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additional borehole locations are proposed and permitted in the WMD in panels 14, 15, 16, and 17. All four locations
<br />are along County Road 27 with 14 -Left and 15 -Left on the East side and 16 -Left and 17 -Left on the west side, all are
<br />within 700 feet of County Road 27. All boreholes will be drilled into the inby panel of their associated panel, the
<br />depths are 1,370 feet, 1381 feet, 1408 feet, and 1405 feet respectively.
<br />Three additional thickener underflow boreholes will be added in the SWMD in 2016 and 2017. The first SWMD
<br />Thickener Underflow Borehole will be located near the Fish Creek Borehole road where it joins RCR27. Two
<br />alternate borehole locations have been identified, only one of which will be initially constructed and developed. The
<br />first location 1 (in Panel 2SW) is located on the west side of RCR27 between the west entrance and the Fish Creek
<br />Borehole road, and has been selected for construction through TR16-86. The second location (in Panel 1 SW) is
<br />located on the east side of RCR27 and will be accessed from the Fish Creek Borehole road this location was an
<br />alternative and will not be constructed at this time but may be a potential site in the future. The SWMD Thickener
<br />Underflow Borehole in 2SW will extend from the surface into the sealed SWMD mine workings at a maximum of
<br />approximately 750 feet. TC also constructed a test borehole (Sandstone Sub Test Borehole) to evaluate conditions in
<br />the 3SW Gateroad (WMD) for a future thickener underflow borehole. The test hole is located on the existing
<br />Sandstone Substation pad, and will be directionally drilled to intersect the 3SW Gateroad at a depth of approximately
<br />420 -feet. Conditions in this area were favorable, TC converted the test borehole to a thickener underflow borehole,
<br />which involved boring the test hole out to 22 to 24 inches for the surface casing and 12 to 15 inches for the finished
<br />borehole, setting and cementing a 16 to 18 inch surface casing to a depth of approximately 60 feet, setting and
<br />cementing a 8 to 11 inch borehole casing to a depth of approximately 420 feet, and setting an 8 -foot covered CMP
<br />manhole with lightening protection in-place to protect the well -head. The third proposed borehole will extend
<br />approximately 1,060 feet into the 1SW Panel at a location north of the Sandstone cliffs adjacent to the mine facilities
<br />in the SWMD. This borehole will be accessed from the existing ranch road which is used to access the Union Cellular
<br />tower from the Fish Creek Road. Minor road improvements to provide for year-round access will include limited
<br />grading, placement of water -bars and minor work on the existing ditches, and placement of gravel surfacing
<br />materials.
<br />In order for the thickener underflow to reach the 1 SWand the 12, 14, 15, 16, & 17 -Left thickener underflow boreholes,
<br />a pump boost station was installed at the 2SW borehole pad location. The pump boost station will consist of a one -
<br />foot thick, 20 x 20 foot concrete pad, a pre -fabricated pump building, the booster pump and piping connections, and
<br />a new power line ran from the facilities area to assist with electrical connections and pump controls.
<br />At each of these locations (except the Sandstone Sub location, where a pad already exists), a drill -pad and required
<br />drainage structures were or will be constructed. Buried thickener underflow pipelines have been or will be installed
<br />between the existing washplant facilities and the thickener underflow boreholes. The locations of the thickener
<br />underflow boreholes and the associated pipelines are shown on the Surface Facilities and Freshwater Systems Map,
<br />Map 24 (1/4). Design information for the thickener underflow boreholes and pipelines is provided in Exhibits 49K and
<br />49S.
<br />Installation of the thickener underflow boreholes generally involves placement of construction erosion controls (silt
<br />fence and/or straw wattles), removal and windrowing of available soil materials from pad areas and the road
<br />margins, construction of designed drainage structures (ditches and rock sumps), grading to establish level drill -pads
<br />and construct or improve roads, placement of gravel as surfacing for the light -use road, excavation of temporary
<br />cuttings pits on the drill -pads, drilling and casing of the boreholes, and installation of protective access manholes. On
<br />completion of drilling and casing operations, the cuttings pits are allowed to dry -out, material excavated from the pits
<br />is replaced and graded, and the pad surface is graveled to control erosion and sediment and provide an all-weather
<br />operating surface. The completed thickener underflow borehole installations include light -use road access, one or
<br />more soil material stockpiles (pad and road); the drill -pad (1MN — 25 x 180 feet, 6RT- 70 x 70 feet, 7RT — 100 x 75
<br />feet, 2MN — 75 x 75 feet, 2SW — 250 x 170 feet max., 1 SW — 175 x 175 feet max, Sandstone Sub — 75 x 75 feet, 12,
<br />14, 15, 16, 17 -Left — 200 x 200 feet max); the 6- to 12 -inch cased boreholes, 16 to 18 -inch cemented surface casings,
<br />and covered 8 -foot diameter CMP culvert manholes with lightning protection. The Sandstone Sub Borehole, because
<br />it will be completed on the existing substation pad, will not require soil handling, an access road, pad construction, or
<br />surface casing or a manhole, and drainage will be contained on the pad by a constructed berm.
<br />TRI 8-90 2.05-32.5 04/05/18
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