Looks like some form of leaching process going on here.
Leaching process
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© Bing Maps
By kjfitz @ 2005-08-20 22:47:22
cthippo
@ 2010-09-18 04:36:16
According to Google Maps that is the Nugent Sand Company, so most likely they are pumping sand slurry out of the lake and letting the water run off the pad.