BOREHOLE B-17 Cave, Kopili - Umrong

Herbert Daniel Gebauer - 24/03/2016

No penetrable cave entrance is known to give access to an active stream cave passage which was accidentally intersected »in one drill hole no. B-17 … which encountered limestone under 86 m of shale, sound of running water was heard implying movement of water with considerable velocity. Subsequent investigation by test grouting indicates that the movement of water has been controlled by grouting, as revealed by post grout water loss tests« (DUTTA & THOMAS 1970: 1034 fig. 4A, 1035, 1036 fig 6). SITUATION: Bore hole B-17 is said to be »located on Kopili - Umrong divide« (DUTTA & THOMAS 1970: 1035) or on the interfluve between these two rivers (confluence N25°36': E92°44') and apparently near (unspecified map datum probably Everest 1830) N25°28'20”: E92°39'45” (DUTTA & THOMAS 1970 fig. 2 geological plan).