PERMFILE57167

• Permit No: M2002078
• IBM Index Class Name: Permit File
• Doc Date: 10/1/2002
• Doc Name: Adequacy Letter
• From: DMG
• To: Coulson Excavating Company Inc.
• Media Type: D
• Archive: No

4. The applicant mentions that a hydraulic modeling study was performed by WSI in the azea of the Stroh
Pit and the results show the floodway of the Big Thompson River encroaches into parts of the pit in the
northem section. Please provide a revised copy of Exhibit C-Mining Plan Map to show the boundaries of
the "floodway" of the Big Thompson Rivet In the absence of such information, the applicant may be
required to maintain a setback of at least 400 feet from the south bank of the Big Thompson River.
5. The applicant mentions that mining in the north zone of the Stroh Pit will be restricted to the period of
October 15 [o April 15 and that prior to April 15 of each mining year, all of the north zone will be
backfilled to original ground surface elevations. The purpose of this restriction is to protect the pit from
being captured by the river during seasonal flooding and to prevent the take of PMJM (Preble's meadow
jumping mouse) due to mining activity. In response, the Division will require that each year the mining
and reclamation permit for the Stroh Pit is active, the operator will submit a signed affidavit to the Division
of Minerals and Geology on or before April 15 which states that all of the north zone has been backfilled
to original ground surface elevations. Please confirm.
6. The applicant mentions that each cell will have a vertical depth of 25 feet and will be graded at 1:1.
Please clarify whether mining will occur at a 1:1 slope. If not, the Division will anticipate 0.5:1 pit slopes
in need of backfilling and grading during final reclamation. Please respond.
6.4.5 EXHHiIT E -Reclamation Plan
7. The applicant indicates that there will be a total of 1,184,559 cubic yazds of overburden generated
during the life of mine at the Stroh Pit (966,469 cubic yazds from the south cell and 15,578 cubic yards
from the north cell). In conformance with Rule 6.4.5(2)(d), please verify that all 1,184,559 cubic yazds of
overburden produced will be backfilled on-site during reclamation and indicate the maximum volume of
overburden that will be stockpiled at any one time throughout the operation.
8. The applicant mentions that backfilling will create a slope of approximately 2:1 that will become the
pond wall slope. In conformance with Rule 3.1.5(7), pond slopes shall be no steeper than a ratio of 2:1,
except from 5 feet above to 10 feet below the expected water line where slopes shall no[ be steeper than
3:1. Please respond with the elevation of the expected water line and slope configuration for each pond.
9. The applicant mentions that approximately 34,688 cubic yazds of topsoil will be replaced along the
perimeters of the ponds at a maximum depth of approximately 0.5 feet. The applicant mentions in Exhibit
I -Soils Information that the average topsoil depth over the permit area is approximately 1.93 feet, and
that the northem and southern mining zones contain a total of approximately 220,974 cubic yazds of
topsoil which will be removed and stockpiled and then re-spread during reclamation. Because 63 acres of
the affected land will be reclaimed to water surface, there will be an abundance of topsoil available for
reclamation. The Division requests that the applicant commit to a minimum topsoil replacement depth of 2
fee[ for all areas to be topsoiled and revegetated. Please confirm and verify the total acreage to be
topsoiled and revegetated.
6.4.6 EXHBIT F -Reclamation Plan Map
10. In conformance with Rule 6.2.1(2)(b) please revise the reclamation plan map to demonstrate that i[ has
been prepazed and signed by a registered land surveyor, professional engineer, or other qualified person.