Skip to Content


Notice of Availability of Draft Environmental Impact Statement for the Proposed Blackfoot Bridge Mine, Idaho

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Bureau of Land Management, Interior.


Notice of availability.


In accordance with the National Environmental Policy Act of 1969 (NEPA, 42 U.S.C. 4321 et seq.), the Bureau of Land Management (BLM) has prepared a Draft Environmental Impact Statement (DEIS) for the proposed Blackfoot Bridge Mine and by this Notice is announcing the opening of the comment period.


To ensure comments will be considered, the BLM must receive written comments on the Blackfoot Bridge Mine DEIS within 45 days following the date the Environmental Protection Agency publishes the Notice of Availability in the Federal Register. The BLM will announce future meetings or hearings and any other public involvement activities at least 15 days in advance through public notices, media news releases, and/or mailings.


You may submit comments by any of the following methods:

Copies of the Blackfoot Bridge Mine DEIS are available in the BLM Pocatello Field Office at the following address: 4350 Cliffs Drive, Pocatello, ID 83204. In addition, an electronic copy of the DEIS is available at the following Web address:​id/​st/​en/​prog/​0.html.

Start Further Info


Kyle Free, Bureau of Land Management, Pocatello Field Office, 4350 Cliffs Drive, Pocatello, Idaho 83204, phone (208) 478-6368, fax (208) 478-6376.

End Further Info End Preamble Start Supplemental Information


P4 Production, LLC (P4), a subsidiary of Monsanto Company, holds mineral leases issued by the United States granting them exclusive rights to develop phosphate minerals in the Blackfoot Bridge area. P4 has submitted a Mine and Reclamation Plan (MRP) for BLM to consider the environmental impacts that may occur from implementation of the MRP, including the possible modification of existing leases. P4 must receive approval of the MRP and obtain additional Federal and state permits prior to mining under the proposed mine plan. The BLM has prepared a DEIS to evaluate effects of the Blackfoot Bridge Mine upon the human environment, including the potential effects of selenium and other contaminants, and to consider appropriate mitigation measures.

As required by the Mineral Leasing Act of 1920 and 43 CFR Part 3590, the BLM is to evaluate and respond to the MRP from P4 that proposes the recovery of phosphate ore reserves contained within Federal Phosphate Leases I-05613 and I-013709. The BLM is required to evaluate the MRP, considering the no action alternative and other reasonable alternatives, and issue decisions related to development of the phosphate leases and whether to modify the existing leases. The U.S. Army Corps of Engineers is required to evaluate and respond to P4's application for a permit under Section 404 of the Clean Water Act that is needed to implement the MRP. The DEIS provides the analysis upon which the BLM and other involved agencies can base such decisions. The Proposed Action is needed to ensure economically viable development of the phosphate resources, as required by Federal law and the Federal leases, and to allow the lessee to exercise its right to develop the leases mentioned above.

The Proposed Action consists of P4's MRP as revised in 2008. The Blackfoot Bridge Mine would be developed using open pit mining methods to extract phosphate ore that would be hauled about 8 miles to P4's existing Soda Springs elemental phosphorus plant for processing. Ore would be recovered from three separate mine pits called the North, Mid and South Pits. Mining would begin in the Mid Pit, followed by the North Pit and South Pit. Mining of the North Pit and portions of the Mid Pit are predicted to extend below groundwater level and would require dewatering during portions of the 17-year mine life. All overburden would either be backfilled into mined-out portions of the mine pits or placed in the external East Overburden Pile (EOP) or Northwest Overburden Pile (NWOP). Other mine-related facilities would include an ore stockpile, a tipple (truck loading facility), an ore truck turnaround loop, an equipment yard, two water management ponds, topsoil stockpiles, roads and sediment control structures. Approximately 739 acres of surface are expected to be disturbed over the life of the project, with about 640 acres (85 percent) planned to be re-vegetated. Fifteen percent of the mine site would involve residual highwalls that cannot be re-vegetated.

As phosphate mining has developed in southeast Idaho, increasing concern for surface and groundwater contamination has led to the development of various Best Management Practices (BMPs) to control potential selenium migration from the mines. An impermeable or low-permeability cover over external overburden piles and over pit backfilled areas is a way to reduce infiltration into the materials, and thus, reduce the potential leaching of selenium from the materials.Start Printed Page 41158

In the Proposed Action, pit backfills and overburden piles are to be covered with at least 4 feet of chert or limestone, overlaid by 18 inches of topsoil. A cover called the Simple 1 cover, consisting of 18 inches of topsoil overlying 1 foot of weathered alluvium and 2 feet of chert, is proposed for capping of seleniferous portions of the EOP. As part of the DEIS analysis, groundwater modeling has been used to estimate the potential effects of the proposed action on groundwater and surface water resources in the project area. Model results indicate that the Proposed Action, as designed, has the potential to release selenium concentrations to groundwater and ultimately surface water in excess of the applicable water quality standard. To address this potential excess, alternative capping designs (Alternatives 1A and 1B) were developed to reduce the amount of meteoric water that would infiltrate through the backfilled pits and external overburden piles. The reduction in infiltration would result in a reduction in the volume of water that would leach through mine overburden thereby reducing the volume of water containing constituents of concern that could potentially affect the quality of area groundwater and surface water.

Alternatives 1A and 1B would be comprised of all components of the Proposed Action but would require P4 to install a layer of impermeable material (a laminated Geosynthetic Clay Liner or GCLL) between the seleniferous materials and the applied growth media to reduce the volume of water infiltrating into the backfill. The GCLL cover system would be comprised of the following materials (from surface to base):

  • 18 inches of topsoil;
  • 1 foot of weathered alluvium cover material;
  • Approximately 6 inches of drainage/protective layer material (actual thickness is dependent on slope and aspect);
  • GCLL;
  • 6 inches of a protective sub-grade layer (weathered alluvium or other earthen material); and
  • Run of Mine (ROM) overburden.

The GCLL itself includes a thin layer of powdered sodium bentonite clay sandwiched between two geotextile layers. A geotextile is a woven or nonwoven sheet material that is resistant to penetration damage. The top geotextile layer is laminated with a polyethylene geomembrane layer, providing an additional layer of protection (hence the name, Geosynthetic Clay Liner Laminate).

While Alternatives 1A and 1B primarily address water quality issues, additional alternatives to address other issues are also considered in the DEIS.

A Notice of Intent (NOI) to prepare this EIS was published in the Federal Register on February 3, 2006. Publication of the NOI in the Federal Register initiated a 56 day public scoping period for the Proposed Action that provided for acceptance of written comments. The scoping process identified concerns that included potential effects of the project on water resources; socioeconomic conditions; livestock grazing; reclamation and restoration; wildlife and vegetation; soils; threatened, endangered, and sensitive species; air quality; aesthetics; land use; visual resources; hazardous and solid wastes; tribal interests and cumulative effects.

It is currently expected that P4's existing South Rasmussen Mine will be depleted sometime in 2012. Because of operating requirements at the Soda Springs processing plant, it is necessary to bring Blackfoot Bridge Mine online in 2010. In years 1 through 4, a blend of ores from both South Rasmussen Mine and Blackfoot Bridge Mine would be required.

Three public meetings will be held, each an open house, from 7 p.m. to 9 p.m. The open houses will include displays explaining the project and a forum for commenting on the project. Public meetings will be held in the Soda Springs City Office Building, 9 West 2nd South, Soda Springs, Idaho; in the BLM Pocatello Field Office, 4350 Cliffs Drive, Pocatello, Idaho; and in the Tribal Business Center, Pima Avenue, Fort Hall, Idaho. Each of these meetings will be held within 30 days of this Notice. Alternatively, interested parties may contact the BLM Project Lead listed above for specific information regarding the public meetings. Written and electronic comments regarding the DEIS should be submitted within 45 days of the date of publication of the EPA's Notice in the Federal Register.

Please note that public comments and information submitted including names, street addresses and e-mail addresses of respondents will be available for public review and disclosure at the above BLM address during regular business hours (8 a.m. to 4 p.m.), Monday through Friday, except holidays.

Before including your address, phone number, e-mail address, or other personal identifying information in your comment, you should be aware that your entire comment—including your personal identifying information—may be made publicly available at any time. While you can ask us in your comment to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.

Start Signature

Karen Rice,

Associate District Manager.

End Signature End Supplemental Information

[FR Doc. E9-19416 Filed 8-13-09; 8:45 am]