PERMFILE139112

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 9/14/2005
• Section_Exhibit Name: 2.05 Operation and Reclamation Plans
• Media Type: D
• Archive: Yes

geotextile and road fill over the in-place soils. Given an average topsoil depth of approximately 6 inches
in the upland area and a total disturbance azea of approximately 1.4 acres, approximately 1,111 CY of
. topsoil will be salvaged from the road corridor, and 1,452 CY from the pad. The topsoil from these azeas
will either be windrowed adjacent to the road corridor or placed in stockpile adjacent to the shaft pad for
future reclamation use. The topsoil salvage volumes are indicated on Table 49A. Seeding with the
topsoil stockpile stabilization seed mixture will stabilize the windrowed and stockpiled topsoil.
Following topsoil removal, required drainage and sediment control structures will be constructed or
installed. These structures include designed culverts for the road crossing of Fish Creek (see Exhibit 8R,
Fish Creek Culvert Design, NW Mains Ventilation Shaft) and road crossings of smaller ephemeral
drainage channels; a temporary diversion ditch azound the upgradient perimeter of the shaft pad; runoff
collection ditches for the pad area topsoil stockpiles; a downgradient containment berm, and discharge
control structure (sump and rock check-dam) at the downgradient limit of the shaft pad. The drainage
from the shaft pad is addressed under a Small Area Exemption (SAE), as it is relatively small
(approximately 1.8 acres), and will encompass gravel-surfaced and/or reclaimed azeas. The access road
follows relatively level terrain and will be gravel-surfaced, so access road drainage control requirements
aze minimal. All drainage calculations and documentation is provided in Exhibit 8S, the SAE
demonstration is provided later in this section, and the drainage structures aze shown on Map 24. The
SAE demonstration includes ditch sizing for the upland diversion and road ditches.
The access road into the shaft pad crosses Fish Creek, and TCC will place "Buffer Zone" signs at the
boundary of the stream crossing disturbance. Except for the disturbance associated with the stream
crossing, no further activity is planned within the Buffer Zone boundary.
• Construction of the ventilation shaft access road involves topsoil recovery and windrowing or stockpiling,
installation of required drainage structures, scarification and re-compaction of surface materials,
placement ofgeotextile in selected areas, and placement and compaction of approximately 8 inches ofpit-
run gravel and 3 inches of road-base material. The access road surface will be approximately 22 feet wide
and will be graded and crowned to promote effective drainage. Road construction requires minimal cut,
and limited fills in the azea of the Fish Creek drainage crossing. Fill slopes will be graded to a 3H:1 V and
stabilized by seeding with the topsoil stockpile stabilization seed mixture. Preparation of the ventilation
shaft pad involves topsoil recovery and stockpiling, installation of required drainage structures, grading
and compaction to establish a level pad working area, excavation of mud pits for drilling of the shaft pilot
hole, temporary stockpiling of the excavated material, and placement of gravel surfacing material to
control dust and sediment from the pad azea. Mud pits will be approximately 20 x 20 x 8 feet, and are
sized to contain all drilling fluids. In the event unanticipated ground water flow is encountered during
shaft boring, the pits maybe enlazged or additional pits excavated to handle the increased flows.
The ventilation shaft pilot hole will be drilled using a reverse circulation drill rig to drill a 14-inch
nominal diameter pilot hole from the surface to a depth of approximately 1,450 feet. The shaft collar area
will be excavated to a depth of approximately 20-foot, acollaz-liner, consisting of steel ring-beams and
liner-plate will be placed, and the annulus between the liner and the collaz excavation cemented. A
temporary head-frame will be erected on the shaft collaz structure, over the pilot hole, to support and
handle the shaft boring equipment. The shaft boring drive-unit will be installed on the shaft collar
structure in preparation for shaft boring operations. During drilling, drilling fluids aze generally re-
circulated from the excavated mud pits, which will serve as temporary fluid reservoirs.
Shaft boring and casing of the approximate 20-foot diameter ventilation shaft aze conducted as separate
operations. Asurface-mounted drive unit is used to turn a rotary cutting head attached to a shaft
extending from the surface through the pilot hole, and a hoist on the temporary headframe is used to
maintain continuous upward pressure on the cutter head. As boring progresses, the cuttings are dropped
down the shaft bore and are recovered, transported, and placed in mined-out azeas underground. An
MROS-194 2.05-45.1 07/2/05