99 -- Nacimiento Copper Mine Site Operable Unit 2

The Nacimiento Copper Mine Site Operable Unit 2 is located in Sandoval County, 3.5 miles southeast of Cuba in northwest New Mexico on State Highway 126. In the 1980s, over 250,000 gallons of sulfuric and ferric acid was injected into the Agua Zarca aquifer to extract cooper. The acid was left in place resulting in the average pH of 3.59 and heavy metals above New Mexico State standards. This remedial action will pump contaminated ground water from the aquifer, surface treat it and release it into an unnamed channel. The project will pump up to 120 gallons per minute of groundwater via a series of new extraction wells to the surface. This water shall be treated using a semi-passive alcohol-enhanced bioreactor system (SPAEBS). The SPAEBS will utilize biological cultures to remove metals to the more stringent of New Mexico applicable groundwater and surface water standards. The treated water shall be discharged through an engineered drainage channel armored with riprap to prevent erosion and sediment transport and to provide aeration to surface water drainage. The main components of the required system are as follows: GROUND WATER EXTRACTION SYSTEM „X Nine extraction wells „X One new monitoring well „X Two 3,000 gallon above ground storage tanks „X Supply pumps „X Level control alarm system „X Piping from the extraction wells to the storage tanks and to the SPAEBS „X Supply pumps SPAEBS „X Sodium hydroxide feed system, including 3,000 gallon tank and two metering pumps „X Lined settling pond, 15 feet deep - 140 long and 100 feet wide „X Ethanol feed system, including 3,000 gallon tank „X Nitrogen feed shed „X Lined bioreactor - 15 feet deep, 70 feet long and 200 feet wide „X Recycle loop, including piping and recycle pump „X Chemical supply alarm system EFFLUENT DISCHARGE SYSTEM „X Discharge pipe „X Limestone lined discharge channel The operation and maintenance of this system for one year, with three option years is included.