2018-08-22_REVISION - M1977493A

• Permit No: M1977493A
• IBM Index Class Name: REVISION
• Doc Date: 8/22/2018
• Doc Name: Request for Technical Revision
• From: Climax Molybdenum
• To: DRMS
• Type & Sequence: TR28
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: Yes

Technical Revision (TR-28) Climax Molybdenum Company
Environmental Protection Plan Permit No. M-1977-493
As described above, and as listed in Table T-3, the sources of potential contamination in the Arkansas
River watershed include:
■ Impacted water from the flooded underground workings;
■ Run-off and seepage from the Storke Yard; and
■ Run-off and seepage from road cuts and overburden fill placement for road construction on
Ceresco Ridge above the Storke Yard.
With the reclamation completed at present, issues related to run-off and seepage have been significantly
reduced. There are no designated chemicals stored or utilized within the Arkansas River watershed.
T-5.1.2 Environmental Protection Facilities
The following controls are designated EPFs to prevent potential impacts to the Arkansas River Watershed
from Climax operations:
■ 5-Shaft Pump Station (and associated Storke Pipeline);
■ Storke Wastewater Pump Station; and
■ Ceresco Ridge Haul Road Fill Area Runoff Collection System.
5-Shaft Pump Station and Storke Pipeline: A pumping station installed in 5-Shaft maintains the water
level at an elevation that does not threaten the flow of impacted water to the Arkansas River Valley.
Storm water becomes impacted as it passes through the open pit area and collects in the underground
mine workings. The quantity of water entering the shaft fluctuates seasonally based on the amount of
runoff into the open pit area. Generally, minimum flows occur in the late fall through winter, increase as
early as April or May, and peak from mid-June through early August. The level of water in 5-Shaft must be
kept below the apex of the Mosquito Fault to prevent mine water from potentially impacting the Arkansas
River. The water level is maintained by pumping water through the Storke Pipeline to the ETDL and the
water treatment/process water circuit in the Tenmile Creek Watershed. As the mining of the open pit
advances in depth, the 5-Shaft Pump Station may become obsolete and pit water levels will be controlled
through other means.
Storke Wastewater Pump Station: The Storke Wastewater Pump Station is located just below the Storke
Yard and acts as a seepage and storm water collection and return system where collected impacted
water is pumped to the water treatment/process water circuit in the Tenmile Creek drainage. Two
concrete lined ponds at this EPF serve to collect seepage and storm water/snowmelt run-off from the yard
area and it is pumped to the ETDL where it mixes with other mine water prior to treatment.
Ceresco Ridge Haul Road Fill Area Runoff Collection System: Runoff from new fill material used to
improve the existing Ceresco ridge haul road remains within the 5-Shaft/Storke Wastewater capture area.
As indicated in TR-22, Climax constructed an additional runoff collection ditch below the fill placement
areas on Ceresco Ridge. The collection ditch intercepts and routes potentially impacted runoff to the
camp drainage system that reports to water treatment.
T-5.2 Eagle River Watershed
T-5.2.1 Potential Sources of Contamination
As listed in Table T-3, the sources of potential contamination in the upper watershed of the East Fork of
the Eagle River within the Climax property include:
■ 4 Dam seepage;
■ Robinson Dam seepage;
■ Tenmile Tunnel and 1 Dam seepage;
■ Robinson Lake (aka: Robinson Reservoir); and
EPP: Version R4 T-19 August 2018