GENERAL35570

• Permit No: M1999002
• IBM Index Class Name: General Documents
• Doc Date: 2/14/2005
• Doc Name: Major Mod. UIC Area Permit No. CO30858-00000
• From: EPA
• To: American Soda LLP
• Media Type: D
• Archive: No

3. Monitoring Devices
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Cavity development .....
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(2nd pazagraph) The applicant has prepazed the Subsidence Monitoring Plan dated
August 2004, which was submitted to the BLM, Colorado Division of Minerals
and Geology (CDMG) and the EPA. This plan is incorporated into this Permit as
Appendix J. As provided in this plan, the permittee shall establish surface
monitoring monuments on well casings and well pads in addition to establishing
land surface monuments at certain section and quarter section corners. The
subsurface monitoring plan includes the test installation of coaxial cable in
solution mining we1120-12 bore for use of Time Domain Reflectometry (TDR), to
detect differential movement close to the top of the cavity and above. If
subsurface movement occurs, the coaxial cable will break or stretch. The location
of the change in coaxial cable properties will be determined by use of a cable
tester. Borehole geophysical logs will be run twice for each well in service during
the life of a well: (1) following initial drilling of the well and (2) after retirement
of the well. Corrective action will be implemented if necessary. The Director
may also require changes in the operating plan for new cavities, such as a lazger
pillaz between individual cavities. The shape of the cavity is, of course, an
important element that affects subsidence. For that reason, the permittee has
evaluated techniques for and undertaken studies to assess cavity shape.
Depending on the results of these studies, American Soda may be required to
establish additional monitoring wells to better track cavity influence on the pillars.
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(4`" paragraph) The injection fluid and production fluid ninelines shall be
equipped with samplingports to facilitate periodic collection of samples for
chemical analysis. Injection fluid samples shall be collected from the pipeline
upstream of where the pipeline branches to feed all solution mining wells.
Production fluid shall be sampled on the production trunk pipeline prior to
entering a gas sepazator. Samples of both the production and the injection fluid
shall be collected and analyzed according to the Ground Water. Surface Water.
and Process Monitoring Plan (the Water Monitoring Plan), Appendix I.
(5`" pazagraph) Monitoring of water quality and water level shall occur
according to the Water Monitoring Plan, Appendix I. The Pennittee has aheady
collected five (5) quarters of baseline data, prior to the commencement of
operations, for the Alluvial Aquifer, the Upper Aquifer (A-Groove and Uinta
Formation), and the Lower Aquifer (B-Groove and Dissolution Surface).
Additional monitoring wells maybe deleted or added to the monitoring program,
if necessary, as development of the commercial solution mining well field
Draft Modification No. 9 UIC Area Pernut No. CO30858-00000 Page 7 of 44