Drilling with sharks

Drilling with sharks

Bringing an open-cut mine back into production after a 15-year shutdown is usually not a daunting prospect. But when the mine is full of shark-infested seawater, it’s a bit trickier.

On Koolan Island, off the coast of Western Australia, sharks swim in what was once a productive iron ore mine. When Australian mining giant BHP ceased mining operations on the remote island in 1993, it breached a cliff and flooded the main pit with 100 metres of seawater as part of the rehabilitation programme. Mt Gibson Mining bought the property in 2007 with the aim of resuming production. ROCK Australia Mining + Civil won the contract to restart the drilling.

To prepare for the ore mining, the seawater had to be removed from the pit and the walls stabilized. ROCK needed a drill rig capable of handling all the ground support functions from a floating barge and capable of being operated remotely in case the wall face showed signs of crumbling. It acquired a Sandvik DX800R, a hydraulic, self-propelled surface drilling rig with a unique 90-degree slew capability for drilling horizontal holes to stabilize the footwall.

After customizing the system to match the delicate surroundings, work began in earnest. The current footwall rehabilitation phase will be completed later this year.

“We believe this is the first use of remote control rigs in Australia, and operating those rigs from floating barges is almost certainly a mining world first,” says ROCK’s Mike Moore, who developed the plan to bring the mine back into production.