Simberi Gold Mine ML‐01 Backing Liner Replacement

Overview of SOW

SAG Mill ML‐01, for the SAG the SOW was for ShieldCrete® International SDN BHD (SCS INT) to supervise WorkForce South Pacific (WFSP) in removing the old rubber lining & adhesive system from the shell & feed head outer lifter/liner area & filler ring areas both feed & D/C of the shell. Once all old rubber lining was removed then ShieldCrete South Pacific (SCSP) would sand blast the shell to SA2.5 profile and ensure the correct profile was achieved prior to coating with the ShieldPoly® F-15 at a DFT of 6mm (±0.5mm).

SAG Mill ML‐01

• Timing for the removal of the old rubber was estimated at 25hrs, removing old lining whether rubber is always a bit of an unknown as dependent on adhesion and damage on the lining being replaced this can vary greatly, this ended up taking 21hrs.
• Once the rubber was removed due to the dirty process water that also had some sea water mixed with it, we decided not to risk adhesion of the poly, we filled1,000l IBC containers with fresh Water and cleaned initially with a HP Water Blaster at 5,000PSI then did a final was with ShieldChlorid at a ratio of 50:1 with fresh clean water, this added 3hrs & 50mins to the job that was not in the planned schedule.
• Once cleaned and we were satisfied that there was not a risk of high chlorides on the surface we dry sandblasted the shell and feed head out using Dura-Grit #20/40 mesh garnet, consumption was slightly under 20kg/m2.

HP washing the shell.

•  We blasted sections on both sides of the shell and feed head and then applied the ShieldPoly® F-15 at 6mm DFT, then inched and blasted the next sections and repeated the F-15 application, as we have found this is much faster than blasting all the mill the applying the polyurea and also mean that the surface is clean and not contaminated from any materials in the mill with the ball charge.
• The time in the plan for the blasting and application of the F-15 was 25hrs, even with the additional time to wash any chloride contamination the blasting and application was completed in <15hrs over 10hrs ahead of schedule.
• Three additional jobs were done that were not in the SOW, this was blasting & lining the Feed End Trunnion Liner, blasting & lining the SAG Feed Chute Sand Ring, & blasting & coating the Apron Feeder Tail Assembly, all having 6mm DFT of ShieldPoly® F-15 applied. There was sufficient F-15 left over from the SAG so these two item were done at no additional costs.

Spraying the sandring with ShieldPoly® F-15.

Achieved 6mm DFT of ShieldPoly® F-15 applied.