She drew a Shewhart control chart on a whiteboard in the control room. Upper control limit. Lower control limit. And in the center, the target P80 of 150 microns.
The average was just a ghost. The plant was either choking or starving, never steady. Statistical Methods For Mineral Engineers
Elara was the site’s mineral processing engineer, but her secret weapon wasn't a froth flotation cell or a high-pressure grinding roll. It was a battered copy of Montgomery’s Introduction to Statistical Quality Control and a stubborn refusal to trust averages. She drew a Shewhart control chart on a
The control room fell silent. A junior metallurgist raised a hand like a schoolboy. “So... we should intentionally lower throughput?” And in the center, the target P80 of 150 microns
Gus blinked. “Speak English.”
“You’re chasing your tail,” she said. “The crusher power draw spikes, you back off. It drops, you tighten. But the lag in your feedback means you’re always reacting to what happened five minutes ago. By the time you fix it, the feed has already changed. You’re creating the instability you’re trying to solve.”