Final environmental impact statement Blackfoot Bridge Mine Caribou County, Idaho : Lead Agency: U.S. Department of Interior, Bureau of Land Management, Idaho Falls District, Pocatello Field Office

2011·198.4 MB·English

by  United States. Bureau of Land Management. Pocatello Field Office

0
BUREAU OF LAND MANAGEMENT
Take Pride*
Idaho Falls District Office
•N^MERICA
1405 Flollipark Drive
Idaho Falls, Idaho 83401
http://www.id.blm.gov
Dear Reader:
Enclosed for your review is the Final Environmental Impact Statement (FEIS) for P4 Production, EEC's (P4)
(a wholly owned subsidiary ofMonsanto Company, Inc.) Blackfoot Bridge Mine. This FEIS was prepared
by the Bureau ofLand Management (BLM), with cooperation from U.S. Army Corps ofEngineers, Idaho
Department ofEnvironmental Quality and Idaho Department ofLands. It analyzes the direct, indirect, and
cumulative effects ofmining operations for 17 years. The proposed Blackfoot Bridge Mine consists ofthree
open pits, haul roads, water management structures, and overburden disposal areas located approximately 1
miles northeast ofSoda Springs in Caribou County, Idaho. Public scoping meetings were held on February
28, 2006, and March 1, 2006. The Proposed Action, two different mining alternatives, and a No Action
Alternative were analyzed, and fifteen other alternatives were considered but dismissed.
Public comment on the Draft EIS was extensive and in consideration ofthose comments and additional
information, modifications were made and responses to comments were incorporated into this Final EIS.
The Final EIS has been prepared as a complete full-text document, and is being distributed either as hard
copy, compact disc, and is also posted at http://www.blm.g0v/id/st/en/prog/O.html.
BLM
Concurrent with this distribution, the filed the Final EIS with the U.S. Environmental Protection
Agency (EPA). EPA will then publish a Notice ofAvailability (NOA) in the Federal Register. On the
NOA
publication date ofthe EPA’s in the Federal Register, a 30-day availability period will commence. In
addition to the EPA’s NOA, BLM will publish a separate NOA with additional information in the Federal
BLM
Register and in local newspapers. Following the close ofthe availability period, will issue a Record of
Decision (ROD). Copies ofthe ROD will be mailed to people and entities on the Blackfoot Bridge Mine
mailing list. Notices ofthese decisions will be published in local newspapers. The ROD will have an
ROD
appeal period before the decision becomes effective. The will contain the appropriate instructions for
appeal.
The Final EIS is a completed document. Ifyou have information for agency consideration in making our
decisions, it can be sent to the following address and must be received by the end ofthe availability period:
Bureau ofLand Management, Pocatello Field Office, Attention: Blackfoot Bridge EIS Project Manager,
BLM
Pocatello Field Office, 4350 Cliffs Drive, Pocatello ID 83204, e-mail address:
[email protected].
Ifyou would like further information on this project, questions can be directed to Kyle Free, EIS Project
Manager, [phone].
Sincerely,
Joe Kraayenbrii
BLM Idaho Falls District Manager
4
;
i
• f
’i
VIS
V r
I
^»;
').
.
^.ia
(0?^OC9G2g
•hrN N
«50r.
FINAL
ENVIRONMENTAL IMPACT STATEMENT
BLACKFOOT BRIDGE MINE
LEAD AGENCY: U.S. Department of the Interior
Bureau of Land Management
Idaho Falls District
Pocatello Field Office
COOPERATING AGENCIES: U.S. Army Corps of Engineers
Idaho Department of Environmental Quality
Idaho Department of Lands
PROJECT LOCATION: Caribou County, Idaho
DATE FINAL EIS FILED WITH EPA: March 2011
QUESTIONS ON THE FINAL Kyle Free
EIS CAN BE DIRECTED TO: EIS Project Manager
BLM
Pocatello Field Office
4350 Cliffs Drive
Pocatello, Idaho 83204
ABSTRACT
This Final Environmental Impact Statement (FEIS) analyzes impacts related to mining phosphate ore at the
Blackfoot Bridge Mine in Southeastern Idaho. The Proposed Action includes developing three mine pits,
haul roads, water management structures, and overburden disposal areas. Use of existing mill facilities
would continue in Soda Springs. Alternatives to the Proposed Action are also analyzed and site-specific
mitigation measures developed. The BLM Preferred Alternative is Alternative 1A because the cover design
and water management plan would reduce the impacts ofthe Proposed Action.
RESPONSIBLE OFFICIAL FOR FEIS: Joe Kraayenbrink
BLM Idaho Falls District Manager
EIS NUMBER: ID-320-2006-EIS-1553
I
i
c
’'S'»
I I . • !fJ
' _ 'rt..> . .‘i(
I .->/•, .
,.i >
I
4
i
1
EXECUTIVE SUMMARY
The following information is provided as a summary of the analyses that have been conducted
for the Blackfoot Bridge Mine Project. However, this summary is not a substitute for review of
the complete Final Environmental Impact Statement (FEIS).
PROPOSED ACTION
ES.1
This FEIS was prepared by the Bureau of Land Management (BLM), Pocatello Field Office, in
cooperation with the Idaho Department of Environmental Quality (IDEQ), Idaho Department of
Lands (IDE) and the Walla Walla District of the U.S. Army Corps of Engineers (USAGE) in
response to the proposed Mine and Reclamation Plan submitted by P4 Production, EEC (P4) (a
wholly owned subsidiary of Monsanto Company, Inc.). P4 submitted an initial Mine and
BLM BLM
Reclamation Plan to the in November 2005. In October 2008, the received the
Revised Blackfoot Bridge Mine and Reclamation Plan (2008 Revised Mine Plan) from P4. The
2008 Revised Mine Plan (and subsequent modifications) includes details of operational and
reclamation activities proposed for the Blackfoot Bridge property. The 2008 Revised Mine Plan
proposes a new open pit phosphate mining operation on federal mineral leases that would include
external overburden piles, a haul road, and a water management plan. Processing would be
conducted off site. Mining would also employ best management practices (BMPs) for control
and prevention of releases of sediment, dissolved constituents, and trace elements, such as
selenium, to nearby surface water and groundwater. P4 has also applied for lease modifications
to include portions of the phosphate deposit that lie outside the current 1-05613 and 1-013709
lease boundaries, and requested that additional acreage be added to the application for lease
modification in May 2008. The proposed lease modification is addressed in the 2008 Revised
BLM
Mine Plan, and P4 requested that the include it in this environmental analysis.
The project area is located in Caribou County, approximately 10 miles northeast ofSoda Springs,
BLM
Idaho. The Proposed Action would occur on land with surface rights administered by the
and three private landowners. All phosphate mineral rights in the project area are administered
by the BLM. The leases convey to P4 the exclusive right and privilege, subject to the terms and
conditions ofthe lease, to explore and develop the federally owned mineral estate and to use the
surface offederal lands for related mine activities.
Under the Proposed Action, phosphate ore would be mined and hauled approximately 8 miles to
P4’s Soda Springs elemental phosphorus plant for processing. No processing facilities other than
typical crushing and screening operations would occur on the mine site. All chemical processing
activities would occur at the Soda Springs plant. The ore to be mined under the Proposed Action
is expected to be similar to that produced at other P4 mine properties in the area.
The Blackfoot Bridge Mine ore reserve would be developed using an open pit mining method on
a series of bench cuts, using a combination of in-pit retreating ramps and backfill ramps. The
primary equipment for ore and overburden mining would be a combination of trucks, track-
mounted excavators, bulldozers, and front-end loaders. A track-hoe excavator would also be
used to maximize recovery ofore in the bottom ofthe pit (pit crotch).
March 201 ES-1 BlackfoolBridgeFinedEIS
1
ExecutiveSummary
The Blackfoot Bridge Project would be mined in a phased approach with mining and reclamation
activities continuing for 17 years. Ore would be recovered from three separate mine pits: North,
Mid, and South Pits. Mining would begin in the Mid Pit, followed by the North Pit and South
Pit. All overburden would either be backfilled into mined-out portions ofthe mine pits or placed
in the external East Overburden Pile (EOP) or Northwest Overburden Pile (NWOP). Other mine-
related facilities would include: (a) ore stockpile and tipple (truck loading area); (b) ore truck
turnaround loop and equipment yard; (c) a water management system; (d) topsoil stockpiles; (e)
A
roads; and (f) water control ponds. water diversion ditch would be constructed from the
unnamed tributary to Fish Pond at EPl to the water management ponds; the water collected in
this system would be surface water runoff(Figure 2.3-1).
Surface disturbance resulting from the Proposed Action would total approximately 739 acres,
including 361.4 acres from pits, 185.8 acres from overburden piles, 86.8 acres from roads and
related facilities, 66.9 acres from water control ponds, and 38 acres from topsoil stockpiles.
Reclamation would take place over the life of the mine, with approximately 674 total acres
eventually being reclaimed. The remaining 65 acres of highwalls and similar areas with steep
slopes would be impractical to place soil and revegetate and, therefore, would not be reclaimed.
Detailed discussions of mine design, sequencing, and development and ancillary facilities
development are discussed in detail in Section 2.3 ofthis FEIS, as well as in P4’s 2008 Revised
Mine Plan. Cross-sections ofthe mine pits are also presented in the 2008 Revised Mine Plan.
Measures that would be employed to reduce environmental effects are described in detail in
Chapter 2 of this FEIS and would generally include: topsoil salvage and conservation;
implementation of BMPs for control of releases of selenium and other constituents of potential
concern (COPCs); implementation of a project-specific water management plan and stormwater
pollution prevention plan (SWPPP) measures for runoff and sedimentation control; use of oil
spill prevention control and countermeasures (SPCC); mitigation of wetland impacts; a Bald
Eagle Management Plan; and covering segregated Meade Peak overburden in the EOP with a
low-permeability cover system.
The Proposed Action would involve installation of the Simple 1 cover design to be used as a
cover for the segregated Meade Peak overburden placed in the EOP (approximately 35 acres).
The Simple 1 cover design consists of 18 inches of topsoil overlying 1 foot of weathered
alluvium and 2 feet of run-of-mine (ROM) chert. The remaining disturbance areas would be
covered using a base cover design consisting of at least 4 feet of chert or limestone, overlain by
18 inches oftopsoil.
ES.2 ALTERNATIVES
Along with the Proposed Action, three alternatives were evaluated in the FEIS and are described
in Sections 2.4 and 2.5. They include:
• Alternative lA - geosynthetic clay laminate liner (GCLL) cover system over core
materials in EOP and overburden in pits;
• Alternative IB - GCLL over entire EOP and overburden in pits; and
• No Action Alternative.
March201 ES-2 BlackfootBridgeFinalEIS
1
ExecutiveSummary
Fifteen other alternatives were also considered and eliminated from further evaluation in this
FEIS (Section 2.7).
ES.2.1 Alternatives 1A and 1B - Capping of Overburden and Backfilled Areas
Alternatives lA and IB were developed to address the issue ofthe potential for selenium to leach
into the groundwater. These alternatives are essentially the same as the Proposed Action, except
that P4 would construct a layer of impermeable material between the segregated Meade Peak
overburden and the applied growth medium to eliminate potential effects of water infiltrating
into the backfilled pits and external overburden piles. Alternatives lA and IB would also include
a modified water management plan that differs in many details from the Proposed Action. The
Blackfoot Bridge property for Alternatives lA and IB is slightly larger than the Proposed Action
property boundary due to south end diversion ditches. This revised boundary encompasses 1,483
acres and includes 634 acres of Federal Phosphate Lease 1-05613 and 80 acres on 1-013709,
covering subsurface mineral rights. There is approximately 1,074 acres ofP4 owned land within
BLM
the project boundary. Other private landowners hold 178 acres. The administers 231 acres
ofpublic land within the project boundary.
The GCLL cover system design consists of(from surface to depth):
• 18 inches oftopsoil;
• 1 foot ofweathered alluvium cover material;
• 0 to 6+ inches ofdrainage layer (actual thickness dependent on slope and aspect);
A GCLL
• layer (sodium bentonite encased between two geotextiles and a laminate layer);
• 6 inches of a protective subgrade layer (weathered alluvium or other earthen material);
and
ROM
• overburden.
Environmental mitigation measures and the Environmental Monitoring Plan (Appendix A)
included for the Proposed Action would also apply to these alternatives.
ES.2.2 Alternative 1A - GCLL Cover System Over Core Materials in EOF and
Overburden in Pits
Alternative lA involves placing a combination ofthe GCLL cover system over 383 acres and the
Simple 1 cover system over the remaining 99 acres of overburden pile. The 383 acres covered
with the GCLL cover system design would include:
• 86 acres covering the 35 acres of segregated Meade Peak overburden core associated
with the LOP;
• 63 acres ofoverburden associated with South Pit;
• 110 acres ofoverburden associated with Mid Pit; and
• 123 acres ofoverburden associated with North Pit.
March 201 ES-3 BlackfootBridgeFinalEIS
ExecutiveSummary
The 99 acres covered with the Simple 1 cover system design consists of:
• 45 acres ofexternal overburden associated with the NWOP; and
• 54 acres ofexternal overburden associated with the HOP.
ES.2.3 Alternative 1B - GCLL over Entire EOP and Overburden in Pits
Alternative IB involves placing the GCLL cover system over the entire 141 acres ofthe EOP, in
addition to 296 acres of backfilled pits for a total of 437 acres. The GCLL cover system design
would include:
• 141 acres external overburden associated with the EOP;
• 63 acres external overburden associated with the South Pit;
• 110 acres external overburden associated with the Mid Pit; and
• 123 acres external overburden associated with the North Pit.
The Simple 1 cover system design occupies 45 acres covered only within the NWOP.
ES.2.4 No Action Alternative
Under the No Action Alternative, the Blackfoot Bridge Mine would not be approved for mining
or any associated development on the existing leases. Similarly, the lease modification request
would not be approved. As a result, the No Action Alternative would not provide ore for P4’s
processing plant and would leave the mineral resource unmined. However, the No Action
Alternative does not imply that the leases would never be developed, only that they would not be
developed under this 2008 Revised Mine Plan. Another Mine and Reclamation Plan for these
two leases could be submitted in the future.
ES.3 AGENCY PREFERRED ALTERNATIVE
The BLM, IDL, and the IDEQ prefer Alternative lA as the Agency Preferred Alternative
because it employs measures to satisfy regulatory requirements and reduce potential
environmental impacts on regional water quality. The USAGE is neither an opponent nor a
proponent ofthe applicant's Proposed Action or alternatives.
ES.4 ENVIRONMENTAL EFFECTS
ES.4.1 Proposed Action and Alternatives
The environmental effects of the Proposed Action were evaluated and compared to the
alternatives in Chapter 4. A summary of the primary environmental effects of the Proposed
Action and Alternatives lA and IB is shown in Table 2.8-1. The environmental effects of the
Proposed Action and alternatives are summarized in the following narrative.
March2011 ES-4 BlacirfootBridgeFinalEIS
A
1
ExecutiveSummary
ES.4.1.1 Geology, Minerals, andPaleontology
Removal of91 million bank cubic yards (bey) ofoverburden would be a long-term, major, local
effect on these resources. All phosphate ore recovered from the project area would be transported
to the tipple facility for shipment to P4’s processing facilities at Soda Springs.
Under the Proposed Action, geologic and mineral resources in the North, Mid, and South Pit
areas would be directly affected by the removal ofphosphate ore and overburden. Mining would
result in a long-term local effect on resources that could be affected by release of selenium and
trace metals associated with mining and exposure ofthese materials to oxygen and precipitation.
Construction of mining facilities, such as roads, topsoil stockpiles, and water control ponds,
would have effects on the topography and stability of the landscape. The mining of ore and
overburden under the Proposed Action would expose currently undisturbed and buried rock to
weathering processes.
Existing topography would be affected under the Proposed Action by the removal of ore,
A
relocation of overburden, and construction of ore staging areas. total of 739 acres of existing
topography would be modified under the Proposed Action including haul roads and topsoil
stockpiles. Effects on topography would have major short-term effects and the 65 acres not
A
reclaimed would represent long-term modification. potential for minor instability ofslopes due
to the reclaimed landscape for roads, overburden piles, and mine pits may exist.
Removal ofoverburden and ore could affect paleontological resources. Damage to or destruction
of paleontological resources would not be likely; however, appropriate requirements would be
implemented as directed by agencies. The greatest potential for impact to surface and subsurface
fossils would come from excavations ofsurface deposits or bedrock. Both surface and subsurface
invertebrate fossils could be damaged or destroyed during ground-disturbing activities.
Expanded use ofthe GCLL and Simple 1 cover systems under Alternative lA would require an
increase of about 1 million bey of cover material for construction compared to the Proposed
A
Action. total of768 acres ofexisting topography would be modified under the Alternative 1
and 65 acres not reclaimed. The source of this additional material would be within the
disturbance footprint of the proposed pits and overburden piles. Replacing the Simple 1 cover
system with the GCLL cover system across the entire EOP under Alternative IB would require
the same volume of “weathered alluvium” for construction as under Alternative lA. Effects to
other geologic, mineral, topographic, and paleontological resources would be similar in scale and
extent as under the Proposed Action.
Under the No Action Alternative, mining phosphate ore would not be approved under the 2008
Revised Mine Plan currently submitted by P4.
A
ESo4.1.2 ir Resources
The Proposed Action would result in effects to air quality during drilling, blasting, excavation,
materials handling, ore crushing and screening, and vehicle operations. Design elements have
been devised that would reduce impacts to air quality. Construction activities would result in
short-term, minor effects to air quality. Minor annual fugitive dust emissions from mining
operations are estimated at 138 tons/year, and minor gaseous emissions from fuel combustion
March201 ES-5 BlackfuolBridgePinalEIS
1
ExecutiveSummary
and explosives are expected due to vehicle traffic and material handling activities; however,
these emissions would not be expected to increase over current emission levels associated with
operations at the South Rasmussen Mine. As mining operations begin at the proposed Blackfoot
Bridge Project, mining would cease at the South Rasmussen Mine.
Effects to air quality under Alternative lA would be the same as Alternative IB. Construction of
cover materials would result in an increase in effects to air quality for all criteria pollutants due
to increased vehicle traffic on unpaved roads and materials handling activities. Overall, effects to
air quality under Alternatives lA and IB would be expected to have a minor increase compared
to air quality under the Proposed Action.
Under the No Action Alternative, air emissions from the Proposed Action or alternatives would
not occur. Additionally, the No Action Alternative would result in declining effects to regional
air quality over time, as the South Rasmussen Mine would also be depleted and closed.
ESA.1.3 Noise
Sensitive noise receptors include residential areas, schools, and hospitals. The nearest residences
are located at a distance ofapproximately 1.5 miles from the project boundary. Other residences
are located several miles south ofthe project area toward Soda Springs.
Minor noise levels would be below the Environmental Protection Agency (EPA) guideline of 55
decibels above reference noise, adjusted (dBA) for each source (except blasting) at nearest
sensitive noise receptors. Noise from open pit mining is estimated to be below 55 dBA at a
distance between 1,920 and 3,840 feet, and noise from haul traffic and a conveyor is estimated to
be below 55 dBA at a distance between 480 and 960 feet.
Short-term blasting noise would exceed 55 dBA at nearest sensitive noise receptors. This does
not account for natural attenuation ofnoise when blasting is occurring below grade in the pit and
additional attenuation ofnoise due to natural topography and vegetation. Blasting is estimated to
occur 120 times per year and only during daylight hours. Noise effects from blasting would be
moderate.
Construction of cover materials under Alternatives lA and IB would result in a temporary
increase in noise effects due to increased vehicle and materials handling activity. Overall, effects
of noise under Alternatives lA and IB would have a minor increase compared to noise levels
under the Proposed Action.
Under the No Action Alternative, noise in the project area would remain at background levels.
ES.4.1.4 Climate
The Proposed Action and alternatives related to mining activities would result in greenhouse gas
emissions but would have a negligible contribution to climate change.
Under the No Action Alternative, generation of greenhouse gases associated with the Proposed
Action would not occur.
March201 ES-6 Blad^botBridgeFinalEIS