The 7000-tonne Bucyrus 8750-63 dragline has arrived at the Ensham Resources-operated mine after a weeklong, 12km trek from a purpose-built construction pad.
It is expected to move 20 million bank cubic metres (Mbcm) of overburden this year and 28Mbcm per annum from next year, and will allow Ensham to stand down part of its higher cost truck-and-shovel fleet.
Its purchase of the massive dragline is symptomatic of a wider swing back to dragline overburden removal in the Bowen Basin after many operations brought in contractors with truck and shovel and/or hydraulic excavator fleets during the 1990s to mine waste.
Ensham general manager operations Peter Westerhuis said the dragline replaced a fleet of smaller shovels uncovering coal in a new area of the mine where the coal seam was deeper beneath the surface.
“That’s [forecast material movement rate] more than two of the mine’s existing draglines put together and underscores the sheer size of the Bucyrus 8750-63 and its 110 cubic metre bucket,” he said.
Westerhuis said the decision to build the dragline was made in 2004 to improve Ensham’s ongoing sustainability and competitiveness in the global steaming coal market by reducing overburden removal costs.
“We’ve had an unusually high dependence on truck and shovel operations to meet our production targets over the past couple of years but as the coal gets deeper, this method is proving inadequate and too costly in moving the sheer volume of overburden which needs to be moved to access the coal,” he said.
“We have started planning and discussing with our principal contractor the reduction of truck and shovel fleets that the dragline will replace over the course of 2007 to allow them to redeploy those resources elsewhere.”
Westerhuis said demobilisation of truck and shovel fleets would occur gradually, starting next month and winding up around May as the new dragline was properly bedded down.
This would reduce the number of contract truck and shovel fleets from eight to five in total.
Each fleet employs some 35 people including fleet managers, machine operators and maintenance support.
“We hate to see good people go, especially in a time of severe shortages, as we are likely to require their services again in the future. However, flexibility is part and parcel of using contractors and I’m sure they will be readily deployed on other projects until we move into our next expansion phase.”
A severe and growing shortage of experienced dragline operators is a constraint for other operators looking to increase dragline usage to lift production at a time when costs of fuel, truck and shovel drivers, tyres and equipment are all rising.
Ensham is employing an additional 20 people full-time this year to operate and maintain the new dragline.
The company wants to grow saleable thermal coal output via new opencut and underground developments to 20 million tonnes per annum. It is currently producing 8-9Mtpa.