1 Calyx drilling

• Method of core drilling performed by the rotation of a steel cylinder and cutting with chilled shot, about 2.4 mm diameter, which cuts a formation core.

• Circulating water carries the cuttings up to a basket-like space at the top of the core barrel.

• The core is wedged into the barrel and pulled up one barrel-length at a time. Shafts up to 2 m diameter can be drilled, and holes to a depth of more than 300 m.

2 Diamond Drilling

• It is a form of core drilling which uses a rotary drill with a diamond drill bit attached in order to create precisely measured holes.

• As diamond is the hardest naturally occurring material in the world, it is ideal for creating openings in a range of materials including concrete, metal and glass.

• A diamond drill is a precision instrument, creating clean, accurate holes with diameters of between 8mm to more than 1500mm. As it is a non-percussive technique, structural integrity is maintained around when drilling.

• Every diamond drill runs water through the driving shaft to ensure that the workspace remains free of dust. They can be operated in either a vertical or horizontal direction depending on the requirements.