2.1.1 Narrative
The EPA Emergency Response Section conducted a CERCLA removal action of uranium mine waste from two former transfer stations located in the Cove Chapter of the Navajo nation in Sept. 2012. EPA removed most of the waste from TS1 and moved it to TS2. The waste at TS2 was excavated and consolidated into several stockpiles. The stockpiles were constructed to a 4:1 ratio and stabilized with soil sealant, fenced, and warning signs were placed on the perimeter fencing. This removal was not completed due to the discovery of previously undetected contamination. EPA demobilized off the site November 2012. A second action memo increasing the ceiling amount was approved in June 2013. EPA and the removal contractors remobilized on June 10, 2013. Removal action commenced on June 12, 2013.
2.1.2 Response Actions to Date
See PolReps 1-8
Summary of START activities at Cove Transfer
Station (TS) Removal Week of 6/19-6/22
06/19/13- Performed Daily QA/QC on all instruments. Count previous two days
air samples, no exceedance of applicable DACs for gross alpha or gross beta.
Upwind, downwind, and work zone air sampling performed for gross alpha and beta
activity. All DACs are below applicable limits. One air sample location
(TS1N-03) was moved across the road to in front of the school. Downwind and
work zone dust monitoring for PM10. One DataRAM did not data log (at location
TS-02). All other DataRAM PM10 concentrations less than stipulated action
levels.
Performed final RAT
Gamma Activity scan at TS1W-06. Results were below the action level.
Post-excavation RAT scan at TS1N-07. Collect 3 confirmation soil samples
(including one duplicate) from TS1N-07. Samples to be submitted for analysis
for Ra-226 to GEL (laboratory). Perform delineation RAT scan on TS1-S-02 to
mark areas for excavation. START scans erosion rills near TS1N. Options to
control erosion discussed, ERRS used loader to add borrow material to fill
rills.
06/20/13- Performed Daily QA/QC on all instruments. Count previous two days
air samples, no exceedance of applicable DACs for gross alpha or gross beta.
Upwind, downwind, and work zone air sampling performed for gross alpha and beta
activity. All DACs are below applicable limits. Downwind and work zone dust
monitoring for PM10. TWA dust concentrations less than stipulated action
levels. One DataRAM did not data log for this date (at location TS2-02).
Perform delineation
gamma activity scan at TS1-S-02 using USEPA’s RAT. START marks areas for
further excavation as gamma activity ranged between 40,000 and 55,000 cpm,
which is equivalent to 5-12 pCi/g (background is 25,000-27,000 cpm or 0.7-2
pCi/g). Elevated areas most likely due to historic ore pit identified as
TS1S-01. Approximately 15 cu. yd. were excavated from TS1-S-02.
Clean fill rock
material arrived to site via haul truck. Work began spreading fill rock along
drainage gully north of TS1-S1 (north of historic ore pit).
06/21/13- Performed Daily QA/QC on all instruments. Count previous two days
air samples, no exceedance of applicable DACs for gross alpha or gross beta.
Upwind, downwind, and work zone air sampling performed for gross alpha and beta
activity. All DACs are below applicable limits. Downwind and work zone dust
monitoring for PM10. DataRAM PM10 concentrations less than stipulated action
levels.
One resident visited
the site and requested a scan of a portion of her property. START and OSC accompanied
resident with Ludlum 2241-3/44-90 to perform hand scan. The area scanned was
located across the road and immediately southeast of TS2. Hand scan results were
between 26,000 and 30,500 cpm, which is considered background for the area.
Performed additional final gamma activity scans and soil sampling at
TS1-North-02&03 (TS1-N-02&3) using USEPA’s RAT. Zones 2 and 3 were
combined due to proximity.
To the south of TS1N2
and N3 was a localized (~2 foot diameter) area of exposed ore discovered with
800,000 cpm. ERRS was notified of the area and will remove using a shovel.
Final RAT scan of TS2-02 along the road indicated areas exceeding twice
background. START marks elevated areas. ERRS was notified of the area and plans
to place one foot of additional cap material on the elevated areas.
Approximately 216 cu.
yd. were excavated from TS1 between 6/19 and 6/22. Collected an additional 4
soil samples from TS1-S1. Gamma activity generally less than approximately
33,000 counts per minute (background is 25,000-27,000 cpm) in all areas except
TS1-N-06. All removal work is completed in zones 2&3, 4, and 5.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
Not Applicable
2.1.4 Progress Metrics
Cove Transfer Stations Removal Volumes to Date
|
|
Truckloads
|
Excavated Volume*
|
Transported TS2 Volume*
|
6/19/2013
|
25
|
180
|
300 |
6/20/2013
|
3
|
36
|
36
|
6/21/2013
|
0
|
0
|
0 |
6/22/2013
|
0
|
0
|
0 |
*12 yds3/truckload
|
