Thompson Creek Supplemental Plan of Operation Challis National Forest, Custer County, Idaho

DEPARTMENT OF AGRICULTURE

Thompson Creek Supplemental Plan of Operation Challis National

Forest, Custer County, Idaho

AGENCY: Forest Service, USDA.

ACTION: Notice of intent to prepare supplemental environmental impact

statement.

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SUMMARY: The USDA, Forest Service, will prepare a supplement to the

October 1980, Environmental Impact Statement (EIS) for the Cyprus

Thompson Creek Mine (CTC). The Supplement will disclose the

environmental effects of a proposal submitted by Thompson Creek Mining

Company (TCMC) to prevent, control and treat acid rock drainage (ARD)

at the Thompson Creek Mine. The potential for acid rock drainage was

evaluated in the 1980 EIS, however, the predictive modeling program did

not project that acid generation would be sufficient to cause ARD. The

occurrence of ARD is a new circumstance, relevant to environmental

concerns and bearing on the impacts of the project, therefore, the 1980

EIS will be supplemented to disclose the effects of these new

circumstances. The proposal, as submitted by CTC, identifies

modifications to the operating plan which would eliminate or control

acid rock drainage. The modifications to the plan would: (1) Identify

and isolate waste rock that has the potential for ARD, (2) limit

infiltration and migration [[Page 7749]] of acid drainage within the

identified waste rock and (3) modify the tailings disposal process by

adding a pyrite reduction system to separate the residual pyrite from

the tailings. The pyrite concentrate would be disposed of in a

subaqueous environment where oxidation and acid generation would be

prevented. The proposal also discusses measures to be taken should

mining operations terminate prior to the construction of the pyrite

reduction system outlined above. In that circumstance, TCMC proposes to

place a cap of inert material on the tailings embankment and

impoundment to alleviate acid generation.

There are approximately 525 acres of patented land in the project

area, including the open pit. The remainder, approximately 2,500 acres,

is land administered by the Challis National Forest or the Salmon

District of the Bureau of Land Management. The mine is located in

Custer County, five miles north of the Salmon River and 30 miles

southwest of Challis, Idaho.

The proposal to develop and implement measures to prevent, control

and treat ARD represents both connected or cumulative actions as

defined by the Council on Environmental Quality (40 CFR 1508.25). The

purpose of the proposal is to continue the development of a mineral

resource while minimizing or preventing adverse effects resulting from

ARD that were not predicted in the 1980 Thompson Creek EIS or approved

Plan of Operations. Forest Service policy is to facilitate the orderly

exploration, development and production of mineral resources within the

National Forest System on lands open to these activities. At the same

time, the Forest Service is charged to ensure that these activities are

conducted in an environmentally sound manner, and that once completed,

reclamation of the land to a stable and usable condition is

accomplished.

This supplement to the 1980 EIS will tier to the Challis National

Forest Land and Resource Management Plan (Forest Plan) and Final EIS

(June 1987) which provide overall guidance of all land management

activities on the Challis National Forest, including mineral

exploration and development. This document also tiers to the 1980

Environmental Impact Statement for the Thompson Creek Molybdenum

Project.

DATES: Written comments and suggestions must be submitted on or before

March 13, 1995.

ADDRESSES AND FURTHER INFORMATION: Submit written comments and

suggestions on the proposed activities to Liz McFarland, Project

Coordinator, Salmon and Challis National Forests, Headquarters

Building, P.O. Box 729, Salmon, Idaho, 83467, Phone (208) 756-5139. To

be placed on the project mailing list or for additional information,

contact the Project Coordinator identified above.

SUPPLEMENTARY INFORMATION: The Thompson Creek Mining Company submitted

a Supplemental Plan of Operation for the Thompson Creek Molybdenum Mine

to the Challis National Forest and the Salmon District of the Bureau of

Land Management in February 1993. The Supplemental Plan was revised in

February 1994. The Supplemental Plan was based on a sampling program

initiated in 1990 to characterize ARD. The plan, as proposed by TCMC is

summarized as follows:

1. Minimize the amount of water and air coming into contact with

sulfide minerals by encapsulating waste rock (determined to have the

potential to generate ARD) with compacted volcanic material within the

existing waste dumps. Final reclamation of the waste dumps would

consist of shaping and covering surfaces with materials designed to

prevent upward diffusion of acidity, limit the infiltration of water,

protect cover materials from freeze-thaw damage and support growth of a

vegetative cover.

2. The existing milling process would be modified to remove a

portion of the pyrite sufficient to produce an inert tailings. The

pyrite removed would be disposed of in areas of the impoundment which

will be saturated with water in order to limit exposure to oxygen. The

inert tailings produced would be placed on the embankment, paddock and

beach portion of the tailings facility. As proposed, this would result

in approximately 140 feet of inert tailings, by close of mine. At final

reclamation, the interior of the impoundment area would be regraded

using inert material so that surface drainage is directed toward the

west side of the embankment. This would produce a free water pond near

the west side of the embankment and a minimum 10 foot layer of inert

material over the interior of the impoundment. The remainder of the

impoundment would be covered by 140 feet of inert tails or a low

permeability soil cap or a layer of inert fill 15 to 30 feet thick.

3. Hydrologic investigations indicate that the pit would fill at

least partially with water when mining ends. Hydrogeologic studies and

geochemical analyses would be conducted prior to mine closure and

appropriate measures to preserve in-pit water quality would be

developed.

The Challis Forest Plan provides guidance for management activities

within the potentially affected area through its goals, objectives,

standards and guidelines, and management area direction. The proposal

would occur within Management Areas 8 and 9. Management in these areas

emphasize enhancement of fish and wildlife habitat, range

administration, maintenance of water quality, timber production and

dispersed recreation. It recognizes the potential for high-value,

locatable mineral occurrence and probable development. It directs that

exploration, location, leasing and development of energy and non-energy

minerals resources be coordinated with other resources.

The decision to be made is what should be done in relation to the

proposal submitted by TCMC: (a) Approve the project as proposed, (b)

approve the project with mitigation measures to address the issues, (c)

deny approval of the proposal. Under the United States mining Laws of

May 10, 1872, as amended (30 U.S.C. 22), United States citizens and

corporations have the right to search for and develop minerals upon

public lands, including National Forest Systems lands, open to mineral

entry. Forest Service regulations (36 CFR 228, Subpart A) require that

the agency work with mineral operators to minimize or eliminate adverse

environmental impacts from mineral activities on National Forest System

lands.

The Supplement will analyze the direct, indirect, and cumulative

environmental effects of the alternatives. Past, present, and projected

activities on private Bureau of Land Management and National Forest

lands will be considered. The Supplement will disclose the analysis of

site-specific mitigation measures and their effectiveness.

Public participation is an important part of the analysis process

(40 CFR 1501.7). Scoping activities, to date, have included the

following: Letter and scoping document, dated 2/15/94, to interested

individuals, groups and organizations; press release and legal

narrative in the ``Challis Messenger'' and the Salmon ``Recorder-

Herald,'' 2/17/94. The public is encouraged to visit with Forest

Service officials at any time during the analysis and prior to the

decision. In addition, the Forest Service is seeking information,

comments, and assistance from federal, state, and local agencies and

other individuals or organizations who may be interested in or affected

by the proposed action. No [[Page 7750]] additional public meetings are

scheduled at this time.

Comments from the public and other agencies will be used to prepare

the Draft Supplemental EIS. The scoping process to date has identified

the following preliminary issues:

1. What is the potential for development of acid mine drainage and

mobilization of heavy metals from geologic materials exposed by mining

activities?

2. How would existing mine facilities and activities be changed to

prevent, control or treat ARD? What are the long term maintenance

requirements of these facilities along with their predicted long-term

viability and stability and how would bonding reflect these changes?

3. What is the potential for adverse impacts to water quality

downstream of project facilities due to ARD and how would water quality

be maintained and beneficial uses protected?

4. Would fish and their habitat be affected by ARD discharges into

area streams? What are the potential impacts to fish species listed as

threatened or endangered under the Endangered Species Act?

5. Would water monitoring be adequate to detect and allow for the

correction of any water quality problems resulting from the proposed

action?

This list may be verified, expanded, or modified based on

additional scoping for this proposal.

In order to implement the project, the proponent, TCMC, must obtain

approval or consultation of their proposed modification from other

regulatory agencies including the Environmental Protection Agency

(EPA), National Marine Fisheries Service (NMFS), U.S. Fish and Wildlife

Service (USFWS), Idaho Department of Lands (IDL), Idaho Department of

Health and Welfare (IDHW) and the Idaho Department of Water Resources

(IDWR). Implementation may take place through the selection of an

alternative from the Supplemental EIS.

The Challis National Forest is the lead agency in this

environmental analysis and Supplemental EIS. The Salmon District office

of the Bureau of Land Management is a cooperating agency.

The Draft Supplemental EIS is expected to be filed with the

Environmental Protection Agency (EPA) and available for public review

in late July 1995. At that time, the EPA will publish a Notice of

Availability of the Draft Supplemental EIS in the Federal Register. The

comment period on the Draft Supplemental EIS will be 45 days from the

date the EPA's notice of availability appears in the Federal Register.

It is very important that those interested in this proposal participate

at that time. To be most helpful, comments on the Draft EIS should be

as specific as possible. The Final Supplemental EIS is scheduled to be

completed by December, 1995.

The Forest Service believes, at this stage, it is important to give

reviewers notice of several court rulings related to public

participation in the environmental review process. First, reviewers of

draft environmental impact statements must structure their

participation in the environmental review of the proposal so that it is

meaningful and alerts an agency to the reviewer's position and

contentions. Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519,

553 (1978). Also, environmental objections that could be raised at the

draft environmental impact statement stage, but that are not raised

until after completion of the final environmental impact statement, may

be waived or dismissed by the courts. City of Angoon v. Hodel, 803 F.2d

1016, 1022 (9th Cir. 1986) and Wisconsin Heritages, Ind. v. Harris, 490

F. Supp. 1334, 1338 (E.D. Wis. 1980). Because of these court rulings,

it is very important that those interested in this proposed action

participate by the close of the 45-day comment period so that

substantive comments and objections are made available to the Forest

Service at a time when it can meaningfully consider them and respond to

them in the final environmental impact statement.

To assist the Forest Service in identifying and considering issues

and concerns on the proposed action, comments should be as specific as

possible. Reviewers may wish to refer to the Council on Environmental

Quality Regulations for implementing the procedural provisions of the

National Environmental Policy Act at 40 CFR 1503.3 in addressing these

points.

I am the responsible official for this environmental impact

statement. My address is Salmon and Challis National Forests, P.O. Box

729, Salmon, Idaho 83467.

Dated: February 3, 1995.

Charles C. Wildes,

Forest Supervisor, Challis National Forest.

[FR Doc. 95-3217 Filed 2-8-95; 8:45 am]

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