound.

Jan 1, 1962

By Wilbur I. Duvall

A linear array of shot and gage holes 30 feet deep in a granite outcrop was used to compare the size and shape of radial strain pulses produced in the rock when short cylindrical charges of cast composition B were detonated axially or at one end. The axially detonated charges produced radial strain pulses that had shorter rise times and larger peak strain than the strain pulses produced by end detonated charges.

Jan 1, 1965

By E. R. Cole

A lead smelting process that appears to present minimal pollution problems has been developed at the Bureau of Mines, Rolla Metallurgy Research Center. Ten and 100 g samples of PbS mill concentrates were vaporized at 1,000° to 1,100° C in a furnace with an inert gas atmosphere during a 2-hour period. The PbS vapor was transported by the inert carrier gas to the reduction zone of the furnace where it was reduced at the same temperature with excess hydrogen to metallic lead. Lead of 99.9 pct purity was produced. The H2S formed can be decomposed into elemental sulfur and water vapor by a modified Claus process. Approximately 90 pet of the Cu and 70 pct of the Ag and Zn remain in the residue and are potentially recoverable. More than 98 pct of the lead in the concentrates was extracted.

Jan 1, 1974