Numerical fault simulation in Himalayas with 2 D finite element method

The nature of the stress field in the Himalaya is examined by the 2D finite element method where linear elastic rheology and plain strain condition are assumed. The Mohr-Coulomb failure criterion has been adopted to analyze the relationship between stress distribution and fault formation.Two profile models are prepared and convergent displacement is imposed on them along the NE-SW horizontal direction.The convergent displacement and physical properties of the rock layer control the distribution,orientation,magnitude and intensity of the stress and fault development.According to the calculated stress pattern,thrust faults are expected to develop in the central Himalaya (model A).Normal and some thrust faults take place in the north-western Himalaya (model B).The results from our numerical experiment are in agreement with those from the seismicity and focal mechanism solution of earthquakes and also with those of M.M.Alam and D.Hayashi (Bull.Fac.Sci.Univ. Ryukyus, 73, 15, 2002) in the central Himalaya

Assessment of soil quality for agricultural purposes around the Barapukuria coal mining industrial area, Bangladesh: insights from chemical and multivariate statistical analysis

Abstract Background Barapukuria coal mine which has been operating from 2002 is situated in such a location that is dependent on agriculture. Pollution from Coal mining poses a huge risk to the ecosystem and surrounding soil. So, there could be some impact of the Barapukuria coal mine on the surrounding soil. The main aim of this study is to identify the soil quality of the study area and also see how much the soil is deviated from its standard reference value. Results From the result it has been identified that pH of the soil is relatively low near the coal mine due to the acid mine drainage. Moreover, Total Nitrogen of the soil samples is also below than the standard value. On the other hand, Iron (Fe), Potassium (K), and Organic matter (OM) and Copper (Cu) are relatively higher than the Standard Reference value for agriculture. So, it is clear that Iron pyrite (FeS2) and chalcopyrite (CuFeS2) which are released during mining operations is the pivotal reason for the degradation of the soil of the surrounding area. Various statistical analytical tools have been used in this study for analyzing the data. Correlation matrix and factor analysis show that degradation of soil is encountered because of anthropogenic causes i.e. because of the coal mine. Besides, cluster analysis entails that which soil samples are deviated from their standard condition and also classifies the soil samples according to their homogeneity. Moreover, one way ANOVA identifies the soil quality controlling factors and the spatial variability of soil samples. Conclusion From the agricultural point of view, this study reveals that there are significant factors involved in the degradation of the soil and this degradation is occurring rapidly. The nutrients in the soil for plant growth such as Nitrogen (N), Potassium (K), Iron (Fe), Copper (Cu) and Organic matter (OM) are deviated from the standard reference value due to mining activities which ultimately affect the annual paddy production of the study area

有限要素法によるヒマラヤの主要スラストのシミュレーション

The Himalayan mountain system developed from the powerful earth movements which occurred as the Indian plate pressed against the Eurasian continental plate. A series of elastic finite element models are presented to examine the development of major thrusts (MCT, MBT and MFT) in the central Himalaya. Balanced geologic profiles of the central Himalaya which are modified from Johnson's profiles (2002) are used for the purpose under plane strain condition. The convergent rate of India has changed 10 cm/a at 40 Ma, 5 cm/a at 20 Ma and 2 cm/a at 10 Ma. Results show that the horizontal compressive stress σ_1 leads to the development of thrust faults in the Ththys Himalaya, Higher Himalaya, Lesser Himalaya, Sub-Himalaya and incipient zones of MCT, MBT and MFT. Especially, the thrust faults are highly concentrated within the whole area of the incipient zones, which influenced the formation of MCT, MBT and MFT at their early stage.大規模な地殻の運動によって出現したヒマラヤ山系はインドプレートとユーラシア大陸プレートとの衝突によりもたらされた．ここに取り上げた一連の弾性有限要素モデルは中央ヒマラヤの主要スラスト（MCT，MBT，MFT）の発達過程を表している．Johnson（2002）によって作成された中央ヒマラヤのバランス地質断面図を多少修正したものを平面ひずみの条件のもとで使用した．インドプレートの速度を40Maでは10cm／年，20Maでは5cm／年，10Maでは2cm／年に設定した．シミュレーションの結果，水平圧縮応力σ_1はテーチスヒマラヤ，高ヒマラヤ，低ヒマラヤ，サブヒマラヤ，そしてMCT，MBT，MFTの萌芽地帯にスラストを生じさせた．特に将来MCT，MBT，MFTとなる萌芽地帯全体でのスラストの発生する領域の占める割合は高い

An application of Water Quality Index (WQI) and multivariate statistics to evaluate the water quality around Maddhapara Granite Mining Industrial Area, Dinajpur, Bangladesh

Abstract Background Pure water is an absolutely necessary component of the earth not only for life but also for sustainable socio-economic development of today’s civilization. The aim of this study was to analysis the quality of water resources and to investigate the influences of mining activities on water quality around the Maddhapara Granite Mining area, Dinajpur, Bangladesh. Result 31 samples from surface and groundwater were collected from this selected area to assess their hydrochemistry, suitability, and their possible sources of contamination. Consequently, in the case of physico-chemical analysis, the 24 parameters such as PH, Electrical Conductivity, TDS, TH, Ca2+, Mg2+, K+, Cd2+, Cr3+, Cl−, $${\text{SO}}_{4}^{{2{ - }}}$$ SO 4 2 - , $${\text{PO}}_{4}^{3 - }$$ PO 4 3 - , $${\text{NH}}_{4}^{ + }$$ NH 4 + , $${\text{NO}}_{3}^{{ - }}$$ NO 3 - , $${\text{HCO}}_{3}^{{ - }}$$ HCO 3 - etc. were analyzed in laboratory. Multivariate statistical methods were adopted for determining the water quality and their sources of contamination. The Gibbs ratio plot suggests that most of the samples fall in the rock dominance fields and some are in the precipitation dominance field. Cluster analysis confirms that three main groups of water samples where cluster I includes 70.97% of water samples, cluster II and cluster III includes rest 22.58 and 6.45% of the water samples respectively. Factor Analysis/Principal Component Analysis (FA/PCA) illustrates five factors extracted which explain 75.89% of the total variance. Conclusion The collective results of multivariate analysis and Water Quality Index implies that most of the areas around the mining area are dominated by the good to excellent quality water for different purposes. In addition, the results of this research will then be helpful to estimate the major sources of contamination in different areas within the framework of activities intending to improve the quality of water

Hydraulic Fill Assessment Model Using Weathered Granitoids Based on Analytical Solutions to Mitigate Rock Mass Instability in Conventional Underground Mining

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.This study uses analytical solutions to assess a hydraulic fill model based on weathered granitoid to increase underground opening stability and mitigate rock bursts during mining operations in a conventional underground mining company located in the Coastal Batholiths of the Peruvian Andes. This study assesses the previous geological database provided by the mine, analyzes the on-site strengths produced by the exploitation works that will subsequently be filled, identifies the quality of the material used in the landfill (granitoids) through laboratory tests, and compares compressive strength at different depths, all contemplated within the landfill model used. This study focuses on the applicability of hydraulic fills in conventional underground mine using natural geological material such as granitoid.Revisión por pare