Highly mineralised ultramafic rocks lie beneath the laterite deposits along the Western Range. The predominant rock types within the ultramafics include harzburgite, serpentinised harzburgite, peridotite and serpentinised peridotite.
Mineralisation is predominantly found to occur at the base of the Fe laterite, at the top of the saprolite and in magnesium-rich clays within the ultramafic saprolite.
Reserves and resources
The Agata North nickel mine is estimated to contain proven and probable ore (limonite and saprolite) reserves of 6.79 million dry metric tonnes (Mdmt).
As of April 2013, the mine was estimated to contain measured and indicated resources of 33.94Mdmt at a grade of 1.1% nickel, while the inferred resources were estimated at 2Mdmt with a nickel grade of 1.04%.
Mining activity at the Agata mine
Conventional load and haul method will be applied at the DSO mine. The ore will be hauled to the stockpile area using trucks, where it will be blended and dried before transporting to the loading facility.
The blended and dried ore will be trucked to a port loading facility at Payong Payong Bay and directly unloaded onto barges.
The mining fleet consists of Isuzu Giga vehicles, Volvo FMX trucks, 36t hydraulic excavators, 30t capacity articulated trucks, front end loaders and 18t capacity on-highway trucks and other ancillary fleet consisting of dozers, graders and water trucks.
The Agata nickel processing plant is expected to commence production in 2016 and is expected to have a lifespan of 20 years. The laterite material consisting of limonite and saprolite will be combined with sulphuric acid at the processing plant, and the resultant intermediate nickel product will be either sold as it is or further processed to produce metallic nickel.
Details of the Agata pilot plant
A pilot plant operation is being conducted at the Agata mine. Approximately 30t of ore mined from a variety of test pits covering the Agata ore body was tested at the Beijing General Research Institute of Mining & Metallurgy facility in China.
The ore was leached through primary and secondary leaching methods and approximately 8,000l of pregnant leach solution was recovered from the pilot plant campaign. The leach solution was recovered by a counter current decantation circuit.
The leach solution was shipped to the TVIRD’s metallurgical testing facility in Manila, Philippines. The solution was further processed, resulting in a nickel hydroxide product containing 53% nickel.
Construction and infrastructure facilities
Major works at the Agata mine will comprise the construction of haulage roads, administration facilities, accommodation camps and a port facility.
Access to the mine from Butuan City or Surigao City is provided via the Pan-Philippine Highway and other municipal roads.
Power required during the mine construction will be provided through 150kV diesel generators. The assay laboratory and shipping office at the port loading facility will be powered by a 50kVA generator. Water required for the mine will be sourced from Mantiawas Creek.