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Santa Rita Operations

Mirabela’s primary focus is the 100% owned Santa Rita nickel sulphide deposit, located in Bahia, Brazil. This is the world’s largest greenfield nickel sulphide discovery in over a decade.

The mine is comprised of an open-cut mine and a concentration plant to produce a mixed nickel-copper-platinum-cobalt sulphide concentrate for sale and shipment to third party smelters.

Construction of the mine and processing infrastructure is complete, commissioning is underway and delivery of nickel concentrate to Votorantim has commenced. 

The Caterpillar mining fleet is owner-operated and financed by a fleet financing agreement with Caterpillar Financial Services. Bulk mining methods are deployed using 100t and 150t trucks (Caterpillar 777 and 785s) combined with Terex O&K RH90 and RH120 excavators and Caterpillar 982 loaders.

Ramp-up to the plant's current name-plate capacity of 4.6Mtpa is expected during Q2 2010 and Mirabela's production guidance for 2010 is forecast at between 10,500 to 12,500 tonnes of nickel in concentrate. 

Nickel processing will be via a conventional flotation circuit, using proven sulphide flotation methods as follows:

• Primary crushing down to minus 220mm with a Metso gyratory crusher 1,500tph (about 10Mtpa)
• Grinding to a P80 of 125µm with an Outotec 30' SAG mill, 20' Ball mill and an HP400 pebble crusher rated at 575tph. Throughput is expected to be increased to 800tph with the addition of a second 20' ball mill and pebble crusher in 2010
• Flotation of sulphides with a conventional Rougher, Scavenger and Cleaning process using Outotec flotation tanks as follows:
  • 12 x 160m³ cells for roughing and scavenging (with foundations for 4 additional cells if required)
  • 9 x 70m³ cells for cleaning (with foundations for 3 additional cells if required)
  • 4 x 30m³ cells for recleaning (with foundations for 1 additional cell if required)
• Tailings thickening (tank capacity 800tph) and concentrate thickening (tank capacity ~50tph) are used to remove excess water from tailings and concentrate
• Filtering of concentrate (Larox pressure filter capacity 33tph)

The installation of a second ball mill will increase the mill's operating capacity to 6.4Mtpa and production of 26,000tpa of nickel in concentrate.

An operating licence has been granted for the Santa Rita mine and all plant facilities by the Brazilian environmental authorities.

The Company has agreements to sell 100% of production to two off-take partners until end 2014: Norilsk Nickel, the world’s largest nickel producer and Votorantim Metals, a Brazilian mining company with a smelter in Brazil. Half of the concentrate product will be trucked 1,350km directly to the Votorantim smelter in at Fortaleza de Minas, Brazil and the other half will be shipped to the Norilsk smelter at Harjavalta, Finland. Each partner will take 50% of all production and has provided US$50m in subordinated loans.

Santa Rita has excellent access to all key infrastructure and is located close to port and major service centres. Once in operation, Santa Rita will employ approximately 500 people directly and 1,500 people indirectly, the majority of whom will be from the nearby local communities.

Resources and Reserves

The Santa Rita mine is based on a world-class inventory of contained nickel resources, including 900,000 tonnes of open-pit and 690,000 tonnes in underground resources. It is a long life project, with 19 years of open-pit reserves and a low cost structure.

Santa Rita Proven and Probable Reserves
(As announced November 2008)

• Contained nickel – 726,000t (1,600 million lb)
• Strip ratio – 7.2 to 1
• Weighted average recovery – 70.2% Ni

The Reserve estimate is based upon the Potential Mill Feed Resource Estimate (pit optimised resource) announced in September 2008 as follows:

• Measured and Indicated Resource – 130mt grading 0.60% Ni and 0.16% Cu
• Inferred Resource – 20mt grading 0.60% Ni and 0.16% Cu
• Strip ratio – 7.6 to 1