Published in September 2007 Australian Longwall Magazine
Near Emerald in Queensland's Bowen Basin, Kestrel began its mining life as the Gordonstone Mine in 1992. Since then, the longwall has been churning the 3m-thick German Creek seam to produce an average of 4Mtpa of high quality coking coal.
Kestrel took out fifth spot in last year's longwall production rankings, with 4.48Mt run of mine coal, consistent with 2005. But Kestrel general manager Tony Lennox says management plans to increase output by widening the longwall face to 375m in the 400 series blocks and extract the remaining 140Mt of coal in the mining lease.
Since 2004, Kestrel has been mining the 300-series blocks, where longwall blocks are 250m wide and about 4km long.
Lennox told Australian Longwall Magazine the mine has two complete longwall units, operated alternately to enable continuous production without the typical ramp up and down associated with traditional longwall moves.
The longwall system comprises two DBT Electra EL 3000 shearers and 292 Joy 2-leg chock shields with a 2.3m-3.4m working range and PM4 controls.
A 250kW Joy Mining beam stage loader and DBT SK11-18 250kW coal crusher are also at work on the longwall face. The clearance capacity of the trunk and main gate conveyors is 5000 tonnes per hour.
"Kestrel has recently achieved around 80 metres of longwall retreat over five shifts. This is very encouraging and a glimpse of the future," Lennox said.
"Development activities involve approximately 15 kilometres of advance drivage conducted by three Voest Alpine ABM20-S1s, a Voest Alpine ABM20-S2, three Joy 15SC shuttle cars and 16 miner-mounted Cram Hfxbolters."
Feasibility studies into the Kestrel mine extensions began in 2006, and include plans for new drifts to access underground, new administration buildings, change rooms and an access road to the mine. Upgrades to Kestrel's coal handling and preparation plant have already started, and will deliver additional coal recovery.
Rio and local stakeholders consulted the community on the potential effects of the extension project. The traditional land owners, the Kangoulu people, were closely involved with cultural heritage work on the mine's extension into the 400's surface lease areas.
Kestrel mine extension general manager John Vale said the new longwall operation will include the latest technology conveyor belt systems and high efficiency electric motors to reduce noise and energy consumption.
"The team is also investigating ways to reduce water consumption through recycling," Vale said.
The Rio team has been working together with Kellogg Brown & Root on the expansion's planning and design.
"Kestrel's world class seam, low gas regime, minimal faulting, gentle dips and a low stress environment make it ideally suited for safe, high production underground mining," Lennox said.
