The Nevada Department of Environmental Protection (NDEP) has made a preliminary determination to issue both a Water Pollution Control Permit and Mine Reclamation Permit for the proposed Thacker Pass Lithium Mine Project located approximately 18 miles northwest of Orovada in Humboldt County, north of Winnemucca in the McDermitt Caldera.
The public comment period for these proposed permits is open now until December 1, 2021 and NDEP will provide a response to all comments received from the public regarding the permits.
The public hearing for the Water Pollution Control Permit and Mining Reclamation Permit will be held on December 1, 2021 at 6 p.m. at the Boys & Girls Club of Winnemucca.
Lithium Nevada Corp (LNC) is the permittee for the Thacker Pass Project which consists of an open pit lithium mine, two waste rock storage facilities and associated runoff ponds, coarse gangue stockpile and runoff pond, sulfuric acid plant, processing plant, and clay tailings storage facility.
The water permit would not authorize mining below the regional water table and restricts mining to 15 feet above the regional water table (4,840 feet amsl) under part IG of the Permit, with the first 20 years of mining anticipated to occur above this elevation.
The water permit will allow the permittee to process up to 7,640,000 tons of ore per year.
In order to verify the water levels and ensure that mining will comply with the 15-foot buffer above the regional water table during operations, a series of at least two 300-foot deep standpipe piezometers will be drilled two years in advance of the current mining panel for monthly and quarterly reporting and monitoring, according to the draft permit.
After approximately four years of operation, the pit development will have advanced enough to accommodate a portion of the waste rock material being placed in the pit's backfill. Because mining is not initially planned below the water table, there will not be the potential to form a pit lake and pit backfill will be unsaturated.
Prior to mining below the water table, the permittee shall submit a groundwater model to evaluate the impacts and demonstrate waters of the state will not be degraded for division review and approval.
The Thacker Pass Project is required to be designed, constructed, operated, and closed without any release or discharge from the fluid management system except for meteorological events which exceed the design storm event.
According to the disturbance table located within the mining reclamation draft permit, the total mine pit shows a 1,099.8 acre disturbance, with approximately 371.1 acres during phase one and 728.7 acres in subsequent phases.
The clay tailings filter stack is proposed at 364.6 acres in phase one and 801.5 acres in subsequent phases, for a total of 1,166.1 acres total.
In all the project proposes 3,144.5 acres of disturbance in phase one and 2,400.5 in subsequent phases, for a total of 5,545.0 disturbance located on public lands administered by the Bureau of Land Management.
According to the draft permit limitations and requirements, drill holes will be plugged in accordance with the provisions specified in Chapter 534 of the Nevada Administrative Code and all drill hole cuttings, grout, and fluids shall be contained in sumps constructed at the drill sites and no more than four drill holes will remain unplugged at any one time.
On October 18, NDEP made a preliminary determination to issue an Air Pollution Control Permit for the Thacker Pass lithium mine, with public comment on that permit open until November 18.
There will be a public hearing on the proposed Air Pollution Control Permit on November 18, 2021 at 6 p.m. at the Boys & Girls Club of Winnemucca.
Comments on the proposed permit or recommendations of terms and conditions for consideration of incorporation into the permit can be submitted by mail to the Nevada Division of Environmental Protection, Bureau of Mining Regulation and Reclamation, 901 South Stewart Street, Suite 4001, Carson City, NV, 89701 or emailed to ndepthackerpass@ndep.nv.gov.
The full draft Water Pollution Control Permit can be found online at https://ndep.nv.gov/uploads/documents/NEV2020104dpFY22.pdf.
The full draft Mining Reclamation Permit can be found online at https://ndep.nv.gov/uploads/documents/0415_drpFY22.pdf.
