The Argyle Diamond mine in the isolated Kimberly region works in some of the hardest rock in Australia.
Contractor, Rock Engineering, operates a fleet of surface drilling equipment that includes the Atlas Copco ROC F9, specially designed for open pit work.
According to supervisor John Ivanovski the versatility of the ROC F9 enables it to be used for cable bolt holes as well as pre-splitting.
Now the company has followed up with a ROC L8 to drill dewatering holes. At a 5º-upward angle, the rig is achieving 150m holes and 200m long holes drilling vertically.
The rig uses a 5" hammer, 89mm drill pipes and 140mm bits. The carousel has been modified to allow for re-load of pipes every 48m.
Rock Engineering says it values the service availability in this remote location.
“I rely on being able to call the Atlas Copco fitters for advice and we are visited regularly on site,” Ivanovski says.
Another hard rock user of Atlas Copco rigs is the Sunrise Dam mine, 50km south of Laverton in Western Australia.
This has gone through numerous upgrades and expansions since it opened in 1997 and has now reached a depth of 460m. However, with increasing pit depth output began to decline to about 1.4 to 1.6 million cu m a month in early 2002.
But in November of that year, mining contractor, Roche, which operates a range of large trucks, excavators and drill rigs at the site, introduced the Atlas Copco ROC L8.
This equipment was described as a “new breed of DTH crawler” because of its ability to perform all four tasks of pre-split drilling, production drilling, in-pit grade control (reverse circulation) and dewatering holes (pit stabilisation).
Traditionally, individual rigs have been required for each of these functions.
Commenting on the machine, Roche plant manager John Hawkes says relative to its size, the rig is achieving metre-per-hour rates that are equivalent to those of Roche’s larger machines.
“We were sceptical at first, but the ROC L8 is easily meeting those rates,” Hawkes says.
The Sunrise operators also comment favourably on the rig’s tramming ability, which enables them to move the rigs quickly and safely around the site.
According to Atlas Copco Construction & Mining Australia product manager, surface drilling equipment Lars Senf, the Australian drilling contractor market is among the most demanding in the world.
“Not only is the competition tough, but the working conditions are among the toughest I have ever come across,” Senf says.
“In summertime, the contractors are facing ambient temperatures above 55ºC in the pits and, at night, the pit walls that have been heated up during the day now reflect the heat. Then there is the remoteness, and the fact that most mines run a 24/7 operation.”
Senf says Atlas Copco has recognised the need for a rig that could handle these sorts of conditions and, together with Roche Mining and Rock Engineering, it customised the rigs to suit the contractors’ needs.
“In the first case, we converted two ROC L8s to allow them to do RC drilling for in-pit grade control. In the second, the rig was modified to allow for holes to be drilled to greater depths than 150m vertically as well as horizontally,” he says.