Sampling grid density test identification in the peat bogs

Layered peat samples (0.25 m) were selected at the deposit by a manual peat drill, including the determination of peat ash content, its decay rate and vegetation composition analysis. The above-mentioned factors are evaluation parameters to determine the peat type and its category for further application in agriculture. Vegetation composition of the peat is only used to determine its type (terrestrial, transitional and lowland). To study the different valuable raw peat types (bituminous, bedding, thermo- and noise-isolation materials and others), it is necessary to determine not only the peat type, but also its category. Statistic estimation of peat reserves is applied at the peat deposit exploration. In this case, the peat volume is distributed in proportion of the peat type category to the number of layered peat samples where the following estimation parameters are applied - ash content, decay rate and peat vegetation composition (type). The sampling grid density depends on the geological exploration stages. Each reserve category is depicted as a diagram in accordance with the maximum variation coefficient of one estimation parameter: either ash content or decay rate. To analyse the sampling grid density the sequential rarefaction method was used. In all initial samples at each stage not only the average peat ash content and decay rate, but also their variation coefficients were determined. The determination of the value of error (%) of these parameters to their initial mean was further calculated. It was noted that the peat ash content variations and decay rates practically do not depend on the peat deposit type. The variation coefficients of these parameters change more intensively than their average value during the sampling grid rarefaction. Of the two applied parameters in determining sampling grid density, only peat ash content is quite variable. Generally, the average peat ash content and decay rate, as well as their variation coefficients, change insignificantly during the sampling grid rarefaction. The existing determination method of sampling grid includes only the value, but not the variation mode of the peat ash content and decay rate. Such parameters increase towards the depth of peat deposits. Thus, sampling grid density cannot be determined by variation coefficient values of peat ash content and decay rate. However, it could depend on the number of identified stratigraphic areas of the deposit, where the number of sampling points must be identical regardless of the area itself. Vegetation composition variation was studied at the type level according to the sampling grid rarefaction. The following hypothesis was considered - partial selection to complete selection α = 0,05. The obtained data showed that at 50% of the examined deposits the peat vegetation composition changes insignificantly even at the type level. Thus, there is weak ash content variation, decay rate and vegetation composition at peat deposits, which, in its turn, creates the conditions for sampling grid rarefaction as compared with the existing method in nowadays exploration

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