Reappraisal of Legacy Reflection Seismic Data for the Prospection of Iron Mineralisation

Summary In this study, we demonstrate how the reappraisal of legacy reflection seismic data can be advantageous in the mineral exploration industry. The 130 km long seismic profile used in this study was acquired in 1994 for gold prospection and is opportunely located 10 km away from the Sishen open pit iron mine in South Africa. Reprocessing of the profile yields substantially improved imaging of subsurface structures such as faults and folds and better delineates metasediments hosting iron-oxide mineralisation. These metasediments are found at an average depth of 900 m with an average thickness of 500 m and are part of a broader synclinal feature that affects the general supracrustal package of the region. The syncline is controlled by near vertical faults and a major intrusion zone. In addition to the legacy seismic profile, other data such as outcrop, borehole, magnetic and magnetotelluric measurements are integrated to better interpret the subsurface and characterise the iron mineralisation beyond current mining ventures. Our findings, based on the cost-effective approach of legacy data reappraisal, provide foundational first-order models for potential mining developments in the future and demonstrate the value of legacy data despite their outdated acquisition parameters.