Case Study:
Mill throughput improved by 46 % with reduction of critical size particles by 11 %
Location: Phu Kham Mine, Laos, Southeast Asia
Project Type: Copper, Gold, Silver Open pit mine
Products Used: E*STAR
1. To increase the mill throughput by keeping the actual powder factor
2. To reduce critical size particles
3. Increase production of copper, gold and silver concentrate
The History
Phu Kham Mine is copper-gold-silver operation located in Laos, Southeast Asia. Annual digging rate in 2017 was cca 60M tons. Annual production in 2017 was 100 000 tons of copper, 40 000 oz of gold and 640 000 oz of silver.
Typical hard ore blast used following parameters: PF 1,6 kg/m3, hole diameter 200 mm, hole depth approx.. 11 m, burden 3,5 m, spacing 4,5 m, stemming 4 m, subdrill 1 m, explosive 70/30 bulk emulsion. There were no restrictions on PPV or AIR O/P. Non-electric detonators and typical timing was used.
The Test Blasts
First set of trials were done with same non-electric detonators / timing and increased powder factor. Standard powder factor was increased by 50 % to 2,4 kg/m3. Mill throughput was increased by 9 %, critical size amount was reduced by 8 % and fines amount was increased by 5%.
Second set of trials were done with the same powder factor and with E*STAR electronic detonators and with new timing inter-hole and inter-row delays. This set of trials was focused on calculation delay based on blast geometry, rock properties, explosive properties etc.
The Austin Solution
Typical hard ore blast, test blasts with increased PF and electronic tests blast were put in blast design modelling software called Paradigm. Based on inputs and software papers database, best timing (inter-hole and inter-row delay) was calculated and recommended.
The Outcome
- Improved blast fragmentation
- 46 % increment of mill throughput production
- 11 % reduction of critical size amount (25 – 75 mm)
- 14 % increment of fines (under 10 mm)
- Heave / muckpile height reduction
- Muckpile movement control
- Increased safety and blasting control
- Improved timing has bigger effect than increased powder factor
Major improvement, mill throughput increment, is shown in graph below. Black line is representing typical hard ore blast with PF 1,6 kg/m3, grey and yellow line is representing test blasts with PF 2,4 kg/m3 with the same non-electric timing and blue line is representing test blast with improved electronic timing and normal PF 1,6 kg/m3.
After finishing all tests, blasting operation has been switched to E*STAR electronic detonators in hard ore blasting.