The research results of the artificial massif properties from the solid stowing the underground mining are listed. It is established that the placement unstable compounds in the goaf under gravity flow leads to their layering into several zones. It has been revealed that the activated stowing has a more uniform distribution of filler during the mixture motion in the mechanical activator at 1,0-1,5 m/sec, resulting in the increased hydration of binding materials 2-3 times and the mixture strength by 20-25%.