MANNFORD, Oklahoma - A section of Highway 51 between Sand Springs and Mannford is down to one lane while crews work to keep the road from crumbling a second time.

About a half mile stretch of the right lane of westbound Highway 51 is closed. The Oklahoma Department of Transportation says it has spent the past few months monitoring this stretch of the highway and found there is still deep movement underground.

ODOT says earth movement and wet weather caused the shoulder and right lane of the highway to crack, slide and eventually crumble back in 2015.

A little more than a year ago, crews completed a $1.4 million project, where they reworked the soil underneath the road, then repaved it. It wasn't too long after, that the pavement started to crack again in the same spot.

ODOT said, again, it is from natural earth movement. The department said it started a project this week for additional soil reinforcement work.

That reinforcement work is expected to be finished by mid-May.