PERMFILE67353

• Permit No: C1981022
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 2.06 Requirements for Permits for Special Categories of Mining
• Media Type: D
• Archive: No

S~iae - 2.06.8
2.06.8 -Surface Coal Mining and Reclamation Operations on Areas, or Adjacent to
Areas, Including Alluvial Valley Floors
By regulatory definition, an Alluvial Valley Floor (AVF) u an azea of unconsohdated stream-laid
deposit holding streams with water availability sufficient for sub-imgation or flood irrigation
agricultural activities. The initial step in detemuning whether or not an area qualifies as an AVF u
confirmation of the presence of alluvial deposits. To qualify, the alluvial deposiu must be located in a
valley floor area. Isolated elevated terraces and areas overlain by a thin veneer of colluvial deposiu
composed of debris from sheet erosion, deposits from un-concentrated runoff or slope wash, talus
materials, or mass movement or windblown deposits do not qualify. If the presence of qualifying
valley floor alluvial deposiu is indicated or confimred, then the existence of or capability to support
flood imgated or sub-irrigated agricultural activities is evaluated. This evaluation includes
consideration of water availability, water quality, soils, topography, and regional practices. An
additional limitation relative to designation as an AVF u the minimum size criteria of 10 acres.
A reconnaissance level AVF investigation was conduced in May 1981. Initially, 1«ations where
unconsolidated streartrlaid deposiu might exist were identified by reviewing the previous maps used
to develop Map 2.04-M2, Regional Geology/Hydrology. Field investigations of the identified
potential AVF areas were then conducted to evaluate site-specific conditioris. The areas investigated
included portions of the Elk, Bear, and Hubbard Creek drainages and an area along the north side of
the North Fork of the Gunnison River (bounded on the east by the intersection of the east line of
Section 12, T13S, R90W and on the west by the west line of Section 14, T13S, R91W). The Elk, Beaz,
and Hubbard Cmek drainages are upland tributaries to the North Fork The ass«iated drainage
valleys are generally narrow with moderate to steep gradienu and steep sideslopes and the limited
alluvial deposiu that do exist are confined to a narrow band within and immediately adjacent to the
stream channels. Generally, areas of contiguous alluvial deposits are less than 10 acres and both the
• elongated configuration of these deposits and the steep terrain would preclude effective agricultural
utilization. Consistent with these observations, there are no areas adjacent to the Elk, Bear, or
Hubbard Creek drainage channels that are currently being cultivated, nor a there any evidence of
prior cultivation or flood irrigation. The following s„n,rt,~.;>P site-specific observations from the
reconnaissance level AVF investigations for the E115 Bear, and Hubbard Creek drainages:
The identified alluvial deposiu are generally confined to the creek beds in both Elk and Bear
Creeks and sub-imgation features, where apparent, «cur immediately adjacent to these creek
beds in narrow strips. Conditions in Hubbard Creek are generally sittrilar, although, a broader
alluvial floor area exisu near the former Sunflower Energy Corporation's Blue Ribbon Mme.
The mapped limiu of the alluvium and sub-irrigated areas are shown on the Regional
Geology/Hydrology Map, (Map 2.04-M2).
The Hubbard Creek drainage channel and the adjacent valley sideslopes are characeristic of
area where the surficial geology corisisu of alternating weak shales and strong, weather-
resistant, cliff forming sandstones. The unconsolidated alluvium/colluvium which «curs in
the Hubbard Creek drainage a the result of weathering and failure of the weaker shales, and
consequent undercutting, and collapse of the stronger, weather-resistant sandstones. These
materials can generally be characterized as rtrixed slope wash and talus materials which may
not qualify as unconsolidated streartrlaid deposiu under the AVF definitions.
• There u little or no potential for economic agricultural utilisation in these areas due [o the
limited size and configuration of the areas, their remote 1«ation, the steep gradienu of both
the drainage valleys and surrounding terrain, and the limited potential for effective flood or
sub-imgation imposed bythe topography The potential for cultivation in the wider portions
of the Hubbard Creek drainage u limited due to the rocky surficial materials, limited areas,
remote 1«ation, and poor configuration for cultivation.
PR04 2.06-3 Revised August 2000