[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

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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]
BILLING CODE 3720-58-P