A product used to seal the Highway 49 sinkhole is leaking into runoff water and will now require a clean up and more repairs. Caltrans Environmental Engineering Branch Chief, Doug Coleman says the sinkhole on Highway 49 just south of Grass Valley developed in early December when a heavy winter storm dumped a large amount of water into a culvert under the highway. The culvert which was built in the 1950s leaked, so they used a resin material called Styrene to coat the inside of the culvert as a repair. The Styrene was supposed to solidify but some of the liquid leaked out into the runoff water towards a creek. Coleman says it was detected by neighbors because of the strong plastic smell.
Motorists will now see a big red water tank at the site of the sink hole that Coleman says is in place to collect runoff water that might be contaminated with the Styrene until repairs can be made.
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The permanent fix will begin next week when Caltrans will pour a concrete slurry around the pipe to seal it . Coleman says it should take no more than two weeks to complete. It is not expected that lane closures will be needed during the repair.