Luikonlahti Mill

The Luikonlahti processing plant is located some 45km via sealed road from the Kylylahti deposit. The mill was constructed in 1968 to process ore from the Luikonlahti copper-cobalt-nickel-zinc deposit. It operated for 15 years and processed 7.7Mt of copper-cobalt-nickel-zinc ore virtually identical in its grade and metallurgical characteristics to the Kylylahti deposit. The photographs above and below give an aerial view of the extensive infrastructure purchased and the interior of the mill and flotation hall.

Luikonlahti Mill and Tailings Area

Secondary Grinding Mill

Talc Flotation 2006

Altona Mining has undertaken engineering due diligence, environmental due diligence, legal and commercial due diligence. In addition, the suitability for the mill to treat Kylylahti ore was assessed based on the extensive metallurgical testwork and process engineering work undertaken during the Kylylahti Definitive Feasibility Study, the Feasibility Study on the Luikonlahti plant completed by Belvedere in 2009 and the prior operating history of the facility. The equipment at Luikonlahti was found to be appropriate for treating Kylylahti ore. The facility was designed to treat ore with a Ball Mill Work Index of 14.9kWh/t and a grind size of 78 microns. The Ball Mill Work Index for Kylylahti ore is 14.9kWh/t and the optimum grind size as per the Definitive Feasibility Study is 100 microns. A finer grind of Kylylahti ore would only improve metallurgical performance.  

There are two existing mills, a primary rod mill and a secondary ball mill which as currently configured provide a throughput of 350,000tpa. The original circuit was a rod mill and two pebble mills. Most equipment to re-instate the second pebble mill remains onsite. The mills have sufficient motor capacity such that re-configuration of the circuit as ball mills rather than rod mills can easily achieve a throughput of 500,000tpa or more. Belvedere’s Feasibility Study addressed the capital and operating aspects of such a plant upgrade.

Altona Mining engaged SWECO Industry Oy to audit the Feasibility Study on the refurbishment of the Luikonlahti mill completed by Belvedere in May 2009. SWECO commented that the plant was structurally sound and in good condition. SWECO recommend a cost allowance of €6.35m (A$10.2) for refurbishment, automation, increasing tailings dam capacity and reconfiguring tailings decant. Altona estimates some additional expenditure will be required to increase concentrate filtration capacity.