Mineração Aurizona — AI Autopilot on the Gold Grinding Circuit
The company
Mineração Aurizona (MASA) runs a gold mine and processing plant in Maranhão, Brazil. Since January 2026 it belongs to CMOC Group — the world’s largest cobalt producer and one of the top eight copper producers, listed in Hong Kong and Shanghai — as part of a US$1.015 billion acquisition.
The test described here ran from January 10 to February 5, 2024.
Challenge
The grinding circuit set the pace of the whole plant — and manual control was limiting its throughput and consistency. Operators could not hold optimal setpoints 24/7 as rock type, feed blend and percent solids shifted underneath them.
Method
25-day controlled test (January 10 – February 5, 2024) on the same grinding circuit, alternating AI-guided and manual operation in 48-hour cycles to control for rock type, feed blend, percent solids and operating rates.
Only periods with ≥85% active operational hours entered the analysis — 265 operational hours per mode — ensuring a like-for-like comparison. The test followed a two-year collaboration between Brainiall and the producer, and was delivered in partnership with SoftwareOne on AWS cloud infrastructure.
Inside the circuit
A predictive model of the grinding circuit, built over two years with the plant’s process engineers, ran the AI Autopilot. It read the circuit’s live process data and sent setpoints straight to the plant’s automation system in real time, inside safe operating ranges, 24/7.
One click returned control to the operator, and the safety systems were untouched throughout the test.
Results
- 435 t/h (AI) vs 412 t/h (manual) — +6% throughput
- 115,347 tons processed under AI vs 109,079 tons under manual, over matched 265-hour windows
- +3% on hard ore (Wi ≥ 14 kWh/t), above plant design rates
- Particle size (p80) practically the same — less equipment stress and more predictable downstream flotation recovery
- Specific energy fell ~2% per ton: 20.7 vs 21.1 kWh/t (test report)
- ≈2,694 additional ounces/year — ≈$781K incremental annual profit (net of AISC)
Results may vary with ore grade and operating conditions.
Client confirmation
In September 2026, Mineração Aurizona confirmed in writing that the solution was implemented and evaluated under real operating conditions, delivered consistent results and met the criteria defined for the test.