By LeAnn R. Ralph
TOWN OF AUBURN — The Superior Silica Sand (Glaser Mine) north of Colfax on state Highway 64 in the Town of Auburn could start the first phase of reclamation this year.
Seth Ebel, Chippewa County environmental engineer, and Dan Masterpole, Chippewa County conservationist, spoke to the Auburn Town Board about the sand mine March 13.
Industrial sand mines covering more than 2,400 acres have received reclamation permits from Chippewa County and are already operating east and north of Colfax.
Additional permit applications are pending with Chippewa County for industrial sand mines covering another 850 acres.
Masterpole said the Chippewa County land conservation office plans to meet on an annual basis with townships that have sand mines.
Meetings have already been held with the Town of Howard and the Town of Cooks Valley, he said.
A total of five mine sites have been identified in the Town of Auburn, although so far, the sand mine right across the road from the Auburn Town Hall is the only one operating, Ebel noted.
The mining area in the Town of Auburn has several watersheds, including Sand Creek, Trout Creek and the Red Cedar River, Ebel said.
Auburn has streams that are rated as “high quality” waters and also has a couple of “exceptional” or “outstanding” waters, he said.
“There are quite a few really good water resources in Auburn,” Ebel said.
The 200-acre mine site has six groundwater monitoring wells and another seven monitoring wells will be required for a planned expansion of the mine, he said.
Information from the monitoring wells will be particularly useful for the five-year groundwater study, Ebel noted.
Elevations at the Glaser mine range from 1060 to 1080; the water table is located at elevation points between 1050 and 1090, he said.
The mine site has six settling ponds, and stormwater ponds at the mine site are designed to contain a one-hundred year rain event, Ebel said.
Superior Silica Sand uses eight million gallons of water per month, he said.
By comparison, Colfax uses an average of 2.5 million gallons per month, or 30 million gallons in a year. Glenwood City uses an average of 2.4 million gallons per month, or 29.2 million gallons in a year.
The stormwater ponds will need to be cleaned out as necessary, and the mine site is required to have erosion control in place, such as silt fences, seeding, mulching and rock berms, Ebel said.
Because of all the monitoring required at the mine sites, Chippewa County must have a “continuous presence” at the sand mines, he said.
So far, the county has good working relationships with the mine operators, and the operators are willing to cooperate with the county, Ebel said.
Acrylamide is used as a “flocculent” (settling agent) in mining operations, and Chippewa County has been testing for acrylamide in the groundwater.
“Nothing has come back positive yet for acrylamide, only trace amounts,” Ebel said.
The federal Environmental Protection Agency has set a limit for acrylamide of .5 (one half of one part) for parts-per-billion in drinking water, he said.
One problem with testing for acrylamide is that no one is certain right now how fast the groundwater moves, Ebel said.
Groundwater movement is one aspect of the five-year groundwater study.
“We might not get the information we need for a few years,” Ebel said.
If, for example, the groundwater moves ten feet per year, and the acrylamide is 50 feet from the monitoring well, it might take five years for acrylamide to show up in the groundwater, he said.
Acrylamide is known to break down quickly when it is exposed to the air, Masterpole said.
The settling ponds have clay liners, and if acrylamide is in the material that settles out in the bottom, it would be of great benefit to stir it around and expose it to the air before it is used in reclamation, he said.
Masterpole noted that Chippewa County requires food-grade acrylamide to be used.
All top soil and sub-soil stays at the mine site so it can be used for reclamation, Ebel said.
The sloped areas of the mine will be turned into wildlife habitat and planted to trees when the mine is reclaimed, and the flatter areas will be turned into wildlife habitat with prairies and natural grasses, he said.
The mining companies are required to provide financial assurance; the bonding is necessary so that if the mine operator fails to reclaim the site, the county will have a funding source to do the reclamation, Ebel said.
The fine material coming out of the settling ponds contains aluminum, phosphorus and iron, but what remains to be seen is how much of it is biologically available, he said.
If the fine material is full of nutrients, it may be valuable in reclamation, Ebel said.
Some reclamation work will be completed this year at the Superior Silica mine, he said.
Reclamation science is particularly important because it helps determine what needs to be done to have a successful reclaim of a mine site, Ebel said.
“We are just at the beginning of the journey,” Masterpole said.
Each of the mines operating in Chippewa County are required to file an annual report with the Chippewa County Land and Forest Management office that includes a variety of information, such as the flocculants used and the amount of water used.
The annual reports are available in the land conservation office for inspection.
Mining permits, conditions set by the county, reclamation plans and public comments are all available on the Chippewa County website under Land Conservation and Forest Management.