Ore mining entails blending of ore into the mining unit plant to provide a stable grade input.
This allows for optimum outcomes in terms of recovery, without having to change plant settings frequently or on the run. Elimination of unplanned feed material type variation, which in turn allows for optimised recovery plant set points, is the main objective of blending.
For each mining block there are typically 3 main blends – low grade at the start of the block, a medium blend for the majority of mining and high grade at the end. At Jacinth-Ambrosia two dozers work in tandem, with each assigned to a specific set of “slices” to ensure blend is realised.
- Geologists prepare the blend twice a day, one for day shift and one for night shift. Development of the blend is done by interrogating the reserve model data and applying dozer production rates to specific material types and slices. Colour and relative level define each slice.
The blend plan is delivered to the mining contractor for that shift. Feed grade is monitored by the control room operator who liaises with the dozer operators to manage any significant variance.
Ore blending process
Ore blocks – Jacinth deposit, Eucla Basin, South Australia.
Ore blocks – Woornack and Pirro deposits, Murray Basin, Victoria.
Dozer push mining method.