2013-10-31_REVISION - M1977284 ‎(3)‎

• Permit No: M1977284
• IBM Index Class Name: REVISION
• Doc Date: 10/31/2013
• Doc Name: Drainage Design Plan Mineral Joe Mine
• From: Cotter
• To: DRMS
• Type & Sequence: AM1
• Email Name: TC1
• Email Name: SJM
• Media Type: D
• Archive: No

Mineral Joe Mine — Drainage Design Plan 10
3. HYDROLOGIC CHARACTERISTICS OF SITE SOILS
The dominant soil types in the Mineral Joe Mine facilities area are Bodot and Ustic Torriorthents, which
are shown as soil type 23 on Figure 4 of the EPP. Additionally, a thin exposure of rock outcrop — Orthents
complex has been mapped along the ridgeline (NRCS, 2012b) in the headwaters of Sub -basin 132. The thin
soils that occur on steeper areas of pinyon juniper woodlands in the vicinity of the Mineral Joe Mine (Unit
23) are classified as fine, montmorillonitic, calcareous, mesic Ustic Torriorthents and are mapped as
Hydrologic Soil Group C (Table 4). Rocky outcrop areas are mapped as Group D. These soil groups are
defined by the NRCS (2012a) as:
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly
of soils having a layer that impedes the downward movement of water or soils of
moderately fine texture or fine texture. These soils have a slow rate of water transmission.
Group D. Soils having a very slow infiltration rate (high runoffpotential) when thoroughly
wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a
high water table, soils that have a claypan or clay layer at or near the surface, and soils
that are shallow over nearly impervious material. These soils have a very slow rate of
water transmission.
Table 4. Soils Types in Vicinity of the Mineral Joe Mine Facilities (Sub -Basin B2)
Map
Hydro Depth
K Sat (micro
Soil Name Taxonomic Classification
Unit
Group (in)
m /sec)
Fine, montmorillonitic
0 -3
1.41 -4.23
Bodot, dry (calcareous), mesic Ustic
3 -30
0.42 -1.41
Torriorthents
30 -34
0 00 -14 11
23 C
Ustic 0 -4 1.41 -4.23
Torriorthents Ustic Torriorthents 4 -31 1.41 -4.23
31 -35 0.42 -1.41
Rock outcrop --- D 0 -60 0.00 -0.03
88 0 -1 14.11 -42.23
Orthents Orthents B 1 -14 14.11 -42.23
14 -24 1.40 -14.00
24 -60 1.40 -14.00
The runoff curve numbers for the site were selected based on soil type, land use, and vegetative cover. A
curve number of 73 was applied for pinyon - juniper with grass understory, in fair condition (30 -70%
vegetative cover) and group C soils (Table 5). A curve number of 89 was applied to areas occupied by the
gravel access road (County Road EE19). A curve number of 85 was applied to the disturbed ground and
waste rock piles in the mine facilities area. For sub - basins containing more than one soil or cover type, a
weighted average curve number was calculated based on the relative areas of each CN. Site curve numbers
are listed in Table 6 and area - weighted average curve numbers are provided in Attachment 4.
4148B.131029 Whetstone Associates