The mining area includes three major resource deposits to date. The size and position of the deposits are well-suited to conventional open pit drill and blast operations. The ore geometry results in particularly low stripping ratios, with 12 metre benches and a final pit wall slope approximately 48-50 degrees depending on deposit area selected for the proposed production rates.
Mining transport options to be considered during project development include
• bulk movement options such as trucking, in-pit crushing with conveying or trolley assisted haulage
• utilisation of waste in several alternative uses.
Processing
The Rönnbäcken deposits comprise nickel sulphides in serpentinized ultramafic rocks. The nickel sulphide minerals are predominantly pentlandite (38-40% Ni), nickel rich heazlewoodite (71-75% Ni), and some millerite (61-65%). The ores are also distinctive for the absence of iron sulphides (pyrite and pyrrhotite), allowing for efficient gangue rejection resulting in a very high grade of nickel in the concentrate.
Proven and conventional technology
Although the nickel content is low compared to existing nickel mines around the world, metallurgical tests carried out in the past were successful in producing a nickel-rich sulphide concentrate with much higher grade (25-35% nickel) than typical concentrates, using conventional ore dressing technology. The RNP flow sheet consists of crushing, grinding, flotation, and dewatering steps typical to Scandinavian concentrator operations. The conceptual concentrator design has been provided by Outotec (Sweden) AB.
Conventional crushing, grinding and flotation will be used to treat the ore in a simple flowsheet which will produce a high grade nickel concentrate product. Two processing lines will be used in grinding and flotation to facilitate high reliability in operations.
