Based on the orientation, size, and suggested competence of the rockmass, open pit and underground longitudinal blasthole stoping have been selected as the most suitable mining methods. As Brookbank is located in Northern Ontario, personnel with mining experience are assumed to be available. The mining method requires mobile equipment that is commonly used in the industry.
Open Pit Mining
Pit designs have been developed for the West Pit and the East Pit.
In the absence of a formal wall slope geotechnical evaluation, some general assumptions have been made for good quality rock. It has been assumed that 10 metre benches can be doubled up between berms and that perimeter blasting techniques, including pre-splitting, will be used to increase bench face angles.
The wall slope design parameters used for pit optimization shown that the inter-ramp wall slope could be approximately 55 degrees and the overall wall slope with one ramp crossing is approximately 46.5 degrees.
For purposes of optimization rock was assigned a slope of 50 degrees. An overburden model was not available for slope coding. Final design slopes were based upon bench face angle and berm width.
The West Pit design was generated using a 20 metre wide haulage road for two way traffic. The pit is 420 metres long in the east west direction and 85 metres wide in the north south direction and reaches a depth of 50 metres.
A smaller East Pit desig ........