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Larenci(o Cartvort Minc - Groundwa(er Techmra! Reoar( <br />• <br />of the formation (Howard, 1982). Within the permit area no water was encountered in the Poison <br />Canyon and very little water in the Raton Formation overburden. <br />Recharge to the overburden is via precipitation, since this unit forms the highest topographic unit <br />in the permit area. Much of the water from precipitation events is lost to evapotranspiration or <br />to runoff. Some of the water does i~ltrate through the sandstones of the Poison Canyon, into the <br />overburden. <br />Examination of a flow net of the system (Figure GW-81, indicates that some of the recharge into <br />[he Poison Canyon Formation is discharged via evapotranspiration from the formation itself. <br />Particular to the permit area, several of the principal springs are thought to emanate from the <br />Poison Canyon/Raton Formation contacts. Springs in the Bonita Canyon area of the project <br />emanate from underneath massive sandstones that are indicative of the Poison Canyon, and may <br />provide a mechanism for discharge from this formation. Discharge from springs would reduce <br />the amount of water entering as recharge to the underlying units. <br />Groundwater in the overburden is characterized as being under confined conditions. Water was <br />not apparent in any of the borings into the overburden; therefore, wells were set into the sandstone <br />overlying the Ciruela. The wells at location MW-2 have been dry and two of the three planned <br />• wells were not set at the location for MW-3 due to dry conditions. Water was present in only one <br />well installed in the overburden (MW-lA). Groundwater in the overburden appears to be <br />intermittent throughout the zone; therefore the potentiometric surface could not be determined. <br />The physical characteristics of an overburden water-bearing zone could not be determined. A slug <br />test was attempted in well MW-10, and no recovery from the initial "slug in" was recorded in <br />eight hours of data collection. This indicates an extremely low hydraulic conductivity for the <br />sandstone immediately overlying the Ciruela. Although not quantifiable, estimated hydraulic <br />conductivity would be in range of 10-' to 10-6 ft/day. Accordingly, the water-bearing zone is <br />confined and the range of these values is generally 10' to 10~ (Heath, 1983). Bailing of the well <br />during the acquisition of field chemistry parameters indicates that the hydraulic conductivity in this <br />layer is extremely low, since water production from the well is limited. The potential production <br />of water from this zone for domestic water would be characterized as poor to infeasible. <br />Ciruela Coal <br />The Ciruela Coal in the Lorencito Canyon Permit area outcrops at approximately 7200 feet <br />AMSL. The outcrop is considered the downgradient extent of this unit for hydrologic analyses. <br />Total estimated thickness for this unit ranges from 0 to 5.9 feet with an average thickness of 3.56 <br />feet. Recharge to the Ciruela is via precipitation on outcrop surfaces, and from inflow from <br />fractures or overlying units. Infiltration rates for this unit are anticipated as low. <br />• <br />Groundwater a75\Deccmber 9. 1996 37 <br />