Potential-field geophysical data inversion for 3D modelling and reserve estimation (Example of the Hajjar mine, Guemassa massif, Morocco): magnetic and gravity data case

IF 2 4区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY
Saâd Soulaimani, S. Chakiri, A. Manar, Ayoub Soulaimani, A. Miftah, M. Bouiflane
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引用次数: 3

Abstract

Geophysical data inversion is a tool, which can be used to recover the subsurface distribution of physical properties from field data. Each type of geophysical data can be inverted using one or more inversion algorithms. In this paper, a set of geophysical magnetic and gravity data of the Hajjar area in Morocco, covering an extent of 3.2× 1.6 km2, were used to make a 3D model of an orebody and to estimate the mineral reserve by potential-field geophysical data inversion and excess mass estimation. We thus promote the development and application of potential-field geophysical data inversion using the softwares Geosoft Oasis Montaj and Voxi Earth ModellingTM and the evaluation of its power compared to the excess mass estimation method. The process of inversion begins with data processing, then moves to analysis and interpretation, and ends with unconstrained Cartesian cut cell inversion. The results show a variation of −0.22 mGal to 1.59 mGal for the gravity residual anomaly map, leading to have density variations from 2.45 g/cm3 to 4.22 g/cm3, and a variation of −232 nT to 1018 nT for the reduced magnetic anomaly map. Moreover, data inversion allowed us to create a 3D model of the orebody and of the adjacent geological formation, and to estimate the different parameters that characterize the orebody derived from the inversion results, which have been confirmed from survey data: (depth ≈ 160 m; maximum ∗Corresponding author. ISSN (electronic) : 1778-7025 https://comptes-rendus.academie-sciences.fr/geoscience/ 140 Saâd Soulaimani et al. density ≈ 4.22 g/cm3; minimum density ≈ 3 g/cm3; mean density ≈ 3.61 g/cm3; thickness of the overburden ≈120 m; dip ≈ 45◦; morphology ≈ lens; volume ≈ 4.8×106 m3). It was therefore possible to evaluate the reserve, and to validate the reliability of the inversion by having a root mean square error between the exploited reserve and the calculated reserve of 13.5%, i.e. an insignificant difference between the real and calculated magnetic and gravity orebody responses, which support the validity of the results.
三维建模和储量估算的位场地球物理数据反演(以摩洛哥Guemassa地块Hajjar矿为例):磁重数据案例
地球物理数据反演是一种从野外数据中恢复地表物理性质分布的工具。每种类型的地球物理数据都可以使用一种或多种反演算法进行反演。本文利用摩洛哥哈贾尔地区一组3.2×1.6km2的地球物理磁、重数据,建立了矿体的三维模型,并通过势场地球物理数据反演和过剩质量估计来估计矿产储量。因此,我们推动了利用Geosoft Oasis Montaj和Voxi Earth ModellingTM软件进行势场地球物理数据反演的开发和应用,并与超质量估计方法进行了功率评估。反演过程从数据处理开始,然后进入分析和解释,最后以无约束笛卡尔剪切单元反演结束。结果显示,重力残余异常图的变化范围为-0.22 mGal至1.59 mGal,导致密度变化范围为2.45 g/cm3至4.22 g/cm3,而还原磁异常图的密度变化范围则为-232 nT至1018 nT。此外,数据反演使我们能够创建矿体和相邻地质构造的3D模型,并根据反演结果估计矿体的不同参数,这些参数已从调查数据中得到证实:(深度≈160 m;最大值*通讯作者。ISSN(电子版):1778-7025https://comptes-rendus.academie-sciences.fr/geoscience/140 Saâd Soulaimani等人,密度≈4.22 g/cm3;最小密度≈3 g/cm3;平均密度≈3.61g/cm3;覆盖层厚度≈120m;倾角≈45◦; 形态学≈晶状体;体积≈4.8×106 m3)。因此,可以评估储量,并通过开采储量和计算储量之间的均方根误差为13.5%来验证反演的可靠性,即实际和计算的磁性和重力矿体响应之间的微小差异,这支持了结果的有效性。
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来源期刊
Comptes Rendus Geoscience
Comptes Rendus Geoscience 地学-地球科学综合
CiteScore
2.80
自引率
14.30%
发文量
68
审稿时长
5.9 weeks
期刊介绍: Created in 1835 by physicist François Arago, then Permanent Secretary, the journal Comptes Rendus de l''Académie des sciences allows researchers to quickly make their work known to the international scientific community. It is divided into seven titles covering the range of scientific research fields: Mathematics, Mechanics, Chemistry, Biology, Geoscience, Physics and Palevol. Each series is led by an editor-in-chief assisted by an editorial committee. Submitted articles are reviewed by two scientists with recognized competence in the field concerned. They can be notes, announcing significant new results, as well as review articles, allowing for a fine-tuning, or even proceedings of symposia and other thematic issues, under the direction of invited editors, French or foreign.
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