Marion planning to test abandoned mine as a potential water supply
The small western Kentucky city of Marion has faced a critical water shortage for months, and now local officials are planning on testing water in a nearby abandoned mine as a potential short-term water supply.
The Lucille Mine in Crittenden County is a fluorspar mine that’s been abandoned inside the city limits since the 1930s. The community temporarily used it as a water source in the 1950s. Crittenden, Livingston and Caldwell counties, along with parts of southern Illinois, have historically been substantial producers of fluorspar – a mineral used to help produce steel, aluminum, refrigerants and more.
Marion City Administrator Adam Ledford said, since the water shortage crisis began, the city has considered and put aside using the mine as a water option two seperate times. The city, working with Illinois company C&C Pumps and Supply, plans to pump water out of the mine to see how quickly the naturally-occuring aquifer that intersects the mine fills it back up. How quickly the mine refills will help determine if it’s a viable water source.
“We'd be doing a disservice to the public not to at least go through the initial channels of attempting to understand what limitations or challenges it may present,” Ledford said.
But there are challenges with using the mine: tests of the water inside it showed high levels of iron, manganese and fluoride. A statement from the Kentucky Energy and Environment Cabinet – which houses the Kentucky Division of Water, the agency that would need to issue a permit for the mine to be pumped – said long-term exposure to high levels of fluoride can cause bone and dental disease, while lower concentrations of the mineral can cause tooth discoloration and tooth pitting.
Manganese and iron can give drinking water an “unpleasant” taste, odor and color, according to the statement, and the minerals can cause brownish-black and reddish-brown stains on porcelain, dishes, utensils, glassware, sinks, fixtures and concrete.
The U.S. Environmental Protection Agency sets legally enforceable standards for the maximum levels of contaminants – such as fluoride – allowed in drinking water. The federal agency also issues non-enforceable guidelines for secondary contaminants – such as manganese and iron – that may not cause health problems but create cosmetic or aesthetic effects in the water.
The maximum contaminant level in drinking water set for fluoride is 4 milligrams a liter (mg/L). Manganese and iron as secondary contaminants have suggested limits of 0.05 mg/L and 0.3 mg/L, respectively.
The city tested the mine water in June and found the levels of all three minerals exceeded the contaminant limits in the sample, which contained 4.4 mg/L of fluoride, 0.57 mg/L of manganese and 14.6 mg/L of iron.
But Ledford, the city administrator, said additional testing conducted on water from the aquifer outside the mine showed the fluoride levels to be below 1 mg/L. He believes once stagnant water is pumped from the mine, the fresh water that refills it could have much lower levels of minerals that could be treatable.
“It is very true that our [water] plants have no capacity for treating fluoride, taking fluoride out of water,” Ledford said. “That will be a moot point once we get the fresh water.”
Ledford said staff at the city’s water treatment plant are knowledgeable on treating iron and manganese in the water, though not at the levels seen in the mine samples. The cost of the technological processes that would be needed to filter these minerals is a lingering question.
“Can I treat it at a cost that is reasonable to our use?” Ledford said. “We believe we need to at least go that far down this route before we come to that conclusion.”
A statement from the cabinet spokesperson said reverse osmosis and activated alumina are considered the “best available technologies” to control fluoride in drinking water. Other technologies that could be used include ion exchange, lime softening, electrodialysis and adsorption of fluoride through activated carbon, bone chars and clays.
According to the statement, removing iron and manganese from the water would involve a process called oxidation.
“Oxidation involves the process of converting the soluble forms of iron and manganese into their insoluble forms for removal by sedimentation and filtration,” the statement said. “Most commonly, oxidation is achieved by injecting a chemical oxidant like permanganate into the treatment process.”
The cabinet spokesperson said the Division of Water needs adequate data to determine if a new water source is suitable, with more than 90 contaminants having to be quantified before state officials allow access to a new water source. Changes to the chemical treatments at the Marion water plant would have to be approved by the Division of Water, and the state public health department also has fluoride requirements that would need to be considered before approving the water source.
Evelyn Hayes, a Marion resident who’s been conserving water for months with her husband, wonders why the city hadn’t considered the possibility of using Lucille Mine earlier.
“They said they're gonna pump it dry and see how long it takes to fill up. But that should have been done in April before all this mess started to know we can use that as a water source if we have to,” Hayes said. “It's getting to the point I feel ridiculous.”
The city of Marion had looked at using the mine as a potential water source over a decade before the water shortage crisis. Following a 2007 drought which saw the water levels deplete at Lake George – Marion’s long-time primary water source that was drained in late April – city officials had asked the Kentucky Geological Survey to conduct a survey of the Lucille Mine to try to find shafts and other features below the ground. The mine survey of the shafts would then be used as reference points to drill test wells to see the viability of the mine as a raw water source. Marion public works employees in 2011 had dug shallow holes at the abandoned mine property to find two buried water wells associated with the mine.
According to the Kentucky Geological Survey report, preliminary testing of the mine water in the buried well showed it had a fluoride concentration of 3.5 mg/L.
“The city of Marion plans to have the dewatering well pumped to determine potential drawdown in the mine and to collect additional water samples during pumping to see if the quality of the mine water changes over time,” the research report stated.