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Into The Void: Mapping Abandoned Mines In 3D

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`Georeferencing’
At his office in Ashley next to an abandoned coal breaker, Hughes explained how he and his colleague, Michael Hewitt, turn 2-D paper maps into 3-D digital maps. The process is known as “georeferencing,” and, for them, it involves a lot of mouse-cursor tracing over the lines on scanned images of old mining company and government maps.

On his computer, Hughes pulled up a preliminary map he and Hewitt made by combining mining company maps with data from a series of reports from the U.S. Bureau of Mines in the early 1950s. The map shows the horizontal extent of the pool that formed when the abandoned mines flooded, along with arrows that show the direction of the water’s flow.

EPCAMR also measured the water depth in several of the approximately 40 bore holes all over the Wyoming and Lackawanna valleys. The measurements help Hughes and Hewitt draw boundaries for the underground lakes.

“We would measure the water elevation inside of that bore hole to get at what the elevation of the pool is,” Hughes said. “That elevation of the water, we extend it out underneath the ground to the contour of the underground mine workings.”

The map they created using these methods is still two-dimensional. To add the vertical axis, Hughes is using cross-section maps of the Lackawanna and Wyoming valleys, which he lines up on a virtual plane. The series of cross-sections looks like a set of sheets hung up on a virtual clothesline. Hughes said this process is known as “curtaining.”

He uses a mouse to trace the lines on the cross-sections representing rock, coal and void space. Combining this with the horizontal map yields a digital, 3-D representation of the Lackawanna and Wyoming valleys.

When completed, the maps could help property owners decide whether to carry the department’s mine subsidence insurance, Witman said. She said the average cost to repair a home with mine subsidence damage is $50,000.

Ninety-five percent of people living in mine-affected areas do not carry subsidence insurance, Ruane said.

But most residents do know about it, according to the board’s surveys.

“The vast majority of people in the mining region know about mine subsidence and know about mine subsidence insurance,” he said. Most are simply willing to take a risk.

Keith Tucker, executive director of Lackawanna Neighbors Inc., said his organization carries mine subsidence insurance on the properties it manages.

He said one subsidence in the 1990s did $200,000 of property damage to a 10-acre site. In summer 2012, a sewer line disappeared underneath Midtown Apartments on Adams Avenue. Tucker said when a construction crew cut into the kitchen floor in the apartment complex, they found a void underneath.

The most recent incident was a few months ago at Vine Street and Adams Avenue. Tucker said the corner of a building was cracking, so he called DEP. Within a day, the department arrived to prop it up, he said.

“If I had a home, I’d like to see it and look at what’s under my house,” he said.

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Posted by FanningCommunications on Nov 1st, 2013 and filed under News. You can follow any responses to this entry through the RSS 2.0. You can leave a response by filling following comment form or trackback to this entry from your site

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