SkyTruth is making large strides in understanding the ecological history of mountaintop mining. In the year to come, we plan to dive even deeper.
Those of you who’ve been following our work will recognize winter as the time of year that we often release updates to our Mountaintop Mining dataset, or give updates about the new directions that we’ve taken this work. We have continued to expand our mining program area to better understand the complex legacy coal plays in Appalachia, and are setting up for a year of even more robust analysis to come. As long as mining mars the rivers and forests of Appalachia, we will continue to monitor it and work to create data that allows communities, regulators, and researchers to hold mine operators accountable for their recovery obligations.
As part of our annual update to our dataset, we found that in 2022 75 km2 of new land was impacted by surface mining. We’ve also made some slight changes to the MTM data that we provide, by publishing data through the most recent full year. Our methodology, described in our 2018 paper, employs a data cleaning step that uses data from preceding and subsequent years to remove errors in detection: if a pixel is classified as a mine in 1985, non-mine in 1986, and mine in 1987 the data for 1986 is corrected to classify it as a mine. The opposite is also true for pixels classified as non-mine > mine > non-mine. We are now providing the un-cleaned data from the most recent year, 2023, as provisional detections. While any new land clearing due to mining is dramatic, the relatively small area cleared in 2022 highlights the continued decline in coal production across the region. As this decline continues we are shifting the focus of our work to explore the long-term geographical and ecological impacts of MTM operations across Central Appalachia. As we shift our focus, we are still committed to providing regular updates to our mine footprint dataset. To accomplish this without taking unnecessary staff time to run and process these updates, we worked to create an automated processing pipeline that drastically reduces the amount of time needed to prep our updates.
In 2023 we also made significant strides in understanding the full impacts of surface mining through the integration of early Landsat data into our detection methodology. By incorporating imagery from the Multispectral Scanner (MSS) sensors carried on the first three Landsat satellites, we are now able to detect mining as early as 1973. Our methodology for detecting mining from MSS imagery mirrors our existing approach to mine detection in the region. However, working with data from the old MSS sensors onboard Landsat satellites 1, 2 and 3 presents unique challenges when compared to working with the more advanced Thematic Mapper (TM), Enhanced Thematic Mapper (ETM), and Operational Land Imager (OLI) sensors carried by the later Landsat satellites (4-9). Landsat MSS data is provided at 60m resolution, as opposed to 30m for TM/ETM/OLI sensors. These early satellites also have smaller data archives, so there is less imagery per year than there is in later years. These factors contribute to a lower overall accuracy for our detections from 1973-1984 than from our 1985-2023 detections, so we are releasing the new data from 1973-1984 in a provisional (“beta”) state. We have plans to improve the data in the future making use of improved access to mining permit data, as well as newly available historic elevation data for the region. As we provide this data in its beta format, we welcome any input users may have about ways to improve our detections or regions where this new data performs poorly.
In 2023 we also began exploring the topographic impacts of MTM. Through the use of an assortment of publicly available elevation datasets, we are now working to analyze the volumetric effects that mountaintop removal mining and valley fills have on the Appalachian landscape. Working with elevation data provides its own set of challenges to overcome in order to conduct helpful analyses. These data lack the temporal resolution of imagery: while the Landsat satellites provide us with a comprehensive set of images showing us what Earth looked like going back to the early 1970’s, elevation datasets often have decade-long gaps between them. As an example, the Shuttle Radar Topography Mission (SRTM) is a global elevation dataset that was collected in 2000; the next global elevation dataset is the ASTER Global Digital Elevation Model which was collected in 2009. In addition to understanding what mined landscapes look like today, it is also important to have a baseline dataset that shows what the region looked like before mining operations began. We recently acquired a historic elevation dataset, courtesy of the USGS, that provides information about what the Central Appalachian landscape looked like in the 1960s and 1970s. By comparing historic and contemporary data, we will gain a better understanding of the nuances of mining operations: by identifying areas that experience loss of elevation we can better detect the areas cleared for mining; by identifying areas which experience elevation gain, we can highlight valley fills. Having a clearer understanding of where each aspect of MTM takes place will facilitate better research into the different environmental impacts resulting from each practice.
In the year to come, we plan to continue developing our datasets and analyses to provide researchers and environmental advocates with actionable information about the state of mined lands in Appalachia. Building on our expertise we plan to automate our landscape recovery assessment ensuring that the health of mined lands is regularly monitored and that the information is readily available. We plan to make use of both historic satellite imagery and elevation data to improve our mine detection algorithm, increasing our overall accuracy, and allowing us to determine what pre-mining landscapes looked like. This assessment of historic landscapes will provide essential information that can be used to compare pre- and post-mining ecosystem health.
Each year that passes we gain a better understanding of how mining has impacted Appalachian ecosystems and communities. As we work to improve the uses of our data, we want to ensure that it remains helpful to researchers, environmental advocates, and communities impacted by mining. If you have insights about improvements we can make, ideas for new work that would be useful, or are interested in helping us illuminate these impacts we invite you to reach out and get involved!