Accounting for blast movement reduces waste in the mill and maximizes ore yield—adding C$100,000 in one blast
Accurate tracking of blast movement helps improve operational efficiency at Highland Valley Copper.
An example blast demonstrates the extent of movement and recovered value. Movement occurs within all blasts, and horizontal movement variation ±50% from the mean is common.
- In this blast, measured horizontal movement ranged from 2 – 11m1 (6 – 36 ft)
- Vertical movement was up to 6.4m (21 ft)
By accurately accounting for blast movement, Highland Valley Copper:
- Avoided 35% dilution—22,7001 tonnes of very low grade waste were diverted from the mill
- Maximized ore yield—15,4001 tonnes of higher grade ore were recovered, avoiding 24% ore loss
The ore control team increased revenue by C$100,0002, which is calculated from the additional ore recovered minus the copper that would have been recovered from dilution if the ore blocks were mined in situ.
1. Numbers are generated from BMM Explorer and rounded.
2. Supplied by Highland Valley Copper and calculated at a copper price of US$5,500/t.
Image Credit: infotel.ca: contributed by Teck Highland Valley Copper
This blast map shows pre- and post-blast ore polygons, and areas of ore loss (pink) and dilution (brown). In this blast, if ore bodies had been mined in their in situ positions, 22,716 t of waste would have been sent to the mill and 15,469 t of high grade ore sent to the waste pile.
Ore loss occurs when material containing grade (ore) is incorrectly sent to a waste dump.
- When a cost is given for ore loss, it is the sale value of the metal (copper) recovered from this ore (i.e. ore tonnes x grade x recovery rate x metal price)
Dilution occurs when waste is unintentionally mined with material containing ore and sent to the mill.
- When a cost is given for dilution, it is the cost of processing the waste material through the mill