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Reducing Respirable Dust Levels During Bag Conveying and Stacking Using Bag and Belt Cleaner Device

Description: Abstract: The U.S. Bureau of Mines has designed and tested a system called the Bag and Belt (leaner Device (B&BCD) to reduce dust levels in and around the bag conveying and stacking process. The device physically cleans either 22.7 kg (50 lb) or 45.4 kg (100 lb) paper bags by using a combination of brushes and air jets. It is completely self-contained and is kept under negative pressure by a baghouse to ensure that dust and product removed from the bags during cleaning does not flow into the work environment and contaminate workers. The bags travel through the device on a chain conveyor, which permits any product or dust cleaned from the bags to fall into a hopper at the bottom of the device and be recycled back into the process via a screw conveyor. Once exiting the B&BCD, the outside of the bags and the conveyor are essentially product and dust free. The B&BCD was evaluated at two mineral processing plants to determine reductions with the device in use. The results of both field evaluations showed that the amount of product removed from the outside of the bags varied from 77 to 93 pct.
Date: 1995
Creator: Cecala, Andrew B.; Timko, Robert J. & Prokop, Alexander D.

The Reduction of Airborne Dust Generated by Roof Bolt Drill Bits Through the Use of Water

Description: Abstract: In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.
Date: 1995
Creator: Sundae, Laxman S.; Summers, David A.; Wright, Douglas & Cantrell, Bruce K.

Report on the Investigation of the Fire at the Liquefaction, Storage, and Regasification Plant of the East Ohio Gas Co., Cleveland Ohio, October 20, 1944

Description: Report issued by the Bureau of Mines over investigations conducted on the 1944 fire at the East Ohio Gas Company. Descriptions of the plant, and construction of the gas tanks are listed. A detailed description of the disaster, and its aftermath are also presented. This report includes tables, maps, illustrations, and photographs.
Date: February 1946
Creator: Elliott, M. A.; Seibel, C. W.; Brown, F. W.; Artz, R. T. & Berger, L. B.

Stemming in Metal Mines. Progress Report 2

Description: Report issued by the U.S. Bureau of Mines on the progress made in metal-mine stemming. Different types of stemming methods and testing procedures are presented. This report includes tables, illustrations, and photographs.
Date: August 1940
Creator: Johnson, John A.; Agnew, Wing G. & Mosier, McHenry

Stemming in Metal Mines. Progress Report 3: Relative Advantages and Disadvantages of Different Types of Stemming and No Stemming When Used with 60 Percent Ammonia Gelatin Dynamite at the Mount Weather Testing Adit

Description: Report issued by the U.S. Bureau of Mines on the progress made in metal-mine stemming. Previous reports have been presented impartially, or under different procedures. This report contains updated progress results from current procedures and mine conditions. The report includes tables, and illustrations.
Date: February 1942
Creator: Johnson, John A.; Agnew, Wing G. & Mosier, McHenry

Stemming in Metal Mines. Progress Report 5: Comparison of Dust and Gases Produced from Blasting Charges of Dynamite in Drill Holes, in Bombs, and in Mud-Cap Shots

Description: Report issued by the U.S. Bureau of Mines on the experiments conducted on stemming in metal-mines. As stated in the introduction, "its purpose is to compare the amount of dust and gases produced as a result of blasting charges of dynamite (1) in drill holes, (2) in bombs, and (3) in mud-cap or adobe shots" (p. 1). Dust and gas concentrations gathered from the experiments are listed. This report includes tables.
Date: December 1942
Creator: Johnson, John A. & Agnew, Wing G.

Stress Ellipsoid Determination in a Rock-Burst-Prone Area at a 4,000-Foot Depth, Galena Mine, Wallace, Idaho

Description: Report issued by the Bureau of Mines over a study on "stress determinations in an area known to be under high stress concentration induced by prior mining operations" (p. 2). The geology, procedures, and instrumentation are discussed. This report includes tables, illustrations, and photographs.
Date: August 1967
Creator: Ageton, Robert W.

Structural Analysis of a Mechanized LHD Trench Undercut Caving System

Description: Abstract: This U. S. Bureau of Mines (USBM) report presents results of stress analyses and field observations to investigate the effects of elevated trench drifts on the structural stability of rock mass zones surrounding a production draw drift in a mine utilizing a mechanized load-haul-dump (LHD) trench undercut panel caving system. A two-dimensional boundary-element mine stress model was developed to predict the locations and extent of damaged rock mass zones surrounding draw drifts where adjacent, parallel trench drifts are either elevated or not elevated above the LHD production draw drift level. A Mohr-Coulomb shear-failure criterion was obtained directly from in situ borehole shear test data. Hoek-Brown shear-failure parameter values were computed from borehole-shear and triaxial test data. A procedure is described to estimate these parameters when a rock mass rating (RMR) value and triaxial data on intact samples exist, and no borehole shear test data exist. Results indicate that trench drifts, elevated to the level equal to the height of the LHD production draw drift, would not minimize material damage nor significantly enhance the stability of rib and crown pillar zones surrounding production draw drifts in the mechanized LHD trench undercut caving panel investigated at this mine.
Date: 1995
Creator: Jude, Charles V.