This study introduces a new model to determine the critical flyrock event in mines. The flyrock was predicted and optimized using a field database including six parameters and 240 blasting events. ...The human learning optimization (HLO) algorithm was used in this research to optimize the support vector regression (SVR) function. Given different coefficients of kernels, optimization process minimized the likelihood of error in the models, allowing them to be detected and performed with the greatest precision. This procedure was repeated until the best model was discovered. Eventually, the radial basis function kernel was chosen for evaluating flyrock because it received the lowest computational error and the highest model accuracy. This model provided coefficient of determination (
R
2
) = 0.9372 and
R
2
= 0.9294, respectively, as the accuracy for training and testing results. This function was considered as a relationship that the HLO algorithm could use to find the best options (i.e., optimal condition) under various conditions. The findings for 14 cases that are the essential examples in this study indicated that the optimal states are found with a great precision. The variation of the results obtained from optimization with real values is less than 5%. This demonstrates that a suitable model can be developed by employing the HLO algorithm in the development of the predictive related models to blasting and rock mechanics.
The production of building stones shown an exponential growth in last decades as consequences of the demand and developments in the extraction and processing techniques. From the several conditioning ...factors affecting this industry, the geological constrains at quarry scale stands out as one of most important. Globalization and increasing competition in the building stone market require large raw material blocks to keep further processing as cost-effective as possible. Therefore, the potential extraction volume of in-situ stone blocks plays an important role in the yield of a dimensional stone quarry. The full characterization of the fracturing in the quarries comes up as fundamental in the assessment of the in-situ blocks volume/shape and potential extracted raw blocks. Identify the joint sets present, their spacing and the differences across the quarry demands a continuous assess during the quarry live span. Information from unmanned aerial vehicles helps in the field survey, namely trough digital surface models, orthophotos, and three-dimensional models. Also, the fracturing modelling by specific software programs is crucial to improve the block size assessment and the increase the quarry yield. In this research fracturing of twenty-one quarries of granite, limestone, marble, and slate from Portugal were assessed by combining field surveys with new techniques. From the studied quarries several cases were selected and presented to highlight the importance of this combined methodology in the fracturing assessment and how they can be helpful in the maximization of the resources and quarry management.
The aim of this study is to decipher the respective influences of geodynamic and climate disturbances at the Jurassic/Cretaceous boundary on sedimentary facies and carbonate diagenesis in a stable ...intracratonic basin using isotopic geochemistry and subsidence quantification. Fourteen lithofacies were deposited in a (1) carbonate platform and (2) a delta plain environment. Climate change from cool and wet to warm and semi-arid conditions during the early Tithonian influenced the syn-sedimentary dolomitization process within the carbonate platform during the mid-Tithonian. Architecture and facies reconstructions well-constrained the Jurassic-Cretaceous Unconformity (JCU), which was an important local structural episode marked by (1) an 80 m uplift in the eastern Paris Basin and by (2) the formation of a NW–SE low wavelength 15 km-wide and 30 km-long flexure. This first tectonic event tended to maintain brine ponds and supratidal marsh environments in the platform during the late Tithonian and early Berriasian, forming Purbeckian facies and associated dolomitic facies. A major depositional change occurred between the early and late Berriasian from shallow carbonate platform environments to fluviatile-deltaic clastic deposits (Wealden facies). This facies change is underlain by a major unconformity corresponding to the Ryazanian unconformity. It is marked (1) by erosion processes, karstification of the carbonate substrate, and the development of ferruginous weathering products (goethite), followed by (2) incision processes in a fluvial-deltaic environment. This unconformity is consecutive to a 40 m uplift in the eastern Paris Basin. The rifting phase in the Bay of Biscay, in the Pyrenean Zone, and in the Artic-North Atlantic together with the opening of the Ligurian Sea had a major influence on the northern part of France by causing uplifts (120 m from the Tithonian) and flexuring. Geodynamics played a major role in carbonate demise in the Paris Basin leading to exposure and karstification of the carbonate platform. Added to the generalized uplift, western Tethyan cool and humid conditions from the late Berriasian caused terrigenous influx into large-scale marine domains which was detrimental and unfavorable to carbonate growth.
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•Evolution of the Paris Basin platform throughout the Jurassic-Cretaceous boundary has been traced.•δ18O values of carbonates indicate an early sabkha dolomitization process from the early Tithonian to early Berriasian.•Geodynamics played a major role by causing a cumulative uplift of 120 m leading to emersion and karstification.•Carbonate platform demise occurred from the late Berriasian.•Western Tethyan humid conditions and terrigenous influx from the late Berriasian were detrimental to carbonate growth.
Elemental data from travertines are a treasure of depositional and diagenetic information. However, correct interpretation requires proper data acquisition and treatment. This study shows how results ...from elemental analyses complement sedimentological and other geochemical, i.e. isotopic, data and thereby contribute to our understanding of fossil travertines. Multivariate statistical element analyses, after multiple travertine digestion methods, demonstrate the link between elements, their mineralogical phases, and ultimately their origin. This study reveals that carbonate-phase related elements in travertines (Sr, S, Ba, Mg and Na) originate dominantly from the fluid source rocks. In combination with the δ18O and δ13C signatures, they are thus key geochemical variables for comparison of different travertine geobodies. Geochemical data analysis (elemental concentrations and isotope signatures), as illustrated here for the Turkish Ballık travertines, supports interpretation with regard to fluid source rock, distance from the vent and relative intensity of processes like evaporation and degassing. For fossil travertines, geochemical data can thus provide crucial insights for understanding the hydrologic system. In particular when information is restricted to borehole data, like in subsurface reservoirs, their application could be decisive.
•Multiple element comparisons of travertines require a standardised full digestion•Multivariate statistical analyses help to link elements to their mineral phase•Carbonate-phase elements (Sr, S, Ba, Mg, Na) originate from the fluid source rocks•Carbonate-phase elements and δ18O - δ13C are key for comparison of travertines•Geochemical data unravels vent proximity and evaporation-degassing intensity
The numerous trap rock quarries of northern Virginia have been a prolific source of macro- and micromineral specimens for many decades . Notably, they have produced world-class apophyllite, prehnite ...of superior color, and a wide variety of other minerals including the first finds of goosecreekite and loudounite, which are both named for Virginia localities. Unfortunately, the naming of the quarries in the Culpeper Basin, both in the literature and on specimen labels, is somewhat haphazard and confusing. A primary objective of this article is to give brief histories of the quarries, to resolve confusion regarding locality names, and to provide a summary of more than forty species found in them.
In this study, nine volcanic tuffs from Armenia, Germany and Mexico were treated with two commercially available consolidants on base of silicic acid ester, as well as different pretreatments with an ...anti-swelling agent and/or primer components. Prior to the treatment, the tuffs were analyzed regarding their petrography and mineralogy, with a greater focus on their clay mineral content. The effect of the consolidation was evaluated by comparative analyses of petrophysical properties and weathering behavior before and after the treatments. The main goals of this study were to identify a general suitability of different consolidating treatments for different types of tuff, evaluating tartaric acid as a primer component for tuff consolidation and to pursue the approach of finding a molecular answer for apparent tuff consolidation problematics, by testing a consolidation agent with smaller molecule sizes than current products on the market: tetramethoxysilane (TMOS).
A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives were rare and species-poor at low paleolatitudes throughout the Late Triassic Period, a pattern ...persisting 30 million years after their origin and 10â15 million years after they became abundant and speciose at higher latitudes. New palynological, wildfire, organic carbon isotope, and atmospheric p CO â data from early dinosaur-bearing strata of low paleolatitudes in western North America show that large, high-frequency, tightly correlated variations in δ ¹³C âáµ£g and palynomorph ecotypes occurred within a context of elevated and increasing p CO â and pervasive wildfires. Whereas pseudosuchian archosaur-dominated communities were able to persist in these same regions under rapidly fluctuating extreme climatic conditions until the end-Triassic, large-bodied, fast-growing tachymetabolic dinosaurian herbivores requiring greater resources were unable to adapt to unstable high CO â environmental conditions of the Late Triassic.
Significance This is, to our knowledge, the first multiproxy study of climate and associated faunal change for an early Mesozoic terrestrial ecosystem containing an extensive vertebrate fossil record, including early dinosaurs. Our detailed and coupled high-resolution records allow us to sensitively examine the interplay between climate change and ecosystem evolution at low paleolatitudes during this critical interval of Earth's history when modern terrestrial ecosystems first evolved against a backdrop of high CO â in a hothouse world. We demonstrate that these terrestrial ecosystems evolved within a generally arid but strongly fluctuating paleoclimate that was subject to pervasive wildfires, and that these environmental conditions in the early Mesozoic prevented large active warm-blooded herbivorous dinosaurs from becoming established in subtropical low latitudes until later in the Mesozoic.
Blasting is a common method of breaking rock in surface mines. Although the fragmentation with proper size is the main purpose, other undesirable effects such as flyrock are inevitable. This study is ...carried out to evaluate the capability of a novel kernel-based extreme learning machine algorithm, called kernel extreme learning machine (KELM), by which the flyrock distance (FRD) is predicted. Furthermore, the other three data-driven models including local weighted linear regression (LWLR), response surface methodology (RSM) and boosted regression tree (BRT) are also developed to validate the main model. A database gathered from three quarry sites in Malaysia is employed to construct the proposed models using 73 sets of spacing, burden, stemming length and powder factor data as inputs and FRD as target. Afterwards, the validity of the models is evaluated by comparing the corresponding values of some statistical metrics and validation tools. Finally, the results verify that the proposed KELM model on account of highest correlation coefficient (R) and lowest root mean square error (RMSE) is more computationally efficient, leading to better predictive capability compared to LWLR, RSM and BRT models for all data sets.
Red pelagic sediments are relatively common in the Phanerozoic. They are often interpreted as products of sea-bottom oxidation during greenhouse climate showing a conspicuous alternation with black ...shales and thus carrying important palaeoceanographic information. The Lower Devonian (Pragian) carbonate strata of the Prague Basin, Czech Republic (Praha Formation) contain a marked band of red pelagic carbonate, up to ~15m thick, which can be correlated for several tens of km. We investigated seven sections (17 to 255m thick) of the Prague Basin using the methods of facies analysis, outcrop gamma-ray logging, diffuse reflectance spectroscopy, optical microscopy, element geochemistry, magneto-mineralogy and electron microprobe analysis. The aim was to find the mineral carriers of the red colour, investigate the stratigraphic context of the red carbonates and evaluate the local and global prerequisites for their formation. The red pigmentation represents enrichment by hematite with respect to goethite. Approximately 31% of the total reflectance falling in the red colour band represents a threshold for red coloration. The red pigmentation is carried by submicronic hematite dispersed in argillaceous pelagic calcilutite and/or inside skeletal allochems. Gamma-ray log correlation indicates that the red carbonate band developed in stratigraphic levels with low sedimentation rates, typically from 1 to 7.1mm/kyr, which are comparable to the Mesozoic Rosso Ammonitico facies. The red beds and the whole Praha Formation (Pragian to early Emsian) are characterized by low TOC values (<0.05%) and low U/Th, Mo/Al, V/Al, Zn/Al, Cu/Al and P/Al ratios indicating oligotrophic, highly oxic sea-bottom conditions. This period was characterized by global cooling, a drop in silicate weathering rates and in atmospheric pCO2 levels. The lower Devonian successions of the Prague Basin indicate that switching between two greenhouse climatic modes, colder oligotropic and warmer mesotrophic, may have been responsible for the alternation of red and grey carbonate strata, respectively.
•Lower Devonian oceanic red beds (ORB) were formed in oligotrophic, oxic bottom conditions.•Sea bottom conditions during Pragian reflected global cooling.•Low sediment accumulation rates are prerequisite for hematite enrichment in ORB.•A threshold of red coloration can be quantified from red band reflectance.•Grey carbonates and ORB switching reflects changes in trophic levels and bottom oxygenation.
Rock fragmentation due to blasting depends upon many parameters. The properties of the explosive are one of them. In limestone quarries, ammonium nitrate–fuel oil (ANFO) or site mixed emulsion (SME) ...are generally used for rock fragmentation. Both these explosives cause substantial changes in the breakage mechanism of rockmass thereby affecting the fragmentation. This paper reports the effect of type of the explosive and blast hole diameter on the boulder count in limestone quarry blasting. In all, 264 blasts using ANFO or SME explosives have been conducted in nearby limestone quarries. The blasts have been conducted for 152 mm diameter and 115/100 mm blast holes. The analysis of the results indicates that the SME explosives are more suitable explosive in limestone quarries than ANFO for reducing the boulder count. SME has caused a reduction in generation of boulders for both 152 and 100 mm diameter blast holes when compared to ANFO. Moreover, the blasts with larger diameter blast holes charged with SME have resulted in less boulders than smaller diameter blast holes charged with the same explosive.
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