Wednesday, December 23, 2009

Kingston Coal-Ash Spill, One Year Later

Exactly one year ago, at 1am in the morning on December 22, an embankment gave way at the Kingston Fossil Plant, a coal-fired power plant operated by the Tennessee Valley Authority (TVA) near Harriman, Tennessee. Over one billion gallons of sludge spilled out of the impoundment, flowing into adjacent ponds, the Emory River, and residential areas. This sludge - officially branded "coal combustion waste" - is a toxic slurry of the ash and dust that remain after coal is burned in a power plant, mixed with water to make it manageable, and dumped into large holding ponds for indefinite storage.

October 2009 image map showing area impacted by December 2008 coal sludge spill

SkyTruth obtained aerial survey photography from the TVA showing the area as it looked before the spill; one week after the spill; three months later; and as it looks now. We analyzed the images to measure areas that appear to be directly impacted by the deposition of the sludge. Our analysis shows that up to 186 acres of surrounding land and water were directly impacted, and that 102 acres of formerly open ponds and waterways now appear to be permanently buried by sludge. There's even a 4-acre island of sludge persisting in the Emory River.

With these air photos we're not able to detect the areas throughout the Emory and Clinch Rivers that have likely been impacted as well. Erosion of these ash deposits, and transport through the river system, may continue for some time. The sludge "island" in the Emory River looks particularly vulnerable to being steadily washed downstream.

Meanwhile, the Environmental Protection Agency is still trying to figure out what to do about the management of coal combustion waste, a growing problem across America.

Wednesday, December 16, 2009

Timor Sea Drilling Spill - Now There's a Hurricane

Actually, it's called a cyclone in that part of the world. Now a small but surprisingly powerful Category 5 storm, Cyclone Laurence is moving through the Timor Sea parallel to the northwest coast of Australia, and is expected to make landfall near the town of Derby today.

NASA satellite image of Cat-5 tropical cyclone Laurence in the Timor Sea, December 15, 2009.

The oil fields in the Timor Sea have been evacuated, including the crew on the Montara platform where they're still working to install a permanent cement plug in the well that blew out on August 21 and spilled oil and gas for ten weeks. The well-defined eye of this storm, 19 miles in diameter, passed about 130 miles southeast of the platform on December 15. The storm was moving then at about 15 miles per hour toward the southwest.

Nasty weather really complicates operations at sea. Hopefully the temporary mud plug will hold until they can get back and finish this well-control job.

K86HAFPTY28W

Friday, December 4, 2009

Mount Tenabo - Cortez Hills Gold Mine Temporarily Halted

Yesterday a federal court of appeals temporarily blocked construction of a proposed 2,000-foot-deep open-pit gold mine on public lands in Nevada. Barrick Gold Corporation's Cortez Hills Mine is now on hold until the U.S. Bureau of Land Management revises its environmental impact analysis. The court ruled that BLM failed to adequately analyze the potential for the mine on Mount Tenabo to "pollute the air with mercury emissions and dry up scarce water resources."

Panoramic view of Mount Tenabo, Nevada, site of proposed open-pit gold mine.

The Cortez Hills mine has been vigorously opposed by the Western Shoshone tribe, which considers Mount Tenabo a sacred site. Much construction activity has already taken place for the proposed mine.

See more SkyTruth images of the site here.

Tuesday, December 1, 2009

Measuring the Direct Landscape Impact of Natural Gas Drilling

Gas-drilling activity on the Pinedale Anticline, October 2005.

Pinedale, Wyoming: the Pinedale Anticline natural-gas field is one of the largest tight-gas sandstone reservoirs in the Greater Green River Basin of southwest Wyoming. The U.S. Bureau of Land Management (BLM) controls 80% of the mineral rights in the 198,034-acre area. In 2008 the BLM proposed a new development plan that includes 10-acre spacing of wells, a potential 4,400 additional wells in the field.

Google Earth image showing gas-drilling impact on part of the Pinedale Anticline, August 2005.

SkyTruth measured the amount of landscape already directly impacted by natural-gas development in the Pinedale area. The analysis was done using SPOT XS satellite imagery acquired in September 2007, visually identifying the infrastructure -- well pads, service roads, yard facilities, and pipeline corridors -- associated with developing the field. The analysis was verified using aerial photos from 2005, and GIS data on all gas and oil wells downloaded from the Wyoming Oil and Gas Commission on June 26, 2008:


The total area directly impacted by natural-gas drilling as of September 2007 was 5,194 acres.

Gas-and-oil infrastructure in the Pinedale Anticline field at that time included:
  • 353 well pads covering 2,521 acres with a median size of 6 acres
  • 10 facilities covering 586 acres with a median size of 11 acres
  • 161 miles of service roads covering 1,559 acres
  • 17 miles of pipeline corridor covering 527 acres

Mountaintop Removal Mining, Part 2: Mountains at Risk

SkyTruth, in partnership with Appalachian Voices, documented the impact of mountaintop removal coal mining (MTR) over a 59-county area in Kentucky, West Virginia, Tennessee and Virginia by mapping the extent of mountaintop removal mining over a 30 year period using satellite imagery. The historical record shows a 250% increase in MTR occurring over the last two decades, from 77,000 acres in 1985 to over 272,000 acres in 2005. The size of the individual mines also ballooned, with some now covering 15 square miles. Over 2,700 mountain ridges were destroyed by mining. 

While this impacts an enormous area, how many more ridges and mountaintops are vulnerable to this destructive practice?
Map showing predicted risk of mountaintop removal coal mining for Wise County, Virginia
In order to create a risk map, the variables that correlate with MTR must be identified. Our Chief Scientist, Dr. David Campagna, performed a preliminary investigation to determine the drivers of mining occurrence in Wise County, Virginia. Variables such as coal thickness, overburden, land use type, roads, and hydrography were investigated along with our previous analysis of historical to recent mining activity. 

Results indicate that two geologic criteria – coal thickness and overburden best correlate with mining. Using these two variables, we generated a mining risk map for the county based on analysis of the main coal deposit in the area, the Pond Creek seam (see above). Knowing which ridges are at risk of being mined is the key to developing proactive strategies to limit further destruction, and predicting downstream impacts should mining occur.

Mountaintop Removal Mining, Part 1: Measuring the Extent of Mountaintop Removal in Appalachia

Aerial shot of mountaintop removal mining, Kayford Mountain, WV - Photo courtesy of Ohio Valley Environmental Council and Southwings

SkyTruth, in partnership with Appalachian Voices, documented the impact of mountaintop removal mining for coal over a 59-county area in Kentucky, West Virginia, Tennessee and Virginia. The goal of the project was to map the direct landscape impact -- the "footprint" -- of mountaintop removal mining (MTR) over a 30-year period, from 1976 to 2005.  The analysis was designed and conducted by our Chief Scientist, geologist and remote-sensing expert Dr. David Campagna.


Map showing total extent of surface mining from 1976 - 2005, color-coded by decade

With this analysis, and some great database and Google Earth work by Appalachian Voices, we can tell you exactly which mountains in Appalachia have been - or are are being -destroyed to power your home or business (thought you might like to know...). The methodology involved several steps. The first step included a land cover classification for each decade that identified all the mining occurrences at that point in time. This digital spectral classification process was accomplished using a Landsat satellite image database totaling eight gigabytes of data. Classification required a two-step process where the spectral signatures of land cover types were identified (vegetation, soil, barren or rock, water, etc) and then, through a decision tree analysis, mined areas are classed.

The next step was to classify these mine areas as “MTR” and “Other Surface Mining.” The definition of MTR, as put forth by the U.S. Office of Surface Mining, Reclamation and Enforcement, guided the development of a reproducible, rules-based method to classify the mines. Using digital elevation data from the U.S. Geological Survey 1:100,000 series, the terrain parameters of ridge top, slope, and valleys were calculated.  MTR mines were identified by calculating the amount of ridge top that comprised the mine’s total area.  Any continuous mined landscape that spanned over 320 acres and removed at least 40 acres of ridge top, or spanned between 40 - 320 acres and contained at least 10 - 40 acres of ridge top, was classified as MTR.  Mined areas that were smaller than 40 acres, or did not meet these conditions, were classified as "Other Surface Mines." 

This analysis shows a 250% increase in the MTR footprint occurring in the last two decades, from 77,000 acres in 1985 to over 272,000 acres in 2005. The size of mining operations also increased, with some contiguous mined areas reaching over 15 square miles. Over 2,700 ridges were impacted by mining. Summary statistics are shown below:
Mountaintop Removal Mines
Total MTR Area Since 1976 = 445,792 Acres
Largest Contiguous Mined Area = 10,410 Acres
Median Mined Area = 128 Acres
Average Mined Area = 406 Acres
Number of Mines > 1 mile2 = 73 
Number of Ridges Mined = 2,789
Total Acres of Impacted Ridges = 130,655 Acres
Average Ridge Length Mined = 1/2 Mile
Largest Ridge Removed = 504 Acres

Historical Analysis (Acres Directly Impacted by Mining)