Even though the Newmont Mining Corporation agreed to build a water treatment plant to manage waters infiltrating Grass Valley’s sewer system, no formal plans have been proposed, city staff told The Union.
Because no plant was constructed by a February 2013 deadline, Newmont’s $300,000 annual settlement payment to the city was increased to $375,000.
Those fines are meant to compensate the city for infiltrations that allegedly caused waste spills that, in turn, caused regulatory fines against the city, its officials have said.
Every drop that makes it into the city’s 54.4-mile water system costs the city money to treat before it is released from the treatment plant. And while cracked pipes in the main lines represent the city’s second largest source of added cost from infiltration, the main source is the former Empire Mine, owned by Newmont Mining Corporation.
“It’s all connected,” said Trisha Tillotson, the city’s senior civil engineer. “If you have infiltration, it affects all users.”
In a February 2009 settlement agreement with the city, Newmont agreed to construct its own treatment plant to keep water from flowing into the city’s system, in addition to a $4 million payment for past treatment cost and fines associated with sewage spills. To date, the company has paid the city more than $1.2 million, Tillotson said.
The Grass Valley treatment plant can handle 1.6 million gallons per day, of which Newmont contributes approximately 400,000 gallons each day, according to city officials.
“It’s almost a quarter of the total flow,” said Bjorn Jones, the city’s associate civil engineer.
While annual payments have helped pay for the cost of covering the extra Newmont water, the city doesn’t want to continue to treat that water, Tillotson said.
Mine water should not be put through a municipal treatment facility for an extended period of time, the city argued in a suit against Newmont.
Municipal plants operate with biological processes, whereas physical and chemical processes are used to remove metals from mine waste, said Jeffrey Foltz, the city’s interim administrator, in 2007.
“Lack of organic waste in the mine water and its acidity and cold temperature adversely affect the biological treatment and cost (Grass Valley) more to process,” Foltz argued nearly seven years ago.
“The bottom line is the Newmont wastewater does not belong in the city’s wastewater treatment plant.”
The city’s most recent treatment plant dump into Wolf Creek was in December 2012 as a foot of rain drenched Nevada County and the Sierra over a four-day period.
Of the approximately 450,000 gallons of untreated or partially treated wastewater that spilled into the creek, 136,500 gallons were recaptured.
The Water Quality Control Board slapped a $110,000 fine on Grass Valley after 10,000 gallons of wastewater spilled into Wolf Creek in October 2011. That spill came from near a Joyce Street lift station, not the treatment plant.
In June 2009, an estimated 10,000 gallons spilled into Wolf Creek as a result of a plugged valve and a monitoring system that failed to sound an alarm.
According to the state Water Resources Control Board, Grass Valley had a total of three violations in five years.
Grass Valley isn’t the only facility that has had recent spills. South County’s Lake of the Pines wastewater treatment plant released about 37,500 gallons of raw sewage into Magnolia Creek in January.
Beyond pointing to a 2009 settlement press release that noted that construction of the plant would be contingent upon regulatory approval, representatives of the Newmont Mining Corporation did not provide The Union with a requested status update on the progress of the treatment plant as of press time Tuesday.
Newmont officials met with the city six months ago for broad talks about the treatment plant, but Tillotson said they were far from concrete and no further talks had occurred nor had any plans been proposed.
Bids are expected to begin next week on a $250,000 project to add an inner lining to a stretch of Grass Valley sewers — one of dozens of projects aimed at blocking groundwater infiltration into the water system that is blamed for wastewater overflows into Wolf Creek.
“This is what (residents’) user rate fees go toward,” Tillotson said.
Water that leaks into the city’s pipes eventually makes its way to the wastewater treatment plant off Allison Ranch Road, on the west side of Wolf Creek.
“You can see water shooting in” to the pipes, Jones said.
While the injection of fiberglass liners into the cracked pipes between Morgan Ranch and Slate Creek lift station will incrementally reduce the leakage, there is much more to do, Tillotson said.
Of the city’s nearly 55 miles of sewers, little more than a mile and a half has been lined since the effort began a couple years ago, Jones said.
“We could do them every year for the next 60 years,” Tillotson said. “There is plenty we would like to do, funding permitting.”
To contact Staff Writer Christopher Rosacker, email firstname.lastname@example.org or call 530-477-4236.