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Due to the fact that the pH is being elevated, it was decided to have sulfuric acid available in the event a pH
<br />adjustment was needed prior to the effluent discharging from the system. The chemical and equipment for this
<br />procedure is housed in the chemical storage building located on the west side of the west cell as shown on Map 32.
<br />• This system will be used only if the effluent approaches the pH discharge limitation of 9.0.
<br />In 2006, the sodium hydroxide system was replaced with an electro-coagulation system which achieves the same
<br />result through ionization and agglomeration of particulate iron. The treatment ponds and associated surface
<br />facilities and systems will be removed and disturbed areas reclaimed when no longer needed for treatment of mine-
<br />water discharge. Reclamation plans for this facility are summarized on page 2.05-105.1.
<br />Eastern Mining District - Dewatering Borehole and 6MN Mine Water Transfer Line (MIt07-2241
<br />The EMD Dewatering Borehole installation consists of two components: 1) Dewatering borehole, control building,
<br />and transfer pipeline (existing), and 2) Treatment facilities (possible future). The EMD (or 10-Right) Dewatering
<br />Borehole draws from the sump developed off of the 10-Right entry (refer to Map 23, Mine Plan, for the location of
<br />the sump). An access/light-duty road was constructed to the borehole site from RCR33. The initial 1,600 feet of
<br />this road required new construction, while the remainder of the road (3,000 feet) involved upgrades to the existing
<br />ranch road. For definition purposes, the beginning 700 feet is an access road and the remaining 3,900 feet is a
<br />light-duty road. The location of the access road is shown on Maps 17 and 18. The location and alignment of the
<br />initial 1,600 of the road differs slightly from the original proposal in order to provide for greater visibility and
<br />safety at the junction with the existing road.
<br />During construction of the road, approximately 6,800 CY of soil material was windrowed to the side of the road.
<br />This volume is based on constructing a road 4,600 feet long and 20 feet wide, and salvaging soil material to a depth
<br />of 24 inches. The stockpiled soil material was seeded with the pastureland seed mixture at the specified rate. The
<br />finished width of the road is approximately 12 feet, and it is surfaced with approximately 9 to 12 inches of 6-inch
<br />pit run gravel and 3 to 4 inches of 1 '/z-inch road-base or crushed rock. Culverts were installed at minor drainage
<br />crossings along the road alignment. Design calculations for these culverts, numbered EMD-1 through EMD-4, are
<br />• provided in Exhibit 8a, Culvert Sizing -EMD Dewatering Facility Access Road.
<br />The EMD Dewatering Borehole installation consists of a graveled pad azea, the 14-inch cased borehole, the pump
<br />and control building, a power distribution line, and the transfer pipeline. The pad area is approximately 100 x 200
<br />feet, and during borehole drilling operations, two 10 x 10 x 50 foot mud pits were excavated. On completion of
<br />drilling, the mud pits were backfilled with excavated material. A nominal 17.5-inch diameter borehole was drilled
<br />into the sump area, approximately 1,350 feet of 14-inch metal casing was installed in the drillhole, and the annular
<br />space was grouted. A submersible pump capable of pumping 350 gpm was installed in the casing. To complete the
<br />well installation, an 8-foot length of 8-foot diameter corrugated metal pipe with lid was placed over the borehole as
<br />a surface casing. The material excavated from the 8-foot diameter pit was spread over the pad. The control
<br />building is approximately 10 x 10 x 10 feet, and sets on a concrete pad 10 x 10 x 0.5 feet. A transformer was
<br />installed at the site to provide electrical power for the pump, with a 7-foot high security chain-link fence around its
<br />perimeter. A powerline, approximately 1.5 miles in length, was constructed to tie this location into TCC's power
<br />system.
<br />A 6-inch riser pipe from the submersible pump extends from the 14-inch casing, and connects to the 8-inch HPDE
<br />transfer line to FCM-2. If desired, in the future, the discharge line could also be tied into a sepazate feed line to
<br />treatment ponds at the 10-Right location. HDPE pipe is extremely flexible. With a cold bend radius of 160 inches,
<br />the pipe can be offset 80 inches vertically over a length of 160 inches. This greatly exceeds any potential offset due
<br />to surface subsidence. The current transfer pipeline, and any future piping to treatment ponds, is buried to
<br />minimize freezing problems. The existing transfer pipeline is approximately 7,300 feet long. Any future feed line
<br />for the water treatment ponds would be approximately 4,300 feet long. In conjunction with construction of the
<br />6MN Facilities project, a valved connection was established on the existing transfer line, and a sepazate 7,750 foot
<br />transfer pipeline was constructed to the existing 6MN Million-Gallon Tank. Supplemental control equipment was
<br />. added to provide for operation of the valves and to allow remote shut-off of the submersible pump for both
<br />maintenance, and in the event of a tank high-level alarm.
<br />MR07-224 2.05-77.1 10/17/07
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