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6223424 DRAFT ENVIRONMENTAL IMPACT

ESOdesm

STATEMENT



Stillwater Mine Revised Waste Management Plan
and Hertzler Tailings Impoundment




ATE DOCUMENTS COLLECTION

OD 1 2 2001

MONTANA STATE LIBRARY

1515 E. 6th AVE.
HEUNA, MONTANA 59620




Prepared by

Montana Department of Environmental Quality

and

U.S.D.A. Forest Service




March 1998



MONTANA STATE LIBRARY



3 0864 0015 6362 9



DATE DUE




Custer National Forest

HC 49, Box 3420

Red Lodge, MT 59068



Montana Department of
Environmental Quality
P.O. Box 200901
Helena, MT 59620-0901




March 4, 1998

Re: Release and review of draft Environmental Impact Statement for the Stillwater Mine
Revised Waste Management Plan and Hertzler Tailings Impoundment

Dear Reader:

The Stillwater Mining Company (SMC) has proposed a revision to its operating permit #00 1 1 8 and
approved plan of operations for the Stillwater Mine located outside Nye, Montana, in Stillwater County.
The Custer National Forest (CNF) and the Department of Environmental Quality (DEQ) have released
the draft Environmental Impact Statement (EIS) for the Stillwater Mine Revised Waste Management Plan
and Hertzler Tailings Impoundment. A copy of this document is being sent to you for your review. This
EIS covers the proposed revision and revisions to the Stillwater Mine's air quality permit as well as the
Forest Service's biological assessement and evaluation for the proposed action. We recommend you
begin by reading the summary of the EIS and then proceeding to chapters in the EIS where the more
detailed information can be found. Chapters 1 and 2 contain the bulk of the information including a
summary of the impacts that are described in detail in Chapter 4. The appendices contain more technical
information. More information regarding the content of each chapter can be found in the document
Preface.

The public comment period will run for 60 days beginning March 20, 1998, and ending May 19, 1998.
During that time you are welcome to submit written comments to the agencies at the addresses listed
above. In addition to written comments, verbal comments will be recorded at the hearing to be held at
the Absarokee Elementary School gym (the old high school) at 7 p.m. on Tuesday, April 28, 1998. An
open house will be held at 6 p.m before the hearing where you may ask technical and procedural
questions of agency personnel.

The agencies are required to respond in the final EIS to all substantive comments on the draft EIS. The
comment period mentioned above provides you, the public, with an opportunity to make an impact on the
content of the document and, therefore, potentially affect the decision that will be made after the final EIS
is released. We ask that your comments relate directly to the EIS, that you are as specific as possible,
and that you cite the location(s) in the document on which you are commenting. While public opinions

1



for or against the proposed action are of interest, they are often not useful for modifying an EIS and they
seldom have any bearing on the criteria the agencies must use to make decisions regarding proposals.

If you have any questions, please contact the agency staff listed below:



Pat Pierson, Project Coordinator
Beartooth Ranger District
HC49, Box 3420
Red Lodge, NfF 59068
(406)446-2103



Kathleen Johnson, Project Coordinator
Montana Department of Environmental Quality
P.O. Box 200901
Helena, MT 59620-0901
(406)444-1760



Sincerely,



liy^^^^



J- lji/>M^f^^



Nancy Curriden, Forest Supervisor
Custer National Forest



Sincerely,



Mark Simonich, Director

Montana Department of Environmental Quality



Draft Environmental Impact Statement



Stillwater Mine Revised Waste Management Plan
and Hertzler Tailings Impoundment



March 1998



USDA Forest Service Montana Department of

Custer National Forest Environmental Quality



Nancy T. Curriden, Forest Supervisor Marx Simonich, Director



COVER SHEET



Type of Statement:
Proposed Action:

Lead Agencies:
Abstract:



Draft Environmental Impact Statement

Revision of Stillwater Mining Company's Existing Waste
Management Plan and the Construction and Operation of the
Hertzler Tailings Impoundment

Montana Department of Environmental Quality
USDA Forest Service, Custer National Forest

The Stillwater Mine Revised Waste Management Plan and Hertzler
Tailings Impoundment Draft Environmental Impact Statement
describes the land, people, and resources potentially affected by the
proposed revision. The major federal and state action consists of
the approval of all necessary permits to construct and operate the
revised waste management plan. The proposed project would
consist of four primary aspects: the construction and operation of a
new tailings impoundment at the former Hertzler Ranch, the
construction and operation of pipelines to transport tailings slurry
and water between the mine and the Hertzler tailings
impoundment, the construction and operation of a new waste rock
storage facility, expansion of the Land Application Disposal
system, and the removal of the limitation on daily production
(currently 2,000 tons per day). The No Action Alternative,
Proposed Action Alternative, and two additional action alternatives
are analyzed in detail.



For Further Information, Please Contact:

Pat Pierson

Custer National Forest

Red Lodge Ranger District

HC 49, Box 3420

Red Lodge, Montana 59068

(406)446-2103



Kathleen Johnson

Montana Department of Environmental Quality

Permitting and Compliance Division

Box 200901

Helena Montana 59620-0901

(406)444-1760/4323



Preface



An Environmental Impact Statement (EIS) is not usually read like a book,
from chapter one to the end. The best way to go about reading an EIS
depends on your interests. You may be more interested in effects, whereas
others might have more interest in the details of the proposed plan or be more
concerned about what opportunities were made available for the public to be
involved in the environmental assessment process. Many readers probably just
want to know what is being proposed and how it will affect them.

This document follows the format established in the Montana Environmental
Policy Act's regulations (ARM 17.4.601 to 17.4.636) and the National
Environmental Policy Act's regulations (40 CFR 1 500 to 1 508). The following
paragraphs outline information contained in the chapters and appendices so
readers may find the parts of interest without having to read the entire document.

>* Summary: contains a short, simple discussion to provide the reader and the
decision makers with a sketch of the more important aspects of the EIS.
The reader can obtain additional, more-detailed information from the actual
text of the EIS.

>» Chapter 1 —Purpose and Need: describes the proposed action, purpose
of and need for the proposed action, history of the Stillwater Mine,
decisions to be made by the agencies, agencies' roles and responsibilities,
MEPA/NEPA process, and other permits required.

>* Chapter 2 —Public Participation, Issue Identification, and Alternative
Development: describes SMC's Proposed Action, the significant issues
associated with the Proposed Action, and alternatives to that action,
including the no action alternative. Action alternatives that at least partially
meet the purpose and need were developed by the agencies in response to
one or more of the key issues. Alternatives considered but dropped from
detailed consideration are identified along with the rationale for not
including them in the analysis. Reasonably foreseeable activities near the
proposed project are identified. This chapter also provides a comparative
analysis of the environmental effects of the primary alternatives to provide
a clear basis of choice among options for the decision maker and public.
The lead agencies' preferred alternative is identified.

>- Chapter 3 —Affected Environment: describes the present condition of the
environment that would be affected by the proposed action and alternatives.



P-1



Preface



>■ Chapter 4 —Environmental Consequences: describes the probable direct,
indirect, and cumulative effects to the human environment that would result
from implementing the Proposed Action or alternatives. The discussion
also addresses short-term uses versus long-term productivity, unavoidable
impacts, and irreversible or irretrievable impacts. Resources without
significant effects or issues are not discussed.

>" Chapter 5 — Consultation with Others: identifies the agencies, companies,
and organizations consulted as well as the cooperating agencies.

>- Chapter 6 —Preparers and Contributors: identifies the people involved in
the research, writing, and internal review of the draft EIS.

>" Chapter 7 —Distribution and Review of the Draft EIS: lists the agencies,
organizations, and individuals who received a copy of the draft EIS.

>* Chapter 8 —Glossary: describes the technical terms, abbreviations, and
acronyms used in the draft EIS.

>* Chapter 9 —References Cited: lists the references cited in the draft EIS.

>* Index: contains cross references and identifies the pages where key topics
can be found.



P-2



Preface



Acronyms and Abbreviations used in this EIS



ABC

ADT

APE

AQG

AUM

BACT

CEQ

CFR

cfs

CNF

COE

CWA

DEQ

DHES

DSL

EIS

EPA

ESA

gpm

HOPE

KOP

LAD

LOS

MDFWP

MEPA

MPDES

NAAQS

NEPA

NHPA

NOAA

NRHP

PM,o

ppm

PSD

SHPO

TDS

tpd

tpy

USFWS

USGS

VQO



Anoxic Biotreatment Cell

Average Daily Traffic

Area of Potential Effect

Ambient Air Quality Guidelines

Animal Unit Month

Best Available Control Technology

Council on Environmental Quality

Code of Federal Regulations

Cubic Feet per Second

Custer National Forest

U.S. Army Corps of Engineers

Clean Water Act

Montana Department of Environmental Quality

Montana Department of Health and Environmental

Services

Montana Department of State Lands

Environmental Impact Statement

U.S. Environmental Protection Agency

Endangered Species Act

Gallons per Minute

High-density Polyethelene

Key Observation Point

Land Application Disposal

Level of Service

Montana Department of Fish. Wildlife, and Parks

Montana Environmental Policy Act

Montana Pollutant Discharge Elimination System

National Ambient Air Quality Standards

National Environmental Policy Act

National Historic Preservation Act

National Oceanic and Atmospheric Administration

National Register of Historic Places

Respirable Particulate Matter less than 10 microns in

aerodynamic diameter

Parts per Million

Prevention of Significant Deterioration

State Historic Preservation Office

Total Dissolved Solids

tons per day

tons per year

U.S. Fish and Wildlife Service

U.S. Geological Survey

Visual Quality Objective



P-3



Summary — Stillwater Mine Revised
Waste Management Plan Draft
Environmental Impact Statement



Introduction

The Montana Department of Environmental Quality (DEQ) and the USDA
Forest Service, Custer National Forest (CNF) served as joint lead agencies for
the preparation of an Environmental Impact Statement (EIS) in response to a
proposal filed by Stillwater Mining Company to amend its operating permit
(#001 18). This Executive Summary summarizes the draft EIS.

The proposed amendment, which SMC submitted on April 29, 1996, requests
authorization to make specific changes to SMC's mine waste management
operation at the Stillwater Mine. The specific changes include;

>- constructing and operating a new tailings impoundment on the Hertzler
Ranch, which is about 7.8 miles northeast of the mine site;

>* installing a system of pipelines along Stillwater County roads 419 and 420
connecting the new tailings impoundment to the mine's mill and tailing
reclaim circuit;

>* expanding the waste rock storage areas on the east side of the Stillwater
River across from the mine;

>* relocating the Land Application Disposal system (LAD) from its current
location on the east side of the Stillwater River near the mine site to both
the Stratton Ranch (1.5 miles northeast of the mine along Stillwater County
Road 419) and the Hertzler Ranch; and

5* removing the 2,000 tons per day (tpd) restriction on processing ore.

(Having no restrictions on processing allows SMC to expand its processing
of ore to match the capabilities of mining and milling equipment. The
average rate is expected to be around 3,000 tpd, but it may peak as high as
5,000 tpd occasionally.)

These facilities would allow SMC to continue mining platinum group metals for
about 30 more years. The Proposed Action would involve private lands owned
by SMC, public rights-of-way administered by Stillwater County, and National
Forest System lands administered by CNF. The sites are located in Stillwater
County, approximately 35 miles southwest of Columbus, Montana (Figure S-1).



S-1



Summary




Scxft« >n U/tos



Figure S-1 Location of Stillwater Mine and Hertzler Ranch



This EIS was prepared to analyze and document the potential environmental
consequences that may result from implementing the Proposed action or one of
the alternatives. The EIS was prepared in accordance with the Montana
Environmental Policy Act (MEPA) and the National Environmental Policy Act
(NEPA) and the respective laws and regulations of the State of Montana and the
USDA Forest Service.

MEPA contains the procedures that govern the decision-making process on state
and private lands in Montana. If any action taken by a state agency may
"significantly affect the quality of the human environment'", this law requires the
preparation of an EIS. NEPA governs the decision-making process for federal
agencies. Some of the affected lands for this project are administered by the
CNF and the Forest Supervisor will use the EIS for compliance with NEPA's
rules and regulations.



Purpose and Need



The purpose of SMC's Proposed Action is to permit a flexible and integrated
waste management plan providing for long-term management of the disposal of
tailings, waste rock, and other wastes generated by the Stillwater Mine. SMC
needs to implement the Proposed Action because its current tailings



S-2



Summary

impoundment will reach capacity in 2003. The Proposed Action would increase
SMC's capacity for storing tailings and waste rock by almost 1 5 million tons and
17.5 million tons, respectively, and would allow the Stillwater Mine to operate
for about another 30 years at an average production rate of 3,000 tons per day or
as long as 50 years at an average production rate of 2,000 tons per day. The
Proposed Action would also give SMC some flexibility in its operations it does
not have currently.



History of the Project



SMC operates an underground platinum/palladium mine in Stillwater County,
Montana (Figure S-1). Current permits allow SMC to produce ore at an average
rate of 730,000 tons per year (tpy) or 2,000 tpd. At the mine's mill, SMC
upgrades the ore by crushing, grinding, floating, and drying to a concentrate.
This concentrate is then shipped by truck to a smelter and base metal refinery
(BMR) in Columbus, Montana, for further upgrading. From the BMR, SMC
ships the BMR product to Belgium for final refining.

SMC's original plan of operations was approved after completion of a Final
Environmental Impact Statement (final EIS) in 1985. The current proposal, if
approved, would be the tenth amendment to the original plan of operations and
permit. The previous amendments are:

001 — Approved and permitted June 30, 1986. This amendment relocated

mine and mill facilities. No increase in permit area or disturbed area
resulted.

002 — Approved and permitted September 8, 1986. This amendment allowed

excavation of a sand borrow area in the existing permit area. The
disturbed area has been reclaimed.

003 — Approved and permitted January 8, 1987. This amendment allowed

excavation of a second sand borrow area within the permit area and the
disturbance has been reclaimed.

004 — Approved and permitted February 24, 1987. This amendment

relocated the southern portion of the tailings impoundment toe dike to
higher ground along Mountain View Creek on previously-disturbed
land within the permit area.

005 — Approved and permitted March 2, 1989. This amendment was the first

major amendment since the original permit was issued. It increased
the permit area to 1,158 acres and permitted mining on the east side of
the Stillwater River. The total allowable disturbance was increased by
72 acres.

S-3



Summary



006 — Approved and permitted July 21, 1989. This amendment allowed

construction of a temporary sand slurry pipeline connecting the east
and west sides of the mine area. No increase in permit area or
disturbed area resulted.

007 — Approved and permitted November 15, 1990. This amendment

allowed construction of the three Stillwater Valley Ranch percolation
ponds and four monitoring wells. The permit area was increased
27 acres. The total allowable disturbance was increased by 7 acres.

008 — Approved and permitted on September 23, 1992. This amendment

allowed production to increase from 1 ,000 tpd to 2,000 tpd. It also
approved some expansion of support facilities, such as waste dumps,
the mill, and the tailings impoundment.

009 — Approved and permitted February 28, 1996. This amendment allowed

the construction of an underground connection between the east and
west mining areas. No increase in permit area or disturbed area
resulted.

Additionally, a minor amendment was approved to relocate the 5900 adit
southward onto private land in order to reduce the visual effects due to
development. The permit area was increased 48 acres and the total allowable
disturbance was increased by 2 acres.

Currently, the total permit area is 1,340 acres and 255 acres are permitted for
disturbance. However, only 120 acres have been disturbed by mining and
exploration.



Decisions to be Made

The Director of the DEQ and the Supervisor of the CNF must make a decision
on SMC's request to amend its permit. This decision will be documented in a
Record of Decision (ROD). The process will lead to one of the following
possible decisions:

1 ) approval of the proposed action amending the existing permit/plan of
operations,

2) approval of an agency alternative to the proposed amendment,

3) approval of either the Proposed Action or an agency alternative subject to
identified mitigation measures, or

4) denial of the proposed amendment (DEQ) or request for revision (CNF).

S-4



Summary

>- DEQ can deny the proposed amendment. The authority for denial
originates from the Montana Metal Mine Reclamation Act (MMRA)
and Montana's water quality and air quality statutes. In addition,
since 1982 DEQ and the courts have interpreted the Montana
Environmental Policy Act (MEPA) as supplementing the basis upon
which an operating permit under MMRA can be conditioned or
denied. This means that DEQ may also deny or modify the mine
operating permit under MMRA in order to avoid or mitigate an
impact that would significantly degrade the human environment.
The operator then has the option of revising the plan.

>> The Forest Service is not granted the authority to deny a Plan of
Operation or an amendment to a Plan of Operation (36 CFR 228,
Sub-Part A). This finding is based on numerous court cases. If a
proposed Plan of Operation or amendment to a Plan of Operation
(amendment) is found to conflict with regulation, policy, or federal
law, the Forest Service must notify the Operator or Claimant that a
revision of the proposed Plan of Operation or amendment is
required. The Operator or Claimant then has the option to either
modify the Plan of Operation or amendment and resubmit it for
approval or withdraw the Plan of Operation or amendment.

The proposal or an agency alternative, if approved, must comply with all
applicable federal and state air and water quality laws and regulations.



Agencies' Roles and Responsibilities

The DEQ and Forest Service are the lead agencies for this Environmental Impact
Statement (EIS). As discussed above, the Director of the DEQ and the
Supervisor of the CNF are the officials responsible for making a decision on
SMC's proposed amendment. A December 1 1, 1989, Memorandum of
Understanding (MOU) between the State of Montana and the USDA Forest
Service provides for the preparation of joint environmental analyses and the
sharing of information, personnel, and funds.

MEPA/NEPA Process, including Tiering

NEPA and MEPA are Federal and State laws that direct the CNF and DEQ,
respectively, to disclose the effects of proposed activities on Federal and State
lands to the public and officials making decisions concerning the proposal.

The NEPA/MEPA process began when SMC proposed to amend its current
operating permit/plan of operations. The agencies sought public input to help
identify environmental issues and concerns through the process called "scoping."

S-5



Summary



Scoping activities for this project included mailing a scoping document to parties
interested in or potentially affected by the proposal, holding a public meeting in
Absarokee, Montana, on September 24, 1996, and receiving the public's
responses.

In addition to public scoping, the agencies reviewed SMC's proposal for
"completeness." The purpose of this review was to ensure the information
contained in the proposal is adequate to complete the agencies' environmental
analysis under MMRA and to identify additional information needed to complete
an environmental analysis under MEPA. The environmental analysis phase of
the NEPA/MEPA process began after the proposal was declared "complete" on
January 28, 1997.

The regulations implementing NEPA and MEPA encourage tiering in EISs.
Tiering is the process of referencing information presented in other previously-
prepared NEPA/MEPA documents, such as EISs, to minimize repetition. This
EIS is specifically tiered to the documents identified in the following section.



Identification of Related Environmental Documents

Several EISs have been prepared for the Stillwater Mine. They include the EIS
prepared for the original operating permit/plan of operations and EISs prepared
in support of amendments to that permit/plan of operations. The EIS
summarized here was specifically tiered to the following environmental
documents:

>* Final Environmental Impact Statement, Stillwater Project, Stillwater

County, Montana. Prepared by the Montana Department of State Lands and
USDA Forest Service, Custer National Forest in 1985.

»* Preliminary Environmental Review/Environmental Assessment (PER/EA).
Stillwater Project East Side Adit Development. Prepared by the Montana
Department of State Lands and USDA Forest Service, Custer National
Forest in 1989.

>" Final Environmental Impact Statement, Stillwater Mine Expansion 2000
TPD, Application to Amend Plan of Operations and Permit No. 001 18.
Prepared by the Montana Department of State Lands, Montana Department
of Health and Environmental Services, and USDA Forest Service in 1992.

>- Final Environmental Impact Statement for the Stillwater Mining Company
Underground Valley Crossing and Mine Plan. Application to Amend Plan
of Operations, Permit No. 001 18. Prepared by the Montana Department of
Environmental Quality in 1996.



S-6



Summary

Public Participation and Scoping

The DEQ and the Forest Service consider public participation a crucial
component in defining the scope of the environmental analyses presented in this
EIS. The agencies first informed the public of SMC's proposal by mailing the
project's Scoping Document to the public in August, 1996. News articles about
SMC's proposal appeared in local and regional newspapers during the first week
of September. 1996. A Notice of Intent to prepare an EIS was published in the
Federal Register on September 19, 1996. A public scoping meeting was hosted
by the DEQ and the Forest Service in Absarokee on September 24, 1996. Public
field trips were hosted by SMC on November 14 and 15, 1996. Since that time,
two newsletters have been distributed to the agencies" mailing lists. The first, in
March, 1997, summarized the scoping process and identified the issues that had
been defined in response to the public comments received. The second
newsletter was issued in September, 1997, and it provided information on the
process of preparing the EIS.

DEQ and CNF reviewed and analyzed the comments they received during the
scoping process. Public response to SMC's proposal included 52 letters and
about 20 phone calls. Additionally, six people visited the Beartooth Ranger



Online LibraryMontana. Dept. of Environmental QualityStillwater Mine revised waste management plan and Hertzler tailings impoundment : draft environmental impact statement → online text (page 1 of 31)