Tunel drogowy w Lalikach został wykonany w silnie niejednorodnych, w dużym stopniu zniszczonych tektonicznie i w przeważającej części bardzo słabych utworach fliszowych Karpat Zachodnich. W przeważającej części tunel był drążony w warunkach dużego udziału procentowego bardzo słabych łupków ilastych laminowanych i utworów strefy zwietrzelinowej, niekorzystnego, bardzo stromego nachylenia warstw skalnych i zmiennego zawodnienia z wypływami wody w rozluzowanych strefach tektonicznych. Górotwór ten charakteryzuje się dużą niepewnością rozpoznania jego właściwości i struktury. Praca omawia wpływ warunków geologiczno-inżynierskich i geotechnicznych na dobór parametrów obudowy wstępnej tunelu drogowego. Przeprowadzono analizę deformacji obudowy wstępnej w zależności od procentowego udziału piaskowców i łupków, punktacji klasyfikacji geomechanicznych RMR (Bieniawski 1989) i QTS Tesařa (1979), typów obudowy wstępnej oraz wykorzystania kotew i mikropali. Analiza ta została poprzedzona charakterystyką warunków geologiczno-inżynierskich na trasie tunelu oraz charakterystyką typów zastosowanej obudowy wstępnej. W trakcie drążenia tunelu z wyprzedzeniem w kalocie, kilkakrotnie występowały przemieszczenia obudowy wstępnej kaloty większe od projektowanych maksymalnych. W przypadku, gdy wartości deformacji osiągały stan alarmowy dla danego typu obudowy i nie wykazywały tendencji do stabilizowania się, podejmowano decyzję o jej wzmocnieniu dodatkowymi kotwami, siatką oraz torkretem do czasu osiągnięcia stabilizacji deformacji. W najtrudniejszych warunkach obudowa wstępna była wzmacniana parasolem mikropalowym. Parametry obudowy dobierano, zgodnie z zasadami NATM, na podstawie prowadzonych na bieżąco obserwacji geologiczno-inżynierskich i geotechnicznych. Tunel w Lalikach jest przykładem bardzo słabej samonośności górotworu. Obserwowane przemieszczenia w górotworze wskazywały, że strefa spękań wokół wyrobiska była stosunkowo silnie rozwinięta. Obudowy wstępne stosowane w tego rodzaju warunkach, na niewielkich głębokościach, powinny charakteryzować się stosunkowo dużą nośnością. Doświadczenia, jakie uzyskano wskazują, że realizacja obudowy wstępnej w silnie zmiennych warunkach fliszu karpackiego wymaga prowadzenia szczegółowych badań geologiczno-inżynierskich w trakcie drążenia tunelu, które należy wykonywać na bieżąco wraz z postępem dobowym dla weryfikacji założeń projektowych. W przypadku potrzeby należy zastosować wzmocnienia obudowy wstępnej na podstawie wyników właściwie prowadzonych pomiarów geotechnicznych zachowania się układu obudowa-górotwór.
W publikacji przedstawiono wybrane wyniki badań laboratoryjnych dotyczące ograniczania dopływu wody złożowej do odwiertów wydobywczych gazu i ropy. Przeanalizowano wpływ nasycenia wodą gazonośnych utworów miocenu z rejonu zapadliska przedkarpackiego na ich przepuszczalność względną dla gazu. Dokonano przeglądu literatury pod kątem oceny rezultatów uzyskanych w zabiegach zmniejszania przepuszczalności względnej skał gazonośnych i roponośnych dla wody. Na podstawie testów laboratoryjnych dokonano próby oceny skuteczności zmian przepuszczalności względnej dla solanki i azotu próbek piaskowca szydłowieckiego pod wpływem oddziaływania czterech wyselekcjonownych produktów chemicznych w postaci polimerów oraz mikrożeli. Badania laboratoryjne wykazały, że trend zmian przepuszczalności jest również silnie powiązany z zastosowanym produktem - modyfikatorem przepuszczalności względnej (RPM). Ponadto, skuteczność działania cieczy zabiegowej zależy od prędkości przepływu (wydatku przepływu) solanki przez testowaną próbkę skały - skuteczność działania testowanego preparatu jest tym większa, im wydatek przepływu solanki jest mniejszy. Wyniki testów wykazały selektywne działanie badanych produktów. W przypadku produktu nr 1 uzyskano średnie spadki przepuszczalności na poziomie 60% dla solanki oraz 18% dla gazu. W przypadku zastosowania produktu nr 2 opartego na technologii mikrożeli zaobserwowano znaczące obniżenie względnej przepuszczalności skały dla wody, z małym wpływem na przepuszczalność dla węglowodorów. Zmiany przepuszczalności dla solanki testowanych próbek piaskowca zawierały się w przedziale od 65 do 90%, a dla gazu wynosiły około 50%.
This article presents the results of studies assesing the significance of the most important macro- and microeconomic factors affecting investors’ propensity to invest in mining. The Polish mining industry in recent years has seen intensive restructuring processes which have considerably affected the status of fixed assets required for the exploitation of useful minerals. In order to efectively manage technological progress in mining plants, it is necessary to understand the role of individual, variable factors influencing investors’ propensity tomake specific expenditures. In the analysis, mathematical statistics and econometric modelling methods were applied to determine the nature of correlations between the values studied and their significance. This examination applied statistical data accumulated by economic entities from 2000–2010. A linear econometric model waspresented illustrating the relationship between capital expenditure in mining and such indicators as fixed assetsvalue, GDP, real interest rate, consumption levels of fixed asset components in mining, and various other factors. Structural parameters of a function specifying the level of investment expenditure can be determined based on statistical data which has been appropriately processed so that the model constructed reflects the economic process studied in relevant way.
Such a model is not free of defects typical in statistical models; however, it simultaneously enables one toobtain valuable information concerning the impact of the factors studied on the value of such expenditure, and the theoretical possibilities to exchange the specific quantity of one factor for another factor. In the final version of the model, it is often sufficient to include only these independent variables which contribute the most essential information to the independent variable. This often simplifies the final form of the model without simultaneous limiting of its importance in explaining the economic phenomenon studied and the possibilities of its practical application. In the final selection of significant variables captured in the model, the method of information capacity indicators was used.
This article concerns the issues of modeling and the optimizational approach for the performance of ore comminution circuits. A typical, multi-stage comminution circuit was analyzed with the high-pressure grinding rolls unit operating at a fine crushing stage. The final product of the circuit under investigation was, at the same time, a flotation feed in which particle size distribution initially determined the effectiveness of flotation operations. In order to determine the HPGR-based comminution circuit performance, a suitable mathematical model was built wherein the target function was linked directly with the effectiveness of the flotation processes. The target function in the presented model considers the issue in terms of the flotation operation’s effectiveness. The particle size distribution of individual comminution products and resulting from the weight recoveries of individual size fractions were criteria determining the quality of the comminution product. Weight recoveries of individual size fractions, in turn, were tied with the technical operating parameters of individual comminution devices. In the first model, profit maximization was the target function, while the second variant of the model took into account maximization of the useful mineral weight recovery in the concentrate. The HPGR application into ore processing circuits also results in energy saving benefits which were presented in a comparative analysis of the energy consumption of two comminution circuits – the first based on conventional crushing devices, and the second on the HPGR unit application which replaced the rod mills. The main benefit of such a modernization was almost two times lower energy consumption by the fine crushing stage and a decrease in the ball mills’ grinding operations load through bypassing a part of the material directly for the rough flotation operations.
The paper concerns the accuracy of determining particle size distributions of the fine-grained materials by means of laser diffraction method. Selection of measuring method for determination of materials granulation depends on various properties of the sample, but mainly on the range of particle size in the sample. It must be taken into consideration that each of the measurement methods inherently generate different information about particle size distribution. The applied measurement method generates the main impact on the results of research because it uses various material properties, like: geometric properties, density or type of the surface (porosity).
Influence of density and particle shape on the results of measurements by laser diffraction was studied in the paper. This method becomes a standard for measuring particle size of mineral powders. Analysis of raw materials particle size distribution was performed using a laser particle-meter Analysette 22. Investigations included measurements of particle size of raw materials characterized by various densities (coal, porphyry, barite) and the shape of the particles (copper shale ore, fly ash from coal combustion). The density of raw materials was determined by helium pycnometer, while the particle shape was expressed by coefficient which was calculated on the basis of particles geometric parameters. Geometry of the grains was measured using an optical microscope with a digital record of images by means of image analysis method. The accuracy of laser granulometric analyzes was expressed by variation coefficient of narrow particle fractions contents. Results of analyzes confirmed that the laser granulometric analysis provides accurate information about the finestparticle size distribution. No significant effect of the material density on the accuracy of granulometric analysis was observed. Effect of particle shape of the tested materials caused more stable values of the variation coefficient for particles of more spherical shape what is related to the applied method of laser measurement. The accuracy of laser granulometric analyzes varies dependably on the measured particle size range of particles. The most accurate analyzed materials are these ones being the part of narrow particle fractions.
Anisotropy of variations of Polish mineral deposit parameters is rarely the subject of interest of geologists who carry on the assessment projects . However, if the anisotropy is strong its description and mathematical modeling are rational and justified as it may affect the accuracy of many calculations suitably for mining geology and mining engineering, e.g. estimation of resources and grade of particular raw-material, interpolation of deposit parameters values and construction of their contour maps, designing of optimum grade mining operations or densification of sampling grid. In geostatistics anisotropy is described with directional semivariograms which represent average variability of values of particular deposit parameter in various directions, depending on the distance between sampling sites. Convenient graphic presentation of anisotropy is map of directional semivariograms and good mathematical presentation are functions describing the anisotropy models.
The paper presents the results of geostatistical descriptions of various anisotropy types in selected examples of Polish mineral deposits. Taking into account the spherical variability model, the influence of anisotropy on the results of deposit parameters estimations has been theorized for both the interpolation point and calculation block (area). It was found that anisotropy is effective for parameters estimation if three mutually interrelated factors are considered: power of directional diversification of parameters variation, contribution of random component to total, observed variation of parameters and the range of semivariograms (autocorrelation) of parameter referred to the average sampling grid density.
The results demonstrate that anisotropy influences much more the estimations of parameters value in interpolation points than those of average values of parameters calculated for particular parts of deposit (calculation blocks). Moreover, anisotropy is unimportant when the random component of variability dominates the overall variability of analyzed parameter. Therefore, the simpler, isotropic variability model can be applied to geostatistical estimations of deposit parameters.
The subject of the research was the Middle Miocene red algal limestone from the Włochy deposit, which is currently the only place of exploitation of the Pińczów Limestone representing a local type of the Leitha Limestone. The collected samples of this rock belong to the organodetric facies of diverse grain size and sorting of clastic material. Considering the proportions of characteristic skeleton remains, the composition of the coarse-grained organodetric facies is red algal-foraminiferalbryozoic, while of the fine-grained facies is foraminiferal-red algal. The cement of these rocks is predominantly sparite compared to micrite-clay matrix. A complement to petrographic studies was the chemical analysis and identification of mineral phases with X-ray diffraction. Moreover, physical and mechanical properties of samples were analyzed. Porosity of the rock was assessed in the polarizing and scanning microscope (SEM-EDS) observations, as well as with a porosimetric tests. The coarse-detrital limestone with a dominant binder in the form of intergranular cement is characterized by the apparent density sometimes exceeded 1.90 Mg/m3, while fine-grained limestone has the highest water absorbability (above 20%) and total porosity (about 40%). The above properties influenced high water absorption by capillarity, limiting the possibility of using limestone in places exposed to moisture. The observed relationship between the ultrasonic waves velocity and the uniaxial compressive strength gives the possibility of predicting the value of the latter parameter in the future. The limestones from Włochy deposit do not differ in quality from the previously used Pińczów Limestones, and their technical parameters predestine them for use as cladding material with insulating properties.
The research was aimed at examining the impact of the petrographic composition of coal from the Janina mine on the gasification process and petrographic composition of the resulting char. The coal was subjected to fluidized bed gasification at a temperature below 1000°C in oxygen and CO2 atmosphere. The rank of coal is borderline subbituminous to bituminous coal. The petrographic composition is as follows: macerals from the vitrinite (61.0% vol.); liptinite (4.8% vol.) and inertinite groups (29.0% vol.). The petrofactor in coal from the Janina deposit is 6.9. The high content of macerals of the inertinite group, which can be considered inert during the gasification, naturally affects the process. The content of non-reactive macerals is around 27% vol. The petrographic analysis of char was carried out based on the classification of International Committee for Coal and Organic Petrology.
Both inertoid (34.7% vol.) and crassinetwork (25.1% vol.) have a dominant share in chars resulting from the above-mentioned process. In addition, the examined char contained 3.1% vol. of mineroids and 4.3% vol. of fusinoids and solids. The calculated aromaticity factor increases from 0.75 in coal to 0.98 in char. The carbon conversion is 30.3%. Approximately 40% vol. of the low porosity components in the residues after the gasification process indicate a low degree of carbon conversion. The ash content in coal amounted to 13.8% and increased to 24.10% in char. Based on the petrographic composition of the starting coal and the degree of conversion of macerals in the char, it can be stated that the coal from the Janina deposit is moderately suitable for the gasification process.
This investigation is concerned with the extraction of nugget copper particles from copper recovery plant slag which recycled of copper scrap. For this purpose, the Falcon concentrator was used because of its enhanced gravity properties. The Falcon concentrator has a fast spinning bowl which creates a centrifugal force to separate fine size minerals on the basis of their density differences. In the tests, the tailings of the copper recovery plant were used and the test sample was divided into two groups and one of them was classified in narrow particle sizes. The operational parameters were determined as particle size, centrifugal force and washing water pressures. The water pressure and centrifugal force have an inversely proportional relationship. Because of this phenomenon, the G/P parameter was created. The test conditions were applied to the whole distribution sample and narrow size distribution samples in the same way.
The test results indicate that the average grade was elevated from 1.04% to 6.50% with the recovery of 15.07% and 619% enrichment ratio for narrow sizes, whereas grade was elevated to 4.36% with 13.24% recovery and 415.94% enrichment ratio for the whole distribution. As a result, the recovery and grade values of concentrates are not good enough for gravity concentration process for both samples. However, this process was applied to the double recycled material and the lower recovery, grade values can be tolerated because of concentrate is nugget copper metal. The concentrate can also be washed in cleaning table for increasing the grade value for adding to initial feed of plant. This process can, therefore, supply important earnings not only economically but also environmentally.