[Federal Register Volume 78, Number 165 (Monday, August 26, 2013)]
[Notices]
[Pages 52762-52764]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-20733]
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DEPARTMENT OF DEFENSE
Department of the Army, Corps of Engineers
Notice of Intent To Prepare A Draft Environment Impact Statement
for the Proposed Ray Mine Tailings Storage Facility in Pinal County,
Arizona
AGENCY: U.S. Army Corps of Engineers, DoD.
ACTION: Notice of Intent.
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SUMMARY: The U.S. Army Corps of Engineers, Los Angeles District (Corps)
is examining the environmental consequences associated with the
[[Page 52763]]
proposed construction, operation, and closure of a new tailings storage
facility in eastern Pinal County, Arizona, in connection with Asarco
LLC's application for a Department of the Army permit under Section 404
of the Clean Water Act. The proposed tailings storage facility and
associated facilities would discharge fill materials into approximately
138 acres of waters of the U.S. and indirectly impact an additional 17
acres through dewatering. The primary federal environmental concerns
are the proposed discharges of fill material into waters of the U.S.
and the potential for significant adverse environmental effects
resulting from such activities. Therefore, to address these concerns in
accordance with the National Environmental Policy Act (NEPA), the Corps
is requiring preparation of an Environmental Impact Statement (EIS)
prior to consideration of any permit action. The action must comply
with the Section 404(b)(1) Guidelines (40 CFR Part 230) and not be
contrary to the public interest to be granted a Corps permit. The Corps
may ultimately make a determination to permit or deny the above
project, or permit or deny modified versions of the above project.
FOR FURTHER INFORMATION CONTACT: Questions about the proposed action or
the scoping of the Draft EIS can be answered by Michael Langley, Corps
Senior Project Manager, at (602) 230-6953. Comments regarding scoping
of the Draft EIS shall be addressed to: U.S. Army Corps of Engineers,
Los Angeles District, Arizona Regulatory Branch, ATTN: SPL-2011-01005-
MWL, 3636 North Central Avenue, Suite 900, Phoenix, Arizona 85012-1939,
or [email protected]. Comments letters sent via
electronic mail shall include the commenter's physical address and the
project title ``Ray Mine Tailings Storage Facility Project'' shall be
included in the subject line.
SUPPLEMENTARY INFORMATION:
1. Project Site and Background Information: The 2,350-acre project
site is located in eastern Pinal County, Arizona approximately four
miles south of the Ray Mine Complex, south of the Gila River, on lands
owned by Asarco, on lands owned and managed by the Bureau of Land
Management, and on lands currently owned and managed by the Arizona
State Land Department that Asarco is seeking to acquire. The project
pipelines would run along the Florence-Kelvin Highway from the
thickeners at the Ray Mine to the proposed TSF.
Asarco is the owner and operator of the Ray Mine Complex in Pinal
County, Arizona, an open-pit copper mine with an on-site concentrator
and leaching facilities. Asarco also owns associated concentrating and
smelting facilities located in Hayden, Arizona, approximately 17 miles
southeast of the mine. The Ray Mine was originally founded in 1882 as a
silver mine with the mining of copper beginning somewhat later.
A Clean Water Act Section 404 permit was issued for construction of
the Elder Gulch tailings impoundment at Ray Mine in 1991; modifications
to that permit were issued in 1996, 1997, and 1998 for ongoing mining
and mitigation activities. In May 2011, a new Section 404 permit was
obtained that authorizes continued operation and expansion of the Elder
Gulch tailings facility, construction of a stormwater diversion system
upgradient of the tailings facility, and continued placement of rock
into rock deposition areas previously authorized in the 1991 Section
404 permit (as modified by the subsequent amendments). Prior to the May
2011 Section 404 permit that authorized expansion of the Elder Gulch
impoundment, that facility was expected to reach capacity in
approximately 2013. Raising the crest elevation of the impoundment to
the 2,590 ft level as authorized by the May 2011 Section 404 permit,
will allow the existing Elder Gulch tailings impoundment to be used for
an anticipated five to seven additional years. The Ray Mine has proven
ore reserves that will allow mining to continue well past that
timeframe, and additional expansions of the Elder Gulch facility are
not technically and environmentally feasible.
2. Proposed Action: Asarco is proposing to construct, operate, and
close a tailings storage facility to support continuing copper mining
activities at the Ray Mine Complex. The facility would accommodate
tailings that would be collected at the mine, transported via a
tailings delivery pipeline, and deposited in slurry form at a discharge
point east of Ripsey Wash, an ephemeral wash that is a tributary to the
Gila River. The facility footprint is estimated at 2,129 acres and
currently has an elevational range of approximately 1,800 to 2,400 feet
above mean sea level. The facility is designed for an overall storage
capacity of 751.3 million tons of tailings and embankment materials
with a final crest elevation of 2,440 feet. The proposed facility would
be built with centerline and upstream construction methods.
A diversion embankment, stormwater detention pond, and channel
would be constructed at the upgradient end of the facility to divert
flows around the facility to the west to Zelleweger Wash. The diversion
embankment and stormwater detention pond are designed to handle the
500-year, 24-hour storm event. Water from this impoundment would be
pumped and piped to the western diversion channel for conveyance to
Zelleweger Wash. A second diversion channel would be constructed along
the east side of the facility to drain stormwater runoff from
upgradient of the facility to an unnamed tributary wash to the Gila
River.
The starter tailings embankment would be constructed at the
downgradient end of the facility with a 50-foot-wide berm. Cyclone
sands would be used to construct the phased embankments. The ultimate
embankment would be constructed to an elevation of 2,440 feet above
mean sea level with a tailings deposition elevation just below this
elevation.
Some seepage from the tailings impoundment is expected and would
infiltrate the alluvial deposits located within Ripsey Wash and its
tributaries. Therefore, a seepage collection trench would be
constructed within Ripsey Wash downstream of the impoundment to contain
the seepage, and a second seepage collection trench will be constructed
in a drainage on the east side of the facility. The seepage collection
trench will be constructed with a geomembrane liner anchored to bedrock
and granular drain rock along the upstream face of the trench to
intercept seepage from the tailings facility. A series of riser pipes
will be installed within the trench and fitted with submersible pumps
to pump collected seepage to the associated reclaimed water ponds.
Asarco is proposing to construct and operate tailings delivery and
reclaimed water pipelines as part of the project. The tailings
generated from the mill at the Ray Mine would be pumped in slurry form
through the tailings delivery pipeline to the proposed facility
impoundment area for deposition and a reclaimed water pipeline would be
used to pipe reclaimed water back to the Ray Mine for reuse. The
pipelines would be constructed along the Florence-Kelvin Highway and
connect to the proposed tailings deposition point and reclaimed water
ponds located at the proposed facility. The pipelines would be
constructed along the existing alignment of the Florence-Kelvin
Highway. To address the unlikely event of a pipeline failure, a drain
down pond is planned along the pipeline route north of the Gila River
for containment of tailings and/or reclaimed water. A pipeline bridge
would be constructed at the point
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where the pipeline route crosses the Gila River.
A 2.2-mile segment of the Florence-Kelvin Highway, a Pinal County-
maintained roadway, would require realignment as a result of
constructing the facility. A 2.1-mile section of the road would be
relocated north of its current alignment.
The proposed facility would require the relocation of the San
Carlos Irrigation Project power line which currently passes though the
northern portion of the facility footprint. An approximately 2.3-mile
segment of the power line will be moved north of the TSF and rerouted
around the western portion of the project area, approximately following
the proposed and existing alignment of the Florence-Kelvin Highway. The
planned rerouted power line corridor is approximately 3.2 miles in
length.
3. Issues: There are several potential environmental issues that
will be addressed in the Draft EIS. Additional issues may be identified
during the scoping process. Issues initially identified for evaluation
in the Draft EIS include:
1. Visual/aesthetics impacts from landform alterations,
2. air quality impacts from construction and operation of the
facility,
3. cultural resources (prehistoric and historic resources),
4. surface water hydrology and quality,
5. groundwater hydrology and quality,
6. potential land use incompatibility,
7. noise impacts from construction and operation,
8. Impacts to recreation resources,
9. socioeconomic effects,
10. soils and geotechnical stability issues,
11. transportation network impacts, and
12. biological impacts (vegetation, wildlife, waters of the U.S.).
4. Alternatives: Several alternatives to the proposed action are
being considered in the Draft EIS. The Draft EIS will include a co-
equal level of analysis of the No-Action and project alternatives
considered. Currently, there are five potential off-site project
alternatives being considered along with the proposed action and two
variations of the proposed action. These alternatives will be further
formulated and developed during the scoping process. Additional
alternatives may be developed during scoping that will also be
considered in the Draft EIS.
5. Scoping: The Corps will conduct two public scoping meetings for
the proposed Ray Mine Tailings Storage Facility Project Draft EIS to
receive public comment and to assess public concerns regarding the
appropriate scope and preparation of the Draft EIS. Participation in
the public meetings by federal, state, local, and tribal agencies and
other interested organizations is encouraged. The first meeting will be
held on September 24, 2013 beginning at 6:00 p.m. (Arizona Time Zone)
at Kearny Junior-Senior High School, 701 Arizona 177, Kearny, Arizona
85137. The second meeting will be held on September 25, 2013 beginning
at 6:00 p.m. (Arizona Time Zone) at Apache Junction High School, 2525
South Ironwood Drive, Apache Junction, Arizona 85120. Comments on the
proposed action, alternatives, or any additional concerns should be
submitted in writing. Written and electronic comment letters will be
accepted through October 28, 2013.
The Corps also anticipates formally consulting with the U.S. Fish
and Wildlife Service under Section 7 of the Endangered Species Act and
with the State Historic Preservation Officer and appropriate Tribal
Historic Preservation Officers under Section 106 of the National
Historic Preservation Act.
6. Availability of the Draft EIS: The Draft EIS is expected to be
published and circulated in the fourth quarter of 2014, and a public
meeting will be held after its publication.
Dated: August 12, 2013.
David J. Castanon,
Division Chief, Los Angeles District, U.S. Army Corps of Engineers.
[FR Doc. 2013-20733 Filed 8-23-13; 8:45 am]
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