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A hydraulic fill retaining barricade failed at the Bronzewing mine in Western Australia in June 2000, resulting in the release of 19 000 m3 of saturated hydraulic fill into the mine and causing the deaths of three miners. The practices and procedures of mines using hydraulic fills came under scrutiny by regulatory bodies and mining companies. The use of hydraulic fill at the Scuddles mine was suspended and waste rock became the sole backfill material. Development of the Gossan Hill Cu-Zn mine adjacent to Scuddles had progressed by 2003 to a point where a self- supporting fill material was required to enable full recovery of high- grade ore. Cemented hydraulic fill (CHF) was identified as the optimum fill type and work began on designing appropriate management procedures and controls to ensure the safe implementation. This included definition of the fill properties, plant design and construction, reticulation system design, design of stope barricades and drainage systems and fill placement control and monitoring practices. CHF placement began on 16 July 2004 and has continued to date., A hydraulic fill retaining barricade failed at the Bronzewing mine in Western Australia in June 2000, resulting in the release of 19 000 m3 of saturated hydraulic fill into the mine and causing the deaths of three miners. The practices and procedures of mines using hydraulic fills came under scrutiny by regulatory bodies and mining companies. The use of hydraulic fill at the Scuddles mine was suspended and waste rock became the sole backfill material. Development of the Gossan Hill Cu-Zn mine adjacent to Scuddles had progressed by 2003 to a point where a self- supporting fill material was required to enable full recovery of high- grade ore. Cemented hydraulic fill (CHF) was identified as the optimum fill type and work began on designing appropriate management procedures and controls to ensure the safe implementation. This included definition of the fill properties, plant design and construction, reticulation system design, design of stope barricades and drainage systems and fill placement control and monitoring practices. CHF placement began on 16 July 2004 and has continued to date.

Problems with the ground conditions around old workings at the Western Australian mine required the development of alternatives to conventional downhole blasting. Losses of consumables in broken ground and small voids were reduced by the introduction of foam and polymer drilling, which also helped to keep drillholes open after retraction of the drill string. Aquacrete was also used successfully to fill voids and the blocking of holes by broken material before charging was prevented by using rigid PVC liners for completed holes. Large-scale ground movements will still result in the loss of holes but these techniques, coupled with the prudent application of just-in-time drilling, have allowed holes to be drilled and charged effectively through most delaminated ground., Problems with the ground conditions around old workings at the Western Australian mine required the development of alternatives to conventional downhole blasting. Losses of consumables in broken ground and small voids were reduced by the introduction of foam and polymer drilling, which also helped to keep drillholes open after retraction of the drill string. Aquacrete was also used successfully to fill voids and the blocking of holes by broken material before charging was prevented by using rigid PVC liners for completed holes. Large-scale ground movements will still result in the loss of holes but these techniques, coupled with the prudent application of just-in-time drilling, have allowed holes to be drilled and charged effectively through most delaminated ground.