Assessment of the woody plant species vital condition distributed on the devastated lands of the iron ore dump

The actuality of the research is caused by the importance of understanding the laws of natural distribution of woody and shrub plant species on devastated lands of iron ore dumps of Kryviy Rih as a theoretical prerequisite for harmonizing the ecological environment of industrial regions. The aim of the research is to assess the current vital condition of woody and shrub plant species that naturally grow on devastated lands of the iron ore dump from the standpoint of the ecosystem approach. The materials of the work were the results of our own research, which were carried out according to generally accepted methods during 2020–2021 on the territory of Petrovsky waste rock dump of Kryviy Rih iron ore basin. The assessment of the current vital condition was carried out according to the method of V. A. Alekseyev. Presently, the vegetation on Petrovsky waste rock dump, which is a model for the region, is represented by natural groups, has a fragmented character and is a sparse forest. It has been established that 32 species of woody and shrub plant species (25 genera and 15 families) naturally grow within Petrovsky waste rock dump. The current vital condition of woody and shrub plant species in the dump was assessed as «weakened» (65–71 conventional points by V. A. Alekseyev’s scale). Such numerical values of the vitality of the forest stand are 21–28% lower than the control indicators (natural groupings of Gurivka forest). Our results indicate that the ecological conditions of the devastated lands of Petrovsky waste rock dump are relatively favourable for the growth and development of woody and shrub plant species. It was found that European birch (Betula pendula Roth.), ash-leaved maple (Acer negundo L.) and acacia (Robinia pseudoacacia L.) are quite adapted to the habitat conditions of the dump. The vital condition of these species was assessed as «healthy»: 90–95 conventional points by V. A. Alekseyev’s scale.

Study of the parameters of spontaneous fire seats in coal pit rock dumps

The presence of coal and coal-bearing rocks in waste rock dumps of open-pit coal mines contributes to the occurrence of spontaneous combustions that negatively affect the environment and people. Measurements of the temperature and the content of hazardous gases in the temperature anomaly that arose in the waste rock dump of the open-pit coal mine were made to assess the parameters of spontaneous fire seats. In the course of the study, the efficiency of detecting spontaneous fire seats in waste rock dumps was assessed by measuring the rock temperature in the wells with a depth of 2.5 m, drilled at a distance of 20 m from each other. The experiment showed the difficulty of drilling control wells in waste rock dumps and the impossibility of drilling them on the slopes of dumps, especially in spontaneous fire seats with a high rock temperature. The necessity of casing control wells with pipes makes it difficult to measure the rock temperature at different depths. It was found that there are sharp drops in the rock temperature in the heated area of the dump, which cannot be detected when the wells are located at the recommended distance. The measurements showed that in all wells the temperature increases with depth, therefore the depth of wells recommended by the regulatory documents does not allow determining the size of the heated area.

Macronutrients and heavy metals contents in the leaves of trees from the devastated lands at Kryvyi Rih District (Central Ukraine)

This research was performed at Petrovsky waste rock dump, the Central part of the Kryvyi Rih iron-ore & metallurgical district (Dnipropetrovsk region, Ukraine). The macronutrients (K, Ca, Mg, P and S) and heavy metals (Fe, Mn, Zn, Cu, Pb and Cd) contents in the leaves of three species of the trees (Ash-leaved maple, Silver Birch and Black locust) that were collected on devastated lands were assessed. It was established that trees which grow on the Petrovsky dump take place under evident shortage of nutrients (especially K and P) and excess of metals (especially Fe, Mn and Zn). It is revealed that Ash-leaved maple and Black locust are more resistant to the geochemical conditions of devastated lands. In this regard, these species of trees can be recommended for forest restoration & reforestation on devastated lands.