Gravity circuit conveyors

The project which consumed most of my time at Greens Creek was the gravity circuit redesign. Our gravity circuit consisted of 2 banks of spiral conveyors which separated the precious metals from the non-precious metals. After running through the spirals, the slurry in then conveyed to the next section of the circuit depending on the slurry content. Due to the abrasive nature of the slurry these conveyors would periodically wear out. My job was to redesign this system in order to:

• increase precious metal recovery
• decrease in feed water consumption
• increase conveyor life

Tails Conveyor
Tails Conveyor with iron filings build up
Conveyor bank

After hours of discussion with the management team, the maintenance mechanics, and the mill operators I began designing the new conveyors. The final conveyors consisted of metal housings with polyurethane inserts (for easy replacement) placed at a steep angle to increase gravity flow. We also modified the conveyor transfers in order to improve precious metal recovery. Unfortunately I was unable to get any pictures of the final product as the project was completed after my internship. As requested, I traveled back up to Juneau in November in order to supervise the installation of these conveyors but the barge shipment was misplaced and arrived weeks later.

** During the design process a large magnet was installed on the discharge chute of the ball mill. This helped greatly to eliminate iron filings other debris which greatly damaged our liners.

Honda