DSHW-2004-008287 - 0901a0688016081f

Paul Hancock, Manager
Environmental Remediation
ATK Thiokol Propulsion – Promontory
P.O. Box 707
Brigham City, UT 84302-0707

RE: 2004 Groundwater Monitoring at the ATK Thiokol Propulsion – Promontory Facility, EPA I.D. #UTD009081357

Dear Mr. Hancock:

This letter is in response to your correspondence dated March 29, 2004 regarding the sampling of groundwater monitoring wells for 2004. The Division of Solid and Hazardous Waste (the
Division) has reviewed the list of wells contained in your letter that Thiokol has proposed to sample this Spring and Fall. The list of proposed wells would provide a reasonably good
representation of groundwater conditions; however, Thiokol should consider the data that will be needed for the solute transport model that will be produced later this year. Nothing
is mentioned in your letter about the data requirements for the groundwater flow and transport models.

Ideally, samples should be collected during the same sampling event from all monitoring wells that will be used when calibrating the solute transport model so that data from close to
the same point in time will be available. It is understood, however, that the contaminant concentrations observed in some wells don’t change much over a one to two year period. On
the other hand, it has been observed that contaminant concentrations change significantly in that amount of time in other wells. The Division recommends that Thiokol discuss this issue
with its contractor that will be producing the model, and consider sampling all of the wells that will be used this Spring, or at a minimum, this year. In addition, potentiometric surface
data used in the model needs to be from the same sampling event.

The Division also requests that Thiokol sample the following wells and springs in addition to those proposed: the P-series wells (Spring), the H-series wells (Fall), the J-series wells
that are ready for sampling this Spring, Pipe Spring (Spring and Fall), Fish Spring, Horse Spring, and Shotgun Spring (Fall). The P-series wells are requested in order to provide more
sample results for the north area that hasn’t had much attention prior to the Spring of 2003. It is requested that the H-series wells be sampled in the Fall as well as Spring for the
same rationale. This also applies to any J-series wells that are ready to sample this Spring. Pipe Spring wasn’t included on the proposed list of wells and springs to sample. At a
minimum, the Division would like to see the main springs (Shotgun, Pipe, Fish and Horse) sampled semi-annually.

Please notify the Division once you have discussed data requirements for the groundwater flow and transport models with your contractor. Thank you for your cooperation. If you have
any questions regarding this letter, please contact Jeff Vandel at 538-9413.

Sincerely,

ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON 4/22/04

Dennis R. Downs, Executive Secretary
Utah Solid and Hazardous Waste Control Board

DRD\JV\ts

c: John C. Bailey, M.D., M.S.P.H., Health Officer/Director, Bear River Health Dept.
Linda Bowling, USEPA Region VIII

TN200400443
File to: ATK Thiokol Propulsion - Promontory

April 22, 2004
Page 2

State of Utah

Department of Environmental Quality

Dianne R. Nielson, Ph.D.
Executive Director

DIVISION OF SOLID & HAZARDOUS WASTE
Dennis R. Downs
Director

OLENE S. WALKER
Governor

GAYLE F. McKEACHNIE
Lieutenant Governor

April 22, 2004

288 North 1460 West • PO Box 144880 • Salt Lake City, UT 84114-4880 • phone [phone] • fax [phone]
T.D.D. [phone] • www.deq.utah.gov