In 2010 DDH 397 and DDH 400 were both lost when the drill rigs failed.

Experience at Schaft Creek has shown that difficulties encountered at shallow

depths of the drill hole can and most often do lead to more significant drilling

issues at greater depths. Deflection of the drill stem in shallow, very coarse

overburden or poorly consolidated bedrock increases down-hole torque, leading to

excessive abrasion and wear on drill rods. Continued wear on the rods

compromises their strength and integrity, thus increasing the potential for breaks

in the drill string and potential loss of equipment.