CARLSBAD, N.M. (AP) — State environmental regulators are reviewing plans submitted by Mosaic Potash to investigate and define the extent of groundwater contamination from discharges associated with potash mining along the Pecos River in southern New Mexico.
The state Environment Department announced earlier this month that contamination had been detected in nearby groundwater monitoring wells between the company's Laguna Grande lake and the river. As a result, the company was required to submit a plan for monitoring and dealing with the pollution.
Potash mining is a main economic driver in Eddy County. A salt rich in potassium, potash is used mostly as a plant fertilizer and in animal feed.
Carlsbad was the site of potash’s first discovery in North America in 1925 during oil drilling, the Carlsbad Current-Argus reported. The discovery led to a boom in development in the former ranching town that predated the area’s prominence in fossil fuels.
Mosaic’s mine, about 16 miles east of Carlsbad, produces the ore both through its underground mining and surface operations.
Waste resulting from mining the ore is moved around the facility into multiple disposal areas, potentially leeching into groundwater supplies.
Extracting potash from underground generates tailings that are disposed of along with salty brine water. The salt and clay settle and the brine water and residual clay flow into a settling pond. The brine is then discharged from the pond through a pipeline into Laguna Grande, and then into evaporation cells where the resulting chloride salt is harvested.
Mosaic’s discharge permit allows for up to 7.5 million gallons (34 million liters) per day of tailings, brine and other liquids, including 29,000 gallons (109,777 liters) per day of untreated domestic wastewater.
These discharges have the potential, according to the state Ground Water Quality Bureau, to increase groundwater in the area to more than state standards for total dissolved solids, potentially impacting the Pecos River.
Should that happen, the Environment Department has the authority to close the facility and require Mosaic provide an immediate plan to mitigate the pollution.
The agency holds a bond with Mosaic for about $82 million to fund such a closure should elevated contaminant levels be detected.
Mosaic's discharge permit was last renewed in 2011. The permit includes the abatement plan that defines how the company reduces its environment impact.
Mosaic is required to collect water samples quarterly from several monitoring wells in the area and from the Pecos River, and report to the state on the levels of dissolved solids and other contaminants.
Once Mosaic characterizes the nature and extent of groundwater contamination from mine discharges between Laguna Grande and the Pecos River, the state may require the company to develop an more detailed abatement that outlines strategies to clean up the groundwater contamination.