The article describes the influence of anomalous values and local variability on the structure of variability and the estimation of deposit parameters. The research was carried out using statistical and geostatistical methods based on the Pb accumulation index in the shale series in part of the Cu-Ag ore deposit, LGCD (Lubin-Głogów Copper District). The authors recommend the use of a geostatistical tool, the so-called semivariogram cloud to determine the anomalous values. Anomalous values determined by the geostatistical method and removed from the dataset have resulted in a significant reduction of the relative variability of data, which is still very large in the case of the analyzed parameter or parameters with similar statistical features such as extreme variability and strongly asymmetric distribution. Calculations of the resources of this element can be treated only as estimates and formally classified to category D. The hypothetical assumption of the absence of sampling errors, resulting in a decrease in the magnitude of local variation, leads to a certain reduction of the median error of resource estimates. However, they are still high (> 35%). This is due to the large natural variability of the accumulation index of Pb on the local observation scale. The current method for collecting samples from mine workings of the Cu-Ag deposits in the Lubin-Głogów Copper District (LGCD), aimed at the proper assessment of copper resources, the Cu content, and at estimating the quality of copper output, makes it impossible to achieve an accuracy of estimates of Pb resources similar to that obtained for the main metal. Theoretically, this effect can be achieved by a strong concentration of the sample collection points and thanks to a multiple increase in the samples weight; this, however, is unrealistic for both economic and organizational reasons. It is therefore to be expected that the assessment of Pb resources and other accompanying elements of similar statistical features (e.g. As), located in parts of the deposit where mining activities are to be carried out, will be subject to significant errors.

The selection of appropriate financial sources by enterprises is one of the key tasks faced by the management board. In the presented article, the Authors decided to verify the capital structure of companies from selected European economies and to compare this capital structure between developed and advanced developing markets. The research was conducted on 18 European economies, taking into consideration data for 2017 and five variables defining the structure of financing. The results of the analysis show that the economies in the basket of developed countries are characterised by a higher level of indebtedness, with the major difference in taking on interest-bearing liabilities.

The local aspect of aging is often ignored. However, municipalities, in particular cities will be affected by the consequences of population aging, in particular a decrease in tax revenues and an increase of expenditures on public goods demanded by the elderly. In this paper we use a static general equilibrium model to analyse the impact of aging on city’s finances. We show that an increase in the number of pensioners will raise the cost of public goods. However, an increase in the number of working elderly can alleviate the situation.

This article examines the influence of International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW 1978) on actual maritime workforce training system. The Convention is in constant development; the authors discuss 1995 and 2010 amendments as well as the European Union law context, namely the role of the European Maritime safety Agency in implementation of the Convention. The article analyses integration of STCW system into Polish law and uncover shortcomings and delay of this process. In conclusion, the authors recommend reinstatement of standardised master’s degree for deck department officers in Maritime University in Gdynia’s Faculty of Navigation in order to carry out the provisions of the Convention and connect theory to practice.

The occurrence of trace elements in coal and their concentration ranges are presented. The paper describes the origin of trace elements in coal, modes of accumulation, binding with mineral and organic matter as well as their behaviour during combustion. The presence of trace elements of coal origin should be taken into consideration when evaluating harmful impact of coal-fired fewnaces due to significant concentration of fly ash from combustion in suspended dust On the basis of analytical data emission of 15 trace elements from coal combustion in Poland is presented.