All the mines lifted output from 2004 bar Newstan, but the shortfall was more than made up by production from new mine Mandalong, which contributed 2.65Mt and rated as the second highest Centennial producer despite having a few weeks handicap with a January 2005 start-up.

Centennial expects Mandalong to produce 4 million tonnes per annum in 2006 and beyond, lifting the company's production by 25%. The output in 2005 was down on the 3.5Mtpa expectations Centennial released during early 2005.

For the December quarter Mandalong returned a record quarterly production of 998,681t – despite operating with only one coal clearance system while a second system was completed and commissioned. The company also reported a weekly record during February this year of 114,000t.

During the December quarter the mine also widened the longwall to 160m. The longwall operates at 4.8m, making it one of the highest operating faces in NSW.

Centennial’s biggest producer during 2005 was Springvale with 2.79Mt. Springvale lifted output by almost 300,000t from 2004 to 2005.

Late in the year the mine benefited from efficiencies gained from the first of the wider 305m longwall panels and an upgraded armoured face conveyor.

Springvale is relocating its longwall to the first of its longer blocks, which are 3.6km long by 305m wide and contain approximately 5Mt of coal. During this changeover, Newstan will upgrade its coal clearance system, the longwall crusher and stage loader and Centennial expects big things from the mine this year and beyond.

“The main contributors to second-half and future profitability are expected to be Tahmoor and Mandalong, together with Clarence, Springvale and Angus Place," managing director Bob Cameron said in February this year.

Despite the plethora of much-documented problems with the company’s Newstan mine in 2005, the longwall still managed to sneak into third highest company longwall producer spot with 2.38Mt.

Centennial hit a major snag in late September 2005 when the Newstan longwall struggled to mine through a faulted zone. The two-month delay in production lost the mine at least 450,000t, or 15% of projected annual output.

The longwall has now successfully mined through the fault zone and has been operating normally since December 2005.

“Although Newstan is now operating in normal conditions, the physical impact on the mechanical integrity of the old armoured face conveyor continues to impact the mine's performance, such that Newstan is not expected to make a contribution to group profitability until it commences mining on its next longwall block. A new AFC will be installed during the next longwall changeover scheduled to commence in April 2006," Centennial said February.

Newstan is one of five other operations Centennial is currently considering selling so it can concentrate on its larger mines. Other mines under review include Awaba, Myuna, Mannering and Berrima.

Centennial will look at retention, partial sale or full sale of the mines.

“We believe there are significant benefits in concentrating our efforts on larger, world-class mines which have the capacity to become the engine of the company's long-term growth. Accordingly, we are assessing whether we should re-balance our portfolio of mines," Cameron said.

Newstan, along with the other smaller mines, may well be sacrificed so Centennial can add value at operations such as the new Anvil Hill opencut and Mandalong.

Centennial is expected to distribute information memorandums on the five mines by mid-April.

Centennial Coal’s longest operating longwall Angus Place, which began operations in 1979, performed satisfactorily during 2005 with output of 2.23Mt.

The mine had an up and down year with an excellent June 2005 quarter following an upgrade of its conveyor infrastructure last year. However, the mine ran into problems late in the year and early this year with a longwall changeover, completed in early January, taking a little longer than planned due to poor floor conditions in the access roadways, hampering relocation.

However, during the longwall changeover, significant upgrades were undertaken to the coal clearance system and longwall equipment, which Centennial says will provide improved reliability and production capability.

Last in the Centennial output stakes was the fairly recently acquired Tahmoor mine which produced 1.96Mt.

Tahmoor’s mine production has steadily improved following Centennial’s takeover of the mine in April 2005.

Tahmoor ended 2005 on a high, producing 640,000t for the December quarter, 9% higher than its previous best under Centennial management and approaching the mine's record quarterly production of 686,000t.

Work continued to progress the long-term ventilation of the mine, Centennial management already achieving a 250% improvement in airflow to the longwall face. A secondary fan was installed during February 2006 and a new mine fan will be installed in the 2007 financial year to lift production towards the target of 3.5Mtpa by the 2009 financial year.

Tahmoor management has also "designed out" some inherent engineering problems on the longwall equipment – overall equipment availability has now risen above 95%.

Like Mandalong, Clarence, Springvale and Angus Place, Centennial expects Tahmoor to become a big contributor to company profitability into the future.