Field Evaluation of Hydraulic Backfill Compaction At the Lucky Friday Mine, Mullan, Idaho.
NTIS: PB 203 657 :24 pages
The Bureau of Mines instrumented two similarly backfilled stopes-- one filled in the normal manner and the other with the fill densified using vibratory compactors--to evaluate the effect of fill compaction on subsequent vein-wall closure, proposed as an adjunct process for strengthening cemented fill. Hydraulic pressure cells to monitor pressures within the fill and mechanical closure devices to measure vein-wall movement and the procedure for their installation are described. The field compaction work was generally performed manually by utilizing small commercial concrete vibrators. A prototype immersible vibrator using slusher cables to propel the vibrator in the stope was used on several lifts of fill. Although compaction efforts were less effective than anticipated in increasing the final density of the fill, analysis of the field data does indicate somewhat improved strain characteristics and an increased pressure buildup for the densified fill. The effects of a prolonged period of inactivity and of rock burst occurrences in the immediate area also reflected in plots of strain and pressure within the two instrumented stopes.
IH; Report of Investigations
NTIS Accession No.
NTIS: PB 203 657