• Change Detection and Convergence Monitoring

    Improve the coverage, frequency and reliability of your monitoring program to enhance operational safety and mitigate production delays.
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  • Achieve greater visibility at scale to confirm stability

    In underground mining rock mass displacement 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.

    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.

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  • 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 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.

    The solution eliminates the need for data segmentation, manual alignment or third party software and requires minimal user input. This ultimately delivers 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 root cause analysis or identify 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.

    • Rapid data capture

      Rapidly capture current excavation profiles with Hovermap.

    • Streamlined workflow

      Process, align and visualize changes between two Hovermap scans​.

    • No 3rd-party software

      Eliminates complex and time-consuming 3rd party software for alignment of scans.

    • Large-scale monitoring

      Enables large scale and regular monitoring, delivering data to improve engineer decision making to reduce risk and hazard exposure.

    • Quantitative results

      Allows quantitative and repeatable interpretation of deformation across an entire excavation.

    • No need to segment data

      Compares scans of continuous 3D data at the same time. A non-rigid alignment process avoids segmentation to adjust for scan drift.

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  • Operational workflow

    1. Take your reference scan and a subsequent scan.​
    2. Process each scan with SLAM in Aura​.
    3. Roughly align the two point clouds and let Aura compare both datasets​.
    4. Interrogate the point cloud and mesh to see areas of movement between the two scans​.
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  • Improve your monitoring program

    Rapid insights with applications across every type of underground mine that can be fed into a range of engineering processes.

    • All Active Workings

      Monitor all excavation 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.

  • Applications

    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
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  • Whitepaper
    Focus your geotechnical monitoring where it counts

    Best practices to apply to optimize your convergence monitoring and change detection program. Download the whitepaper now.

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  • See the solution

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  • Frequently Asked Questions

    • Emesent’s Aura software allows the comparison of two scans, captured at different times, to identify change. After alignment of the two scans, a mesh is created from the reference scan and this is compared to the same area of the second scan, measuring the distance between the mesh and the second point cloud.

      The output provided is a .Laz point cloud with point to mesh distance attributes and a .Ply mesh of the reference scan. Change is determined relative to within the drive, easily differentiating convergence from divergence. Colour scales are used to visualize the distance between the two scans.

    • Emesent’s solution delivers an analysis-ready heatmap of time displacement across an entire mine. This can then be easily combined with other geological and geotechnical information to determine the root cause analysis or why that change is occurring, such as lithology, structural interpretations, seismicity data, and numerical modelling results showing stress and plastic strain.

    • Currently, the primary method for monitoring change in underground mining is damage mapping, which involves annotating two-dimensional cross-sections of the mine to indicate areas of concern. Although this method allows for broad spatial coverage, it is inherently subjective and lacks precision. In contrast, tape or digital extensometers offer high measurement accuracy at discrete points. However, due to the heterogeneous nature of rock masses—whose properties can vary significantly across tunnels, drives, and cross-sections—these point measurements are not always representative of broader conditions. Advanced tools like total stations and fixed laser sensors provide high accuracy but are limited in spatial coverage.

      Each of these traditional methods serves a purpose, yet they also come with trade-offs in terms of scale, frequency, and reliability. As a result, many underground mines struggle to monitor change effectively, potentially compromising both safety and profitability.

    • Integrating Simultaneous Localization and Mapping (SLAM) technology into existing monitoring strategies offers a way to overcome the aforementioned limitations of traditional methods. SLAM enables rapid, large-scale mapping of underground environments and can detect displacement with moderate to high accuracy. This yields more objective and quantitative data than traditional damage mapping.

      Moreover, SLAM can inform the targeted placement of extensometers by identifying zones of potential movement, thus enhancing the value of high-precision point measurements. While a total station may detect millimeter-level shifts in key infrastructure – such as a mine entrance – SLAM complements this by enabling broader environmental scans. Similarly, while a fixed laser sensor might track stability in a crusher chamber during stoping, SLAM extends coverage to adjacent areas. In this way, SLAM does not replace traditional tools but enhances them, supporting a more comprehensive, scalable, and proactive monitoring approach.

    • While conventional methods all contribute to an effective and robust geotechnical monitoring plan, they require a trade-off between coverage and accuracy. As a result it is difficult to understand where monitoring efforts should be focussed, with the attention placed only on the highest risk and exposure locations. SLAM technology allows the rapid scanning of the entire mine to establish a baseline. The spatial continuity of SLAM data means that now entire levels can be mapped, monitored, and interpreted. Although many mines have implemented SLAM technology into their monitoring plans, Emesent is the first to provide a combined data acquisition through to implementation solution.

    • Emesent is the first SLAM-based application that provides a Change Detection and Convergence Monitoring solution that combines data acquisition through to implementation. Uniquely, the solution eliminates the need for data transfer between multiple third-party software for the alignment and
      visualisation tasks necessary for change detection and convergence monitoring.

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