The housings for the mini stacks are raised to top of bedrock, allows bonding to the bar. Because the piles had to be mounted with the existing stonework or concrete foundations, and also occasionally old hardwood stacks, with marginal disruption, unique heaps were established. These were of the bored shot grouted kind and were originally called pali radice by Fondedile due to their resemblance to the origins of trees. Today they are typically referred to as mini piles or mini heaps to separate them from those in conventional usage for structural support. The major sorts of Mini Heaps are achieved making use of boring, influence driving or screwing mini piling rigs.