2018-04-13_PERMIT FILE - C1981019A

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 4/13/2018
• Doc Name: Volume 1 Rule 4
• Section_Exhibit Name: 4.02 Throuugh 4.30
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
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
Plot 18 Plot 2b
Plot 31
Plot 4°
Plot 5e
pH
7.5 7.5
7.5
7.7
7.8
% OM
4.1 4
4.8
4.1
3.7
NH4-N mg/kg
4.9 4.6
6
6.1
8.7
NO3-N mg/kg
24.1 19.1
22.3
13.7
18.1
P mg/kg
15 9.6
12
7.8
29
K mg/kg
191 210
201
95.1
105
Ca meq/L
4.9 4.1
4.4
3.5
5.5
Mg meq/L
2.6 1.6
2
2.4
4.1
Na meq/L
0.8 0.6
1.3
1.9
3.5
K meq/L
0.2 0.5
0.4
0.2
0.2
EC mmhos/cm
0.7 0.6
0.7
0.7
1.2
SAR
0.4 0.3
0.8
1.1
1.6
CEC meq/100g
26.8 22.1
22.9
27
23.3
% Sand
41 51
48
39
41
% Silt
23 23
23
23
25
% Clay
36 26
29
35
35
Texture
clay loam sandy clay loam sandy clay loam
clay loam
clay loam
aPlot 1 = 18 inches of
topsoil, strip seeding in alternate rows.
bplot 2 = 6 inches of
topsoil and surface manipulation, seeded with native
shrubs and low competitive
forbs.
'Plot 3 = 6 inches of topsoil, strip seeding in alternate rows.
'Plot 4 = Non-topsoiled
spoil, strip seeding in alternate rows.
'Plot 5 = Non-topsoiled
spoil, seeded with unpalatable native
shrubs and low competitive forbs and
grasses.
To evaluate the impact from wildlife browsing, elk proof fencing was constructed on one-half of each
treatment.
Rule 4 Performance Standards 4-45 Revision Date: 4/10/18
Revision No.: MR -184