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Peabody Energy <br />• Approximately 82 yards of earth will need to be excavated from the area in order to install the leach field <br />base and liner. Some trench work will be required in order to run the leach field drain line to the oil -water <br />separator in the sump (see Drawing #070810C.) <br />b. Soil Preparation: <br />The soils in this area consist of unconsolidated shales, sandstone and some coal. In order for the leach field <br />to function effectively all these soils must be removed. The top foot of soils directly underneath the liner <br />should be compacted and the drain line installed prior to installing the lining. <br />c. Piping: <br />The leach field drain line is to be a six inch diameter, DR11, HDPE pipe. It will run downhill, at a grade of <br />approximately 2 %, to the oil water separator in the sump. Approximately 140 feet of piping will be <br />required for this run. <br />d. Leach Field Installation: <br />In order to contain both nuisance spills and large fuel tanker spills within the leach field, a geomembrane <br />type HDPE plastic liner is to be installed approximately five feet below grade. All seams in the liner are to <br />be heat welded. The liner should be installed sloping towards the drain line in the center of the leach field. <br />The liner is then to be covered with one inch of sand and the field area backfilled with 3 inch minus <br />crushed stone. Because it may be necessary, as part of regular maintenance, to excavate the leach material, <br />yellow caution tape should be placed on top of the sand layer to indicate the proximity of the liner. <br />e. Oil -Water Separator: <br />The oil -water separator, to be provided by Twentymile, will be capable of handling a spill of up to 4,000 <br />gallons of petrochemicals. It is to be installed by the contractor in the sump area as noted in Drawing <br />#070810C. The inlet of the separator will be connected to the leach field drain line and filled with water. <br />If fuel is spilled, it will flow through the leach field and down the drain to the separator where the fuel will <br />• displace water. Fuel will be retained in the separator by a series of baffles and overflow water will flow <br />into the sump. <br />L Grading: <br />After the leach field, drain line and separator have been installed the area surrounding the installation is to <br />be re- graded and sloped to restore proper drainage to the area. <br />5. Tipple Diesel Storage Tank: <br />The tipple area diesel storage tank is actually two 8,000 gallon tanks with a shared secondary containment basin. <br />The tanks are the older style single - walled vessels with a rectangular steel catchment basin surrounding them (see <br />Drawing #070810G and Picture #070910E.) These tanks are primarily used to fuel dozers working in the tipple area <br />and pushing coal on the BOB stockpile. Because of dozer use, TCC has decided to install a leach field and oil -water <br />separator system to serve as containment for fueling spills. <br />a. Excavation: <br />Approximately 82 yards of earth will need to be excavated from the area in order to install the leach field <br />base and liner. Some trench work will be required in order to run the leach field drain line to the oil -water <br />separator behind the sample building (see Drawing #070810D.) <br />b. Soil Preparation: <br />The soils in this area consist of unconsolidated shales, sandstone and some coal. In order for the leach field <br />to function effectively all these soils must be removed. The top foot of soils directly underneath the liner <br />should be compacted and the drain line installed prior to installing the lining. <br />c. Piping: <br />• The leach field drain line is to be a six inch diameter, DR11, HDPE pipe. It will run downhill, at a grade of <br />approximately 2 %, to the oil water separator behind the sample building. Approximately 60 feet of piping <br />will be required for this run. <br />SLC-5537792 -7 11 <br />