2021-05-10_HYDROLOGY - M1977300

• Permit No: M1977300
• IBM Index Class Name: HYDROLOGY
• Doc Date: 5/10/2021
• Doc Name: Water Monitoring - Surface Water
• From: Colorado Legacy Land
• To: DRMS
• Email Name: AME
• Media Type: D
• Archive: No

COLORADO LEGACY LAND
12150 E.Briorwood Ave.,Suite#135,Centennial,CO 80112
T.[phone] m,1,e
May 4,2021
MAY 102021
Ms.Amy Eschberger
Colorado Division of Reclamation,Mining,and Safety DIVISION OF RECLAMATION
Department of Natural Resources MINING MD SAFETY
1313 Sherman Street,Room 215
Denver,CO 80203
Subject: First Quarter 2021 Sampling Results,
Schwartzwalder Mine,Golden Colorado,
Mine Land Reclamation Permit No.M-1977-300.
Dear Ms.Eschberger:
The first quarter sampling event at the Schwartzwalder Mine was conducted by Ensero Solutions US,Inc.
(Ensero)field staff on January 27 to January 29,2021.In addition to presenting sample data,CLL is including a
cross-section schematic to illustrate the Schwartzwalder mine pool elevation with respect to the elevation of
the Ralston Creek surface water sample locations. During the first quarter sampling event,all samples take of
Ralston Creek within the permit boundary were below the 30 µg/L. As shown in the attached schematic,given
that the elevations of surface water location ARH (SW-ARH)and FBRG(SW-FBRG)were above the elevation of
the mine pool at the time of sampling,the concentrations of uranium in Ralston Creek outside of the permit
boundary at SW-ARH and SW-FBRG and the downstream locations,SW-LLHG and SW-WEIR,are not tied to the
mine pool.In addition,the elevated water level in Monitoring Well 15 CMW-15)from fourth quarter 2020
shows a groundwater divide exists between the mine pool and Ralston Creek.
• Surface Water Data: There are thirteen quarterly surface water(SW)sampling locations.Figure 1
shows the location of each surface water sample locations along Ralston Creek.Table 2a summarizes
surface water field parameters.Table 2b summarizes the analytical data results.The analytical
laboratory data report and the chain of custody are attached to this report.A copy of the electronic
data deliverable(EDD)excel file for these samples are included in this submittal.
• Groundwater Data:There are thirteen quarterly groundwater monitoring well (MW) locations.Table
1 shows the monitoring well elevations.Figure 2 shows the location of each MW.Table 3a summarizes
groundwater field parameters. Table 3b summarizes the analytical data results. The analytical
laboratory data report and the chain of custody are attached to this report.A copy of the EDD excel file
for these samples are included in this submittal.
• Mine Pool Elevations:Table 4 summarizes the mine pool elevations for the quarter.Pumping of the
mine pool has consistently maintained the mine pool elevation below the regulatory limit of 150 feet
(ft)below the Steve Level even during months of no pumping.Maintaining the mine pool below the
regulatory limit has established a hydraulic gradient away from Ralston Creek,preventing mine water
from entering the creek in the permit area.
If you have any questions regarding this letter,please do not hesitate to contact me.
Sincerely,
y w.
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