While most construction trucks spend their days transporting plain, old-fashioned dirt, articulated haulers at a mine in Angola, a nation in southwestern Africa, are handling pricier cargo – diamonds.
The Luzamba diamond mine produced 620,000 carats in 2004, but mine owners are determined to increase production and recently purchased eight Volvo A25D articulated trucks to help meet their goal.
In order to obtain a larger amount of diamonds, the Kwangu River (which contains the diamond-rich deposits) must be diverted. This is achieved by altering the flow with specially dug channels, typically about a mile in length. Afterward, each riverbed dries out and the deposits can be collected. This process of ‘mining out’ takes about four months for each 1-mile section, and then the river will be put back into its natural state.
In addition to the haulers, the mine owners bought two EC290B1c excavators and three L150E wheel loaders. They already own 23 A25 haulers from B and C generations. The A25D haulers are fitted with tailgates to help prevent the wet, diamond-rich material from flowing off the back and increase the normal payload by a half ton. Mine operators also use a substantial fleet of Volvo tipper trucks.
All this equipment works together, but the hauler is the primary machine. The process begins with excavators feeding the haulers, which stockpile for the wheel loaders. The equipment must deal with steep slopes of dry shifting sand as well as muck resulting from eight months of rainy weather per year.
“There’s no secret to what the weather is going to do,” said Robert Jones, general manager of the mine. “We just have to set up operations so that production continues.”
This preparedness extends to parts stocking. The mine stocks many major components as well as consumables. Because the mine is more than 1,000 miles from its supply point in Luanda, Jones said he standardizes the fleet as much as possible so that parts stockholding doesn’t get excessive.
Hauler drivers must remain alert to changes in roads at all times since the river is constantly being diverted and extraction work is always going on. One A25C driver who didn’t notice the road had changed drove straight into the river. The operator was fine, although crocodiles and hippos occupy the Kwangu River. The truck, on the other had, was submerged until the river was diverged a month later. After it dried out, the hauler started without any problems.
Diamonds are not only extracted from river beds, but also from river banks where diamond-rich deposits are sometimes found as deep as 1 / mile. In order to find diamond-rich spots, the mine executes rigorous test cores. “After awhile you can have a good eye where there are likely to be diamonds,” said Jones, who has spent decades searching for the precious gems. “But we’re not infallible, so we test the site systematically so as not to miss any.”
After the alluvial material is extracted it enters the diamond factory, where it is crushed, sieved, separated and sorted. Jones said people do not actually touch the diamonds during this process. “To me it’s just another product,” said Jones. “I’ve mined for coal and copper and I’m no more excited about diamonds than I am about coal!”