Contractors working on a water seepage prevention project at the Wolf Creek Dam in Kentucky are using Wassara 150 stabilised hammers to drill vertical pilot holes ahead of the creation of a grout curtain.
Trevilicos-Bachy Soletanche joint venture is creating the curtain as part of a project to insert a cut off wall to prevent seepage. This requires very precise, safe drilling through sensitive rock strata.
The project came about after the US Army Corps of Engineers declared the dam to be at “high risk of failure” following an inspection in 2007.
The dam has had a history of problems dating back to 1968 when seepage was first detected.
Drilling the 230mm diameter, 85m deep pilot holes involves working to deviation tolerances of between 0.0015˚ and 0.0018˚.
Grout holes for the curtain walls are being drilled with Wassara W80 hammers, powered by two Cubex QX1210 rigs with on board water pumps.
The hammers are driving 95mm diameter holes 85m deep.