Omya seeks OK on plan to handle marble waste
PROCTOR — Omya Inc. announced Monday it is seeking state approval to deal with chemically treated marble waste from its Florence calcium carbonate plant.
Omya filed an application for interim certification of its plan with the Agency of Natural Resources to use what's referred to in the mining industry as paste technology to dispose of its future marble waste or tailings.
The tailings, which contain chemical residues used in the calcium carbonate manufacturing process, have been stored in old quarries near the plant for the past 25 years.
Although company officials have repeatedly said the waste poses no health or environmental risk, neighbors have expressed concern that the chemicals could leach into groundwater or the nearby Otter Creek.
In June, several neighbors, with the help of the Environmental and Natural Resources Law Clinic at Vermont Law School, sued the company in federal court seeking to stop Omya from further dumping its waste.
James Reddy, Omya's president for North American Operations, said use of the technology would deal with future tailings, eliminating most of the water in the marble waste, which is then recycled back into the plant.
"We recover about 90 percent of the water and it goes right back into the plant and we continue to use it over and over again," Reddy said.
When a small amount of clay is added to the remaining waste, a paste-like substance is left over that dries quickly, binding the chemical residues making it safe to store, he said.
"It's as impermeable as a clay liner that you'd put at the bottom of a municipal waste landfill," Reddy said.
He said interim certification, which is good for two years, would allow the company time to transition to new disposal regulations. He said the company would also need time during that period to apply for an Act 250 land use permit to build its treatment facility.
While calling Omya's proposal a "positive step," Pat Parenteau, a lawyer with the Environmental and Natural Resources Law Clinic, said Omya would never have taken action to address the problem if not for the pressure from its neighbors.
"… If it weren't for the legal pressure that the residents, through our help, have brought to bear on the state, they would have continued dumping these tailings into these quarries until they were finished," Parenteau said.
The state Health Department concluded nearly two years ago that chemicals found in monitoring wells near the Florence plant in Pittsford were "at levels of regulatory concern."
Those chemicals include tall oil, which is used as a flotation agent to separate the tailings from the calcium carbonate product, biocides (used as a preservative), acetone, tolune, chloroform, and lubricating oil.
Based on the potential threat, the Department of Environmental Conservation ruled in April that Omya's tailings require a solid waste facility certification.
If Omya's treatment and disposal plan receives state approval, Reddy said the company would invest in the neighborhood of $10 million in paste technology equipment, including a dewatering facility at the plant that would siphon the water from the marble waste.
As far as the 25 years' worth of tailings that have been stored on site, Reddy said the company is exploring the prospect of using that calcium carbonate to neutralize the acid waste at the Ely copper mine site in Vershire. He also said the Elizabeth copper mine in Strafford is also a potential site as well. Both sites are on the Environmental Protection Agency's Superfund list.
Reddy said Golder Associates, the company's consultant, and the EPA are conducting a study at the University of Vermont to determine the feasibility of using Omya's tailings to neutralize the acid mine drainage at the Ely site.
Since half the tailings consist of calcium carbonate, he said, another other possibility is to come up with a method to recover the calcium carbonate from the existing tailings.
If neither alternative proves feasible, Reddy said, the tailings "will stay there until we can figure out how to recover it or find another use for it."
Parenteau said if the tailings could be used at the old copper mines, "that could be a good solution to a couple of different problems but we have to await some further testing to see if that might work."
While the interim certification process is conducted administratively without a public hearing, Reddy said Omya is seeking public input.
"We requested a public hearing because we thought it much better to get this it out in the open and discuss it right from the start rather than do this behind closed doors," he said.
Calcium carbonate is used as a filler or extender in the paint, paper, plastics, food and pharmaceutical industries. The company's North American headquarters is located in Proctor.
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