Within four years production from the expanded project is expected to increase from current levels of 1.6Mtpa to 3Mtpa, the Tahmoor North and Bargo leases would begin in earnest.
New South Wales-based Austral owns and operates the current 1.6Mtpa Tahmoor longwall mine in the NSW Southern Coalfield. For the March quarter, ROM production from Tahmoor amounted to 328,000 tonnes, slightly down on the previous quarter because of a localised fall on the longwall face in February.
To increase production rates and improve mine productivity, maintenance tasks and set up work has been scheduled for weekends, to be carried out by weekend maintenance contractors from April/May.
During the quarter, 1363m of development was driven, a vast improvement on the last three quarters where "grunching" techniques were implemented to develop through an extensive zone of tight gas. Improved gas conditions in the remainder of the longwall 19 maingate panel are expected to allow a significantly better development rate.
Over 11,400m of gas drainage drilling was completed during the quarter. Austral said it has been able to maintain its standard of fully drilling one and a half longwall panels ahead of mining. This is expected to be progressively increased.
“Improved gas composition in longwall panel 20 has enabled drill hole spacing to be increased to 20 metres from the standard eight to 12 metres in longwall 19. These improved conditions will markedly improve drainage rates and lower drilling costs.”
The feasibility study undertaken by International Mining Consultants (IMC) on future development at Tahmoor was completed during the quarter. Austral said the results indicated “exceptional returns on mining the Tahmoor North and Bargo leases.” IMC has been retained to prepare the detailed mine development plan.
Presenting a paper at the Longwall Mining Summit in Yeppoon last month, Austral managing director Ugo Cario said the mine plan was a brownfield development at a capital cost of around $88 million or $51.70 per tonne. The majority of the capex will be to buy a new longwall.
“The remaining capital will be spent on upgrading the continuous miner development fleet, refurbish and install new main trunk belts to a 3,300 tonne capacity and upgrade the drift winder and washery to accommodate higher throughputs. Expenditures on the latter start in fourth quarter this year with contractors undertaking main road refurbishment and installation,” Cario said.
The project assumes a twenty year mine life, excluding the Bargo west deposit. Roadway development will proceed on an in place basis rather than place changing due to a laminate roof expectation. Roof support will be 4-6 bolts/straps at 0.75m centers. Cario said cash costs were expected to be in the lower quartile.
On the marketing front, Austral’s price negotiations with Japanese, German, Indian and domestic customers were concluded during the quarter with an average increase of 23% in coking coal price. Austral said it has diversified its markets reducing reliance on north Asian customers. Increased tonnages go into the German market while BHP's Port Kembla steelworks will take 200,000t.
