In mines, quarries and aggregate bulk processing, large steel structures like hoppers that are used to store and dispense vast volumes of ore, rock and gravel are often subjected to abrasion, moisture and salt deposits, which can accelerate corrosion.
Once corrosion starts, often through a breach in traditional barrier-type coatings such as epoxies or polyurethanes, the coating can act like a greenhouse, trapping water, oxygen and other corrosion promoters. This allows the corrosion to spread quickly under the coating itself, which is difficult to inspect, and can lead to failure and costly premature replacement. For these reasons, such coatings are typically reapplied at a sizeable cost in downtime, surface preparation and coating application.