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development will add approximately 2,430 acres; and Interim Phase III development will add approximately 20
<br />acres to the affected area. Areas to be developed in the WMD during the current and subsequent permit terms are
<br />shown on Map 23 Mine Plan. Alignment of development entries may be adjusted, as necessary, to address geologic
<br />conditions. The preliminary development layout will include main and sub -main development work as described in
<br />the referenced Permit Revisions. The dimension of pillars in these development areas may vary based upon mining
<br />conditions. Sumps and ventilation doglegs will be added as needed. Locations for these minor operational features
<br />are not provided on Map 23, due to the need for some flexibility in the placement of these features.
<br />During the Phase I, Il, and Interim III WMD development, preliminary development work will be conducted under
<br />the Fish Creek AVF, Fish Creek, several powerlines, and several stock ponds. A more detailed discussion of
<br />undermining these structures is presented under the subsidence discussion. Because the preliminary development
<br />work (WMD, Panels 13- through 17 -Left)) will be limited to main and sub -main entry development with retention
<br />of support pillars, no subsidence will be associated with these activities.
<br />Underground Drillholes (MRO1 -172 — Withdrawn 07/11/01)
<br />2011 -2012 WMD Exploration Program (NM11 -256)
<br />TC proposes to construct drill -pads, and drill and log up to 7 exploration drillholes in the active WMD, in order to
<br />better delineate coal seam thickness and characteristics, and to more accurately define structural conditions,
<br />including faulting. The proposed drillhole locations as shown on Figure EX52 -F1, 2011 -2012 WMD Exploration
<br />Program, are on lands where TC is the surface owner, and the coal is under either fee (drillholes TCW001, 002,
<br />004, 005, 006, and 007), or Federal (drillhole TCW003) ownership. The proposed drill -sites have been evaluated
<br />for both potential cultural resource and wildlife impacts, as documented by the cultural resource survey report
<br />included in Exhibit 6L and the wildlife consultation letter provided in Exhibit 23C.
<br />Drill -sites have been selected and located to facilitate access from existing County and ranch roads. Where direct
<br />access from existing roads is not feasible, drilling equipment and supplies will travel overland short distances
<br />during periods when ground conditions are favorable, to access the drill sites. Drill pads will be approximately 75 x
<br />75 feet (0.15 acres), with soil material stripping limited to an area around the drillhole collar, and the area
<br />surrounding any containment pits necessary to support drilling operations, in order to minimize disturbance and
<br />facilitate site reclamation. If required, any containment pits will be excavated to provide sufficient capacity for full
<br />containment of both drilling fluids and materials, and any surface runoff from the pad areas. Drainage from drill -
<br />sites will be controlled by the containment pits, in combination with Alternative Sediment Controls (ASC's),
<br />including earthen berms, straw wattles, silt fencing, or other appropriate materials. Nominal 5.625 -inch drillholes
<br />will be completed using conventional rotary drilling methods and drilling mud as the circulation rnedium to depths
<br />ranging from 1,500 to 1,800 feet. Contract terms limit drilling compounds and additive to materials that are non-
<br />toxic and bio- degradable. Corehole samples will be recovered from some or all drillholes, and all drillholes would
<br />be geophysically logged. On completion of drilling and logging, all drillholes will be plugged and sealed in
<br />accordance with State Engineer requirements, and drill sites will be reclaimed by allowing any mud pits to dry-out,
<br />backfilling the pits and grading any disturbance to blend with the surrounding terrain and reestablish natural
<br />drainage patterns, replacing stockpiled soil materials, and seeding with either the rangeland or dryland pasture seed
<br />mixtures (dependent on the pre - disturbance vegetation community).
<br />2012 WMD Exploration Program (MR12 -261)
<br />TC proposes to construct drill -pads, and drill and log up to 5 exploration drillholes in the active WMD, in order to
<br />more accurately define structural conditions, including faulting. The proposed drillhole locations as shown on
<br />Figure EX52 -F1, 2012 WMD Exploration Program, are on lands where TC is the surface owner, and controls the
<br />coal through a valid existing lease. The proposed drill -sites have been evaluated for both potential cultural resource
<br />and wildlife impacts, as documented by the cultural resource survey report included in Exhibit 6L and the wildlife
<br />consultation letter provided in Exhibit 23C.
<br />Drill -site selection, access, construction, drilling and reclamation practices will be essentially the same as
<br />previously described for the 2011 -2012 exploration program. Nominal 5.625 -inch drillholes will be completed
<br />RN 12 -06 2.05 -17.1 04/01/13
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