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water permitting strategy for mine

water permitting strategy for mine
Essar Steel Minnesota LLC

water-transfer solution will allow mine to operate with zero liquid discharge

Essar Steel Minnesota (formerly Minnesota Steel Industries) is building North America’s first completely integrated steelmaking facility—one that will mine and process iron ore and manufacture steel on the same site. The project is located in Nashwauk, on the site of an earlier mine and taconite plant that was dismantled in 1985.

Traditionally, industrial operations have drawn clean water from the ground, used it in their processes, and then discharged it to the environment—contributing at least minor levels of pollutants to water bodies. That approach wasn’t an option for the Essar project for two reasons: 1) a moratorium on the issuance of water-discharge permits in Minnesota had been put in place to halt the deterioration of water quality, and the project’s schedule couldn’t accommodate waiting for the moratorium to be lifted; and 2) lakes and streams in the area already exceeded federal clean-water standards for mercury and other pollutants, and new discharges were prohibited. A major key in obtaining approval to construct and operate the Essar facility was identifying a viable supply of water for process use while keeping stormwater and wastewater discharge from entering nearby water bodies.

Working with an environmental attorney, Barr devised an innovative solution. The three-part strategy, which called for transferring water among existing mine pits and lakes, relied on the concept that existing water-filled mine pits were not industrial in nature but “waters of the state,” because they had not been regulated by environmental permits since operations had ceased at the site 20 years earlier.

The first part of our strategy addressed the need to dewater an existing mine pit to enable further mining of ore from it. Barr demonstrated that dewatering the mine would not create additional discharge or pollution if the water were simply transferred from one location (the mine pit) to another (a nearby lake and stream). No new water would enter the ecosystem; only the conduit and rate would change.

The second and third pieces of the strategy involved collecting and storing stormwater runoff on site to use as process water, and keeping new pollution from entering existing waters during construction and operation of the mine and steel plant. Barr proposed creating a stormwater-containment system from several existing mine pits and a few new ponds. This design would not only prevent pollutants from entering existing waters, but also provide a plentiful supply of process water for the plant. Treating the facility’s post-process water with reverse osmosis and recycling it back to the plant would eliminate the buildup of salts in the tailings basin over time, and therefore the potential for additional groundwater contamination. In addition, treating and recycling the water all but ensured that even during extended drought periods, no clean groundwater would need to be tapped for mining and manufacturing operations.

State and federal agencies (the Minnesota Pollution Control Agency and Department of Natural Resources, and the U.S. Environmental Protection and Army Corps of Engineers) accepted our solution, allowing the $1.6 billion project to move forward with no permits for groundwater appropriation, surface-water discharge, or industrial stormwater runoff. The facility is expected to begin operations in 2017, creating about 600 permanent jobs and up to 2,000 spinoff jobs in the community.

For more about other services Barr provided on this project, see environmental review and permitting for mine project and engineering and environmental services for new mining facility.