Skip navigation

C-ALS® borehole-deployable laser scanner for concealed cavity and void scanning

C-ALS (Cavity Auto-scanning Laser System) is a unique specialist underground laser cavity monitoring system that enables mapping of previously inaccessible parts of mines, safely and quickly.

C-ALS grants access to concealed cavities

C-ALS cavity monitoring system can be used in a wide range of applications, where an inaccessible void exists and accurate data is required to monitor excavations, assess risk or design solutions.

Once deployed, C-ALS gives more detailed, accurate data than alternative technologies, such as ground-penetrating radar, and is the only borehole-deployable laser solution on the market.

  • Plan new projects: Assess risk, design solutions based on accurate underground data, add C-ALS data to your existing maps and devise new programmes of work.
  • Transform productivity: With accurate maps of voids, you can design plans, which allow for efficient mining or construction projects.
  • Improve safety: Map inaccessible underground areas to ensure operations keep employees safe.

C-ALS supports successful projects

Ruggedised PC for C-ALS

C-ALS gives you new underground mapping capabilities. You can safely, quickly and reliably scan inaccessible underground workings. Our Cavity Profiler software gives you modelling, manipulation and export capabilities. The system enables you to collect the data you need in order to:

  • protect worker safety
  • show compliance
  • report to project stakeholders in greater detail
  • cost out planned works accurately
  • devise more efficient programmes of work
  • progress new projects
  • design and engineer solutions based on accurate data
  • minimise disruption, drilling and disturbance in populated areas

Advantages of C-ALS laser scanning

3D cavity scan

The unique 50 mm diameter of C-ALS allows access to voids via narrow boreholes, which minimises scanner deployment time and cost. The 360° spherical coverage provides a full view from a single scan, with no blind spots. In addition, the C-ALS laser scanner also enables you to:

  • use remote-control operation to survey potentially dangerous underground voids safely
  • view the results of your scan in minutes, not days
  • work safe in the knowledge that an IP67 rating gives you the confidence that C-ALS will operate in wet, humid and dusty conditions. It can also withstand submersion to a depth of 1 m, reducing the risk of damage if C-ALS is accidentally deployed into a flooded cavity.

Case studies

How it works

C-ALS and borehole

With a diameter of just 50 mm, C-ALS cavity monitoring system is easily deployed downhole or uphole through boreholes to survey inaccessible spaces.

A system of hinged, lightweight 1 m rods provides a fixed azimuth capability, and enables C-ALS deployment down boreholes as long as 200 m. C-ALS can also be deployed by boom or by remote-controlled vehicle.

A nosecone camera gives full visibility of the borehole during deployment, so operators can see any obstructions, and judge when C-ALS has entered the void.

The C-ALS probe incorporates pitch-and-roll sensors and has the option of an internal compass. The sensors ensure C-ALS can be tracked down the borehole and that the scan is automatically georeferenced to fit into existing 3D mine data.

Once in the void, a simple click from the operator tells the laser-scanning head to rotate on two axes, measuring the three-dimensional shape of the void with full 360° coverage and no blind spots, and with a range up to 150 m.

A load-bearing cable attached to the probe transmits all the measured data back to the surface unit and a ruggedised computer loaded with our Cavity Profiler software is used to control C-ALS from a safe location and to view the data in real-time.

Renishaw's new user-friendly Cavity Profiler software for C-ALS makes it quicker and easier for operators to use the system, by guiding them through the process of deploying and scanning.

The dangers of underground voids in 90 seconds

  • Animation: C-ALS®

    Our 90-second animation explains the dangers that underground voids can pose, and shows how customers can keep workers safe and maximize productivity.

Applications where C-ALS provides data when manned entry may not be possible:

  • sub-surface voids and cavities
  • undercrofts
  • underground chambers and tanks
  • duct surveys
  • inaccessible roof spaces
  • subsidence investigations
  • collapsed mine workings
  • culverts
  • shafts and bunkers
  • underground caverns
  • industrial production facilities where access is limited or unsafe


C-ALS offers new capabilities, safety and cost benefits in a wide range of underground applications.


  • Brochure: C-ALS® Cavity Auto-scanning Laser System Brochure: C-ALS® Cavity Auto-scanning Laser System

    C-ALS is a unique laser system that gives you new underground mapping capabilities. You can safely, quickly and reliably scan inaccessible underground workings, and upload the scan data to your existing mapping software.

  • Data sheet: C-ALS® Cavity Auto-scanning Laser System Data sheet: C-ALS® Cavity Auto-scanning Laser System

    Detailed list of technical specifications and dimensions for Renishaw’s C-ALS Cavity Auto-scanning Laser System, the borehole-deployable laser scanner for concealed cavity and void scanning. With its unique 50mm diameter, C-ALS can enter otherwise inaccessible areas through very narrow, more cost-effective boreholes, enabling you to map subterranean cavities and plan safer, more effective operations.

  • Manual: C-ALS® Manual: C-ALS®

    Renishaw’s C-ALS® is a ruggedised 3D laser scanning system. With a diameter of just 50 mm, the unit is designed to be deployable through boreholes for surveys of underground voids and cavities. The C-ALS measures the three-dimensional shape of the void and also its surface reflectivity.

Image gallery