Magnum Mining & Exploration (ASX: MGU) has defined a significant Exploration Target for its Buena Vista Green Pig Iron Project in Nevada, USA.
The Exploration Target Estimate is approximately 407Mt to 540Mt at 15% to 22% iron (Fe), exclusive of the existing Indicated and Inferred Resources of 232Mt @18.6% Fe (JORC 2012), announced in March 2021.
The potential quantity and grade of the Exploration Target Estimate is conceptual in nature, there has been insufficient exploration to estimate a Mineral Resource over the entire area of the Exploration Target, and it is uncertain if further exploration will result in the estimation of an increased Mineral Resource.
The Buena Vista iron resource consists of magnetite that ranges in grade from less than 10% Fe, the cut-off used in the resource estimation, to over 60% Fe.
The Buena Vista Green Pig Iron Project is covered by a high definition, helicopter-borne aeromagnetic survey, as announced on 7 November 2022. This data is used to model the causative magnetic bodies that could give rise to the observed magnetic anomalies by dividing the earth into voxels. The voxels are assigned magnetic susceptibilities in an iterative manner until the theoretical magnetic anomalies caused by those susceptibilities match the observed ones.
Once a 3D map of susceptibilities is obtained, zones of susceptibilities that are over some chosen magnetic susceptibilities are defined and the volume encompassed by that isosurface calculated.
The choice of the magnetic susceptibility isosurface is made both on the basis of magnetic susceptibility logging and calibrating the models against existing MREs where available. The resources at East, West, and Section 5 deposits were used for this calibration. Both methods indicated that a value of 0.1 SI provides the best correlation between the magnetic model and the known resources while at the same time corresponds with an iron grade of approximately 10%, the cut-off used for the existing Indicated and Inferred resources.
This 0.1 SI isosurface is cut off at a depth of 250m below ground level to restrict the model’s depth extent to a practically mineable depth. In addition, small volumes, representing minor magnetic anomalies, were ignored as likely being of insufficient size to mine.
A density of 2.79 t/m3 was used to convert the model volume to a tonnage. This density is calculated from the density – ore grade curve used in the MRE and represents an 18% Fe grade.
The final model is then referred back to existing drill hole information, geological mapping, and the aeromagnetic data to ensure it complies with those datasets.
The ETE tonnage is deemed to be accurate within +/-25%. Iron grades reflect those already defined in the existing MRE.
The company has planned a prioritisation of targets for follow-up by drilling, based on potential size and distance from the Buena Vista Mine area, with activities to be completed during 2023.
“The collection of high-resolution aeromagnetic data, and the re-interpretation that has enabled, has shown that the Buena Vista area has the potential to grow its iron resources significantly. This Exploration Target Estimate provides investors with the comfort that Magnum may control iron resources that could prove to be one of the largest in the USA outside the Lake Superior iron district,” CEO Neil Goodman said.
For further information please visit: https://www.mmel.com.au/
