THOUSANDS of abandoned bore holes left puckering Queensland's landscape after 170 years of coal mining may now be repaired.
This week, the Queensland Government unveiled plans to ensure these leftover bores and any gas leaking from them were safe.
On Friday, the government conceded it had little idea of just how many coal exploration drill sites it had to worry about.
A spokesman for Mines Minister Andrew Cripps said coal mining throughout the state since the 1840s meant the scale of the issue was difficult to quantify.
"It is currently not possible to identify the precise number and location of all historic coal exploration bores in Queensland," he said.
"In many cases, the companies that drilled them no longer exist."
These days, such holes must be plugged and rehabilitated but those drilled decades before could still pose some danger.
The government was pushed to create the guidelines after a long-abandoned bore near Kogan, west of Dalby in south-west Queensland, was found to be leaking methane.
Since the gas leak was discovered, the site has been repaired, filled with concrete and capped with the help of departmental and industry inspectors.
The government's latest plan will be guided by peak bodies for Queensland's mining industry and Australia's gas sector.
On Wednesday, Mr Cripps said while any risk posed by these discarded sites was low, the government needed to know what to do if a problematic site was reported.
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