Stones, sandpits and limestone quarries in the Czech Republic

Properties of mineral resources of the same type may vary significantly, depending not only on the quarry in which they are mined, but also on the specific sampling point within one extraction area. For example, the differences in compressive strength of sedimentary rocks (e.g. sandstones) in the same quarry normally reach tens of percent. It was beyond our limits to perform a detailed survey of the quality of mineral resources in all operating quarries and therefore the sampling procedure was chosen as described below.

Samples of decorative stones for determination of chemical composition and physical properties were prepared by stone quarry operators. From a petrographic point of view, the samples should be homogeneous and represent stones of high-quality, although commonly found in the quarry, i.e. not rare stones. In some cases the stone samples were taken out of current production by the personnel of the Research Institute of Inorganic Chemistry during their quarry visit after consulting the quarry operators. Sample non-homogeneity, documented as a rule by abnormally high standard deviations of the measured parameters, was discovered only rarely by visual inspection and/or based on the test results. In such cases the results were commented.

Limestone samples were taken by the personnel of the Research Institute of Inorganic Chemistry in cooperation with quarry operators who chose the sampling site in accordance with their experience to make sure that the chemical purity of the limestone would be as high as possible, but that the limestone would be readily available, at the same time.

In sandpits, samples were taken by the personnel of the Research Institute of Inorganic Chemistry from current production. Sampling of pit (unwashed) sand with the grain size distribution fraction of 0–4 mm was preferred. If sampling was performed using another method, which happened only rarely, this fact was commented in each case.