2024-11-06_GENERAL DOCUMENTS - C1981028

• Permit No: C1981028
• IBM Index Class Name: General Documents
• Doc Date: 11/6/2024
• Doc Name: Proposed Decision and Findings of Compliance
• From: DRMS
• To: Coors Energy Company
• Type & Sequence: PR3
• Permit Index Doc Type: Findings
• Email Name: RDZ
• Email Name: AME
• Media Type: D
• Archive: No

Monitoring Wells
The table below summarizes well information. Elevations are top of casing elevations.
Well Elev. Aquifer Location
FPW 4780 Ennis Draw Mine
DH-96 4764 Ennis Draw Downstream from Mine
DH-122 4814 Ennis Draw Upstream from Mine
SMW-2 4803 Reclaimed Spoil Mine
AMW-1 4804 Undisturbed Overburden Downstream of B Pit
AMW-2 4811 Reclaimed Spoil Downstream of A Pit
Well sampling and water levels of subsurface water are taken from these six wells quarterly.
The sampling parameters are:
o Calcium - dissolved
o Iron - dissolved
o Magnesium - dissolved
o Manganese - dissolved
o Molybdenum - dissolved
o Sodium - dissolved
o Selenium - dissolved
o Lead - dissolved
o Hardness (as CaCO3)
o Alkalinity,total (as CaCO3 to pH 4.5)
o Carbonate (as CO3)
o Bicarbonate (as HCO3)
o pH (pH units)
o Specific conductance (mmhos/cm)
o Chloride
o Hydroxide (as OH-)
o Sulfate (SO4)
o Total dissolved solids (at 180 degrees C)
o SAR(sodium absorption ratio)
o Barium (added in 1998)
o Arsenic (added in 2000)
o Cadmium (added in 2000)
Keenesburg Strip Mine Page 11
October 2024 Findings for PR-03