Change detection and convergence monitoring

Improve the coverage, frequency and reliability of your monitoring program to enhance operational safety and mitigate production delays.


In underground mining displacement and movement of rock from an excavation can have significant consequences, from injuring personnel to causing unscheduled delays, with the subsequent cost implications. In a mine you can rarely predict where things are going to change dramatically, therefore the ability to efficiently and effectively monitor change and convergence across the whole excavation is vital to safeguard against incidents and mitigate impacts on production and therefore profitability. 

However, only a fraction of the cubic kilometers affected by the mining process are observable through drill holes or excavation fronts and therefore capturing sufficient data to be able to confirm that all areas of an excavation are stable can be challenging. Additionally, processing the data to achieve analysis-ready outputs is a highly time consuming and manual process. As a result, many mining operations are falling short in the frequency and extent of their monitoring efforts, often unable to meet the standards they aspire to or that are necessary for optimal safety and operational efficiency.

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The limitations of traditional methods

Currently, the predominant method for assessing change in underground mining is damage mapping, which entails annotating two-dimensional section views of the mine to highlight areas of damage. While this approach allows for coverage of a considerable area, it is subject to human error. Alternatively, tape or digital extensometers are used to measure specific points within the mine. Although these devices offer high levels of accuracy, due to the heterogeneous nature of rock masses, which exhibit varying properties across different locations within drives, tunnels, or cross-sections, the results cannot represent change across an entire excavation. More advanced technologies such as total stations or fixed laser sensors are highly accurate, however, they are constrained by limited coverage capabilities.

While each of these methods has its place, they also have their limitations. As a result, many underground mines fall short in the scale, frequency and reliability of their monitoring efforts, putting safety and profitability at risk.

Complementing traditional methods with SLAM

Complementing traditional practices with a SLAM methodology allows the implementation of an improved overall monitoring plan. For example, SLAM can quickly map an entire mine and identify displacement with moderate to high accuracy. This provides more accurate and quantitative data than damage mapping. When it comes to tape extensometers, a SLAM map of an entire mine will allow you to pinpoint exactly where to use an extensometer in future to confirm that displacement. Or a total station could be used to identify change regarding specific infrastructure, for example a 1-2mm (about 0.08 in) shift at a mine entrance, but SLAM complements this by scaling to rapid mapping of large areas. Similarly, a fixed laser could be used to ensure a crusher chamber is not moving too much during stoping for example, but SLAM can be used to cover a wider area.

While many mines have used SLAM technology to scan the entire site and establish a baseline, alignment of these scans is a time consuming and manual process that usually requires the use of complex third-party software.

How to improve your monitoring program

Emesent’s Change Detection and Convergence Monitoring solution combines rapid capture mobile SLAM technology with a faster, easier and more repeatable processing workflow. This enables mining operators to scan excavations over a larger area more regularly and monitor change using accurate, quantitative data.

Rapid data captureStreamlined workflowNo 3rd-party software
Rapidly capture current excavation profiles with Hovermap.Process, align and visualize changes between two Hovermap scans​.Eliminates complex and time-consuming 3rd party software for alignment of scans.
Large-scale monitoringQuantitative resultsNo need to segment data
Enables large scale and regular monitoring, delivering data to improve engineer decision making to reduce risk and hazard exposure.Allows quantitative and repeatable interpretation of deformation across an entire excavation.Compares scans of continuous 3D data at the same time. A non-rigid alignment process avoids segmentation to adjust for scan drift.

The streamlined capture and analysis workflow delivers rapid insights that have applications across every type of underground mine and can be fed into a range of engineering processes.

All active workings

Monitor all excavations to check stability and ensure a safe workplace.

Frequent stope blasting

Check the condition of oredrives, brows and high exposure excavations.

Caving operations

Rapidly identify large stress changes and monitor long-life excavations.

Deep / high stress mines

Monitor for ongoing change around discontinuities, large structure and bulking surface support.

Mines in active seismic areas

Back analysis, identification of post-event changes.

Internal enclosed spaces

Check for change in crib rooms, crusher chambers, conveyor drives and portals.


Emesent Aura supports Change Detection and Convergence Monitoring for the following:

  • Convergence monitoring (gross/net displacement)
  • Convergence monitoring (rate)
  • Discontinuity mobilization (shear zones, faults, large-scale structure)
  • Brow damage after firing or mucking
  • Forensically analyzing rock bursting and seismic damage

  • Depth of damage
  • Ground support performance and residual capacity
  • Interactions between adjacent and overlying levels
  • Mine scale instability recognition
  • Tracking rehabilitation


The Emesent Solution

Optimized for enclosed spaces and underground mines, and applicable to both hard rock (change detection) and soft rock (convergence monitoring) mines, Emesent’s solution delivers a simplified, easy to use workflow without the need for data segmentation or manual alignment, making it ideal for long scans such as raises. Eliminating the need for third party software and minimizing the need for user input, it ultimately delivers a faster, more efficient workflow and more repeatable, quantifiable outputs on where change or dilation is occurring and the velocity of this change over a large area. This can then be combined with other data to determine the root cause analysis or why that change is occurring, allowing for more regular and widespread monitoring of change, helping engineers – from geotechs to surveyors – to make more informed decisions and reduce risk.

How it works

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