Weir ENDURON Optimil vertical stirred mill: circuit design and energy notes for engineers
Reviewed by Tom Sullivan

First reported on Australian Mining
30 Second Briefing
Weir has launched the ENDURON Optimil vertical stirred mill to cut grinding energy use and operating costs in fine and ultrafine circuits as ore grades decline and power prices rise. The mill targets regrind and tertiary duties, using a vertical, high-intensity stirred design to increase power density and improve media utilisation compared with conventional ball and tower mills. For process engineers, the key implications are potential circuit downsizing, lower specific energy (kWh/t) and reduced water and media consumption in modern concentrators.
Technical Brief
- ENDURON Optimil uses a vertical, high-intensity stirred mechanism to maximise power input per unit volume.
- Mill design targets fine and ultrafine grinding in regrind and tertiary circuits handling complex ores.
- Vertical configuration improves grinding media residence control compared with conventional horizontal ball mills.
- Stirred mechanism promotes more uniform stress distribution on particles, improving breakage efficiency at small sizes.
- Weir positions the mill for operations constrained by energy tariffs and water-use regulations in modern concentrators.
- Product is aimed at brownfield circuit retrofits where footprint and structural load capacity are limited.
- Integration is intended with existing Weir process equipment portfolios, simplifying OEM interface and service strategies.
- Launch responds to operators seeking circuit designs resilient to declining head grades over remaining mine life.
Our Take
Across recent Mining coverage, Weir appears repeatedly in product and optimisation pieces, and the new ENDURON Optimil mill sits alongside its ESCO® liner and ENDURON® screen panel push into African comminution circuits as part of a broader ‘throughput plus energy’ value proposition rather than stand-alone equipment sales.
The launch of Optimil in Australia comes just as Micromine, now part of Weir, rolls out its Momentum 2027 planning and scheduling tools, suggesting Weir is positioning to link mine planning data with downstream grinding and process equipment selection for tighter design-to-operation integration.
With 2,428 tag-matched Product/Projects items in our database, Weir’s cluster of recent announcements on mills, water management, and digital tools signals that it is targeting full flowsheet influence in hard-rock operations rather than remaining a niche comminution OEM in Australia and other regions.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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