2014-12-15_PERMIT FILE - M2014043 ‎(2)‎

• Permit No: M2014043
• IBM Index Class Name: Permit File
• Doc Date: 12/15/2014
• Doc Name: Preliminary Adequacy Review Response #2.
• From: Environment, Inc.
• To: DRMS
• Email Name: TOD
• Media Type: D
• Archive: No

MINING PLAN EXHIBIT D(CONT)
erosion and redeposition of rock materials from the front range
of the Rocky Mountains . The deposition of this material occurred
during a time when the river was much larger than it is now.
According to the USGS Geologic maps for this area the material
underlying the gravel to be mined is a part of the Denver
Formation. It is a dense, grey shale, silty claystone and
interbedded siltstone formation of the Upper Cretaceous age that
is from 800 to 1000 feet thick.
This type of material is typically found from south of Denver to
the Colorado state line along the South Platte River. Along this
section of the river, the deposit has a 60% rock, 40% sand ratio
and averages 30 feet deep.
There are two zones of gravel on this property, The upper or
terrace deposit along the eastern half of the permit area and the
alluvial gravels lying on the western part of the site. The
upper 30+ feet of the terrace deposit is dry while the lower 15+
feet are below groundwater due to what we believe is a ridge of
shale running north/south or parallel to the base of the
escarpment that divides the site. This ridge impedes the flow of
groundwater from the east to west until it reaches 5072 and
overtops the ridge. Drilling data provided by the landowners
show the shale bedrock rises to within 3 feet of the surface in
the area between the base of the hillside and the old lake or
approximately where we placed the Stage Line separating the two
stages . The ditch constructed by past owners along this line
collects the water and diverts it to the old hatchery area.
SOILS AND OVERBURDEN
See the soils and vegetation information in EXHIBITIM for detailed
information regarding the soils on this site. The soil
information is not site specific, it describes in general terms
the nature of the soils found at this site and was obtained from
the USDA soil survey for Adams County.
Approximately 3 . 17 acres of this site is covered by structures
and associated parking and driveways where there is little soil
in and around them. Of the remaining 50 . 00 acres, 10 . 15 acres is
pre-law mining area, 1 .24 acres is abandoned fish rearing
raceways, 0 . 38 acres is the Bull Seep and associated water ways
on the west side of the property. Overlying the gravel deposit
on the rest of the area is a layer of soil/ overburden that
5 (Revised 12/15/2014)