[Federal Register Volume 61, Number 186 (Tuesday, September 24, 1996)]
[Notices]
[Pages 49999-50002]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24444]


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DEPARTMENT OF AGRICULTURE
Forest Service


Stillwater Mining Company Tailing Impoundment Expansion, 
Stillwater County, MT

AGENCY: Forest Service, USDA.

ACTION: Notice; intent to prepare an environmental impact statement.

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SUMMARY: The USDA, Forest Service, as co-lead agency with the Montana 
Department of Environmental Quality (MT DEQ) will cooperatively 
participate in the preparation of an environmental impact statement 
(EIS). The EIS will disclose the environmental effects due to 
construction and operation of a new tailing impoundment facility 
located approximately 7 miles northeast of the present Stillwater Mine 
facility. The area involved in this proposal involves both federal 
land, administered by the Forest Service, and private lands over which 
the MT Department of Environmental Quality has jurisdiction.
    The Director of the Montana Department of Environmental Quality and 
the Custer National Forest Supervisor are the officials responsible for 
approving SMC's proposal to construct and operate its tailing storage 
facility and other associated structures which are discussed in this 
Scoping Statement.
    The Forest Supervisor has the authority for regulating all 
activities and uses of National Forest system lands. The Custer 
National Forest Supervisor will decide whether to approve Stillwater 
Mining Company's amendment to their approved Plan of Operations as 
detailed in the Proposed Action, or whether to approve an alternative 
to the Proposed Action. The Forest Supervisor also has the ability to 
prescribe mitigation measures as conditions of approval.

DATES: A public meeting will be held in Absarokee, MT on September 24, 
1996 in order to identify issues to be addressed in this environmental 
analysis. Written comments concerning the scope of this analysis must 
be received by October 31, 1996.

ADDRESSES: Written comments concerning this analysis should be sent to 
Rand Herzberg, Beartooth District Ranger, Custer National Forest, HC 
49, Box 3420, Red Lodge, MT 59068.

FOR FURTHER INFORMATION CONTACT:
 Questions about the proposed action and EIS should be directed to Pat 
Pierson, Interdisciplinary Team Leader, Beartooth Ranger District. 
Phone (406) 446-2103.


[[Page 50000]]



SUPPLEMENTARY INFORMATION:

Purpose and Need for Action

    The Stillwater Mining Company has been in operation since 1986. SMC 
is currently in the process of expanding ore production from 1000 tons 
per day to 2000 tons per day. At the present rate of production, SMC's 
permitted tailings impoundment will reach its ultimate capacity by the 
year 2003.
    Given the projected life of the current tailing facility, SMC must 
proceed with the permitting of an additional tailings storage options 
in order to provide the capacity needed to manage tailings and waste 
rock in the long term. The purpose of this Proposed Action is to permit 
an integrated waste management plan to provide for the long term 
management of SMC's waste stream.
    SMC has submitted a proposal to amend its plan of operations in 
accordance with Federal and State regulations. The General mining law 
of 1872 grants all US citizens the right to explore, develop, and 
produce mineral resources on Federal lands open to mineral entry. SMC 
currently operates the only economically viable platinum/palladium mine 
in the western hemisphere, and accounts for five percent of world 
production. Thirty-five percent of US consumption of platinum/palladium 
is accounted for by the automotive industry in catalytic converters, 
required as a result of the Clean Air Act of 1990, 32 percent by 
electronics, nine percent is used for medical/dental purposes, six 
percent by the chemical industry, and 18 percent is used for a variety 
of purposes, based on their chemical inertness and refractory 
properties (USDI, 1991).
    The purpose of this environmental analysis is to disclose the 
environmental effects of Stillwater Mining Company's Proposed Action 
and alternatives to that Proposed Action. Although effects of other 
potential activities within the Stillwater Complex are included in this 
analysis, the decision document resulting from this environmental 
analysis will make a decision only on the proposed expansion.

Description of Proposed Activity

    The Stillwater Mining Company has submitted a proposal to the 
Forest Service and the Montana Department of Environmental Quality to 
construct and operate a new tailing impoundment at the Hertzler Ranch. 
The Hertzler Ranch is situated approximately seven miles northeast of 
the mine site. Construction of the Hertzler Impoundment would utilize 
local borrow materials, therefore this amendment proposes to store 
waste rock on permitted waste rock sites located on the east side of 
the Stillwater River. This area is currently occupied by a part of the 
mine waste water disposal system, known as the Land Application and 
Disposal system (LAD). Once construction begins on the east side waste 
rock storage area, the LAD system would be moved. To insure that 
production levels can continue uninterrupted and that operational 
flexibility is maintained, SMC will continue to utilize the existing 
tailing impoundment. As currently proposed, the two impoundments would 
be operated in concert.
    This amendment proposes to expand the current permit area to 
include the Hertzler Ranch. The existing mine permit area encompasses 
approximately 1,340 acres. Within this area, approximately 255 acres 
will ultimately be disturbed by permitted mining activities. Of this 
255 acres of disturbance, well over 120 acres have been disturbed by 
past mining and exploration activities. This amendment will result in 
approximately 271 acres of additional disturbance and will increase the 
total permitted acreage by 1,112.
    Past amendments to SMC's original Plan of Operation have utilized a 
defined production rate as a means to quantify and qualify the possible 
environmental impacts due to construction and operation of the mine 
facility. This approach has limited SMC's operational flexibility and 
made it difficult to take advantage of the economic scale inherent 
during mine expansion. Consequently, this amendment proposes to 
establish a project footprint within production rates, but will be 
variable as dictated by project economics and infrastructure capacity.

Tailing Impoundment

    Construction of the proposed tailing embankments will incorporate 
staged expansion using local borrow materials, identified during the 
1981 site investigation program. The embankment would be constructed 
using the centerline method to a height of approximately 155 feet 
(elevation 5,036 feet) at the deepest section and would accommodate 
storage of approximately 13 million cubic yards (12.3 million tons) of 
tailings. This facility will cover approximately 146 acres after 
construction.
    SMC is proposing to utilize a high density polyethylene (HDPE) 
liner within the impoundment. A system of spine underdrains would be 
incorporated to promote consolidation of the tailings mass during 
operations. Seepage collected from the underdrains and from the 
embankment filter drains would drain to recycle ponds situated around 
the perimeter of the facility. From the recycle ponds, this tailings 
water would be pumped back to the tailings impoundment for reuse in the 
milling and concentrating process.
    Reclamation of the outer embankment slope will be conducted 
concurrently with operations of the facility, thereby minimizing 
impacts and fugitive dust. A minimum of 12 inches of soil and/or sub-
soil will be stripped and stored for final reclamation prior to the 
excavation of the impoundment or borrow areas. Final reclamation of the 
waste storage site will incorporate waste rock and vegetation in a 
mosaic pattern similar to that permitted on the existing tailing 
impoundment.
    Post closure settlement is predicted to vary between 1 to 10 feet, 
depending on the distribution and final depth of tailings within the 
impoundment. Therefore, an average surface capping layer of 
approximately five feet will be required (including two feet of 
topsoil).

Mine Waste Rock Production and Management

    Waste rock from the mine which is not used for construction of 
portal pads, roads, mine backfill, or other uses, has typically been 
utilized in the construction of the tailing embankment. However, due to 
the long haul distance between the place of waste rock origin (mine 
location south of Nye) and the place of use (Hertzler location) waste 
rock will not be utilized in the construction of the new tailings 
impoundment. Therefore, this proposal includes provisions to increase 
the size of the east side waste rock pad and visibility berm permitted 
in the 2,000 tons per day Environmental Impact Statement and Record of 
Decision. Expansion of the East Side waste rock storage site would add 
approximately 10 million cubic yards of storage capacity and would 
encompass an area of approximately 80 acres.
    The East Side waste rock facility would be constructed in a phased 
approach as outlined below:

Stage 1 Construction

    Will consist of the placement of a visibility and containment berm 
to approximately the 5,000 feet elevation level. This visibility berm 
would be constructed to approximate a natural feature. Vertical and 
horizontal relief will vary in order to break up visual lines.
    Once completed, the visibility and containment berm will be 
topsoiled and revegetated. The toe of the berm will be placed a minimum 
of 100 feet from riparian zones.

[[Page 50001]]

    Embankment slopes will vary between 3h:1v to 2h:1v, with shallower 
slopes maintained along the Stillwater River corridor to minimize 
erosion during potential maximum flood (PMF) events. Erosion control 
will be provided through revegetation of the berm and by placing rip 
rap in drainage areas to prevent stormwater run-off. Existing 
monitoring wells and piezometer locations covered by the waste 
stockpile construction will be either relocated, capped, or extended.
    A portion of the emergency pipeline containment pond, which was 
designed to contain stormwater and spillage from the pipelines crossing 
the Stillwater River, will be partially inundated by the Stage 1 berm. 
The remaining storage capacity in this area will exceed one million 
gallons and will provide over 41 hours of emergency storage at a 
pumping rate of 400 gallons per minute.

Stage 2 Construction

    Construction would continue as in Stage 1. The berm would continue 
to be located a minimum of 100 feet from riparian vegetation. 
Construction would continue to resemble a natural feature by varying 
horizontal and vertical lines. Embankment slopes would vary between 
3h:1v to 2h:1v. Monitoring wells, storm water collection ponds, and toe 
ditches will be added along the downstream slopes of the waste 
embankment. Montana Power's utility line would be relocated to the 
downstream toe of the embankment.

Stage 3 Construction

    During the Stage 3 construction phase, the waste rock storage area 
will be raised to approximately the 5,050 feet elevation, with no 
further extension of the Stage 1 and Stage 2 toes. The visibility and 
containment berm would be constructed with slope gradients varying from 
3h:1v to 2h:1v and revegetated. Waste rock placement would be conducted 
in lifts behind the berm and each lift would be graded and compacted by 
a dozer. The compaction of each lift will minimize fugitive particulate 
emissions from the pad and water infiltration due to precipitation. 
Selective shaping of the top cap will sculpture areas of the embankment 
to approximately the 5,080 ft. elevation. By varying the elevation of 
the cap, the final pad would blend with the natural terrain.

Pipeline Systems

    The pipeline system will consist of five pipelines and extend for 
approximately 34,000 feet. Two pipelines will be dedicated for slurry 
transport, one pipeline for mine water (LAD), one for return reclaim 
process water and one line will be utilized as a spare. The pipelines 
will range from 6 to 12 inches in diameter. The pipeline system will be 
located along Stillwater County roads 419 and 420 right-of-way and be 
buried at a depth of approximately five feet (below the frost line). 
The pipeline system will include flow, moisture, and pressure 
instrumentation along with inspection ports of physical pipe wear 
measurements. In areas of potential environmental concerns the pipeline 
system will be either double lined and/or placed in a conduit system. 
Emergency containment facilities will be placed on both sides of river 
or stream crossings and near any booster pumping station.
    Pipeline material will be either steel or high density polyethylene 
(HDPE). HDPE offers advantages of lower friction, greater abrasion 
resistance, no corrosion problems, and generally lower installation and 
purchase cost. A HDPE pipeline would require the installation of a 
booster pump station due to the line pressure restrictions inherent to 
HDPE pipe.
    Steel pipe offers an advantage over HDPE with its ability to 
support higher pressures. Use of an all steel pipeline could allow a 
single high pressure pump station to be installed at the thickener, 
eliminating the need for a booster pump station somewhere along the 
pipeline corridor. A collection pond together with a reclaim system 
would be required at the mid-point of the line. This facility would 
allow for a pipeline to be drained in the event of a line rupture.
    Reclamation will be conducted concurrently with pipeline 
construction. Following compaction of fill over the pipelines, 12 
inches of salvaged soil will be replaced and seeded. Seeding of the 
reclaimed pipeline trench will conducted utilizing SMC's approved low 
elevation seed mix.

Forest Plan Direction

    The area involved in this proposal is within Management Area E as 
described in the Custer National Forest Land and Resource Management 
Plan (1986). The management goal for Management Area E is as follows:

    To facilitate and encourage the exploration, development, and 
production of energy and mineral resources for the National Forest 
System lands. Other resources will be considered and impacts will be 
mitigated to the extent possible through standard operating 
procedures, and on a limited basis, through special lease 
stipulation necessary to manage key surface resources. Energy/
mineral development will not be precluded by these resource concerns 
within legal constraints. Efforts will be made to avoid or mitigate 
resource conflicts. If the responsible official determines that 
conflicts cannot be adequately mitigated she/he will resolve the 
conflict in accordance with the management goal and, if necessary, 
in consultation with affected parties (Forest Plan, page 58).

Preliminary Issues

    The Forest Service and Department of Environmental Quality 
Interdisciplinary Team (IDT) has preliminarily identified five issues 
which will be addressed in the environmental analysis. These issues 
have been identified due to the possibility that the existing 
environmental conditions related to these issue areas may change as a 
result of the construction, operation, and reclamation of the Hertzler 
Tailing Impoundment facility. These issue areas include;
    Water Quality and Quantity; Aesthetics (Including Noise, Air 
Quality, and Visual Effects); Tailing Impoundment Stability; Social/
Economic Effects; and Wildlife and Fisheries.

Preliminary Alternatives

    Potential tailing impoundment locations for Stillwater Mining 
Company's mine have been explored since the early 1980's. These 
previous site investigations include those conducted by Wahler 
Associates (1981), the US Forest Service and the Montana Department of 
State Lands during development of the 1985 EIS, the US Forest Service 
and the Montana Department of State Lands during the development of the 
1992 EIS, and recent investigations, undertaken by Knight Piesold for 
this proposed amendment to SMC's Plan of Operations.
    After reviewing past studies, Knight Piesold (1996) concluded that 
the evaluation process should be expanded to include consideration for 
the disposal of both tailing and waste rock in the overall waste 
management strategy. As a result of the 1996 Knight Piesold 
investigation, four waste management alternatives were selected for 
further study by Knight Piesold. The four management alternatives, 
incorporating tailings impoundment options selected from the previous 
assessments are summarized below:
    Option A: Expansion of the existing tailing impoundment by Modified 
Centerline construction, with concurrent development and operation of a 
new tailing facility at the Hertzler Ranch site.
    Option B: Expansion of the existing tailing impoundment by 
Centerline construction and extension of the

[[Page 50002]]

downstream toe, and concurrently development and operation of a new 
tailings facility at the Hertzler Ranch site.
    Option C: Expansion of the existing tailing impoundment by Modified 
Centerline construction, and concurrent development and operation of a 
new tailings facility located on the East Side of the Stillwater River.
    Option D: Development of a new tailings facility at the Hertzler 
Ranch site, with some tailings disposal into the existing permitted 
impoundment when required to facilitate ease of operations (Proposed 
Action).
    Each of these alternatives includes development of a new tailings 
impoundment and expanded waste rock storage capacity in order to 
provide sufficient storage for long term operations.

EIS Availability

    The draft environmental impact statement (DEIS) is expected to be 
available for public review during the spring of 1997. After a 45 day 
public comment period, the comments received will be analyzed and 
considered by the Forest Service and Montana Department of 
Environmental Quality during the preparation of the final environmental 
impact statement (FEIS). The FEIS is scheduled to be completed by the 
fall of 1997. The regulatory agencies will respond to the comments 
received in the FEIS. The Custer National Forest Supervisor and the 
Director of the Montana Department of Environmental Quality are the 
responsible officials for this EIS and will make a decision regarding 
this proposal considering the comments and responses, environmental 
consequences discussed in the FEIS, and applicable laws, regulations 
and policies. The decision and reasons for the decision will be 
documented in a Record of Decision.
    The comment period on the draft environmental impact statement will 
be 45 days from the date the Environmental Protection Agency publishes 
the notice of availability in the Federal Register.
    The Forest Service believes it is important to give reviewers 
notice at this early stage 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 the agencies to 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. Wisconsin Heritages, Inc. 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 on the draft 
environmental impact statement should be as specific as possible. It is 
also helpful if comments refer to specific pages or chapters of the 
draft statement. Comments may also address the adequacy of the draft 
environmental impact statement or the merits of the alternatives 
formulated and discussed in the statement. (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.)

    Dated: September 11, 1996.
Nancy T. Curriden,
Forest Supervisor, Custer National Forest.
[FR Doc. 96-24444 Filed 9-23-96; 8:45 am]
BILLING CODE 3410-11-M