PERMFILE43804

• Permit No: m2004044
• IBM Index Class Name: Permit File
• Doc Date: 11/22/2004
• Doc Name: Adequacy Review Response
• From: Tetra Tech RMC
• To: DMG
• Media Type: D
• Archive: No

Mr. Larry Oehler
TETRA TECH RMC Adequacy Response M-2004-044
November 22, 2004
Page 4 of 20
will not accept the slopes you have proposed, without the construction of
facilities to retain runoff and sediment prior to reaching the ditches. The
Division does not believe that silt fences and hay bales will provide adequate
erosion control and protection of areas outside of affected lands from damage,
which could become a possible violation.
As shown on the attached plans, we have proposed a sediment collection trench to
be located at the toe of each slope for the West Fill Area. The sediment collection
trench is designed to collect stormwater from the area between the ditches that
will be used for excess fill material. The West Fill Area will be disturbed and fill
placed in stages. The sediment trench will be expanded as needed for phased fill
placement. The sediment collection trenches will be directed to settling ponds
located in each phase. Upon establishment of vegetation, the Swale and ponds
will no longer be necessary. The stages are identified on the Mining Plan Map
numbered I-6. Each stage will be filled to rough grade and be seeded with a
temporary cover crop. We have enclosed an Erosion Control Plan for the West
Fill Area.
Stockpiles in West fill area will not be greater than 30 feet high with 3:1
sideslopes. The topsoil grass screening berms will be graded with 4:1 sideslopes
as shown on the detail.
3. Will the existing topsoil in the Fill Area be salvaged before it is buried with
overburden, mud lens material and topsoil?
The existing topsoil in the Fill Area will be stripped and used to create the grass
covered screening berms along the northern property line. At final reclamation
the topsoil berms will be used for final grading the Fill Area.
4. On Page D-2 of your application you state "In addition, a portion of the Phase
3 topsoil and overburden will be removed to adjust the flood boundary....."
Please explain this statement and show, on an Exhibit C Map, the proposed
flood boundary adjustment.
The area of overburden and topsoil removal/floodplain adjustment could be the
west side of Phase 3 from the limit of floodway to the limit of mining excavation.
This material removal would shift the floodway to the west within the Aggregate
Industries property, allowing stockpile placement within the floodway in Phase 2.
This adjustment will need to be approved by Adams County and included in the
Floodplain Use permit. If through the Floodplain Use permit process, changes are
made to the mining and reclamation plans that affect the MLRB permit, a
technical revision will be submitted to the Division.
H:U919_019_01\MLRH\DMG Response\l st Adequacy Response to DMG 11-5-04.doc