Crafting mining extents from satellite images

In our study, we contribute to filling this knowledge gap by creating a new data set of mining extents derived by visual interpretation of satellite images. The new data set covers more than six thousand mining sites distributed across the entire globe. These mining sites have reported mineral extraction or activities between the years 2000 and 2017 according to SNL Metals and Mining data base [4]. The data set covers coal, all metal ores and some industrial minerals, but excludes mining sites of construction minerals, such as sand and gravel. Within the investigated regions, we delineated the mining areas (i.e., drew polygons) by visual interpretation of three satellite data sources: Google Satellite, Microsoft Bing Imagery and Sentinel-2. Figure 1 illustrates three examples of mines and related polygons that we drew based on the satellite data.

Figure 1: Examples of mapped mining polygons with Google Satellite images background. (a) Carajas iron ore mine in Brazil, (b) Batu Hijau copper-gold mine in Indonesia, and (c) Super Pit gold mine in Australia

The first example shows the main open cut of the Carajas iron ore mine complex in the Brazilian Amazon, which is among the world’s largest iron ore mining operations. The next example shows the Batu Hijau copper-gold mine. Despite its large open cut, this mine does not use much area for unused material, as the disposal of its tailings takes place in the ocean. The third example is the Super Pit gold mine in Australia, which is located in one of the largest gold producing regions in the world.

World-wide extent of mining areas

Figure 2 shows an overview of the geographical distribution of our mapped mining areas across the globe, resampled to 50 km grid cells to facilitate visualisation.

Figure 2: Global distribution of the mapped mining areas, aggregated to 50 km grid cells

Figure 3: Percentage of mining area mapped per country

From Figure 2 we can see concentrations of mining areas in many regions, for example, in northern Chile mainly due to copper extraction and northeastern Australia and East Kalimantan in Indonesia because of coal mining. We can also show that mining areas are highly concentrated in only a few countries. China, Australia, the United States, Russia, and Chile together account for 51% of the mapped mining area. Another ten countries account for 30%, and the remaining countries add up to 19% of the total mapped mining area (Figure 3).

Applications and improvements of the new data set

This novel data set can help improving environmental impact assessments of the global mining sector. For example, it can serve as the basis for studying mining-induced deforestation patterns. The data can also serve as a benchmark for further monitoring the temporal evolution of mining sites around the world and as training and validation data to support automated classification of mines using satellite images.

Although the first version of the data covers a large number of mining sites across the world, there are options for extensions. Work is currently ongoing to extend the data set to inactive mining locations such as closed sites and exploration stages, in order to deliver a complete account on the land used by the global extractive sector.

Citation

Maus, V., Giljum, S., Gutschlhofer, J., Luckeneder, S., Lieber, M. 2020. Worldwide mining activities use more than 57,000 km² of land. Results from a global assessment of mining land areas based on satellite data. FINEPRINT Brief No. 12. Vienna University of Economics and Business (WU). Austria.