Planet Imagery sheds light on Mine Expansions outside of Permit Boundaries

We were recently reviewing imagery of mine sites which experienced growth in 2017. We overlaid the mine permit boundaries that show where the government has legally granted companies permission to mine. We used our Landsat-based surface mining data to identify a set of candidate sites to examine more closely with higher-resolution Planet imagery through Planet’s Ambassadors Program. While looking at these sites, we noticed mining activity that seems to be occurring outside of permitted areas.

The Taywood West Mine as it appeared on a high-resolution Planetscope satellite image in July 2017. The mining permit boundary is shown in red; mining-disturbed land, based on SkyTruth’s analysis of lower-resolution Landsat 8 satellite imagery, is shown in orange and closely matches what we are able to see in this Planet image.  Apparent mining-related activity outside the permit area is highlighted in yellow.

The mine site continued to expand after July; the image below shows the extent of mining on October 19. More land outside the permit boundary appears to have been cleared since July 30.

The Taywood West Surface Mine is located in Mingo County, WV approximately 12 kilometers northeast of the town of Kermit and 76 kilometers southwest of the state capitol in Charleston.

The Taywood West Surface Mine (pictured above) caught our attention when we noticed evidence of mining activity, which fell outside the mine’s permit boundary. In the image, areas overlain in red show the extent of the mining permit; the bright areas of bare rock and soil on the image show where mining activity (cut and fill) activity has apparently occurred as of the date of the image (October 2017). Fifty-two acres of mining-disturbed land lie outside of the permitted area. According to permit data downloaded from the West Virginia Department of Environmental Protection (WVDEP), the permit for the Taywood West mine was issued to Southeastern Land, LLC in August 2005 and will expire in August 2020.

A 2004 study conducted in West Virginia showed a surprisingly high degree of mismatch between permit boundaries and actual mining, but we thought the situation had improved since then. Now we are not so sure, and we’re wondering how widespread this problem is. Accurate assessment of the location and amount of existing mine-damaged land is critical for forecasting the cumulative downstream impacts of mining in deciding whether to approve permit applications for new mining. And it’s critical for planning and executing the extensive reclamation work this region needs to recover from the negative impacts of coal mining. Whose job is it to make sure miners stay within the boundaries of their mining permit?

Monitoring Update: Oil Rocks In The Caspian Sea

The Oil Rocks (Neft Daşları)  is a massive offshore oil complex in the Caspian Sea. The complex was constructed in the late 1940’s by the Soviet Union and has been producing oil consistently since 1951. The area around the Oil Rocks has experienced catastrophe in the past, when a fire at a nearby platform was responsible for the death of 32 workers and a particularly nasty oil spill in December 2015.

As part of SkyTruth’s Watchdog program, we keep an eye on locations such as this. Over the past 2 months, we estimate that over 380,000 gallons of oil have leaked into the Caspian Sea, based on our assumption that the slicks we are observing are 1 micron (1/1000th of a millimeter) thick.

Above: The European Space Agency’s Sentinel 1 radar satellite captured this image on December 9th revealing a 306 square kilometer oil slick surrounding the Oil Rocks complex.

Above: Sentinel 1 collected this image of the Oil Rocks with a much smaller oil slick (23 square kilometers) on December 21, 2017.

Wind speeds in the Caspian Sea were as strong as 35 knots toward the south on December 21st and may have dispersed an additional volume of oil on the water’s surface.

Above: Sentinel 1 imagery from January 7, 2018 reveals the Oil Rocks leaking oil. The slicks cover a total area of 34 square kilometers.

Wind speeds were very low (between 0-15 knots) on January 7th heading southward, allowing the oil to form slicks around the complex.

And on January 13th, they were between 20-30 knots also heading southward. Similar to the image from December 21st, the high wind speeds may have contributed to dispersing the oil.

Above: The most recent Sentinel 1 image collected on January 19, 2018 reveals a massive oil slick emanating from the Oil Rocks complex, covering an area of 1094 square kilometers and containing at least 288,940 gallons of oil.

For context, 50,000 gallons of oil leaked from the SOCAR#10 platform during a fatal fire in 2015 mentioned above. And this massive Azerbaijani complex has a consistent leaky history on satellite imagery. Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan, the five countries surrounding the Caspian, all have efforts to tap into the Sea’s 44 billion barrel reserve. But this most recent satellite image from January 19th suggests a troubling future for the environment of the Caspian Sea.

What We Can See, In Heat Maps

Here at SkyTruth, we depend on our friends at the European Space Agency (ESA), NASA and the U.S. Geological Survey (USGS) for their support in providing access to data and images from their fleets of government-operated satellites.

The Sentinel missions are pairs of satellites that are part of the Copernicus program at ESA. Sentinel 1 is of particular use to us for offshore oil pollution monitoring as the radar sensor it carries can penetrate cloud cover and highlight oil slicks against water. The optical-infrared imaging system on Sentinel 2 covers a wide range of spectral bands that we can process to create a variety of true-color and false-color images, which we use to study environmental issues like drilling, mining, and deforestation.

Many folks assume these Earth-Observing satellites are continually collecting images as they orbit overhead, but for most systems that is not the case. Much of the time the sensors are turned off to save power, to conserve onboard storage, because of limited communications bandwidth, or because the operators just aren’t interested in covering large areas where there isn’t much demand for imagery (far out at sea, or over vast deserts, for example).  We thought it would be interesting and useful to analyze the archives of imagery collected by these systems, and map where they’ve taken images, to get a sense for how frequently they are covering various parts of the planet.   

The heat maps below show the locations of all the images collected by Sentinels 1 and 2 since they became active, and for a recent calendar year (2016). As you can see, the distribution of images is not at all uniform, with a strong bias toward covering Europe and the Arctic. Most of the ocean doesn’t get imaged at all. Please note that “scene count” means the image count at any particular point on the map.

The U.S. Geological Survey (USGS) manages the images produced by NASA-built satellites in the Landsat program which has been imaging the Earth since 1972, much longer than any other civilian satellite imaging program. Currently, only Landsat 7 and 8 are in operation (with Landsat 9 planned for 2020) and, similar to Sentinel 2; they provide us with instrumental data collected across a range of spectral wavelengths which we can process into color images.
Like the Sentinel satellites, the Landsat archives have sparse coverage in the ocean. While there is some pro-northern hemisphere bias, the operators of Landsat 8 have made a concerted effort to distribute the collection of imagery more evenly over all of the Earth’s land masses, with the exception of a few large areas that are chronically impaired by heavy haze, dust, smog, or cloud cover. Can you pick them out?  

Landsat 8 image from June 21, 2014 showing the oil slick from the Taylor Energy site.

Taylor Energy (Site 23051) Cumulative Spill Report – 2017 Update

With President Trump preparing to open the Atlantic coastline to offshore drilling, we thought it would be a good time to revisit the cautionary tale of Site 23051 — Taylor Energy’s 13-year old continuous oil leak in the Gulf of Mexico.

We’ve estimated the cumulative amount of oil that has leaked from the Taylor Energy site since 2004, finding:

  1. Crude oil has been leaking continuously from this site for more than 13 years; and
  2. The estimated cumulative volume of crude oil spilled into the Gulf of Mexico from this chronic leak over the period 2004 – 2017 now stands between 855,421 and 3,991,963 gallons.


The Taylor Energy site perfectly captures the dysfunction of offshore oil development: In 2004, an underwater mudslide caused by Hurricane Ivan toppled one of the company’s platforms and buried the damaged wells attached to it on the seafloor.  Reports of oil on the surface at the site of the wreckage followed shortly after and a secretive clean-up effort ensued.  

In 2008, after several failed attempts to stop the leaks and Taylor Energy’s decision to sell off all of its income-generating oil and gas assets in the Gulf, federal regulators ordered the company to post a $666.3 million security bond to ensure there was enough money to plug the wells and clean up remaining pollution.  

In  2010 and 2011, Taylor Energy used a leased drill rig called the Ocean Saratoga to slowly find and plug some of the damaged wells (only 9 of the 25 wells at the site have been plugged).  Additionally, three underwater containment domes and an underwater collection and containment system were put in place at the wellhead area to try and capture any remaining oil.

Taylor Energy’s next step was to sue the government to try and recover more than $400 million from the trust they had set up previously.  The lawsuit is in limbo amid negotiations over the company’s remaining responsibility and the feasibility of further clean-up. Documents filed by the Justice Department on December 15th revealed new evidence of two plumes of oil and gas resulting in an “ongoing oil release,” bringing some renewed hope Taylor Energy will be held accountable for its mess.


SkyTruth became aware of the chronic leak from the Taylor Energy site in 2010 while analyzing satellite imagery of the BP / Deepwater Horizon disaster.  We’ve reported on slicks coming from the Taylor Energy site dozens of times in the years since, and in 2012 we released a cumulative spill report estimating that between 300,000 and 1.4 million gallons of oil had leaked from the site since 2004.  But with offshore drilling in the Atlantic looming once again, we thought now would be a good time to revisit those calculations and reconsider the risks that offshore drilling poses for coastal communities.

Our initial report estimated the cumulative amount of oil that had leaked from the Taylor Energy site over the period 2004-2011. We’ve updated those calculations to include years 2012-2017, finding that:

  1. Crude oil has been leaking continuously from this site for more than 13 years; and
  2. The estimated cumulative volume of crude oil spilled into the Gulf of Mexico from this chronic leak over the period 2004 – 2017 now stands between 855,421 and 3,991,963 gallons.

Our 2017 update uses the same methods outlined in our 2012 cumulative spill report. Our update analyzes the information contained in 2,719 public pollution reports filed with the National Response Center. Most reports were likely filed by Taylor Energy or their contractors covering 2,275 out of 4,852 days (just 47%) from the first report of oil at the site on September 17, 2004, through December 12, 2017.  We computed an ‘estimated average daily slick extent,’ and from that, we derived an ‘estimated average daily flow rate’ for each calendar year since the spill began.  Multiply the daily flow rate by the number of days the site has been leaking, and you have a rough estimate of the cumulative volume of the spill. For more on the methods, see our original report.  The data and analysis are accessible here.

In addition to our reliance on the accuracy of the pollution reports submitted by Taylor Energy, there are two assumptions we used to compute the average daily flow rate:

  • the average oil thickness in observable slicks; and
  • the average rate of degradation of an oil slick expressed as a half-life.

For average thickness, we used our conservative standard of 1 micron (1 millionth of a meter); we also computed everything using an even more conservative estimate of 0.5 microns to reflect the possibility that this slick is thinner than most.  For degradation half-life, we assumed that one half of a given amount of a thin slick of oil on the surface of the ocean would degrade in 3-7 days. We believe this range is a very conservative assumption because the longer the assumed lifetime of oil on the surface of the water, the lower the implied daily flow rate will be.

Combining all our data on slick extent with the high and low values for each of the key assumptions, we get four values for estimated cumulative oil spilled:

Half-life (Days) Thickness (Microns) Estimate (Gallons)
3 1.0 3,991,963
3 0.5 1,995,981
7 1.0 1,710,841
7 0.5 855,421

There is another potentially troubling trend in the data: since 2015, the average daily reported sheen extent has been significantly larger than in the past, while the number of pollution reports submitted to the NRC has come down.  

Average Daily Reported Sheen Extent
Year # of reports # of days with reports Average daily reported sheen extent (sq. miles)
2017 192 161 12.845
2016 176 147 14.351
2015 371 328 15.33
2014 346 314 4.423
2013 361 302 1.572
2012 323 309 0.337
2011 130 128 1.1
2010 167 164 1.7
2009 381 260 5.83
2008 272 162 2.73

On the one hand, these numbers could be the result of more diligent and accurate measurements made during routine monitoring and overflights, spurred in part by the public scrutiny this chronic leak has come under due to the work of SkyTruth and our partners in the Gulf Monitoring Consortium.  On the other hand, they could be the result of some qualitative change on the seafloor, in the damaged wells, or in the subsea reservoir that is allowing larger amounts of oil to leak out into the Gulf.


The slight decrease in average reported sheen size over the past three years is somewhat encouraging: if the significant jump in 2015 was indeed due to more accurate reporting by Taylor Energy, then this recent downward trend could indicate the leaks are finally slowing.  But we are hampered by our dependence on observations and reports submitted by the responsible party, Taylor Energy.  These reports have been proven inaccurate, systematically underestimating the size of the slick by more than an order of magnitude compared with independent measurements based on direct observation of the slick on satellite imagery.  Direct, regular measurement and observation of the leak by a neutral party is crucial to understanding what is happening and predicting the likely future at this site. For this reason, we will continue our monitoring work.




The remnants of a likely bilge dump (dark streak) possibly from a vessel traveling north to a tanker “parking lot” (the cluster of dozens of bright spots, each representing a vessel at anchor) off the coast of United Arab Emirates.

From Monitoring for Bilge-Dumping to Analyzing Coal Mining Activity and Mapping a Proposed Pipeline Expansion, My Year in Review

International Projects

This summer, SkyTruth began monitoring bilge dumping “hotspots.” I focused my monitoring efforts in the coastal waters surrounding the United Arab Emirates and Oman or the “tip” of the Arabian Peninsula. I began by visiting the European Space Agency’s datahub (and USGS) daily and downloading tons of imagery. The downloading of imagery was tedious and time-consuming. Using Google Earth Engine, we created scripts to input an AOI and automatically queue up all the imagery in a specified date range, which is easy. But Earth Engine has a lag time ingesting new imagery from various satellites, so I still need to manually download from ESA’s data hub to obtain the most recent imagery. I customized different versions of the script with different AOIs covering the coastal waters I wanted to monitor.

The remnants of a likely bilge dump (dark streak) possibly from a vessel traveling north to a tanker “parking lot” (the cluster of dozens of bright spots, each representing a vessel at anchor) off the coast of United Arab Emirates.

The remnants of a likely bilge dump (dark streak) possibly from a vessel traveling north to a tanker “parking lot” (the cluster of dozens of bright spots, each representing a vessel at anchor) off the coast of United Arab Emirates.

Bilge is an oily liquid that accumulates in the bottom of the hull, and vessel operators will sometimes just dump it overboard. If the vessel is moving while bilge dumping, then the slick appears on radar satellite imagery as a long, skinny, black line. But if a vessel releases the fluid while anchored then the slick can appear as an irregular black patch. There are examples of both above and below. Sometimes the vessel would still be in the range of its environmental “gift.” Then we could report on that vessel as the likely culprit evidenced by satellite imagery. Satellites don’t lie.

The Nordic Jupiter, a crude oil tanker, anchored offshore Fujairah in the United Arab Emirates, and located at the likely source of an apparent oil slick, suggesting a leak or possibly intentional bilge dumping.

The Nordic Jupiter, a crude oil tanker, anchored offshore Fujairah in the United Arab Emirates, and located at the likely source of an apparent oil slick, suggesting a leak or possibly intentional bilge dumping.

Domestic Projects

Much of my time was spent on the Google Earth Engine surface mining identification process, which involved using Landsat satellite imagery to create a composite of only the greenest pixels from each year’s summer months and creating a NDVI band from that composite. The purpose was to identify bare rock and soil typical of active strip-mining operations, like mountaintop removal mining (MTR) to extract coal.

The Normalized Difference Vegetation Index (NDVI) is a ratio of a pixel’s red value to its near-infrared value. Vegetation absorbs most visible light but reflects the infrared, while bare surfaces reflect both. A low NDVI value indicates a bare surface and a high NDVI value indicates healthy vegetation. By masking out all urban areas, streets, railroads, etc., the only large bare surfaces left in our Appalachia study area are large-scale coal mining operations.

This process requires a lot of satellite imagery. To accomplish this, I used Google Earth Engine, a cloud-based platform with access to satellite imagery collections and various geospatial datasets, including the entire archive of Landsat images going back into the early 1970s.

In central Appalachian states like West Virginia, mountaintop removal is the process of removing the several top layers of rock to expose coal seams. It is a resource-intensive process that results in massive landscape change.  As much as 85% of federal coal comes from Wyoming and Montana, specifically the Powder River Basin. My job was to attempt to adapt our process designed around Appalachia to the flat, dry shrublands of Wyoming and document the results.

The first step was creating a new area of interest (AOI). In Wyoming, the Powder River Basin spans two counties in Wyoming (Converse and Campbell), and those county boundaries formed the study area. The next step was creating the mask to eliminate areas that we didn’t want to analyze. That process involved downloading GIS shapefiles for hydrology (lakes/ponds, rivers/streams), urbanized areas, roads, railways, and oil & gas drilling sites. Shapefiles are georeferenced to represent these features on a map accurately. To create the mask, these shapefiles were merged and converted to a binary image. We could exclude these elements from the analysis because some were misidentified as active mining.

Coal mining in Black Thunder coal mine, WY from 1985 (in green) to 2015 (in red) overlain on 2015 aerial survey photography (NAIP).

Annual progress of landscape disruption caused by coal mining at the Black Thunder coal mine, WY, from 1985 (green) to 2015  red) overlain on 2015 aerial survey photography (NAIP).

I also worked with Tracy Cannon of Eastern Panhandle Protectors on Mountaineer Gas Company’s proposed pipeline across the Eastern Panhandle of West Virginia. A very rough, general path for the pipeline had been published, but the particular route is not being shared by the company or state regulators. To give the public a more precise view of the pipeline’s likely route, Tracy visited county courthouses and gathered publicly available information about easements purchased by the gas company on dozens of properties in the area. She shared that information with us. We combined it with a public GIS layer for tax parcels that includes the outlines of residential and commercial properties. By using Google Earth to view all of the properties that had sold easements to the gas company, a more detailed pipeline path began to take shape through Morgan, Berkeley, and Jefferson counties. I discussed some assumptions about pipeline construction with the Protectors (to minimize construction costs a pipeline will take the shortest route between two points, but will also avoid sharp turns and steep slopes, excessive road and stream crossings, and when possible will keep clear of homes and other structures. With that in mind, I analyzed the Google Earth imagery and manually traced what I considered to be the likely pipeline path through our own Eastern Panhandle. The map shown below is our “best guess” based on the easement information provided by Tracy, and the very crude maps made public by Mountaineer.

The hypothetical Mountaineer pipeline path (dashed red line) overlain in Google street-view. The proposed pipeline enters Morgan County at upper left across the Potomac River and continues through Berkeley and Jefferson County.

The hypothetical Mountaineer pipeline path (dashed red line) overlain in Google street-view. The proposed pipeline enters Morgan County at upper left across the Potomac River and continues through Berkeley and Jefferson County.

My time as a SkyTruth intern was divided among a diverse set of projects, and it was certainly well spent. I’ve garnered an in-depth understanding of GIS and satellite imagery processing, map-editing, and worked in a team environment to accomplish complex tasks. Satellite images offer so much more than their beauty. I conclude my time at SkyTruth a true believer in the power of satellite imagery for environmental conservation. If you can see it, you can change it!