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Open Access Article
1 - Belemnite biostratigraphy of the upper Jurassic to lower Cretaceous strata in the Surghar range, NW Pakistan: Systematic and Paleobiogeographic implications
Sajjad Ahmad Zia Rehman Suleman Khan Bilal Wadood Mati Haq Shuhab Khan Yasir Khan Hasnain Khan Shehla GulFour belemnite genera and twelve age-diagnostic species were identified from the from Upper Jurassic–Lower Cretaceous sequence of the Chichali Formation, northwest Pakistan. Four local biozones were established based on the identified belemnites. These biozones ar MoreFour belemnite genera and twelve age-diagnostic species were identified from the from Upper Jurassic–Lower Cretaceous sequence of the Chichali Formation, northwest Pakistan. Four local biozones were established based on the identified belemnites. These biozones are arranged from base to top as follows; Hibolithes pilleti/Hibolithes jaculoides/Hibolithes hastatus Zone of Kimmeridgian age, Hibolithes marwicki marwicki/Hibolithes arkelli Zone of Tithonian age, Belemnopsis malucana Zone defines Tithonian–Berriasian boundary, and Neohibolites ewaldi/Hibolithes longior/Belemnopsis jonkeri Zone of Velanginian age. The biostratigraphic and paleogeographic occurrences of belemnites in the Tethyan and Boreal Realms were used to identify the migration pathways and distinctive paleobiogeographic provinces of belemnites. The paleoceanic settings closely linked the Upper Jurassic strata (~Biozones 1–2, representing the Kimmeridgian–Tithonian range) in the Tethyan and the Boreal Realms. The Lower Cretaceous (~Biozone 3, representing the Berriasian) strata also reveal a persistent oceanic connection between the Indo-Pacific and Mediterranean Provinces. However, the Boreal and Tethyan Realms were also connected in the Lower Cretaceous (~Biozone 4, representing the Velanginian strata) by shallow-water routes. Manuscript profile -
Open Access Article
2 - Influence of rock properties on emission rate of Particulates Matter (Pm) during drilling operation in surface mines
Koneti Nagesha Harinandan Kumar Muralidhar MunisinghThe mining process generates significant amount of dust in the form of particulate matters into the atmosphere. Out of different mining process, opencast mining produces more dust than that of underground mining because of exposure in the ambiance. The mining operations MoreThe mining process generates significant amount of dust in the form of particulate matters into the atmosphere. Out of different mining process, opencast mining produces more dust than that of underground mining because of exposure in the ambiance. The mining operations are directly or indirectly involved in the production of dust particles. The activities like drilling operation, Blasting and haul road operations produce fugitive dust and causes significant deterioration of mine atmosphere. This fugitive dust consists of particulate matters (PM), which are more harmful to the human respiratory system. The prevention measures is only possible when the actual prediction of emission of those fugitive dust particles are possible. There is several model that predict the emission of the dust particles, but there is very less model to predict fugitive dust produced from a drilling operation in surface mines. In this paper, study was carried out to develop dust prediction model and to assess the influence of rock properties on dust emission. Based on the results obtained the developed model exhibit close proximity of predicted as well as field measured values with a regression coefficient of 0.75. Thus, the development of the model with effective prediction capability is the novelty of this paper. Decrease in dust emission rate was observed with increased moisture content present in drill cuttings, higher compressive strength, and density. Manuscript profile -
Open Access Article
3 - SPS Model: a significant algorithm to reduce the time and computer memory required in geostatistical simulations
Behnam SadeghiIn geochemical anomaly classification, different mathematical-statistical models have been applied. The final classified map provides only one scenario. This model is not certain enough since every model provides several thresholds which are almost different from each o MoreIn geochemical anomaly classification, different mathematical-statistical models have been applied. The final classified map provides only one scenario. This model is not certain enough since every model provides several thresholds which are almost different from each other meaning dissimilarity and spatial uncertainty of the classified maps. Spatial uncertainty of the models could be quantified considering the difference between the associated geochemical scenarios simulated (called: ‘realizations’) by geostatistical simulation (GS) methods. However, the main problem with GS methods is that these methods are significantly time-consuming, and CPU- and memory-demanding. To improve such problems, in this research, the method of “scaling and projecting sample-locations (SPS)” is developed. Based on the SPS theory, first of all, the whole sample-locations were projected (centralized) and scaled into a box coordinated between (0,0) to (150,0) and (0,0) to (0,100), for example (they can be equal though), with the cell-size of 1 m2. Therefore, the time consumed and the memory demanded to generate a large number of realizations, for example, 1000 realizations based on the non-scaled/non-projected (NS/NP) and scaled/projected (S/P) sample locations per case-study were quantified. In this study, the turning bands simulation (TBSIM) were applied to geochemical datasets of three different case studies to take the area scales, regularity/irregularity and density of the samples into account. The comparison between NS/NP and S/P results statistically demonstrated the same results, however, the process and outputs of the S/P samples took a significantly shorter time and consumed a remarkably lower computer-memory. Therefore, experts are able to easily run this algorithm using any normal computer. Manuscript profile -
Open Access Article
4 - Prognosis of of gold mineralization phases by multifractal modeling in the Zehabad epithermal deposit, NW Iran
سمیه شهبازی مجید قادری Peyman AfzalConcentration–Number (C–N) fractal method has been used for determining and separating mineralization phases based on surface lithogeochemical Au, Ag, Cu, Pb, Zn, As and Sb data in the Zehabad epithermal deposit, NW Iran. Five mineralization phases are demon MoreConcentration–Number (C–N) fractal method has been used for determining and separating mineralization phases based on surface lithogeochemical Au, Ag, Cu, Pb, Zn, As and Sb data in the Zehabad epithermal deposit, NW Iran. Five mineralization phases are demonstrated by multifractal modeling for the mentioned elements correlating with geological studies. The extreme phase of Au mineralization is higher than 7.9 ppm, which is correlated with hematite deposition in silicic veins and veinlets, whereas Ag (˃79.43 ppm), Cu (˃15.85%), Pb (˃63.1%), Zn (˃11.2%) extreme phases are associated with the main stage sulfidation phases. The results show that Au, Cu, Pb, Zn and Ag have two different mineralization trends based on the multifractal nature in this area. These trends are presented based on oxidic and sulfidic mineralization. According to mineralogical studies, the main stages of mineralization include: 1) formation of chalcopyrite ± sphalerite in silicic veins in sulfidic trend; 2) deposition of native gold and specular hematite in silicic veins in response to boilling, in oxidic trend; 3) next phase of fluid penetration and replacing chalcopyrite by galena, sphalerite and tetrahedrite-tennantite in the sulfide veins, in sulfic trend. Neighbouring copper and silver are due to the formation of tetrahedrite-tennantite solid solution. The obtained results show a positive correlation between mineralization phases and the faults present at the deposit. Moreover, mineralization phases of these elements demonstrate a good correlation with silicification and silicic veins and veinlets. Manuscript profile -
Open Access Article
5 - Evaluation of the geometallurgical indices for comminution properties at Sarcheshmeh porphyry copper mine, Iran
Saiwan Mohammadi Bahram Rezai AliAkbar Abdollazadeh Sayed Mojtaba MortazaviGeometallurgy has become an important tool to predict the processing behaviour of ores, and to decrease the production risks associated with the variable nature of economic mineral deposits. Understanding the ore variability and subsequently the response of the ore to p MoreGeometallurgy has become an important tool to predict the processing behaviour of ores, and to decrease the production risks associated with the variable nature of economic mineral deposits. Understanding the ore variability and subsequently the response of the ore to processing are considered to be the most important functions of an accurate geometallurgical study. In this paper geometallurgical indices for grinding properties of a copper ore are investigated. Geometallurgical index (GI) is described as any geological feature which makes a footprint on the processing performance of the ores. A comprehensive study at Sarcheshmeh porphyry copper mine was undertaken. This included the process responses of the ore such as grade, recovery and plant throughput as possible geometallurgical indices. In this paper the effects of rock breakage variability on the plant throughput and energy consumption are presented. Ninety samples were collected based on geological features including lithology, hydrothermal alteration, and geological structures. The samples were characterized using X-ray diffraction, X-ray fluorescence, electron and optical microscopy. A small scale simulated test method for Bond ball mill work index (BWI) was used to perform the comminution examinations. The results showed that BWI values vary from 5.67 kWh/t to 20.21 kWh/t. Examination of the possible correlations between BWI and the geological features showed that the key geological feature related to comminution variability is lithology. In addition, the hydrothermal alteration would be an effective parameter in the period that the plant is fed with a single lithology. Manuscript profile -
Open Access Article
6 - Rapid moment magnitude estimation for large earthquakes in Iran using time integration of absolute ground accelerations
Hossein Sadeghi Behnam Rahimi Parvin BabaeiA total of 324 strong ground-motion records from 26 earthquakes with moment magnitude greater than 6 were used to derive an adequate equation for moment magnitude estimation. A parameter called total effective shaking was used to introduce an empirical equation for dete MoreA total of 324 strong ground-motion records from 26 earthquakes with moment magnitude greater than 6 were used to derive an adequate equation for moment magnitude estimation. A parameter called total effective shaking was used to introduce an empirical equation for determining the near real-time magnitude of the Iranian plateau. This parameter was obtained through time integration of the absolute acceleration values from accelerograms over the strong shaking duration. It can be calculated by a simple mathematical procedure 5 seconds after completion of the waveform by decreasing the amplitudes to less than 20% of the maximum ground acceleration. The total effective shaking has a dimension of velocity and corresponds to moment magnitude and hypocentral distance in an attenuation relationship. The optimum coefficients were calculated through least-square regression analysis. Also, the effect of site conditions was evaluated in the analysis. The average shear-wave velocity to a depth of 30 m beneath each recording station was taken into account as the local site effect for 147 records out of the total number of records. The estimated moment magnitudes are in reasonably good agreement with the Global CMT values. Their differences are mostly less than 0.25 in the magnitude unit. Manuscript profile
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