The federal Bureau of Land Management has released a draft environmental assessment regarding Mosaic Potash Carlsbad’s plans to use a nearly 1,000 acre natural playa as a clay settlement facility.
The playa, known as Laguna Uno, has previously been used by the mine and, if approved, the mining company will use it as a secondary clay settling pond to reduce the amount of clay in the water that is discharged into an area known as Laguna Grande.
A 30-day comment period began Monday on the draft environmental assessment and will remain open through July 23.
The draft environmental assessment’s proposed action would allow Mosaic to use Laguno Uno as an additional clay settling pond.
BLM considered other locations as well as the no action alternative, which would result in the application being denied. The alternative locations for clay settlement would all result in a greater impact than Laguno Uno, the draft environmental assessment states.
Mosaic has been mining in the area since the 1970s and, prior to the construction of a clay settling dike in 2005, Laguna Uno was used as the mine’s primary clay settling area for runoff from the salt stack, according to the environmental assessment. Since 2005, Laguna Uno has only been used during maintenance of the clay settling pond or during upset conditions.
Mosaic is now seeking to use Laguna Uno in conjunction with a 150-acre existing clay settling pond to provide for more operational flexibility and to reduce the amount of brine that is discharged into Laguna Grande. Laguna Grande is about 4,500 acres and includes a lake, several salt harvesting ponds and a surface water settling pond. There are two salt mining operations that use Laguna Grande and could benefit from the reduction in brine discharged into it.
The draft environmental assessment states that the proposal to use Laguna Uno will lead to an increased deposition footprint that could impact up to 88 acres of public lands in Eddy County.
Some of the concerns about the proposal include its impact to a sensitive species of cactus as well as five cultural resource sites in the area. There are also concerns about impacts to groundwater and surface water and to shorebird habitat.
The environmental assessment states that a portion of Laguna Uno is within an area nominated to be designated as the Salt Playas Area of Critical Environmental Concern. This nomination was based on cultural, fish and wildlife resources.
However, the impacts to these resources can be limited through engineering controls and impoundment construction.
Comments can be submitted using ePlanning or by mail to the BLM Carlsbad Field Office, Attn: Robert Salaz, 620 E. Greene St. Carlsbad NM 88220.
“Review and comment periods provide an opportunity for the public to inform the BLM of any concerns they have regarding a proposed project,” said acting BLM Carlsbad Field Manager Dave Evans in a statement. “Please keep in mind that substantive, factual-based comments are the most helpful.”
