|
areas where the waterline was installed in the road corridor, the trench was excavated either down the center of
<br />the road or along the shoulder. Field conditions dictated the location of the trench excavation. Up to five
<br />manholes are located along the waterline, with installed "T's" to provide taps for setting up feeder -lines to deliver
<br />water to stock tanks. All of the installations are of similar construction, with a 5 -foot diameter culvert with
<br />insulated lid for manhole access, and a valve and "T" -connection to the waterline. Any feeder -lines will run
<br />overland from the manholes to stock tanks and the water will be used for stock watering. A float device, or other
<br />type of control, will be installed at the stock tank to control flows to the tank. The locations of the manholes were
<br />determined in the field based on topography and stock water distribution needs. The segment of the line which
<br />traverses the former surface mine area required that available topsoil be salvaged, and then replaced on the trench
<br />excavation. For this segment, topsoil was salvaged and placed to one side of the trench and subsoil excavated and
<br />placed on other side of trench, the waterline was bedded and placed in the trench, the trench backfilled with
<br />subsoil, then topsoil was replaced over the footprint of trench, and the area was broadcast seeded with the
<br />approved seed mixture.
<br />In 2007, (MR07-216) the Fish Creek Ventilation Shaft was converted to a dewatering well to replace the Fish Creek
<br />South Dewatering Well, where a defective dewatering pump became stuck down -hole in the well and could not be
<br />retrieved for repair or replacement. The original Fish Creek Dewatering System consisted of two adjacent dewatering
<br />installations. Each of the two 12.75 -inch O.D. Fish Creek North and South Wells house a 6 -inch discharge pipe,
<br />electrical cable, and a 300-600 gpm capacity submersible pump. Electrical power is supplied by the distribution
<br />powerline depicted on Map 39, Foidel Creek Mine Powerline Location. The substation location for the dewatering
<br />wells is shown on Maps 26 and 39. At this location, after topsoil removal, a fence was constructed around the
<br />perimeter of the site, enclosing an area of approximately 48 x 24 feet. Within the fenced area, a 12 x 12 x 1.5 foot
<br />concrete pad was poured and a four -pole structure was constructed. The general layout of this site is shown on Figure
<br />18. A gravel blanket, approximately 6 inches deep, has been placed around the concrete pad and extends to the fence.
<br />During the life of the facility, weeds will be controlled within the fence using selective herbicides. As previously
<br />noted, the Fish Creek South Well has been replaced by the Fish Creek Ventilation Shaft Dewatering Well.
<br />Pumped mine water from the Fish Creek North Dewatering Borehole, and Fish Creek Ventilation Shaft Dewatering
<br />Well is transferred to either buried 8 -inch HDPE connector lines and a distribution point (to water treatment system),
<br />or to a 12 -inch pipeline which transfers water back to the Area 1 Pit Mine Water Storage Reservoir. At the
<br />distribution point, the flow is metered and regulated to discharge a desired quantity of water to the electro -coagulation
<br />system and treatment ponds, and to return any excess flow to the mine through a recirculation line that discharges into
<br />the Fish Creek Ventilation Shaft Dewatering Well. The recirculation line allows the borehole pumps to run at rated
<br />capacity, while regulating discharge from the treatment ponds at a lower rate. The recirculation line is a 4 inch HDPE
<br />pipe, buried underneath the road on the east side of the east cell. The recirculation line ties into the mine water
<br />discharge line in a manhole placed in the north berm of the eastern cell. Also within the manhole are valves to direct
<br />flow to the recirculation line, and flow meters for monitoring the mine water discharge line and the recirculation line.
<br />When the line and manhole are no longer needed, they will be removed from the site as part of the final reclamation
<br />process.
<br />In the Spring of 2006, an electro -coagulation system replaced the existing sodium hydroxide (caustic) system for
<br />treatment of water pumped from the Western Mining District at the Fish Creek Borehole. Safety, maintenance,
<br />and cost benefits were the primary reasons for replacing the existing caustic treatment system. The electro-
<br />coagulation system applies a constant electrical charge to the incoming mine water, ionizing particulates in the
<br />water feed stream, and causing the charged particles to agglomerate (coagulate), and drop-out. The existing
<br />treatment ponds will still be used to capture the precipitates from the treatment process. The system is essentially
<br />a modular system, housed in two metal shipping containers; the equipment is housed in a 40 x 8 x 10 foot high
<br />container mounted on poured concrete piers; the other 25 x 25 x 24 foot container, containing the process tank,
<br />valves, and flow metering equipment sets on a 6 -inch thick monolithic concrete pad. The containers housing the
<br />system are located immediately east of the electrical control building. An 8 x 19 foot, 5,000 gallon water tank is
<br />installed in one corner of the second container. Power for the EC system is supplied from the adjacent substation.
<br />One powerpole was previously installed adjacent to the caustic building, an additional powerpole may be
<br />necessary, which can be used with one or more drop -lines to provide power to the EC buildings. Please refer to
<br />the attached Exhibit 49G drawings, depicting the layout of the proposed buildings and associated piping, as well
<br />as the supporting text for construction details. Map 24 (sheet 3 of 3) also shows the general EC facility location.
<br />MR16-299 2.05-50.2 06/16/16
<br />
|