Mining Enforcement Research Articles

Computerised slope stability analysis of refuse piles and impoundments by the simplified bishop method : Sawyer, S G; Mazzei, D S; Wu, K K US Mining Enforcement and Safety Administration informational report, N1068, 1978, 87P

Computerised slope stability analysis of refuse piles and impoundments by the simplified bishop method : Sawyer, S G; Mazzei, D S; Wu, K K US Mining Enforcement and Safety Administration informational report, N1068, 1978, 87P

Monitoring and warning instrumentation of pillar movements in salt : Ellickson, M L US Mining Enforcement and Safety Administration informational report, N1055, 1977, 11P

Monitoring and warning instrumentation of pillar movements in salt : Ellickson, M L US Mining Enforcement and Safety Administration informational report, N1055, 1977, 11P

Design and construction of a strain-gaged resin bolt for the measurement of in-situ axial loads : Sawyer, S G; Eakin, G L US Mining Enforcement and Safety Administration informational report 1039, 1976, 17P

The Roof Control Group of the Pittsburgh Technical Support Center, MESA, has designed and developed, and has employed in underground coal mines, a strain-gaged resin bolt for the in-situ measurement of axial loads. This instrumented bolt, which can be installed in cycle with regular fully, resin-grouted bolts, consists of a strain-gaged, 1-inch diameter, resin bolt that can be made in varying lengths up to 5 feet and when grouted in 1-3/8-inch holes in the mine roof, can record in-situ axial loads at any three preselected locations along the bolt's shaft. Specially designed, half Wheatstone bridges, powered by an intrisically safe strain box, give readings independent of the effects of temperature, humidity, bending, and torsion. The design and development of the strain-gaged bolt is discussed and the step-by-step procedure by which such a bolt can be constructed is given.

Investigation of the effects of thrust and hardebed washers on the installed tension of a roof bolt : Sawyer, S G; Karabin, G J; Debevec, W J US Mining Enforcement and Safety Administration informational report 1031, 1976, 18P

Investigation of the effects of thrust and hardebed washers on the installed tension of a roof bolt : Sawyer, S G; Karabin, G J; Debevec, W J US Mining Enforcement and Safety Administration informational report 1031, 1976, 18P

Criteria for slab removal at Louisiana salt mines : Lutzens, W W; Childress, L B US Mining Enforcement and Safety Administration Informational report 1047, 1976, 8P

Salt mines located in the Gulf Coast area experience the problem of potentially hazardous slabs of salt forming on pillars. A determination must be made as to the relative hazard of slabs and when they should be removed. Criteria have been developed from field observations in two Louisiana salt mines to assist mine management in determining the relative safety of a slab.

Comparative evaluation of conventional and resin bolting systems : Karabin, G J; Debevec, W J US Mining Enforcement and Safety Administration informational report 1033, 1976, 22P

Over the past few years, the use of fully grouted bolts to support the roof of underground openings has increased dramatically. While conventionally anchored bolts effectively reinforce the strata of over 80 percent of mine workings, the use of resin grouted bolts in areas of severe roof conditions has resulted in a substantial reduction in roof falls and an overall improvement in both safety and production. Specially developed strain-gaged resin bolts, compression pads and differential sag stations installed during the mining cycle have generated data reflecting the loading characteristics and resulting roof stability associated with each type of support. Additional investigations have produced optimum installation parameters of the two systems including the effectiveness of thrust/torque controls for conventional bolts and various bolt/hole diameter combinations for fully grouted rods. Theoretical analyses, coupled with the actual field and laboratory findings and numerous observations of installations, have facilitated basic comparisons of the working mechanisms and failure modes of both resin and conventional systems.

Considerations of Ground Fault Protection as Influenced by the Occupational Safety and Health Act and the Mining Enforcement and Safety Administration

The first step in recognizing the necessity of low voltage ground fault protection was taken by the 1971 National Electrical Code (NEC), Section 230-95. With the passage of the Occupational Safety and Health Act (OSHA) of 1970, more emphasis has been placed on adherence to the code. Since the establishment of OSHA, questions have been raised as to the jurisdiction between the Occupational Safety and Health Administration and the Mining Enforcement and Safety Administration (MESA). This has resulted in both agencies considering and deciding on design standards for cement plant electrical systems. Indications are that in the future, MESA standards will also recognize the necessity of adequate ground fault protection. Since the introduction of ground fault protection in the codes, there have been arguments for and against the methods of applying ground fault protection. It is for this reason that the present code requirements are minimal. In order to provide the electrical service reliability required by modern cement plants, more extensive protection is required. The intent of this paper is to evaluate the new requirements of ground fault protection. It also examines how we, as engineers concerned with electrical power systems in cement plants, approach the problems of providing safe reliable electrical systems which meet applicable code requirements and which also function satisfactorily in relation to plant operation.

On-filter analysis of quartz in respirable coal dust by infrared absorption and X-ray diffraction.

An infrared spectrometric and an independent X-ray diffraction method were developed for the analysis of α-quartz in airborne respirable coal dust. Sensitivity is such that the procedures can be used for analysis of the material from a single membrane filter such as is used for personal samplers by the Mining Enforcement and Safety Administration (MESA) in its enforcement program. Sensitivity down to less than 10 µg of quartz is obtainable. The methods are reasonably precise with good agreement between them. Their accuracy is limited by the unavailability of a true quartz standard. In both procedures dust is transferred ultarsonically from the collection filter to a small area of a second filter which is relatively infrared-transparent and has a weak X-ray background. This technique provides a substantial increase in area concentration and attendant sensitivity. Both methods, in principle, are capable of use with a wide variety of solid materials.