Management factored in a possible move into LTCC mining years ago during the planning phases for the pioneering Gunnedah Basin underground operation.
The Bucyrus (now Caterpillar-branded) longwall equipment used at the mine was ordered at least partly on the basis that it could be retrofitted with LTCC technology.
There are production and cost incentives offered by the effective use of LTCC technology which would extract the full length of the 9m-plus seam that the existing longwall cuts the bottom 4.2m from.
Yet safety considerations have weighed into a management rethink on LTCC.
“A decision was made during the quarter to pursue the feasibility of extending the longwall face to 400m in lieu of top coal caving as the superior optimisation path for Narrabri,” Whitehaven said in its quarterly results yesterday.
“The key attributes of a wider longwall face compared to top coal caving are lower operating risk, higher incremental production and reduced underground development, all of which can be achieved for a similar capital cost.”
While there was no update on what additional planning department consent has been sought for the strategic change, widening longwall panels to 400m from existing widths of 295.6m is a 35.3% gain that will need considerably more powered roof supports to achieve.
The mine is already well on the track to exceeding its nameplate capacity of 6 million tonnes per annum by a fair margin.
In the September quarter run of mine production reached 2.82Mt – 53% higher year-on-year. Saleable coal production was 1.82Mt – a 59% increase year-on-year.
Both results were new quarterly production records for the mine. An underground development quarterly record was also set with 6158m of main road and gate road development clocked up.
“These underground development and longwall production results achieved in recent months arguably place Narrabri in the top three longwall mines in the country for both longwall and development productivity,” Whitehaven said.
The introduction of longwall automation technology at Narrabri helped lift productivity.
“During the quarter longwall control systems were upgraded and processes were improved,” Whitehaven said.
“By implementing the upgraded software, full shearer automation has been attained. As a result, longwall productivity and horizon control have improved significantly and this improvement is expected to be sustained.”
Peabody Energy’s North Goonyella longwall mine is the most recent Australian operation to deploy LTCC technology. Australia’s pioneering LTCC mine, the Austar operation in the Hunter Valley, was set back by a wall collapse which killed two miners in April.
Mining of Narrabri’s underway third panel is scheduled to finish on October 21 with the fourth panel expected to start up six weeks later in December.
