A lime supply is needed for flue gas desulfurization. Sulfur in the flue gas is removed by spraying with lime slurry. Fine limestone powder is used for creating the lime slurry. The size of the lime storage silos vary from site-to-site, and even within the same site. Regardless of silo size, lime material is a very fine, dusty powder which is prone to heavy build-up on surfaces within the vessel. Due to the heavier weight of lime particles, lime powder piles up steeply and unevenly in silos, making accurate level measurement particularly challenging for operators. Because limestone is essential to the production process, it is important to quantify the amount of raw material available in the silo to ensure continuous production.