A challenging project to renew the support plinths of a WA goldfields ball mill proved that Parchem Construction Product s’ Conbextra products are worth their weight in gold.

The ball mill - shaped something like an enormous cement mixing bowl - utilises large ‘balls’ of iron to crush the gold ore before it undergoes various chemical processes to remove any impurities.

The large weight of the structure, coupled with constant vibrations and the use of saline water to wash down the supports (due to the lack of potable water on site), had resulted in significant deterioration of the concrete support plinths.

Repair work required the removal of all affected concrete, rust and reinforcement contaminants, and the pouring of Parchem’s Fosroc Conbextra EP65 in the largest possible volumes while the mill was still running.

In order to meet the “no shutdown” requirements, Parchem conducted pre-project trials to ascertain whether larger-than-normal pours of up to 200L of epoxy could be utilised on the job.

Using an aggregate as a heat sink, the trials showed that volumes significantly higher than the customary 60-70L could be achieved. “We poured 150L in one hit,” says Parchem area manager, Gavin Bentley, “and tested the temperaturs to make sure that everything was going to be okay. The Conbextra EP came through with flying colours.”

The result was that the repairs to the plinths were

able to be completed without necessitating a major shutdown.

Source: Building Products News.