Abstract
Hydraulic Preconditioning is a term given to the enhancement of underground mine natural rock mass fracture networks by inducing additional fractures into a rock mass to precondition the ground and minimize the occurrence of high magnitude seismic events during mining activity. The technology is commonly used in the application of cave mining methods to precondition strong ground and improve cavability in advance of mining. Vale has been exploring the idea of inducing fracturing into the rock mass to allow the rock to respond differently under high stress conditions.
Vale has supported the development of this technology between 2015 and 2022 through several phases (Phase 1 and 2a) of work that explored the ability to initiate and propagate fracture treatments in deep hard rock mines at Vale’s Ontario Operations. Vale has partnered with MIRARCO Mining Innovation to complete the design of a modularized underground pumping system for underground mine preconditioning treatments. Proof of concept trials were conducted with this pumping system at Copper Cliff and Creighton Mines to understand the capabilities of fracture initiation and propagation in the Sudbury rock mass environment. A future trial (Phase 2b) of a full scale hydraulic preconditioning application is currently being planned at Creighton Mine. The results of previous work and plans for the full scale trial will be presented.