PERMFILE47013

• Permit No: M2006073
• IBM Index Class Name: Permit File
• Doc Date: 4/4/2007
• Doc Name: Adequacy Response 2
• From: Banks and Gesso, LLC
• To: DRMS
• Media Type: D
• Archive: No

ENGINEERING SOLUTIONS FROM THE GROUND DOWN
April 3, 2007
File No. 107009-000
Banks and Gesso, LLC
720 Kipling Street, Suite 117
Lakewood, Colorado 80215
Attention: Alex Schatz
Subject: Slope Stability Analysis
Sundance Sand and Gravel Resource
EI Paso County, Colorado
Mr. Schatz:
Lyman Henn, Inc. (Lyman Henn) is pleased to present Banks and Gesso, LLC (Banks and Gesso) with the results
of a slope stability evaluation of the excavation slopes at the proposed Sundance Gravel Pit, an alluvial deposit
located within the floodplain of Fountain Creek. Figure 1 shows the project location. The site is proposed as a
construction materials aggregate mine and will be mined in two phases. Lyman Henn performed this evaluation to
determine a recommended setback between the proposed gravel mine excavation slopes/highwalls and adjacent
structures. The slope stability analyses were performed using: 1) existing information from the site vicinity
provided by Banks and Gesso; 2) conservative assumptions for material strengths for the natural soil materials in
the proposed cut slopes; 3) expected groundwater conditions; and 4) Lyman Henn's understanding of the
proposed mining plan.
SITE DESCRIPTION
The proposed mining plan consists of three mining areas separated by native soils. The site is located within
parts of the E'h of Section 9, the SW '/a of Section 10, the NW'/a, SW '/a, and the SE'/a of Section 14, the NW 1/s,
NE'/a, and the SE'/a of Section 15, the NE t/a of the NE'/a of Section 22 and the NW'/a of Section 23, all in
Township 17 South, Range 65 west, 6s' P.M, El Paso County, Colorado. The western boundary of the site abuts
Union Pacific Railroad (UPRR) and the eastern boundary abuts Fountain Creek. A buried fiber optic line and
overhead utility run pazallel to the UPRR. Barn structures exist [o the west and south of the permit boundary.
Local service electric utility poles run east to west through the middle of the site, dividing Phase 1 and Phase 2 of
the mining plan. High tension electrical transmission lines mn east to west in the southern portion of the site,
dividing Phase IIA and Phase TIB of the mining plan. The specific adjacent features addressed by [his evaluation
as shown on Figure 2 aze: the local electric service utility poles in the, the high tension electric transmission, the
UPRR and fiber optic line, and the existing barn structures. Existing grade at the site slopes gradually up from
southeast to northwest at an average grade of approximately 0.6 percent from el. 5250 to 5300. Future temporary
overburden stockpiles of up to 40 ft with 2H:1 V (horizontal:vertical) side slopes aze planned along the western
boundary of the site.
110 16th Street, Suite 900 -Denver, CO 80202-5202 -Tel: [phone] -Fax: [phone] - vvww.LymanHenn.com
Geotechnical,Tunneling and Construction Services