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By W. N. Marchant

The Bureau of Mines improved removal of selenium from zinc smelter acidic gas scrubber effluent by using zinc dust to precipitate soluble selenium prior to lime neutralization. Lime neutralization alone decreased selenium in the waste water from, typically, 6 parts per million to 2 parts per million, whereas the use of zinc dust precipitant gave an effluent containing less than 0.1 part per million of selenium. The waste treatment operation first was developed on a laboratory scale and later was successfully tested at a smelter site on a 1-gallon-per-minute basis. During the research a simple and rapid means was developed for determining selenium in waste water; the technique enabled visual semiquantitative selenium determinations that later were confirmed quantitatively by X-ray fluorescence.

Jan 1, 1978

By John J. Sammarco

This report (System Safety Guidance 5.1) is the sixth in a nine-part series of recommendations and guidance addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans, and the operating environment for the equipment’s life cycle. Figure 1 shows a safety framework containing these recommendations. The reports in this series address the various lifecycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended for use by mining companies, original equipment manufacturers, and aftermarket suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. • 1.0 Safety Introduction (Part 1).—This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics (PE), and includes the benefits of implementing system/software safety program. • 2.1 System Safety (Part 2) and 2.2 Software Safety (Part 3).—These reports draw heavily from International Electrotechnical Commission (IEC) standard IEC 61508 [IEC 1998a,b,c,d,e,f,g]and other standards. The scope is “surface and underground safety-related mining systems employing embedded, networked, and nonnetworked programmable electronics.” System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the system’s safety. • 3.0 Safety File (Part 4).—This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system’s use and operation. In essence, it is a “proof of safety” that the system and its operation meet the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full life cycle of the system, and provides administrative support for the safety program of the full system. • 4.0 Safety Assessment (Part 5).—The independent assessment of the safety file is addressed. It establishes consistent methods to determine the completeness and suitability of safety evidence and justifications. This assessment could be conducted by an independent third party. • Safety Framework Guidance.—It is intended to supplement the safety framework reports with guidance providing users with additional information. The purpose is to assist users in applying the concepts presented. In other words, the safety framework is what needs to be done and the guidance is how it can be done. The guidance information reinforces the concepts, describes various methodologies that can be used, and gives examples and references. It also gives information on the benefits and drawbacks of various methodologies. The guidance reports are not intended to promote a single methodology or to be an exhaustive treatment of the subject material. They provide information and references so that the user can more intelligently choose and implement the appropriate methodologies given the user’s application and capabilities. The guidance reports comprise parts 6 through 9 of the series and are listed below: [< 5.1 System Safety Guidance (Part 6).—This guidance supplements 2.1 System Safety. < 5.2 Software Safety Guidance (Part 7).—This guidance supplements 2.2 Software Safety. < 6.0 Safety File Guidance (Part 8).—This guidance supplements 3.0 Safety File. < 7.0 Independent Functional Safety Assessment Guidance (Part 9).—This guidance supplements 4.0 Independent Functional Safety Assessment.] [ ]

Jan 8, 2005

By P. D. Bergman

To assess the efficacy and economics of producing power from coal, four open-cycle magnetohydrodynamic (MHD) processing schemes were selected for study. Each involved a different mode of coal combustion and level of gas cleanliness. The options considered were: (1) coal burned in a slagging combustor; (2) suspension gasification with slag removal prior to combustion; (3) parallel cyclone combustors, one operating fuel rich and the other operating with excess air; and (4) suspension gasification by the hot exhaust gases from the MHO duct with ash removed prior to combustion. Option 1 has the highest ash content in the combustion plasma and as a result would have the greatest operational difficulties associated with it. Options 2 and 4 have the cleanest MHD combustion plasma. For coal priced at $4/ton, the power generating cost of option 4,11.78 mills/Kw-hr, is the highest, with Option 1, at 9.04 mills/kW-hr the lowest. These costs may be compared with a conventional power cost of 9.92 mills/kW-hr for the late seventies. Capital costs of three of the four options were competitive with those of conventional thermal power plants employing stack gas S02 cleanup systems. Option 2 has the most favorable combination of operating characteristics and power cost. It was concluded that a clean, high-temperature working fluid can probably be produced from coal without leading to depressed system efficiencies and exorbitant capital costs.

Jan 1, 1973

By Phyllip Worley, Frank E. Chase, Christopher Mark

The Harris No. 1 Mine, located in Boone County, WV, has been longwalling the Eagle Coalbed for over 30 years. Harris has experienced numerous interactions associated with the extensive room-and-pillar and longwall mining operations which have been conducted in the overlying No. 2 Gas Coalbed. The problems have included roof falls, excessive rib sloughage, and gateroad and bleeder entry closure. A detailed evaluation of the multiple seam experiences at Harris No. 1 Mine was conducted as part of the National Institute for Occupational Safety and Health (NIOSH) nation-wide multiple seam mining case history data base. One observation from the Harris gateroad case histories was that smaller, critically loaded, upper seam pillars seemed to cause more severe ground conditions than did wider pillars. The LaModel program was used to investigate this supposition, and the results confirmed that “critical” sized pillars do transmit the highest amounts of stress to adjacent seams. In addition, the data suggest that the probability of a major multiple seam mining interaction increases when the depth of cover is 1,000 ft or greater and when the Eagle seam pillars have a Analysis of Longwall Pillar stability factor less than 1.50.

By Edward J. Kansa

In a Bureau of Mines study, unsteady, spherically symmetric, one-dimensional, compressible-flow (finite sound speed) equations were solved numerically for a spherical deflagration propagating concentrically in a spherical vessel with Mach numbers ranging from 0.2 to 0.7; trajectory histories agree with the infinite-sound-speed theory developed by Perlee, Fuller, and Saul (PFS). A preliminary result of this study shows that flames propagating with speeds greater than 20 pct the speed of sound in the unburned gas mixture generate a complex history of aerodynamic waves distributed throughout the spherical vessel. Although the average pressure and flame radius agree with those predicted by the PFS models, the aerodynamic waves have a pronounced effect on the flame velocity, differing appreciably from that predicted by the PFS model.

Jan 1, 1976

By Eric E. Cather

A mineral investigation by the U.S. Bureau of Mines revealed no mines or prospects and no past or present mining claims in the Agua Tibia Wilderness Study Area (WSA). The area is underlain mainly by weakly foliated gabbro similar to rock that has hosted gem- and lithium-bearing pegmatites in the Pala district about 6 mi to the south. However, no gem- or lithium-bearing pegmatites have been discovered in the WSA. Nearby quarries in the gabbro have yielded rock for facing and dimension stone. No sand, gravel, or energy (oil, gas, coal, or geothermal) resources were identified.

Jan 1, 1984

By M. D. Schlesinger

Mercury exists in coal at very low levels; the structure of coal, the vapor pressure of mercury, and its almost universal occurrence introduce unusual problems into the analytical methods. Round-robin analyses by several laboratories, each using its own techniques, indicate that the average mercury content of coal is about 0.2 part per million. Some western coals are as low as 0.05 ppm.

Jan 1, 1971

By Constantine C. Popoff

During 1946 several high-grade limestone deposits in western Washington were examined by the Federal Bureau of Mines. The purpose of the examinations was to disclose new sources of industrial limestone and to indicate the commercial potentialities of little-known and undeveloped deposits. These examinations were part of a long-range program of investigation of mineral resources of the Pacific Northwest. The following report on the Whitechuck travortine deposit is one of a series prepared in the course of the investigations.

Jan 1, 1949

By T. J. Ballard

"The Hog Creek mine, in lot 92 of the 17th district in Towns County, Georgia, was examined in 1890 by F. P. King, who reported the existence there of a 4-foot vein of corundum. The mine is about 2 miles west of Hiawassee, on the southern side of Ramey Mountain. Ed Burch, of Hog Creek, holds the surface rights, and the mineral rights appear to be vested in the heirs of William R. McConnell, who formerly owned and prospected the property.Examination by the Bureau of Mines showed the workings to be caved, but it was thought advisable to open the mine and uncover the reported vein. The Bureau's work consisted, of trenching and cleaning out the pits and shaft.William R. McConnell, the former owner, prospected the property in about 1890. At some tine during that operation, the prospect was visited by Francis P. Kings a geologist with the Georgia Geological Survey.3/King reported that a 4-foot vein of corundum was exposed g feet below the surface in the main cut and was opened for 20 feet along the strike. He also reported that the so-called ""Georgia rubies"" were taken from this mine.The main mine is about 2,000 feet- north of Hoc Creek on a timbered southern slope of Ramey Mountain. It lies at an altitude of about 2,100 feet, approximately 100 feet above the high-water level of the Catuga reservoir, which floods Hog Creek to a quarter of a mile above its confluence with the Hiawassee River. The nearest water is a small branch about 1,000 feet to the west.Chlorite schist is the principal host rock. It has been intruded by irregular masses of a very herd periodtite rock possibly troctolite. The schist near the surface is extremely weathered, presenting white and red laminations parallel to the schistosity. At a depth of 40 feet in the cross-cut it appears as a fine-grained green-chlorite schist. The schist strikes about N. 350 E. and dips 800 to the southeast.No corundum vein was found, and if any existed it must have been mined out after King's visit. In the pit, about 15 feet west of the shaft, approximately 150 pounds of zoisite and an occasiona1 small crystal of corundum were found imbedded in schist about 18 feet below the surface, near hard, dense troctolite."

Mar 1, 1946

By Richard L. Sayrs

"The Stiner zinc prospect near the north boundary of Union Tennessee, and the Bunch Hollow property 5 miles northeast in Claiborne County, Tennessee, were diamond-drilled by the Bureau of Mines during the period .September 1, 1944, to February 22, 1945. Seventeen holes totaling 5,687 feet were completed, 13 of which, totaling, 5.083 feet, were on the Stiner property and the remainder, totaling 604 feet, at Bunch Hollow.The Stiner prospect is about 1 mile east of the old workings known as ""New Prospect"" or ""Lead Mine Bend."" The Federal Geological Survey made a study' of the area early in 1944. The prospect was first visited in August 1944 by Bureau of' Mines engineers3/ accompanied by members of the Federal Geological Survey.4/ The locality is reached by traveling State Road 33 north-about 9 miles from Maynardsville, Tenn., thence northwest about 7 miles by an improved county road that leads to the mine (fig. 1). The tract comprises an area of about 181 acres held by G. S. Stiner of Sharps Chapel, Tenn.; it is now under option to the Universal-Exploration Co. of Jefferson City, Tenn.The Bunch Hollow property, about 5 miles northeast of the Stiller prospect, was also studied by the Federal Geological Survey previous to being;Visited by Bureau of Mines engineers in August 1944. It is reached by traveling north from Maynardsville, Tenn., on State Road 33 about 13 miles, thence northwest by county road 6 miles to the property (fig. 1). The last 3 miles of the county road are in poor repair but are passable during the entire year. The property comprises an area of approximately 300 acres and is held by the imperial Mining Co., Pressman's Home, Tenn.Few reliable data are available as to the history of the Stiner prospects themselves. However, the New Prospect mine, 1 mile west, has had a colorful past, This mine was opened in 1883 and was worked intermittently until 1918, by which time more than 65,000 tons of concentrates had been shipped. No further work was done until 1942, when the mine pillars were robbed and 1,900 tons of ore averaging 25 percent zinc was shipped to the New Jersey Zinc Co., Austinville, Va."

Apr 1, 1946

By E. D. Gardner

"The Bureau of Mines has studied blasting practices in metal mines of the Southwest. The investigation of blasting drift rounds showed among other results, that cut-holes in ground difficult to break could be chambered to advantage under some conditions.In open--cut mines, chambering nearly all holes before blasting is the common practice. Two or more free faces are generally maintained in this type of work, and the amount of explosive necessary to break any bench or bank can usually be estimated from the yardage to be moved. However, in blasting drift or tunnel rounds only one free face is available before the cut-holes are shot, and the quantity of explosive required is generally ascertained best by trial.In addition to being the most difficult to break, the cut-holes are the most important of a drift round. When the cut-holes ""break bottom"" less work is required of the other holes, and a full break of the round is generally obtained. In ground difficult to blast, extra care and expense are justified to insure that the cut-holes ""break bottom.""At many mines the work is so organized that all blasting is done at the end of the shift, and a decided advantage would have to be gained to make chambering of the cut-holes economical. Also, in many mines blasting during the shift would not be practical. One or two holes could probably be drilled during the time necessary to do the chambering. However, under certain special conditions, such as in small operations or those where ""leasers"" or contractors are working, drill holes could be chambered should there be an advantage in doing so. Moreover, in some mines it might be practical to chamber the cut-holes at the lunch hour. In ordinary rounds the cut-holes are generally drilled by noon. It would not be necessary to tear down the drill or remove tools from the face to do this work of chambering."

Feb 1, 1928

By W. S. Wright

"INTRODUCTION The Ward copper deposit was brought to the attention of the Bureau of Mines in September 1943 by John J. Knob, 217 E. Penn Street, Long Beach, N. Y. At that time all Bureau of Mines work on Seward Peninsula was being directed to the exploration of deposits of tin, a metal high on the strategic list. It was not until September 1946 that the Bureau could make a preliminary examination of the Ward prospect.ACKNOWLEDGMENTSIn its program of investigation 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 project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and performs beneficiation tests.Acknowledgment is extended to Robert S. Sanford, acting chief of the Alaska division, under whose supervision all exploratory work of the Territory is conducted."

Aug 1, 1947

By N. S. Dalal, V. Castranova, K. Van Dyke, V. Vallyathan

"IntroductionInhalation of crystalline silica is often associated with the development of pulmonary disease (Ziskind et al., 1976). Recently, it has been proposed that freshly sheared silica .may have surface properties that make it more reactive with lung tissue than aged silica, and that this unique reactivity ·of freshly crushed silica enhances its pathogenicity. A recent study in our laboratory strongly supports this theory (Vallyathan, et al., 1988a; 1988b). We found that grinding of silica cleaves bonds in a silica tetrahedral lattice generating reactive free radicals sites on the surface of the silica particles. The presence of surface radicals on freshly ground silica was monitored by electron spin resonance (ESR) spectroscopy. The ESR signal generated from fresh silica in air is characteristic of Si-0 and Si radicals. Evidence, i.e., the ESR signal after the addition of a spin trap (DMPO) and its sensitivity to ethanol, indicates that these silicon-based surface radicals can react with water to form hydroxyl radicals (OH). Results also indicate that these surface radicals make fresh silica more cytotoxic than aged silica; i.e., fresh silica causes more membrane damage as evidenced by hemolysis and lipid peroxidation. Therefore, the presence of reactive sites on the surface of freshly cleaved silica may play a significant role in its pathogenicity.If surface· free radicals are related to cytotoxicity, then screening dusts for the existence of such radicals may predict their relative pathogenicity. Since an ESR spectrometer is not available to many laboratories, the objective of this study was to develop a quick and simple technique to monitor the existence of reactive surface sites on dust. The technique chosen was the measurement of chemiluminescence using a liquid scintillation counter; i.e., an instrument which·would be accessible to most investigators."

Jan 1, 1989

By Gary P. Sames

This report discusses some practical applications of a geotechnical investigation conducted by the U.S. Bureau of Mines that can help mine operators meet revised Federal regulations in their roof control plans. The investigation, designed to characterize roof conditions near the coalbed outcrop in drift coal mines in eastern Kentucky, revealed that weathered stress-relief joints near outcrop are crucial ground control factors in the region. The joints&apos; origin and character were determined through underground mapping of many joints in coal mine roof and detailed observations and measurement of joint trends and physical characteristics in widely separated strip mine highwalls and roadcuts. This resulted in an understanding of stress-relief-joint patterns and the effect of various rock types on the intensity of weathering in the joints. That information is used in this report to show how stress-relief joints contribute to roof failure and how, through improved roof support and mine planning, safer roof support plans can be developed.

Jan 1, 1992

By G. M. Martinez

A cell concept adaptable to large-scale electrowinning of zirconium metal from zirconium tetrachloride was investigated by the Federal Bureau of Mines. Tests were made in twin cells, each 12 inches in diameter by 33 inches long. Electrowinning was performed in one chamber from which the electrolyte was transferred after electrolysis to the other chamber where it was renewed by the introduction of ZrC14 by direct sublimation. The formation of a salt plug in the connecting pipe provided a seal between the chambers. Optimum electrolyte composition, with respect to quality of the metal product (91 pct meeting ASTM standards except for the oxygen content) and current-carrying capability (about 350 amp) was determined to be 16.7 wt-pct NaF-83.3 wt-pct NaCl mixture plus ZrC14 equal to about 3 wt-pct zirconium. A twin-cell design incorporating the unit operations covered by this investigation is proposed.

Jan 1, 1976

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

Table

Jan 1, 1977

By A. D. Mah

Thermodynamic data on compounds of arsenic and sulfur were critically evaluated by the Bureau of Mines. Changes of standard enthalpy and Gibbs energy, and logarithms of the equilibrium constants were tabulated as a function of temperature for reactions involving these compounds.

Jan 1, 1982

By Roy F. Abernethy

This report describes a method developed by the Bureau of Mines for the determination of beryllium in coal ash. Samples are put into solution by standard wet chemical procedures. Interfering elements are complexed with Na2EDTA, and the beryllium is separated by extraction of its acetyl acetone complex with chloroform or carbon tetrachloride. Final determination is made with Beryllon II.

Jan 1, 1970

By George J. Conroy

Types and causes of short-circuit and open-circuit faults in mine portable trailing cables are discussed, and techniques for locating these faults are described. Time domain reflectometers (TDR) , tone generator, infrared sensing, and high voltage methods are covered. The paper summarizes Bureau of Mines research, including development of a ~DR/tone generator sender with auxiliary probe.

Jan 1, 1975

To determine the effectiveness of multiple types of fire sensors for early and reliable mine fire detection. Background The National Institute for Occupational Safety and Health (NIOSH) has evaluated the effectiveness of multiple types of fire sensors for early mine fire detection and nuisance signal discrimination. Reliable early fire detection in underground mine can be hindered by false fire alarms produced by carbon monoxide (CO) and smoke particulate emissions from diesel equipment, welding, and metal-burning activities. Another false fire alarm source is the cross-interference of hydrogen (H2) produced by battery-charging operations with a CO sensor&apos;s chemical cell. Workers can learn to ignore repetitious "false" alarms associated with these emissions. This jeopardizes their safety in the event of a mine fire.

Sep 1, 2002