Time proves ‘caving grounds’ stable

Off limits no more

By SAM EGGLESTON Journal Ishpeming Bureau
NEGAUNEE — When can land over abandoned mine shafts be considered safe?


The answer, it seems, is one that will take patience to discover.


When the question of why the former “caving grounds” in Negaunee and Ishpeming, closed by Cleveland Cliffs Inc. decades ago, were now considered safe, Marquette County’s mine inspector said time is the answer.


“If there’s going to be sinking and settling of the land, it’s usually within the first 15 or 20 years,” Mine Inspector John Carlson said. “Most of the land that CCI had closed off was never really in that much danger of caving in, but because they had underestimated the potential for sinking initially, they over compensated when they started closing off land.”


Carlson said that over compensation led to large tracts of land being closed off in the 1960s that really didn’t need to be. Those formerly fenced-in areas are now being opened by the city of Negaunee, which purchased the land from CCI in 2003 — the same deal in which the city of Ishpeming purchased former caving grounds.


But what’s considered safe and what’s still unstable?


“Anything that is still a hazard is closed off to the public,” Carlson said. “There is fencing around any of the open pit areas and where the ground is still considered likely to sink.”


One of the reasons the grounds were closed off in the first place was fear of cave-ins in the city of Negaunee. One area, known as “Old Towne,” was once home to a thriving part of the city. When the ground was recognized as unstable, the residents were asked to take their belongings — including their homes — and move. That area has been reopened to the public and the foundations, steps and sidewalks of the former neighborhood are still visible.


That land — which is being used for recreational purposes, including a section of the Iron Ore Heritage Trail — is one example of how the city of Negaunee is being careful to determine what property is good for specific purposes.


“The area that we just opened up is good for surface use, but not necessarily for buildings or structures,” Negaunee City Manager Gerald Peterson said. “In that area, we’ve taken some trees down to show where we can relocate Jackson Park and how certain pieces of land can be useful for different purposes.”


Peterson said property with open pits and underground shafts close to the surface will continue to be closed off because of the expectation they will eventually subside.


He said the city will follow a standard procedure to decide uses for property, determined after speaking with CCI officials and the county mine inspector. Areas with shafts between 100 and 1,500 feet below the surface will be used as parks and recreation areas but not for structures. Areas with shafts between 1,500 feet and 3,000 feet will be open for just about any use.


“The experts tell me that if and when it subsides, it won’t make it to the surface,” Peterson said. “The rocks won’t completely mat down and you wouldn’t get perfect compaction, so the surface won’t see any changes when it happens. That’s what they tell me at least.”


When Ishpeming decided to purchase the former CCI-owned land, city officials relied on studies that were done on the subsidence before moving forward.


“When ECI (Engineering Consultants of Ishpeming) did the reuse plan for the former CCI properties, with reports in there from a geological engineer named P.R. Bluekamp, the study indicated that the area’s subsidence had run its course,” said Al Bakalarski, Ishpeming city manager. “There is no additional subsidence anticipated in the areas we have opened up. There are some areas that are still considered caving grounds, but those are still fenced off and off limits.”


The two communities are moving forward with their plans for using the land. Negaunee, for example, recently clear-cut more than 100 acres and is expected to sell it off in seven parcels to developers and other interested parties.


Carlson said he believes the land is safe for use, although it can present challenges.


“It’s not easy having communities built on top of tunnels,” he said. “You really never know what could ultimately happen. The odds are nothing ever will. But if a big earthquake ever decided to come through the Upper Peninsula? Well, there just might end up being a big hole where Ishpeming, Negaunee and Marquette used to be.”


Without the occurrence of a Richter-Scale registering event, however, Carlson said he expects the areas around Negaunee and Ishpeming to be just fine.


“It’s been a long time and nothing has happened,” he said. “If it was going to sink, it would have done it already.”