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0 0 ' miscommunication between the field personnel and the batch plant personnel. This mix was used to abandon Wells MW-1 and 5 and MW-2 to a depth of ' 35 feet. The mix design used on June 2 to completed MW-2 and 3 consisted of 50 percent portland cement and 50 percent pozzolan as proposed in the Work Plan submitted and approved by the SJPHS. Since this mix contained no bentonite gel to take up the free bleed water, a black colored residue from ' the pozzolan was observed floating atop the free water surface. X-ray diffraction analysis performed on the black colored residue showed the presence of hydrated cement with traces of quartz (Halliburton Report dated ' June 11, 1992 attached under Appendix E). On June 3, the mix design was changed at the request of SJPHS to consist of ' 96 percent of portland cement and four percent of bentonite gel. This mix was used to abandon Wells MW-4 and 6. ' 6.2 Density Measurements - A field density measurement was performed by BSK personnel on June 2 during the completion of the abandonment for MW-2 with a Mud Scale. The result indicated that the measured density of the ' return flow grout was 13.7 ppg. The measurement was performed on the 50:50 portland cement/pozzolan mix with bentonite. On June 3 prior to the abandonment of MW-4, a grout sample was tested for density. The result of the grout before pumping was 13.2 ppg. A second density measurement was obtained after completing the perforation at 36 feet. The measured field density of the return flow grout was 13.7 ppg. These field density determinations compare favorably with the grout (slurry) density recorded by Halliburton's Compupac for MW-4 (refer to Table 5-1 and Data Log for MW-4 in Appendix D). 6.3 Compressive Strengths - It was BSK's intention to obtain compressive strength data on the grout mix prior to pumping and from the return flow mix during the final day of abandonment operations. Owing to the fact that the grout t mix design was changed at the request of SJPHS for the final day of operation, compressive strength data on the portland cement/pozzolan mixes were not obtained. Previous strength data collected by others on cement/pozzolan mixes is presented in Appendix E for comparison with a ' cement/bentonite mix. In order to evaluate the compressive strength of the grout batched on June 3, three compressive cylinders were molded in two-inch by four-inch plastic molds for grout prior to pumping and return flow grout. The cylinders were transported to BSK's Material Laboratory in Pleasanton and stripped from the molds on June 4. The specimens scheduled for the 24-hour breaks were loaded to failure on June 4 and the specimens scheduled for the 7- and 28-day ' breaks were allowed to cure in a lime-water bath maintained at 73 ± 3° F. 13 tAssociates