A KC area highway closed for a ‘mine collapse.’ Or was it a sinkhole? Here’s what we know

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Missouri Department of Transportation officials briefly closed Missouri 291 in Independence last month due to what was first called a mine collapse by city officials, but reopened it days later.

Now, they say there was never a collapse of the mine there. Instead, they say it’s a sinkhole nearby.

Weeks later, officials from MoDOT and the city of Independence still have not answered questions about exactly where the sinkhole happened, the severity of the problem, whether the mine under the roadway was impacted or whether there’s any potential impact to the roadway itself. Officials have also not clarified what sort of mine is under the road, or how often — or even if — that mine is inspected.

It’s also not known exactly how MoDOT determined, within days, that the highway was safe to reopen.

MoDOT first announced on June 27 that it had closed roughly a mile of Missouri 291 in Independence, from Truman Road north to U.S. 24. The Star doesn’t have specific mile markers of exactly where the closure was located.

According to MoDOT ’s initial news release, the roadway was closed as a precaution due to a a new crack that developed in the mine under Missouri 291. MoDOT crews closed the highway at 5 p.m. for safety, and said it would be closed until further notice.

Immediately after the closure, MoDOT was unavailable to comment about the closure to The Star.

The City of Independence instead confirmed that, “MoDOT crews discovered a crack in the roadway while inspecting a recent mine collapse in the area. Out of an abundance of caution, the road is closed under further notice.”

The city said their information about the road closure being caused by a mine collapse came directly from MoDOT. However, they also mentioned the crack could potentially be a result of a cave collapse.

But just two days later, on June 29, MoDOT reopened the road.

According to MoDOT’s statement at that time, “experts completed their evaluation and inspection in the mine and determined the roadway could be reopened to traffic. MoDOT will continue to regularly monitor the mine for any changes.”

Since MoDOT remained unavailable for comment, The Star contacted Missouri Department of Natural Resources.

On July 1, Andrew at the Geological Survey Division of the Missouri Department of Natural Resources responded to The Star via email, saying, “Our information is the collapse in Independence is due to a mined out quarry area and not a cave.”

After repeated requests to MoDOT for information, the explanation for the closure changed. One week later, Melissa Black, communications manager at MoDOT, said via email that there was no issue with a mine.

When asked for further details, Black said, “There was a sinkhole on private property adjacent to the roadway, but we did not have a mine collapse under a state road.”

Black said she couldn’t speak to any information about the sinkhole since it happened on property that MoDOT doesn’t own, telling The Star that questions about the sinkhole would have to be directed to the property owner. The Star wasn’t provided specific information indicating who the property owner is, or where the property is located.

When asked about the city of Independence’s published statement, Black said, “ I can’t speak directly about information from the city of Independence. I would just reiterate we are continuing to monitor 291 Highway, we had experts review the mine under MO 291 and found it to be safe with no concerns.”

MoDOT did not clarify why their story about the reason for the closure had changed, or whether there were any ongoing safety concerns about the sinkhole.

Sinkhole vs. mine collapse

According to the U.S. Geological Survey , sinkholes are land depressions that result in the ground collapsing and forming a hole.

Rainwater is the main cause of sinkholes, with water entering the depression during rainfall and draining into the subsurface. This water seeps into cracks, eroding rocks and eventually leading to the creation of underground caves and other openings, according to National Geographic .

Sinkholes in the United States are most commonly reported in Missouri, Florida, Texas, Alabama, Kentucky, Tennessee, and Pennsylvania, according to the U.S. Geological Survey .

Mine collapses occur when the structural components that uphold the mine, such as pillars, walls, or ceilings, begin to cave in.

Constructing above an abandoned mine can be risky, according to North Carolina Environmental Quality , as it may weaken the mine or the ground surface nearby. This type of collapse can also cause sinkholes to begin.

Missouri 291 — a route that has a steady flow of traffic on a typical day, including semi-trucks transporting goods and making deliveries — runs through both industrial and residential areas. Many underground industrial parks and commercial warehouses are located between Truman Road and U.S. 24, where this incident reportedly took place.

‘It’s not an issue until it is an issue’

The Star reached out numerous times to MoDOT, Mine and Cave Safety — Missouri Department of Labor , and the Missouri Department of Natural Resources, but haven’t received clear answers on what type of mine is under the highway, what’s causing the crack or sinkhole to form nearby, how problematic it is, and what’s being done to ensure it doesn’t turn into a bigger problem.

It is still uncertain whether there was a crack in the road, whether there was a mine collapse that MoDOT was investigating before discovering the sinkhole, and where exactly the sinkhole was located. Additionally, it is unclear whether the sinkhole next to the road caused the crack that formed in the mine beneath the road, as mentioned in several news releases.

It’s also unclear how often the mine there is inspected, or whether the mine might be the reason for the sinkhole.

David Attebery, program manager of Mine and Cave Safety, did say that if it’s a limestone mine, that kind of mining is exempt from any state mine safety regulations, so their program does not inspect them.

Neither Mine and Cave Safety nor the Missouri Department of Natural Resources had specifics on the particular issue impacting that area, but did provide some general insight.

Attebery said that if the mine is re-purposed, meaning not currently engaged in mining, then it isn’t inspected for miner safety by the Mine Safety and Health Administration. So, it’s possible the mine is not inspected routinely, he said.

Austin Rehagen, abandoned mine land unit chief at Missouri Department of Natural Resources, said some mines sit for hundreds of years with no negative impact, saying, “Sometimes it’s not an issue until it is an issue.”

There aren’t many active inspections of mines in Missouri unless there are public complaints, he said. It’s not known how MoDOT was initially informed of this issue, and whether it could have been due to a public complaint about a mine.