Method and apparatus for creating aggregate compacted piles using a hollow mandrel limiters upflow

A system for constructing piles aggregate, comprising: a mandrel (1) having an upper portion (9) and a rammer head (2), and a passage extending therethrough for feeding aggregate through the roller mandrel head; and said rammer head is opened to provide a passage for the aggregate to pass through the roller head off the mandrel and having a plurality of structural members (6) connected to this to allow substantially free flow of aggregate through when the mandrel is raised during operation, and to prevent the flow returns to the mandrel added during the tamping down.