Mining is a global industry, leaving behind thousands of abandoned mine voids across diverse regions, from South Africa and Canada to Chile and Australia. After closure and associated dewatering, these voids often fill with water, forming pit lakes that can pose serious risks to local ecosystems and communities due to potential contaminants like heavy metals, acidic water, or other pollutants. Monitoring water quality is essential for community safety, environmental protection, and meeting regulatory requirements.
Western Australia, for example, has approximately 2,000 mine voids, with more than half likely to become pit lakes. (1)
In this article we explore why sampling abandoned mine pits matters, the challenges of traditional methods, and how drone technology offers a safer, more efficient solution.
Why water sampling in Abandoned Mine Pits Matters
- Local Ecosystems
Water sources, natural or man-made, can attract wildlife and support plant growth. If the water is contaminated, it can harm these habitats. - Community Health
Some old pits sit near populated areas. If pollutants spread, they may affect drinking water or agricultural land. - Regulatory Compliance
Each country (and often each region) has its own framework for environmental oversight. In Western Australia, agencies like the Department of Mines, Industry Regulation and Safety (DMIRS) and the Environmental Protection Authority (EPA) require ongoing monitoring. Likewise, Canada’s provincial governments or Chile’s environmental agencies might mandate detailed reporting for closed mines.
Mine pit lake water quality can evolve for many years after mine closure, which makes managing these sites challenging and reinforces the need for regular water sampling. If pit lakes are appropriately managed, however, they can offer benefits such as water storage for mining operations, recreation, irrigation, aquaculture, livestock drinking water, or wildlife habitats.
Challenges with Traditional Sampling Methods
- Hazardous Locations
Physical access to pit water is often difficult due to site safety protocols. Many pits are in remote areas with steep, unstable walls, making approaches risky if using traditional methods. - Costly & Time-Consuming
Launching boats or using other traditional methods can be difficult and complex, requiring extensive planning, permits, specialised gear, and trained personnel, all of which drive up costs. - Inconsistent Data
Collecting water from various depths or multiple points can be complicated, especially in large or oddly shaped pits. Stratification, where distinct layers form, means water quality varies by depth, so multiple samples are required for accurate results.
Existing Sampling methods and their limitations
- Manual Grab Sampling
Straightforward for simple checks but risky for deep or difficult to reach areas - Automated Samplers
Require permanent installation at fixed points, which can be problematic if the terrain is unstable, remote, or changing over time. - Rope & Pulley Systems
Still rely on heavy manual handling in hazardous conditions, and exact depth measurements are prone to error.
How Drones Help Overcome These Challenges
- Easy Access to Hard-to-Reach Areas
Drones can fly over steep pit walls and quickly reach spots otherwise too dangerous for people to access. - Faster Sampling
Instead of setting up ropes or driving heavy equipment, a drone can hover, collect a water sample, and return in a fraction of the time. - Reduced Risk & Lower Costs
Fewer people onsite, less heavy equipment and quicker sampling reduce safety hazards and overall expenses. - Consistent & Accurate Data Collection
With the right equipment, drones can capture water samples from the same depth and location with GPS accuracy every time, improving data quality - Adaptability
Drones can operate under various climates and terrains, making them suitable for everything from arid deserts to coastal environments.
Practical Steps in Drone-Based Sampling
- Pre-Mission Planning
Teams use site maps and environmental data to define sampling points and flight paths that ensure representative samples. - Flight & Sample Collection
A drone equipped with water sampling device/s hovers at the chosen location/s and depth/s, collects the sample/s and returns it for lab-analysis. - On-the-Fly Adjustments
Real-time video and sensor data (sonar & altimeter) let operators tweak collection points if they see unusual conditions, such as discoloured water, debris or depth variation. - Data Management
Once tested, results are stored alongside flight logs, facilitating trend analysis, repeatability and easy reporting to regulators.
Challenges & Considerations for Drone Operations
- Regulatory Permissions
Appropriate licences and clearances are needed to fly drones, particularly near mining sites or in restricted airspace. Operations call for no flying above people. - Payload & Battery Life
Larger samples can reduce flight time due to weight so balancing the need for sample volume vs. the drone’s carrying capacity is key. - Operator Expertise
Teams need specialised drone certifications and knowledge of safe water sampling practices. - Weather & Climate
Extreme heat, storms, or high winds can affect flight stability and battery performance, so understanding local climate conditions is a major factor in planning.
Beyond Mine Pits
Though this article focuses on abandoned mine pits, drone water sampling isn’t limited to the mining sector. Here are just a few of the ways drones are revolutionising water monitoring in other industries:
- Environmental Monitoring of Lakes and Rivers
Ideal for tracking pollution, particularly after chemical spills or storms. - Industrial Effluent Testing
- Manufacturing and processing plants must regularly test water near discharge points. Drones make collection more efficient.
- Power Plants (coal-fired or nuclear) also benefit from drone sampling of cooling ponds or discharged water.
- Agriculture
Large irrigation reservoirs require regular checks of nutrient levels and pH, which drones can handle quickly and safely. - Disaster Response & Emergency Management
Rapid sampling of floodwaters following natural disasters helps assess contamination from sewage, chemicals, or other hazards. - Urban Water Infrastructure
Drone-based sampling in reservoirs or treatment plants cuts down on the need for boats or large crews. - Climate Change Monitoring
Scientists rely on frequent sampling of lakes and coastal waters to study temperature shifts, salinity changes and the spread of algae blooms.
Whether it’s a remote mine pit or an urban reservoir, the fundamental benefits of drone water sampling remain the same: safer operations, quicker data collection and more consistent results.
By embracing drone technology, industries and organisations worldwide can elevate water management and protection efforts – literally.
HOW REMSENSE DOES IT
At RemSense, we’ve been refining our water sampling process for quite some time. We’ve developed innovative solutions that make each mission safer and more efficient. Specialised operational methods and custom equipment allow us to collect multiple samples—up to 12 one-litre specimens in a single flight—at any required depth or separation from surface to floor.
By using a load-sensing tether point, an active payload safety release, and live sensor data via a smart mechanism, we minimise risks and consistently deliver reliable data.
To learn more about our approach, check out our water sampling case study or give us a call.
