LiDAR technology has transformed a wide variety of industries ranging from space exploration to autonomous vehicles and even video games. Its impact has been particularly profound on the mining industry where LiDAR is seeing increasing adoption throughout mines globally. Specifically, mines use LiDAR technology for mapping purposes in order to capture essential geological data. In this article we’ll explore the different types of LiDAR and why this technology is becoming increasingly critical to mining operations around the world.
What is LiDAR mapping?
Light Detection and Ranging, also known as LiDAR, has been a critical remote sensing tool in various geospatial survey industries for many decades. It is both a fast and accurate technology that can be used in a wide range of environments and conditions. In the simplest of terms, LiDAR is a depth sensing technology used to collect data that informs and supports decision making. In the mining industry, LiDAR is used to provide spatial context for considerations such as overbreak, ground support requirements, identification of geological features, stock pile estimates, and general surveying.
The graphic below shows a breakdown of the various types of LiDAR. While there are many types of LiDAR that exist, all operate under the same principle of the reflection a surface to generate a highly detailed 3D pointcloud model. In this article, we’ll focus on the two types of Terrestrial LiDAR most commonly used in underground mining: Flash and Scanning LiDAR.
1.) Flash LiDAR
In principle, Flash LiDAR works in a similar way to scanning LiDAR, but instead of measuring a single point at a time, the entire field of view is illuminated with a wide diverging laser beam within a single pulse of energy. Flash LiDAR’s structured light uses a near-infrared pattern projected across the space in front of the sensor, and an infrared sensor captures the reflected light pattern. This pattern is deformed by the relative depth of the objects in front of it, which can be used to estimate the distance of the object from the sensor. Flash LiDAR is optimal for scanning at a short range, and gives the user a quick response, with very high amounts of detail. Today this technology is most commonly used in gaming console systems to detect body movements, but new Flash LiDAR innovations are now increasingly used in underground mines.
2.) Scanning LiDAR
The most commonly seen LiDAR method, this technique uses laser pulses to reflect off a 3D surface and measures the bounce-back time to the sensor to replicate the surface as a detailed 3D model. Using a collimated laser beam, this method measures a single point at a time. One of its major benefits is its versatility, as it can be used for many applications from airborne to stationary or mobile devices. Additionally, scanning LiDAR can scan from a wide variety of distances ranging from less than a meter to over 200 meters, and can scan up to 360 degrees. Generally, this type of scanning is used on surface or underground in a variety of climatic conditions.
What is Mobile LiDAR?
Mobile LiDAR, as indicated in its name, enables users to capture data while moving. This technology has recently expanded into the underground mining sector within the last decade, and has mostly been used in the self-driving automotive, drones, and robotics space.
How does it work?
As a traditional scanning LiDAR system, Mobile LiDAR is often constructed in the form of a rotating “puck” scanner which sends out laser pulses capturing a high density pointcloud 3D map of its surrounding environment. Mobile LiDAR uses a Simultaneous Localization and Mapping (SLAM) internal system in order to locate itself as the user is moving the system in space. This enables users to capture high quality 3D models of large areas very efficiently. The SLAM algorithm tracks the devices position in 3D space by comparing it to its previous position or previous “frame”. The scanner then maps the environment and sequentially positions itself by matching the pointcloud features using registration algorithms. For best results, it is always recommended to “close the loop” for any mobile scans: essentially you must start and end in the same location.
What are the key benefits?
The flexibility of mobile LiDAR unlocks many different uses of the scanner including hand-held walking, mounting the scanner to a vehicle, and even mounting scanners to mobile robotics systems or drones for fully autonomous data capture. Another major benefit of this technology is the reduction of pointcloud shadow that allows the scanner to “see” features from a variety of angles.
What is Static LiDAR?
In a mining environment, static scanners are most often used by survey departments to generate georeferenced 3D representations of their environment and detect changes.
How does it work?
Static LiDAR collects information from a static position in space and is most commonly used by mounting a scanner to a tripod, but can also collect information with a handheld device if maintained stationary during data capture.
What are its key benefits?
The major benefits of this type of LiDAR are its phenomenal detail, offering some of the most detailed short range LiDAR scanners on the market today. They also offer some of the longest range for those looking for lower resolution by scanning 3D surfaces over 100m away.
What’s all the hype?
So why is the mining industry so excited about LiDAR technology? There are five key reasons:
1.) Safety- Safety concerns are a top priority for mines across the globe. LiDAR technology enables users to scan rock faces at a distance. This reduces exposure to potentially dangerous conditions and/or previously inaccessible locations, which dramatically improves safety in underground mines.
2.) Efficiency- With faster turnaround times within the technical department, LiDAR helps to reduce production delays, which enables significant increases in efficiency.
3.) Accuracy- LiDAR technology allows for efficient and high-quality data capture with optional automation customization.
4.) Cost-effectiveness- With better design the first time, mines can avoid having to re-enter data for adjustments or fixing design errors. This in turn reduces both equipment and personnel costs.
5.) Improved decision making- High resolution datasets empower teams to make better engineering decisions on items such as mine design, geotechnical risk, and production.Want to learn more about LiDAR in the mining industry?
Our team of experts can help you unlock the power of LiDAR to improve accuracy, safety, and efficiency in your mine site. Learn more about RockMass LiDAR solutions by connecting with our team.
By Sierra MercerSierra Mercer is an alumnus of Queen’s University Geological Engineering and is currently working as a Geotechnical Engineering Specialist at Rockmass Technologies. With a background in ground control for underground mining, she has been involved in the testing and development of various LiDAR systems, UAVs and cutting edge advanced robotic systems in underground environments. She is passionate about innovation in mining technology and continuously works to bring new opportunities to modern mining operations.
