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In order to better define geologic conditions, a mine development drillhole was drilled in Panel 5 during 1990, as
<br />shown on Map 23A, Mine Plan. The drill -site location is shown on Map 23A inside of the boundaries of the drilling
<br />area. An existing ranch road was used as part of the initial access for the drill -site. The existing ranch road, as shown
<br />on Map 23A, ties into the access road to the site. Topsoil was not stripped for the new access road into the site, due to
<br />the prior disturbance. A ditch, inscribed above the drill -pad, divert upland flow away from the pad minimi runoff
<br />across the pad. The ditch, in combination with the limited size of the pad provided adequate drainage and sediment
<br />control for the site. The drill -site was approximately 100 x 100 feet, and topsoil was stripped and salvaged from the pad
<br />area. Following topsoil salvage, the site was leveled, mud pits were excavated within the pad limits, and the 6'/ inch
<br />diameter drillhole was drilled, using air /foam as the circulation medium, to a depth of approximately 1,200 feet.
<br />Drilling fluids and any water resulting from drilling operations was contained on -site by the mud pits. After
<br />drilling was completed, the hole was logged, and then plugged and sealed by grouting from the bottom to within
<br />three feet of the surface. A piece of rubber hose was placed in the top three feet, extending just above ground -level
<br />to serve as a marker, and the remainder of the hole was backfilled. Material excavated from the mud pits was used in
<br />backfilling the pits on completion of drilling, the site was regraded, the road was ripped, and all disturbance areas were
<br />seeded with the appropriate seed mixture. The required abandonment report was submitted within 60 days to the
<br />CMLRD. The reclamation bonding calculations for this activity are provided in Appendix A, Volume IA.
<br />In order to study potential effects of surface subsidence from longwall mining on the bases of lattice -type electric
<br />transmission towers, two test -sites were established overlying the l'- Southwest Panel. The location of the sites is
<br />shown on Foidel Creek Mine Map 40, Subsidence Monitoring Status Map. Each site consisted of four concrete
<br />pilings, 18 inches in diameter and 15 to 20 feet deep, with survey markers imbedded in the top of each piling in
<br />order to measure any settlement caused by surface subsidence. A drill -rig used to auger holes for the pilings
<br />accessed the test sites through an existing gate, using an existing ranch road. Cuttings from the auger holes were
<br />pulled back from the holes and scattered over the site. In mid -1995, at the conclusion of the study, the pilings were
<br />excavated and removed to a depth of three feet below the surface, the holes were backfilled, and the sites were
<br />regraded, topsoiled, and seeded with the appropriate seed mixture. The reclamation bonding calculations for this
<br />activity can be found in Appendix A, Volume IA.
<br />A development drillhole was completed in 1994, as shown on Figure 7A, 1994 Development Drill Hole Location. An
<br />existing ranch road was used as part of the access into the site, with the remaining short access involving overland
<br />travel. The drill -site was approximately 100 x 100 feet, and available topsoil was stripped, stockpiled adjacent to the
<br />site, and marked with a topsoil sign. A ditch was inscribed above the drill -pad to divert upland flow away from and
<br />around the pad to minimize run -on to the pad, and the ditch, in combination with the limited area of the pad
<br />disturbance, provided adequate drainage and sediment control for the site. Following topsoil salvage, the site was
<br />leveled as necessary, and mud pits were dug within the pad limits. The option existed to dig a trash pit on -site, or use
<br />an existing mud pit to collect trash, such as paper, cans, cardboard, etc., however, oily wastes were not be placed in any
<br />of the pits.
<br />The 6.25 -inch drillhole was drilled with air, water, foam, mist, or combination of these circulation media to a depth of
<br />approximately 1,100 feet. Drilling fluids and any water resulting from drilling was contained on -site in the mud pits.
<br />After the hole was completed, it was logged and then grouted from the bottom to within three feet of the surface. A
<br />piece of rebar was placed in the top of three feet of the grout to act as a permanent marker, and the remainder of the
<br />hole was backfilled with soil. The material excavated from the mud pits was backfilled into the pits, the area was
<br />regraded, and topsoil was replaced and reseeded with the approved seed mixture. The required abandonment report
<br />was submitted within 60 days to the Division.
<br />TCC installed an additional subsidence test site above the 3rd Southwest Panel to evaluate the possible effects of
<br />surface subsidence from longwall mining on the base of a lattice -type electric transmission tower (MR95 -125). The
<br />site consisted of four buried concrete pilings, 18 inches in diameter and 15 to 20 feet deep, with a survey marker
<br />embedded in the top in order to measure any settlement caused by surface subsidence. Site access, construction,
<br />monitoring, and reclamation were essentially the same as the test site previously described. The reclamation bonding
<br />calculations for this activity are included in Appendix A, Volume IA of the permit.
<br />TR08 -64 2.05 -14 06/17/08
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