SITE INFORMATION AND CORRESPONDENCE

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SER 05 '89 13:45 LUHDORFf '?CALMAMINI WOODLAND P. 10i10 28 depth of approximately 300 feet and screened from a depth of about 260 to 290 feet. The construction features of the proposed monitoring facilities are summarized below. Direct rotary drilling methods are planned. Four-inch casing is planned for installation in a minimum 10-inch diameter borehole. PVC schedule 40 flush threaded casing and screen are planned. The estimated test hole depths are approximately 180 feet for the relatively shallower test holes (MW2 and MW3A) and approximately 300 feet for the relatively deeper test hole. C- The estimated screen slot size is 0.040 (.040 was the slot size for the screen installed in MWl); the screens in the shallower wells will be located from a depth of approximately 140 to 175 feet and in the deeper well from a depth of about 260 to 290 feet. i f The anticipated filter pack is Monterey or Lonestar 8 x 16 sand. Cement grout seals with five percent bentonite are planned. The shallower wells will be sealed to a depth of approximately 105 feet, while the deeper will be sealed to a depth of approximately 250 feet.—' The wells will be developed by airlift pumping and swabbing recr_.1 _ minimum of six to eight hours each. The new monitoring wells will be equipped with direct purge samplers similar to the one installed W1. 1. Investigation of Existing Monitoring Facilities Ten wells at the Briners facility have been monitored on an approximately quarterly frequency- Most of the wells in the current network are recommended for inclusion, along with the new facilities, in the interim verification monitoring program as discussed below. Drillers reports, or other information which documents well construction details, do not exist for five wells planned for inclusion in the ongoing monitoring program at i F i 9 i