Engineers recommend Lee’s Summit watch roads near quarry at risk of collapse

rpulley@lsjournal.comJanuary 8, 2014 

A report on the safety of roads adjacent to a undermined area in Lee’s Summit and a proposed quarrying operation suggests at least some risk of collapse of the mine under streets north of Interstate 470.

The draft report from Terracon Consultants Inc. did not imply any imminent hazard. But it did recommend the city take precautions to monitor road and mine conditions near city right-of-ways.

The report also said that provided there is carefully controlled blasting, subdivisions south of Interstate 470 should not be damaged by seismic waves.

The draft report, commissioned by the city and delivered in December, said the existing mine will continue to deteriorate over time and continuing roof failures should be expected, particularly where rock and soil over the mine roof is thin.

That includes several spots along Quarry Park, Noland and Clifford roads, the report said.

“Although all streets over a deteriorating underground mine can be considered ‘at-risk’ in our opinion, those areas having the highest risk would be those located over or near existing roof failures and those which traverse areas with thin overburden.”

Terracon’s report didn’t directly address whether active mining increases the likelihood of collapse. It recommended the city monitor road conditions.

There are a handful of residences and several businesses along those roads.

City Manager Steve Arbo did not respond to a request for an interview before the Journal’s deadline.

Flip Short, owner of the site and proposed quarry, said that his team has reviewed the draft.

Short owns land above an idle limestone mine that underlies a large area north and south of Intestate 470, west of Pryor Road.

He intends to use an open-pit mine to reclaim about 70 acres of the land north of I-470 for redevelopment, by removing the unstable roof and lowering ground level. He also plans to sell the rock mined in the process. The unstable nature of the mine is one reason he proposes removal of the rock. But opponents who live nearby contend that could destabilize other parts of the mine nearby and endanger their property.

Short said he has begun some preliminary site work in anticipation of a state permit and is “more certain today that this is the best approach for the community to address what is, in effect, an economic brownfield, valuable land for commercial development along an interstate highway in a community that is running out of space to develop commercial property.” A significant upside will be the taxes generated from development of the site, he said.

Short said Family Ranch is pleased the Terracon draft report confirms the company’s expert (URS Corporation) report regarding the mine’s present and future conditions, that it summarized the report by geologist Charles Spencer as recommending additional data be collected and monitoring of development activities.

That operation, known as Family Ranch, has applied for an open-pit mining permit with the Missouri Department of Natural Resources. The agency is taking written comments on the project until Jan. 18. The state’s Land Reclamation Commission could order additional hearings on the permit, either in Lee's Summit or Jefferson City.

The Family Ranch team said it is pursing the state permit, although it maintains that the MDNR initially told them one was not necessary. Short said his team is having discussions with MDNR and the federal Mine Safety and Health Administration, which has included site visits. He said the company will soon have up a website which will provide updates on the project and reclamation.

Terracon offered the city a range of options to consider, from starting with regular inspections of Quarry Park, Clifford, Lowenstein and Noland roads for signs of distress that indicate pending collapse.

Other options include more extensive and expensive steps for monitoring surface conditions of the mine where roof failures hare been reported, such as aerial mapping with LiDAR (a technology that uses reflected laser light), surveying the mine and its underground pillars in relation to the streets or installing sensors along the street to warn of potential collapse.

Another recommendation is to limit reclamation to a zone that’s defined by a 45-degree slope from the edge of the right-of-way, without further study of the effects of closer excavation.

It also said the city could infill the mine under the roads.

Opponents of the mining operation said Terracon’s report confirms their concerns. Terracon said it made a “desk top” review of prior reports on the quarry (including one prepared by geologist Charles Spenser on behalf of the opponents) and in October made a “limited” visual assessment of surface and subsurface areas along the roads.

Opponents complain excavation of some sort has started, next to Quarry Road, saying they’re observing jack hammering of rock.

“The city is not doing anything about it,” said Scott Blankenship, who owns a business next to the mine. “They’re ignoring us to allow him to continue working. Now they’re putting us in danger and they have the proof.”

Blankenship said the Missouri Department of Natural Resources told him it isn’t able to take action unless Family Ranch begins to sell rock without a state permit.

Blankenship and other opponents contend the operation is violating its special use permit because the operation hasn’t erected fencing around the excavation site alongside Quarry Road.

There is yellow tape and orange webbing at that site, but it is inadequate, Blankenship said.

Carol Siegrist, president of the Bent Tree Bluffs Homeowners Association, characterized the Terracon study as an “after thought” which summarizes earlier reports with no new investigation of the mine stability.

She said Terracon “implicitly” accepts the possibility that vibrations could destabilize the mine roof and essentially agrees with the monitoring recommendations of Spencer. She said the qualifier that “carefully” controlled blasting “does not inspire confidence that the homes located less than one-half mile from the quarry will be safe.”

“It is difficult to have any confidence that this developer will follow the rules and regulations as well as use recognized safe quarrying procedures,” Siegrist said. “Likewise it is difficult to trust the city to monitor and regulate this process. As residents of this city we continue to ask our elected officials to protect our interests.”

Brian Whitley, one of two council members who voted against the special use permit for reclamation, said in an interview that he has empathy for residents. He said he is waiting on city engineers for their response to the draft report and an action plan from the city administration.

Whitley said he thinks the Terracon report confirms some of the Spencer’s assertions, particularly regarding streets, He said he’s not suggesting there is any immediate danger or public safety concerns, because that’s the responsibility of engineers to determine.

“I don’t think it’s a clean bill of health, but it doesn’t mean anyone is going to die,” Whitley said.

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