Electromagnetic Prediction for Concealed Orebodies

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Solution Overview

Problem

Conventional electromagnetic exploration methods for concealed orebodies, especially thin-layer ones, face challenges such as static shift corrections that filter out shallow anomalies and fail to fully utilize electromagnetic anisotropic characteristics, leading to a low success rate in predicting spatial locations and attributes of concealed orebodies.

Innovation Solution

An electromagnetic prediction method involving data acquisition, tensor impedance data processing, static shift recognition and correction, calculation of an electromagnetic recognition factor, and conversion to depth-resistivity information to improve the prediction of concealed orebodies by fully utilizing the correlation between electromagnetic data and spatial distribution patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional static shift correction methods are used, then the static shift is corrected, but the anomalies from shallow surface distribution are weakened or filtered out

Engineering Contradiction:
Improvestatic shift correction accuracyVSAvoidshallow anomaly information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the static shift correction process into two distinct parts: (1) a shallow anomaly detection step that identifies and preserves shallow anomalies before correction, and (2) a static shift correction step that corrects the shift without affecting the previously identified shallow anomalies. This segmentation allows both shallow anomalies and static shift correction to be handled separately, preventing the loss of shallow anomaly information during correction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary detection and marking of shallow anomalies before applying static shift correction. By identifying shallow anomalies in advance and applying protective measures (such as setting protection flags or adjusting correction parameters in the marked areas), the correction process can proceed without filtering out these important shallow anomalies. This preliminary action ensures that shallow anomaly information is preserved throughout the correction process.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If optimal curves are selected from E polarization (TE), H polarization (TM) or geometric average, then the inversion profile is formed, but the electromagnetic anisotropic characteristics correlation with extended concealed orebodies is not fully utilized

Engineering Contradiction:
Improveinversion profile formationVSAvoidelectromagnetic anisotropic characteristics information
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent extends the analysis from traditional two-dimensional (TE and TM modes) to three-dimensional electromagnetic anisotropic characteristics by introducing azimuthal dependence. The method calculates apparent resistivity and phase differences in multiple azimuthal directions, thereby utilizing the electromagnetic anisotropic characteristics that vary with orientation. This dimensional extension allows full utilization of the correlation between electromagnetic anisotropy and the spatial distribution of extended concealed orebodies.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the parameter set from simple TE/TM mode selection to a comprehensive set of parameters including apparent resistivity, phase difference, and their azimuthal variations. By calculating these parameters in multiple directions and analyzing their anisotropic characteristics, the method fully utilizes the electromagnetic response information related to the orientation and extension of concealed orebodies, rather than relying on a single optimal curve selection.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional prediction methods are used, then the exploration process is simple, but the success rate of predicting spatial locations and attributes of concealed orebodies is low

Engineering Contradiction:
Improveexploration process simplicityVSAvoidprediction success rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces conventional mechanical/inversion-based prediction methods with an electromagnetic anisotropic characteristics-based prediction approach. Instead of relying solely on traditional inversion of apparent resistivity curves, the method uses the calculated parameters (apparent resistivity, phase difference, and their azimuthal variations) directly to predict the spatial locations and attributes of concealed orebodies. This substitution maintains operational simplicity while significantly improving prediction reliability by utilizing directional electromagnetic response information.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enhances the success rate of predicting concealed orebody locations and attributes by accurately correcting static shifts and utilizing anisotropic characteristics, ensuring that recognition information is not influenced by static shifts, thereby improving the accuracy of orebody predictions.

Implementation Method 1

observing electromagnetic fields in a survey line direction and a direction perpendicular to the survey line direction at a same survey point

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11105949B2Electromagnetic prediction method for concealed mines
Publication Date: 2021.08.31 INSTITUTE OF GEOLOGY AND GEOPHYSICS CHINESE ACADEMY OF SCIENCES
  • US11105949B2 patent drawing
  • US11105949B2 patent drawing
  • US11105949B2 patent drawing

AI summary

Disclosed is an electromagnetic prediction method for concealed orebodies. A factor associated with an observation direction and a factor associated with a frequency are retrieved from tensor impedance data after static shift recognition and correction. An electromagnetic recognition factor including anisotropic characteristics is constructed. A probability of a developed orebody in a particular underground depth range of a target area is then inferred by using the electromagnetic recognition factor alone or as a component of comprehensive prediction information. Due to the full use of a potential correlation between anisotropic characteristics of frequency domain electromagnetic fields and an apparent metal factor and two-dimensional (or three-dimensional) extended concealed orebodies, the success rate of predicting spatial locations and attributes of the concealed orebodies is improved.