[Federal Register Volume 59, Number 164 (Thursday, August 25, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-20858]
[[Page Unknown]]
[Federal Register: August 25, 1994]
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DEPARTMENT OF THE INTERIOR
Bureau of Mines
Santa Cruz In Situ Copper Mining Research Project; Draft
Environmental Assessment; Public Meeting
AGENCY: Bureau of Mines, Interior.
ACTION: Notice of availability of draft environmental assessment (EA)
prepared for the Santa Cruz In Situ Copper Mining Research Project and
notice of public meeting.
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SUMMARY: In accordance with section 102 (2) (C) of the National
Environmental Policy Act (NEPA), a draft EA has been prepared for the
Santa Cruz In Situ Copper Mining Research Project and is currently
available for public review and comment. The proposed action is the in
situ mining of copper from a copper oxide zone using a pattern of
injection and recovery test wells, and fabrication and operation of a
pilot-scale solvent extraction-electrowinning (SX-EW) facility to
remove dissolved copper from solution. The project site is located
approximately 7 miles west of the city of Casa Grande, Arizona. A
public meeting to receive comments on the draft EA is scheduled.
Individual copies of the draft EA may be requested directly from the
Bureau or viewed at the Casa Grande city library.
DATES: The public meeting will be held on September 14, 1994, beginning
at 7 p.m. MST. The meeting room will be open at 6:30 p.m. for review of
displays and informal discussions with project personnel. Comments on
the draft EA must be received no later than September 26, 1994.
ADDRESSES: The public meeting will be held at the Holiday Inn, 777
North Pinal Avenue, Casa Grande, AZ.
Comments on the draft EA should be sent to: Daniel J. Millenacker,
U.S. Bureau of Mines, Twin Cities Research Center, 5629 Minnehaha
Avenue South, Minneapolis, Minnesota 55417-3099.
FOR FURTHER INFORMATION CONTACT: For information or to obtain a copy of
the draft EA, contact Daniel J. Millenacker at the address identified
above or by phone at (612) 725-4588.
SUPPLEMENTARY INFORMATION: In situ copper mining involves the injection
of a dilute sulfuric acid solution through a well or wells completed
into an otherwise undisturbed ore zone; selective dissolution of copper
as the solution moves through and contacts copper oxide mineralization
located along natural fractures; collection of copper-bearing solution
by recovery wells; removal of the dissolved copper from collected
solution using a conventional SX-EW plant located on the surface;
rejuvenation of solution to its original strength; and solution
reinjection back into the ore zone to repeat the cycle. The project
well field will consist of one injection test well in the center of a
square measuring 127 ft to a side, and a recovery test well located at
each of the four corners of the square. This arrangement is referred to
as a ``five-spot'' well pattern. Injection of solution will occur at a
rate of about 10 to 50 gal/min. The total area to be occupied by the
various components of the project (including injection and recovery
test wells, ground water monitor wells, and SX-EW facility) is 8 1/2-
acres.
The research project is a cooperative effort of the Bureau of Mines
and the Santa Cruz Joint Venture (a joint venture formed between ASARCO
Santa Cruz, Inc., and Freeport Copper Company). The goal of the
research project is to determine the technical, economic, and
environmental feasibility of in situ mining of copper oxide minerals.
The research plan calls for in situ mining to continue until sufficient
data are collected to evaluate the mining technique. This time period
is presently estimated to require 18 months to complete, but it may
extend for up to 4 years. In addition to an environmental review
performed under NEPA, this project is subject to Federal, State, and
local environmental permitting requirements.
Dated: August 18, 1994.
Lewis V. Wade,
Research Director, Twin Cities Research Center.
[FR Doc. 94-20858 Filed 8-24-94; 8:45 am]
BILLING CODE 4310-53-P
