With 30% fewer trucks, the fleet productivity at the Sishen iron-ore mine, in the Northern Cape, has leapt by an extraordinary 57%, Kumba Iron Ore CEO Themba Mkhwanazi said last week, when the company reported a 23% increase in production in the six months to June 30.

The contribution of contractor tonnage has been halved. The 4 100 primary shovels are moving double the tonnage per hour, compared with the same period last year.

Similarly, the large trucks are moving 64% more material, owing to increased direct operating hours, efficient use of time during the shift and an increased loading rate.

“All in all, we’ve been able to add an extra five production hours per day on the trucks,” said Mkhwanazi.

Through smart shift change and methodical use of available time, the direct operating time has improved from 12.5 hours to 17.5 hours a day.

Likewise, time lost during shift changes has reduced by 80% for the shovels and trucks.

Improvements have also been made in truck payloads and truck cycle times.

“In the past, we lost time through poor attendance, which was a reflection of team morale. I can report that we now have a highly motivated team, attendance has improved and time lost due to equipment standing idle has reduced to zero,” the head of the Anglo American iron-ore subsidiary told investors, analysts and media, which included Mining Weekly.

Not shown in the slides is the improvement made in the bench layout and design, which has enabled a shovel arrangement that supports higher productivity.

Sishen has moved on from operating with narrow opencast mine benches and waste benches are now at least 80 m wide, which permits double-sided loading.

Greater fragmentation, which directly improves shovel performance, has resulted from the decoupling of blasting practices.

Implementing the operating model at Sishen since 2015 has resulted in an 84% improvement in mine-to-plan compliance.

The model ensures stable operations that deliver predictable outcomes.

Variability is reduced and capability and efficiency are enhanced.

“A clear, stable process with minimal variations is one that is ready to progress further and so we have a structured approach for continual improvement,” Mkhwanazi said.