Journal of Geology & Geophysics
Open Access

Mining Geophysics Enhancing Subsurface Exploration and Ore Deposit Detection Efficiency

Maysam Abedi^{* *}Correspondence: Maysam Abedi, Department of Mining Engineering, College of Engineering, University of Tehran, Iran, Email:

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Description

Mining geophysics is a vital subdiscipline of applied geophysics that uses physical measurement techniques to locate, map, and characterize mineral deposits buried beneath the Earth’s surface. It plays a critical role in all stages of the mining cycle from exploration and resource evaluation to mine planning and environmental monitoring. Through the use of non-invasive technologies, mining geophysics allows geologists and engineers to investigate geological formations indirectly, significantly reducing the costs and environmental impact associated with extensive drilling and excavation.

The core objective of mining geophysics is to identify anomalies in the physical properties of rocks that could indicate the presence of economically valuable minerals such as gold, copper, iron, lead, zinc, and rare earth elements. These physical properties include density, magnetic susceptibility, electrical conductivity, resistivity, and seismic velocity. Different geophysical techniques are selected based on the nature of the target deposit, the geological environment, and the depth of investigation required.

Magnetic surveys are among the most commonly used methods in mining geophysics, particularly for exploring regions with iron-rich minerals or magnetite-bearing formations. These surveys detect variations in the Earth’s magnetic field caused by magnetic minerals in the subsurface. Airborne magnetic surveys are often employed in the early stages of exploration to cover large areas quickly and identify zones of interest. Ground magnetic surveys follow up in more detail, especially in areas where subtle anomalies may indicate hidden ore bodies or structural features such as faults and shear zones that control mineralization.

Gravity surveys measure variations in the Earth’s gravitational field, which reflect changes in the density of underlying rock formations. High-density ore bodies such as massive sulfides or iron ore can be detected through gravity anomalies. Gravity data is particularly useful in regions with minimal magnetic response or where mineral deposits are located beneath thick overburden. Advances in instrumentation have made both ground and airborne gravity surveys more precise and capable of detecting deeper and smaller targets.

Electromagnetic (EM) and electrical resistivity methods are also widely used in mining exploration, especially for detecting conductive mineral deposits such as copper sulfides, graphite, and nickel. EM surveys generate time-varying magnetic fields that induce electrical currents in conductive materials underground. These currents produce secondary magnetic fields, which are measured by sensors to map subsurface conductivity. Time-domain and frequency-domain EM systems are applied in both ground and airborne configurations, enabling rapid assessments across diverse terrains.

Resistivity methods involve injecting electrical current into the ground and measuring the resulting voltage differences to calculate the resistivity of subsurface materials. This technique helps identify contrasts between conductive ore bodies and their surrounding rocks. Electrical Resistivity Tomography (ERT) provides high-resolution images and is particularly useful in complex geological settings where detailed cross-sectional views are needed to define ore zones or guide drilling.

Induced Polarization (IP) is a specialized electrical method used extensively in mining geophysics to detect disseminated sulfide minerals. In an IP survey, electrical current is introduced into the ground and then switched off. The delayed voltage decay is measured and used to determine chargeability, a property indicative of the presence of metallic minerals. IP is often combined with resistivity surveys to improve interpretation and pinpoint areas with high mineral potential.

Seismic methods, though less common in mining compared to oil and gas exploration, are increasingly applied for mine planning, geotechnical investigations, and deep exploration. Seismic refraction and reflection techniques provide information on rock layering, structure, and mechanical properties. In hardrock environments, seismic surveys assist in detecting faults, fractures, and lithological boundaries that influence the distribution of ore bodies. Seismic velocity contrasts can also help differentiate between mineralized zones and barren rock.

The integration of multiple geophysical methods is a key strength of mining geophysics. Each technique provides different types of information, and their combined use leads to a more accurate and comprehensive understanding of the subsurface. For example, combining magnetic and EM data can help distinguish between magnetic but non-conductive rocks and conductive but non-magnetic mineralization. Such integration improves the success rate of exploration programs and reduces the risk of expensive drilling failures.

Mining geophysics does not end with exploration. During the development and production phases, geophysical methods are used to guide excavation, monitor structural integrity, and ensure the safety of mining operations. Ground Penetrating Radar (GPR) and micro seismic monitoring are employed in underground mines to detect voids, monitor rock movement, and assess support systems. In open-pit mines, geophysical techniques assist in slope stability analysis and groundwater management.

Environmental monitoring and mine closure are also supported by geophysical methods. Detecting and tracking mine-related pollution, such as acid mine drainage or leachate migration, is essential for regulatory compliance and environmental stewardship. Techniques like ERT, EM, and GPR help monitor contaminant spread, evaluate containment structures, and assess the effectiveness of remediation efforts.

With the increasing demand for minerals to support global infrastructure, renewable energy, and advanced technologies, mining geophysics is becoming more important than ever. Innovations in sensor design, data acquisition, and interpretation software are making geophysical surveys faster, more accurate, and more cost-effective. Machine learning and artificial intelligence are beginning to play roles in pattern recognition and anomaly detection within large datasets, further enhancing exploration efficiency.

Conclusion

In conclusion, mining geophysics is an indispensable tool for modern mineral exploration and resource management. Its ability to provide detailed, non-invasive subsurface insights reduces environmental impacts, lowers exploration costs, and increases the chances of successful discovery. As the mining industry evolves to meet new challenges and demands, the role of geophysics will continue to expand, supporting responsible and sustainable resource development around the world.