Grant: Research Tools and Instruments - Category 1 (<$150,000)

The equipment proposed in this application will be used in support of deep mining challenges, in particular to detact and trach mining-induced straining of the rock mass. Issues such as fault slip, strain bursting and rockmass bulking during brittle failure can be better understood if the related strain field is known. Recent developments with distributed strain monitoring technology opens opportunities to fill knowledge gaps as outlined in this proposal. Having access to reliable in-situ strain measurement is critical to quantify mine system stiffness, assess energy flow during micro-seismic event propagation, fault mobilisation potential and to put in place energy release control mechanism. Access to accurate and distributed strain measurement within the rock mass will allow on one hand to increase worker safety in underground hard rock mines and on the other hand to increase our understanding of fault rupture processes. Fiber Optic Sensors (FOS) have been developed that provide high accuracy strain data and are easier to implement than mechanical based system (e.g. rod extensiometers). Also, FOS are intrinsically immune from electro-magnetic field perturbations and moisture and corrosion resistant. However, their current field of application is mostly related to structure monitoring; there is a knowledge gap concerning how to deploy this technology in underground settings, particularly within monitoring boreholes. This project aims at developing and testing installation procedures adapted to UG mines for strain measurements based on fiber optic devices. After calibration in a laboratory seting, prototype installations will be made at one or two local mines (likely Coleman (Vale) and Nickel Rim (Xtrata Nickel). Colaborations are planed with Micomo from Chile as this company has some experience in signal processing from rock mechanics applications at Coldelco mines.