The first stage of the excavation phase was the dismantling of the FEBEX concrete plug :

The first stage in the operation involved dismantling of the existing concrete plug (2.7 meters long - shown below) and exposure of the bentonite blocks that lay behind.	Initially, a series of boreholes were drilled into the concrete plug:
The concrete plug prior to dismantling	Drilling boreholes into the concrete plug
The concrete plug was broken up by a hydraulic splitting techniques.	As this continued, samples were also taken of the interface between the plug and the host rock
Hydraulic splitting of the concrete	Taking samples from the rock/plug interface
	Eventually the bentonite was reached (shown left). The excavation of the bentonite is shown in the next section (FEBEX II - Excavation phase - Bentonite excavation).