DSHW-2008-025230 - 0901a068801e2228 (5)

December 29, 2008

David P. Gosen, P.E.
Director, Environmental Services
ATK Launch Systems – Promontory
P.O. Box 707
Brigham City, UT 84302-0707

RE: ATK’s Response to Operation and Maintenance Inspection Letter
ATK Launch Systems – Promontory Facility, EPA I.D. #UTD009081357

Dear Mr. Gosen:

This letter is in reply to your correspondence, dated December 4, 2008, regarding the four issues that were identified during the Operation and Maintenance Inspection that was initiated
at the ATK Promontory facility on May 22, 2008. The Division’s response to ATK’s comments are as follows:

Issue #1:
Based on information provided by ATK, wells A-8, A-9, B-7 and C-4 are currently not operational since the dedicated pump for each well no longer works. Permit Condition IV.D.1.b states
that existing monitoring wells shall be maintained in a fully operational condition for the duration of the permit. Please identify how ATK plans to address this requirement. In addition,
please provide an evaluation of the condition of the screens for these wells.

ATK Response:
ATK acknowledges that some of the dedicated pumps are not operational. Wells A-9 and B-7 are operational. The dedicated pumping systems have been removed and the wells are open to sampling
using the approved Hydrasleeve. Wells A-8 and C-4 currently contain dedicated pumping systems that will be removed within the next year. This will satisfy the requirements of Condition
1V.D.1.b of the permit allowing the wells to be sampled and

thus operational per the permit. As of the last sampling event for each well, the screens in these wells were considered to be in good working order. No indication exists that would
suggest that the well screens are in disrepair.

Division Response:
Based on the removal of the inoperable pump systems from wells A-9 and B-7 and ATK’s plan to do the same at wells A-8 and C-4, it appears that ATK is working to comply with this permit
condition.

The Division originally asked that ATK provide an evaluation of the condition of the screens for these wells since corrosion of well screens has been a problem at the facility in the
past (e.g., Well B-6). Since ATK will be using the Hydra Sleeve sampler in these wells, it is important that the screens allow groundwater to flow freely through so that a representative
sample is collected. The Division recommends that ATK make an assessment of the screen with a down-hole camera when dedicated pumps are removed. Please submit the results of these
assessments to the Division when they are complete.

Issue #2:
Permit Condition IV.D.2.a. states that well construction shall follow the techniques described in the EPA TEGD. The TEGD recommends that monitoring well screens not exceed ten feet
in length. Based on the “Monitoring Well X-5 Installation Report,” Well X-5 was completed with a 20-foot well screen. Please explain why a 20-foot screen was used in Well X-5.

ATK Response:
Because the Promontory facility is located in a semi-arid environment, it was decided early in the drilling program to equip each well with 20-feet of screen to minimize the potential
for water levels to drop below the bottom of the screened interval and thus prolong the useful life of the well and minimize expenditures to re-drill if a well were to go dry. So long
as it made sense from a hydrogeologic standpoint to screen 20 feet of formation, (i,e., no screening across multiple aquifers) ATK standardized this approach for most monitoring wells.
It is worth noting that EPA’s scientific peer review of the TEGD, documented in the Report on the Review of the RCRA Ground-Water Monitoring Technical Enforcement Guidance Document,
Environmental Engineering Committee Science Advisory Board US Environmental Protection Agency June, 1986, stated that well screen length should not be limited to a maximum of 10 feet,
and recommended flexibility according to site hydrogeologic conditions. The November 1992 TEGD also indicates this flexibility on screen length, section 5.1.2., states “Generally, screen
length should not exceed 10 feet.”, and it then describes some of the conditions where a longer screen length is warranted.

Division response:
The Division agrees that, depending on hydrogeologic conditions, a 20-foot well screen may be appropriate. However, it is misleading to suggest that installing 20-foot screens is currently
the standard at ATK. It appears that Well X-5 is the only well that has been installed with a 20-foot screen since 1996. All of the G, H and J series wells installed since that time
are equipped with ten-foot screens.

Nevertheless, Post-Closure Permit Condition IV.D.2.b. states that “the Permittee shall construct and maintain new monitoring wells and piezometers in accordance with plans and specifications
to be submitted to the Executive Secretary for approval. The Executive Secretary will approve in writing the following: number, location, depth, and design of all new wells and piezometers
prior to installation.” The Division expects that monitoring well installation plans will be submitted for any new wells installed at the ATK facility.

Issue #3:
Based on available potentiometric surface data, it is unclear which direction groundwater is flowing in the extreme northeast area of the facility. It appears that groundwater elevation
drops from 4,372 feet at Well P-5 to 4,349 feet at Well P-1 indicating an easterly flow of groundwater in the area. In the past, ATK has shown on potentiometric surface maps that groundwater
flows in a southerly direction in this area. Since ATK will be collecting current potentometric surface data from the wells in this area this Fall. Please ensure that ATK evaluates
this issue after the data is collected.

ATK Response:
Water levels collected during the 2nd half of 2008 indicate that groundwater elevation at P-1 is at 4345 ft. and wells near P-1 (P-8 and P-9) have water levels at elevations of 4357
and 4355 ft.. Monitoring well P-5 is dry at an elevation of 4371. However, it appears that water at P-5 may be perched as the equivalent groundwater elevation is not repeated at nearby
wells. Generally speaking, groundwater flow in the northeast portion of the facility flows to the south.

Division response:
Based on the P-5 well log, it appears that the bottom of the well screen is at an elevation of approximately 4,360 feet. This elevation is inconsistent with ATK’s finding that the well
is dry at an elevation of 4,371 feet. Is it possible that some silting has occurred in the well? During the conference call held with ATK on December 16, 2008 to discuss these issues,
it was indicated that the potentiometric surface and condition of Well P-5 will be further evaluated by ATK. Please update the groundwater potentiometric surface maps in the Semi-Annual
Monitoring Report as needed.

Issue #4:
Significant contamination has been detected in Well J-4. Based on the concentrations of TCE that have been detected, it appears that the concentrated plume observed at Wells A-8, B-1
and E-9 down-gradient of the M-136 burn grounds may move in a southeasterly direction towards well J-4. It is apparent that more information is needed for this area. The Division and
ATK personnel have discussed installing an additional well to help define the extent of the contamination in the area. The Division is also aware that ATK has initiated a bore-scope
survey in the well to help determine the direction of groundwater flow. Please provide a proposal and schedule for evaluating the extent of contamination in this area.

ATK Response:
Results collected from the initial bore-scope survey at well J-4 were inconclusive. Therefore, another investigation is planned within the next few weeks to more closely examine the
zones where higher conductivity was indicated. Contamination at J-4 appears to be coming from an upgradient source (possibly the burning grounds). A soil gas study was performed in
August 2007 in the canyon area east of J-4. However, no contamination or source areas were indicated by the study. ATK is currently evaluating possible locations for an additional monitoring
well. A definitive bore-scope flow direction will play heavily in determining a location. Locations east of J-4 have been considered as have locations upgradient and north of J-4. It
is probably more important to determine where the contamination is coming from rather than where it is going. A potential suitable location for a new monitoring well would be northwest
of J-4. This well should be drilled to the regional aquifer with particular attention paid to any perched water encountered during drilling. Scheduling would require a bid specification,
proposal, and timeline from a qualified driller before a definitive schedule for the work can be conveyed to the Division.

Division response:
The Division agrees with ATK’s plan to conduct another investigation at Well J-4 with the bore scope, in order to determine the direction of groundwater flow at the well. In addition,
the Division agrees that it is important to determine the source of this contamination. However, if only one well will be installed, the Division believes it should be installed down-gradient
of Well J-4. Post-Closure Permit Condition IV.D.1.f. states that “if hazardous waste constituents exceeding the groundwater protection standard concentration limits, as defined in Section
IV.C. of this Module, are detected in the furthest down-gradient monitoring well(s), the Permittee shall install additional monitoring wells further down-gradient.”

ATK is scheduled to submit the human health risk assessment for groundwater contamination at the site by March 2, 2009. The extent of groundwater contamination in the area of Well J-4
hasn’t been determined. The Division considers this to be an
important data gap, particularly for the groundwater flow and transport models. We strongly recommend that ATK expedite the process needed to get the well installed.

This letter will serve to closeout the O&M Inspection. The Division will continue to work with ATK to address the groundwater contamination issues that exist at the facility. Thank
you for your cooperation. If you have any questions, please contact Jeff Vandel at 538-9413.

Sincerely,
ORIGINAL DOCUMENT SIGNED BY SCOTT T. ANDERSON FOR DENNIS R. DOWNS ON 12/29/08
Dennis R. Downs, Director
Utah Division of Solid and Hazardous Waste

DRD/JV/tjm

c: Paul Hancock, ATK Launch Systems
Lloyd Berentzen, Deputy Director, Bear River Health Department

File to: ATK Launch Systems - Promontory

December 29, 2008
Page 5
TN200801210

288 North 1460 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
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State of Utah

JON M. HUNTSMAN, JR.
Governor

GARY HERBERT
Lieutenant Governor

Department of Environmental Quality

William J. Sinclair
Acting Executive Director

DIVISION OF SOLID AND HAZARDOUS WASTE
Dennis R. Downs
Director