Intent To Prepare a Draft Environmental Impact Statement (DEIS) for the Proposed North Expansion of Kennecott Copper's Tailings Impoundment in Salt Lake County, UT

DEPARTMENT OF DEFENSE

Army Corps of Engineers

Intent To Prepare a Draft Environmental Impact Statement (DEIS)

for the Proposed North Expansion of Kennecott Copper's Tailings

Impoundment in Salt Lake County, UT

AGENCY: U.S. Army Corps of Engineers, DoD.

ACTION: Notice of Intent.

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SUMMARY: Kennecott Copper proposes to expand their current tailings

impoundment by an additional 3,500 acres. The present tailings

impoundment is reaching its storage capacity. Kennecott projects the

need to store an additional 1.9 billion tons of tailings in order for

operation and production to continue throughout the life of the mine.

In addition, Kennecott has identified the need for a seismic upgrade of

the existing impoundment. The intended location of the expanded

facility and its design is projected to meet this need. Construction of

the north expansion will require a Department of the Army permit

pursuant to Section 404 of the Clean Water Act. The Corps of Engineers,

as the lead Federal agency for this project, has determined that an

Environmental Impact Statement will be required prior to making a

permit decision.

FOR FURTHER INFORMATION CONTACT: Mr. Michael Schwinn, Project Manager,

U.S. Army Corps of Engineers, Sacramento District, Utah Field Office,

1403 South 600 West, Suite A, Bountiful, Utah 84010, Telephone (801)

295-8380.

SUPPLEMENTARY INFORMATION: Kennecott Copper owns and operates the

Bingham Canyon Mine 30 miles southwest of Salt Lake City, Utah within

the Oquirrh Mountains. Copper ore is mined from an open pit mine and

processed at the concentrator, smelter and refinery facilities. Annual

production of copper from the facility is over 250,000 tons annually,

Tailings, the end-product of the process, are disposed in a slurry to

an existing impoundment.

The existing impoundment's footprint covers approximately 5,700

acres and contains 1.7 billion tons of tailings. The current

impoundment is 190 feet high. It has the capacity for an additional 0.3

to 0.4 billion tons of tailings which will raise its height to 250

feet. Its capacity is projected to be reached by 1998. However, the

expected life of the mine is estimated at an additional 30 years with a

total production of 1.9 billion more tons of tailings.

Construction of the North Expansion will occur in two phases. The

Phase 1 design will provide for 1.1 billion tons of tailings storage.

(An additional 0.3 to 0.4 billion tons of tailings will be deposited

into the existing impoundment during the remaining years of service.)

Related project elements for Phase 1 include construction of the North

Expansion berm, expanded dewatering of select reaches of the existing

impoundment, and modification of the process water system, all designed

to enhance the seismic stability of the existing impoundment. Phase 1

is expected to run from year 1999 to 2018.

Phase 2 construction of the North Expansion will allow storage of

an additional 0.4 to 0.5 billion tons of tailings, resulting in a final

impoundment height of 250 feet by the year 2027.

Construction of the North Expansion will require a new pipeline

bridge and modification of the tailings distribution system. It will

also involve relocating utility lines, powerlines, the C-7 ditch, the

Union Pacific Railroad main lines, the construction of a new bridge for

Highway 202 over the relocated railroad lines and the modification of

Interstate 80 on and off ramps.

In addition to the proposed North Expansion, other alternatives

have tentatively been identified. These include both onsite and offsite

alternatives. The onsite alternatives range from the proposed North

Expansion to the continued raising and impounding of tailings within

the existing impoundment. Offsite alternatives would involve separate

sites capable of meeting the tailings storage capacity needs. Five have

been identified: Barneys Canyon, Coon Canyon, Dry Fork/Carr Fork,

Tooele/Carr Fork and Stockton. All sites are located in the Oquirrh

Mountains and within Kennecott Copper's mine properties. Alternatives

and their practicability will be analyzed by the Corps of Engineers

pursuant to the 404(b)(1) Guidelines contained in 40 CFR Part 230.

Public Scoping Meeting

A public scoping meeting will be held to help identify significant

issues and alternatives for inclusion in the DEIS. Potentially

significant issues to be analyzed in the DEIS include wetland impacts,

impacts to surface and ground water, both in terms of quantity and

quality; public safety, air quality, fish and wildlife impacts,

transportation and traffic. A public scoping meeting will be held at

the following time and location: 6 p.m., Wednesday, September 19, 1994:

Main Auditorium, Utah Department of Natural Resources, 1636 West North

Temple, Salt Lake City, Utah.

Federal, state and local agencies as well as other interested

parties are encouraged to attend the scoping meeting. In addition,

written comments addressing relevant issues to be considered in the

DEIS as per this NOI may be sent to Mr. Schwinn at the above address.

Comments in response to this NOI will be received until the date of the

scoping meeting.

Dated: August 12, 1994.

Michael P. Stuhr,

Lieutenant Colonel, Corps of Engineers, Deputy District Engineer.

[FR Doc. 94-20406 Filed 8-18-94; 8:45 am]

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