Excavation of a mine shaft through deep overburden by natural freezing

CIM Bulletin, Vol. 75, No. 840, 1982

MORRIS MEDD and JOHN DE LA VERGNE, J.S. Redpath Limited, North Bay, Ontario

This paper describes the sinking of a circular concrete ventilation shaft through 110 feet of water-bearing overburden. The brine circulation freezing method was used to stabilize the walls during excavation. In order to take advantage of the cold winter weather, a custom-built heat exchanger (natural radiator) was installed in place of the standard mechanical refrigeration plant.
Keywords: Mining methods, Shaft sinking, Overburden, Freezing, Concrete shafts, Ventilation shafts, Heat exchangers, Brine, Lining.