Wednesday 10 June 2026
A single unlined sump on a drill pad in a catchment area can trigger a stop-work order that grounds an entire exploration program. Remediation costs for groundwater contamination from drilling operations routinely exceed $200,000 before the regulator lifts the suspension. These are project costs that should never exist, and they are almost always preventable through basic field discipline.
Water management during mineral exploration drilling is regulated at the state and territory level across Australia, with codes of environmental compliance in Queensland, drilling guidelines in New South Wales, codes of practice in Victoria, and water-in-mining guidelines in Western Australia all setting explicit requirements for containment, decommissioning, and discharge prevention. Federal oversight applies through the EPBC Act where drilling activities may affect Matters of National Environmental Significance, including certain water resources.
The five habits below address the most common failure modes observed across Australian exploration programmes.
1. Locate drill pads and sumps outside drainage lines
A sump placed in or adjacent to a natural drainage channel becomes a discharge point in the first significant rainfall event. State codes across Queensland, Western Australia, New South Wales and Victoria explicitly prohibit the release of drilling fluids, cuttings, or contaminated water to waterways, wetlands, or groundwater systems.
The fix is mechanical: check topography before pegging drill sites, not after mobilisation. GPS-based site selection should account for overland flow paths, not just geological targets and access tracks. A drill pad positioned 30 metres upslope of a creek line is compliant by design. A drill pad in the creek line requires engineered controls that cost more and fail more often.
2. Line every sump
Unlined sumps are the single fastest path to a groundwater contamination finding on an exploration tenement. Polymer-based drilling fluids, fine rock cuttings, and trace hydrocarbons from rig lubricants all migrate through unlined soil into shallow aquifers. The migration is slow enough to avoid immediate detection and fast enough to be confirmed on the next compliance inspection.
Queensland's Code of Environmental Compliance (Condition 28) and New South Wales drilling guidelines both mandate impermeable liners in containment sumps. The cost of a heavy-duty HDPE liner for a standard exploration sump is negligible against the cost of a contamination investigation, which typically involves monitoring bore installation, laboratory analysis, and regulatory reporting over months or years.
3. Plug and decommission drill holes on schedule
Open drill holes connect aquifers that geological time separated for sound hydrological reasons. Cross-aquifer contamination from unplugged exploration holes can affect pastoral bores, environmental water sources, and future drilling programmes on the same tenement. The contamination pathway is permanent until the hole is properly grouted.
Most Australian jurisdictions require decommissioning of non-artesian exploration holes within two to six months of completion, except where holes are retained as monitoring wells under approved conditions. Leaving holes open because the rig has moved to the next drill line is how tenement conditions get breached and how future exploration applications on the same ground face additional scrutiny.
4. Draw down sumps before rain
Draw down sump levels before the onset of rain. Log volume of water used, fluid levels in sumps, any groundwater inflows encountered, any spills contained, weather conditions. This daily record serves two purposes: it demonstrates compliance if a regulator inspects, and it catches problems early.
A sump level rising faster than the drilling programme's water input signals a groundwater inflow that needs managing before it becomes an uncontrolled discharge event. The log is the early warning system. Without it, the first sign of trouble is often the discharge itself, by which point the compliance breach has already occurred. Field data entry discipline applies here the same way it applies to geological logging: the record is only useful if it is maintained consistently from the first hole.
5. Carry a spill response kit to every drill site
Fuel, hydraulic fluid, and lubricant spills happen at the rig, not at camp. A spill kit sitting 40 minutes away by track at the main laydown area is not a spill kit in any practical sense. State environmental codes require immediate containment of hydrocarbon releases on exploration sites. Immediate means the absorbent materials, containment booms, and disposal bags are on the pad when the hydraulic hose ruptures.
The kit contents should match the fluids on site: hydrocarbon-specific absorbent for diesel and hydraulic oil, general-purpose absorbent for drilling fluid overflows, and clearly labelled disposal containers. Kit inspections should be part of the daily pre-start, not a monthly audit item.
The bottom line
The drill programme that manages water well does not get shut down. That is the competitive advantage nobody talks about, because it is invisible when done right and catastrophically visible when done wrong.
At Norwest Exploration and Mining Services, we deploy experienced geologists and field technicians who understand that environmental compliance is a field discipline, not an office exercise. Whether you need one person or a full field crew, we place the right people fast.