PERMFILE63812

• Permit No: M2004067
• IBM Index Class Name: Permit File
• Doc Date: 9/14/2005
• Doc Name: 3rd Adequacy Response
• From: Banks and Gesso LLC
• To: DMG
• Media Type: D
• Archive: No

ENGINEERING SOLUTIONS FROM THE GROUND DOWN
14 September 2005
File No.105056-0O1
Banks and Gesso, LLC
720 Kipling St., Suite 117
Lakewood, CO 80215
Attention: Mr. Alex Schatz
Subject: Geotechnical Engineering Services
Proposed MMRR Quarry
Gilpin County, Colorado
Deaz Alex:
Reference is made to the letter from the State of Colorado Division of Minerals and Geology (DMG) dated
September 9, 2005. The DMG letter offered 4 different options for blasting vibration compliance plans. These
options were:
1. Maximum Peak Particle Velocity (PPV)
2. Scaled Distance Equation
3. Modred Scale Distance
4. Blasting Level Chazt
Lyman Henn proposes the MMRR Quazry use Option 4. Blasting Level Chart. Using this optioq the blasting
program at the MMRR Quany will use the Scaled Distance Formula for initial blasting. Preliminary
calculations indicate the maximum charge weight per 8 ms. delay period in pounds to be approximately 225
pounds at approximately 825 ft for Quarry Productioq 26 pounds at approximately 255 fr for Process Plant
Developmertt, and 22 pounds at approximately 235 ft for Access Road Developmem. These initial values for
the maximum charge weight will be used for initial blasting for these portions of the proposed MMRR Quarry.
The MMRR Quarry will monitor and evaluate every blast of this initial blasting program and will adjust the
maximum charge weight upwards in reasonable incremems, provided [he blast results are in compliance with the
Blasting Level Chart, to optimize the blasting program at the site.
Lyman Henn proposes the MMRR Quazry place a minimum of two seismographs [o monitor frequency and
peak particle velocity of each blast during the early stages of the blast development program and at least one
seismograph for every blast over the life of the quarry. The proposed seismograph locations, as shown on
Figure 1, are at the shortest distance from a blast to a critical s[mcture. For example, the distance from the
nearest Access Road Developmerd blast to Hwy 119 is estimated to be 235 ft. The distacee from the nearest
Product Processing Area to the Black Hawk Wastewater Treatment Plant is estimated to be approximately 435
ft. These two locations were chosen due to their relatively short distarrce [o blasting areas and therefore are
11016'h Street, Suite 900 -Denver, CO 80202-5202 -Tel: [phone] -Fax: [phone] - www.LVmanHenn.com
Geotechnical. Tunneling, and Construction Services