A University of Queensland study has found that a single abandoned coal exploration borehole in the Surat Basin was leaking 235 tonnes of methane per year — equivalent to the emissions of 10,000 cars. The discovery has raised concerns about an estimated 130,000 legacy exploration boreholes across Queensland, many of which may have never been properly sealed.
A Hidden but Significant Emissions Source
Researchers Associate Professor Phil Hayes and Dr Sebastian Hoerning described the site as a “super-emitter,” calling their study the first long-term measurement of methane emissions from an abandoned coal exploration borehole. They noted that while most boreholes are unlikely to emit at dangerous levels, those that do could represent a major, unreported source of greenhouse gas emissions.
Importantly, the researchers emphasised that sealing the highest-emitting boreholes would be a cost-effective way to rapidly reduce emissions.
Legal and Regulatory Implications
For landowners, agribusiness operators, and investors, this research has legal and financial implications:
- Environmental Protection Obligations
Under the Environmental Protection Act 1994 (Qld), leaking boreholes can be classified as contamination or environmental harm. Landholders may have obligations to report, remediate, or manage these risks. - Disclosure in Property Transactions
Sellers of farmland or rural property may have disclosure obligations if a borehole is known to be leaking. Failure to disclose could lead to disputes or compensation claims from buyers. - Potential Liability and Costs
The cost of remediation or sealing could fall to the landholder. Investors should factor these potential liabilities into due diligence and acquisition budgets. - Insurance and Compliance Risk
Insurers may require evidence of proper borehole sealing or may exclude coverage for environmental damage caused by legacy infrastructure.
Commercial and Strategic Considerations
This issue is not only environmental — it can directly affect land value, transaction timelines, and development approvals. Commercially savvy investors and operators should:
- Enhance Due Diligence
Commission environmental searches and historical title checks to identify any legacy exploration boreholes on the property. - Include Contingencies in Contracts
Negotiate clauses addressing responsibility for sealing, remediation, or cost-sharing where boreholes are identified. - Adopt a Proactive ESG Approach
Addressing methane leaks can form part of an ESG (Environmental, Social, Governance) strategy, reducing carbon exposure and enhancing asset value. - Engage Early with Regulators
Voluntary reporting and collaboration with the Department of Environment and Science can mitigate penalties and demonstrate compliance.
Ensure Legal’s Perspective
This development underscores the need for thorough environmental due diligence in rural and resource-adjacent property transactions. Identifying and managing the risk of abandoned exploration boreholes protects both asset value and legal compliance.
Ensure Legal advises clients to integrate environmental and regulatory risk assessment into all acquisitions and long-term landholding strategies. Doing so now will minimise future liability, support sustainable farming and development, and position landowners to meet evolving environmental reporting standards.
