2018-09-04_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 9/4/2018
• Doc Name: Volume 1 Rule 4
• Section_Exhibit Name: 4.01 Throuugh 4.30
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
In an effort to overcome these limitations, the Division of Minerals and Geology (DMG) requested
Colorado State University (CSU) to assist with a study plan to evaluate shrub establishment. A
study design was developed after considerable discussion with representatives from the mining
community, the DMG and the Colorado Division of Wildlife (DOW). Three coal mines in
northwestern Colorado volunteered to assist with the project by providing personnel, regraded
lands for the plots, construction equipment, planting materials, elk proof fencing, and plot
maintenance. At each mine demonstration plots were constructed in the fall of 2000. Five to six
treatments were established to evaluate shrub establishment techniques that have commercial
practicality on a large scale. The specifics of the Colowyo demonstration plots are found in the
Colowyo Mine Specific Field Trial section of this narrative.
The study design took into consideration the possible limitations to shrub establishment. The
treatments vary at each mine to accommodate the reclamation techniques and material availability
for each site, but certain similar treatments were included at each mine. To evaluate effect of the
herbaceous competition, seed mixes were designed so that shrubs contributed the majority of the
seed mix. Two seed mixes were evaluated at each mine:
• a native grass, forb and shrub seed mixture and
• a seed mixture of unpalatable native shrubs and low -competitive native grasses and forbs.
At each mine, one treatment included alternating strips seeded with only the shrub/forb component
of the mix. At Seneca Mine, treatments included seedling transplants, for tall shrub species that
have proven to be particularly difficult to establish from seed.
Typical topsoil replacement depths varying from 12 — 20 inches creates an ideal environment for
grass establishment. Therefore, the depth of topsoil on the plots was varied to evaluate shrub and
forb response to topsoil depths ranging from 0 to 20 inches.
Composite soil and overburden samples were taken from each treatment at each mine. Overall,
the soils (topsoil and spoil) at all three -mine sites have good physical and chemical properties.
Soil pH ranges from 6.9 to 7.8, macronutrients appear to be adequate for sustained plant growth,
organic matter contents are relatively high (3.7% to 6.3%), salt levels are low (EC ranges from 0.6
to 1.6 mmhos/cm and SAR ranges from 0.3 to 1.8), cation exchange capacity (CEC) is in a normal
range, and textures are clay loam and sandy clay loam. Overall, topsoil and spoil at all mine sites
have favorable characteristics and provide a suitable plant growth medium.
At Colowyo, soil pH ranges from 7.5 to 7.8, macronutrients appear to be adequate for sustained
plant growth, organic matter contents are relatively high (3.7% to 4.8%), salt levels are low (EC
ranges from 0.6 to 1.2 mmhos/cm and SAR ranges from 0.3 to 1.6), cation exchange capacity
(CEC) is in a normal range, and textures are clay loam and sandy clay loam. The detailed soil and
overburden analysis for the Colowyo Mine is provided below.
Parameter
pH
% OM
NH4-N mg/kg
Plot 18
Plot 2b
7.5
7.5
4.1
4
4.9
4.6
Plot 31
Plot 4d
Plot 5e
7.5
7.7
7.8
4.8
4.1
3.7
6
6.1
8.7
Rule 4 Performance Standards 4-51 Revision Date: 5/25/18
Revision No.: RN -07