The mining method used by the Ambatovy Joint Venture is open pit mining using an excavator/truck operation. Bench mining is executed in opened deposits using hydraulic backhoe excavators equipped with 5.4 m3 buckets and a combination of rigid and articulated haulage trucks. The mine operates 365 days per year. Ore is either directly fed to the OPP or stockpiled for future processing.
Pit Limits.
The pit limits are well defined; generally, the base of the pits is the floor of the saprolite (the exception being if the slope is greater than 27° when the bedrock may form the pit floor), whilst the lateral extents are constrained either by lease/environmental boundaries or economic limits.
Pit design parameters:
- Ramp width (single/double) - 30 m
- Ramp gradient - 8 %
- Bench height - 4 m
- Bottom pushback minimum size - 0 m
- Standoff from haulroad - 10 m
- Standoff from boundary - 30 m
- Haulroad gradient - 8 %
- Haulroad section - 300 m
- Pushback minimum width - 30 m
- Minimum switchback width - 60 m
- Bench face angle (batter angle) - 45 m
- Berm width – 8 m.
A mixed fleet is used at Ambatovy, large Cat 6030 and 6020 excavators and Cat 777 haul trucks (90-t payload) move the bulk of ore and waste material. A smaller fleet of Cat 385 excavators (90-t, 5.4 m3 bucket) and Cat 745 (41-t payload) articulated dump trucks are used for residual ore mining, stockpiling reclamation, q ........
