Freeport Indonesia’s Grasberg Mine is the world’s largest gold mine and third largest copper mine, the scale of which is so big that the mile-wide open pit is clearly visible from space.
The mine is situated in one of the most inaccessible and unforgiving locations on the planet…a place we now call home. The abundance of work here is the reason behind our move to this remote but spectacular part of the West Papuan jungle. Indeed, the company-owned town we live in, Tembagapura, literally means Copper Town (tembaga = copper, pura = town) in Indonesian.
The mining operations up here encompass many forms, however Grasberg relates solely to the Open Pit mining operation. This week, I was lucky enough to be invited to visit the pit on a private tour and to have my visit coincide with fabulous weather. Climatic conditions can be a little unpredictable when you’re 4,285 metres above sea-level!
Firstly though, a little history to set the scene. Prior to the discovery of Grasberg, operations at its small predecessor Ertsberg (Dutch for ‘Ore Mountain’) carried on for more than 15 years, oblivious to the fact that right next door, less than 3 km away, lay the world’s largest gold and copper deposit. Up until 1988, this super-sized treasure was just another ‘Grass Hill’, the Dutch translation of which led to the mine’s eventual name, Grasberg.
There was however, nothing simple about accessing the wealth contained beneath the soil. Ertsberg was tiny in comparison, in fact all of its equipment and workers were transported to that mine via an aerial cable tram system which required that all heavy equipment was disassembled at one end before being reassembled at the other. This existing transportation system simply would not cope with the demands of Grasberg. So, thanks to the fearless ambition of one Indonesian man and his little dozer, the HEAT (Heavy Equipment Access Trail) Road was born. One look at these pictures and you can see, this guy had a seriously strong constitution!
All vehicular access to the Grasberg pit is now via the cliff-hugging 11km long HEAT Road which rises in elevation by 2000 metres from start to finish with some fairly steep grades and relatively narrow tunnels along the way. It has to be, hands-down, the most stunningly beautiful haul road on the planet, flanked by dense jungle and picturesque waterfalls the entire way up. I was more than happy to let my guide do the driving, this is seriously challenging terrain, especially when the clouds roll in and torrential rain takes hold!
The cable tram system is still in full use, transporting smaller equipment, supplies and up to 100 people at a time from the milling area to the mining area quickly and effectively – it traverses a 700 metre high cliff in under seven minutes. Not to be attempted with a stuffy head!
Down in the pit, Grasberg operates a truck and shovel extraction methodology on a massive scale. The open pit produces around 140,000 tonnes of ore per day, using machinery from its fleet of around 150 dump trucks and 20 or so shovels. Most of the trucks used in Grasberg are 300 Tonne capacity and, as usual with photos, it’s hard to get some perspective. One thing is certain though, these massive machines look no bigger than ants when viewed at the bottom of the pit.
Once the overburden and ore are extracted from the pit, they are crushed and transported along a staggering network of surface and underground conveyors and vertical ore passes for further processing. Many of these systems pass directly through the massive mountains surrounding the mine site. I’m looking forward to visiting the mill, where secondary crushing, treatment, extraction and concentrating occurs and to understand how the final concentrate slurry is transported to the port at Timika for export. Fascinating stuff so stay tuned for more on that.
Now, I’m no rock doctor, but some of the geologic features of the pit and its surrounds are truly extraordinary. On one side of Grasberg are rare equatorial glaciers framing Puncak Jaya (Indonesia’s highest peak and one of the world’s ‘Seven Summits’ mountaineering challenges). On the other side, picturesque snow-capped mountains join with plentiful limestone deposits which are mined and processed into lime on-site. There are areas of magnetite (rendering parts of the pit wall highly magnetic), a significant amount of sulfur (resulting in the occasional whiff of rotten egg gas) and also a surprising amount of silver to complement the aforementioned copper and gold.
Everywhere you look up here at Grasberg results in fascination. From the seemingly unconquerable terrain, to the immense scale of the operations and the stunning beauty surrounding the site, Grasberg is awe-inspiring on every level.
This is the first in what I hope will be a series of tours of Freeport’s operations for me up here. There are a staggering number of underground operations either currently producing or under development, preparing to take over when Grasberg ceases production in a year or so. The Concentrator Mill area, where John works, is also contemplating massive expansion plans and I’m keen to some day see the port facilities where the concentrate leaves Timika for it’s various domestic and international customers.
So there you have it – Grasberg Mine – our reason for being up here in the jungle.
Until next time,
(See you later)