Maury Island Gravel Mine Draft EIS



Northwest Aggregates (Lone Star Northwest) has submitted a
request to King County to significantly increase mining over
current levels at its Maury Island sand and gravel mine. King
County issued a Determination of Significance (DS) for the
proposal on August 11, 1998, based on its review of the project
grading plan and environmental checklist dated May 1998 (this
checklist is available for review at the Vashon library). The DS
documented the County's determination that significant
environmental impacts could result from the proposal and an
environmental impact statement (EIS) is required. This EIS is
being prepared to meet the requirements of the State
Environmental Policy Act (SEPA), per Washington Administrative
Code, Chapter 197-11.
The proposal would require revisions to the applicant's existing
King County Grading Permit and their existing Surface Mining
Reclamation Permit issued by the state Department of Natural
Resources (DNR), as well as a Shoreline Substantial Development
Permit through King County.

Proposal Objectives

Lone Star Northwest wishes to increase its maximum production
rate at the Maury Island mine from roughly 10,000 tons of sand
and gravel per year (the level of production that has occurred in
recent years) to up to 7.5 million tons per year (that is, 5.5 million
cubic yards).
The applicant also wishes to be able to barge mined materials 24
hours a day, 7 days a week. This level of barging, which would
occur periodically as contracts are awarded and completed,
increases the applicant's ability to win contracts and to take
advantage of peak demands in a variable market.

Purpose and Need

The applicant's purpose and need for this project is to meet the
anticipated high market demand for sand and structural fills
(materials which are abundant on the site). While the applicant
operates several mines in the region, the Maury Island site contains
a high amount of quality fills, products that are not as abundant at
other sites operated by the applicant.

Summary of Proposal and Alternatives

This environmental impact statement (EIS) analyzes the
applicant's Proposed Action, two additional alternatives that
include mining with reduced hours of barging, and the No-Action
Alternative. Each of these alternatives is described below.
Features of the alternatives are summarized in Table S-1 at the end
of this chapter.

Description of the Proposed Action

Scale of Operation

Under the Proposed Action, sand and gravel extraction could
approach 7.5 million tons per year (or 5.5 million cubic yards),
with essentially all of the increased material being sent to off-island
markets via barge. No barging has been conducted at the
site for 20 years, although the dock used during previous barging
remains onsite. Mining rates would depend on the number of large
sand and gravel contracts for off-island markets.
For purposes of predicting the environmental effects of the mining
operation, this EIS assesses the site at full production with the
mining and barging of 7.5 million tons per year.
When demand for sand is low, the level of operation at the site
would also be low. It is even likely that the site would be idle for
periods of time, again depending on the market.
It follows that the overall life span of the mine depends on market
conditions and the number of large sand and gravel projects
secured by the applicant. At full production, the site deposits
could be mined out in 11 years. Of course, the lower the level of
production, the longer the operation could last. The analysis in
this EIS assumes a 35-year operating window before the site is
As under current practices, operations would also provide
materials for the local market (Maury Island and Vashon Island).
The amount of sand and gravel extracted for the local market was
estimated to average approximately 15,000 tons in 1998 (range of
10,000 to 20,000 tons per year) with an annual increase assumed to
be 2.5 percent for this EIS analysis; actual increases would depend
on market needs and local growth. This would be delivered via
truck, at a rate not to exceed 20 trucks per day. At some point, the
increase in extraction for the local market would slow and
eventually halt, since demand for sand and gravel within the
confines of Vashon/Maury Island is limited.

Clearing and Ground Preparation

Clearing of the site would be phased with mining activities.
Clearing would occur at scheduled phases of approximately 32
acres each. No more than two phases, or 64 acres of
mining/reclamation activities, would be in process at any one time.
Prior to mining of each approximately 32-acre phase, vegetation
would be cleared and chipped onsite to be used in reclamation.
Some large woody material (stumps and logs) would be kept intact
to be used as part of the restoration effort, aiding in soil stability,
soil organic content, and wildlife habitat.
To address public safety concerns regarding arsenic contamination
of site soils, the applicant is proposing to fully contain
contaminated materials at the site within a sealed berm. No
contaminated materials would be removed from the site. At full
capacity (when mining is complete), the berm would measure up to
30 feet high and 2,100 feet long. The berm would be located on the
northern edge of the site, but outside of the 50-foot vegetated
buffer (see next paragraph), which would be maintained.
Along the edge of the mining pit, a 50-foot-wide naturally
vegetated buffer would be retained around the perimeter of the site.
With the exception of the existing dock area, a 200-foot-wide
naturally vegetated buffer would be retained along the Puget
Sound shoreline. No mining or other activity would be permitted
within this buffer.
Maintenance of the 200-foot shoreline buffer and a 50-foot buffer
between the site and neighboring properties would result in
approximately 14 percent of the site being retained as open space
and upland habitat.
Table S-1 outlines other major features of the Proposed Action.

Alternative 1 - Reduced Barging Hours, Scenario 1

Alternative 1 differs from the Proposed Action in that barge
loading would be restricted to 16 hours each weekday and 9 hours
on Saturday (Monday  Friday 6 a.m. to 10 p.m., Saturday 9 a.m.
to 6 p.m.). This alternative was developed by the EIS team in
response to public comments and is intended to allow the
applicant, public, and decision makers at King County to compare
the environmental impacts of the Proposed Action to this
hypothetical scenario of reduced hours for barge loading.
The reduced hours would reduce the ability of the applicant to
provide sand and gravel products on demand, and, therefore, does
not meet the applicant's project objectives as well as the Proposed
Action. The applicant's daily capacity to move material offsite
during peak demands would be about half that of the Proposed
Table S-1 compares other features of this alternative with the
Proposed Action.

Alternative 2 - Reduced Barging Hours, Scenario 2

Under Alternative 2, barge loading would be restricted to 12 hours
each weekday and on Saturday (Monday - Saturday 7 a.m. to 7
p.m.). As with Alternative 1, Alternative 2 would reduce the ability
of the applicant to provide sand and gravel products on demand,
and, therefore, does not meet the project objectives as well as the
Proposed Action.
The applicant's capacity to move material offsite during peak
demands would be only about one-quarter that of the Proposed
Action. Again, as with Alternative 1, this may affect the operation
in two ways, but potentially at a greater level than with
Alternative 1. First, the applicant may receive fewer contracts than
under Alternative 1, since the 75 percent reduction in maximum
daily production rate may be too low to meet the required delivery
schedules of certain contracts. Secondly, for contracts that are
secured, the mine would need to operate at maximum capacity for
approximately four times the period that would be required under
the Proposed Action.
Table S-1 compares other features of this alternative with the
Proposed Action.

No-Action Alternative

Under SEPA, King County must evaluate the "No-Action
Alternative", which is defined by the state SEPA Handbook as
"what would be most likely to happen if the proposal did not
Because the SEPA rules do not define what the No-Action
Alternative must entail, King County has some discretion in its
formulation. The applicant already has a permit to extract sand
from the site up to roughly 50 feet from the property boundaries
(200 feet from the shoreline). For the purpose of comparative
analysis and to understand the environmental effects of the
applicant's proposal, this EIS considers the No-Action Alternative
as the status quo, or essentially how the mine has operated on
average over the past 20 years.
It is important to note that should King County decide to not
approve the applicant's proposal, something other than the No-Action
Alternative evaluated here may result, particularly in light
of the current and expected high demand for gravel in the Puget
Sound region. However, it would be highly speculative to predict
exactly what would result following possible legal challenges or
other forms of negotiations. King County determined that to
attempt to predict a level of operation that may result from denying
the current proposal would confuse the issues, rather than clarify
them. Therefore, No-Action is evaluated in this EIS as a
continuation of current mining levels and practices.
No-Action, then, assumes ultimate excavation and resource
recovery of the mine identical to the Proposed Action, but over a
much longer period. It would result in a similar level of terrestrial
impact, over a much longer period. The most significant difference
under No-Action is the assumed lack of barging. (Again however,
this is not to say that barge loading would be prohibited if the
applicant's proposal is denied. The applicant's existing mining
and barging rights are not necessarily limited to the No-Action
The features of the No-Action Alternative are summarized and
compared to the Proposed Action in Table S-1.

Significant Areas of Controversy and Issues to be Resolved

As required under SEPA (WAC 197-11-408), King County
conducted scoping to "narrow the scope of [the] EIS to the
probable significant adverse impacts and reasonable alternatives,
including mitigation measures." Toward this end, King County
invited agencies, affected Tribes, and members of the public to
comment on the Determination of Significance (WAC 197-11-
The major controversial issues identified during this process
include groundwater supplies, visual and noise disturbances,
arsenic contamination of topsoils, removal of madrone forest, and
potential effects on marine habitat. These issues, and others
questions raised during scoping, are listed at the beginning of
Chapters 3 through 12 of this EIS in the sections titled "Primary
Issues". These issue questions are then addressed in the impact
analysis in each chapter.

Phased Review

No phased review is anticipated.

Summary of Impacts, Mitigation, and Significant Unavoidable Adverse Impacts

Tables S-2 through S-11 at the end of this chapter summarize
impacts, mitigation, and significant unavoidable adverse impacts
for each of the alternatives.

I didn't include the tables;
go get 'em here -- you'll need Acrobat Reader...

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