2015-10-06_PERMIT FILE - C1981019A ‎(3)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 10/6/2015
• Doc Name: Performance Standards
• Section_Exhibit Name: Volume 15 Rule 4
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
Plans for any modification of any sedimentation impoundments or dams will be submitted to the
Division, and no modification will begin until approval of the plans have been granted unless
such modification is necessary on an emergency basis for public health, safety or the environment
would be endangered.
Colowyo will inspect the condition of each pond quarterly (until a waiver for annual inspection is
granted) with the reports submitted quarterly as well. None of Colowyo's post -mining
impoundments will meet the size criteria of 30 CFR 77.216(a)(1989).
4.05.10 Underground Mine Entry and Access Discharges
Colowyo currently conducts surface coal mining exclusively.
4.05.11 Groundwater Protection
There are no aquifers or continuous sources of groundwater within the stratigraphic section from
which the Colowyo Mine mines coal using surface mining techniques. This is also noted in
Section 2.04.7. In addition, there are no continuous aquifers of regional extent within the entire
Williams Fork Formation in the location of the Colowyo Mine. Occasionally, a minimal amount
of water is found under perched conditions in noncontiguous lenticular sandstones and in
fractured coal under the sandstones. No toxic concentrations of acid-forming materials have been
found in the overburden, reclaimed slopes or surface and groundwater system associated with the
Colowyo Mine. No adverse effects on groundwater quality are expected to occur due to mine
excavations or backfilling.
4.05.12 Protection of Groundwater Recharge Capacity
The reclamation plan as described in 2.05.4 will return the disturbed lands to approximately the
pre -mining condition; therefore, groundwater recharge capacity is expected to approximate the
pre -mining condition. Also, because of the minimal existence of ground water in the mining area,
the mining operation and subsequent reclamation should have no adverse effect on the existing
groundwater recharge capacities.
4.05.13 Surface and Groundwater Monitoring
The proposed monitoring program will replace the existing monitoring program in it's entirety.
This section replaces Section 4.05.13 of Volume 12, as amended. Colowyo proposes monitoring
the following sites:
Sedimentation Ponds - The proposed surface water monitoring plan includes monitoring
required under the NPDES Permit Number CO -0045161 issued by the Colorado Department
of Public Health and Environment. Colowyo will measure the quantity and quality of any
discharges from the permit area in compliance with the NPDES Permit and in accordance
with permit requirements. Please refer to Colowyo's discharge permit for a list of monitored
parameters.
Colowyo will report the discharge in �,,ccordance with the Clean Water Act of 1977 under the
NPDES Permit on a quarterly basis; therefore, Colowyo will plan to use the NPDES report
for filing with the Division. All surface water and shallow groundwater monitoring data is
submitted in an annual report. Annual Hydrologic Reports for the period of January 15`
through December 31" will be submitted by April I" of the following year.
Collom — Rule 4, Page 12 Revision Date: 9/28/11
Revision No.: PR -03