2014-05-29_HYDROLOGY - M1977342

• Permit No: M1977342
• IBM Index Class Name: Hydrology
• Doc Date: 5/29/2014
• Doc Name: 5-Quarter Water Quality Data and Baseline Parameters Report
• From: Climax
• To: DRMS
• Permit Index Doc Type: Hydrology Report
• Email Name: PSH
• Media Type: D
• Archive: No

CMC—Henderson Operations
5-Quarter Water Quality Data and Baseline Parameters Report
May 2014
condition of the steel casing and potential presence of bacterial activity, has been completed and an
adequate quantity of data are collected to generate statistically meaningful limits for these parameters.
With regard to manganese, data will be reviewed to determine whether the existing ambient NPL
developed for dissolved manganese in Establishing Background Threshold Values (BTV) for Manganese
(Gateway Enterprises, 2012), included as Appendix H to the GWMP, will sufficiently bracket conditions
at MLGW-ACR. The development of the NPLs will be consistent with established methodologies for
developing background threshold values. Proposed NPLs for MLGW-ACR are summarized in Table 3-1
' below.
Table 3-1: MLGW-ACR Numeric Protection Limits
Iron,dissolved NA(report)* NA
' Manganese,dissolved NA(report)* NA
Selenium,dissolved 0.05 Table 1,CBSG
IZinc,dissolved 5 Table 2,CBSG
pH,s.u. 5.9—8.5 Ambient
Sulfate 250 Table 2, CBSG
Notes:
Table 1,CBSG:Domestic Water Supply—Human Health Standards
1 Table 2,CBSG:Domestic Water Supply—Drinking Water Standards
*NPLs will be developed after an investigation to determine the source of elevated Fe and Mn in the well,
including the condition of the steel casing and potential presence of bacterial activity,has been completed and an
adequate quantity of data are collected to generate statistically meaningful limits for these parameters.
Ambient:pH-See Appendix C
3.2 MLGW-15
' 3.2.1 Monitoring Summary
As required by the GWMP, baseline monitoring was performed at MLGW-15 over a period of five (5)
calendar quarters from the 4th quarter of 2012 through the 4th quarter of 2013 for the parameters listed in
GWMP Tables 4-1 and 4-2.
' 3.2.2 Baseline Parameters Data Assessment
MLGW-15 monitoring data is summarized in Table B — MLGW-15 Monitoring Data. All results were
observed to be below the agricultural standards specified in Table 3 (refer to Appendix B) of the CBSG.
All five pH values were at or near the lower end of the CBSG Table 3 range of 6.5 — 8.5 standard units;
specifically values ranged from 6.5 to 6.8 standard units. A graph summarizing pH values at MLGW-15
' is presented in Figure 2. As mentioned, no other baseline monitoring parameter results exceeded
applicable CBSG standards nor were there any other apparent trends that were a cause for concern.
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