PERMFILE115736

• Permit No: M2006003
• IBM Index Class Name: Permit File
• Doc Date: 5/12/2006
• Doc Name: 05/08/06 Groundwater Model Review Addendum 1
• From: Civil Resources LLC
• To: DMG
• Media Type: D
• Archive: No

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CIVIL RES"~U RCES, LLC
ENGINEERS Q PLANNERS
May 11, 2006
Mr. Tom Schreiner
Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, Colorado 80203
MAY f 22006
,pryisiea of Miperala aad Geology
RE: Hall-Irwin Corporation, Application No. M-2006.003 ~~
ParkerlDersham Sand and Gravel Resource; May 8, 2006 GroundwateF Model Review
Addendum 1
Dear Mr. Tom Schreiner: - -
Following is Civl Resources' (Hall-Irwin Consultant) response to your Adequacy Review dated May 8, 2006,
Groundwater Model Review, °Parker-Dersham Gravel Mine° Hall-Irwin Corporation File M-2006-003, Class: Permit
The applicant must commit to determination of a baseline water level (elevation) for each of the six
(6) piezometers, submittal of such data to DMG prior to exposure of groundwater at the site, and
keeping a record of these baseline elevations on site for comparison during all future water
monitoring, ie: personnel recording groundwater levels in the piezometers during future
monitoring will need to have the baseline elevation established and available for comparison at the
time of monitoring to determine if an exceedance (3' or greater difference) has occurred.
Hall-Irwin commits to determining a baseline water level for each of the six piezometers and has obtained
approximately 18 months of baseline groundwater data at the locations shown in the Groundwater Study.
These six piezometers will also be used to determine future groundwater elevations and will be measured
throughout the life of the mine unless otherwise approved by the DMG. Civil Resources has provided Hall-
Irwinwith acopy ofthe Groundwater Study and Hall-Irwin will be able to use the study as a tool for
comparing piezometer elevations.
The applicant must commit to submittal of each years water monitoring data and summary of
resultsldiscussion in each years Annual Report.
Hall-Irwin will submit a report generated by qualified personnel or consultants summarizing the
groundwater measurements and mining operations affecting the site and regional groundwater, i.e.
dewatering, slurry lining, recharging if necessary. The report will be generated annually and submitted to
DMG unless otherwise requested or required per a response to a trigger.
The applicant must commit to reporting an exceedance of a groundwater elevation (3' or more) to
DMG within 24 hours of recording such measurement, and submittal of a technical revision
indicating the mitigation method employed within 30 days of verifying a exceedance of a
groundwater elevation. (The applicant may also want to re-measure the groundwater elevation
within 24 hours to confirm that an exceedance has occurred, then notify DMG within 24 hours of
the confirmed exceedance).
451 OAK STREET, SUITE 209 • FREDERICK, COLORADO 80530 • PHONE: [phone] • FAX: [phone]