2023-05-17_PERMIT FILE - M2021052

• Permit No: M2021052
• IBM Index Class Name: Permit File
• Doc Date: 5/17/2023
• Doc Name: Adequacy Review Response
• From: IHC Scott
• To: DRMS
• Email Name: ACY
• Email Name: THM
• Media Type: D
• Archive: No

Rifle Gravel Pit#1 May 2023
Table 2.Estimated Timetable for Phases 1-4 Activities
Phase/Stage Estimated Duration Estimated Depth Estimated Estimated Type of
Earthwork Area Acres Earthwork Volume CY Overburden
Total area=11.18 acres Total overburden=54,111 CY
30"cut=42,267 CY
6"topsoil=11,844 CY
Berm area=2.87 acres Berth overburden=11,528 CY
Berth topsoil=2,305 CY topsoil Clay and silt;about
Phase 1 1-2 months to 1-foot of
Site Development&Grading June—July 2023 Approx.0.5 feet to 1 fool Excess overburden area(temporary)=varies acres Excess overburden for sale post-bens construction(secondary commodity) topsoil,medium
=30,423 CY still,slightly moist,
Excess topsoil area(temporary)=varies acres brown
Excess topsoil for post-mining reclamation and sale(estimate)=9,539 CY
Topsoil to be kept for post-mining reclamation=566 CY(will be tarped)
Topsoil that can be sold=8,974 CY
Operations Pad=1.86 acres 2,999 CY Class 6
1-2 months No additional
Phase 2 August—September N/A overburden will be
Mining Preparation 2023 removed during this
phase.
Phase 3 3-5 years 10.43 acres 292,810 CY
Mining Extraction Sept 2023—Dec.2026 17—21 feet Varies
to Dec.2028
The estimated area to be mined(processed and stockpiled)at 30%is The estimated amount of material mined and processed at 30%=88,000 See Boring 4
approximately 4.78 acres CY Remove estimated
21 feet 6"of clay and silt;
30% 1—1.5 years (gravel layer thickness) gravel layer
estimated at 1 foot
to 22 feet below
surface.
Cumulative area estimated at 60%=6.83 acres Cumulative volume of material mined and processed at 60%=140,000 CY See Boring 3.
Remove estimated
5.5 feet to 6 feet of
60% 1—1.5 years 21 feet clay and silt
(gravel layer thickness) Estimated area mined and processed between 30%and 60%=2.05 acres Estimated volume of material mined and processed between 30%and 60% overburden;gravel
=52,000 CY layer estimated at 7
feet to 27 feet
below surface.
Cumulative area estimated at 100%=10.43 acres Cumulative volume of material mined and processed at 100%=292,810 See Boring 3.
CY Remove estimated
Estimated area mined and processed between 60%and 100%=3.60 acres 5.5 feet to 6 feet of
100% 1—1.5 years 21 feet Estimated volume of material mined and processed between 60%and clay and silt
(gravel layer thickness) 100%=152.810 CY overburden;gravel
layer estimated at 7
feet to 27 feet
below surface.
Berm Reclamation from Phase 1=2.87 acres Berth reclamation completed in Phase 1
Welland Reclamation fringe=0.7 acres Wetland reclamation to be completed using topsoil retained as part of
Phase 1=566 CY,surface the wetland fringe to a depth of 6"
Phase 4 6 months NA Reclaimed Pond Surface Area=9.55 acres NA
(Final Reclamation) December 2026-2028 Upland Buffer Area is not expected to require active reclamation due to
Upland Buffer Area=4.02 acres lack of surface disturbance.Incidental seeding and/or weed treatment only.
Operations Pad to be maintained as storage=1.86 acres Operations Pad will remain as Class 6 road base applied in Phase 2,and
maintained for use in Scott's regional operation
'The depths and thicknesses are estimated and based upon the nearest exploratory bodng logs included in Attachment C.
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