The largest limestone plant of the African company produces a million tons of quicklime a year. The quality requirements are high – the silicate content must be under one percent. 75% of the deposits is a low-grade quality limestone. Those parts which do not meet the product specification have until now been disposed of at a large waste rock dump. However, 60% of this wasted material consists of high grade limestone. This has been a loss in two respects. On the one hand, work and energy has been expended to mine these limestone deposits and, on the other, valuable raw material has remained unused.
The lifetime of the mine has doubled
With the installation of a TOMRA Sorting Solutions machine Idwala Lime took multiple steps towards increasing its production efficiency. Optical sorting now allows limestone to be extracted from the previously discarded layers of low-grade limestone. The sorting plant has thus significantly increased the limestone reserve in so far as the lifetime of the mine has doubled. Nowadays less material needs to be mined in order to obtain the same quantity of quicklime, the final product. As a result, the production facility has improved significantly and the amount of waste rock to be hauled and dumped has also halved.
The greater yield through the use of sensor-based sorting machines does not only bring more profit, it also preserves the environment through the reduction of emissions and energy consumption. This is an excellent way to treat our Earth responsibly in the face of limited supplies of raw materials.