PERMFILE123411

• Permit No: M2004067
• IBM Index Class Name: Permit File
• Doc Date: 11/21/2005
• Doc Name: Exhibit 18
• From: Clear Creek District Water Providers LLC
• To: DMG
• Media Type: D
• Archive: No

Memorandum to Corey Hoffmann
November 14, 2005
• Page 12
engineering evaluations. Grounds for denial of this permit application by the Board
include whether "the application is incomplete:' C.R.S. § 34-32.5-115(4)(a).
As part of the Applicant's August 19, 2005, Response to 2"d Adequacy Review
comments, the Applicant submitted a report and blast analysis by Lyman Henn, Inc.
Consulting Engineers, This is the first time any evaluation of the blasting impacts had
been submitted. According to this report, Lyman Henn performed what it called a
"preliminary analysis" of anticipated peak particle velocities. In its 3`d Adequacy Review
comments, dated September 12, 2005, the Division found that the anticipated peak
particle velocity formula used by Lyman Henn is not acceptable to the Division as a
compliance option. Four alternate compliance options were presented by the Division.
In addition to the four options, the Division required the Applicant to conduct aPre-Blast
Survey of potentially affected structures (see Division's September 12, 2005, 3`d
Adequacy Review comments). Rule 1.1{48) defines "Structure, Significant, Valuable,
and Permanent Man-made" to mean "a nonportable improvement to real property which
has defined, current and recognizable value of an economic nature; generally including
but not limited to: buildings, houses, barns, fences, above or below ground utilities,
in•igation ditches, maintained or public roads, bridges, railroad tracks, cemeteries,
communication antennas, pipelines, water wells, water storage structures, discharge and
• conveyance structures, etc." The•pre-blast survey therefore includes building contents
and related appurtenances.
The Office of Surface Mining and Enforcement's (OSMRE) Blasting Guidance Manual
(1987) provides guidance on the conduct of pre-blast surveys. The Blasting Guidance
Manual in turn states that the "specific requirements of the pre-blasting survey are
included in Section 816.62 of the OSMRE regulations." As required by 30 CFR §
816.62(c), the operator shall determine the condition of the structures and shall document
other physical factors that could reasonably be affected by the blasting. Further, the
Blasting Guidance Manual states, "[TJhe survey must determine the condition of the
dwelling or structure and must document any pre-existing defects and other physical
factors that could reasonably be affected by the blasting." [Emphasis added].
Therefore the scope of any pre-blasting survey must include an evaluation of these
sensitive receptors as defined in both Rules and the Blasting Guidance Manual.
The facilities of the Black Hawk-Central City Sanitation District and the Silver Dollar
Metropolitan District represent sensitive receptors whose continuous operation is vital to
public health (wastewater treatment) and public safety (highway lighting). The City of
Black Hawk is obligated to respond to any emergency calls from the wastewater
treatment plant at potentially great expense. Therefore, it is critical that such a survey be
conducted. Further, in order to be reliable, the survey must be completed by a licensed
Professional Engineer, registered in the State of Colorado, who is familiar with the above
appurtenances and the potential impacts of external shock and vibration upon their
condition and operations.
•
LEONARD RICE ENGINEERS INC.
2000 Ctav STREET, SUITE 300, DENVER, COLORADO 8027 1-5I 1 9 • PHONE [phone] • Fnx (303) 45501 7 5