Dredging operations, using bucket ladder dredges floating in paddocks, involve digging and lifting of the alluvium by a chain of about 130 buckets. The tin-bearing alluvium is discharged from the buckets and fed to an on-board treatment plant - mainly comprising wet gravity separation process - to recover the tin in a concentrate form. The tailings are discharged to the back of dredge via tailings chutes.
Slimes generated from clayey ground during the dredging process are pumped from the paddock using slime pumps and settled in ex-mining ponds.
Gravel Pump (GP) Mining Operations
GP mining operations involve dozing of the tin bearing sand towards a gravel pump, assisted by high pressure water monitors, and pumping the resultant slurry to a nearby jig plant.
Prior to mining by gravel pump, the overburden is pre-stripped, using earthmoving equipment (EME) and dumped as back-fill or hauled to designated waste dumps.
EME fleets are equipped with machines that have proven to be both efficient and reliable in achieving the target productivity and cost effectiveness.
The GP mining operations are a closed circuit activities; tailings are pumped behind retention dams and the water decanted back to the mine for re-use. Tailings from the GP operations are backfilled into mined-out areas.