In order to guarantee the highest possible level of consistent quality over long periods of time, the companies comprising Stephan Schmidt Group have implemented a comprehensive quality control system for their raw materials.
Initial evaluation of the different clay varieties is already performed during exploration drilling at the respective deposits. We take regular channel samples of the clays being mined at our quarries. In most cases, an automatic device draws the samples from the flow of material coming out of the quarry on a belt-conveyor.
The parameters derived from the representative average samples are used to adjust the individual mixed-clay compositions destined for production at the different homogenisation plants. The standardised raw material mixtures are produced by means of modern interspersing systems in large covered storage boxes. During this production process, representative samples of every single production lot are again taken and divided by automatic devices. After each customer's parameters of first priority have been analysed, the standardised clay mixture is released for shipment.
For many of our standardised raw material mixtures, we issue certificates that show the essential technical data assessed for a particular production lot in order to safeguard our customers' production processes.
All companies belonging to Stephan Schmidt Group are certified according to ISO 9001:2015.