China is rich in rare earth elements and has dominated global rare earth mining and production since the 1990s. Its neighbor, Myanmar, is also a country rich in rare earth elements. In 2012, China’s Central Government implemented a strategy to shift away from mining and to focus instead on the processing of rare earth elements, which led primary extraction to increase in other parts of the world.

The prevailing assumption has been that while mineral extraction decreased in China following this declaration, and subsequently increased in Myanmar and other parts of the world. However, a new study by the University of Delaware shows that when it comes to the border regions of Myanmar and China, the dynamic is more complex.

Study area (Myanmar–China border)—Myitkyina (Kachin State) and Nujiang Prefecture (Yunnan Province) and Planet satellite data imagery (RGB = 642, Natural Color Composite). Chinkaka et al.

The open-access study, published in the journal Remote Sensing, used remote sensing techniques to look at changes in mining surface footprints between 2005 and 2020 in two rare earth mines located on either side of the Myanmar-China border, within Kachin State in northern Myanmar and Nujiang Prefecture in Yunnan Province in China.

Our empirical study used Google Earth Engine (GEE) to characterize changes in mining surface footprints between 2005 and 2020 in two rare earth mines located on either side of the Myanmar–China border, within Kachin State in northern Myanmar and Nujiang Prefecture in Yunnan Province in China.

Our results show that the extent of the mining activities increased by 130% on China’s side and 327% on Myanmar’s side during the study period. We extracted surface reflectance images from 2005 and 2010 from Landsat 5 TM and 2015 and 2020 images from Landsat 8 OLI. The Normalized Vegetation Index (NDVI) was applied to dense time-series imagery to enhance landcover categories. Random Forest was used to categorize landcover into mine and non-mine classes with an overall accuracy of 98% and a Kappa Coefficient of 0.98, revealing an increase in mining extent of 2.56 km², covering the spatial mining footprint from 1.22 km² to 3.78 km² in 2005 and 2020, respectively, within the study area. We found a continuous decrease in non-mine cover, including vegetation. Both mines are located in areas important to ethnic minority groups, agrarian livelihoods, biodiversity conservation, and regional watersheds.

The finding that mining surface areas increased on both sides of the border is significant because it shows that national-level generalizations do not align with local realities, particularly in socially and environmentally sensitive border regions.

The quantification of such changes over time can help researchers and policymakers to better understand the shifting geographies and geopolitics of rare earth mining, the environmental dynamics in mining areas, and the particularities of mineral extraction in border regions.

—Chinkaka et al.

Because detailed geological and mineralogical survey data is not freely available in China and Myanmar, the researchers had to take an extra step to confirm that the mines were actually being used for rare earth elements.

Surface mining extents for 2005, 2010, 2015, and 2020 draped on 2020 Landsat 8 OLI natural color imagery. The Myanmar mining sites are at the top of the images, the China sites at the bottom. Chinkaka et al.

To do this, they used satellite remote sensing and the USGS Spectroscopy Laboratory Library to determine the hyperspectral signature—basically a unique fingerprint left across the electromagnetic spectrum—by certain types of rare earth elements to verify their presence in these mines.

They indeed found amounts of neodymium in the mines, which is a rare earth element that is critical for permanent magnet production.

Resources

• Chinkaka, Emmanuel, Julie Michelle Klinger, Kyle Frankel Davis, and Federica Bianco. (2023.) "Unexpected Expansion of Rare-Earth Element Mining Activities in the Myanmar–China Border Region” Remote Sensing 15, no. 18: 4597. doi: 10.3390/rs15184597