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How Barberton Mines are using handheld LiDAR to improve efficiency and promote safety

Location

Mpumalanga, South Africa

Scan time

Approx. 10-15 minutes per scan

Size

Size differ per solution

Scanned

Barberton Mines

Industry

Mining

Mining in South Africa

The mining industry in South Africa contributes R350 billion to the economy annually, with an estimated R35 trillion of resources left to mine. Mining companies in Africa and across the globe are continually reviewing their ways of working and best practices for mining safely, efficiently, and sustainably. Research and development play a big role in these changes, with early adopters of new technologies benefitting the most. 

Barberton Mines has been operational for 130 years and is located in Mpumalanga, South Africa. Consisting of several mines, including Fairview, Sheba, and New Consort, they produce ± 80,000 oz of gold annually. In recent years, Barberton has evaluated new technologies to make its mining processes fast, safe, and cost-effective.

One of the ways in which Barberton Mines investigated new technologies, was by finding ways to improve their survey workflows. They adopted static-based LiDAR solutions to produce accurate 3D models and became one of the first users of handheld SLAM solutions in 2014. 

Why did they choose handheld SLAM?

While static-based scanners are highly accurate, the survey team at Barberton Mines needed a quick and versatile solution for the variety of mining methods employed on the different mines and ore-bodies. The goal was simple; to accurately and safely capture data daily for ongoing analysis of the mining production. In addition, they needed a solution that could easily handle the rugged terrain and environment that mines are so often known for.

Barberton Mines chose to reassess their underground mapping technology to improve the speed and accuracy of their survey operations and increase productivity in the mines. 

How GeoSLAM fits in at Barberton Mines

Barberton Mines was the first mine in Sub-Saharan Africa to use GeoSLAM technology when they purchased a ZEB1 in 2014. The results and continued success on the mine prompted them to invest in 4 ZEB Revo’s in 2019, which are still in use today.

The ZEB Revo is lightweight and accurate, making it the perfect tool for surveying. The survey team can complete scans of the mines in half the time, and the process is repeatable. These capabilities have contributed to Barberton Mines streamlining their workflows, long-term cost savings, and greater returns on investment. 

The scanner’s ease-of-use only requires one person on-site to capture data. Furthermore, it doesn’t require professional training to use the equipment so operators can capture data in parts of the mine that surveyors cannot access for safety reasons. This casts a virtual eye on areas of the mine previously unseen by the surveyors and creates an opportunity to review old tunnels.

Finally, the lack of extensive training required to learn how to operate the scanner benefits new employees and the mine in general. It takes less than an hour to learn how to use the equipment and to process the final point cloud data, allowing surveyors to spend more time assessing final deliverables and finding ways to improve efficiencies in the mining process.

GeoSLAMs scanners have exceeded our expectations and have helped to achieve our goals where other mapping methods could not.”
– Thys Smith, Chief Surveyor at Barberton Mines

Solutions

Having originally invested in handheld scanners for underground mapping, Barberton Mines have since adopted the technology for other applications, further increasing their return on investment. The scanners are now operating across three key aspects of Barberton’s mining process.

Production Progress Mapping

The original and most common use for scanning is Production Progress Mapping. Barberton completes daily scans of the mines, bringing the data back for regular analysis of production progress mapping. 

The scanned areas are approximately 300 m3 and using GeoSLAM technology, they can scan large areas in about 10-15 minutes. In addition, because the scanners are handheld, production at the mine isn’t compromised by having to stop miners from doing their jobs while scanning is in process. 

Using the ZEBs, surveyors no longer need to be underground for extended periods, unlike previous methods. They begin their scans in a safe area, proceed to the mining faces, and finish back in the safe area while capturing the data needed – a completely repeatable and efficient process.

Stockpile Measurements

Barberton Mines has 5-6 stockpiles that make up 4000 cubic tons of material. They frequently measure the volume of these stockpiles, to ensure they have accurate and up-to-date information on their resources. 

Simply walking around the stockpiles with a scanner and importing the data into 3rd party software, provides the survey team with all the information they need to produce required reports. 

Health and Safety

One example of where scanning has improved health and safety is the mapping of transport shafts. To comply with safety regulations, surveyors frequently scan the shafts to look for rock movement or deformation that might require further investigation. 

They found that scanning tunnels from the chairlift with a handheld scanner was quicker than previously used conventional methods, like Terrestrial Laser Scanning (TLS) or by hand. Handheld scanners only require the operator to ride the chairlift down- and back up again, without interfering with production.

The scanners are frequently used in these applications and their robust nature means they have never needed repair or maintenance.

Conclusion

Fast, efficient, and accurate data capture from GeoSLAMs handheld LiDAR scanners have proven to be a huge benefit for Barberton Mines. The repeatability of the scans has provided a great return on investment and the durability has meant that despite being used in challenging environments, the scanners have endured. The increased speed of data capture has led to safer work practices for the surveyors, and the walk-and-scan method has resulted in no disruption to the daily work of the mines.

With the scanner’s versatility, the survey team is still finding new applications where the technology can be utilised in the mining environment.

It is paramount for us to understand our client’s needs, especially in the ever-changing environment of mining. GeoSLAM provided the ultimate mapping solution that best addressed those needs, resulting in improved accuracy and overall productivity.”
– Gustav Fick, SME – Subject Matter Expert UAV & 3D Scanning at OPTRON




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    GeoSLAM Sample Data

    View and download data in our free point cloud viewer

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    Vent Shaft

    Location: United Kingdom
    ZEB Scanner: ZEB Revo RT

    This data was captured using GeoSLAM’s ZEB Cradle accessory.

    Would you like to see a specific dataset that’s not on this page? Contact [email protected]

    One scanner, many solutions

    Boulby mine was one of the first in the world to use SLAM technology, having adopted GeoSLAM’s ZEB1 into their workflow, in 2013. Nowadays, the mine operates GeoSLAM ZEB Horizons for most of their survey needs.

    On-demand Webinar

    Watch a previous webinar in your own time

    Using GeoSLAM technology to improve Mine Productivity

    Hosted by GeoSLAM dealer Optron and GeoSLAM’s Global Head of Mining Owen Howells. This webinar focuses on Mining Applications and how SLAM technology can be used to quickly and effectively map the existing mining operations. Showcasing the workflow from capturing the data using the ZEB Horizon 3D laser scanner to generating a georeferenced point cloud in GeoSLAM Connect and ultimately getting to the final deliverable. 

    Includes use cases directly from GeoSLAM customers.

    Referencing using control points

    Control points are points within a given area that have known coordinates. They are a key tool in the geospatial industry and can be utilised in a variety of ways, including georeferencing point clouds and aligning aerial images to terrestrial data. By using control points, surveyors are able to accurately map larger areas and position overlapping surveys of an area together. They can also be used in non-geospatial industries, such as construction and mining, to show clear temporal comparisons between multiple surveys of the same area. This method of georeferencing is also referred to as adjust to control.

    Previously, checkerboards and spherical targets have been used as control markers – these items are captured in surveys and can be identified for georeferencing or aligning. The main drawback with these methods is that they rely heavily on human interpretation when processing, meaning that the processed datasets may be susceptible to an increased amount of error.

    When capturing handheld surveys, GeoSLAM systems are able to collect reference points. These can then be matched with known control points to reference scans and increase the level of accuracy.

    What makes GeoSLAM referencing different?

    • More accurate: GeoSLAM scanners are used with known control points and survey grade pins, rather than more traditional moveable targets. This reduces the margin of error within point clouds.
    • Save time: using known survey control points means there is no need to manually position individual targets before every scan. Data capture can then be repeated regularly, faster, easier and with no concerns that reference points are captured in different places each time.
    • Safer: in dangerous or inaccessible areas, targets are not required to be physically positioned on pre-defined control points prior to each scan. This reduces the time exposed to hazards and unsafe areas.
    Geospatial

    Geospatial

    Easily reference point clouds and produce reports highlighting accuracy values.

    Utilities

    Mining

    Regularly monitor site operations (e.g. stockpiles) and hazards.

    Security & Defence

    Construction

    Compare changes over time and map progress onto predetermined CAD/BIM models.

    Capture

    All GeoSLAM ZEB systems are able to capture reference points using the reference plate accessory. These reference points can simply be measured by remaining stationary for periods during a scan and will be recognised during the processing stage. Points can be captured from a horizontal or vertical position, depending on which ZEB system is used, making it easier than ever to georeference datasets.

    Process

    Using the Stop & Go Georeferencing workflow in GeoSLAM Connect, datasets can be automatically referenced through a rigid or non-rigid transformation.

    Scans are rotated and adjusted and reference points are matched to the known control points without changing the scale factor. A single transform is applied to every data point in the point cloud.

    The scale factor of datasets is altered to suit the control points – every data point is moved to a new position; this means the relative positions of these points also changes. This method is better suited for poor SLAM environments.

    A clean georeferenced point cloud is produced using both methods. An accuracy report of the transformation is also generated and includes an RMS error value.

    Once georeferenced using control points, point clouds can be optimised further using leading third party software:

    • Comparisons with existing CAD/BIM models
    • Point cloud to point cloud registration showing changes over time within a given area
    • CAD/BIM model creation

    For more information about our third party partnerships, head to our integrations page.

    Mapping hazardous mines under intense time constraints

    Beck Engineering, an Australian mining engineering consultancy specialising in mining and rock mechanics analysis, needs to rapidly map mines under intense time constraints using versatile technology which is adaptable to any environment. GeoSLAM’s handheld mobile mapping solution was chosen as it is compact, portable and delivers a high level of accuracy. With GeoSLAM’s “go-anywhere” 3D technology in hand, Beck Engineering has been able to supply invaluable data regarding the direct effects of mining to better understand the implications of a deforming rock mass. Beck Engineering is now able to accurately measure the shape of an excavation or tunnel over time. As a result, tunnels are safer, better designed and more cost efficient.

    We have continued to use GeoSLAM products as they have proven to be affordable, lightweight and sufficiently robust devices for their application underground. GeoSLAM continues to produce a high-quality device that is at the forefront of practical mobile laser scanning devices.
    – Evan Jones, Senior Rock Mechanics Engineer at Beck

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      Blogs

      Keep up to date with the latest news and thought leadership from GeoSLAM.

      Mapping the Underground World

      Critical technology for intelligent mines

      The future of underground mining

      The way we work is changing. Advanced technology tools are transforming the way we collaborate, analyse, organise and innovate. In just about every sector, the tech advance is helping organisations be more productive, save time and money and work better together. And the mining industry is no different – only that it lags behind. (1)

      With increased competition, the pressure is on. Around the world, mining operators across all commodities are facing the combined challenges of declining ore grades and operating efficiency. With the decreasing availability of tier one assets, and continued focus on shareholder returns, operators are looking towards digital tools and new ways of working to drive results.

      The digital revolution can transform and automate the entire mining value chain from ‘pit to customer’. Advanced supply chain visualisation tools can aggregate data from multi-systems to show near-real-time operations metrics; drones can help with geotechnical monitoring and remotely conduct stockpile volumetric audits; and powerful laser scanners can build highly accurate 3D maps of underground mines in minutes.

      The last decade has seen the rollercoaster of highs and lows in the mining sector; and the volatility is likely to continue.(2) While digital tools are readily available that help mining decision-makers do the job better, faster, safer and more cost effectively, there are still many businesses slow to embrace transformative practices. With change being a constant, forward- thinking mining operators need to embrace digital technology and drive innovation, or risk being left behind.

      As the mining industry’s value proposition is increasingly called into question, mining companies are beginning to see that they cannot succeed into the future unless they change the way they operate.

      -Glenn Ives, Americas Mining Leader, Deloitte Canada

      The old tools are blunt

      Today’s mining companies aren’t short for choice when it comes to assessing ground-breaking technologies. From autonomous vehicles to automated drilling and tunnel boring systems, the decreasing cost of technology puts many of these innovations within reach. Even within the last few years, drone technology has taken off to the extent that easy-to-use aerial technology is now affordable – and millions of drones are sold each year. (3)

      Digital technologies already employed or that will be employed in the next 3-5 years in mining operations:

      How spatial data visualisation is rocking the mining world

      According to Anglo American, spatial data is being used more and more in the mining industry, with spatial data models and maps becoming more detailed and clearer than ever before. Today, we are seeing breakthroughs in three-dimensional (3D) modelling, Virtual Reality (VR), and Augmented Reality (AR) technology.(1)

      3D modelling creates a viewable, life-like impression with depth perception that allows the human brain to understand and relate to complex interrelated issues. VR enables a user to test a piece of equipment without the risk of damage or cost. These new technologies allow us to design new mines more efficiently and make it possible to experience what it’s like to work in a mine without being out in the field.

      Digital technologies can not only help mining companies survive, but importantly, to thrive. The productivity and safety gains of embracing new technologies are huge: better equipment performance (47 percent), operational/administrative cost savings (42 percent) and better decision making (40 percent).(3) When you add in stronger collaboration across the supply chain, safer conditions for employees being removed from dangerous working conditions and waste being eliminated – even the most risk averse of mining companies can be convinced.

      Yet to be truly successful – cutting-edge technology alone isn’t enough. While digital solutions will empower employees to make better decisions, they will also cause upheaval as manual jobs are automated. Mining companies need to consider how to create new employment opportunities, and how to reskill and retrain people to learn technology and tools faster. They’ll need to not only reach beyond traditional tools but importantly embrace the mindset and approach to collaborate.

      Technology is certainly not a silver bullet, but targeted in the right places, it will make mines even more safe, and our operations more efficient and cost-effective.

      – Dr Caius Priscu, Head of Mineral Residue Facilities, Anglo American

      Rio Tinto: Mine of the Future

      A decade ago, Rio Tinto declared one of the most ambitious transformation programs in mining: plans for an intelligent mine packed with driverless trains, trucks and robotics. At the heart of the program is an operations centre in Western Australia that today generates 2.4 terabytes of data every minute from hundreds of pieces of mobile equipment and sensors. Covering 16 individual mines, the one integrated centre (which looks very similar to NASA’s control centre) is manned by operators over 1,500km from the physical sites.

      The mining giant was also the first mining company to introduce fully autonomous haul trucks which to date have moved over 1 billion tonnes of material and travelled over 150 billion kms. But automation doesn’t stop there: it also introduced automated drills in production drilling, which is safer for operators and more efficient, and is introducing robotic automation in its rail system – a train comprised of 244 cars stretching a total of 2kms driven by robots. Next stop, possibly a mine with no miners?

      The challenges in discovering the world beneath us

      We’ve long been fascinated by the underground world of tunnels and caves, and with today’s tech it may soon be possible that ‘Google maps™’ goes underground. Yet aside from exploring the depths for knowledge, mine operators need to safely tap into and excavate the wealth of minerals beneath us. And this comes with a number of challenges:

      Access Issues
      Access Issues

      Underground mapping is one of the most difficult and demanding forms of surveying with mining professionals needing to work in tight, enclosed spaces.

      Hazardous Sites
      Hazardous Sites

      Mining sites are notoriously hazardous, despite the most rigorous safety checks. Companies strive for zero-harm targets yet the mapping process itself is risky.

      Pressure to Optimise
      Pressure to Optimise

      Tunnel construction and underground projects are time consuming and complex, and companies need to plan efficient site operations to optimise production cycles.

      Time Constraints
      Time Constraints

      Mining professionals need to rapidly and accurately map underground environments under intense time pressure, yet traditional survey techniques are slow and inefficient.

      Transforming mapping in mining environments

      Access to user-friendly technology that can quickly scan difficult-to-reach environments and produce accurate and high-quality 3D data can be a game-changer for mining operators. Leading the change is 3D mobile mapping which helps mine operators improve the way they dig up commodities as well as helping them cut costs, all without the need for GPS.

      Using a handheld laser scanner, operators can walk and scan, or attach the scanner to a trolley, drone, pole or mine vehicle for remote monitoring of hazardous environments. The scanner collects the data and SLAM (Simultaneous Localisation and Mapping) software turns it into actionable 3D information within minutes. With minimal training, operators can use it for rapid insight into rock mass behaviour, to measure stockpile volumes or to map complex tunnel profiles. Robust enough to deal with extremely harsh environments, laser scanners help mine owners deliver productivity and efficiency improvements, at the same time as keeping operators safer.

      This technology allows us to quickly and easily view, compare and evaluate data to paint a picture of what’s under the ground. It’s like an ultrasound image of the deposit delivered in real time, something that we could never do before.

      – John McGagh, Head of Innovation, Rio Tinto


      What exactly is SLAM?

      SLAM stands for Simultaneous Localisation and Mapping. SLAM devices take data from sensors to build a picture of the environment around them and where they are positioned within that environment. The complex SLAM computations and algorithms effectively construct or update a map of an unknown environment while simultaneously keeping track of the device’s location within it. Every few seconds, the scanner is comparing the data collected with the last few seconds and aligning familiar features together to create a very accurate point cloud.

      Setting a new standard for the mining and natural resource sector

      Creating highly accurate maps of the underground world, for the mining and natural resource industries, is one of the most complex forms of surveying. Yet innovations in laser technology are transforming and simplifying the way we map the world beneath us and are being applied to a wide range of applications including:

      Tunnel & Underground Mine
      Tunnel & Underground Mine
      Stockpile Analysis
      Stockpile Volumes
      Shotcrete
      Shotcrete
      Convergence Analysis
      Convergence Analysis
      Shaft Inspection
      Shaft Inspection
      Production Progress Mapping
      Production Progress Mapping

      With powerful mobile mapping technology at their fingertips, mine operators have ready access to previously unattainable insight into rock mass behaviour. This means they can better tailor their ground support regimes, monitor convergence and better target rehabilitation areas. Other benefits include:

      Rapid scanning
      Rapid scanning

      Operators can slash survey times with easy-to-use technology. Anyone on site can map accurate tunnel profiles, stockpile volumes, pits and caves in minutes.

      Go-anywhere mapping
      Go-anywhere mapping

      You can use the technology in the trickiest, darkest and dampest of spaces, even where GPS isn’t available. Walk with the handheld or attach it to a trolley, drone, robot or autonomous vehicle.

      Safety as a priority
      Safety as a priority

      You can safely scan underground, inaccessible and dangerous environments, even remote and hazardous areas.

      Save time and money
      Save time and money

      Data capture and modelling are up to 10x faster, allowing you to successfully complete projects in minimum time with little or no disruption.

      Case Study

      Mapping hazardous mines under intense time constraints

      Beck Engineering, an Australian mining engineering consultancy specialising in mining and rock mechanics analysis, needs to rapidly map mines under intense time constraints using versatile technology which is adaptable to any environment. GeoSLAM’s handheld mobile mapping solution was chosen as it is compact, portable and delivers a high level of accuracy. With GeoSLAM’s “go-anywhere” 3D technology in hand, Beck Engineering has been able to supply invaluable data regarding the direct effects of mining to better understand the implications of a deforming rock mass. Beck Engineering is now able to accurately measure the shape of an excavation or tunnel over time. As a result, tunnels are safer, better designed and more cost efficient.

      We have continued to use GeoSLAM products as they have proven to be affordable, lightweight and sufficiently robust devices for their application underground. GeoSLAM continues to produce a high-quality device that is at the forefront of practical mobile laser scanning devices.
      – Evan Jones, Senior Rock Mechanics Engineer at Beck

      Tech advancements are already helping improve mine safety, remove wastage and drive greater productivity. And mining companies are already creating jobs that require artificial intelligence or automation-specific skills – from data scientists to automation engineers. Forward-thinking operators who foster innovation will remain competitive. While some mining companies may hesitate and deliberate choosing which technology is best for them to deploy, others are decisive and lead in the race for intelligent mine of the future.

      The digital revolution is here – and it’s going underground. With unmanned technology able to carry out open-pit operations, and complex software algorithms able to mine vast quantities of sensor data, the leap to a truly digital mine is within reach.

      References

      1. Future Smart Mining – Anglo American
      2. Tracking the Trends 2018 – Deloitte
      3. Drone Sales Have Tripled – fortune.com

      Book a meeting

      With our Mining solution specialist

      Book a meeting with Owen to learn more about GeoSLAM and how it could transform your mining operations.

      Underground 3D Mapping with handheld SLAM scanners

      With the recent introduction and constant evolution of handheld SLAM (Simultaneous Localization and Mapping) scanning, mapping underground has become safer, quicker, more automated, highly repeatable, and more effective.

      Scanning a cavity with the ZEB Horizon

      Location
      Location

      Hattorf/Wintershall
      Facility, Germany

      Scanned
      Scanned

      Cavity

      Size
      Size

      70m Deep

      Scan time
      Scan time

      N/A

      Industry
      Industry

      Mining

      GeoSLAMs German dealer, Laserscanning Europe, were recently tasked with scanning a 70m deep cavity in a mine 500m below the earths surface. Using the ZEB Horizon on a cradle, Laserscanning Europe were able to successfully and safely capture the data, and this is their account of the job.

      Data captured by Laserscanning Europe

      Scanning with the ZEB Horizon | Words by Laserscanning Europe

      The object of measurement is located in the Hattorf/Wintershall mining facility of the company K+S Minerals and Agriculture GmbH. This is a cavity (underground, vertical conveyor system) about 500m below the earth’s surface with a depth of 70m.

      The cavity no longer has the original storage volume due to material deposits from years of operation. The environment is dusty and it is expected that material will be deposited within the conveyor system at any time. In addition, the cavity is not accessible to humans from any opening and access is only possible through 1m diameter openings.

      The objective was to obtain a three-dimensional survey of the conveyor system with highest possible resolution for inspection of the systems condition. Furthermore, strict compliance with all work safety regulations, with minimal risk for the measuring team, was required.

      For this job, a mobile laser scanner was used. Thanks to its specifications, the GeoSLAM ZEB Horizon is ideally suited for the special conditions underground. The scanner is also suitable for surveying a cavity that is only accessible from above through a narrow shaft.

      The scanner was mounted on a cradle, which was modified to minimise rotational movements when lowered. A 50m rope was attached to the cradle, which was used to lower the measurement system into the cavity.

      Furthermore, trained members of the mine rescue team were on site to provide security and enable the scanner to be lowered and retrieved safely.

      Measurement Procedure

      01

      Preparation of the survey: mounting of the scanner on the cradle and mounting of the rope system for lowering and raising the scanner

      02

      Starting the measurement at the upper end of the opening to the cavity

      03

      Lowering of the scanner, 50m deep, while the ZEB Horizon captures data

      04

      Raising the scanner, 50m high, while the ZEB Horizon captures data

      05

      Finishing the scanning process at the upper end of the opening to the cavity

      06

      Ascent from the mine and analysis of the scan data in the office

      Workflow of the analysis

      Following the survey, the scan data was processed using the GeoSLAM HUB software. The raw data, i.e. the processing of the point cloud from the data of the laser sensor and the IMU, is automated as much as possible. In the case that a scan was not automatically processed (e.g. because few geometric changes are found in the object space), the focus of the SLAM algorithm can be influenced by adjusting various parameters. Once the data has been run through GeoSLAM Hub, a complete point cloud of the cavity is available in .laz format. All other common point cloud formats can also be exported with little effort.

      Since the scanner could only be lowered linearly on the rope, the earth deposits shadow smaller areas inside the cavity.

      Results

      The result of this scanning is impressive. This cavity, which is not accessible to humans, was successfully surveyed with the help of the GeoSLAM ZEB Horizon. The point cloud documents the dimensions of the cavity according to the requirements. Further missions with the GeoSLAM ZEB Horizon with similar objectives are already being planned and implemented.

      Scanning Shotcrete in Mining

      Improving quality assurance & quality control whilst reducing costs

      The history of shotcrete

      Since its conception in the early 1900s, shotcrete application has developed to become one of the most critical ground supporting techniques for underground excavations.  The technology has evolved from manual nozzle handling to computer guided, hydraulically controlled boom-mounted nozzles.  By controlling variables in the shotcreting application, the layer of sprayed concrete can be optimally designed to meet the in-situ geotechnical constraints.  In some scenarios, shotcrete will be designed to flex with the squeezing rock, whilst in others, it may simply act as a barrier to protect from rock bursts.

      Understanding how the shotcrete will react in different conditions allows operators to apply the right amount of material.  Shotcrete thickness is paramount when applying shotcrete, therefore it must be monitored during application using the safest and most reliable method.  The aim of this article is to demonstrate how the SR-50 system, developed by GeoSLAM, is suitable for near real-time shotcrete application quality assurance and quality control (QA/QC).

      Shotcrete – The modern method with failing processes

      The Sika Sprayed Concrete Handbook (1) states that the only method for accurately calculating initial strength is by measuring thickness.  Current methods rely on operators endangering themselves to un-secured shotcrete in order to manually collect thickness readings.  A total of 5% of all tunneling injuries can be attributed to the shotcreting process in tunneling (2).  Industry professionals recognise the need to balance the provision of a safe working environment for its operators with the demand for increased production rates, accurately measured and documented shotcrete thickness.

      In 2016 GeoSLAM developed the SR-50 system deployed throughout the Jetcrete Australia fleet.  The technology has now been licensed to Normet Oy who have adopted the technology as SmartScan.

      SR-50 System
      SR-50 System
      SR-50 Software Interface
      SR-50 Software
      Interface

      The system provides the operator with near real-time results displaying shotcrete thickness after each application cycle with a single button press.  A colour-coded map of the spray area allows the operator to identify regions of concern easily and accurately.  Once the operator is satisfied that the sprayed thickness complies to site criteria an electronic report is automatically created.  This report documents the application cycle, providing the average applied thickness, total volume of shotcrete applied to the surface and the final thickness map that can be used for quality assurance.  All data is stored on the system for further analysis and archiving.  Without exposing the operator to dangerous conditions, the system can act as a training tool for novice operators, as well as aiding experienced operators to spray to the desired profile thickness, thus minimising overspray.

      Analysis of data collected from sites using the SR-50, showed an approximate 20% reduction in overall concrete usage.  This means that an average single sprayer operation can reach a return of investment within 2-3 months, have improved safety, and expedite the shotcrete application process.

      The system created by GeoSLAM now achieves an accuracy of less than 5mm.  This measured accuracy and reliability of measurement now enables the large-scale use of the technology on multiple sites.

      The need to modernise

      Traditional methods for measuring shotcrete thickness are based on invasive in-situ sampling at discrete points.  Samples are taken either, when the shotcrete is freshly applied, e.g., Fibercrete Depth Indicators (FDI’s) or once the shotcrete has fully hardened, e.g.  ASTM C174 drill core test.  In both cases these methods have been shown to be unreliable and disruptive to the work cycle.

      Fibrecrete Depth Indicators (FDI)

      FDI’s are used by inserting “shotcrete stamps” into freshly applied shotcrete using the boom of the spraying rig. An investigation carried out at Olympic Dam in 2018 concluded that FDI’s were incredibly disruptive to the operation as well as poor measurement technique to represent the whole heading (3). For a typical profile heading with a cut length of 4.0m, the surface area sprayed was approximately 55m2. 20 probe sites were sampled, resulting in a sample area of approximately 0.05m2, or just 0.0009% of the sprayed surface.

      Drill Core Tests

      Where drill core tests are taken most sites typically only manage to measure samples to the nearest 10mm, and again there is an element of bias towards where these drilled samples are taken from along the profile of worksite. Aside from an unsatisfactory sample size and potential for bias, the above methods either have the potential to damage the spray rig boom or are conducted hours after spraying, so any issues are not resolved at the time of application which result in time delays and extra costs.

      There is an increasing trend in tenders and contracts throughout the shotcreting industry, requiring that shotcrete thickness be accurately measured and documented across the whole sprayed surface. Therefore, new, and novel methods must be used to meet the contractual obligations whilst minimising the disruption to the work cycle. The use of Laser Scanning technologies can meet these demands by providing non-invasive measurements at the time of application; sample points that can run in to the hundreds of thousands, overcoming sample bias; all taken in a handful of minutes immediately after the application meaning that any remedial action is taken immediately.

      Laser Scanning: Accuracy benchmarks

      Terrestrial Laser Scanners (TLS) and Scanning Total Stations (STS) systems are based on laser technology and are commonly used across numerous surveying sectors where accurate range measurements are required.  Typical systems have accuracies that range from sub-mm to several mm’s depending on the underlying technology and cost.  However, in the underground environment these technologies tend to be extremely expensive, complex to use, often requiring specialist training, and can require time-consuming processing in an office environment to produce results.  The SR-50, although based on laser scanning technology was specifically designed for the shotcreting industry to be simple to use, automated, cost effective and accurate.  

      To evaluate the accuracy of the system a rigorous approach was developed.  The assessment criteria relied on the use of a TLS (Riegl VZ-400) that was deployed in a controlled environment.  The TLS was chosen on the premise that to assess the accuracy of the SR-50, the reference data must of greater accuracy than the test data.  The ability to control any changes in the environment was paramount to avoiding ambiguities in the results.

      An artificial tunnel environment was constructed with cross-sectional dimensions similar to those in the mine tunneling environment.  After an initial base scan of the environment, using the TLS and SR-50 a series of control-panels of known thickness (verified using vernier callipers) were introduced at varying positions in the tunnel.  After each control-panel was introduced, changemaps were calculated from SR-50 and the TLS data. Thicknesses of 8, 13, 18 and 30mm were used.

      The Results

      The first assessment of the SR-50 system was to compare comparison results of the test environment with no change against the results using the TLS. Since, there was no physical change to the environment this provided an indication of the repeatability of the system. This assessment was then repeated by placing 8mm, 13, 18 and 30mm boards into the scene and measuring the average thicknesses using the SR-50 and TLS data.

      The top image shows the comparison map derived from the SR-50 when no change was made to the environment. The middle shows a comparison of the computed changemap from the TLS control-panel (LHS) and the panel measured by the SR-50 (RHS), both for a 13mm control-panel. The figure clearly shows that the SR-50 gives comparable results to the TLS. The changemap for the TLS gives a more consistent result due to the much higher point density. However, the measured average change across the panels are the same. Control-panels were also attached to the sides and shoulders of the test area and an example changemap is shown in the bottom image.

      Board Thickness (mm)081318
      Smartscan Selection Mode Difference (mm)0000
      Third Party Difference (mm)0111

      The above table provides results for the comparison between the average thickness of the control-panels measured using the TLS and SR-50. To assess the accuracy of the automated changemaps created in the SR-50 software, the raw data was exported and thickness maps were calculated in a 3rd party software. The results show good agreement with the on-board solution available at the time of spraying.

      Conclusion

      By using laser technology and scanning the working area before and after shotcrete application, shotcrete thickness is automatically calculated across the complete working area in near real-time.


      To provide an initial assessment of system accuracy, a series of measurements were undertaken in a man-made, controlled area. A series of control-panels of known thickness were introduced into the environment and thickness maps calculated by the SR-50 were compared to maps created using a Terrestrial Laser Scanner of much higher specification. Additionally, the results automatically created by the system were compared against results created manually in a 3rd party software package.


      The results showed that thickness maps created using the SR-50 system were comparable to a TLS system. Average control-panel thickness was typically within 1-2mm between the two systems. The investigation shows that the SR-50 is accurate and reliable enough for the shotcreting industry. When comparing to the inaccurate in-situ measuring the industry has previously adopted (such as the ASTM C174 drill core test), the SR-50 can provide reliable results across the whole sprayed face in near-real time. The system is able to:

      Provide an accurate thickness report every time a spray is required

      Drastically reduce shotcrete wastage by helping the spray application process in achieving its desired thickness in a single attempt

      Ensure geological ground control is achieved and upheld during the full shotcreting operation

      Help nozzle-persons gain experience in spraying by providing near-real time thickness results.

      As shotcreting becomes more common in mining and infrastructure projects around the world, the industry needs to evolve to accept the need for strong QA/QC methods and reporting in near-real time.


      References

      1. Sika Services AG. (2020). Sika Concrete Handbook. Available: https://www.sika.com/content/dam/dms/corporate/t/glo-sika-concrete-handbook.pdf. Last accessed September 2020
      2. Kikkawa N, Itoh K, Hori T, Toyosawa Y, Orense RP. Analysis of labour accidents in tunnel construction and introduction of prevention measures. Ind Health. 2015;53(6):517-521. doi:10.2486/indhealth.2014-02
      3. Unpublished site report: Olympic Dam, BHP, 2018.

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      Mapping a gold mine with the ZEB Horizon

      Industry

      Mining

      Scan time

      15 minutes
      per scan

      Location

      Nevada,
      USA

      Size

      5 miles of
      mine tunnels

      Scanned

      Pamlico
      Ridge

      The state of Nevada is currently the fifth largest gold producer in the world. First discovered in 1849 by prospectors on their way to the California gold rush, gold and later silver caused several booms, with production really picking up in the 1960s thanks to new metallurgical techniques which meant recovery of more gold than ever before. Looking at old mines from the 1800s with our modern perspective provides great opportunities.

      Newrange Gold is bringing new things to old places at the Pamlico project, which was one of the highest-grade gold districts in Nevada in the 1880s. Records of the mine workings are lost and the workings have never been systematically studied, leaving an enormous opportunity to map, survey, and sample the old exposures. With 5 miles or more of historic mine tunnels dating from the period of 1884 to about 1928, you can understand why no-one has done it before: it would be too time-consuming and costly to do with conventional surveying.

      My company, Carrington Consulting, invested in the ZEB Horizon to expedite surveying, mapping and sampling at our client company, Newrange Gold Corp., at the Pamlico project. Systematically scanning the complex, interconnected workings has generated an unprecedented 3D map of the mine workings and has resulted in greater than 50% savings to date over conventional surveying and mapping techniques.

      Our experience with the ZEB Horizon so far is vastly superior to traditional methods and is an indispensable part of my exploration toolkit.

      In addition to revealing very subtle structural details of the geology, this mapping will form an essential part of modelling historic production and the remaining gold resource at the project going forward. This revolutionary hand held LIDAR scanning technology allows us to complete extremely accurate underground geological and sampling maps, volume analysis of material moved, and careful planning of exploration drilling to better calculate mineral resources in preparation for possible resource definition and mining at Pamlico.

      Carrington Consulting’s team is scanning more than 5 miles of tunnels at Pamlico for Newrange. These workings extend over an area more than 1,500 feet long and 800 feet wide with a vertical depth of roughly 300 feet and form an extensive network of adits, tunnels, stopes and raises with at least 30 major entrances that are largely interconnected. Scanning is tied to established surface survey control for registration and orientation so the scan can be accurately carried underground. Underground survey control points are established using a series of spheres to allow Newrange’s geologists to later reoccupy the points to complete the geological mapping.

      Many of the mine workings are less than a metre wide and in some cases, they are also less than a metre high following the gold vein, wherever it goes, forming a very irregular, complex network of tunnels and stopes. It would be prohibitively slow and expensive to do this essential mapping with conventional surveying or terrestrial scanning, but the ZEB Horizon makes it realistic for Newrange to accomplish this ambitious goal.

      As always safety is paramount, especially when entering old mine tunnels and stopes. With the 100 meter distance capability of the Horizon no one needs to go into unsafe areas. In addition virtually every timber, ladder, and detail are recorded.

      We have produced highly accurate data of mine workings up to ¼ mile in length in less than 15 minutes, which changes the game for Newrange at Pamlico. As Newrange gathers information on gold grades from sampling throughout these workings, we are integrating additional layers of information to build a comprehensive 3D model of the geology across the entire area of old underground workings.

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      Newrange Gold logo