GENERAL45818

• Permit No: M1999002
• IBM Index Class Name: General Documents
• Doc Date: 5/4/2004
• Doc Name: Well 20-74 and Temporary Cessation Status
• From: DMG
• To: American Soda LLP
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: (303) 86fr3567
FAX: [phone]
May 4, 2004 ~
Mr. Ed Cooley
American Soda, LLP
2717 County Road 215
Pazachute, CO 81635
RE: American Soda, LLP, Yankee Gulch Minerals Project, Permit No. M-1999-002
We1120-74 and Temporary Cessation Status
Deaz Mr. Cooley,
COLORADO
DIVISION OF
MIN&RALS
GEOLOGY
RECLANATION•MINING
rAf FTY•5<IENCf
Bill Owens
Governor
Russell Geolge
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
This letter is to clarify your questions regazding We1120-74 and provide guidance for American Soda to
transition the Yankee Gulch Mine into Temporary Cessation (TC) status.
weu 2a~a
During the meeting on Apri122, 2004 between American Soda, DMG, EPA and BLM, American Soda
requested that We1120-74 be increased an additional 10 feet in diameter for a total diameter of 220 feet.
Well 20-74 is surrounded by two other active wells to the north and south a[ a distance of 3001ineaz feet
(wells 20-31 and 20-33). We1120-31 has been mined to a diameter of approximately 139 feet and well
20-33 has been mined to a diameter of approximately 143 feet. To the west, We1120-32 maintains a
distance of 600 linear feet. The 112 permit does address spacing between adjacent cavities at a
minimum intact pillaz width of 50 feet between adjacent cavities to prevent cross communication of the
mining fluids and cavity collapse in the direction of the dissolution surface.
It is the Division's understanding that wells 20-31 and 20-33 will continue to be mined until July 1,
2004, but will not increase substantially in size due to the phasing down of the operation. With the
additional 10 feet, the pillar spacing between wells 20-74 and 20-31 will be maintained at approximately
122 feet and the spacing between wells 20-74 and 20-33 will be approximately 123.5 feet. The
diameters provided by American Soda aze determined by volumes removed using the assumption that
the cavities have developed as uniform cylinders. Dissolution of rich beds of nahcolite could result in
non-uniform cavity shape where diameters in limited horizons could be substantially lazger than those
provided by the company. That is why the permit requires cavity chazacterization prior to infilling close
spaced wells in the mining pattern. The current well spacing prior to cavity chazacterization is
conservative to approve adding another 10 feet in diameter to 20-74 at this time. However, any
additional increase in diameters on well on 300 foot spacing will require results from the cavity
characterization study.
Temporary Abandonment of Production Wells and Temnorarv Cessation (TCl Status
American Soda informed the Division Uhat the Piceance Operations will be phased down starting July 1,
2004 and the facility and well field will be mothballed. American Soda is in the process of developing
the necessary plans and making required procedural changes to ensure that the temporary cessation of
the facilities will comply with all federal, state, and local regulations. American Soda intends to
maintain the status of permits, leases and bonding requirements so that operations can be re-established
at any time in the future.
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey