Stabilization work on a sinkhole that appeared a few miles south of Grass Valley along Highway 49, jeopardizing the road’s stability, is nearing completion, according to transportation officials.
“Were hoping, given weather and everything else, to have everything done by the end of January,” said Gilbert Mohtes-Chan, a spokesman for California’s Department of Transportation.
Work on the sinkhole is 70 percent to 75 percent complete, said Rochelle Jenkins, a Caltrans spokesperson.
The sinkhole formed a mile north of Caltrans’ massive transformation of the La Barr Meadows intersection sometime before Dec. 5, when a foot of rain drenched Nevada County and the Sierra over a four-day period, causing widespread flooding. Rushing water found its way into a crack in a culvert alongside the road, causing the culvert to fail and create a deep sinkhole, according to Caltrans.
The hole was approximately 10-by-10 feet wide; however, its depth was undetermined, Jenkins said.
“We did not discover a mineshaft,” Jenkins said. “It wasn’t a mineshaft.”
Caltrans workers belayed into the void about 30 feet but did not see its bottom, even with aid of lights, Jenkins said.
“It was very deep,” Jenkins said. “It was a big hole.”
After replacing the culvert, Caltrans workers are in the process of backfilling and compacting the hole, Mohtes-Chan said.
“We have got it completely full,” Jenkins said.
Mohtes-Chan estimated that work on the project since its inceptions has roughly reached $300,000.
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