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By George J. Carter, George H. Todd, Hal J. Kelly

In July 1956, the Bureau of Mines and the J. R. Simplot Co. participated in evaluating and beneficiating drill-hole samples from the Bovill, Idaho, clay-silica deposit and in tests of the beneficiated products. The geology, mineralogy, beneficiation, and potential uses of the clay and quartz fractions of the Bovill deposit are described. Test work showed that a filler-grade clay having an apparent spectral reflectance of 78 percent can be made by bleaching, and by removing some of the submicron-size particles. A quartz product suitable for the manufacture of glass containers can also be made.

Dec 1, 1963

Objective: To identify and evaluate a durable, flexible, and practical stopping to direct ventilation airflows in large-opening metal/nonmetal mines.

May 1, 2006

By Rimas Pakalnis, Catherine A. Dreesbach, Lewis A. Martin

Instrumented cable bolts developed at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health were used in conjunction with existing ground control systems to monitor rock mass loads at Tg Soda Ash's trona mine, Granger, WY. Axial and shear loads were determined to levels of strain gauge accuracy of ±5 N or ±5 micro strain. These gauges were embedded in a remanufactured king wire that replaced the conventional king wire. Cable bolt performance, quality of grout, and installation techniques were also assessed. By using instrumented cables, a mine operator can determine axial load along the cable at predefined gauge locations. These data provide necessary input for an operator to design a safer working environment for miners.

Jan 10, 2000

By T. J. Lutz, G. T. Homce

A standard Ford1 4600 agricultural tractor was converted to remote control to perform ASAE/SAE field upset tests (rear rollover and side rollover). This paper discusses the engineering process to develop a remote-controlled tractor in determining the critical parameters of operation, to choosing appropriate actuators, designing the circuitry to control them, installing the actuators on the tractor, testing the system for functionality and then conducting numerous overturn tests. The system uses off-the-shelf components for simplicity, replaceability, and economic concerns. The remote control system has withstood 21 tests to date with no failures and will continue to be used for at least three more years of testing.

By Thomas H. Dubaniewicz, Gerald R. Cucci, Gregory M. Green, Kenneth L. Cashdollar

New types of industrial instruments use fiber-coupled law energy to power remote serum. Fiber-optic based instruments are useful in classified (hazardous) locations found in many industrial plants because the fiber provides a natural barrier against accidental electrical discharge into potentially explosive atmospheres. However, current safety standards do not cover the use of laser-powered fiber-optic instruments in potentially explosive environments such as found in coal mines. The U. S. Bureau of Mines began an investigation of laser-powered fiber-optic instruments in explosive atmospheres in support of the standards-making process. A commercial fiber-optic interface system, modified to sin relate several worst-case operating conditions, ignited explosive hydrogen-air mixtures. Worst-am simulations consisted of disabling a safety shutoff feature, operating the laser at significantly higher powers than intended for normal operations, and cleaving fiber-optic connections to direct laser energy onto selected absorptive materials. At the highest power level available, the fiber-optic interface system did not ignite selected methane-air mixtures. The obtained data should prove useful in establishing appropriate safety standards.

By Eric Zahl, John Dunford, Hamid Maleki

Coal bumps are defined as sudden failures of rock and coal near entries that are of such a magnitude that they expel large amounts of material into a mine opening. Coal bumps are influenced by geologic conditions, the geometric design of coal mine excavations, and the sequence and rate of extraction. Researchers from private industry and the National Institute for Occupational Safety and Health have studied mechanisms of violent failure and have identified individual factors that contribute to coal bumps. In an attempt to develop tools for assessing coal bump potential, the authors initiated a comprehensive study using information from 25 case studies undertaken in U.S. mines. Multiple linear regression and numerical modeling analyses were used to identify the most significant variables contributing to coal bumps (excluding bumps related to fault-slip). Twenty-five geological, geometrical, and geomechanical variables were considered initially. The most important of these variables were then identified as (1) energy as calculated using the mechanical properties of the strata, depth of overburden, and joint density, (2) mining method, (3) pillar factor of safety, and (4) stress gradient and yield characteristics.

By W. C. Smith

The U.S. Bureau of Mines examined previous research on rib stability in an effort to develop a practical approach to understanding, characterizing, and controlling weak rib conditions in underground coal mines. Because success in stabilizing ribs depends on a basic knowledge of how weak ribs behave, the report reviews the mechanics of rib failure and the relationship of coal mine geology and pillar constraint to rib instability. Strategies for choosing an effective method of rib support are considered, and various rib support methods are discussed. Finally, the report documents techniques for monitoring ribs and use of models to assess rib stability; such monitoring and modeling can also help determine the most effective method for roof support.

Jan 1, 1992

By O. C. Ralston, L. H. Duschak, R. D. Pike

Much detailed information on the production of plastic magnesia from magnesite mined near Chewelah, Wash., was accumulated during a cooperative investigation conducted by the Bureau of Mines and the Northwest Magnesite Co. at the laboratories of the University of California in 1919-1921. This bulletin gives mainly the results of the work done with Chewelah magnesite, supplemented by data on similar work with other magnesites, particularly those of California, in the endeavor to produce a plastic magnesia that would be satisfactory for making the so-called " Sorel" cement composition flooring, stucco, and plasters. As standardized methods £or testing such compositions did not exist, it was necessary to examine carefully the various methods in use and choose those that seemed appropriate. In consequence, this report contains many tests made by the methods selected and can be used £or reference by those who wish to adopt standard methods of testing.

Jan 1, 1925

During 1999, there were six fatalities in surface mines involving haulage equipment colliding with a smaller vehicle or person, or backing over the edge of a dump point. All of these fatalities can be attributed to the extensive blind areas around large haulage equipment. Researchers at NIOSH are investigating various technologies that can be used to monitor these blind areas and provide information on nearby obstacles to an operator. So far, the technologies listed below have been tested on dump trucks used in surface mining. The selection of these systems was based on their ability to handle the tough environmental conditions found in mining operations and how well they detected obstacles out to 40 or 50 feet beyond the rear of large dump trucks. Some of the manufacturers of available collision warning and camera systems are also listed.

Jan 1, 2001

By S. J. Page, J. A. Organiscak

Airborne respirable dust surveys were conducted at six surface coal mines to investigate the effectiveness of dust control methods used on rotary rock drills and bulldozers. Dust controls commonly used on drills include a dry dust collection system, exhausting from a shrouded area around the collared hole, and an enclosed drill operator cab, filtering airborne dust from the cab. Bulldozers are also typically equipped with an enclosed operator cab as a dust control measure. Airborne respirable dust sampling was conducted near each equipment's source of generation and inside its enclosed cab. Silica analysis was performed on the dust samples to determine the percent silica content in the dust generated at the six mining operations. An additional eight- month follow-up of dust sampling was also conducted in the enclosed operator cabs of several rock drills and bulldozers. Data were analyzed for long-term variability of accepted control methods to abate dust and silica levels. The highwall rock drill was the major and most variable dust source as compared to the bulldozer, generating dust levels, on average, one order of magnitude higher than dust levels of the bulldozer. Four of the six drills surveyed had dust containment and capture problems at the shrouded drill table above the lple. Repairs or modifications to three of the drill dust collection systems were shown to reduce dust levels by more that 50% next to the shrouded drill table. The enclosed operator cabs provided more than 90% and more than 40% lower dust levels than at the dust source for the drill and bulldozer, respectively. Long-term sampling of several of these highwall drills and bulldozers showed that the dust levels in the drill cabs were frequently higher than 0.2 mg/m3 and more variable than in the bulldozers. The bulldozer dust levels were frequently below 0.2 mg/m). Future research should focus on improving some of the deficiencies present in the drill's primary dust collection system, and developing quality control methods to ensure the integrity of enclosed cab protection for equipment operators.

By Thomas E. Marshall, Anthony T. Iannachione, Leonard J. Prosser

The location and time of 2,007 microseismic emissions from a limestone mine in southwestern Pennsylvania were compared with the development of mine faces and the characteristics of the mine layout. Based on analyses of these results, the occurrence of roof failure zones appears to be associated with certain characteristics of the mine plan. It was determined that significant relationships exist between the intensity of the microseismic activity and the scale of the roof failures Microseismic activity associated with these roof falls occurs In distinct episodes, with the final failure event occurring during approximately a 12-hour period. Each roof fall episode appears to be composed of dozens of distinct roof beam failures. As each beam fails in shear and tension, tens to hundreds of audible noises representing rock fracturing or bedding plane separation can occur. While every roof fell can be viewed as unique, certain mechanistic similarities can be realized through careful observation and monitoring of these complex systems. Understanding these similarities in characteristics allows mine personnel to design the most effective and efficient control technique.

By L. J. Prosser, A. T. Iannacchione

From 1991 through 1995, 44 miners out of a total workforce of less than 2,000 were fatally injured in the stone industry. Of these, 12 occurred at underground mining operations with nine deaths resulting from roof or rib falls. A safer environment can be achieved by evaluating the nature of the hazardous ground and by developing more efficient and effective ground-control strategies Roof and rib conditions were observed and assessed in 33 underground stone mines in Illinois, Indiana, Kentucky, Maryland, Missouri, Pennsylvania and West Virginia (Fig. 1). Hazard assessment indicated that the ground failures that occurred under moderate to substantial overburden. i.e., >30 at (100 ft), were caused by stress concentrations and geologic strictures. Ground failures near the surface are caused by solution (water) processes. Selection of the mining horizon and mine-layout decisions tremendously influence ground stability.

RI 9527. Effective Hazard Recognition Training Using a Latent-Image, Three-Dimensional Slide Simulation Exercise, by E.A. Barrett and K.M. Kowalski. Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, 1995. NTIS stock number: PB95-170379. Rl 9531). Computer Modeling and Analysis of The Greens Creek Mine, Admiralty Island, AK, by MJ. Beus and T.J. Orr. Spokane. WA. -U.S. Department of the Interior, Bureau of Mines. 1995. NTIS stock number: PB95-176418. RI 9600. Application of Field Measurements and Computer Modeling to Evaluate Deep Mine Shaft Stability in Northern Idaho, by M, J. Beus, T. J. Orr and J. K Whyatt. Spokane, WA: U.S. Department of the Inferior. Bureau of Minus. 1996. NTIS stock number: PB96-140181. [ ]

Jan 1, 1995

By Karl L. Kithil, Richard B. Moore

This bulletin presents a summary of available information regarding the sources of uranium, radium, and vanadium, the methods used in treating the ores, and the uses of the finished products. In particu- lar the paper describes the ores found in the United States, giving especial attention to those characteristics of the ores and the conditions of their occurrence that affect mining and treatment.

Jan 1, 1916

By Wilbur I. Duvall, Thomas C. Atchison, David E. Fogelson

The breakage of rock by explosives depends largely on the ability of an explosive to transfer its stored potential energy to the rock as strain en- ergy. Therefore, the relative rock-breaking abilities of explosives can be determined indirectly by determining the relative amounts of strain energy transferred to the rock at the time of detonation. This report presents experimental data on the strain energy contained in explosion-generated strain pulses in a granite gneiss. Six explosives were tested. The scaled total radial strain energy E/W flowing outward through a spherical shell of scaled radius R/W1/3 surrounding the point of detonation was found to follow an exponential decay propagation law of the form Analysis of the data showed that the intercept parameter H depended upon the type of explosive used but that the absorption coefficient B was practi- cally independent of the type of explosive. Comparison of the intercept pa- rameter H and the calculated energy of the explosive showed that the percent- age of explosive energy transferred to the rock increased linearly as the ratio of the characteristic impedance (product of density and propagation velocity) of the explosive to that of the rock increased toward unity. From 5 to 9 percent of the calculated total energy released by the explosive was transferred to the rock as radial strain energy.

Dec 1, 1959

By Van H. Manning

PETROLEUM INVESTIGATIONS. The work of the petroleum division of the Bureau of Mines during the period of the war was under the supervision of Chester Naramore, chief petroleum technologist. In its petroleum investigations the bureau cooperated freely with other Government bureaus and acted as a source of information on petroleum matters. COOPERATIVE WORK ON INTERALLIED PETROLEUM COMMISSION. On July 15, 1918, Mr. Naramore and W. E. Perdew, chemical en- gineer of the bureau, left for London to act as representatives of the United States Fuel Administration and the United States Shipping Board on the Inter-allied Petroleum Commission. Numerous con- ferences were held with representatives from France, England, and Italy on specifications and requirements of the various allied Govern- ments for petroleum products, and for this purpose meetings were held in London, Paris, and Rome. EXAMINATION OF PETROLEUM FACILITIES IN FRANCE. The storage facilities and the transportation system in France were studied, and recommendations based on the information gained were made to the director of the oil division of the Fuel Administra- tion and to the chairman of the Shipping Board. Refinery plants in France were inspected, as well as filling stations and shipping facilities from ports in France and Italy to the various fronts and the petroleum base of the American Expeditionary Force at Romorantin. France. At the request of Ambassador Sharp, a re- port was prepared on the advisability of developing the petroleum resources in France.

Jun 1, 1919

By A. B. Hooker, L. C. IlsLey

 Previous publications relating to permissible methane detectors covered investigations of the detectors from January 1922 to January 1,1937. All of these detectors are obsolete, or the designs have been modified under extensions of the original approvals. This report covers the investigations of detectors since January 1, 1937, including the present permissibility requirements as to design and performance and a brief description of each detector.

Apr 1, 1942

Jul 1, 2003

Dec 1, 2007

By Eric G. Zahl, John P. Dunford, Hamid Maleki

Coal bumps are influenced by geologic conditions, the geometric design of coal mine excavations, and the sequence and rate of extraction. Researchers from private industry and government agencies around the world have studied mechanisms of violent failure and have identified individual factors that contribute to coal bumps. To develop predictive tools for assessing coal bump potential, the authors initiated a comprehensive study using information from 25 case studies undertaken in U.S. mines. Multiple linear regression and numerical modeling analyses of geological and mining conditions were used to identify the most significant factors contributing to stress bumps in coal mines. Twenty-five factors were considered initially, including mechanical properties of strata, stress fields, face and pillar factors of safety, joint spacings, mining methods, and stress gradients. In situ strength was estimated in 12 coal seams where uniaxial compressive strength exceeded 2,000 psi. Allowances were made for favorable local yielding characteristics of mine roof and floor in reducing damage severity. Pillar and face factors of safety were calculated using displacement-discontinuity methods for specific geometries. This work identified the most important variables contributing to coal bumps. These are (1) mechanical properties of strata, including local yield characteristics of a mine roof and floor, (2) gate pillar factors of safety, (3) roof beam thickness, joint spacing, and stiffness characteristics, which influence released energy,(4) stress gradients associated with the approach of mining to areas of higher stress concentrations, and (5) the mining method. By combining the strength of both analytical and statistical methods, new capabilities were developed for predicting coal bump potential and for building confidence intervals on expected damage.

Jan 5, 1999