LOUISVILLE, Ky. (WDRB) -- The Louisville Zoo and Louisville Mega Cavern reopened Friday, after being closed for nine days as engineers surveyed the sinkhole that opened on the property earlier this month.

The sinkhole, which was about 60 yards wide and 90 yards long, is in the southern part of the zoo that doesn't hold any animals and is closed to any pedestrian traffic.

The zoo said in a news release Thursday that the remainder of the property doesn't appear to be affected by the sinkhole. Below is a report from engineers on the status of the sinkhole:

Jennifer Latham, who teaches Earth Sciences at Indiana University Southeast, said there could have been several causes. Sinkholes are often from too much water or a disruption in the earth.

Latham said all the rain over the last month could have contributed.

"You can take sinkholes, and you can fill them back in, but it's already shown this is an area that is unstable within the rock structure," Latham said. 

The Louisville Mega Cavern said it's reopening after two engineering firms assessed the area. Both of those reports can be found below:

The Zoo's team hasn't released what it believes to be the cause of the hole, but the Mega Cavern's team says it's clear water was a major factor.

The report shows excessive runoff got into the soil and limestone over many, many years. The report also says the small earthquake that took place in Tennessee last week was not a factor.

Both Mega Cavern and Zoo officials are stressing that this was an isolated incident and they're now safe to reopen.

A barrier is being built 40 feet from the sinkhole to protect people from the area. Guards will watch the area until it is completed this week. That wall will remain in place until a permanent solution is configured.

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