Using drone mapping to detect unregulated gold mining

Illegal gold mining in protected natural reserves presents a complex environmental challenge. Beyond the immediate disruption to soil and riverbed integrity, these activities often introduce mercury into waterways and contribute to local deforestation, particularly in ecologically sensitive riparian zones. Monitoring such activity on the ground can be difficult due to accessibility and safety concerns.

This article outlines how drone mapping and photogrammetry were used to document indicators of illegal gold mining in a remote area. Through high-resolution maps and 3D models, the presence of hand-dug riverbeds, tree loss, and makeshift shelters near the river was recorded. According to a report from a source who prefers not to be named, forest guards were seen chasing away individuals involved in the illegal mining activity. This all provided visual evidence to support environmental assessments and response efforts.

Aerial surveys to identify activity

A long-standing international nonprofit has expanded its mission to include environmental monitoring using drone technology. Recently, the team began using aerial surveys and data analysis to help identify signs of illegal gold mining in protected forest areas.

Aerial drone image reveals evidence of deforestation and surface disruption near a riverbed—potential indicators of illegal mining activity in a protected area. High-resolution mapping enables detailed visual analysis to support environmental assessment and prevention efforts.

At the request of local forestry authorities, the nonprofit conducted drone mapping on-site and contributed to the analysis of the data. While drone and data training efforts have grown in the region, mapping large landscape corridors still requires access to advanced drone equipment, high-performance computing, and user-friendly photogrammetry software.

The mission

The mission itself was planned using Wingtra Hub, and it was flown using a Wingtra One with the RX1RII 42MP Camera. The data was then geotagged using WingtraHub and then processed in PIX4Dmatic.

Orthomosaic of the river corridor

Connection was lost during one flight due to the terrain, but they got about 80% of the mission, which was enough for the case. The planning of the whole project took significantly longer than the actual part involving the drone, as flying a drone in a National Park should be discussed in advance with the respective authorities. After that was settled, planning, flying, and post-processing the data was about 2-3 days of work.

Drones for good

While a drone map itself can not stop the gold mining, it can raise awareness and allow a systematic management approach, as well as periodic systematic comparisons of landscape change. The hope is that this data will be leveraged to continuously engage in preventing illegal activities.

A high-resolution drone image reveals signs of manual gold extraction near a river, including shallow pits, muddy water pools, and makeshift paths. This level of visual detail supports environmental monitoring and helps authorities assess the scale and spread of illegal mining activity

Going from the field to a high-resolution drone map—where every bucket of sand can be counted—in less than a day is remarkable, especially when compared to the challenges of accessing high-resolution satellite imagery. Not only is drone data faster to obtain, but it also offers the level of detail required to support meaningful analysis and informed action. In sensitive and fast-changing environments, that speed and clarity can make all the difference.

“Pix4D has developed great products that fit together seamlessly. With PIX4Dmatic, data processing is simple and efficient. For extended functionality, adding a PIX4Dsurvey license integrates perfectly into the workflow. Additionally, with PIX4Dcloud, our customers benefit from a user-friendly interface and effortless access to their data." - Manuel Allinger, CEO, Octacon Geotechnik GmbH