Drilled Mini Piles are constructed using a variety of drilling techniques to penetrate the overburden material and form rock sockets.
Concentric, eccentric or duplex systems are used to penetrate the overburden soil before down the hole hammers and rotary bits are used to penetrate the rock. This technique uses either temporary or permanent casing and the arisings can be flushed from the bore using air, water, foam, grout or polymer.
When the predetermined rock socket length has been achieved, the steel reinforcement is placed and the pile bore is filled with either concrete or grout.
This technique is particularly effective where rock penetration is required and it can overcome cobbles, boulders and mass concrete in the overburden.