Buner, Khyber Pakhtunkhwa
Granite, Buner
The quarry used blasting, which fractured the blocks and cut their value. We replaced blasting with wire sawing and raised block recovery from under 20 percent to above 65 percent.
- Location
- Buner, Khyber Pakhtunkhwa
- Material
- GraniteDimension stone grade
- Scope
- Deposit assessmentQuarry planningEquipment supplyExtractionBlock export
The situation
The lease held a good blue granite deposit with export value. The site was worked by drilling and blasting. This method is fast and cheap, but it damages the stone.
Blasting fractured the blocks, so stone that could have sold as premium dimension stone was sold as aggregate at a much lower price. Saleable block was under 20 percent of the extracted volume.
What we did
Consultation
We carried out a deposit assessment with core drilling to map the joints and the areas of sound rock.
We prepared a bench plan that followed the natural joint structure. We also compared the cost of switching from blasting to wire sawing with the block price the stone could achieve in export markets.
Equipment
We supplied two quarry diamond wire saw machines, a horizontal core boring machine for wire threading, rubber moulded granite diamond wire matched to the hardness of the Buner stone, and a portable trimming wire saw for squaring blocks on site before transport.
Operations
We set up a block yard with trimming and grading so that only saleable, squared stone left the site.
The result
Saleable block recovery rose from under 20 percent to above 65 percent within the first year. With the same deposit, crew and tonnage, the site produced more than three times the value.
Trimming on site reduced freight cost per saleable cubic metre by about a quarter, because trucks no longer carried waste stone. The first export containers of granite block shipped within eight months of the first assessment visit.
Feedback
We had been working this quarry for years and taking the low price for it. Halberg told us the stone was worth four times what we were getting, then showed us on the face exactly why. They stayed until our own people could run the machine.
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