Deming said there is joy in work, and I certainly found mine at a gold operation. I’d helped design a Change Leader Program built around Lean, Six Sigma, and the personal skills needed to make improvement stick. The format was familiar: learn the tools, run a project, demonstrate measurable benefit, then collect a certificate and a photo with an executive. My joy came from coaching two dozen of these legends — sharp people, curious minds, and a few who could see the operation in ways others didn’t.
We were mine‑constrained, with a mill that didn’t need to run flat‑out to meet production targets. The processing crews were highly skilled and deeply professional, with a handful of Change Leaders among them. Upstream mining projects delivered instant value; downstream plant projects were about respecting the ore and the circuit — squeezing out recovery, reducing cost, and improving reliability. Best of both worlds and simply Heaven for a BI guy.
One day, my Metallurgist Change Leader came to me with a half‑question, half‑statement: “We strip carbon on a fixed schedule… but I don’t think it’s fully loaded when we do. And every strip costs LPG, caustic, cyanide, labour, and carbon life. What if we don’t actually need to strip as often?”
I laughed. “I don’t know, mate — but plenty of routines exist because they’re either convenient or consistent, not because they’re optimal. Tell me what you’re thinking.”
He explained his theory, and we planned. First rule: do nothing yet. We needed baseline data. He pulled historical carbon loading data, solution gold concentrations, carbon activity trends, and adsorption performance across the circuit. He analysed the distribution, the variance, and the downstream metallurgical indicators.
The result was clear: Carbon was being stripped at around 2,800 g Au/kg, but the circuit could comfortably support 4,200 g Au/kg without breakthrough, without rising solution gold, and without any impact on Recovery — the real financial driver.
Gold adsorption onto activated carbon follows non‑linear Langmuir kinetics. Adsorption is fast at low loadings and slows as carbon approaches equilibrium, but it does not suddenly collapse. As long as carbon activity, residence time, and carbon concentration are maintained, the carbon continues to polish the circuit effectively. His analysis showed exactly that: Recovery remained stable, and solution gold stayed low.
With confidence in the data, he presented a plan to decision‑makers: Incrementally extend strip intervals, allowing carbon to reach higher loadings, while monitoring solution gold, carbon activity, GIC, and tails grade. Move from daily stripping to every 3–4 days, and quantify the financial benefit.
The results were outstanding.
- LPG consumption dropped significantly, a minor piece of the energy puzzle but still a cost.
- Regeneration frequency fell, reducing carbon attrition, extending carbon life and saving the production team time and effort.
- Carbon replacement cost decreased, because less thermal damage meant less breakdown.
- Power and reagent use declined, simply because the strip circuit ran less often.
We called the upper limit at 4,200 g Au/kg, and often the strip was done with three days of grace. The plant ran smoothly, adsorption remained stable, and Recovery didn’t budge. For all of that, we retained the right to strip the carbon in alignment to shipping timings and business needs.
We tracked the improvement for a year. The savings covered his salary — and anyone who knows Plant Mets knows that’s no small achievement. Importantly, we did the job efficiently, with less resources – something I was happy to highlight in the next ISO14001 audit for ‘extra credit’.
Ultimately, he presented to the site Leadership Team, the Corporate Exec team, earned his certificate, his polo shirt, and a graduation photo. More importantly, he walked away with a passion for challenging the status quo. And that, ladies and germs, is why I love my job.