Sloughing 3 : The partial or complete collapse of the walls of a hole resulting from incompetent, unconsolidated formations, high angle of repose, and wetting along internal bedding planes. See Heaving. (Bul 10C, Bul D11)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}