This publication presents the research aimed at developing statistical models, on the basis of which it was possible to prepare credible forecasts of unit cost and coal net output for longwalls in 5 hard coal mines in P oland. The argument has been verified that there is a dependence between the level of nuisance and the level of costs, as well as longwall production results.

A research procedure has been developed for that purpose, which aimed at developing two statistical models connecting the nuisance due to geological and mining conditions with costs and longwall production results. The multiple linear regression technique has been used to develop statistical models. The set of data taken into account in the analyses comprised 120 longwalls mined in the years 2010–2019. Two models have been developed – one for forecasting unit costs, the other for forecasting coal net output. Subsequently, the models’ forecasting ability has been verified on a sample of historical data. A relative forecast error for 75% of observations has been in the range of (–25%; +37%). That result has been considered satisfactory. Subsequently, using those models, forecasts of unit costs and coal net output have been prepared for 220 longwalls planned for mining in the years 2020–2030. Those forecasts have been prepared in the stipulated ranges of geological and mining nuisance influencing mining process, by means of dedicated W Ue and W Ut factors. The nuisance models for forecasting purposes have been developed using the AHP (Analytic Hierarchy Process) method. The research hypothesis has been confirmed on the basis of the obtained results. An increase in the level of nuisance leads to an increase in the unit costs for longwalls and the deterioration of production results. Unit operating costs for longwalls in specific ranges of nuisance may differ by up to 30%, being in the range of 52.0–120.3 zł/Mg. Likewise, the coal daily output of longwalls may be even 22% lower, having the average level in the range of 1.89–3.61 thousand Mg/d.

Evaluations of odour intensity of the air polluted with cyclohexane (A), cyclohexanone (B) and cyclohexane with admixtures of cyclohexanone (mixtures MI, M2 and M3; x8 = 0.14; 0.05 and 0.02 respectively) were made. Empirical parameters of psychophysical equations (Weber-Fechner' and Stevens') were determined. Total concentrations of the mixtures were within the range C = 1500-3500 ppm. The interaction constant av= 115-132° was estimated for the mixtures. Verification of known models of odour interaction led to the conclusion that possible application of the models for prediction of odour intensity of the air polluted with mixtures of cyclohexane and hexane is limited.

This article presents the use of a multi-criterion Analytic Hierarchy Process (AHP) method to assess

geological and mining condition nuisance in longwall mining operations in selected coal mines in Poland.

For this purpose, a methodology has been developed which was used to calculate the operational nuisance

indicator (WUe) in relation to the cost of mining coal in individual longwalls. Components of the aggregate

operational nuisance indicator include four sub-indicators: the natural hazards indicator (UZN), an

indicator describing the seam parameters (UPZ), an indicator describing the technical parameters (UT)

and an environmental impact indicator (UŚ). In total, the impact of 28 different criteria, which formed

particular components of the nuisance indicators were analysed. In total 471 longwalls in 11 coal mines

were analysed, including 277 longwalls that were mined in the period of 2011 to 2016 and 194 longwalls

scheduled for exploitation in the years 2017 to 2021.

Correlation analysis was used to evaluate the relationships between nuisance and the operating costs

of longwalls. The analysis revealed a strong correlation between the level of nuisance and the operating

costs of the longwalls under study. The design of the longwall schedule should therefore also take into

account the nuisance arising from the geological and mining conditions of the operations. Selective

operations management allows for the optimization of costs for mining in underground mines using the

longwall system. This knowledge can also be used to reduce the total operating costs of mines as a result

of abandoning the mining operations in entire longwalls or portions of longwalls that may be permanently

unprofitable. Currently, underground mines do not employ this optimization method, which even more

emphasizes the need for popularizing this approach.

The paper presents new differencing algorithms for post-processing GPS data, using double or triple carrier phase differences and multiple baseline sessions. The characteristic feature of the new algorithms is, that they use full sets of Schreiber's type observation differences with theoretically proved diagonal weight matrices. The proposed estimation models are equivalent to the least squares estimation applied to the original system of un-differenced observation equations. The theoretical ground of the algorithms are the theorems on the properties of differencing equations of Schreiber's type. The theorems become practically useful mainly in case of functional models with triple-differences. In a classical approach, this task was simplified for the sake of necessity of inverting non diagonal covariance matrix, usually of a large dimension. Diagonal weight matrix is also obtained in case of multiple point observation session where correlation of the GPS vectors forces in practice the use of the simplified stochastic models. The proposed method eliminates also the problem of selection of a reference satellite. It is very important especially in case of long observation sessions. The algorithms are applied in professional software for GPS relative positioning.