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Strange hidden cave uncovered in Austin: Construction workers stumble across mystery near a high school

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interior cave near McNeil High School found during construction
A construction crew made a surprising discovery while excavating trenches near McNeil High School in North Austin. Photo courtesy of the City of Austin
entrance to McNeil High School cave in construction trench
The cave was the fifth and largest cave uncovered by constructions crews working on the Martin Hill Transmission Main Project for the City of Austin. Photo courtesy of the City of Austin
second interior shot of cave found near McNeil High School
After conducting a require environmental assessment, construction will resume. Photo courtesy of the City of Austin
interior cave near McNeil High School found during construction
entrance to McNeil High School cave in construction trench
second interior shot of cave found near McNeil High School

Construction crews working near a North Austin high school made a surprising geological discovery. 

On Aug. 5, workers came across a cave while excavating in front of McNeil High School for the Martin Hill Transmission Main Project. It is the fifth — and largest — cave found during this project.

Courtney Black, a spokesperson for the Austin Public Works Department, tells CultureMap that the cave is more than four feet deep and at least 20 feet long. After the discovery, crews consulted with the Austin Watershed Protection Department to assess whether further construction will negatively affect the local environment or any engendered species.

 Geological surveys are conducted before projects such as this, but as Black notes, there’s just no telling what you’ll find until you start digging. 

The project has been approved to continue with construction. "Work on the pipeline will continue while preserving the caves to the best of the crew's ability," Black says.

The caves were discovered while crews were laying 17,000 feet of concrete-covered steel pipe from the Martin Hill Reservoir on Howard Lane to an existing pipeline located near Parmer Lane and McNeil Drive. This will help transport water to the rapidly expanding northwest area of Austin. 

While the recent cave was a surprise due to its sheer size, Black says that the area is known for these geological wonders. "We talked with the principal and other administrators who said that they even found a few caves when the high school was being constructed," Black says .

Geological surveys are conducted before projects such as this, but as Black notes, there’s just no telling what you’ll find until you start digging. 

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