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Based on the uniform strength and minimized stress intensity factor, the maximum strength shape of an opening in rock mass is theoretically analyzed. The criterion and solution method are proposed for the problem on prevention of failure in rock mass with opening under the action of tectonic forces and gravity. The constructed closed system of algebraic equations enables minimization of stress intensity factors depending on mechanical and geometrical parameters of rock mass.

The results of numerical modeling of intense shock wave propagation after explosion in a mine opening with permeable barrier are presented. The problem is solved in the equilibrium inviscid formulation without regard to chemical reactions and with averaged composition of mine air. It is shown that for a screen composed of four similar permeable barriers arranged as a labyrinth, the incoming shock wave has a strongest impact on the first barrier. As a consequence of weakening of the shock wave front on the first barrier, the rest barriers experience much less loading. In order to decrease peak loads on a load-bearing metal structure, it is necessary to reduce areas of their flat front surfaces.

In order to meet the increasing demand to coal, longwalls having large working heights up to 7.3 m are being operated worlwide. As the working heights increase, the load-bearing capacities of powered roof supports used at such longwalls are to be raised too. From a powered roof support it is expected that it safelybears the roof loads and transmits them to the footwall at different working heights. This article presents the results of numerical analyses on roof stresses at different longwall working heights. In order to determine the most suitable longwall working height, average stress distributions that occur on roof and gob zones are calculated for different longwall working heights. For this purpose, numerical models are built up and the procedure is applied to a real-life underground coal mine. Six distinct longwalls are modeled considering rock mass properties and working heights. In conclusion, the most suitable longwall working height for the mine under study is determined considering stresses occurring on roof strata and the gob zone.

The determination of the grain size distribution of blasted rock exceeds the capability of an analytical sieving machine which only gives reliable results within a range of 63 µm to 125 mm. Other sophisticated methods are often not available for particle size measurement in coarse-grained applications in medium scale mining. Therefore, an alternative low cost method to investigate the grain sizes of blasted rock is introduced which can cover a range from 63 µm at the lower end without an upper limit. Three different options to examine blasted dolomite grains are investigated and combined with sieve analysis to determine a complete sieving equivalent grain size distribution. Comparison with results of a technical sieving shows that this method gives a good approximation of the size distribution, improving the possibilities for design of mineral processing equipment.

Accuracy of breakstone grain-size analysis using digital images in the initial method and its modification based on algorithm proposed by Rubin is compared. A modification with averaging of features over all directions and the method with a classification feature represented by difference of intensity distribution functions of fragment projections are described. The results obtained using these methods in a series of tests on grading of five breakstone fractions measured in a certified laboratory. It is shown that the modified method by Rubin with averaging over all directions provides the highest accuracy.

In a transportation fleet in open-pit mines, the match factor is defined between loading and dumping vehicles. This factor helps in indicating the number of vehicles that depend on each other. In this study, a new parameter termed the “detailed match factor” is developed to improve the transportation fleet and relationships are deduced to control the production and grade. A transportation fleet model was simulated for a typical iron ore mine and was solved using both the detailed match factor and ant-colony algorithm methods. The detailed match factor helped in increasing the production by 10.6%

Using inverse distance weighting (IDW), the model of a coal seam with distributed geological and geomechanical characteristics is developed. The hyperbolic dependences of the cutter-loader advance feed and capacity on the coal seam thickness are found. Influence of coal face spalling on cutter-loader capacity is assessed. Using the specialized library of MTSS, the integrated model of process flows in coal face area is developed. It is found that there exists cutter-loader capacity maximum at the increasing dependence of coal cuttability on longwall length.

Backfilling mixture preparation technology using a cement-slag binder is developed for Artem mine. It is shown that backfill with granulated blast-furnace slag reaches project strength when slag is to 80% milled down to 80 μm. The authors analyze influence of milling fineness of granulated blast-furnace slag from different manufacturers on strength and rheological properties of backfill. The economic analysis of cost of binder in formation of load-bearing layer of backfill prepared using fly ash and milled granulated blast-furnace slag is performed.

Various-rank tectonic structures are distinguished in the Norilsk Region. The first-order block structure is formed by intersection of rank I geodynamically active faults: Khatanga, Imangda-Kystykhtakh, Norislk, Fokin-Tangaralakh and other. Rank II faults are the Norilsk-Kharaelakh fault, which intersects the mine field, and other 7 structures. Using geological sections and boring records obtained within the mining lease, dip slips and oblique-slip faults of rank III, represented by ridges in the terrain, are plotted in the satellite image. In the rockburst-hazardous high-grade ore sites in Glubokaya mine, it is recommended to make safe zone by advance boring of destressing holes in underground openings in zone of rank III faults.

Predicting the consequences of changes in a system such as the system of exploitation and consumption of limestone is a problem that requires an adequate analytical approach and encompasses all the limiting factors, their performance, dependence, desirable and non-desirable changes, and completion of the set goal or multiple goals. Without forming the mathematical model and applying the adequate solving method, it is not possible to solve the problem on the optimal level. This paper shows the linear model of location exploitation optimization and consumption of limestone in Macedonia, with 29 production entities - open-pit mines, and two options of consumption entities, with 15 and 16 lime consumers. By changing one of the starting presumptions, the number of consumers, the research shows that mathematical model approach with adequate sensitivity to changes of relative parameters is necessary for a complete and reliable overview of system behavior.