Optimal resources utilization, reduced land requirement

Germany’s Ministry of the Environment is supporting a pilot project of the company Westkalk with around € 150 000 from the Environmental Innovation Programme. With this funding, the Ministry is recognizing Westkalk’s endeavours to more efficiently remove impurities from the ­limestone extracted at its Kallenhardt quarry and to utilize resources more sparingly. With a new combination of trommel screen and primary crusher (Fig.), Westkalk aims to improve utilization of the rock to over 90 %. The average annual land requirement of the quarry is to fall by 20 % at the same time. Westkalk’s pilot project therefore contributes to improved raw material utilization and a considerable reduction in the land required. With the Environmental Innovation Programme, Germany’s Ministry of the Environment is promoting the first, industrial-scale application of an innovative technology. The funded project must go beyond the state of the art and have a demonstration character.

The new trommel screen and primary crusher for Kallenhardt quarry are manufactured and supplied by the machinery manufacturer Hazemag. In future, the combination of the two machines is to effect improved separation of limestone and loam components: the loam-containing substances are first comminuted and then screened out. The pre-screened material is then processed in the rock-washing plant to recover the limestone contained. Thanks to the improved separation of valuable rock and overburden, even blasted material mixed with considerable loam can be transported to the primary crusher. This reduces the proportion of valuable rock on the waste heap from around 30 to below 10 %. The high utilization of the deposit leads to almost optimum resource efficiency.

The new primary crusher and trommel screen, which have been subsidized with around € 150 000, are not the only investments that Westkalk is making in this connection. A two-storey, around 500-m-long belt conveyor from the new site of the primary crusher in the quarry to the preparation plant as well as a new high-grade chippings plant in which the rock is re-crushed and sized are also to be installed. Westkalk is paying out a total of € 7.5 mill. for these new installations. The building work is set to commence in the next months following conclusion of the building permission process.