Century

The MMG owned Century Mine in north west Queensland, that is the world's largest open pit zinc mine, has operations in two locations. The mine itself along with its processing plant is located at Lawn Hill, 250 kilometres north west of Mount Isa, and a concentrate de-watering and ship loading operation that is located at Karumba Point on the Gulf of Carpentaria 304 kilometres north east of the mine site. The concentrate produced at the on site processing plant at Lawn Hill is pumped along a 304 kilometre underground pipeline to the Karumba port where it is de-watered before being taken by ship 45 kilometres off shore to be unloaded onto bulk ore carriers that take to product to various locations around the world. Zinc production at the Century Mine for 2013 is expected to be between 480,000 and 490,000 tonnes of zinc concentrate.

The Century Mine Resources are Expected to be Depleted by 2016
The Century Mine that produces zinc, lead , silver and cadmium is expected to deplete its resources in 2016 and is currently in a transitional period of rehabilitation. MMG have awarded this stage of operation to mining contractor NPC who are to complete certain earthworks in readiness to eventually return the site to its use before mining which consisted of native habitat and cattle grazing.

Concentrate is Taken 45 Kilometres Offshore for Loading Onto Moored Ore Carriers
The Century Mine currently employs 264 contractors and 761 employees on site who fill one ore carrier a week with zinc and lead concentrate to be smelted by its various customers in Asia, Europe and Australia. The concentrate sent to the port is de-watered and stockpiled in a storage shed while waiting to be exported, however, because of the shallowness of the water in the Norman River channel and the lower reaches of the Gulf of Carpentaria generally, MMG have to use a transfer vessel, the MV Wunma, to take the concentrate 45 kilometres out to sea where moored ore carriers wait to be loaded. The MV Wunma, that has been specially built to safely navigate the shallow waters, takes around 12 hours to load, travel the 45 kilometres to the waiting ship, discharge the concentrate and return to Karumba. It operates 24 hours a day, depending, of course, on weather conditions and the tide.

Century Mine Open Pit is Mined in the Conventional Manner
Conventional open pit mining methods are used at the Century Lawn Hill ore body that is rather flat and extends over an area of 2.5 kilometres by 1.4 kilometres and to a depth of 336 metres. Commercial production began in 1999 with full production being reached by 2002. Equipment at the site consists of graders, dozers, 240 and 170 tonne haul trucks, a fleet of Liebherr shovels and other ancillary machinery.

Mined ore is Stockpiled in Readiness for the Wet Season
Mined ore is stockpiled on the ROM (run of mine) pad and fed into the concentrator for processing when needed. The ore is loosened from the deposit several times a week through drilling and blasting. The loosened material is then shovelled into the haulage trucks and taken to the ROM pad. The ROM pad stockpile is purposely built up during the dry season to allow for the long wet season to ensure production can continue unabated during periods of heavy rain.

The Century Mine operates 24 hours a day, seven days a week. Maintenance workers and heavy vehicle operators work a roster of either eight days on and six days off or seven days with seven days off.