Recognition and consideration of “bonanzas” in calculation of ore deposit reserves

The “too-high” (bonanza) assays of gold ores, e.g., may be identified and the errors caused by them in estimations of gold content of ore blocks may be minimized by means of flexible cut-off (fig. 3) and appropriate substitutions, depending on grade of ore, number of assays available for the estimations, and other variables. – IGR Staff.     

Estimation of Earthquake Damage to Buried Pipelines Caused by Ground Shaking

One of the most critical lessons of the recent earthquakes is the need for seismic planning for lifelines, with appropriate supplies and back up systems for emergency repair and restoration. Seismic planning, however requires physical loss estimations before the earthquakes occur. Buried pipeline damage correlations are critical part of loss estimation procedures applied to lifelines for future earthquakes. We review the existing pipeline damage relationships only for ground shaking (transient ground deformations) in the light of recent developments and evaluate them with Denizli City, Turkey water supply system. Eight scenario earthquakes with four different earthquake magnitudes between M6 and M7 caused by two different fault ruptures (Pamukkale and Karakova-Akhan Faults) were used. Analyses were performed by using Geographical Information Systems (GIS). This high number of different scenario earthquakes made it possible to compare the pipeline damage relationships at different ground shaking levels. Pipeline damage estimations for Denizli City were calculated for each damage relationship and earthquake scenario. Relative effects of damage relationships and scenario earthquakes on the results were compared and discussed. The results were presented separately for brittle, ductile, and all pipelines. It was shown that the variation in ductile pipeline damage estimations by various relationships was higher than the variation in brittle pipeline damage estimations for a particular scenario earthquake.     

地下水位在非饱和水流数据同化中的应用

为理解地下水位观测信息在非饱和水流数据同化中的数据价值,建立了基于地下水位动态观测信息的一维饱和-非饱和水流集合卡尔曼滤波,通过虚拟数值实验检验了地下水位观测信息在非饱和水力参数估计和水分校正中的潜在价值。研究结果表明:在以地下水位为唯一观测数据时,同时更新参数和水头比仅更新水头能更好地校正土壤剖面的水头分布;当多层单个水力参数未知时,地下水位观测可以为参数估计提供有效信息;当多层多个参数未知时,地下水位与多层多个参数之间的复杂关系导致观测信息难以估计出最优的(唯一的)参数值;地下水位可作为辅助信息,与含水量观测等信息联合运用改善参数估计和含水量预测精度。     

Estimation of effective hydrogeological parameters by considering varying heterogeneity and pumping rates

Darcy’s law and pumping tests, Tabu searches (TS) integrated with the Adjoint State Method (ASM), are two upscaling approaches used to transform local hydrogeological parameters at the scale of measurement into effective parameters on larger scales. This study proposed the above methods in order to estimate the effective parameters of heterogeneous and anisotropic aquifers at different degrees of heterogeneity (variances and correlation lengths). The results revealed three important principles: (1) the means of the effective transmissivities by Darcy’s law under different Dirichlet boundary conditions are used as the real ones in this study, because the optimal values under different Dirichlet boundary conditions are very close to each other at the same level of heterogeneity; (2) the estimations by TS integrated with ASM at low degrees of heterogeneity are much closer to the means of optimums by Darcy’s law than the estimations at high degrees of heterogeneity. Regardless of the pumping rate, the optimum at high degrees of heterogeneity is not good enough to represent the total study field. In considering the estimations at low degrees of heterogeneity, the drawdown caused by a low pumping rate is not sufficient to identify the effective parameters, while the drawdown caused by a higher pumping rate is useful for estimating the effective parameters. This suggests that the range of pumping rates influences the results estimated by TS and ASM, and the effective parameters identified using the effective range of pumping drawdown are more than enough to represent the whole study aquifer. With a larger variance of heterogeneity, the range of the pumping rate becomes smaller, leading to results closest to those estimated by Darcy’s law; (3) the estimations are influenced by the variances of heterogeneity more than the correlation lengths of heterogeneity.     

A GIS-based tool for flood damage assessment and delineation of a methodology for future risk assessment: case study for Annotto Bay,Jamaica

Natural Hazards - Flood risk assessments and damage estimations form integral parts of the disaster risk management in Jamaica, owing its vulnerability to hydrometeorological hazards. Although...     

An imitation stochastic model for lateral hydrocarbon migration

Application of stochastic simulation to study of lateral migration of primary hydrocarbon pools near the roof of a collector is considered. It is shown that this approach can be used for point and interval estimations of oil accumulation in a trap and the formation of residual oil saturation.     

Multidimensional spectrum estimation for nonstationary processes

A spectrum estimation method for multidimensional nonstationary processes has been developed. The estimation method has been applied to a nonstationary two-dimensional random field. The numerical findings show that the results of the estimations are about what can be expected from a multidimensional estimation for a nonstationary process.     

Applying the HAZUS-MH software tool to assess seismic risk in downtown Ottawa,Canada

The aim of this paper is to present earthquake loss estimations for a portion of downtown Ottawa, Canada, using the HAZUS-MH (Hazards United States Multi-Hazard) software tool. The assessment is performed for a scenario earthquake of moment magnitude 6.5, at an epicentral distance of 15 km, occurring during business hours. A level 2 HAZUS-MH analysis was performed where the building inventory, microzonation studies, and site-specific ground motion hazard maps (2% exceedence probability in 50 years) were all improved based on local information. All collected data were assembled into a set of standard geodatabases that are compatible with the HAZUS-MH software using a GIS-specific procedure. The results indicate that the greatest losses are expected in unreinforced masonry buildings and commercial buildings. Sensitivity studies show that soil classes, the vulnerability of schools, and the spatial scale of loss estimations are also important factors to take into account.     

Formation dynamics of filled veins during drainage

The mathematical model here developed proves to be suited for estimations of parameters of the mass-exchange (table 1), deposition of salts in a growing fissure, and others, in situations where filling of a fissure is complicated by drainage of fluid from pores in the rock into that fissure.     

Calculating depth of deposition and volume of gas expelled during eruptions of mud volcanoes in southern Sakhalin

The geological structure of mud volcanoes in southern Sakhalin is stated briefly. Character of eruptions and opinions on the mechanism of the origin of eruptions are described, as well as approximate estimations of depths of occurrence of the gas deposit and the volume of exploding gas. – Authors.     

Structure and parameter schematization of the vadose zone for groundwater recharge modeling

On the basis of published soil profile data typical retention curves and hydraulic conductivity functions were obtained that depend on soil depth, lithological characters, and different surface landscape conditions. The corresponding average soil hydraulic parameters for M.Th.Van Genuchten equations were estimated. These average soil parameters are suitable for groundwater recharge estimations based on unsaturated flow modeling.     

滑坡位移的多模态支持向量机模型预测

将支持向量机（support vector machine,SVM）方法与信号分析中的经验模态分解（empirical mode decomposition, EMD）方法相匹配,提出了一种通过多模态支持向量机函数回归分析建模预测滑坡位移的理论方法。以边坡位移历史观测数据为基础,应用EMD方法获得滑坡形成过程中位移演化的几个特征时间模态,构成了多模态信息统计学习样本,确定了边坡位移演化的自适应多尺度变化信息。对应于每个经验模态的位移变化信息,引入了多模态SVM建模方法,然后合成不同经验模态下边坡位移的计算结果,得到滑坡位移的预测值。以卧龙寺新滑坡和新滩滑坡的监测数据为基础的理论预测结果表明,与采用遗传算法的神经网络方法的预测结果相比,支持向量机经验模态方法具有更强的预测能力,理论预测结果与实际监测值具有很好的一致性     

A GENERAL ESTIMATE OF THE WORLD'S COAL RESOURCES

A comparative estimation of coal reserves for the foreign countries and the USSR is given. It emphasizes the existence of considerable variations in quantitative coal reserve estimations of the foreign countries in consequence of the absence of a unitary method of coal resource estimation. It is necessary therefore to estimate world coal reserves in accordance with the unitary method as it was done in 1913 and 1956 (USSR). — auth. English summ.     

非饱和流节点间导水率估计及达西平均分析

针对由Gardner-Russo函数描述的特征土壤,在双饱和度坐标系中,探讨了常规节点间导水率估计与量纲一水平达西平均(k*_H)和量纲一垂直达西平均(k*_V)的差异.k*_H是相邻两节点饱和度的函数,而k*_V也是空间步长(Δx)和特征参数(α)的函数.对水平非饱和流,算术平均高估导水率,而几何与调和平均低估导水率;从相对误差空间分布看,几何平均优于算术和调和平均.对垂直非饱和流,随Δx(或α)的增大,常规估计的相对误差空间顺(或逆)时针旋转并缩小,从而降低模型准确性.k*_H等值线具有对称性,而k*_V不具对称性;仅当Δx或α足够小时,k*_H才趋近于k*_V.因此,为提高非饱和流数值模拟的准确性,必须采用精确的达西平均来计算节点间导水率.     

Modeling of damage-related earthquake losses in a moderate seismic-prone country and cost–benefit evaluation of retrofit investments: application to France

We performed large-scale earthquake economic loss estimations for France and cost–benefit analyses for several French cities by developing a semiempirical, intensity-based approach. The proposed methodology is inexpensive and easily applicable in case of a paucity of detailed information regarding the specific regional seismic hazard and the structural characteristics of the building stock, which is of particular importance in moderate-to-low seismic hazard regions. The exposure model is derived from census datasets, and the seismic vulnerability distribution of buildings is calculated using data mining techniques. Several hypothetical, large-scale retrofit scenarios are proposed, with increasing levels of investment. These cities, in their respective reinforced states, are then subjected to a series of hazard scenarios. Seismic hazard data for different return periods are calculated from regulatory accelerations from French seismic zoning. Loss estimations for the original (non-reinforced) configuration show high levels of expected building repair and replacement costs for all time spans. Finally, the benefits in terms of damage avoidance are compared with the costs of each retrofit measure. Relatively limited strengthening investments reduce the probability of building collapse, which is the main cause of human casualties. However, the results of this study suggest that retrofitting is, on average, only cost-effective in the parts of France with the highest seismicity and over the longest time horizons.     

Regional characterisation of hydraulic properties of rock using air-lift data

 Hydrogeologic studies are commonly data-intense. In particular, estimations of hydraulic properties of hard rock often require large amounts of data. In many countries, large quantities of hydrogeologic data have been collected and archived over the years. Therefore, the use of existing data may provide a cost-efficient alternative to collecting new data in early stages of hydrogeologic studies, although the available data may be considered imprecise. Initially, however, the potential usefulness, i.e., the expected accuracy, of the available data in each specific case must be carefully examined. This study investigates the possibilities of obtaining estimates of transmissivity from hard-rock air-lift data in Sweden within an order of magnitude of results obtained from high-quality injection-test data. The expected accuracy of the results was examined analytically and by means of statistical methods. The results were also evaluated by comparison with injection-test data. The results indicate that air-lift data produce estimates of transmissivity within an order of magnitude compared to injection-test data in the studied examples. The study also shows that partial penetration and hydrofracturing may only affect the estimations approximately half an order of magnitude. Thus, existing data may provide a cost-efficient alternative to collection of new data in early stages of hydrogeologic studies. Received, January 1998 Revised, November 1998, December 1998 Accepted, December 1998     

Groundwater recharge in irrigated semi-arid areas: quantitative hydrological modelling and sensitivity analysis

For semi-arid regions, methods of assessing aquifer recharge usually consider the potential evapotranspiration. Actual evapotranspiration rates can be below potential rates for long periods of time, even in irrigated systems. Accurate estimations of aquifer recharge in semi-arid areas under irrigated agriculture are essential for sustainable water-resources management. A method to estimate aquifer recharge from irrigated farmland has been tested. The water-balance-modelling approach was based on VisualBALAN v. 2.0, a computer code that simulates water balance in the soil, vadose zone and aquifer. The study was carried out in the Campo de Cartagena (SE Spain) in the period 1999–2008 for three different groups of crops: annual row crops (lettuce and melon), perennial vegetables (artichoke) and fruit trees (citrus). Computed mean-annual-recharge values (from irrigation+precipitation) during the study period were 397 mm for annual row crops, 201 mm for perennial vegetables and 194 mm for fruit trees: 31.4, 20.7 and 20.5% of the total applied water, respectively. The effects of rainfall events on the final recharge were clearly observed, due to the continuously high water content in soil which facilitated the infiltration process. A sensitivity analysis to assess the reliability and uncertainty of recharge estimations was carried out.     

Decompression mineral microtextures in granulites of the Irkut block (Sharyzhalgai uplift of the Siberian Platform)

This paper presents mineral reactions in metapelites and estimations of PT-conditions of metamorphism for paragranulites of the Irkut block of the Sharyzhalgay uplift (Siberian Platform). The geothermometeric data based on exchange reactions, the contents of Na in cordierite and Ti in zircon indicate that the peak temperature of metamorphism reached ca. 800 °C at 6–7 kbar. The observed mineral reactions suggest that the pressure decreased to ca. 3 kbar at a retrograde stage of metamorphism.     

Calibration and spatial modelling of daily ET<Subscript>0</Subscript> in semiarid areas using Hargreaves equation

Evapotranspiration is difficult to measure and, when measured, its spatial variability is not usually taken into account. The recommended method to estimate evapotranspiration, Penman-Monteith FAO, requires variables not available in most weather stations. Simplified but less accurate methods, as Hargreaves equation, are normally used. Several approaches have been proposed to improve Hargreaves equation accuracy. In this work, 14 calibrations of the Hargreaves equation are compared. Three goodness of fit statistics were used to select the optimal, in terms of simplicity and accuracy. The best option was an annual linear regression. Its parameters were interpolated using regression-kriging combining Random Forest and Ordinary Kriging. Twelve easy to obtain ancillary variables were used as predictors. The same approach was used to interpolate Hargreaves and Penman-Monteith-FAO ET₀ on a daily basis; the Hargreaves ET₀ layers and the parameter layers were used to obtain calibrated ET₀ estimations. To compare the spatial patterns of the three estimations the daily layers were integrated into annual layers. The results of the proposed calibration are much more similar to Penman-Monteith FAO results than those obtained with Hargreaves equation. The research was conducted in south-east Spain with 79 weather stations with data from 01/01/2003 to 31/12/2014.     

Bias adjustment of satellite-based precipitation estimation using artificial neural networks-cloud classification system over Saudi Arabia

Precipitation is a key input variable for hydrological and climate studies. Rain gauges can provide reliable precipitation measurements at a point of observations. However, the uncertainty of rain measurements increases when a rain gauge network is sparse. Satellite-based precipitation estimations SPEs appear to be an alternative source of measurements for regions with limited rain gauges. However, the systematic bias from satellite precipitation estimation should be estimated and adjusted. In this study, a method of removing the bias from the precipitation estimation from remotely sensed information using artificial neural networks-cloud classification system (PERSIANN-CCS) over a region where the rain gauge is sparse is investigated. The method consists of monthly empirical quantile mapping of gauge and satellite measurements over several climate zones as well as inverse-weighted distance for the interpolation of gauge measurements. Seven years (2010–2016) of daily precipitation estimation from PERSIANN-CCS was used to test and adjust the bias of estimation over Saudi Arabia. The first 6 years (2010–2015) are used for calibration, while 1 year (2016) is used for validation. The results show that the mean yearly bias is reduced by 90%, and the yearly root mean square error is reduced by 68% during the validation year. The experimental results confirm that the proposed method can effectively adjust the bias of satellite-based precipitation estimations.