Trinity plans to stay the course on trying to patch road sinkhole
By Ronnie Thomas
TRINITY — The prospect for a quick and inexpensive fix for Trinity's sinkhole on Old Alabama 24 sank at Monday's Town Council meeting.
After hearing a report from Town Engineer Sonny Wright on his meeting with expert Oscar Gay of TTL Laboratories, Mayor Vaughn Goodwin said the town "will keep doing what we're doing."
That would be, Vaughn said, to continue patching the hole with cold mix as the road dips and hope that it will eventually take hold.
Goodwin had met Nov. 27 with the state Department of Transportation's chief geologist, Willard L. Sitz, who suggested determining how far down workers could drill and hit solid ground. He said that if they could not get close, the town should consider digging beside the road and pumping in concrete to form a solid plug.
"He also would not guarantee that the method would work," Goodwin said at the time.
Wright on Monday said Gay told him workers should not drill more than 100 feet if they didn't strike bedrock because of the cost of $15 to $20 per foot.
"He told me you could spend $15,000 to $20,000 looking for rock and not find anything," Wright said. "He suggested getting in the middle of the area using an impact drill with a well casing, drilling to the bottom of rock and pumping in grout, extricating the casing as you go. You would pump the grout until you started getting resistance. "
Wright said the problem is "you can't tell how much grout will be needed because you could be into a bottomless pit."
Wright repeated what he had said previously, that Trinity is included in an area of "karst topography."
"Normally, the pattern runs from Birmingham to Kentucky and to the Chattahoochee River on the Alabama-Georgia border," he said. "In plain language, that topography means the bed-rock is broken and eroded."
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