The New South Wales’ mine has been experiencing problems since late September when workers tried to mine through a faulted area on the longwall face. Conditions on the face deteriorated and an “extensive roof fall” occurred.
Centennial said that since October 7 the mine had made encouraging progress on consolidating and stabilising the faulted area, which included injecting polyurethane resin into surrounding strata. However, remedial work has been slower than the company expected.
On October 7 underground employees were withdrawn from the mine due to an unstable underground atmosphere which arose from a higher than usual gas content.
On Tuesday, similar atmospheric problems re-occurred and the miners were withdrawn again.
Centennial said local management were concentrating efforts to ensure the affected area, in a localised part of the old underground workings remote from the current longwall face, was made permanently stable.
Stabilisation will involve injection of inert gas to the affected area, which started yesterday.
Centennial has also brought in independent experts to carry out further analysis of the faulted area to assist mine management to mine through the fault.
This month Centennial said delays with mining through the faulted zone would result in a 15% shortfall of budgeted mine production.
The company did not elaborate in its latest market release on whether recent delays would exacerbate the shortfall.
In the 2004/05 financial year Newstan produced 2.88 million tonnes.