The expanded use of Xstrata Technology’s IsaMills^TM will support a planned increase in production at Xstrata Zinc’s McArthur River Mine (MRM) in Australia as part of its Phase 3 development project. Xstrata Technology General Manager – Mineral Processing, Lindsay Clark said MRM is a leader in the use of IsaMill technology and its continued development from regrind applications to mainstream coarse grinding applications.

“IsaMill technology has enabled Xstrata Zinc to process the ultra fine grained ore at MRM,” Clark explained.

The MRM Phase 3 development project is targeting increased mining capacity from 2.5 Mt to up to 5.5 Mt/y from the open pit, producing an average of 380,000 t/y of contained zinc. Production will increase from 360,000 t/y (dry) of bulk concentrate to 800,000 t/y (dry).

As part of the expansion, MRM has ordered two additional M10,000 IsaMills, to complement the eight existing IsaMills, which are used in both the primary grinding and regrinding circuits of the processing facility.

Xstrata Zinc Australia Chief Operating Officer Brian Hearne said the latest increase in IsaMills follows a similar expansion in 2007 which supported a 39% increase in production capacity at that time. “We find the IsaMills to be simple and functional from an operator’s point of view which for us supports low cost and reliable production,” Hearne said. “The IsaMills presented the best option to get the volumetric efficiency, grind sizes and energy efficiency we are now looking for in the Phase 3 development project.”

IsaMills were developed to be much more energy efficient than other grinding technologies and to improve flotation recovery due to inert attrition grinding. The two new M10,000 IsaMills will increase primary grinding capacity at MRM by grinding from 150um to 45um (P80). They will take MRM to a complement of ten IsaMills, six M3000s and four M10,000s, undertaking a range of ultrafine, fine grinding, and coarse grinding duties.

Xstrata Technology will supply the IsaMills for the project, as well its proprietary IsaCharger^TM, for controlled addition of fine ceramic media to the mills. The mills are expected to be commissioned in the second half of 2013.