2004-10-26_REVISION - M1999002

• Permit No: M1999002
• IBM Index Class Name: Revision
• Doc Date: 10/26/2004
• Doc Name: Determination of Numeric Protection Levels and Early Warning Indicators.
• From: DMG
• To: American Soda LLP
• Type & Sequence: TR4
• Media Type: D
• Archive: No

STATIC OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources ,
1313 Sherman SL, Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
DIVISION O F
MIN SRALS
GEOLOGY
RECLAMATION•M INING
SAFETT•SCIENCE
Bill Owens
Governor
DATE: October 26, 2004 ~ Russell George
Executive Director
TO: Celina Akin, American Soda, LLP ~ Ronald W. Cottony
Division DirecYOr
I ~ Natural Resource Trustee
FROM: Allen Sorensol~ /
RE: Determination of Numeric Protection Levels and Early Warning Indicators, Yankee
Gulch Sodium Minerals Project, Technical Revision TR~ Permit No. M-1999-002 /
This memo provides an example of a Numeric Protection Level (NPI,) determination for boron in
monitoring we1121-3U at the Yankee Gulch Project. This example should be used to develop NPLs and
Early Warning Indicators (EWI) for all wells and parameters requiring such determinations as suggested
in American Soda's initial TR-04 submittal. In addition, DMG will require that American Soda continue
to analyze all collected ground water samples for major cations and anions, to complete a full suite
analysis in accordance with the original monitoring plan on one sample set per year, and to sample and
analyze process stream water quarterly For parameters listed in the original monitoring plan once solution
mining resumes. With regard to the once per year full suite analysis, the quarter during which this
analysis will be performed is as follows:
• First full suite analysis required for the fourth quarterly sample collected under the TR-04 plan.
• Second full suite analysis required for the seventh quarterly salmple collected under the TR-04
plan.
• Third full suite analysis required for the tenth quarterly sample collected under the TR-04 plan.
• Fourth full suite analysis required for the thirteenth quarterly sample collected under the TR-04
plan.
• On-going full suite analysis required for each third sample collected thereafter. This analytical
protocol will provide continuing information on seasonal inflrlences to ground water.
The baseline data set for boron in we1121-3U arranged in descending order and reported in mg/L is as
follows:
7 3.2 3.12 3 3 3 3 3 3 3 3 2.9 2.9 2.89 2.8
The presence or absence of statistical outliers is determined in accordance with the Dixon Test as
described in the attachment to this memo. For the baseline boron data from we1121-3U, the Dixon
calculation is as follows:
Q = (Xl - X2)i (Xl - xN) _ (~ - 3.2)i~~ - 2.8) = o.9os
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey