2014-10-22_PERMIT FILE - M2014043

• Permit No: M2014043
• IBM Index Class Name: Permit File
• Doc Date: 10/22/2014
• Doc Name: 112 Construction materials reclamation permit application preliminary adequacy review
• From: DRMS
• To: Albert Frei & Sons Inc.
• Email Name: TOD
• Media Type: D
• Archive: No

sd`k City of
ire Thornton
Infrastructure Maintenance Center infrastructure Department
12450 Washington Street 720-977-6600
Thornton,CO 80241-2405 FAX [phone]
www.cityofthornton.net
October 8, 2014
Mr. Tyler O'Donnell
Division of Reclamation, Mining and Safety RECEIVED
Department of Natural Resources OCT 14 2014
1313 Sherman Street, Room 215
Denver, CO 80203 DIVISION OF RECLAMATION
MINING AND SAFETY
RE: Frei Hatchery Pit - M.L.R.B. #M-2014-043
Dear Mr. O'Donnell:
The purpose of this letter is to file an objection to the issuance of a Reclamation
Permit on behalf of the City of Thornton (City) to the proposed mining and reclamation
operation at the Hatchery Pit (Pit) located in parts of the NE 1/4 SNW1/4, SE1I4
SW1/4, SW1/4 SW1/4, and NW1/4 NW1/4 of Section 20, T-2-S, R-67-W, 6th PM,
Adams County, Colorado.
The City's North Dahlia Reservoir and Dam (a.k.a. Tigers Reservoir and Dam) are
immediately adjacent to the proposed Pit. North Dahlia Reservoir has a capacity of
2,568 acre-feet and is a major component of the City's raw water infrastructure. The
City's reservoir is also lined by a soil-bentonite barrier wall below the dam. The Bull
Seep generally runs from south to north between North Dahlia Reservoir and the
proposed Pit. The City has constructed an existing drain system to manage flows
from the Bull Seep.
The associated excavations with the proposed Pit appear to be within a reasonable
proximity of the North Dahlia Dam. Currently the depth of the excavation, the location
of the top of the excavation, and the slope of the excavation is unknown. This
excavation could potentially adversely impact the stability of North Dahlia Dam or the
soil-bentonite barrier wall below the dam. The City requests that the applicant perform
an engineering evaluation to confirm that the proposed excavation will not adversely
impact the dam or the soil-bentonite barrier wall below the dam. The analyses should
include a drawing that defines the maximum western limit of excavation, the maximum
depth of excavation, the temporary and final slope angle of excavation, and the
calculations that demonstrate that the proposed Pit will not adversely impact the dam.
The analyses need to be submitted to both Thornton and the State Engineer's Office
(SEO), Dam Safety branch, for review and acceptance. The SEO needs to be
involved because there will likely be excavations within 200 feet of a jurisdictional
dam.
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