High up in the Andes, there's a copper mine that's been running for over 100 years. It produces more than 400,000 tonnes of copper a year. The pit is deep, steep, and narrow — and getting more so as they go deeper.
With benches that tight, keeping control of where the ore goes after a blast is a big deal. It's common for blasted material to spill over the bench edge, which means lost ore and blocked ramps. This project was set up to deal with a few specific problems:
- Muckpile moving too far. Blasts were pushing ore down to the bottom of the pit, blocking ramps and access roads. Getting it back was expensive and slow.
- Losing ore during blasting. They needed to get more high-grade ore to the plant and less waste mixed in with it.
- Cutting drill and blast costs without dropping production — the usual balancing act.
When they looked at what was actually happening, two things stood out:
- Not enough control over where the muckpile ended up. Ore was getting shoved into spots they couldn't easily reach — like the pit floor — which hurt recovery.
- Too much stemming in the holes. The explosive charge was over-confined, so it couldn't break rock properly. That wasted energy and materials.
The takeaway was straightforward: if they could control the blast better, they'd recover more ore, reduce dilution, and bring costs down. The fix was to add air decks into the blast design. Air decks spread the explosive energy more evenly through the hole, which cuts down on heave and keeps the muckpile closer to where you want it.
