The Cigar Lake Mining Test

CIM Bulletin, Vol. 85, No. 960, 1992

J.M. Marino, and Barry W. Schmitke, Cigar Lake Mining Corporation, Saskatoon, Saskatchewan

Cigar Lake Mining Corporation is presently operating an underground test mine in northern Saskatchewan, with a view to developing a high grade uranium deposit. The mining test is intended to demonstrate that the innovative mining methods designed are safe and economical. Two vertical mining methods are considered for the test:• box hole boring from the lower level; • blind boring from the upper level. In both cases, it is anticipated to freeze the ground before excavation to ensure hole stability and limit the inflow of water. Special care will be taken to minimize radiation exposure of personnel. Remote controlled equipment will be used where applicable. The access to the orebody was an important component of the test. After shaft sinking to a depth of 500 m, development work commenced at the 420 level in fractured sandstone which was grouted to restrict the inflow of formation water. The drifting continued in a section of poorly consolidated sand, clay and sandstone; this area was frozen to allow stabilization prior to excavation. At the 480 level relatively little water was encountered in the altered basement gneiss and grouting was not necessary; however, extensive ground support was required in the soft ground areas.

Keywords: Cigar Lake, Underground test mine, Vertical mining methods, Uranium mining, Mining methods, Shaft sinking, Radon emanation.