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 47
Attachment 1. Rip Rap Granular Bedding Specifications (from UDFCD 2011)
DRAINAGE CRITERIA MANUAL (V 1) MAJOR DRAINAGE
Table MDA I—Gradation for Granular SWiding
U S. Standard Sieve Sao
Percent Weight by Pass'
Square -Mesh Slaves
Type I CDOT Sw, 703,01
Type 11 CDOT Sw,
703,09 Class A
3 inches
Type 11
90-100
1% inches
4
—
11/4 inoes
—
20-90
inches
100
-----
#4
95-100
0-20
#16
45-80
#50
10-30
#100
2.10
#200
0-2
The Type I and Type II bedding specifications shown in Table MD -11 were developed using the T-V filter
criteria and the fact that bedding which will protect an underlying non-cohesive soil with a mean grain size
of 0.045 mm will protect anything finer. Since the T-V fitter criterion provides some latitude in establishing
bedding gradations, it is possible to make the Type I and Type 11 bedding specifications conform with
Colorado Division of Highways' aggregate specifications The Type I bedding in Table MD-11 is designed
to be the lower layer in a two-layer filter for protecting fine-grained soils and has a gradation identical to
Colorado Department of Transportation's (CDO'rs) concrete sand specification AASHTO M-6 (CDOT
Section 703.01). Type 11 bedding, the upper layer in a two-layer filter, is equivalent to Colorado Division
of Highways! Class A filter material (Section 703,09 Class A) except that it permits a slightly larger
maximum rock fraction When the chary* is excavated in coarse sand and gravel (50% or more of
coarse sand and gravel retained on the #40 sieve by weight), only the Type It filter is required.
Otherwise, a two-layer bedding (Type I topped by Type 11) is required. Alternatively, a single 12-inch layer
of Type 11 bedding can be used, except at drop structures For required bedding thickness, see Table
MD -12, At drop structures, a combination of filter fabnc and Type 11 bedding is acceptabile as an
alternative to a two-layer fitter
Table MD-12—Thicknesils Requirements, for Granular Bedding
Riprap Designation
g ess (inches)
g Thi
Minimum Bedding Thickness g
Fine-Grained Soils'
Coarse-Grained Solis—
Type I
Type 11
Type 11
VL (dw = 6 in), L (dw = 9 in)
4
4
M (dw = 12 in)
4
4
H (4dso = 18 in)
4
6
(d.= 24 in)
4
6
May substitute one 12-inch layer of Type 11 bedding. The substitution of one layer of Type 11 bedding shall not
be permitted at drop structures, The use of a con-bnation of idler fabric and Type 11 bedding at drop structures
is acceptabic
Fifty percent or mare by weight retained on the # 40 sieve
Rev 042008
Urban Drainage and Flood Contlof Distract
URI%
4148B.131029 Whetstone Associates 4