REP00257

• Permit No: M1999002
• IBM Index Class Name: Report
• Doc Date: 6/23/2003
• Doc Name: Cavity Characterization Plan
• From: American Soda LLP
• To: DMG
• Media Type: D
• Archive: No

ASLLP Solution Mining Cavify Characterization Plan
During the past few years, American Soda LLP, (ASLLP) has been evaluating
options to fulfill the permit requirement of characterizing the size and shape of an
ASLLP nahcolite solution mining cavity. Through meetings with the BLM, EPA,
and DMG, the combination of using cross-hole seismic and cavity displacement
has emerged as the selected technique.
Well 29-24 (Figures 1 and 2) is on a growth trend which indicates it will be the
first well to achieve a 200 foot diameter cavity sometime in the fall of 2003. It is
anticipated that during the drilling schedule for 2003, a 300 foot offset well
adjacent to well 29-24 can"be drilled and completed. This well would be
completed but not placed into production. As Well 29-24 approaches the 200
feet mine plan diameter, 29-24 will be placed on standby and across-hole
seismic measurement will be performed. Upon completion of the seismic
measurements, the fluid from the cavity will be displaced with natural gas. As the
fluid is displaced, the volume of fluid displaced will be measured, the volume of
natural gas injected will be measured, and the intertace between the fluid and the
natural gas will be measured by temperature log. This will allow ASLLP to create
a cavity depth versus volume relationship. This relationship can be used in
conjunction with the cross-hole seismic to produce a representation of the cavity
• shape and size.
Cross-Hole Seismic Measurement and Modeling
The general procedure is as follows:
1. Well 29-24 will be placed on standby.
2. Wireline perforating charges will be lowered down the long tubing string on
well 29-24.
3. Twenty-three hydrophones will be lowered into an adjacent well 300'
away.
4. The perforating charges will be detonated and seismic signals will be
recorded by the hydrophones.
5. The process will be repeated to insure that sufficient information is
available to characterize the profile of the cavity wall between well 29-24
and the adjacent well.
In the Fall of 2002, Agapito Associates, Inc. (Agapito) contacted NSA
Engineering (NSA), of Golden, Colorado, for the purpose of proposing a method
for determining the size and shape of the cavern resulting from nahcolite
extraction.