2012-08-24_REPORT - M1980244 (11)

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"W11=16 Confirmatory drilling was performed at Underground Working #4031. A drill pattern was set out by an AMEC field representative. Twenty holes were drilled encountering eight voids. An approximate total of 1,000 lineal feet was drilled. As -built survey of the drill holes was performed by Ames. Confirmatory drilling was performed at Underground Working #4047. A drill pattern was set out by an AMEC field representative. Thirty -one holes were drilled encountering thirteen voids. An approximate total of 1,550 lineal feet was drilled. As -built survey of the drill holes was performed by Ames. Confirmatory drilling was performed at Underground Working #4052. A drill pattern was set out by an AMEC field representative. Ten holes were drilled encountering two voids. An approximate total of 500 lineal feet was drilled. As -built survey of the drill holes was performed by Ames. Confirmatory drilling was performed at Underground Working #4058. A drill pattern was set out by an AMEC field representative. Nineteen holes were drilled encountering four voids. An approximate total of 950 lineal feet was drilled. As -built survey of the drill holes was performed by Ames. Grouting of "miss" (non -void) confirmatory drill holes was performed at Underground Workings #4007, #4031, 4051, and #4053. A grout pump and laborers were used to place bentonite grout into the "miss" drill holes. Q Remediation Remediation of Underground Working #4016 continued as the fill progressed in the area. A CAT 345 excavator was used to place small lifts of overburden fill into the working and bucket tamp the material. This was performed due the working being too narrow for the CAT 563 vibratory smooth drum compactor to be used for compaction. Placement of a three -layer geogrid cap extending 15 feet from the working location identified during confirmatory drilling was then performed. Approximately 1,875 square feet of geogrid was placed and accepted by an AMEC field representative prior to select structural fill placement. Approximately 100 cubic yards of select structural fill was then placed between each geogrid layer in a 6 -inch compacted lift. Prior to compaction the select structural fill material was moisture conditioned using a CAT 773 water truck. Compaction of the select structural fill was then performed using a 10 -ton smooth drum compactor using the static method. One nuclear density test was performed with results passing. Moisture - density relations were performed in accordance with ASTM D698 -07. Remediation of Underground Working #4020 was performed using a John Deere 850 excavator to excavate the blasted crown pillar from the working. Coarse shaft backfill material was then placed in the working. The material was placed in small lifts and bucket tamped until access for a CAT 563 vibratory smooth drum compactor was achieved. The material was then placed in 18" to 24" lifts. Each lift was moisture conditioned using a tandem axle water truck (when necessary) and compacted using a 10 -ton vibratory smooth drum compactor, passing over the entire fill surface at least 4 times (method compaction technique was applicable). An AMEC field representative observed the remediation of the underground working. A CAT 330 excavator was used to excavate the blasted material from Underground Working #4024. An AMEC field representative observed the crown pillar excavation. The stope was found to be completely removed up to the shaft. An AMEC field representative inspected the working MEW Weekly Report WE 03.24.2012