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2.1.1 Narrative
2.1.2 Response Actions to Date
2.1.2.a Removal actions were undertaken by the Oregon Department of Environmental Quality (ODEQ) in 2000 and 2014. For additional information and details please see PolReps 1 through 5.
2.1.2.b. The following removal actions have been undertaken by EPA as part of this ongoing removal action for the first phase of the current reporting period: October 12 - 25, 2014.
The primary activities during this period included the following
tasks:
- Accept delivery of nearly 5 acres of 40-millow-density
polyethylene (LDPE) geomembrane liner and 200-mil geonet liner to cover
repository.
- Receive results from an off-site geotechnical
laboratory regarding sheer tests for the liner material and recalculate
acceptable soil cap thickness for the repository.
- Survey the site boundary to assist with the placement
of two manufactured homes and identify potential borrow sources of clean fill
to cover the on-site repository.
- Utilize a borrow source of up to 20,000 cubic
yards of clean fill adjacent to the EPA command post to cover the on-site
repository.
- Excavate utility trenches leading to Residence
1 and Residence 6 homesites.
- Perform additional screening with the Lumex
mercury vapor analyzer at Residence 1, Residence 6, and the mill site to continue to assess ambient mercury vapors on
site.
- Deploy both the geomembrane liner and 200-mil
geonet liner on the repository.
- Begin to place the soil cap on the repository.
- Demolish and reconstruct the pumphouse south
of Area 4.
- Coordinate the inspection and purchase of the
replacement manufactured home at the Residence 6 homesite.
- Continue to search for a suitable replacement
manufactured home at the Residence 1 homesite.
From October 13 to 16, the START subcontract
surveyor, Centerline Concepts, performed a survey of the site boundary. The
purpose of the survey was to assist with potential placement locations for the
two manufactured homes and identify potential on-site borrow sources for the
repository soil cap.
On October 13, the START PM and ERRS RM used
the Lumex mercury vapor instrument to screen ambient mercury vapors at
Residence 1, Residence 2, Residence 6, and the mill site; all locations were
less than 100 ng/m3 which was markedly less than the NIOSH REL of
50,000 ng/m3 and the ATSDR level for normal occupancy of 1,000 ng/m3.
Rain showers and wet site conditions resulted
in intermittent delays during the operation period. The final deployment of the
DataRam particulate monitors occurred on October 13 because the repository was
fully covered with clean soil and the airborne threat of arsenic and mercury
particulates was mitigated. In addition, the DataRams cannot be deployed during
rain showers.
ERRS continued to add subgrade and wearing
course material to Residence 1 and Residence 6 to prepare for the replacement
manufactured homes. The haul road leading from Area 2 to the mill site was
reinforced to accommodate haul trucks carrying borrow source material to the
top of the repository.
On October 15, EPA received results from an
off-site geotechnical laboratory regarding sheer tests for the liner material.
A START engineer then assessed a proposal to potentially decrease the soil cap
thickness of the repository from 24 inches to 12 inches based on the
availability of on-site borrow material. Although the revised repository
specifications allowed for the shallow soil cap, the eventual soil cap
thickness did not change from the original design.
On October 16, the first section of geomembrane
liner was placed on the repository. By the end of the day, approximately 75% of
this liner was deployed including fusion of the seams using a propriety heat
gun. The following day, the geonet liner was deployed on top of the geomembrane
(it rained overnight, and the remaining section of geomembrane liner could not
be deployed because the seams needed to be dry in order to be fused). ERRS
began to excavate soil from the borrow source on October 18 to place in the
upper anchor trenches to secure the liners and by mid-day October 19, both
liners had been completely deployed. ERRS continued to place borrow material on
the repository for the next three weeks until it was completely covered with 24
inches of soil.
The pumphouse located south of Area 4 was in
disrepair and infested with rodents. EPA directed ERRS to demolish the
pumphouse and replace it with a new weather-resistant pumphouse, which occurred
on October 17.
The local power company and communications
provider visited the site on October 17 to assess reconnection of services for
Residence 1 and Residence 6. The power company confirmed that the current power
poles were sufficient, and the transformers did not need to be moved or
replaced. However, an additional service pole would still need to be from the
power pole by an ERRS subcontractor during a future reporting period to connect
Residence 6 to the power pole. On October 23, a representative from the
communications provider arrived on site to install phone line from Area 2 to
Residence 6.
On October 25, the ERRS RM completed the
purchase of a 2 bedroom, 2 bathroom replacement manufactured home for the
Residence 6 homesite. It was delivered to the site during the following
reporting period. The search for the final replacement manufactured home
continued.
2.1.2.c. The following removal actions have been undertaken by EPA as part of this ongoing removal action for the second phase of the current reporting period: October 27 - November 9, 2014.
The primary activities during this period included the following tasks:
- Completion of the
repository soil cover.
- Installation of the upper
repository run-on control ditch, the repository side perimeter ditches, and
other armored drainage channels on the site.
- Construction of the repository
toe drain and toe surface drainage channel.
- Placement of a manufactured
home at Residence 6.
- Installation of the shared
septic system drain field, and placement of septic tanks at Residence 6 and
Residence 1.
- Grading, reclamation,
and surface restoration of disturbed areas.
- Maintenance of the site
roadways during construction activities.
Rain showers and wet
site conditions resulted in intermittent delays during operation period. Task
scheduling was assessed daily based on current conditions and weather forecasts
in consideration of site safety, and to avoid damage to the site from working
in unsuitable conditions. ERRS hauled cover soil from the on-site borrow source
west of the command post, and placed the soil on the repository. The soil was
transported to the repository using two articulated haul trucks, dumped onto
the previously placed cover soil, and pushed over the geomembrane/geonet liner
system with a low-ground pressure dozer in an approximately 30 to 36-inch lift.
Cover soil was placed on the liner system starting from the bottom of the
repository slope in approximately 50-foot wide section, and then placed
progressively upward over the liner until covering to the top of the slope. As
each section was completed, the fill operation was shifted to the adjacent
sections to the northwest, again placing cover soil starting from the bottom of
the slope and working upward. The sections of cover soil were compacted using a
smooth-drum roller compactor, in a single, full-thickness lift.
On November 1, 2014,
tension and three seam separations were noted in the geonet liner sections in
northeastern portion of the repository. No damage or stretched areas of the
underlying geomembrane material was observed during inspection of the separated
seams. Separated seams were covered with non-woven geotextile to prevent direct
contact of cover soil and geomembrane, and to prevent sediment migration into the
geonet. Cracks were noted in the surface of the compacted cover soil in the
northeastern portion of the repository. The cracks were oriented in a
North-South direction, 45-degrees from the up-down slope direction. The cracks
were more prevalent in the upper two thirds of the slope, but also occurred near
the lower portion of the slope. ERRS elected to fill in the toe drain trench
with soil as a preventative measure to buttress slope soils. The toe trench was
covered over with borrow soil, and compacted using the roller compactor.
Additional work on the
repository cover soil was postponed for several days due to rainy weather and
unfavorable soil conditions. The repository soil cover was completed on
November 5, 2015. Due to project time
and budget constraints, and limited availability of suitable import top soil,
the 6-inch top soil was omitted and additional borrow soil was included to
serve as the final surface cover. During a later work phase, prior to placing
slash, seed, and straw, and a fertilizer soil amendment will be added to
improve vegetation growing conditions. A START subcontract surveyor, Centerline
Concepts, conducted a repository surface topographical survey on November 7,
2014. The surveyor also located and marked the soil-backfilled repository toe
drain trench.
The upper repository
run-on control ditch and the southern side drainage channel, were constructed
by shaping the drainage features in the fill soil, and armoring the bottom and
sides with 4 to 8-inch rock. The northeastern 30-foot segment of the run-on
control ditch will be completed later, to allow for construction equipment
access during slash placement.
A replacement manufactured
home for Residence 6 was transported to the site on October 31, 2014. The home
was moved to its final location by the moving contractor using a remote
controlled tractor. Positioning the unit into the Residence 6 driveway required
ERRS to add road material at the intersection to allow trailer clearance. On
November 3, 2014 an ERRS subcontractor installed the vapor barrier, support
blocks, and hurricane straps. Additional installation tasks for Residence 6 manufactured
home were conducted between November 3 through November 9, 2014. ERRS installed
front and rear steps, roof gutters and downspouts, and made roof repairs. The electrical subcontractor installed a
power service pole and meter at Residences 1 and 6. START conducted a mercury
air monitoring survey in each room of the Residence 6 manufactured home using
the Lumex mercury vapor analyzer. No elevated mercury readings were seen. Remaining tasks for Residence 6 include
power, telephone, and water utility connections, and installation of the
trailer skirting. A replacement manufactured home for Residence 1 was
identified by EPA. The purchase closing is expected to occur on November 12,
and transportation to the Site on November 20, 2014.
ERRS’ septic system
subcontractor, Randy Arts Excavating, prepared and installed the drain field
and leach lines northeast of Bonanza Mine Road, south of Area 4. The excavation
and backfilling was done during times of dry weather during the operational
period, and was completed on November 8, 2014. A septic tank was installed at
Residence 6 on November 6, 2014, and at Residence 1 on November 8, 2014. Each
tank was filled with water the day of installation.
After removing the soil
needed for the repository cover, ERRS began reclaiming the soil borrow source west
of the command post. Slopes were blended to the surrounding topography, and the
drainage swale toward the northeast was reestablished. The excavator operator
dispersed slash over the bare slopes. On November 7, 2014 and a hand crew
placed seed and straw in this area and around the periphery of the command post.
Other work accomplished
during this operation period included maintain the roadways by removing mud and
placing rock as required to accommodate construction traffic and to reduce
sediment run off. Bare areas, including the Former Mill Site, road shoulders,
and banks were seeded and covered with straw.
On November 10, 2014 the
repository was track-walked and back-bladed with a LGP bulldozer to remove
surficial erosion rills and texture the surface. A 16:16:1 fertilizer pellet
blend was applied to the soil surface, and a turf grass seed mix was broadcast
over the repository. The slash that was
preserved and stockpiled from the initial repository area preparation was
distributed over the repository surface using the mini-excavator.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
EPA has initiated a PRP search for this Site.
2.1.4 Progress Metrics (as of 11/10/14)
Waste Stream |
Medium |
Quantity |
Manifest # |
Treatment |
Disposal |
Commingled mercury waste |
Soil
and other debris removed using hand tools
|
(2) 55-gallon drums |
- |
Macro-encapsulation |
RCRA Subtitle C Facility (TBD) |
Commingled mercury waste |
Soil and other debris removed using Hg recovery vacuum |
(1) 5-gallon pail |
- |
Retirement (sulfide treatment) |
TBD |
Mercury soil waste |
Soil and other debris |
(2) 55-gallon drums |
007851712 FLE |
|
Bethlehem Apparatus Co. |
Mercury wood debris |
Soil, wood, and other debris |
(2) 55-gallon drums |
007851711 FLE |
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Clean Harbors Grassy Mountain |
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