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1.
Mineral-potential mapping is the process of combining a set of input maps, each representing a distinct geo-scientific variable, to produce a single map which ranks areas according to their potential to host mineral deposits of a particular type. The maps are combined using a mapping function that must be either provided by an expert (knowledge-driven approach), or induced from sample data (data-driven approach). Current data-driven approaches using multilayer perceptrons (MLPs) to represent the mapping function have several inherent problems: they are highly sensitive to the selection of training data; they do not utilize the contextual information provided by nondeposit data; and there is no objective interpretation of the values output by the MLP. This paper presents a new approach by which MLPs can be trained to output values that can be interpreted strictly as representing posterior probabilities. Other advantages of the approach are that it utilizes all data in the construction of the model, and thus eliminates any dependence on a particular selection of training data. The technique is applied to mapping gold mineralization potential in the Castlemaine region of Victoria, Australia, and results are compared with a method based on estimating probability density functions. 相似文献
2.
Conventional evaluation of quantitative mineral potential has focused on target selection at small scales. Mapping at small scales usually results in large-area targets, which may be suitable for grass-roots exploration or regional evaluation of potential. Unfortunately, the estimates in small-scale exploration are commonly associated with large uncertainties. Large-scale estimation is used for optimal in-fill drilling design and step-out drilling target selection. In-fill drilling helps to confirm ore-grade continuities and translate a portion of geological resources into minable reserves, whereas step-out target estimation is useful for finding new orebodies in the vicinity of known ore deposits. Both of these processes are necessary for mine development and production planning. A comprehensive methodology is proposed here, particularly for large-scale mineral exploration. The central information synthesizer is canonical or indicator favorability analysis. A case study is presented to demonstrate the methodology for large-scale target selection. The study involves a gold-mining district where step-out drilling targets are being sought to expand the resource base. Several drilling targets were delineated in the study region. Two of them were tested through surface sampling with positive results. 相似文献
3.
The representation of geoscience information for data integration 总被引：17，自引：0，他引：17
In mineral exploration, resource assessment, or natural hazard assessment, many layers of geoscience maps such as lithology, structure, geophysics, geochemistry, hydrology, slope stability, mineral deposits, and preprocessed remotely sensed data can be used as evidence to delineate potential areas for further investigation. Today's PC-based data base management systems, statistical packages, spreadsheets, image processing systems, and geographical information systems provide almost unlimited capabilities of manipulating data. Generally such manipulations make a strategic separation of spatial and nonspatial attributes, which are conveniently linked in relational data bases. The first step in integration procedures usually consists of studying the individual charateristics of map features and interrelationships, and then representing them in numerical form (statistics) for finding the areas of high potential (or impact).Data representation is a transformation of our experience of the real world into a computational domain. As such, it must comply with models and rules to provide us with useful information. Quantitative representation of spatially distributed map patterns or phenomena plays a pivotal role in integration because it also determines the types of combination rules applied to them.Three representation methods—probability measures, Dempster-Shafer belief functions, and membership functions in fuzzy sets—and their corresponding estimation procedures are presented here with analyses of the implications and of the assumptions that are required in each approach to thematic mapping. Difficulties associated with the construction of probability measures, belief functions, and membership functions are also discussed; alternative procedures to overcome these difficulties are proposed. These proposed techniques are illustrated by using a simple, artificially constructed data set. 相似文献
4.
A new method for short- and long-term forecasting of mineral commodities based upon historical data is developed. The method, referred to as the latest trend tracing (LTT) model, is constructed as a weighting and adaptive approach based on a general linear model. The LTT model considers the functions of data location and statistical behavior. The newest data receive the largest weights, whereas the older data are given smaller weights. The LTT model is performed by an iterative algorithm. The data set is successively partitioned into training and testing subsets. Each LTT model is estimated and tested for each partition. The updated estimates are then synthesized to produce the final estimates based upon the data locations and estimation variances. The LTT model is demonstrated on two real case studies, one on the projection of U.S. aluminum consumption and the other on the forecasting of U.S. copper consumption. 相似文献
5.
The method of making quantitative assessments of mineral resources sufficiently detailed for economic analysis is outlined in three steps. The steps are (1) determination of types of deposits that may be present in an area, (2) estimation of the numbers of deposits of the permissible deposit types, and (3) combination by Monte Carlo simulation of the estimated numbers of deposits with the historical grades and tonnages of these deposits to produce a probability distribution of the quantities of contained metal.Two examples of the estimation of the number of deposits (step 2) are given. The first example is for mercury deposits in southwestern Alaska and the second is for lode tin deposits in the Seward Peninsula.The flow of the Monte Carlo simulation program is presented with particular attention to the dependencies between grades and tonnages of deposits and between grades of different metals in the same deposit. 相似文献
6.
Application of Mineral Exploration Models and GIS to Generate Mineral Potential Maps as Input for Optimum Land-Use Planning in the Philippines 总被引：4，自引：0，他引：4
Carranza Emmanuel John M. Mangaoang Jerrysal C. Hale Martin 《Natural Resources Research》1999,8(2):165-173
The inherent problems of classifying or inventorying potential mineral resources (as opposed to known mineral resources) pose specific challenges. In this paper, the application of a conceptual mineral exploration model and GIS to generate mineral potential maps as input to land-use policy decision-making is illustrated. We implement the criteria provided by a conceptual exploration model for nickeliferous-laterites by using a GIS to classify the nickeliferous-laterite potential of an area in the northeastern part of the Philippines. The spatial data inputs to the GIS are geological map data, topographic map data, and stream sediment point data. Processing of these data yields derivative maps, which are used as indicators of nickeliferous-laterite potential. The indicator maps then are integrated to furnish a nickeliferous-laterite potential map. This map is compared with present land-use classification and policy in the area. The results indicate high potential for nickeliferous-laterite occurrence in the area, but the zones of potential are in places where mineral resources development is prohibited. The prohibition was imposed before the nickeliferous-laterite potential was assessed by this study. Mineral potential classification therefore is a critical input to land-use policy-making so that prospective land is not alienated from future mineral resource development. 相似文献
7.
Graeme P. McLaren 《Natural Resources Research》1992,1(1):85-96
British Columbia covers a vast segment of the Cordillera Mountain system that is richly endowed with a diversity of resources. British Columbia's historic patterns of resource development increasingly have been in conflict with demands for greater environmental protection. To avoid such conflicts, a recently legislated process that provides for detailed mineral resource assessments in candidate park areas has stimulated the creation of a mineral potential classification system for use in land-use planning and policy decisions.A mineral potential study of the Chilko Lake Planning Area provided three unique categories of field data on which to build the classification system. These categories are geological setting, geochemistry, and mineral occurrences. Data in each category were compiled independently to provide indicators of mineral potential. The field data were used to develop a widely understood classification of mineral potential. The classification is based on two factors: favorability and degree of confidence. 相似文献
8.
Quantitative Analysis of Mineral Resources for Strategic Planning: Implications for Australian Geological Surveys 总被引：5，自引：0，他引：5
A quantitative valuation study has been made of Australian state surveys with the specific goals of (1) establishing the 'worth' of current programs upgrading state government geoscientific information infrastructure, and (2) considering the results of the valuation in terms of strategic planning. The study has been done from the perspective of the community as a whole and has been undertaken in two phases reflecting the different objectives of Australian state surveys in terms of the exploration industry and government policy-making. This paper reports on the second part of this valuation process, measuring the impact of upgraded survey data on government mineral policy decision processes. The valuation methodology developed is a comparative approach used to determine net benefit foregone by not upgrading information infrastructure. The underlying premise for the geological survey study is that existing and upgraded data sets will have a different probability that a deposit will be detected. The approach used in the valuation of geoscientific data introduces a significant technical component with the requirement to model both favorability of mineral occurrence and probability of deposit occurrence for two different generations of government data. The estimation of mineral potential uses modern quantitative methods, including the U.S. Geological Survey three-part resource-assessment process and computer-based prospectivity modeling. To test the methodology mineral potential was assessed for porphyry copper type deposits in part of the Yarrol Province, central Queensland. Results of the Yarrol case study supports the strategy of the state surveys to facilitate effective exploration by improving accuracy and acquiring new data, as part of resource management. It was determined in the Yarrol Province case study that in going from existing to upgraded data sets the area that would be considered permissible for the occurrence of porphyry type deposits almost doubled. The implication of this result is that large tracts of potentially mineralized land would not be identified using existing data. Results of the prospectivity modeling showed a marked increase in the number of exploration targets and in target rankings using the upgraded data set. A significant reduction in discovery risk also is associated with the upgraded data set, a conclusion supported by the fact that known mines with surface exposure are not identified in prospectivity modeling using the existing data sets. These results highlight the absence in the existing data sets of information critical for the identification of prospective ground.Quantitative resource assessment and computer-based prospectivity modeling are seen as complementary processes that provide the support for the increasingly sophisticated needs of Australian survey clients. Significant additional gains to the current value of geoscientific data can be achieved through the in-house analysis and characterization of individual data sets, the integration and interpretation of data sets, and the incorporation of information on geological uncertainty. 相似文献
9.
GIS techniques have been used in the evaluation of favorability for base-metal mineralization in an area comprising the Cerro Azul and Apiaí quadrangles (SG.22-X-B-IV and V, scale 1:100.000), Ribeira Valley, São Paulo and Paraná States, Brazil. Methods have been employed for selection and weighting of prospective variables when applying GIS techniques to a digital database consisting of geological, geochemical and airborne geophysics, and mineral occurrence information. The exploration variable selection and analysis were based on two mineralization models: (1) Panelas type, vein-type carbonate hosted, and (2) Perau type, sedimentary-exhalative. The overlay was performed by weighted linear combination (WLC) and order weighted average (OWA) methods. Both methods proved suitable for the study area, yielding similar results. The ordered weighted averaging analysis provided the best results, with favorability maps showing a large number of classes occupying relatively minor areas. In comparison, the weighted linear combination analysis produced more coherent results but without details for minor areas. The prospective parameters obtained are considered suitable for both Perau and Panelas types. Both methods are inexpensive, and are suitable for selection of prospective areas during geological surveys in areas similar to the studied one. 相似文献
10.
Guocheng Pan 《Natural Resources Research》1993,2(4):292-311
Favorability methods produce a unique measure for mineral potential mapping and quantitative estimation of mineral resources. Indicator favorability theory is developed in this study to account for spatial (auto and cross) correlations of regionalized geological, geochemical, and geophysical fields based on the indicator concept. Target and explanatory indicators are introduced to describe, respectively, direct and indirect evidence of the mineralization of interest. Mineralization is represented by a combination () of a set of target indicators. Indicator favorability theory estimates a regionalized favorability function in two stages: (1) estimate a linear combination of target indicators by maximizing var() and (2) estimate favorability functionF by minimizing estimation variance var[F–]. The model is established on the basis of a conceptual model of target. The favorability estimates can be justified by correlation analysis and cross validation in control areas. The indicator favorability theory is demonstrated on a case study for gold-silver mineral potential mapping based on geophysical, structural, and geochemical fields. 相似文献
11.
12.
Radial Basis Function Network for Ore Grade Estimation 总被引：1，自引：0，他引：1
Biswajit Samanta 《Natural Resources Research》2010,19(2):91-102
This paper highlights the performance of a radial basis function (RBF) network for ore grade estimation in an offshore placer
gold deposit. Several pertinent issues including RBF model construction, data division for model training, calibration and
validation, and efficacy of the RBF network over the kriging and the multilayer perceptron models have been addressed in this
study. For the construction of the RBF model, an orthogonal least-square algorithm (OLS) was used. The efficacy of this algorithm
was testified against the random selection algorithm. It was found that OLS algorithm performed substantially better than
the random selection algorithm. The model was trained using training data set, calibrated using calibration data set, and
finally validated on the validation data set. However, for accurate performance measurement of the model, these three data
sets should have similar statistical properties. To achieve the statistical similarity properties, an approach utilizing data
segmentation and genetic algorithm was applied. A comparative evaluation of the RBF model against the kriging and the multilayer
perceptron was then performed. It was seen that the RBF model produced estimates with the R
2 (coefficient of determination) value of 0.39 as against of 0.19 for the kriging and of 0.18 for the multilayer perceptron. 相似文献
13.
基于WebMGIS的矿山安全实时监测集成系统及其应用 总被引：5，自引：0，他引：5
矿山安全实时监测对矿山安全与防灾减灾具有重要的意义。该文在分析当前国内矿山GIS(MGIS)、矿山安全监测系统(MSMS)研究与应用现状的基础上,指出MGIS与MSMS在企业网上进行集成的必要,提出了统一的时空框架下系统集成后的功能和总体结构,论述系统集成中的开发方法选择、时空数据组织、空间数据接口、数据库访问方法及页面更新等问题,最后对该系统在开滦林南仓的成功应用作了简要介绍。 相似文献
14.
The working group Mathematical Geology of the Freie Universität Berlin was formed in 1971. We review quantitative methods used by the working group since 1983 to treat mineral exploration problems. The methods applied vary from elementary statistical analysis of multivariate exploration data to optimal strategies for selecting favorable targets, and from multiobjective decision-making for additional drill hole locations to expert systems in exploration.The methods applied are directly related to the level of information at each stage of the exploration process. Special emphasis was placed on the relationship between and evaluation of subjective and objective data. Case studies illustrating the various methods are presented for different kinds of mineral deposits and exploration environments. 相似文献
15.
Marc A. Goossens 《Natural Resources Research》1993,2(1):14-30
For successful application of remote sensing and data integration in regional mineral exploration, it is crucial that, prior to regional application, relations between geological setting, mineralizing processes, related anomalies, and available remote sensing data are thoroughly studied in a calibration area with known mineralization that is representative for the region of interest. Recognizing features that are diagnostic for mineralization and its setting using Landsat Thematic Mapper (TM) and airborne geophysical data is complicated for the following reasons: (1) The basic relation between geology and the original data is often obscured by complex data manipulation, obstructing the understanding of the final output. (2) The risk of removing potentially important information during the data interpretation is considerable. (3) The decision criteria with respect to the correctness of classifications are often arbitrary. (4) Error and quality assessments are often subjective and not reproducible under different circumstances. A data integration study is presented for a 20-km×20-km calibration area in Spain with known granite-related mineralization. The contact metamorphic setting is diagnostic for most mineral deposits. Therefore, TM and airborne data are used to map features predictive for contact metamorphic rocks. A concept of spatial reasoning is presented that reduces the damage caused by these problems: (1) The data manipulation is very straightforward and aimed at recognizing specific features known to be diagnostic for the setting in which mineralization is likely to occur. (2) Every step in the data manipulation is described in a quantitative way. (3) The nature of the pixels surrounding a classified pixel is considered when deciding whether the classification is correct. (4) Weights are assigned to the degree of uncertainty within an interpretation. (5) Integrating the interpreted and weighed data into a probability map highlights zones that are confirmed by all data sets, and thus are most reliably classified. This concept enables users of a careful and systematic analysis of the multiple spatial data sets to detect diagnostic features that are predictive for granite-related mineralization in this region. 相似文献
16.
Robert D. Cairns 《Natural Resources Research》1998,7(3):233-244
The mineral investment decision under certainty is discussed in the context of broad microeconomic features of the industry,
the central one being that production is constrained by capacity. The assumptions of the economic literature on natural resources
are evaluated in the context of these features and the assumptions that permit the modeling of such facts are examined. Several
characteristics of extraction and equilibrium, and some implications of uncertainty, are considered. 相似文献
17.
基于RS和GIS的人口估计方法研究综述 总被引：13，自引：0，他引：13
随着RS和GIS技术的迅速发展, RS和GIS成为进行人口估计的主要手段。根据人口估计的目标和使用的数据源不同,可以把基于RS和GIS的人口估计方法分成两大类：面插值方法和统计模型方法。面插值方法根据插值过程中是否使用辅助数据可以进一步分成无辅助数据的面插值和有辅助数据的面插值两种。统计模型方法根据模型中自变量的不同可以分成建成区面积估计法、土地利用密度法、居住单元估计法、图像像元特征估计法和自然和社会经济特征综合估计法五种。本文按照上述分类标准综述了基于RS和GIS的各种人口估计方法,分析了各种方法的应用条件、优缺点和研究实例。最后提出了在基于RS和GIS进行人口估计方面需要进一步研究的问题。 相似文献
18.
Application of Data-Driven Evidential Belief Functions to Prospectivity Mapping for Aquamarine-Bearing Pegmatites,Lundazi District,Zambia 总被引：6，自引：0，他引：6
A case application of data-driven estimation of evidential belief functions (EBFs) is demonstrated to prospectivity mapping in Lundazi district (eastern Zambia). Spatial data used to represent recognition criteria of prospectivity for aquamarine-bearing pegmatites include mapped granites, mapped faults/fractures, mapped shear zones, and radioelement concentration ratios derived from gridded airborne radiometric data. Data-driven estimates EBFs take into account not only (a) spatial association between an evidential map layer and target deposits but also (b) spatial relationships between classes of evidences in an evidential map layer. Data-driven estimates of EBFs can indicate which spatial data provide positive or negative evidence of prospectivity. Data-driven estimates of EBFs of only spatial data providing positive evidence of prospectivity were integrated according to Dempster’s rule of combination. Map of integrated degrees of belief was used to delineate zones of relative degress of prospectivity for aquamarine-bearing pegmatites. The predictive map has at least 85% prediction rate and at least 79% success rate of delineating training and validation deposits, respectively. The results illustrate usefulness of data-driven estimation of EBFs in GIS-based predictive mapping of mineral prospectivity. The results also show usefulness of EBFs in managing uncertainties associated with evidential maps. 相似文献
19.
农业信息系统支持下的玉米遥感估产模型研究 总被引：6，自引：0，他引：6
在县级农业信息系统的支持下，分析了玉米遥感估产机理，提出了遥感获取玉米估产因子的原理 与方法，确定了近是玉米生长参数及评价玉米生态环境的遥感指数。在此基础上，分区，分阶段建立了玉米遥感综合估产模型。 相似文献
20.
基于SPOT-VGT NDVI的矿区植被遥感监测方法 总被引：7，自引：0，他引：7
以SPOT-VGT NDVI为遥感数据源,结合中国北方矿区环境特点,研究矿区植被和土地荒漠化的遥感监测方法,包括时间序列数据合成、植被变化趋势分析和土地荒漠化分级3方面.对每个像素的NDVI时间序列数据进行线性拟合,据直线斜率将NDVI变化程度分为7级;依据NDVI转换得到的植被覆盖度,将矿区土地荒漠化程度分为5级.以中国西北神东矿区为例,对该文提出的方法进行验证. 相似文献