August 17, 2024

VALE BASE METALS

Muon Tomography for Mine Extension

High-resolution imaging of density anomalies consistent with known semi-massive sulphide mineralization, delineating lateral and vertical extension of known geology, as well as transition zones, strongly correlated with the mineralization shell.

Download Full Case Study

Totten Mine

PROJECT

Sudbury, Canada

LOCATION

Borehole

IDEON DETECTOR TYPE

Semi-Massive Sulphide (Nickel-Copper-PGE)

DEPOSIT TYPE

Highlights

The unconstrained analysis, later validated with drill data and geological modelling provided by Vale Base Metals, provided high-resolution geological insights throughout the survey area, demonstrating the capability of the Ideon platform even in contexts where there is little prior knowledge.

  • Mapped geologic structures to within 5 m spatial resolution across a volume of 130 million m3 at one time, giving the Vale Base Metals team confidence in their understanding of a large zone target quickly, and important inputs for critical mine-planning decisions.
  • Imaged a large volume of earth around an active mine site with minimal operational or surface disruption, avoiding productivity loss and environmental impact on site.
  • Identified a historic rubble zone adjacent to the mineralization target, delineating a zone of technical interest to help aid in geotechnical de-risking.
  • Demonstrated how Vale Base Metals could have feasibly saved a third of the drilling cost and several years’ time in getting to a high-resolution understanding of this target zone — using only three drillholes.

BACKGROUND

Located just outside of Sudbury, Ontario, the Totten mine opened in 2014 (after operations were suspended since 1972) with a 20-year projected mine life.

The Totten deposit is situated along the Worthington Offset, one of the fractures resulting from the creation of the Sudbury Basin 1.8 billion years ago, when a comet punctured Earth’s crust, allowing material from the mantle to well up and fill the basin with melted rock. The deposit consists of semi-massive sulphides hosted in a narrow quartz-diorite dyke. It comprises a blend of lower grade metals and high-grade bands throughout.

IDEON SOLUTION

Ideon provided Vale Base Metals with a full-service imaging program, including customized deployment design and modelling to ensure optimal outcomes, turnkey equipment bundling and installation logistics, continuous imaging with regular updates to show progressive resolution improvement, remote monitoring and diagnostics, geoscientific analysis and interpretation, and onsite results immersion.

The objective of the study was to demonstrate muon tomography in an area where the geological model was well understood, helping to delineate the Totten deposit as part of mine-life extension work. Ideally, the survey would help Vale Base Metals determine the lateral and vertical extent of the mineralized zone, as well as delineate the transition/edges. The primary volume to explore was the area upward from existing known mineralization.

Ideon deployed 16 borehole detectors in three sensor arrays, down three drillholes emanating from a single pad on the Totten site. The detectors were situated from approximately 200 m to 400 m deep and gathered data over a period of 6 months. Data intake and analysis were conducted remotely via 4G link to verify quality and calibration, and to develop radiographic images of subsurface density anomalies with continuously improving clarity.

Sixteen borehole detectors were deployed down three drillholes. The target mineralization shown (blind throughout the project) is shown as the red surface. The volume of highest sensitivity to small 10 m thick structures is shown as the semi-transparent surface.

Ideon then delivered a robust 3D density model of the target area using muon data without any constraining geological information. This was a blind, unconstrained data analysis, but Vale Base Metals had already mapped the area with >100 drillholes. After the delivery of the 3D density model, results were mapped to the Vale geological model to validate outcomes.

“The value for us lies in reducing the amount of drilling we do to understand subsurface environments, getting a broad understanding of large target zones quickly and moving straight to validation. This helps us advance projects faster while ensuring that we fully understand the subsurface target area and don’t compromise on our environmental objectives.”
Darren Hodder
Manager, North Atlantic Long-Term Geology & In-Mine Exploration

Discover the outcomes at Totten

This project proved the capability of muon tomography in 3D mapping subtle mineralization regions with far better resolution than other geophysical methods. Additionally, this project demonstrated the low-impact nature of the Ideon muon tomography technology, resolving a large volume of earth at high resolution from a single drill pad.

Download the full case study for detailed content and analysis at the Totten project.