2014-08-05_HYDROLOGY - M1977344

• Permit No: M1977344
• IBM Index Class Name: Hydrology
• Doc Date: 8/5/2014
• Doc Name: Proposal to Remove Sodium as a Groundwater Quality Parameter
• From: ARCADIS
• To: DRMS
• Permit Index Doc Type: Hydrology Report
• Email Name: TC1
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St.,Room 215 C O L O RA D O
Denver,Colorado 80203 D S V I S I O N o f
RECLAMATION
Phone:[phone] MINING
FAX:[phone] _&—
SAFETY
November 27, 2012 John W.Hickenlooper
Governor
Mike King
Executive Director
Joe Lamanna Loretta E.Pineda
Holcim (US),Inc. Director
3500 Highway 120
Florence,CO 81226
Re: Portland Limestone Quarry, Permit No. M-1977-344, Revised Groundwater
Monitoring Plan
Mr. Lamanna:
The Division of Reclamation, Mining and Safety (DRMS) has reviewed your proposed standards
for MW-13 (reference Holcim letter to DRMS dated July 7, 2010). The data collected from MW-13
is intended to supplement data collected from MW-7. The DRMS approved numeric protection
levels (NPLs)for MW-7 on February 24, 2009,
The DRMS determines NPLs based on the five quarters of monitoring data initially collected from a
proposed monitoring well, not from nearby or upgradient wells. The selected NPL is typically the
larger of two values: 110 percent of the maximum concentration of a constituent of interest
observed during the five quarters of monitoring; or the mean observed concentration of the
constituent plus two standard deviations. Based on the five quarters of data provided by Holcim for
MW-13,the DRMS has determined the following NPLs are appropriate:
Parameter NPL for MW-13 Previously Approved NPL for MW-7
Total Dissolved Solids(TDS) 4,026 mg/C * 3,918 mg/C
Sulfate(SO4) 2,200 mg/C * 2,080 mg/C
Potassium(K) 13 mg/C. *$ 17 mg/f
Sodium(Na) 274 mg/C * 226 mg/C
Iron(Fe—dissolved) 0.13 mg/C $ 4.5 mg/C
Manganese(Mn-dissolved 0.30 mg/C $ 0.88 mg/C
* 110%of maximum observed value
$Mean observed value plus 2 standard deviations
Holcim will continue to monitor MW-12 (background) and MW-7 (west compliance well), and
provide results for the above parameters on an annual basis. When observed parameters in MW-7
and/or MW-13 (east compliance well) exceed the NPL by more than 10 percent, Holcim will
increase the monitoring frequency to semi-annually.
Office of Office of
Mined Land Reclamation Denver•Grand Junction•Durango Active and Inactive Mines