Gob Seals -- An Effective Alternative to Structural Seals

Mine seals are necessary in nearly every underground coal mine to isolate mined-out areas from the ventilation network. Many seals are already in place in active mines and more need to be constructed to keep up with the development of underground coal reserves. The recent accidents involving seal failures prompted the U.S. Mine Safety and Health Administration (MSHA) to create and implement new regulations. These regulations have required the design and construction of seals that are larger and stronger than ever before. Structural seals capable of withstanding the new required design loads are very expensive. The high cost is generating a case for finding an alternative to the current practice of creating robust structural seals. An engineered solution based on proof of concept scaled experiments described in this paper yields results that show promise as an alternative to the current sealing practices. This paper defines a novel design that could be a low cost solution for the sealing of mined out areas in underground coal mines. Further research is recommended to generate and implement a rational, cost-effective engineering system. The concept of gob seals is introduced where gob material and inert mine rubble could be used to mitigate the blast effects of a methane explosion. The concept is not specifically for longwall gob isolation seals but, rather, a more broad application where seals need to meet pressure mitigation standards. The novel design solution to mitigate seal loading is verified with data from scaled tests performed in a high explosives shock tube facility located in Georgetown, KY. This data is supported by additional tests performed by other researchers at the Lake Lynn Experimental Mine.