Porathur, John Loui Roy, Pijush Pal Shen, Baotang Karekal, Shivakumar Highwall Mining: Applicability, Design & Safety - Boca Raton CRC Press 2017 - p.323 Subjects--Topical Terms: Hydro-geologyWeb PillarEntry SpanSeam-Scale Geology Dewey Class. No.: 622 P69H