Parametric study and dimensional analysis on prescribed hydraulic fractures in cave mining

摘要

Cave mining has become a popular underground mass mining method and extends its applications to more component orebodies at depths. To ensure continuous cave propagation, effective pre-conditioning of the ore body to improve its caveability and fragmentation sizes is essential. Hydraulic fracturing has been used as a preconditioning method in cave mining by creating artificial fractures in the orebody. In a previous study, the requirement for creating orientation-controllable hydraulic fractures was established and the concept of prescribed hydraulic fracturing was proposed to fill this research gap. The deep understanding of how various factors and their combinations impact prescribed hydraulic fracture propagation is important for the successful application of this newly developed pre-conditioning strategy. In this paper, the concept of dimensional analysis is employed to reduce the number of independent variables governing the approach from 19 to 10 following their identification. A procedure is also developed using the concept to project laboratory scale numerical modelling results to field scale in the absence of actual field trials.