WA DMPE issues Stop Work Order after satellite imagery uncovers unauthorised 23-hectare saline groundwater discharge

WA Regulator Issues Stop Work Order After Satellite Detection of Unauthorised Hypersaline Discharge

Western Australia’s Department of Energy, Mines, Industry Regulation and Safety (DEMIRS) has issued a Stop Work Order against a mining tenement holder in the Phillips River region after satellite monitoring exposed an unauthorised discharge of hypersaline groundwater that had been running for approximately two months before inspectors ever set foot on site. The discharge inundated 23 hectares of native vegetation and topsoil stockpiles that had been set aside for future rehabilitation works, and the operator subsequently admitted the release occurred because on-site retention facilities had run out of capacity.

This matters well beyond one tenement in the Phillips River area. It confirms that Western Australian regulators are now using remote sensing data, specifically Normalised Difference Moisture Index (NDMI) imagery, to detect environmental breaches retrospectively across entire tenement footprints rather than relying solely on physical audits or operator self-reporting. For environmental consultants, mining proponents, infrastructure developers and their legal advisers, the case is a clear signal that undisclosed discharges, dewatering overflows and unpermitted land disturbance are increasingly detectable long after the fact, even where no complaint has been made and no inspector has physically attended site.

For Australian environmental professionals advising resource, infrastructure or large-footprint development clients, this enforcement action reframes how compliance risk should be assessed at the planning, operational and closure stages of a project. It also raises the practical question of whether existing groundwater management and dewatering contingency plans are adequate if on-site storage capacity is exceeded during wet weather events or unplanned inflows.

How NDMI Satellite Imagery Exposed a Two-Month Discharge Timeline

DEMIRS inspectors identified the breach using NDMI satellite data, a remote sensing technique that measures liquid water content in vegetation and surface soils by analysing near-infrared and short-wave infrared reflectance. Changes in NDMI values over the tenement area showed surface inundation and vegetation moisture stress consistent with an ongoing discharge, allowing the department to establish that the unauthorised release had been occurring for roughly two months prior to the physical site inspection that triggered the Stop Work Order.

The affected area covers 23 hectares of native vegetation and topsoil stockpiles that had been retained specifically for future mine rehabilitation. Hypersaline groundwater discharged directly onto this land poses a compounding risk. It damages the structural integrity of stockpiled topsoil, reducing infiltration capacity and organic viability, while also driving rapid moisture stress and canopy decline in native vegetation as root zones come into contact with elevated salt concentrations. Both effects are the kind of surface moisture change that NDMI imagery is well suited to detect over time, which explains why the regulator was able to build a two-month timeline of continuous discharge without physical monitoring on the ground.

The tenement holder confirmed to DEMIRS that the discharge was unpermitted and had not been notified in advance. The stated reason was a lack of storage capacity in existing on-site retention facilities, indicating the operator chose to release excess groundwater directly onto surrounding land rather than seeking an emergency variation or interim discharge approval from the regulator. Under the Mining Act 1978 (WA) and the Mining Regulations 1981 (WA), a Stop Work Order compels immediate cessation of the relevant operational activities. Tenement conditions typically define an approved disturbance envelope and discharge parameters, and operating outside those bounds without authorisation constitutes a breach of tenement conditions that can expose the holder to further regulatory action, including potential prosecution or risk to tenure under state mining legislation.

The enforcement action does not appear to have involved a prior complaint, community report or scheduled compliance audit. The trigger was the department’s own use of spatial data analysis, which it cross-checked against tenement boundaries and approved disturbance limits before conducting a physical inspection to confirm the breach and issue the order. This sequencing, satellite detection followed by targeted physical verification, is the operational model practitioners should now expect from WA mining regulators.

What Remote Sensing Enforcement Means for Australian Environmental Compliance

While this is a Western Australian mining tenement matter under state-specific legislation rather than a Commonwealth contaminated land framework, it has direct relevance to how environmental due diligence and site assessment work is scoped nationally. Practitioners preparing Preliminary Site Investigations (PSI), Detailed Site Investigations (DSI) or ongoing Construction Environmental Management Plans (CEMP) for resource and infrastructure clients should treat satellite-based moisture and vegetation stress monitoring as a live enforcement tool, not a future possibility. This is consistent with the broader trend across Australian regulators, including EPAs in Queensland, New South Wales, Victoria and South Australia, toward incorporating remote sensing and spatial data into compliance monitoring for large-footprint sites where physical inspection frequency is limited by remoteness or resourcing constraints.

Although the NEPM 2013 assessment of site contamination framework and the PFAS NEMP address chemical concentration thresholds rather than discharge surveillance methods, the underlying principle in this WA case, that regulators can reconstruct an accurate breach timeline from spatial data alone, has direct bearing on how consultants scope groundwater and surface water monitoring programmes. A monitoring plan that only accounts for point-in-time sampling at bore or surface water locations may fail to capture what a regulator can now see continuously from above. Consultants should advise clients that any gap between approved discharge conditions and actual site practice is likely to be visible in the satellite record, and that contingency planning for retention capacity shortfalls, including early engagement with the regulator over emergency variations, is now a core element of defensible environmental management on large-footprint sites.

References and related sources

• Primary source: www.wa.gov.au

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This is an iEnvi Machete news summary. Prepared by iEnvi to summarise the source article for contaminated land, groundwater, remediation, approvals and site risk professionals.

Published: 03 Aug 2026

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