This article is 14 years old. Images might not display.
The major geological work undertaken last year not only updated geological modelling but included seam selection and mine layouts based on longwall mining methods.
“The new work has resulted in a reduction of underground resources, principally at Hunter Valley Operations,” Coal & Allied managing director Bill Champion said.
“Although underground resources have decreased, the company now has a much higher degree of confidence in the development potential of what remains a very large underground resource base.”
The revision cut underground mining resources to 125 million tonnes, all in the inferred category.
This is compared to the total of 477Mt of underground mining resources at the end of 2009.
But the mine also boasts 263.2Mt of marketable reserves of both thermal and met coal.
The Rio Tinto subsidiary did not reveal the marketable reserves specifically suitable for underground mining at any of its mines.
However, this was not the case for resources.
The Mount Pleasant project has 124Mt of met coal resources in the inferred category for underground mining.
The Mount Thorley mine hosts 81Mt of underground resources with 18Mt indicated and 63Mt inferred.
This thermal and met coal mine has 23.8Mt of marketable reserves, considerably less than the others in the Coal & Allied portfolio.
With 18Mt of open cut resources, the development of an underground operation could extend its mine life.
The associated Warkworth thermal and met coal mine holds 296Mt of resources for underground mining, including 86Mt indicated and 210Mt inferred.
At the Bengalla mine, which Coal & Allied equally shares with Wesfarmers (40% each), there are 35Mt of inferred resources for underground mining.
All these resources are prospective for met coal as opposed to the 137Mt of marketable thermal coal reserves which are slated for open cut mining.
Rio Tinto Coal Australia principal geologist John Bamberry compiled the underground resources component of the company’s year-end reserves and resources update.
Coal & Allied shares closed unchanged at $129.74 yesterday.
