Abstract: The invention relates to the preparation of a material mixture consisting of a plurality of mineral raw material components which are delivered individually proportioned, are ground and homogenised, wherein samples are periodically analysed and determined ACTUAL values are compared with predetermined DESIRED values in order if appropriate to carry out corrective control interventions on the proportioning of raw material components by way of a laboratory computer. In relatively short time periods evaluations of the material samples and re-homogenisation of the ground mixture can be carried out very reliably with relatively low expenditure on construction if the material samples are analysed on the spot by means of a rapid analysis arrangement and the determined ACTUAL values from this analysis are passed to the laboratory computer, the homogenisation being carried out in a mixing zone with relatively small receiving capacity which is separated from the storage zone.

Abstract: The invention relates to a pneumatic-tube conveying installation in which a tube section accommodating the sample carrier at the despatch and receiving stations is designed to be tilted into a filling or emptying position about an axis extending transversely of its longitudinal axis. A conveying installation such as this is distinguished by its particularly simple construction and operational reliability.

Abstract: A pneumatic-tube installation for posting samples of fine material comprises at least one sample despatch station for filling, sealing and despatching sample carriers, a sample receiving station for receiving, emptying and returning the sample carriers to the sample despatch station and a pneumatic tube system connecting the sample despatch and receiving stations. When a carrier arrives at the receiving station it automatically is opened, emptied, reclosed, and readied for return to the despatch station at which it automatically is conditioned to receive a fresh sample.